Diseases of cultivated crops in Pacific Island countries

Eric McKenzie

Diseases are a significant limiting factor for papaya production. The nature and frequency of these diseases depend on local conditions and effective management depends on a thorough knowledge of the pathogen, host plant, environment, and their interaction. The precise identity of the causal agent is of paramount importance, and disease management options must be economical. Assessment of disease incidence or severity, and fruit loss are the key factors in determining the economics of disease management. In general, disease management strategies involve different practices that include plant resistance, and prophylactic and curative measures. The papaya diseases related have diverse etiologies, divided into those with biotic (infectious) and abiotic (noninfectious) etiologies that affect the fruit and those affecting the plant. We have attempted to emphasize procedures for diagnosis and control with detailed information on each. Descriptions of pathogens are provided in sufficient detail to assist professional diagnosticians in making accurate diagnosis. Fungicides used to control many of the diseases described in this chapter are mentioned for information proposes only. Legal restrictions and regulations of fungicide use vary among countries, and regulations within any country are subject to change over time. The information reported has been extracted from the available scientific literature and the authors’ experience, and we hope that this publication will provide a helpful reference to growers, students, and professionals working with papaya.

This paper reports for the first time the occurrence of papaya black spot (Aspensporium caricae) m Sri Lanka, a disease previously confined to South and Central Americas and Africa. In early 1992 we noticed an unusual disease m the mature leaves and the fruits of several papaya cultivars in Hantana located about 2 miles from the Kandy town. The disease

The isolated eight fungi were found associated with fruit rot of papaya and differentiated in cultural and morphological characteristics. The fungi were identified on the basis of cultural and morphological characters. The fungi were Colletotrichum gloeosporiodes, Graphium sp., Fusarium pallidoroseum, Alternaria alternata, Fusarium solani, Aspergillus niger, Aspergillus flavus, Rhizopus microspora. The pathogenicity of isolated fungi was proved by knife injury, cork borer injury, and pin prick injury methods on papaya fruits.

Franz KOHLER - Frédéric PELLEGRIN - Grahame JACKSON - Eric McKENZlE Diseases Cultivated Crops Pacifie Island Countries ......... .. .... .. l ,) '-.. ... South Pacifie COlllmissiull ｎｯｵｭｾ｡Ｎ Nl'\\ Cakdllllia IlllJï South Pacifie Commission cata1oguing-in-publication data Diseases of cultivated crops in Pacifie Island countries 1 by Franz Kohler, Frédéric PeJJegrin, Grahame Jackson and Eric McKenzie 1. Vegetable-Diseases and pests-Oceania 2. Fruit-Diseases and pests-Oceania 632 ISBN 982-203-487-3 Agdex 201 © South Pacifie Commission, 1997 Published by the South Pacifie Commission Printed by Pi rie Printers Pty Limited, Canberra, Australia Published with financial assistance from the AustraJian Centre for International Agricultural Research, Canberra Originally pubIished in French as: F. Kohler, F. Pellegrin-Pathologie des végétaux cultivés, symptomatologie et méthodes de lulle. Nouvelle Calédonie, Polynésie Française, Wallis et Futuna (Crop diseases: symptomatology and control in New Caledonia, French Polynesia, Wallis and Futuna). © ORSTOM Editions 1992. ISBN 2-7099-1113-2 Contents Foreword 1 Symptoms and treatments 3 Control measures 153 References 179 Index of hosts and pathogens 181 This book is dedicated to the memory of Ivor Firman, former SPC Plant Protection Officer, who spent most of his working life in the Pacifie. He is remembered not only for his contribution to our knowledge of plant diseases in the Pacifie and their control, but also for the wit and good humour with which he carried out his work. Foreword In 1992, the Institut Français de Recherche Scientifique pour le Développement en Coopération (ORSTOM) published Pathologie des végétaux cultivés, a manual on plant diseases of New Caledonia, French Polynesia, and Wallis and Futuna. The authors, Franz Kohler and Frédéric Pellegrin, realising that many of the diseases in these three territories were common to other Pacific Island countries, proposed an English version. The South Pacific Commission welcomed this idea and sought financial support for the project from the Australian Centre for International Agricultural Research, Canberra. This was generously provided. The purpose of the manual is to assist extension personnel and farmers in the identification of important plant diseases in their countries and to give them information on options for control. It is hoped, too, that the manu al wiU have a place in schools. It could provide a useful reference for crop protection in the agriculture curriculum, assisting in disease recognition and control measures using both traditional and modern techniques. It is realised that for many growers in Pacific Island countries, control options are limited. Pesticides are often difficult to obtain, are costly, and, in many small islands and atoUs, environmental concerns may precJude their use. For the se reasons the manual emphasises cultural contrais and the use of plant varieties toJerant to disease. In order for the English edition of the manua1 to be relevant to aU the countries and terri tories of the region served by the South Pacific Commission, sorne 70 extra diseases, in addition ta those of the French version, are described and illustrated and methods are prescribed for their control. Many scientists, both those working in the region and those in countries outside, have contri buted photographs from their personal collections, and are thanked for their generosity. These include John Bridge, International Institute for Parasitology; Richard Davis, Australian Quarantine Inspection Service, Mike Ivory, University of Oxford; Leon Mu, Service de J'économie rurale, Papeete; Mike Pearson, University of Auckland; Semisi Pone, South Pacifie Commission; Chris Prior, International Institute of Biological Control; Brian Thistleton, South Pacifie Commission; John Randles, University of Adelaide; John Thomas, Department of Primary Industries, Queensland; Fauoro Vilsoni, Koranivia Research Station; George Wall, University of Guam; and Bill Zettler, University of Florida. Photographs were also kindly provided by staff of the Bureau of Sugar Experiment Stations, Queensland. Many of the photographs have appeared previously in three plant disease publications. On pages 9,15,17,19,21,25,27,31,51,53,55, 63, 115 and 137 certain of the photographs are from Plant diseases of Western Samoa by Wolfgang Gerlach, published by Deutsche Gesellschaft für Technische Zusammenarbeit (GTZ) GmbH. And sorne of those photographs on pages 7, 9, 15, 19, 21, 31, 37, 63, 65, 73, 85, 87,89,91,93,103,109, Ill, 113, 117, 119, 121, 127, 133 and 151 have been provided by the Department of Primary Industries (DPI), Queensland from their books, Diseases offruit crops and Diseases of vegetable crops published by the DPI, Queensland. The authors of these texts and the publishers are thanked for their generosity in sharing the photographs for use in this manual. In addition, we are grateful to Denis Persley and Tony Cooke for arranging the duplication of plant disease photographs from the collection maintained by DPI, and to Robin Palmer for taking photographs of plant diseases in Fiji. Mlich more needs ta be done ta make this manual a comprehensive well-illllstrated collection of important plant diseases of Pacifie Island cOllntries. Readers may find sorne diseases of interest are not inclllded, and, for sorne that are present, the photographs could be improved. This is acknowledged, and the challenge now is to get the illustrations required. It is, therefore, hoped that readers will assist the South Pacifie Commission by contributing photographs for future supplements to the manual. These will be published in the same format as weil as on CD-ROM, and incorporated into the Pacifie Plant Protection Information System. Dr Bob Dun Director-General South Pacifie Commission Noumea, New Caledonia 2 Key fa the Symptoms Site of infection R C S,T L FI Fr Root Collar Stem, Trunk Leaf Flower Fruit Importance of the disease -V -V-V -V-V-V «(11/1/01'/'('(11/111'/11,1 : The lIul1lhcr givcn (\Ir \ta 'h ､ｬｾｴＺ｡Ｌ･ Minor Moderate Severe ｾＧｮｩｉ､ｴＺｳ with control Jl1casurc' dewiled on pagl" 15 177 3 ABELMOSCflUS ESCULENTUS 1'1CACIA. SPIRORBIS OKRA MALVACEAE WATTLE MIMOSACEAE Pseudocercospora abelmo...chi Uromycladi1111l tepperianul1l Glomerella cinglllflta =Culletolrichul11 gloeQ.\porioides Leafspot Rust Anthracnose Site of infection: L Site of infection: L,Fr Site of infection: L Importance of the disease: '1/ Importance of the disease: ....;....; Importance of the disease: '1/'1/ Symptoms Symptoms Symptoms Angular spots, mostJy on mature Jeaves, at first yellowish on the upper Jeaf surface, later becoming brown. On the lower surface, the spots become covered with grey or brown fungal growth. Usually, the spread of the spots is restricted by the veins. Bele, A. manihot, is also a host. Large, hard, irregular knobs or galls, up to 150 mm across, formed within the 'leaves' (Ieaf-like petioles) and fruits. The galls are light brown when young and spore-producing, becoming dull brown with age. In severe attacks, the trees may be full of galls, and made weak by the reduced leaf canopy. Seed production may be affected. Several Acacia spp. are hosts. Another rust, Uromyces phyllodiorum, occurs on Acacia spp. The spore-producing pustules are light brown and occur in groups, deforming the pods and flowers. Light brown leaf spots, without clear margins, merging as they age and affecting a large part of the leaf blade, giving a scorched appearance. Leaf stalks are seldom attacked. Kiwi fruit is a recent introduction into the Pacifie Islands and, as yet, has not been planted widely. Colletotrichum, however, has the potential to cause a serioLls problem on this crop. Many other plants are hosts, including avocado, coffee, eggplant, mango, papaya. sweet pepper. tomato and yams. Treatment: 4 110 Treatment: ACTlNIDIA DELICIOSA KIWI FRUIT ACTINIDIACEAE 144 Treatment: 62 Photo: Eric McKel1zie Ph",,,: Kohler Colleuiol1 Phnlo: Kohler ColleclÎt}/1 Photo: Eric A1cKeflzie PW'/ft/O(l' r("o.\/)( ml (1 he/lIIost.'h i Photo: Kohler Colleclion UnJ/1Iydl1liiU/II tepfJerÙl11ll11/ Glomerel/a L'ingu/ara 5 AGATHIS SPP. AGATHIS SPP. ALUUM CEPA KAURI ARAUCARIACEAE KAURI ARAUCARIACEAE ONION ALLIACEAE Aecidilll1lfragifonlle Glomerella cillKulala =Colletotrichu11l gloeo!>porioides Rust Anthracnose Smudge Site of infection: L Site of infection: L,S Site of infection: L Importance of the disease: 1/ Importance of the disease: 1/ .olletotridlllm circinan... Importance of the disease: 1/ Symptoms Symptoms Symptoms Raised galls, 5 mm high, on the upper leaf surface, up to 15 mm diam. The corresponding lower leaf surface is often depressed. White to yellow pustules are formed within the galls. The galls are more common on younger plants, sometimes causing defoliation. The disease is mostly a problem on seedlings in the nursery, where it can cause substantialleaf fall, weakening and ev en kiUing the plants. Many other plants are hosts, including avocado, coffee, eggplant, mango, papaya, sweet pepper, tomato and yams. Small, round, dark blotches on the bulb and zonate patterns on the outer scale leaves, particularly on white-skinned varieties. Treatment: 6 2 Treatment: 62 Treatment: 34 Photo: Kohler Collection Photo: Kahler Collection Phoro: DPI ColieCiion Photo: Kahler Collection I\ecidi 1111I lm l{ ifo l'III (' G/o!nerella cil1gll/attl CollerorricllLl1ll cir("Îlluns 7 Al.LTUM PORRUM ALLIUM SATlVUM ALOCASIA MACRORRHIZOS LEEK ALLIACEAE GARLIC ALLIACEAE GIANTTARO ARACEAE A Ltemaria ponoi Aspergillus lIiger MYl.'osp/werella 1lloclL\"iae =Cerl.'o pora colocasiae Purple blotch Mould Leafspot Site of infection: L Site of infection: L Site of infection: L Importance of the disease: -J-J Importance of the disease: -J Importance of the disease:-J Symptoms Symptoms Symptoms Small, white spots on the leaves, spreading under moist conditions into large oval purple lesions with yellowish borders, up to 150 mm long. Dark fungal growth containing spores of the fungus occurs at the centres of the lesions. Infection results in leaf-tip dieback, with the leaves drying out and collapsing after 3-4 weeks. A yellow ta reddish watery rot may accur in the bulb. Other Allium spp.-garlic, onion (lower photograph) and shallot-are hosts. On garlic, a dry rot, associated with dark brown to black spore masses. On on ion, (lower photograph), the fungus occurs on the outer scale leaves, especially along the veins, and may cause a neck rot. Aspergillus niger is a common soil fungus. Spores are carried on the surface of the cloyes, and cause rots if storage condi tions are poor. Other plants are hosts, including coconut, maize and peanut. Small, round or irregular spots with grey centres and brown margins, often with yellow haloes, up to 8 mm diam., but smaller on heavily infected Ieaves. Fungal fruiting bodies are often visible on the upper leaf surface as small black dots. The spots are usually only present on the older leaves. Treatment: 8 8 Treatment: 10 Treatment: 81 Pholo: Kohler Col/eClio" PholO: Kahler Col/eelio" Photo: Eric McKenlie PholO:Wo/fgong Gerlach Altemaria porri Photo: DPI Col/eClio" Aspergillus niger My m'p!laerellll afoctl'i/llt' 9 ANANAS COMOSUS ANNONA SQUAMOSA ANTHURlUM ANDREANUM PINEAPPLE SUGAR APPLEISWEETSOP ANTHURIUM BRüMELlACEAE ANNüNACEAE ARACEAE Ceratocystis paradoxa =Chafara paradoxa GfomerefÙl cïllglliata =Cofletotrichul1I gloeosporioides Glomerella dllgulllta =ColietotricJllIl1I gloeosporioide Water blister and soft rot Anthracnose Anthracnose Site of infection: Fr Site of infection: L Site of infection: L,S Importance of the disease: ,f,f Importance of the disease: ,f Importance of the disease: ,f Symptoms Symptoms Symptoms Soft, watery fruit rot at first, leaving the brittle outer shell intact. Later, the skin, flesh and core break down and the fruit leaks through the shell. The rots are often associated with wounds. On the Jeaves, long (up to 200 mm), cream to white papery spots form with brown margins. A soft, grey to black butt rot may also occur after planting, creating a cavity at the base of the stem and resulting in stunting or death. Other species are also hosts: banana (crown rot of fruit bunches), coconut (stem bleeding), sugarcane cuttings (pineapple disease). Brown areas of rot, spreading along the veins and leading to total infection of the leaf. Occasionally, the fungus causes partial or severe defoliation. Many other plants are hosts, including avocado, coffee, eggplant, mango, papaya, sweet pepper, tomato and yams. Round black spots with yellow margins on the leaves, especially at the margins. The centres of the spots may faU out as they enJarge. The disease is important on plants grown under shade or in screenhouses, as it spoils the appearance of this ornamental plant. Many other plants are hosts, including avocado, coffee, eggplant, mango, papaya, sweet pepper, tomato and yams. Treatment: 10 24 Treatment: 62 Treatment: 62 Photo: Kohler Collee/ion erllfOn'\fi.\ !'arodo.w Photo: Kahler Collecrion Photo: Kahler Collection G/()11/ al'! Iii ( i 1/ g /II III fl 11 ANTHURIUM ANDREANUM APIUM GRAVEOLENS APIUM CRAVEOLENS ANTHllRIl1M ARACEAE CELERY CELERY APIACEAE APIACEAE Fusa";1I1ll o.xY.\POrlllll Glomerella cinglilata =Colletotricllll111 '/oeo.,\porioÎl!es Physiological disordel' Root and collaI' rot Anthracnose Brown heart Site of infection: S,C,R Site of infection: L,S Site of infection: L,S Importance of the disease: -V-V Importance of the disease: -V-V Importance of the disease: -V-V Symptoms Symptoms Symptoms Decay of the collar region and roots causes plants to wilt. In the screenhouse, the disease is rapidly spread in water used for irrigation. Dark brown areas of rot rapidly spreading through the leaf blades and stalks. The fungus is capable of destroying the en tire base of the ceJery plant. Many other plants are hosts, including avocado, coffee, eggplant, mango, papaya, sweet pepper, tomato and yams. A black wet rot of the leaf base and apical bud associated with boron deficiency. The necrotic tissues are often invaded by opportunistic bacteria and fungi which cause further decay. Treatment: 12 55 Treatment: 62 Treatment: 19 Photo: Kohler Collecriol1 Fusurillfl/ ox)','[JO/ï/111 Phoro: Kohler Collecriol1 Glomerella cÎngulata Phoro: Kohler Collecrioll Physiological clisord r (Brown heaI1) 13 ARACHIS HYPOGAEA PEANUT ARACHIS HYPOGAEA PEANUT ARACHIS HYPOGAEA PEANUT FABACEAE FABACEAE FABACEAE Alltelia ro(fsii =Sderotium ｲｯＯｪｾＧｩ Mycm.pltaerella berkeleyi =CercosporidiU11l per'lOlIohl11l Puccinia aracltidis Basal rot Late leaf spot Rust Site of infection: S,R Site of infection: L Site of infection: L Importance of the disease: ｎｾ Importance of the disease: ｎｾ Importance of the disease: ..,j..,j Symptoms Symptoms Symptoms Initially, a wilt of a single leaf or branch, rapidly followed by a wilt of the entire plant. The base of the stem becomes covered in white fungal growth in which smaIJ, 1-2 mm diam., sclerotia develop. These are at first white and later light brown as they mature. During warm wet weather the fungus spreads from plant to plant. A wide range of cultivated plants and weeds are hosts, iocluding beans, carrot, cucurbits, sweet pepper, sweet potato, taro and tomato. Light to dark brown spots, 1-10 mm diam., with or without a yellow halo. Spore masses of the fungus form on the lower leaf surface. Early leaf spot, caused by M. arachidis, also commonly occurs. The yeJlow halo may be more noticeable, and spores develop on the upper leaf surface. The two may be present together on the same leaf. Because symptoms are similar, microscopie examination is required to separate the species. Brown pustules on the under surface of the leaf, often with a yellow halo. The Ieaves turn yellow, dry out and fall. Treatment: 14 11 Treatment: 82 Treatment: 117 Photo: DPI Collection Photo: Mike Pearson Photo: Wolfgang Gerlach Photo: Wolfgang Gerlach PIIOIO: Wolfgong Gerlach Pholo: Eric McKenzie Afhelia roiI,"ii Mycmplwerelfa berkelevi P,ICÔIlÙI amât/dis 15 ARANDA SP. ARANDA üRCHID ARTOCARPUS ALTILIS ARTOCARPUS ALTIUS BREADFRUIT BREADFRUIT ORCHIDACEAE MORACEAE MORACEAE Glomerella c:ïl1gu/ata Ulsiodiplodia theobromae =Botryodip/odia theobromae PllellillllS noxiw; =Colletotr;t'h li III g/oeosporioides Anthracnose ColJar rot Brown root and collar rot Site of infection: L,S Site of infection: T,C Site of infection: T,C,R Importance of the disease: ...j Importance of the disease: ...j Importance of the disease: ...j...j Symptoms Symptoms Symptoms Large, oval, rapidly expanding spots with broad water-soaked margins on the leaves. In severe attacks, plants may become defoliated and even killed. Fungal fruiting bodies develop in concentric rings, producing pink spore masses and sometimes small black structures containing the sexual stage of the fungus. The sa me symptoms occur on species of Cattleya, and a severe disease also occurs on vanilla. Many other plants are hasts, including avocado, coffee, eggplant, mango, papaya, sweet pepper, tomato and yams. Dry rot of the collar and trunk associated with externat white strands of the fungus. Beneath the bark, the wood shows white patches with dark brown margins. This disease has only been recorded on plants from Wallis and Futuna held in quarantine. Many other plants are hosts, including banana (post-harvest crown and fingertip rot); passionfruit (associated with collar rot); cocoa (associatcd with Phytophthora pod rot); and papaya (fruit and stem rot). A brown crust, sometimes with a white margin, up to 1 m, on the base of the trunk. The wood beneath the crust turns brown. Roots are covered with the sa me crust; characteristically soil particles are attached, giving the root a rough appearance. As the crust develops on the outside of the tree, branches begin to die back, leaves and fruits fall, and eventually the entire tree dies. Many other trees are hosts, including cocoa, coffee, Leucaena, mango, oil palm and forest trees (Eucalyptus spp.-lower photograph). Treatment: 16 62 Treatment: 71 Treatment: 100 Photo: Kahler CollectioTl Photo: Grahame lacksoTl Photo: Kahler Collection Photo: Kahler Collection Glollleretla Cillgulllta Photo: Wolfgang Gerlach LU-I'iol!ip/odia rhl'O!Jmllllle PIII-'Il i /1 liS 1roxi1/,\ 17 ARTOCARPUS ALTIUS BRASSICA CHlNEN 1 BRASSICA OLERACEAVAR CAPlTATA BREADFRUIT MORACEAE CHlNESE CABBAGE BRASSrCACEAE CABBAGE BRASSrCACEAE Phytophthura palmivora iHbugo cllfldilla Altemaria IJl"assicit:o/« Fruit rot White blister rust Leafspot Site of infection: Fr Site of infection: L Site of infection: L Importance of the disease: ,j,j Importance of the disease: ,j,j Importance of the disease: ,j,j Symptoms Symptoms Symptoms Spots at first brown, rapidly enlarging, up to 100 mm diam., round and covered with white fungal growth. There may be several spots on the same fruit. The lower fruit are often first to be infected. Infected fruit drop from the tree. Many other species are hosts, including black pepper, cocoa, papaya and vanilla. Raised circular, sometimes concentric, yellowgreen spots on the upper leaf surface; below, the spots rupture exposing white, powdery spore masses. The leaves may be deformed. The fungus has \iule effect on yield, but the unsightly appearance of the leaves affects market value. Other crucifers are hosts, including radish. Brown or black leaf spots, circular or irregular, sometimes concentric, and mostly between the veins. Under favourabJe conditions, the spots merge, causing the leaf to dry out and appear scorched. The fungus is common on leaves following auack by leaf scald, caused by the bacterium, Xanthomonas campestris pv. campesfris. Similar symptoms result from infection by A. brassicae, the cause of grey leaf spot, except that they are lighter in colour. They also occur on the fruits and stalks. Treatment: 18 104 Treatment: 3 Treatment: 6 , Pholo: Kohler Col/eerion Phoro: Wolfgong Gerloch Pholo: DPI Colleerion Pholo: DPI Col/ec'Iion Phoro: Wolfgong Gerloch Ph."lop!lllwra fJlIll1Iil'nm Alhugo clilldida Allel7lllr;(J h((l\'.li6('0/(( 19 BRASSICA OLERACEA VAR. CAP/TATA BRASSlCA OLERACEA VAR. CAP/TATA BRASSICA OLERACEA VAR. CAP/TATA CABBAGE BRASSICACEAE CABBAGE BRASSICACEAE CABBAGE BRASSICACEAE Perolluspura pllmsitica Tlumatephorus cucltmuis =Rhi"'.octonia so/all; Erwil1ia spp. Downy mildew Damping-off, Leaf rot, Web bIight Bacterial soft rots Site of infection: L Site of infection: L,S,R Site of infection: L,C Importance of the disease: """ Importance of the disease: "" Importance of the disease: "" Symptoms Symptoms Symptoms On the upper leaf surface, yellow to pale brown spots which deveJop rapidly under favourable, wet conditions, into large irregular patches. These turn brown and papery in dry weather. White fungal growth is abundant on the under surface of the leaf. Older leaves may have a speckled appearance. Other crucifers are hosts, including broccoli and cauliflower. A variety of symptoms, depending on time of infection. Seedlings are attacked at soil/evel, resulting in pre- and post-emergence dampingoff. Older plants may show basal rots, and Jeaves may develop large white, grey or pale brown areas of decay. The fungus forms webs which are often visible in the early morning over the areas of rot, spreading over the healthy parts of the leaf, or between 1eaves, joining them together. Many other plants are hosts, including other species of cabbage, lettuce, legumes, grasses, potato, tomato and yams. A watery soft rot at the base of the plant, followed by a wilt of the outer leaves. Rots are particularly serious after harvest, rapidly expanding, covered in bacterial slime and foulsmelling. Many other plants are hosts: carrot, celery, Chinese cabbage (lower photograph), cucumber, lettuce, potato and sweet pepper. Treatment: 20 95 Treatment: 135 Treatment: 53 Photo: Kohler Col/ection Phoro: Eric McKenzie Photo: DPI Col/eclion Photo: DPI Col/eclion Photo: Eric McKenzie photo: Wolfgang Gerlach PI!J"(II//lspor" {JIIl'o,\ific(I 711l1T1a!epflOlïI.\· C/tCll/llt! ri.\ Enl'Înia :-.pp. 21 CANNA IND/CA CANNA CAPSICUM ANNUUM SWEET PEPPER CAPSICUM ANNVUM SWEET PEPPER CANNACEAE SOLANACEAE SOLANACEAE Pll(;âllia ("alille Cerco pora capsici Cu/letotric1ll1m caps ici Rust Frog-eye leaf spot Anthracnose Site of infection: L Site of infection: L,Fr Site of infection: L,S,Fr Importance of the disease: ｾ Importance of the disease: ｾ Importance of the disease: ｾ Symptoms Symptoms Symptoms Orange powdery pustules on the lower leaf surface surrounded by a yellow halo. In severe cases of attack, the Ieaves yellow and wither prematurely and plants lose their ornamental quality. Another rust, Uredo pseudocannae. also infects this host. Pustules occur on the lower leaf surface, associated with diffuse brown blotches. Large areas of the leaf may be affected. Concentric leaf spots, white in the centre with brown margins, up to la mm diam. Often the centre of the lesion falls out. Spores form on the under surface of the leaf. Infection results in premature leaf fall. The fungus also causes a stem-end rot of the fruit. Chili is also a host. Sunken, dirty grey to greenish-black spots, merging to cover large areas of the fruit. The centres of the rot may appear papery. Red spore masses are formed on the rot, especially during wet weather, oozing from fruiting bodies which often develop in concentric circles. The disease usually occurs on the fruits when they begin to ripen. Leaves and shoots are also attacked. Chili, eggplant and tomato are also hosts. =PIIl'Cinia cmlllae Treatment: 22 118 Treatment: 25 Treatment: 34 Phoro: Kohler Col/ection Phoro: Kohler Col/ecrion PholO: Kohler Col/ecrion PholO: Kohler Collecrion Phoro: Kohler Col/arion PIICL'i /1 ill {lUI 1itu: C(!f('(Jspora capsic:i CoflelO/ridllllll ClipS ici 23 CAP lCUM ANNUUM CAPSICUM ANNUUM CAR/CA PAPAYA SWEET PEPPER SWEET PEPPER PAPAYA SOLANACEAE SOLANACEAE CARICACEAE Fu.\orillm oxy.\pmlI11l r. elldomollas ,wl(lllOcearum Curyne.\lWra ca'\. ikola Wilt BacteriaJ wilt Leafspot Site of infection: S,C,R Site of infection: S,R Site of infection: L,Fr Importance of the disease: ,j Importance of the disease: ,j,j Importance of the disease: ,j Symptoms Symptoms Symptoms Plants wilt as the fungus invades the waterconducting tissues of the root and stem. Spore masses of the fungus sometimes occur on the decayed collar region at soil level. Many other plants are host, including woody species, field crops, vegetables and ornamentals. More than one hundred specialised host-specific races exist. Leaves wilt, especially during the hottest part of the day, roots show decay and vascular tissues are brown. A cream-coloured bacterial slime oozes from the cut ends of the stems wh en these are placed in water. Plants may show a slow dieback rather than a sudden wilt of the foliage. Many other plants are hosts, including eggplant, pean ut, potato and tomato. Circular spots, up to 5 mm diam., light brown or grey, sometimes with yellow haloes. The spots appear first on the lower leaves and gradually spread upwards. As the spots age, the centres faIl out, giving a characteristic shot-hole effect. On leaf stalks, the spots are more elliptical and are covered with dark spore masses. Infection may cause premature leaf fall. Spots occasionally occur on the fruit; they are smaII, dark and sunken. On sorne hermaphrodite trees, fruits appear healthy, but the seed cavity becomes totally colonised. The fungus can damp off seedlings. The fungus is probably a secondary invader of rotting fruits of papaya and tomato. Treatment: 24 55 Treatment: 115 Treatment: 42 Pholo: Kahler Colleclion Photo: Eric A1cKenzie PhOlo: Wolfgang Gerlach Pholo: Kahler Colleclion Fusariw7I OXYIPOlïll11 Pholo: George Wall Pselll/O/llOlW l' .wlanacea rwn ory"eSj1orc/ cossiico/ll 25 CARICA PAPAYA CARICA PAPAYA CARICA PAPAYA PAPAYA CARlCACEAE PAPAYA CARICACEAE PAPAYA CARICACEAE Glomerella cil1gulata =Collelotridlllltl f,:IUl..'osporioitles Phytophthora nicoliallae \·ar. parasitica =l'hylopllthof{l pllrasilicn Spltueru'''ecajiILigillen =Oidiu11I 'p. Anthracnose Fruit rot Powdery mildew Site of infection: L,Fr Site of infection: Fr,S,R Site of infection: L,T Importance of the disease: "" Importance of the disease: " Importance of the disease: " Symptoms Symptoms Symptoms Sunken brown spots developing into large Iesions as fruits ripen. If the humidity is high, pink spore masses are produced on the corrugated surfaces of the lesions. Fruits drop prematurely, and leaves fall due to infections at the base of the petioles. On fruits, infections occur while the fruits are still green. Many other plants are hosts, including avocado, coffee, eggplant, mango, sweet pepper, tomato and yams. Water-soaked spots on mature fruits, spreading rapidly and developing a white fungal crust. Rots on the fruits may start from stem-end cankers while the fruit is still green. Infected fruits shrivel, blacken and fall. Lesions on the stems can girdle them, causing the leaves above to turn yellow and fall. Infection of the roots causes a general yellowing and collapse of the leaves. Similar symptoms occur from infection by P palmivora (Iowcr photograph). Superficial white growth of the fungus on both surfaces of young leaves, causing light yellow to green patches. The growth is often dense on the leaf stalks, and is also present on the stems and flower buds. Leaves may die prematurely. Only the Oidium or conidial form is known from the Pacifie Islands. Many species of cucurbit are hosts, as weil as legumes and members of the Compositae. Treatment: Treatment: Treatment: 26 62 105 130 Photo: Kahler Collec/ion Photo: Kahler Collec/ion Photo: Kahler Collec/ion Photo: Wolfgang Gerlach Ci/o/llerel/o cÎflgl/{a(a P!Jyro/l!Jr/wra Il;('O/;WWl! \ ar. {wrwith.'11 Sp!J(/l'rotheCl1.lu! igil1f'lI 27 CARlCA PAPAYA PAPAYA CARlCA PAPAYA PAPAYA CASUAR/NA EQUISETIFOLIA SIlE OAK, POLYNESIAN IRONWOOD CARICACEAE CARICACEAE CASUARINACEAE Papaya ringspot potyvirœ nlrnown Galludenlla app/l1nahll11 Mosaic Dieback Root and butt rot Site of infection: L,Fr Site of infection: L,S Site of infection: T,C,R Importance of the disease: ,j,j,j Importance of the disease: ,j,j,j Importance of the disease: ,j Syrnptoms Symptorns Syrnptorns Syrnptoms vary depending on the stage of infection, plant vigour, ternperature and strain of the virus. Seedlings show yellowing of the leaf veins, rnottling and distortions; leaves of older plants are rnottled and distorted; dark green streaks occur on the stems and leaf stalks; and ringspots develop on the fruits. Plants may be stunted, with fewer fruits than normal. Cucurbits are hosts to sorne strains of the virus. Bunching of inner crown leaves, rapid yellowing of the larger 1eaves, bending of the growing point, and rapid death of the entire crown within 1-4 weeks. Any fruit which is present either falls off while still green or rots. The fungus spreads in the soil, causing a root and butt rot on susceptible species. Infected trees die back and are eventually killed. Spread to neighbouring trees is by root-to-root contact. Fructifications of the fungus occur on dead and living trunks and branches of standing and fallen trees. The fungus occurs on a wide range of woody plants, causing a white heart rot. Treatment: 28 89 Treatment: 138 Treatment: 60 Photo: George Wall Photo: Kahler Col/ection Photo: Kahler ColleCiion Photo: Kahler Colle('lioll Photo: Grahame Jackson Papaya riIltLpot pOly' ｾｵｲｩ Un!l.flown Gl1IlOdermll app/lll1allllll 29 CHRYSANTHEMVM LEUCANTHEMUM CHRYSANTHEMUM CITRVLLVS LANATUS WATERMELON CITRULLUS IANATVS WATERMELON ASTERACEAE CUCURBITACEAE CUCURBITACEAE Vredo sp. Colle/olnclwlIl orbieu/are =ColLetotricJllIlIl /agel1arium Didymella bryolliae =f1scochyta cl/cumis Rust Anthracnose Gummy stem blight Site of infection: L Site of infection: L,Fr Site of infection: L,Fr Importance of the disease: ,j Importance of the disease: ,j,j,j Importance of the disease: ,j,j,j Symptams Symptoms Symptoms Spore-producing pustules on both sides of the leaves causing distortions. The leaves tllrn yellow and fall prematurel y. A disease of relatively recent occurrence in the region. On the fruits, whitish-cream sunken spots with dark brown margins, mostly on the lower parts. The spots may merge and the centres split open. Pink to orange spore masses develop on the spots in wet weather. Secondary infections may develop, causing extensive decay. On the leaves, brown spots with yellow margins, later developing into large dark brown ta black les ions which often merge. An important fungus, more common in the wet season. On Ieaves, decay begins as a rot at the margins, with water-soaked lesions spreading rapidly throughout the leaf. Lesions develop on the stems, producing a characteristic gllmmy exudate, and may girdle them, callsing premature death of the plant. Stem-end rots develop on fruits. Other cucurbits are hosts, including melon (Iower photograph). Treatment: 30 140 Treatment: 36 Treatment: 47 Photo: Kahler Collection Photo: Wolfgang Gerlach Photo: Kahler Collecrioll Photo: DPI Collection Photo: Kohler Collection Uredo sp. Col!l'lOf ric1J 1111/ orbi clIlarc Didymella fn:wmiae 31 CITRULLUS IANATUS WATERMELON GTRUS SPP. CITRUS CITRUS SPP. CITRUS CUCURBITACEAE RUTACEAE RUTACEAE Acid()IJorax avenae ub p. citmlli =PselldomOnliS pseudoalca/igenes El inoe fawcettii =Sp/wceloma fawcettii Glomerella cÏllgu/aJa =Co/fetotrichllm gloeosporioides Watermelon fruit blotch Scab Anthracnose Site of infection: L,Fr Site of infection: L,S,Fr Site of infection: S,C ImpOltance of the disease: -Y-Y Importance of the disease: -Y-Y Importance of the disease: -Y Symptoms Symptoms Symptoms Water-soaked spots on cotyledons, mature leaves and upper surface of the fruit. On the fruit, the oval to circular spots expand rapidly, covering most of the upper surface, but the infection remains superficial. Small, corky, raised, grey to Jight brown scabs, up to 1 mm diam., on both leaf surfaces, especially along the veins. They also occur on the fruit and young stems. Leaves become puckered and stunted with toro margins and may fall prematurely. Small branches may be killed. Many species of citrus are hosts, including bush Jemon, mandarin, sour orange and trifoliate orange. A disease of seedlings or grafted plants in the nursery. Brown Jesions girdle the young stems, rapidly killing the plants. Fruiting bodies occur on the lesions in large numbers. Many other plants are hosts, including avocado, coffee, eggplant, mango, papaya, sweet pepper, tomato and yams. Treatment: 32 1 Treatment: 50 Treatment: 62 Photo: Kahler Collection Photo: Kahler Colleclion Photo: George Wall Photo: Eric McKenzie Adc/(JI'oreLl: (/L'el/CIe '>ub:>p. cirrul/i lsinoe fall'ce/lii Glnmerella cingulafQ 33 PP. CITRUS SPP. CITRUS SPP. CITRUS CITRUS CITRUS CITRUS RUTACEAE RUTACEAE RUTACEAE Capllot/iulIl cilr; Penicillium digÎta/llm, P. italiclIlIl Plumerochaele salmonic%r =Corliôum sa!monicolur Sooty blotch Blue and green mouJds Pink disease Site of infection: L,S Site of infection: Fr Site of infection: S,T Importance of the disease: -J Importance of the disease: -J Importance of the disease: -J Symptoms Symptoms Symptoms Leaves are covered by a black fungal crust which develops on exudates produced from scale insect infestations. The fungus does not penetrate the Ieaf surface, but it reduces photosynthesis and, because of this, the vigour of the trees may be reduced. At first, small water-soaked areas on the fruits, enlarging rapidly to form rots several cm in diam. Spore masses develop, giving the mou Ids their characteristic colours-green CP. digitatum), and blue CP. italicum). The diseases caused by these moulds mostly occur in storage. A stem pathogen causing dieback. A pink to saimon-coloured fungal crust forms on the bark, fading to light cream with age. As the branch is girdled, the foliage wilts and dies, cracks appear in the bark and these may exude gum. Many other plants are hosts, including black pepper, cocoa, coffee, rubber, tea, and sorne forest trees. Treatment: 34 80 Treatment: 92 Treatment: 98 PholO: Kohler Col/eclioll PholO: Kohler Colleclion PholO: Kohler Colleclion PholO: Kohler Col/eclion apnodilllll cir,-i Penicil/illlil digiwfllm, P. ira/iclIJ1I Phallero('!wef WlffllO/lico!or 35 CITRUS SPP. CITRUS CITRUS SPP. CITRUS COCOS NUCIFERA COCONUT RUTACEAE RUTACEAE ARECACEAE Phytophthora nicotianae var. parasitica =PhytophtllOnl parasitica Xallflwl1WIUI!)' campe.. .tris p . ci/ri Aspergillus J1avIIS Root and collaI' rot Citrus canker Copra mould Site of infection: T,C,R Site of infection: L,Fr Site of infection: Fr Importance of the disease: ..,j..,j..,j Importance of the disease: ..,j..,j..,j Importance of the disease: ..,j Symptoms Symptoms Symptoms Dark water-soaked areas at the collaI', often with gum seeping through cracks in the bark. Beneath the bark, light brown areas of rot are present, often with clear boundaries separating diseased and healthy tissues. Infection usually progresses From discoloured and decayed roots to the trunk, although infection can also occur through wounds. As root and collaI' rots progress, leaves yellow, wither and fall, and branches die back. Initially, the symptoms may be more obvious on one side of the tree, corresponding to the part of the root system with most damage; Jater, the entire tree may wither and die. Raised corky-brown spots on the leaves, surrounded by bright yellow haloes. On the fruit, the spots often merge and develop deep cracks. Infected fruit and leaves may fall. The disease reduces the market value of the fruit. It is a disease of major quarantine impo11ance. The fungus grows on stored copra that has not been dried properly, tuming it to a yellowish green, the colour of the spores of the fungus. The mouJd produces a highly carcinogenic toxin known as aflatoxin and, because of this, affected copra cannot be used for industrial or human use. Other plants are hosts, including onion, maize and peanut. Treatment: 36 105 Treatment: 151 Treatment: 9 Ph 0/0: DPI Collec/ion Photo: Fauoro Vilson; Photo: Kahler Collection Photo: Eric McKenzie Photo: Kohler Collection J ltylophlllOm lIicorilll/(/e var, /){J"O'ilica Xalll/IOf'llOl/ll,1 C{/IJ/{lf',l/ris pV cilri AI/)(! ｲｾ i (III \ .f7111 'W' 37 cocos Nue/FERA COCOS NUelFERA COCOS NUelFERA COCONUT COCONUT COCONUT ARECACEAE ARECACEAE ARECACEAE Bipolllris im:lIrvllÛl Corliciulll penicillalum Marasmie/llls albojusClls Seedling blight Thread blight Trunk rot Site of infection: L Site of infection: L Site of infection: T Importance of the disease: ,j,j Importance of the disease: ,j Importance of the disease: ,j Symptoms Symptoms Symptoms Leaf spots at first small, oval, brown;later, enlarging to 15 mm, light brown in the middle with a broad dark margin. In severe attacks, the fronds dry out and die prematurely. Brown fungal spore masses occur on the under surfaces of the leaves. The disease can be extremely serious in coconut nurseries, but symptoms are rare on palms in the field. White fungal threads appear on the underside of the leaflets and midrib. The affected parts of the leaves become necrotic and dry. Occasionally, entire fronds are attacked, and these die and fall prematurely. The disease is more severe under shaded conditions. Associated with brown rots on the trunk of mature trees. Rots grow into the trunk from the base of old fronds. They are often extensive, with pockets of white fungal growth. Small white mushrooms grow from the decayed fronds and also on weeds and legume ground covers. The fungus has also been found on nongermi nati ng seednuts. =Drechslera inclirva/a Treatment: 38 15 Treatment: 41 Treatment: 76 Photo: Kahler Collection Photo: Kahler Collec/ion Photo: Grahame Jackson ｟Ｎｾ ,J .,, , "'\19 -, . ta. :Af· ｾｾｾ 1. •. ". Ｈｾ.... , Ml. ". ＮＧｾ ' , 4t., ＢＧＮｾ 1 _ ' . "f;, 01 . ',' '" ••• ' t\o , ".' .• , l, . ' Ｇｾｉf' ｴｾＮ , ·l'.' \' , ' . ｲＧＬＮ｜ｾｾＮ . . . \ ' . .• . . ... "r. Photo: Eric McKenzie Bipo/ar;s incllrvata Photo: Kohler Col/ection Corticiwll pelliciLllltum Photo: Grahame }achon Marasmiellll . a/hofllsCl/S 39 COCOS NUCIFERA COCOS NUC/FERA COCOS Nue/FERA COCONUT ARECACEAE COCONUT ARECACEAE COCONUT ARECACEAE Marasmiel/lls cocopltillis Marasmiellus ;lIo(/erma Pestaloliopsls pafmamm Basal rot Embryo rot, Basal shoot rot Grey leaf spot Site of infection: L,S Site of infection: L,Fr,S Site of infection: L Importance of the disease: -J-J lmpoltance of the disease: -J-J Importance of the disease: -J Symptoms Symptoms Symptoms On seedHngs, outer leaves die prematurely, as brown rots, associated with thick fungal growth, attack the leaf bases. Younger leaves are successively colonised and plants may snap at the junction of the stem and nut. Roots decay as they penetrate the leaf bases. Rots extending into the bole develop a reddish-brown margin. Where root damage is extensive, seedlings develop a little-leaf symptom when field-planted, but recover and grow normally. This disease has only been recorded from Solomon Islands. The fungus is also known from East Africa, where it has been associated with a lethal bole rot. Many grasses are hosts, including Cynodon dactylon, Echinochloa colona and Eleusine indica. The fungus colonises the shoot as seed-nuts germinate. Early infection destroys the embryo, leading to invasion of the nut cavity and the development of a pinkish-white fungal growth over the endosperm. Secondary rots which are soft and foulsmelling may develop. Where shoots survive early infection, brown rots may develop at the base of the leaves and stems, and these are often associated with large amounts of white fungal growth. Usually, seedlings outgrow this attack, but growth may be slow, or the plants may be killed if growing conditions are poor. Mushrooms form on the nuts and at the base of the seedlings. Banana (stem rot), maize and rice (root rot and wilt) and taro (shallow corm rot) are also hosts. Leaf spots oval, up to 15 mm long, grey with dark brown borders, and sometimes with yellow haloes. Spots may merge. Fungal fruiting structures occur as black dots within the spots, especially on the upper leaf surfaces. Other palms are hosts, including betel nut and oil palm. Treatment: 40 77 Treatment: 78 Treatment: 96 PholO: Grahame Jackson PholO: Eric McKenzie Photo: Eric McKenzie Photo: Grahame Jackson PholO: Kahler Collection PholO: Kohler Collection Marasmiellll.l' (,{)(,o/JhiIUS Marasmiellll.\· i/lodermo Pes(a{Olwp:"is pallllll/ï/llJ 41 COCOS VUCIFERA COCOS NUC/FERA COCOS !VUCIFERA COCONUT ARECACEAE COCONUT ARECACEAE COCONUT ARECACEAE Phytophthora Izel/eae Phytophthora palTllù/ora PscudoepicoccUnl cocos Bud and nut rot Bud rot Brown leaf spot Site of infection: L,Fr Site of infection: L Site of infection: L Importance of the disease: './ Importance of the disease: './'./ ImpOitance of the disease: './ Symptams Symptoms Symptoms A lethal wet bud rot of mature palms. Symptoms on mature palms are similar to those caused by P. palmivora. Nuts are also auacked; if infections occur at the point of auachmentto the flower stalk it may lead ta premature nutfall. Infections at the base of the youngest leaves, killing them and spreading outwards, causing older leaves to wilt. Seedlings commonly die from the attack, but sorne may recover, producing a liule-Ieaf symptom. On mature pal ms, the disease often follows cyclone damage. Early symptoms are sometimes difficult to detect and only apparent when bud rot has caused almost complete destruction of the shoot. Many othcr species are hosts, including black pepper, breadfruit, cocoa, papaya and vanilla. Oval spots, up to 10 mm Jong and 4 mm wide, usually smaller, sometimes with pale centres and darker margins on upper Jeaf surfaces. Black powdery spore masses develop on the spots on the lower leaf surface. Betel nut and oil palm are also hosts. Treatment Treatment Treatment 42 104 104 113 Pholo: Kohler Colleclion Pholo: Kohler Co!lec/ion Photo: Eric McKenzie Pholo: Kohler Collection Phytoflhll/(Jrl( 1(('\'('(/(' Photo: Kohler Co!leclion Pltv/oplttllOru pall/livora P.I'l'lIdo('piCO('ClIlII CO"OS 43 COCOS NUC/FERA COCOS NUC/FERA COFFEA ARAB/CA & C. CANEPHORA COCONUT COCONUT COFFEE ARECACEAE ARECACEAE RUBIACEAE oconut foLiar deC3} nan."'irus oconut ｴｩｭｬｄｾ｡ｪ vil" id Cerco.\porll co..ffeicola Coconut foliar decay Tinangaja Brown-eye leaf spot Site of infection: L Site of infection: L,FI,Fr Site of infection: L,Fr Importance of the disease: .,j.,j.,j Importance of the disease: .,j.,j.,j Importance of the disease: .,j Symptoms Symptoms Symptoms At first, yellowing on severalleaflets on fronds five to eleven from the crown, followed by more extensive yellowing and the appearance of areas of rot in the petiole. Fronds may break and hang down through the canopy. Other fronds die and break as they reach the same position in the crown. At this stage, young and older leaves remain green. Further development of symptoms depends on variety. In sorne cases, the symptoms disappear, whereas in susccptible palms the crown dies six months to two years after symptoms first appear. The disease is known only from Vanuatu. Yellow spots on the leaves and the production of small, scarified, elongated nuts lacking kernels. Inflorescences become necrotic, nut production declines and then ceases, frond production slows, and a general yellowing appears, followed by death of the crown. The viroid is related to cadang-cadang viroid, the cause of a JethaJ disease of coconuts in the Philippines. Coconut tinangaja viroid is known only from Guam. Circular spots, up to 30 mm diam., but mostly 510 mm, like a bird's eye: bright grey centres, dark brown borders with yellow haloes. Spots are most obvious on the upper Ieaf surface. Dark spore masses occur on the grey centres. Severe attacks on seedlings cause leaf-fall and sJow growth. It is less important on mature plants. On berries, spots are dark grey or brown, oval, sunken and usually Jess than 5 mm diam. Affected berries turn black, shrink and fall. Unshaded trees are more likely to be attacked, especially jf nutrition is poor. Treatment: 44 31 Treatment: 32 Treatment: 26 PholO: Grahame Jackson Photo: Grahame Jackson Photo: Kohler Collectioll Photo: John Rondies Photo: Grahame Jockson Photo: Kohler Collection Cocnnul foliar dccay l1anavirus OCOl1ul timmgaja viroid CerCOI"/70m ('ojJ't!icoln 45 COFFEA ARABICA & C. CANEPHORA COFFEA ARABICA & C. CANEPHORA COFFEA ARABICA & C. CANEPHORA COFFEE COFFEE COFFEE RUBIACEAE RUBIACEAE RUBIACEAE G/omere/la cillgu/l1ta Hemileia l'lIstalrix Fusarilll11 oXYSPo/'U11l f. sp. coIreae = o/letotrichum 4oem'Pori()ide.\' Wilt Anthracnose Rust Site of infection: T,C,R Site of infection: L,Fr Site of infection: L Importance of the disease: -V Importance of the disease: -V Importance of the disease: -V-V-V Symptoms Symptoms Symptoms A soil fungus causing a serious wilt of young plants. Brown rots occur at the collar, which sometimes becomes covered with fungal mycelium. The plants wilt, gradually dry out and die. Anthracnose of the foliage and berries is more serious on Arabica varieties weakened by rust attack. The foliage blackens and dries, brown spots on the berries become darker and the berries become mummified and fall. In extreme cases, the trees are defoliated. On Robusta, damage from anthracnose sometimes occurs on coffee exposed to heavy rains. Many other plants are hosts, including avocado, eggplant, mango, papaya, sweet pepper, tomato and yams. Yellow-orange leaf spots, up to 15 mm diam., circular, forming powdery blotches on the underside of leaves and yellowing on upper surfaces. Later, the centres of the blotches die and turn brown, and on the upper surface brown spots develop with yellow halos. Blotches may merge and coyer the entire leaf blade. In severely affected plants, leaves fall and branches die back. Plants weakened by nlst are also more susceptible to attack by anthracnose, which is not normally the cause of serious disease. Treatment: 46 57 Treatment: 62 Treatment: 68 Photo: Kahler Colleclioll Pholo: Kahler Colleclion Pholo: Kahler Colleclion Photo: Kahler Collecrion Photo: Kahler Colleclion /I.\'Or;11I1I oxysporwn f. Sp. cof{eae Glo/TIl!l'el/li cingillulll Ile/llileiu 1'11S!lIIrÜ 47 COFFRA ARABICA & C. CANEPHORA COFFEA ARABICA & C. CAN PHORA COFFEA ARABICA & C. CANEPHORA COFFEE COFFEE COFFEE RUBIACEAE RUBlACEAE RUBIACEAE Pellù:u/al"Ïa koleroga =CorlÎl:iu11l kO/erogli P/UlIlerocllOele sa/monic%r =Corticiul1l '(l!mollÎl'olor P/wllinus lamaensis Thread blight Pink disease Brown root and collar rot Site of infection: L Site of infection: L,S,T Site of infection: L,T Importance of the disease: -V Importance of the disease: -V-V Importance of the disease: -V-V Symptoms Symptoms Symptoms Mats and thread-Iike fungal growth on the branches, spreading over the under surfaces of leaves. At first, the foUage appears slightly grey and dry. Later, the leaves blacken and fall. ln severe cases, the dead leaves become detached from the branches, but are held in place by threads of the fungus. Branches may die back. Other plants are hosts, including citrus, cocoa and woody plants. A stem pathogen causing dieback. The fungus forms a pinkish-white crust on the surface of the bark. Later, this becomes light cream, the bark develops cracks, and the foliage dries out and dies. ln some countries, the disease is more common on Robusta coffee. Many other plants are hosts, including black pepper, citrus, cocoa, rubber, tea, and some Forest trees. A sudden yellowing of aU or part of the foUage, followed by withering of the leaves and defoliation. At the same time, a tough brown crust grows up the tree from the base of the trunk. Beneath the crust, the wood is discoloured, later becoming dry and honeycombed. Often, several adjacent trees are affected as the fungus spreads through the soil by root-to-root contact. The spore-producing bracket or fruit body is not commonly found, as it does not develop until some years after the death of the tree. Treatment: 48 91 Treatment: 98 Treatment: 99 Photo: Eric MeKenzie Photo: Kahler Col/ee/ion Photo: Kahler Col/ee/ion Photo: Kahler Col/eCiion Photo: Kahler Collection Pe/fiel//aria koferoga P//(/ Ile roc /wc le .1'(// mO/l i< ·ofor Plleflil/us /amaensi 49 COFFEA ARABICA & C. CANEPHORA COLOCASIA ESCULENTA COWCASJA ESCULENTA COFFEE RUBIACEAE TARO ARACEAE TARO ARACEAE Verticillium hemileiae Cllldosporium c%ca ·ille Marasmiel/us stellophyllus Rust hyperparasite Ghost spot Corm and leaf rot Site of infection: L Site of infection: L Site of infection: L,S,R Importance of the disease: Nil Importance of the disease: ,j Importance of the disease: ,j Symptoms Symptoms Symptoms Pustules of the coffee rust pathogen become covered in a dense white growth of the fungus, which lives on the spores. Reddish brown, circular or irregular blotches often with a yellow halo, up to 15 mm diam., on older leaves. Spots are smaller when there are many on the same leaf. Usually, they are less evident on the opposite leaf surface. Spots at the border of the leaves may merge, causing the margins to turn brown and dry out. Leaves collapse due to the development of large brown rots at the base of the plant associated with thick white fungal growth. The leaves are often stuck together by the fungal threads. Mushrooms form in large numbers on the withered leaves at soillevel. Shallow rots occur in the corms and the roots are decayed. Treatment: 50 Treatment: 29 Treatment: 78 Phoro: Kahler Collection Photo: Grahame Jackson Photo: Kahler Collectioll Photo: Kahler Colleetioll Photo: Wolfgang Gerlach Photo: Kahler Collec1iol1 Verlicillill/Il hemileiae CladrHJ10rillm colocasiae Ma ra. lIliellllS sfenophylliis 51 COLOCA51A ESCULENTA COLOCASIA ESCULENTA COLOCA5/A ESCULENTA TARO TARO TARO ARACEAE ARACEAE ARACEAE PllOma spp. PllyLo{J/rtllOra co!ocllsiae Orange ghost spot Leafspot Leafblight Site of infection: L Site of infection: L Site of infection: L,S N ･Ｈｾｩｯｨ IlstOIlia co!ocasiae Importance of the disease: .y Importance of the disease: .y Importance of the disease: .y.y.y Symptoms Symptoms Symptoms Yellow-brown, round or irregular spots, up to 15 mm diam., on both sides of the leaf, sometimes with a brown margin and yellow halo, becoming darker as the spore masses develop. The spots are smaller when large numbers develop on the same leaf. Oval leaf spots, up to 30 mm long, brown with a yellow border, sometimes merging. The centre of the spots characteristically tears and may fall out to give a shot-hole effect. The disease is widespread in the Pacifie, where it has often been identified as a species of Phyllosticta. It has occasionally been confused with taro leaf blight caused by Phytophthora colocasiae. At first, small circular spots, brown on the upper kaf surface, water-soaked beJow, rapidly enlarging, becoming irregular in shape, dark brown, zoned, with yellow margins and containing characteristic yeUowish to red droplets drying as hard pellets. Spots often start on the older leaves, usually at the edges where water coJlects. White fungal spore-producing areas occur at the margins of the spots. Typically, the leaves collapse in 10-20 days. Petiole infections are less common, but occur on susceptible varieties. The fungus is also responsi ble for a post-harvest corm rot. Giant taro, Alocasia macrorrhizos, is also a host (Iower photograph). Treatment: 52 86 Treatment: 101 Treatment: 103 Photo: Grahame Jackson Photo:\Vo/jgang Gerlach Photo: Graharne Jackson Pholo: Grahame Jackson Photo: Eric McKenzie Nl:!ojol/llSfol/ia CO/OCt/Sille Plu)//w Spp PhvtophtlWrl/ (.'%casillt! 53 COWCASIA E CULENTA COLOCASlA ESCULENTA COWCASIA ESCULENTA TARO TARO TARO ARACEAE ARACEAE ARACEAE Pseudocercospora c%ca'îiae Pyt"ill11l pp. 1J;rschm{(lllliella miticausa Leafhlotch Corm rot Root and corm rot Site of infection: L Site of infection: S,R Site of infection: S,R Importance of the disease: -J Importance of the disease: -J-J Importance of the disease: -J-J Symptoms Symptoms Symptoms Pale, indistinct yellow-red patches, up to 15 mm diam., on the upper leaf surface; light brown spots with black fungal growth on the 10wer surface. Symptoms vary, depending on the age of the plants when attacked and the species of Pythium involved. Roots and basal parts of young plants may be attacked before they develop leaves, and they die or remain stunted. On mature plants, the first symptom is often a rapid collapse and withering of the outer leaves due to a 10ss of lateral and feeder roots. The colour of those remaining is an unhealthy greyish blue-green, often with pale yellow margins. Rots caused by Pythium fungi may occur in the corms. Later, corms may be invaded by Erwinia bacteria which produce a foul-smelling soft rot. P spLendens is the cause of a post-harvest corm rot. Internally, corms show brown areas of dry rot extending in narrow bands upwards from the base. At first, the rots are confined to the vascular tissues, but later they spread to adjacent areas. Healthy tissue alongside the rots are red and corms have the appearance of raw meathence the pidgin na me of the disease in Solomon Islands of 'mitimiti'. The rots are often not apparent until the taro are harvested, although sometimes wetland taro wilt and the plants become stunted. Treatment: 54 111 Treatment: 120 Treatment: 69 Photo: Grahame Jackson Photo: Grahame Jackson Photo: Kahler Col/ection Photo: Grahame Jacksoll Photo: Wolfgollg Gerlach PS(!lIdocerc() pora (,%('lIsial! Pyf!liWI1 Spp. lIirschnw/ll/Îel/a mif; 'a/lsa 55 COLOCASIA ESCULENTA COLOCASIA ESCULENTA COWCASIA ESCULENTA TARO TARO TARO ARACEAE ARACEAE ARACEAE ==CBDV Coloca. iu bohonc disease (?) rhahdovirus and da, heen ba 'illiform badnavi 15 olocasia hohonc disea"e (?) rhahdovinls = BDV (Fiji strain) Bobone Alomae Unnamed Site of infection: L Site of infection: L Site of infection: L Importance of the disease: -V-V Importance of the disease: -V-V Importance of the disease: -V Symptoms Symptoms Symptoms Leaves are puckered, distorted, brittle and thickened, but remain green. Symptoms appear after planting or at any other time during the growing cycle. After three or four affected leaves are produced, plants recover by producing apparently healthy leaves. Sorne plants develop symptoms twice during the same crop. Initially, symptoms are similar to plants with bobone. Leaves are short, thick, often with gaUs, but often remain green. The next leaves to be produced are yellow with prominent veins, and they remain roUed and stunted. Leaf production ceases and the plants rot and die. Alomae has been recorded from Solomon Islands and Papua New Guinea. Giant taro, Alocasia macrorrhizos, is also a host. Leaf veins, especially those at the margins, become yellow. Usually, only two or three leaves show symptoms before apparently healthy leaves are produced. OccasionalJy, extensive areas of yeUowing occur between the veins on leaves which are stunted and distorted. Initially, these plants may look similar to those with alomae, but they recover from the disease and do not die. ｡ｩＧｾｌｻ｣ＩｴｉＨｃ bohone disca"ic (?) rhabdovirus Treatment: 56 37 en Treatment: 38 Treatment: 39 %CllsiCl PholO: Grahame Jackson PholO: Grahame Jackson Photo: Grahame Jackson Photo: Bill Zel/ler Photo: Grahame Jackson PholO: Grahame Jackson bl)b ne disease ('1) rhabdovirus CBDV & ùu."heen bacilliform (?) badnaviru. CSDV (Fiji :train) 57 COLOCASIA ESCULENTA COWCASIA ESCULENTA CORDIA ALL/ODORA TARO ARACEAE TARO ARACEAE LAUREL Dasheco mo 'aie pot. "lrUS V Da...hren mo 'aie ｾｬｲｩｶｹｴｏｰ =D (5' ere strain) Pltdlillus lIoxiu. =() Dasheen mosaic Dasheen mosaic Brown root and collar rot Site of infection: L Site of infection: L Site of infection: T,R Importance of the disease: -V Importance of the disease: -V-V Importance of the disease: -V-V-V Symptoms Symptoms Symptoms Pale yellow to green patches on the leaves, characteristically as feather-like patterns along the veins, especially near the leaf margins. Occasionally, yellow and green patterns occur over the entire leaf surface, which may appear narrow, with a distorted margin. Usually, two or three leaves show symptoms and then apparently healthy leaves are produced. Giant taro, Xanthosoma and giant swamp taro, as weil as many ornamental species, including Caladium, Dieffenbachia and Philodendron, are hosts. Pale green to yellow patterns on small, stunted and severely distorted leaves. Sorne leaves are reduced to strap-like structures without lobes, or are entirely absent. Pigmented varieties show a loss of colour. Plants fail to recover from infection, in contrast to those with the common strain of dasheen mosaic virus, but they do not die. Corms are smaU. This disease has been recorded only from French Polynesia. Symptoms depend on the age of the trees when they are attacked. Young trees frequently die rapidly after infection; those that are older, and thus larger, may remain partially affected for years. Basal heart rot may develop, making them more susceptible to windthrow. Invariably, a thick, dark fungal growth containing soil particles covers the roots. This may spread upwards around the collar and trunk forming a prominent hrown or black 'stocking'. Bracketlike fruit bodies sometimes form on affected logs and stumps, especially those of indigenous trees. Many other forest and plantation species are hosts, including Swietenia macrophylla, Tectona grandis, cocoa and coffee. Treatment: 58 45 Treatment: BORAGINACEAE 46 Treatment: 100 ｄ￩ｉＮＬｨｴＺｾｮ I11Il'\UÎc Photo: Grahame Jackson Photo: Leon Mu Photo: Mike Ivory Photo: Cra/wllle Jackson Photo: Leon Mu Photo: Mike Ivory potyviru ... Dasheeu musaÏl' pOlyvirus Ｚｮ･Ｇ｜ｴｾＨＩｮｩ｡ｲｬｾ P//('!Ii/lll.\ 1/O.\ÏI/.\ 59 CUCUMI ' MELO CUCUMIS SA TI VUS CUCUMIS SA Tl VUS MELON CUCURBITACEAE CUCUMBER CUCUMBER CUCURBITACEAE CUCURBITACEAE o/letolridllll1l orbiclIulre =ColletotridllllTl lagenarium Coryllespora cassii{'()la Didymella bryolliae Anthracnose Leafspot Gummy stem blight Site of infection: L,Fr,S Site of infection: L Site of infection: L Importance of the disease: ,f,f Importance of the disease: Symptoms Symptoms Symptoms On the leaves, small, brown, circular spots with a yeJlow halo; later, enlarging, becoming round to oval, dark brown to black, often centred on the veins. Spots also occur on the vines. On the fruit, circular, pale brown, sunken spots with raised margins, often more corn mon on the lower half of the fruit. Spots up to 30 mm diam., but often merging to cover extensive areas of the fruit. Pink to orange spore masses occur on the spots during wet weather. Secondary rot-causing organisms may completely destroy the fruit. Many other species of cucurbits are hosts, including cucumber and watermelon. Numerous small, round, up to 4 mm diam., or irregular-shaped, cream-coloured spots. The leaves dry out and fall prematurely. The fungus is probably a secondary invader of rotting fruits of papaya and tomato. Marginalleaf rots, expanding rapidly and causing large areas of decay resulting in premature defoliation. Numerous black sporecontaining structures develop on the periphery of the lesions. Treatment: 60 36 =ftscochyta CIIClllllis Treatment: ·N 42 Importance of the disease: ,f,f,f Treatment: 47 Photo: Grahame Jackson Photo: Grahame Jackson Pl/olO: Eric McKenzie Phoro: Gral1ame Jackso/1 Pholo' Kahler Col/eCiion olletorrf( hum orhiclI/(lre CorYflcspora ('(ls\ii<:o/a Dit/VII/fI/a bryofl/l/f' 61 CUCUMIS ATlVUS CUCUMIS SATIVUS CUCUMIS SATlVUS CUCUMBER CUCURBITACEAE CUCUMBER CUCURBITACEAE CUCUMBER CUCURBlTACEAE P"eudopU01lOspora cubells;s Pyt!l;lll1l spp. Sphaerullteca ji,li/.rillèll =Vitiiu", sp. Downy mildew Cottony leak Powdery mildew Site of infection: L Site of infection: Fr Site of infection: L,S,Fr Importance of the disease: -V Importance of the disease: -V-V Symptoms Symptoms Symptoms Angular to round yellow areas occur on the upper leaf surface, later merging and becoming brown. In wet weather, downy growth develops on the under surface of the leaves, and they dry out and die. Fruits are not directly affected, but those that form are small and do not ripen properly. Many other cucurbits are hosts, including melon, pumpkin, squash and watermelon. Watery soft rot with masses of white cottony fungal growth on fruit in contact with the soil. The disease is commonly caused by P. aphanidermatum and P. deliense. The fungi also cause a pre- and post-emergence damping-off in seedlings of many plant species. P. aphanidermatum causes a corm rot of taro and cottony leak on beans (lower photograph). White powdery growth on leaves, stalks and flowers. At first, small, circular, white powdery patches, mostly on the lower surface. Affected Ieaves gradually turn yeJlow, then brown, dry out and die. Only the Oidium or conidial form is known from the Pacifie Islands. Many other species of cucurbits are hosts, including melon (Iower photograph), pumpkin, squash and zucchini, as weil as legumes and members of the Asteraceae. Importance of the disease: Treatment: 62 -v+J 116 Treatment: 121 Treatment: 130 P.Il!l/(/()p('mllt),lporo Photo: DPI Collection Pholo: Wolfgang Gerlach Photo: Graharne Jackson Photo: DPI Collection Photo: DPI Colleclion Pholo: Kahler Colleclion cuber/sis Pl'lhilllll "pp. Splll1 c> /'Ot IU'('(Iji, 1ig illl!L! 63 CUCURB/TA PEPO CYRTOSPERMA CHAMISSONIS DA UCU ' CARDTA ZUCCHINI CUCURBITACEAE GIANT SWAMP TARO ARACEAE CARROT APIACEAE Zucchini yeUow mo 'aie potyvirus RlldopllOlli !\Îmilis Allemaria dalicÏ Zucchini yellow mosaic Corm rot Blight Site of infection: L,Fr Site of infection: S,R Site of infection: L Importance of the disease: ...J-,N Importance of the disease: ...J...J Importance of the disease: ...J...J Symptoms Symptoms Severe yellow-green patterns, usually with distortions and blisters on the leaves and fruits. Often the plants fail to set fruit, and those that form are small. Other cucurbits are also hosts: pumpkin (lumps and mottle patterns on the fruits and mosaics on the leaves-Iower photograph); squash (fruits small in size with yellow blotches and rings); and watermelon. Treatment: 64 155 Extemally, corms look as if they have been bored by insects with 5-20 mm diam. ho les, 1020 mm deep. Beneath, the tissues show a brown superficial rot, occasionally extending as narrow channels deep into the centre of the corm. Often, roots show considerable decay, but generally the leaves appear healthy. Many crops are hosts, including banana, bele, ginger, legumes, maize and yams. Treatment: 123 At first, dark grey to brown spots, angular, with yellow margins on Ieaves and petioles. Older leaves are attacked initially, but spores from these spread to younger foliage which rapidly blackens, withers and dies. Another disease, caused by Cercospora carotae, produces similar symptoms: circulaI' tan or grey spots on the leaves and leaf stalks, which merge and develop into a blight during humid weather. Treatment: 7 Photo: Kohler Col/ec/ion Photo: Grahame Jackson Photo: Kohler Col/ec/ion Photo: Grahame Jackson Photo: DPI Collection PholO: DPI Col/ec/ion PhOlO: Semis; Pane ZUc.:ChlOi yell lW ｬＱｯｾ｡ｩ｣ poty Inl.' Radopl1o/w simili.1 ,\I{l'maria dauci 65 DAUCUS CAROTA DA ueus CAROTA DJOSCOREA ALATA CARROT CARROT GREATERYAM APIACEAE APIACEAE DIOSCOREACEAE ,1l1enwria mdicilla =Slemp/ly/ium radicÙIlI11l ;ltite/ifl ｲｯｬｪＮｾｩ =Sclerotiul1l rolf\''-; G/omerella âllgll/ata =Col/etotricJllIlll g/oCo.\1UJriowcs Root rot Basal rot Anthracnose Site of infection: R Site of infection: C,R Site of infection: L,S Importance of the disease: '1/ Importance of the disease: '1/'1/ Importance of the disease: '1/'1/'1/ Symptoms Symptoms Symptoms Slightly sunken necrotic spots over the surface of the root, covered in a rust-brown matting of fungal growth in which spores develop. As the decay spreads, the areas of rot deepen and the roots become unfit for consumption. At first, spreading white fans of funga1 growth over the root and base of the leaves; 1ater, characteristic small white to light brown sclerotia, 1-2 mm diam., form within the growth, at or immediately below soillevel. Plants invariably die from infection. A wide range of cultivated plants and weeds are hosts, incJuding beans, cucurbits, sweet pepper, sweet potato, taro and tomato. Small brown spots, sorne with yellow haloes on the young leaves, enlarging as the leaves expand. Sometimes the spots merge, forming large irregular blotches. Infected leaves fall prematurely. Mature leaves show brown pinpoint infections which do not penetrate to the other leaf surface. Pink to orange spore masses occur on the spots during wet weather. During long periods of rain, and on susceptible varieties, leaves and vines blacken rapidly and dico New shoots may develop and plants may produce several small tubers as a consequence. In the Caribbean, the fungus has been reported to cause a shallow tuber rot. Many other plants are hosts, including avocado, coffee, eggp1ant, mango, papaya, sweet pepper and tomato. Treatment: 66 7 Treatment: 11 Treatment: 62 PholO: Kohler Collection Photo: Gr(lharne Jack.w/1 Photo: Ko"'er Collectioll Photo: Grahame Jackson PhOIO: Kohler ColleClioll Allenwl'Îo radie;'/([ AlhelilJ mIMi G/ol7lere/la ('il/gll/mll 67 DIOSCOREA SPP. DJOSCOREA PP. DI0SCOREA SPP. YAMS DIOSCOREACEAE YAMS DIOSCOREACEAE YAMS DIOSCOREACEAE Goplallu Ｇｾｩｬ｡ｲｴｳＨ Goplll1W dioscorelle Guigllflrdia dioscnreae =Phyllosticla dioscurelle Rust Rust Leafspot Site of infection: L Site of infection: L Site of infection: L Importance of the disease: -V Impo11ance of the disease: -V Importance of the disease: -V Symptoms Symptoms Symptoms Pale yellow pustules, mostly on the under surface of the leaf in groups, 2-4 mm diam. Pale brown, circular spots with pale green-yellow haloes occur on the upper leaf surface. Symptoms are similar to those of G. Qustralis. Yellow pustules occur on both leaf surfaces, but especially on the upper surface, often in groups. Leaf spots circular or irregular, up to 10 mm diam., light brown with a dark brown or black border and yellow ha,lo. The black fruiting bodies of the fllnglls are lIsually scattered in the centre of the spots. Treatment: 68 64 Treatment: 65 Treatment: 66 Q Photo: Eric McKenzie CO!ihm(/ ail Ilrali,\ Photo: Eric McKenzie COpllll/li dim 'orelle Photo: Kahler Collection GlliXl/urdiu dioscor(!lIl! 69 x ANANASSA DIOSCOREA SPP. ELAEIS GUINEENSl FRAGARIA YAMS OILPALM STRAWBERRY DIOSCOREACEAE ARECACEAE ROSACEAE Protylellt:JllIs ('offelle Cadang-mdang-like virnid RllizopliS stolollifera Thber rot Orange spotting Soft rot or leak Site of infection: R Site of infection: L Site of infection: Fr Importance of the disease: ...J...J Importance of the disease: ...J Importance of the disease: ...J Symptoms Symptoms Symptoms Dark brown dry rots, 5-20 mm deep, beneath the tuber skin. Extemally, the skin may flake and crack, showing the rot beneath. In heavy infestations, the rots may coyer the entire tuber. The disease can be particularly severe during storage, resulting in the loss of planting material for next season's crop. Sometimes, other microorganisms invade the damaged areas and assist in the destruction. Numerous bright orange spots, 2-3 mm diam., on ail except the youngest three to four fronds. Palms are stunted, and bunches and nuts are reduced in size and number. Previously this condition was known as genetic orange spotting and was not considered to be a disease. Rapidly developing soft wet rot covered by cottony white fungal growth. As the rot progresses, small white, stalked, fruiting bodies are produced, becoming black as they mature. Enzymes produced by the fungus break down the cells, and the contents reJeased often have a fermented or acidic smell, hence the other name of 'Ieak' for the disease. The disease is important only after harvest, and affects a wide range of soft fruit in transit and storage. Root crops are also attacked. Treatment: 70 109 Treatment: 20 Treatment: 124 Photo: Johfl Rafldles Phmo: John Bridge Phmo: Kahler Col/eCiion Photo: Johfl Rafldles Pra/del/dw . ('ofJeW! Cauang-cadang-like viroid Rhi:ojJlIS .\f%l1ij'cra 71 FRAGAR1A x ANANASSA GERBERA SP. GLADIOLUS SP. STRAWBERRY GERBERA GLADIOLUS ROSACEAE ASTERACEAE IRIDACEAE Sphaerotheca maCll/ar;. Fll.'wrium oxyspOrtl11l r. sp. gerberae 'usariulIl oxyspomlll f. p. g/adioli =Oid;um sp. Powdery mildew Fusarium wilt Wilt Site of infection: L,FI,Fr Site of infection: S,R Site of infection: S,R Importance of the disease: -,j-,j Importance of thee disease: -,j ImpOltance of the disease: -,j Symptoms Symptoms Symptoms White patches of fungal growth develop, sometimes covering the entire leaf, causing it to roll and curl upwards. Purple or reddish blotches may also occur. On the fruit, a white powdery covering develops, the surface of the fruit hardens, and cracks appear. Infection of the vascular tissues of the roots and stem base, leading to a wilt and eventual death of the foliage. Infection of the roots leads to a rot of the corm and eventually a wilt and death of the plant. Treatment: 72 131 Treatment: 59 Treatment: 55 Photo: DPI Collee/ion Photo: Kahler Collee/ion Photo: Kahler Colleetion Photo: Kohler Collection Sphaemtheca maclIloris Photo: Kahler Collection FlI.mrilllll O.t)'SpOrLlIll f. Sp. gerherae FlIsariulIl OXY\jWIïI/II r. Sp. glatlioli 73 GLYCINE MAX HEUANTHU ANNUUS HIBI CU SOYBEAN FABACEAE SUNFLOWER ASTERACEAE HIBISCUS MALVACEAE Sc/t'roli"ia sch.'rofial'llf1l Sclemli"ia .1iu'ke/illllll Rll/lIllOplwr(l ji,ngo \'il Stem rot Stem rot Plant parasite Site of infections: S,R Site of infection: S,FI,Fr Site of infection: R Importance of the disease: ...j...j...j Importance of the disease: ...j Importance of the disease: ...j Symptoms Symptoms Symptoms Small, water-soaked, pale or dark brown spots on the stems and branches, sometimes girdling them and causing the foliage to wilt and die. Under high humidity, the roots are covered with thick mats of the fungus within which numerous sclerotia develop. These, the resting structures of the fungus, are at first white, 2- JO mm long, and later black and hard. Sclerotia occur both inside and outside the stem. This is a seriolls disease of soybean which is capable of destroying entire plantations. It is a disease of importance in temperate c1imates. The fllngus can survive for a long time in the soil and has a wide host range, including beans, cabbages, carro t, celery, lettuce, potato and tomato. A rot of the top of the stem which causes the plant to droop. Internally, the vascular tissues are completely destroyed by the fungus. The fJowers and seeds may also be attacked. Large, black, irregular-shaped sclerotia develop on the areas of rot. A parastic plant that lives on the roots of other plants. Treatment: 74 127 Treatment: 127 Treatment: ROSA-SINENS/S 12 Photo: Kohler Collection Photo: Kahler Collrctio/l Photo: Kahler Collection PhOIO: Kahler Collection ｾＧ､ｬｭｩｬ ""(em/in/'1I1l1 ｾＧ､ｬｭｩＨＯ /il('/"'elial7u 8(1 (lI1/(J/I!/()l'II / III/go l'fi 75 HORDEUM VULGARE fPOMOEA AQUATTCA IPOMOEA AQUATICA BARLEY KANGKONG, WATER SPINACH KANGKONG, WATER SPINACH POACEAE CONVOLVULACEAE CONVOLVULACEAE PyreTwplwra gramilll'a =Drecltslera r"mn;/lea Albugo ;p()nloeae.aqlllllicae Cerc(},\pora ipolJloeae Leaf stripe White rust, White blister Leafspot Site of infection: L Site of infection: L,S,FI Site of infection: L Importance of the disease: +-1 Importance of the disease: -J Importance of the disease: -J Symptoms Symptoms Symptoms At first, small yellow spots on seedling Ieaves resulting from seedborne infections; later, on mature leaves, the spots develop into long yellow to light brown stripes with brown margins and pale yellow centres. The leaves dry out and die prematurely. Severe seedling infection ma)' result in the death of plants or stunting. White or pale yellow blisters on the underside of the Ieaves, and on the stems and flowers. Often the blisters join together. Sweet potato and ornamental species of Convolvulaceae are also hosts. CirculaI' to irregular leaf spots, up to 5 mm diam., red-brown on the upper surface, grey on the lower surface, with yellow haloes. The centres of the spots sometimes fall out. Sweet potato and sorne ornamental Convolvulaceae are hosts. Treatment: 76 122 Treatrnent: 4 Treatment: 27 Pholo: Kohler Col/ecliOlI Pyrel1op!1orcJ gramil/l'a Pholo: Eric McKelJzie AlbI/go ipoll1oeae-a{Jlloricae PhoJO: Eric McKenz.ie CercosporQ ip(Jl/lo€lIe 77 IPOMOEA BATA]; S SWEET POTATO [PON/OEA BATATAS SWEET POTATO [POMOEA BATATAS SWEET POTATO CONVOLVULACEAE CONVOLVULACEAE CONVOLVULACEAE EL'Iinoe batata, ｲ･｣ｯ､ｬ･ｩＧｾｬ PhytopLamla =Mycopla.·ma-like organism a para timorellsis Scab Leafspot Little-Ieaf, Witches' broom disease Site of infection: L,S Site of infection: L Site of infection: L,S,R Importance of the disease: 'Ii'li'li Importance of the disease: 'Ii Importance of the disease: 'Ii'li'li Symptoms Symptoms Symptoms SmaJi brown, round to oval 'scabby' leaf spots, 3 mm long and 1 mm wide, mostly along the midrib and veins, becoming lighter with age. Often the scabs join together, forming lesions several cm long. Pinpoint spots occur on the 1eaf blades between the veins. On the petioles, spots are 1-5 mm long, and slightly sunken. In severe attacks, leaf blades are small, curled, with deeply tom edges, and petioles are short, twisted and erect. Leaf spots brown, circular to irregular on the upper surface, sometimes with a light brown centre. On the lower surface, the spots are illdefined, brown or grey. Usually, the spots occur on mature leaves. Other Ipomoea species are hosts. At first, yellowing of veins on leaves which otherwise appear normal. Leaves become progressively smaller until they are about an eighth the size of those that are healthy. They become yeIJow, occasionally roJied upwards at the margins, puckered, and in some varieties more rounded than normal. Diseased stems are short, with as little as 10 mm between leaves, and erect. Side shoots develop and plants become bushy. Tubers, if produced, are pencilthin. Diseased plants are often smothered by those that are healthy. Several wild species of Ipomoea (morning glory) are hosts. Treatment: Treatment: Treatment: 78 49 112 106 Pholo: Grahame Jackson Pholo: Grahame Jackson Photo: Eric McKenz;e Photo: Brian This/le/ail ElsÎnoe hl/taras PholO: Grahame Jackson Psellûocen nspora {ÎII/orens;s ｐｨｙｬＨＩｰ｡ｾｭ (Lilll -Ieal disease) 79 ISCHAEMUM INDICUM UCTUCA SATIVA lACTUCA SATlVA BATIKl BLUE GRASS LETTUCE LETTUCE POACEAE ASTERACEAE ASTERACEAE CllrvlI/aria ;scllaemi Brem;a la.('llicae Cercospora IOllgissima Eye spot Downy mildew Leafspot Site of infection: L Site of infection: L Site of infection: L Importance of the disease: ｾ Importance of the disease: ｾ Importance of the disease: ｾ Symptoms Symptoms Symptoms Small spots, 0.5-1 mm diam., grey with a red to purple border. Light green to yellow, round to angular spots on the upper leaf surface, merging and later turning brown, soft and slimy. On the under surface, a white fungal growth containing the spore masses develops Linder humid conditions. This is an important disease capable of causing the rapid destruction of the plant. Round to irregular leaf spots, grey-brown with small, pale grey centres. Spores develop on both sides of the leaf. The spots often merge, killing large areas of the leaf, making it unfit for consumption. Treatment: 80 44 Treatment: 18 Treatment: 25 Photo: Kohler Collection Photo: Kohler Collection PholO: Kohler Col/eC/ion Photo: KoMer Collec/ion Photo: Eric McKenzie CrU"l'll/aria i.\l:I/(/('I/I; Bremia /m'/II 'ae ercospora /ollgissilllll 81 LACTUCA SATIVA IACroCA SATlVA LACTUCA SATNA LETTUCE LETTUCE LETTUCE ASTERACEAE ASTERACEAE ASTERACEAE , 'c1erotillia sclerotiomm Pseudumollus spp. PhysiulOboiC.'l1 disorder CoUar rot Bacterial rots Tipburn Site of infection: L,S,C Site of infection: L,S Site of infection: L Importance of the disease: '1/'1/ Importance of the disease: '1/ Importance of the disease: '1/'1/ Symptoms Symptoms Symptoms Damping-off, wilt, and a watery soft rot. Wilts begin to appear during mid-season or later. Watery soft rots occur at the base of the stem at ground level, spreading into the head and causing a general collapse of the leaves. Cottony mats of the fungus coyer the rots and give rise to irregular-shaped sclerotia which are white at first, then black, 2-10 mm diam. Many other vegetables are hosts, including beans, carrot, sweet pepper and tomato. Several bacterial species may be involved, causing leaf spotting, vascular browning and soft rots, especially during hot and wet weatber. Symptoms develop as the plants mature. A section through the stem may show rots in the vascular tissues where leaves are attached, and oozing foul-smelling rots at the collar. Browning and drying out at the margins of the inner heart leaves. Symptoms vary with variety, with some showing symptoms on ail the leaves. The exact cause is unknown, but thought to be associated with environmental conditions. It is more likely to occur when cool, wet weather is followed by dry, sunny periods. The disease may appear suddenly when the plants are near maturity and cause severe losses. Treatment: 82 127 Treatment: 114 Treatment: 136 PhOIO. Kohler Col/eclion PhOlo: Kohler Col/eclion Pholo: Kahler Col/eC/ion Pholo: Kohler Col/eClion 'f 'rolillicl .IC/eroliul"lIlII P.\CU,{OIllOl/CI, 'pp, Ph) ｊ｡｣ｩｧｯｊｾ ùisor<.ler (Tirbum) 83 lACTUCA SATIVA LUPINUSALBUS & L ANGU I1FOUUS LUP/NUS ALBUS & L ANGU TlFOUUS LETTUCE LUPIN LUPIN ASTERACEAE FABACEAE FABACEAE LcUuce mo aie potyvirus Colletotric1lum !illdemlll!ziallllm ScLerotinia minor Lettuce mosaic Anthracnose Stem rot Site of infection: L Site of infection: L,Fr Site of infection: S,R Importance of the disease: ,j,j Importance of the disease: ,j,j Importance of the disease: ,j Symptoms Symptoms Symptoms Light and dark green patches on the leaves, puckering, necrotic spots, yellowing and sometimes browning of the veins. Plants are stunted, yellow, with the tops of leaves roUing downwards, and unmarketable. An important disease, with varieties differing in reaction to the Dark streaks on the lower leaf suIface, and circular dark brown sunken spots on pods, bordered by a ring of white fungal growth, and a brown watery margin. The centre of the spots becomes pink during wet weather as spore masses develop. Seedlings are also attacked from seedborne infections of the fungus. Cowpea, French bean (lower photograph), and soybean, as weil as other legumes, are hosts. Dark brown spots on the stems and a rot of the roots. A thick white fungal growth covers affected areas in which sclerotia are produced. These are white at first and then black, 0.5-1 mm diam. The sclerotia also occur inside the stems. VIruS. Treatment: 84 72 Treatment: 35 Treatment: 126 Pholo: DPI Colleclion PholO: Kahler Col/eerion PhOIO: Kahler Col/eclion 1 Photo: Kohler Col/eclion L llul'e mo,>aic p Hy irus Pholo: OP! Col/eoion Collétot ricllum 1Îndellll/tl1ial1l1JlI PholO. Koh/er Col/eclion SclerotÎnùl mÎllOr 85 LYCOPERSICON ESCULENTUM LYCOPERSICON ESCULENTUM LYCOPERSICON ESCULENTUM TOMATO TOMATO TOMATO SOLANACEAE SOLANACEAE SOLANACEAE ;1ltemaria salan; AI1Je/;a ｩ［ｾＮｪＯｭ Fu!l'in Jit !l'a =Sclerolùtlll rulfsii = EarJy bJight Basal rot Tomato leaf mould Site of infection: L,S,Fr Site of infection: C,R Site of infection: L Importance of the disease: 1/1/1/ Importance of the disease: 1/1/1/ '/iU/OSpOrilllll fll!l'Ll/Il Importance of the disease: 1/1/ Symptoms Symptoms Symptoms Small, pinpoint to 6 mm, circular to angular brown leaf spots with concentric ridges, gi ving a characteristic target spot appearance. The spots merge and leaves wither and fall prematurely. Similar spots occur on the stems, but they are darker and more elongated. On the fruits, the spots are dark brown or black, sunken, extending over part or ail of the fru it. The rots become covered in black spore masses of the fungus. Other plants are hosts, including potato and tomato. Roots and collar regions are decayed and plants will. A characteristic of the disease is the production of pale brown sclerotia, 1-2 mm diam., amongst white fungal growth at the base of the stem and on plant debris in the soil. A wide range of cultivated plants and weeds are hosts, including beans, carrot, cucurbits, sweet pepper, sweet potato and taro. Pale yellowish-green blotches on the upper leaf surface with pale areas below. Light grey spore masses fOIm on the lower surface, becoming greenish-purpJe or brown later. Infected areas often merge and the leaf turns brown and withers, but usually remains attached to the plant. The disease appears first on the Jower leaves and spreads upwards during cool wet periods. Treatment: 86 7 Treatment: 11 Treatment: 54 Pholo: Koh/er Colleclion Photo: Eric McKenzie Pholo: Kahler Coi/eCiion PholO: DPI ColleCiion Pholo: Kahler Col/eelion Alœrnariu so/ani PholO: Eric McKel1zie Allul/a rolfsii Fil/via ji/lm 87 LYCOPERSICON ESCULENTUM LYCOPERSICON ESCULENTUM LYCOPERSICON ESCULENTUM TOMATO TOMATO TOMATO SOLANACEAE SOLANACEAE SOLANACEAE Leveillula fauricll =Oidiopsis fallrifa TlllinalepJWnls cllcllmeris =Rhizoctol1ia so/alli Pseudol1wllas o/allacearum Powdery mildew Fruit rot, Stem canker Bacterial wilt Site of infection: L Site of infection: S,C,R Site of infection: L,S,R Importance of the disease: -V-V Importance of the disease: -V-V Importance of the disease: -V-V-V Symptoms Symptoms Symptoms Spots mainly on the underside of the leaf, at first yellow, later light brown. Symptoms are similar to those caused by leaf mould. Unlike other powdery mildew fungi, Leveillula does not grow on the suIface of the leaf and it is difficult to see the spore masses of the fungus. Chili, eggplant and sweet pepper are also hosts. Brown, circular, slightly sunken spots up to 25 mm diam. on the fruits, with concentric light and dark brown rings. As the fruits ripen, cracks appear in the rots and a brown fungal growth develops. Fruits near soillevel are more susceptible to attack. Root and collar rot also occur and cause plants to will. In wet weather, white fungal growth co vers the base of the stem. If the disease develops slowly, lower leaves droop, leaflets curl downwards and adventitious roots develop along the stem; later the plants will. More commonly, plants turn slightly yellow and wilt suddenly. Internally, the vascular tissues and surrounding areas are brown. If a piece of the stem is placed in water, a white bacterial ooze streams from the cut surface. This is a diagnostic test for the disease. Many plants are hosts, including eggplant, peanut, potato and sweet pepper. Treatment: 88 73 Treatment: 135 Treatment: 115 Pholo: Kahler Collee/ion Ph%: Kahler Col/a"/ion Photo: Kahler Col/eclion Photo: Kahler Col/eClion PhOIO" DPI ColleClion Leve/llu{(/ wl/rira ThwzafephoTUS cllcLlmeri. Pselldl)1/I0naS o/u/7((Ceartllll 89 LYCOPERSICON ESCULENTUM LYCOPERSICON ESCULENTUM LYCOPERSICON ESCULENTUM TOMATO TOMATO TOMATO SOLANACEAE SOLANACEAE SOLANACEAE Physiologkal disorder rhysinlogical disorder Bacterial spot Blossom-end rot Sun scald Site of infection: L,S,Fr Site of infection: Fr Site of infection: Fr Importance of the disease: -Y-Y-Y Importance of the disease: -Y-Y Importance of the disease: -Y Symptoms Symptoms Syrnptoms Small, dark brown to black, irregular-shaped greasy spots on the leaves. Where infection is severe, leaves turn yeIJow and faIJ. On the fruit, small, raised, circular black spots with a watersoaked margin. The spots enlarge as the fruit increases in size becoming slightly sunken. Only the outer skin is affected. Water-soaked spots at the flower end of the green fruit, enlarging, darkening and colJapsing to form large black sunken areas. Secondary organisms invade the tissues. The disorder is caused by sudden reductions or irregular fluctuations in soil moisture levels. It is more common in light sandy soils. There is little agreement on nutritional factors which might contribute to the disorder. On green fruit, when foliage is sparse due to defoliation by, for example, early blight. Fruits bec orne yeIJow and ripen unevenly, or the injured areas become white and blistered, Jose water, and develop fIat, grey sun ken paper-like spots. These areas may be invaded by secondary organisms and develop rots. X(lI1tItOltlOlIG.lI Campe,\'tris Treatment: 90 154 pV. ｡ｩｲＩＨｴＺＮ￹ｳ･Ｇｾ Treatment: 17 Treatment: 134 Photo: Kohle,. Collec/ion PhOlo: Grahame Jackson Photo: Kohler Collec/ion Photo: Kohler Collection Photo: DPI Collec/ion XalilhlJ/l/OI/LI \ CUllIll/'l/ri,\ P\!. l'eSÎe'OlOrÎa Physiologil:al w'\OI'der (Blossoll1-enJ rol) Ph ,iolDgical dis mlcr (Sun s(;aIJ) 91 LYCOPERSICON ESCULENTUM TOMATO MALUS x DOMESTICA APPLE MANG/FERA INDICA MANGO SOLANACEAE ROSACEAE ANACARDlACEAE Phytoplarma =Mycoplasma-Hke or anism Physiological disordcr Glomerella cil1gllfata ==conetotricJllIm gloeosporioides Big bud Internai browning Anthracnose Site of infection: L,S,FI,Fr Site of infection: Fr Site of infection: L,FI,Fr,S Importance of the disease: ,j-j Importance of the disease: -J Importance of the disease: -J-J-J Symptoms Symptoms Symptoms Stems become erect, short, thick and purple; tlower buds become swollen, with green petals-hence the name of the disease-and normally domlant axillary buds develop shoots. Leatlets are small, curled upwards and yellowish-green or purple. Green fruits are hard, tough and woody. Similar symptoms occur on potato, and many legumes are also hosts. From the outside, fruits appear healthy, but when cut show a browning of the flesh which deepens on exposure to the light. The disorder may be due to low storage temperatures during transport (Iow temperature breakdown), or to excess carbon dioxide in the storage atmosphere (brown heart). Small black irregular-shaped spots on the leaves, sometimes restricted by the veins, but often expanding to form large areas that dry and faU out. New leaf flushes are especially susceptible to attack. ln wet weather, infection of the tlowers may lead to a blossom blight, resulting in low fruit set. On fruits, pinpoint infections expand as the fruits ripen, forming dark brown to black spots with pink spore masses developing at the centre. Many other plants are hosts, including avocado, coffee, eggplant, papaya, sweet pepper, tomato and yams. Treatment: 92 107 Treatment: 70 Treatment: 62 Photo: Eric McKenzie Pholo: OP! Colleclion Pholo: Kohler Collection Photo: Eric McKenzie Photo: Kohler Col/eclion Phylllpla.ma (Big hud) Physlologil'aJ t1isonJer Internai browllll1g) 93 MANGlFERA INDICA MANG/FERA IND/CA MANGIFERA IND/CA MANGO MANGO MANGO ANACARDIACEAE ANACARDIACEAE ANACARDIACEAE Stigmùllll1umgijerae =Cercmpora nlatlf,JÏferae Oidillm sp. XallthomOllas campeslri5 pv. I/umg({eraeilldicae Angular leaf spot Powdery mildew Black spot Site of infection: L Site of infection: L,FI,Fr Site of infection: L,S,Fr Importance of the disease: 1/1/ Importance of the disease: 1/ Importance of the disease: 1/1/ Symptoms Symptoms Symptoms Spots at first scattered, black, circular to angular, up to 6 mm diam., surrounded by a wide greenish zone. Later, spots may merge forming large black areas. During wet weather the disease causes yellowing of the foliage and early leaf fall. White, powdery fungal growth over the shoots, fJowers and young fruit. Fruits faU prematurely. On older fruits, brownish scabby areas may develop due to earlier infections. (Oidium sp. is the asexual stage of Erysiphe spp. and other powdery mildews). Black, angular, raised spots between the veins on the leaves, often with yellow haloes. The spots merge, destroying large areas of the Jeaf. Spots also occur on the Ieaf stalks and, on the stems, may lead to gum-filled cankers. On the fruits, black oval to irregular-shaped raised spots develop. These may join together, and cracks may form from which sap emerges. Symptoms are similar to anthracnose and also to those of Stigmina, except the spots are more angular and they appear raised at the margins. Treatment: 94 132 Treatment: 87 Treatment: 152 Photo: Eric ,\tfcKenzie PhoTO: Kahler ColleclioTl Photo: Kahler CollectioTl PhoTO: Kahler CollectioTl Pholo: Kahler CollectioTl Photo: Kahler CollectioTl Sfixmilla lIIo/lgijèrae Oidi/lm "p. XUJ/f!lO/l/O/lUS CCI/1lpestris pV. lIlaIl8{t'eraeindicae 95 MANlHOT ESCULENTA MAN/Hor ESCULENTA ｾａｦｈｏｬＧ CASSAVA CASSAVA CASSAVA EUPHORBJACEAE EUPHORBJACEAE EUPHORBJACEAE (i!onwrella CÙ1KuilLfa Myco.'lphaerella /zellllÏllgsii =Cercu poridilll1l ｩｽＡｾｬ￙･ｴｬ Perù.'ol1ia malli/lOticala =Collelofriclllll1l ﾷＮ･ｬｴｩＩＨｲＱｰＧＮＩＨｬｏｉｾ Anthracnose Brown leaf spot Anthracnose Site of infection: L,S Site of infection: L Site of infection: L Importance of the disease: ,j Importance of the disease: ,j Importance of the disease: ,j Symptoms Symptoms Symptoms Leaf spots on young leaves, petioles and stems, causing partial or total defoliation and loss of tuber yield. Black shiny dots of the fruit bodies of the fungus commonly occur on the leaf spots. The disease appears to be much more serious in African than Pacifie countries. Many other plants are hosts, including avocado, coffee, eggplant, mango, papaya, sweet pepper, tomato and yams. Circular leaf spots, up to 15 mm diam., becoming angular and limited by veins, brown on upper surfaces with dark borders, sometimes surrounded by indistinct haloes. On the underside, the spots are grey with less distinct borders. The centres of the spots dry, crack and may fall out. The disease usually occurs on the older, lower leaves. Leaf spots, round, up to 10 mm diam., with small pale centres, brown borders, and wide greyish-purple haloes, often merging. Treatment: 96 62 Treatment: 84 ESCULENTA Treatment: 93 PhOIO: Kohler Col/eclion Photo: Kohler Col/eclion Photo: Eric McKenzie Photo: Kohler Colleclion Photo: Kohler Colieclion Myco,\plllœrt'llll hl!nnin.':.I'ii PenconÎa IIIwlil1ol/("O!a 97 MANlHOT ESCULENTA CASSAVA MANlHOT ESCULENTA CASSAVA LUCERNE EUPHORBIACEAE EUPHORBlACEAE FABACEAE XlUlthomOlUlS campestris pv. mani/lOtis Cassava green moUle nepovirus Uromyces striatus Cassava bacterial blight Cassava green moUle Rust Site of infection: L,S,Fr Site of infection: L Site of infection: L Importance of the disease: .J.J.J Importance of the disease: .J.J MEDICAGO SATIVA Importance of the disease: .J.J Symptoms Symptoms Symptoms Initially, angular water-soaked spots, more clearly seen on the lower leaf surface, sometimes with yellow haloes above, rapidly expanding and turning brown. Leaves wilt, dry out and fall. Leaf stalks are also attacked, leading to infection of stems and branch dieback. Pale yellow drop lets form on the spots and ooze from cracks in the stems. Spots also occur on the fruits and seeds. Faint or distinct yellow and green patterns, often on puckered leaves with distorted margins. Symptoms are most noticeable on the youngest leaves. Usually, plants recover to give slightly 1 stunted, but otherwise apparently healthy shoots. Occasionally, plants remain severely stunted, without producing edible roots or, if formed, they are small, and woody when cooked. Reported only from the island of Choiseul in Solomon Islands. Round or irregular-shaped pustules, mostly on the underside of the leaf. Infected leaves turn yellow and fall. Treatment: 98 153 Treatment: 21 Treatment: 142 Photo: Graham" Jackson PhOfO: Grahame Jackson Photo: Kahler Col/eCf/on Photo: Grahome Jackson Photo: Graham" Jackson Photo: Kahler Col/"C/ion Xalltho/ll(lllQS c(/Jllpestris pV. 1I1111Li/lOIis Cassava green mOllIt: nepovirus UromyCi!S stria/lls 99 MOMORDJCA CHARANTlA MONSTERA DELIC/OSA MU AS. BITTER MELON CUCURBITACEAE SPLIT LEAF PHILODENDRON ARACEAE BANANA MUS ACEAE CollelotricJllIlII 'p. PUt cillia paul/ilIa Cordallll nlll.me Anthracnose Rust Cordana leaf spot Site of infection: L,Fr Site of infection: L Site of infection: L Importance of the disease: ..j Importance of the disease: ..j Importance of the disease: ..j Symptoms Symptoms Symptoms Large, irregular-shaped necrotic blotches on the Ieaves, flower stalks and fruits, leading to withering and death of the affected parts. Leaf spots, round, yellow to orange, either isolated or joining together. The spots are smooth on the upper surface of the leaf, and powdery beJow, due to the production of spores. Large leaf spots, up to 100 mm, pale brown or yellow, oval or diamond-shaped, usually surrounded by a yellow halo. The spots occur on and between the veins. Often the entire edge of the Jeaf may be infected with an uneven, zigzag, yellow band separating diseased from green tissues. Infections often occur on leaf spots caused by the black-cross fungus, Phyllachora musicola, or leaf bJotches associated with Deightoniella torulosa. Treatrnent: 100 36 Treatrnent: 118 Treatment: 40 Photo: Kohler Col/ection Colle(o/I"ic!II/l11 . p. Pholo: Kohler Col/ection Pholo: Kohler Col/ec/ion Puccinia pal/lill/li 101 MUSA P. MUSA P. MUSA P. BANANA BANANA BANANA MUSACEAE MUSACEAE MUSACEAE Guigllardia musae =PhylkJs/icta 1Tl1lsarul1l Mllrasmiellus inode17lla Fusarium wilt, Panama disease Freckle Stem rot Site of infection: S,R Site of infection: L,Fr Site of infection; L,S,R Fli arium oxysporlll1l r. sp. cuhense Importance of the disease: -J-J-J Importance of the disease: -J Importance of the disease: -J-J Symptoms Symptoms Symptoms Leaf margins turn yellow, then brown, and the leaf tissue dies towards the midrib; older leaves wilt and hang down around the pseudostem. Occasionally, on sorne varieties, the stems split. Internally, the water-conducting strands of the stem, leaf and bunch stalks turn yellow, red, brown or black. If bunches develop they rarely fil! properly. Suckers may also show similar symptoms. The roots decay and the plants collapse and die. Raised black pinpoint spots occurring in groups on the upper surface of the Ieaves and also on the fruit. The spots contain the fruiting bodies of the fungus. Outer [eaf sheaths and leaf blades wither and decay, leaves are slow to emerge and are stunted. White or pink fungal growth commonly occurs between the leaf sheaths, and in wet weather mushrooms develop on the pseudostem and on debris on the soil. The roots may a1so be attacked. Coconut (embryo and basal shoot rot), maize and ri ce (root rots), and taro (shallow corm rot) arc also hosts. Treatment: 102 58 Treatment: 67 Treatment: 78 Fu.wril/ft/ O.\)'SIWI"WII r. PholO: DPI Colleerion Photo: DPI Colleet;on Pholo: Kahler Collection Photo: DPI Collection Photo: DPI Collection Photo: Eric McKenzie p. cLlhel1.1'e Gui/?!Iardia II/lISlle Marct.l'I/lielllls inodenna 103 MUSA SP. MUSA BANANA BANANA BANANA MUSACEAE MUSACEAE MUSACEAE Mycosphaerellll fijie1lsi'i =Paracercospora fijie1lsi ' MYf().'ipluœrel/fl mwiicola =1'seudfJcercfJspora l1111sue Pilyllac/wra l11usicola Black Sigatoka, Black leaf streak Sigatoka, YeUow Sigatoka Black-cross Site of infection: L Site of infection: L Site of infection: L Importance of the disease: --J--J--J Importance of the disease: --J--J--J Importance of the disease: --J Symptoms Symptoms Symptoms Red-brown streaks, initially }-5 mm long and 0.25 mm wide, on the underside of the third or fourth Ieaf, gradually forming elongated spots with grey or light brown centres and dark brown or black margins. Yellow zones occur between diseased and healthy tissues. ln severe attacks, spots do not occur, but large areas of the 1eaf turn black, dry out and wither. A characteristic of the disease is the occurrence of streaks in bands several cm wide on either side of the midrib; sometimes the streaks are more numerous at the tips and edges of the Ieaves. Yellowish streaks, at first on the third or fourth 1eaf, 3-4 mm long and 1 mm wide, en1arging into elliptical grey spots with a dark brown border, up to 15 mm long and 5 mm wide. In wet weather, the spots merge to form large, greybrown, dry, dead areas and the leaves collapse prematurely and hang down around the pseudostem. At harvest, few leaves remain and the bunches are small and ripen early. In most islands of the Pacific, M. musicola appears to have been replaced by M. fijiensis. Black four-pointed stars, up to 60 mm long, most prominent on the lower surface of older Ieaves, with the long axis of the star paralle1 to the leaf veins. The spots are scattered or sometimes occur in large groups. Spores develop on the dark lines. Sometimes, Cordana musae leaf spots are centred on the black-cross lesions. Treatment: 104 83 P. Treatment: MUSA 85 P. Treatment: 102 Pholo: Grahome Jackson '1 PholO: Brian ThiSllelon 1 • PlwlO: Kahler Col/eclion Pholo: Eric McKenzie Mycosplwerdla jU/en 'lis Photo: Brian Thisllelon Mye(J.I [J Iw (' re l/lJ !JIll \'ic' (1/ a Phyll(/('lIo/"{/ nW\'it.:(J/Ci 105 MUSA SP. MUSA 8P. MUSA SP. BANANA BANANA BANANA MUSACEAE MUSACEAE MUSACEAE Uredo 11111sae Vertici/lium theobromae Em'iI,ia spp. Rust Cigar end rot Wilt Site of infection: L Site of infection: Fr Site of infection: L,S Importance of the disease: ｾ Importance of the disease: ｾ Importance of the disease: ｾ Symptoms Symptoms Symptoms Pustules on both sides of the leaf surface, but more numerous on the lower surface, often associated with small dark streaks up to 3 mm long. The streaks sometimes merge to form speckled blotches. Early symptoms are similar to those of yellow Sigatoka. Firm rot, spreading slowly, up to 20 mm, along the fruit, beginning from a flower infection. Affected are as blacken and shrink; later, they become covered with the spores of the fungus and resemble the ash of a cigar-hence the name of the disease. The tissues inside the fruit develop a dry rot, with a sharp margin between diseased and healthy tissues. Wilting and death of leaves before the fruit has ripened. The centre of the pseudostem rots, with some discolouration of the vascular tissues of the outer leaf sheaths, sometimes extending into the stalk of the fruit. The disease has been identified on a local variety in the Federated States of Micronesia, although a similar condition is reported from Marshall Islands. E. chrysanthemi and E. carotovora have been isolated from affected plants. Treatment: 106 139 Treatment: 149 Treatment: 53 Photo: Eric McKenzie Photo: Cral1ame Jackson PhOIO: Kohler Col/eCiion Photo: Eric McKenzie Uredo mUSai' Ver/ieil/ill/II /lll'o/)mllwe Envinw Spp. 107 MUSA P. BANANA MUSA P. BANANA MUSACEAE MUSACEAE MUSACEAE Radopho/u. imilis Barums bunchy top nanavirm; Banana ·trcak badnaviru. Radopholus root rot Banana bunchy top Banana streak Site of infection: S,R Site of infection: L,S Site of infection: L MU Ji P. Importance of the disease: -J-J-J BANANA ImpOltance of the disease: -J-J-J Importance of the disease: -J-J Symptoms Symptoms Symptoms Reddish-brown or black rots, often several cm long, on the root, sometimes with cracks. The areas of rot are at first outside the vascu lar tissues; later, they spread throughout the root, causing total decay. As the nematode burrows into the corm, black spots with red margins develop. These rots, known as 'blackheads', may extend up to 20 mm into the corms. Plants are weakened by the root attack and are readily blown over during storms. Many crops are hosts, including bele, giant swamp taro, ginger, legumes, maize and yams. Initially, dark green dots and streaks, up to 25 mm in length, on the veins of leaves otherwise of normal appearance. The dark lines continue into the midrib as 'hooks'. Yellowing of the veins may also occur. Subsequent leaves show the same symptoms and are progressively smaller, erect and briule, with pale ragged necrotic margins. The stunted leaves become bunchedhence the name of the disease. Symptoms can appear on plants of ail ages. If they occur at an early stage of development, plants fail to produce fruit. Broken or continuous chlorotic streaks and narrow lesions, either scattered or in bands on the leaves. The streaks and lesions become necrotic, producing black-streak patterns as the leaves age. Initially, they appear similar to those caused by cucumber mosaic cucumovirus. Infected plants may be smaller than normal and less vigorous, with small bunches. In some African countries, dieback and internai necrosis of the pseudostem occur. Treatment: 108 123 Treatment: 13 Treatment: 14 Phora: John Bridge Phoro: Graham" Jackson Pilora: John Thomas Phora: DPI Collection Phora: DPI Colleerion Phora: John Thomas Rad(l[l!w{,/ \ \'Îmili.\ B<llla.na hum.;hy l )p nanavi ru.'" Banana slrea" b,u..lnu lru!> \09 P. PASPALUM DlLATATUM BANANA ORYZA SATlVA RICE MUSACEAE POACEAE POACEAE CUl'umb 111ugnaportlle all'i,,;; =1 aklltllea sigmuidell Ccrebella alldropogolli\ MUSA mo:aic clicumo\'irus l' PASPALUM, DALLIS GRASS Banana mosaic Stem rot Site of infection: L Site of infection: L,S Site of infection: Fr Importance of the disease: ..j Importance of the disease: ..j..j Importance of the diseases: ..j Symptoms Symptoms Symptoms Small, black irregular spots on the outer leaf sheath near the waterline. As the spots enlarge, the leaf sheath is partially or completely decayed and small black sclerotia form in the rotted tissues. Subsequently, the fungus invades the stem and the plant collapses. Dark fungal growths and sclerotia occur inside the stem. Brown-black spore masses with deep folds, developing on grass spikelets infected with ergot fungi (Claviceps spp.), and preventing the formation of ergot sclerotia. Many grasses are hosts. 1 Yellow streaks or flecks, sometimes with mild distortions. Usually, symptoms occur on a few leaves only, after which apparently healthy leaves are produced. Many crop plants and weeds are hosts, including cucurbits, legumes and members of the Solanaceae, for example, tomato and potato. Treatment: 110 43 Treatment: 74 Treatment: 28 Photo: DPI Collection saie ellclImovÎms Photo: Kohler Collection Ml/gllaporthe Wll'II/il Photo: Kohler Collee/ioll Ceri'hella llllJmpogollis 111 PASSIFLORA EDUUS PASSIFLORA EDUUS PASSIFLORA EDVUS PASSIONFRIDT PASSIFLORACEAE PASSIONFRIDT PASSIFLORACEAE PASSIONFRUIT PASSIFLORACEAE Alternaria alternata A/temaria passifTorac G/nmerefla cillgll/ata =Colletntricllllfll Kloeosporioide. Brown spot Brown spot Anthracnose Site of infection: L,S,Fr Site of infection: L,S,Fr Site of infection: L,Fr Importance of the disease: .,j.,j Importance of the disease: .,j.,j Importance of the disease: .,j.,j Symptoms Symptoms Symptoms Smal! spots with yellow or light-orange haloes on the leaves, up to 6 mm wide. Spots on the fruit have light brown centres with greasy, watersoaked margins, usualJy Jess than 10 mm diam. Brown spots, up to 10 mm diam., on the leaves, often extending along the veins and drying out in the centre. On the stems, spots are up to 30 mm long, and when they occur at the leafaxils may kil! the vine, resulting in dieback. On the fruit, the spots are light brown, round, and sunken; they often merge, covering large areas, and produce red-brown spore masses. Brown spot of fruit and leaves in Hawaii, Niue, Vanuatu and Western Samoa is associated with A. alternata. In Hawaii, this species has displaced A. passif/orae, and may also have done so in the other countries. White spots, up to 5 mm diam., on the leaves and fruits, developing into larger wrinkled rots on the fruits after harvest and covering part or a1l of the surface. On purple passionfruit, the spots are raised. Black fruiting bodies occur within the spots and the pink spore masses of the fungus become obvious during wet weather. Many other plants are hosts, including avocado, coffee, eggplant, mango, papaya, sweet pepper, tomato and yams. Treatment: 112 5 Treatment: 5 Treatment: 62 Photo: Kohler Collection Pholo: DPI Colleclion Phoro: Kohler Colla'iioll Phoro: DPI Col/ecrion Phoro: Kohler Colleuion Pholo: DPI Colleclion AI/t'morio (//renw/o A/remaria pllssi}7orcle GIOIl1CI'I'lId t'iJrgllfuw lB PASSIFLORA EDULIS PAS IFLORA QUADRANGULARIS PELARGONIUM ZONALE PASSIONFRUIT PASSIFLORACEAE GRANADILLA PASSIFLORACEAE GERANIUM Pas .,jonfruit woodinc:s pot},irus Allemaria pas Passionfruit woodiness virus Brown spot Rust Site of infection: L Site of infection: L,S,Fr Site of infection: L Importance of the disease: ..J..J..J Importance of the disease: ..J Importance of the disease: ..J..J Symptoms Symptoms Symptoms Yellow spots, yellow and green mosaic patterns with puckering and crinkling over large areas of the leaf. Fruits are small, deformed, with a thick hard rind, and have a small cavity. Infected plants defoliate and die back. The purple passionfruit is particularly susceptible to the VI rus. Wild passionfru it (P. foetida) and Jegumes, inc1uding centro, pean ut, soybean and siratro are also hosts. Symptoms are similar to those on passionfruit. Light brown, deeply sunken spots develop on the fruits, covered with dark spore masses of the fungus. Internai rots develop, which make the fruits unsuitable for consumption. Concentric circles of rust-coloured pustules on the lower Jeaf sLllface, surrounded by Jight green haloes, with green spots on the corresponding upper surface. As the disease progresses, the leaves turn yellow, but the affected areas remain green. Plants may become defoliated during severe attacks. Treatment: 114 90 Treatment: GERANIACEAE ･ｭｯＱｦｾ Puccinia pelargcm;i-WI111lis 5 Treatment: 118 Pholo: Grahame Jackson Photo: Kahler CollectÎon Pholo: Kahler Coileclion PholO: Wolfgang Gerlach Passionfruil wooùiness pol \'iru: A/fenil/ria /JlIssij7orae Pllc'cÎllia pt!larK'mii-:;.mwlis 115 PER BA AMERlCANA PER EA AMERlCANA PERSEA AMERlCANA AVOCADO AVOCADO AVOCADO LAURACEAE LAURACEAE LAURACEAE Gfo/llerella t:ÏlIgufala =Co/letotrichu/Il gloeo},porioides Lasiodiplodia theohrnmae =Diplodia lIatalèllsis Algalleaf spot, Red rust Anthracnose Stem end rot Site of infection: L Site of infection: L,Fr Site of infection: Fr Importance of the disease: ...; Importance of the disease: ...;...; Importance of the disease: ...; Symptoms Symptoms Symptoms Circular spots, 2--4 mm diam., green or redorange, usually on the upper leaf surface. Generally, the infections are of little economic importance, although they can cause premature Jeaf faH and weaken the tree during severe attacks. This may occur in areas where rainfall is very high. Many other trees are hosts, including black pepper, breadfruit, citrus, cocoa, guava, mango, and soursop. Two other species, C. minimus and C. parasiticus, are also present in the Pacific. Small, light brown circular spots on ripe fruit, enlarging rapidly and forming dark brown sunken areas of rot which cause extensive internaI decay. In wet weather, these become covered in pink spore masses of the fungus. Similar symptoms develop from wounds made on immature fruit, leading to fruit drop. On leaves, large Jight brown spots develop which may spread over the entire leaf blade, causing early leaf fall. Many other plants are hosts, including coffee, eggplant, mango, papaya, sweet pepper, tomato and yams. Brown to black fruit rot developing in storage or during transport. The first sign of the disease is a browning at the stem end, after which the rot spreads rapidJy through the f1esh. After 8-10 days, the skjn becomes covered in the black fruiting bodies of the fungus, which sometimes release masses of whitish spores. Many plants are host to this corn mon wound fungus, including breadfruit, citrus, cocoa and mango. 'eplwlellros IJirescefls Treatment: 116 23 Treatment: 62 Treatment: 71 Photo: Kohler Col/ec/ion Photo: Kohler Collection Photo: Kohler Col/ec/ion Photo: Kohler Col/ection Photo: DPI Col/ection Photo: Kohler Col/ection Cf011I erelia ＯＨｬｦｾｴｊｩＧ Lcllindipludilllltl'olmIllW( 117 PHASEOLUS VULGARlS FRENCHBEAN PHASEOLUS VULGARlS FRENCHBEAN Pl-IASEOLUS VULGARlS FRENCHBEAN FABACEAE FABACEAE FABACEAE Glomerella cillglliala =Collelofriclllllll gloeosporioides PJraeoisariopsi Kr;, cola ==lsariop!}'is griseo/a (fppefldiculalus Anthracnose Angular }eaf spot Rust Site of infection: L Site of infection: L,Fr,S Site of infection: L Importance of the disease: -J Importance of the disease: -J Ur011lyc:es apPcfldicu/atlis var. Impültance of the disease: -J Symptoms Symptoms Symptoms Round, light brown irregular-shaped spots on the leaves, spreading rapidly over the leaf surface. The spots dry out, the centres fall out, and the leaves drop prematurely. Many other plants are hosts, including avocado, coffee, eggplant, mango, papaya, sweet pepper, tomato and yams. Angular spots on the trifoliate leaves, up to 3 mm wide, limited by the veins, grey to light brown. On the primary leaves, the spots are up to ] 5 mm diam., and often zoned. Fungal growth develops on the undersides of both types of spot. Dark sunken spots of varying size also occur on the pods and stems. Pustules, at first light green; later, as spore masses develop, dark brown, 1-2 mm diam., and surrounded by yellow haJoes. The pustules occur on both sides of the leaf. The leaves yellow prematurely, but the areas around the pustules remaln green. Treatment: 118 62 Treatment: 97 Treatment: 141 Photo: Kohler Col/ecrion PhofO: Kuhler Cullection Phutu: Kuhler Col/t:Cliun Photo: DPI Collection Glolllerellu C'ÏlIglllalil P/IlI\'{'O; wriopxi \ gri ,'e(J/a U/TIII/YC/!\ flppeflllil'llfa/[(\ var, llPPl'fUJiCIIlafm 119 PHASEOLUS VULGAR1S PlNUS CARIBAEA FRENCHBEAN FABACEAE CARIBBEAN PINE PINACEAE J'vleloidogyTle spp. Cassy/ha filiformis Cucumbcr mosaic eUculllm1rus Root-knot nematodes Parasitic plant Kava wilt, Dieback Site of infection: R Site of infection: L,S Site of infection: L,S,R Importance of the disease: ｾ Importance of the disease: ｾ Importance of the disease: ｾ Symptoms Symptoms Symptoms Galls are best seen when roots are washed. Above-ground symptoms are similar to those caused by lack of nutrients or water. Plants may be stunted, yellow and wilt. Symptoms may be particularly severe if infections occur soon after planting. More often they occur at maturity, when plants begin to wilt and die back. In this case, fruit set and fruit fonnation are also affected. Disease is often worse in sandy and freedraining soils. Infection by root-knot nematodes facilitates the entry of fungal and bacterial pathogens. Many other plants are hosts, including banana, carrot, cucurbits, ginger (lower photograph), lettuce, okra, pulse crops, tobacco and yam. Macroptilium atropurpureum is also a host. The tendrils, which have suckers, wind around and become attached to the host plants. Generally not important, although it may damage plants in the nursery and those newly planted in the field. Yellowing of veins and yellow and green patterns on crinkled and puckered leaves. The stems below the infected leaves show brown streaks and/or patches of rot in the vascular and surrounding tissues. Sometimes, internai discoloured areas also occur in stems at soil level and in the roots. Later, after 3-4 weeks, the symptoms in the stems are noticeable externally. Large, black, soft rots develop and these cause the stems to break, often at the nodes. New shoots may develop from the base of the plants and these, too, show symptoms of the disease. Cucumber mosaic virus exists as a number of strains and has a very wide host range, including cucurbits, legumes and solanaceous species. Treatment: 120 79 Treatment: PIPER METHYSTlCUM KAVA PIPERACEAE 22 Treatment: 43 Photo: John Bridge Photo: Kohler Collection Photo: Richard Davis Photo: DPI Col/ection Photo: Kohler Col/eclion Photo: Richard Davis Me/oïl/ogy//(' spp. C(/.\', ."fha fï/({onllis 121 PLUMERIA SPP. PLUMERlA SPP. PRUNUS PERS/CA FRANGIPANI FRANGIPANI PEACH APOCYNACEAE APOCYNACEAE ROSACEAE ('o[eospOri1l11l plullll!rioi' L Rost Sooty mould Wilt Site of infection: L Site of infection: L,S Site of infection: S,C,R Importance of the disease: ..,j,j..,j Importance of the disease: ..,j Importance of the disease: ,J-j Symptoms Symptoms Symptoms Pustules occur on the under surface of the leaves, releasing spore masses which co ver them in a fine yellow-red layer. The disease occurred for the first time in the Pacifie Islands in 1990 and rapidly defoliated susceptible varieties. Brown-black mould on leaves and stems. The fungus does not penetrate the plant; growth is superficial and can easily be scraped off. Fungi causing sooty moulds grow on the secretions of insects, mealybugs, scale insects and aphids, in particular. Many other plants are hosts, including citrus, guava and mango. Root rot and wilt of the foliage. Young plants are particularly susceptible to attack by this soil fungus. The disease is more serious in soils Jow in organic matter. Treatment: 122 33 Fu 'ariulll o.\)'sportlm 'ooty moulû fungi Treatment: 129 Treatment: 57 Photo: Koiller Col/eClion '01 eo,'florit1111 l'II/Ille rillt' Photo: Eric McKenzie '0( ly IllUU!Ù fungl Photo: Kohler Collection rI/.Wrtllll/ O.\J 'I/O/'UIII 123 PSIDIUM GUAjAVA GUAVA PSIDIUM GUAJAVA GUAVA MYRTACEAE MYRTACEAE Tnmzsche/ia disc%r G/omerella Cillgu/lilo ==Cu/lelofric/1ll11l g/oeospodoides ｐ･ｳｬ｡ｯｩＨＩｰｳＮｾ Rust Anthracnose, Dieback, Fruit rot Fruit rot Site of infection: L,Fr,S Site of infection: S,Fr Site of infection: L,Fr Importance of the disease: -V-V-V Importance of the disease: -V-V Impoltance of the disease: -V-V Symptoms Symptoms Symptoms Small, irregular-shaped spots, at first pale yellow, on both sides of the leaf, later brown with yellow haloes and covered on the under surface with brown, powdery spore masses. Infected leaves turn yellow and fall; normally this occurs from the base of a shoot towards the tip. On the fruits, light brown, circular, sunken spots up to 5 mm wide. Spots may merge and develop cracks. Sm ail pale to dark brown, slightly raised cankers may develop on the new shoots. The taxonomy of this fungus is uncertain; two forms are recognised: T pruni-spinosae on wild species of Prunus and T discoLor on cultivated varieties. Bands of blackening on the fruits, extending around the central parts, with the upper and lower parts remaining green at first. Later, white, orange or pink fungal growth becomes visible on the rot. Fruits of ail stages are susceptible. Infection of young stems results in dieback. Guavas are often severely attacked by fruit flies and it is possible that anthracnose is associated with damage caused by these insects. Many other plants are hosts, including avocado, eggplant, mango, papaya, sweet pepper, tomato and yams. On the fruits, maroon rots beginning at the stalk end, rapidly expanding, and surrounded by folds of wrinkled skin. Fruiting bodies of the fungus form on the rots and these are at first white and then brown. Fruits can be totally destroyed by the attack. The fungus is also associated with grey leaf lesions. PRUNUS PERS/CA PEACH ROSACEAE Treatment: 124 137 Treatment: 62 dissemina/a Treatment: 96 Pholo: Kohler Col/eclion Pholo: Eric McKenzie PholO: Kahler CollectÎon Photo: Kohler Colle clion Trall;;.schelia di,len/or Photo: Eric McKenzie G/omerella cillgllla!a Pl';)wIOli (lSÜ di.'"lcmirwttl 125 RAPHA US SATIVUS RADISH RAPHANUS SATlVUS RADISH SACCHARUM EDULE DURUKA BRASSrCACEAE BRASSrCACEAE POACEAE Albugo cmu/it/ll XlwtlwmOllll.· campe Iris White rust Bacterial root rot, Black rot Fiji disease Site of infection: L Site of infection: L,S,R Site of infection: L,S Importance of the disease: ,N Importance of the disease: p". campe 'tris .y ＧｵｧＬｭＺｾｮ Fiji disrase t'ijivinls Importance of the disease: .y.y Symptoms Symptoms Symptoms Pustules on leaves and petioles, at first round, smooth, white and shiny, 1-2 mm diam.; later, powdery on the under surface when the spores are released. The pustules may merge to form larger patches. Severe attack results in distorted leaves which witt and die. Chinese cabbage and radish, as weil as many cruciferous weeds, are also hosts. Internally, a blackening of the vascular tissues of the roots, spreading to surrounding tissues. Many other crucifers are hosts, often producing characteristic yellowish V-shaped areas at the Jeaf margin in which the veins are clearly visible. The blackened veins may extend into the petiole and stem. This bacterium is more commonly associated with black rot of cabbage (lower photograph), cauliflower, Chinese cabbage and oLher crucifers. Galls on the veins, on the underside of the leaf blade, on midribs, and on the outside of the leaf sheath, varying in length from less th an 1 mm to 50 mm, and 2-3 mm wide. The galls are green at first, later, greenish-white. Infected plants have a grasslike appearance: leaves are dark green, stiff and short, and plants also look as if they have been grazed by animais. Other Saccharum species, including sugarcane (Iower photograph), are hosts. Treatment: 126 3 Treatment: 150 Treatment: 133 Photo. Kohler Col/ection Photo: Robin Palmer Photo: DPI Collection Photo: Bureau of Sugar Experiment Stations Photo: Kohler Col/ection A/hl/go candida , (l/lt!lOI11I1I1t1S Ｈ［｡ｬＱｰ･Ｌｾｴｲｩｳ rv. I"UIII{lC'stri,l' 127 SACCHARVM OFFICINARUM SACCHARUM OFFICINARUM SACCHARUM OFFICINARUM SUGARCANE SUGARCANE SUGARCANE POACEAE POACEAE POACEAE Ceratoc)'stis paradoxa DeightonieLlfl pllpllanll E/silloe .llacchari =Sphaceloma sacchari Pineapple disease Veneer blotch White rash, White speck Site of infection: S Site of infection: L Site of infection: L Importance of the disease: ,j,j Importance of the disease: ,j Importance of the disease: ,j Symptoms Symptoms Symptoms A disease of planting setts. Reddening on stems, followed by black areas of rot with a characteristic pineapple smel!. Buds fail to grow, and those that do die back or remain stunted. Banana, coconut and pineapple are also hosts. Leaf spots, initially smal!, oval, light green to pale yellow with a thin red-brown margin. Later, they become surrounded by a succession of 2-12 spots, each with a light green interior, becoming light brown, and outlined by a 0.5-1 mm wide dark red border. White oval spots, usually on the upper 1eaf surface, midribs and leaf sheaths, up to 3 mm long and 1 mm wide, with red-brown margins. Sometimes, the spots merge to form long narrow streaks. =Chnlara paralluxa Treatment: 128 24 Treatment: 48 Treatment: 51 PhOIO: Bureau of Sugar Experiment Stations CertJ!Ocysti.I"!JlIradoxa Photo: Gra/wme Jackson Deiglttol/ie/la papl/al/({ Photo: Eric McKenzie CI.I i 1/ (Je ,\li l' clw ri 129 SACCHARUM OFFICINARUM SOLANUM TUBEROSUM SOLANUM TUBEROSUM SUGARCANE POTATO POTATO POACEAE SOLANACEAE SOLANACEAE Glo/llerella tlIelimlille" \iis A/tenlllria solanl TIumaœp/wrlls clIclImer;s =( ollelotric lIu1II jll!l'llt li 111 =Rh;zoclollia solall; Red rot Early blight, Target spot Black scurf Site of infection: L,S Site of infection: L,S Site of infection: L,S Importance of the disease: ...j...j Importance of the disease: ...j...j...j Importance of the disease:...j...j Symptoms Symptoms Symptoms Small red oval spots on the midrib of the upper leaf surface, developing pale yellow to white centres, sometimes merging to coyer the length of the leaf. Similar spots also occur on the leaf blades. Stems are affected by internaI red rots with white patches, usually seen only when they are cut open. As the rots develop, the canes are easily broken. Maize, sorghum and sorne grasses are also hosts. Oval or angular leaf spots, at fjrst 3-4 mm diam., later, up to 20 mm, dark brown to black with concentric zones and yellow haloes-hence one of the cornrnon names of the disease. When the spots are numerous the Jeaves fall prematurely. The disease usually starts on the lower leaves, moving upwards. Spots rnay develop on the stems and tubers. Early blight is an important disease on potato and tomato, causing severe defoliation and large yield losses. Brown, dry sun ken spots on the stems, sometimes developing into cankers and causing stunting. Young shoots rnay be attacked as they grow from the seed piece and killed before emergence. Roots and stolons may also be infected. Brown or black sclerotia form on the tubers and these are firmly attached to the skin, but rots do not develop from them. Many other plants are hosts, including cabbage, lettuce, legumes, tomato and yams. On seedlings, R. solani commonly causes pre- and post-emergence damping-off. Treatment: 130 63 Treatment: 7 Treatment: 135 Photo: Kohler Collee/ioll Photo: Kohler Collee/ion Photo: Kohler Col/ec/ion Photo: Kohler Col/ec/ioll Photo: Eric MeKenzie Glome! r('/Ia /I((,lIl1/anensis Alrenwrifl .\'(Jlun; ThwlUle!pllOrtis cliclIIneri.l' 131 OLANUM TUBEROSUM SOLANUM TUBEROSUM SOLANUM TUBEROSUM POTATO POTATO POTATO SOLANACEAF SOLANACEAE SOLANACEAE Enllillia .'pp. Potato Je4lfroliluteoYirus Phytoplasma =Mycoplasma-lik or 'alUsm B1ackleg, Storage rot Potato leafroU virus Purple top wilt Site of infection: L,S Site of infection: L,S Site of infection: L,S Importance of the disease: 1/1/ Importance of the disease: Symptoms Symptoms Symptoms In the field, bacteria within the infected planting sett move into the shoot base, up the stem and into the above-ground parts causing dark brown to black basal stem rots-the blackleg symptom. Plants may wilt in hot weather. Daughter tubers are invaded through the stem end and develop brown wet soft rots. Tubers damaged in storage develop cream to Iight brown wet soft rots with a strong fouI smel!. Three bacteria can cause rots of this kind: E. carotovora pv. carotovora, E. carotovora pv. atroseptica and E. chrysanthemi. The last two are more common in the tropics. On plants grown from infected tubers, leaves become rolled upwards at the margins, beginning on the lower leaves. Tubers, if they develop, may be affected by an internai net browning, but this depends on variety. Plants may be stunted. If plants are infected by aphids, the symptoms appear first on the younger Ieaves, which become red, rolled and erect. Tomato is also a host. Leaves roll upwards and Jeaflets become pale yellow, or purple on pigmented varieties. Plants become stiff and erect. Normally dormant buds in the axils of the leaves grow, giving the shoots a bushy appearance. Aerial tubers may form in the Jeafaxils. Eventually the plants wilt, and at this stage a brown discoloration occurs in the vascuJar tissues at the base of the stems. The discoJoration may extend along the stolons into the daughter tubers. The last stages of the disease can easily be mistaken for wilt associated with Fusarium spp. Importance of the disease: Treatment: 132 1/1/ 52 Treatment: 108 Treatment: 1/1/ 107 Photo: DPI Collec/ion Photo: Kahler Col/ec/ion Phu/o: DPI Coliec/ion Photo: Kahler Coliec/ion Photo: Kohler Coliec/ion Erll'illia spp. Potala ｫ｡ｦｲｯｬｵｴ･ｶｩｮｾｐｨｙｌｯｰｬ｡ｾｴｮ (purple top wilL) 133 TACCA LEONTOPETALOIDES THEOBROMA CACAO THEOBROMA CACAO ARROWROOT COCOA COCOA TACCACEAE STERCULIACEAE STERCULLACEAE CerCO.\lJOra taerae MamsmÎus crill;veqllÎ Om:obmddiu11l1lzeohromae Leafspot Horse-hair blight Vascular streak dieback Site of infection: L Site of infection: L,S Site of infection: L,Fr,T Importance of the disease: "" Importance of the disease: Nil Importance of the disease: """ Symptoms Symptoms Symptoms On mature leaves, round to irregular grey-brown spots surrounded by bright yellow haloes. The spots merge and cause a yellowing and drying of the foliage; consequently tuber development is poor. Saprophytic. Smooth black fungal threads (rhizomorphs) overrun leaves and stems of living trees. The tangle of threads which deveJop retains dead leaves. This gives the false impression of excessive leaf fal! due to infection by the fungus, but sorne of the suspended leaves may have matured and fallen due to natural processes. Scattered green spots against a yelJow background on one to two Ieaves up to 1 fi behind the shoot tip. After a few days the Jeaves faU and those above and below begin to show similar symptoms. Lenticels enlarge, giving the bark a rough appearance. AxilJary buds develop. Growth of the diseased shoot slows, symptoms spread to the lateral branches and the tree dies. White spore-producing bodies form from the leaf scars. When diseased stems are split open, a diagnostic brown streaking is present in the vascular tissues. Treatment: 134 25 Treatment: Treatment: 88 Photo: Kohler Collection Photo: Chris Priar Photo: Crahame Jackson Photo: Chris Prior Photo: Kohler Collection Cel'cospora /accae Ｑｾ {/ l'liS 111111.\ criIl iSt'lj/l i OI/COhliSidi1t1ll fheo!Jm/ll{l1' 135 THEDBRDMA CACAO THEOBRDMA CACAO mEOBROMA CACAO COCOA STERCULIACEAE COCOA STERCULIACEAE COCOA STERCULIACEAE PhallerQchaele sa/numic%r =Corlicill1n .m/monicolor Phellinus 1l0XÙlS Phytophthora palmivora Pink disease Brown root and collar rot Black pod, Canker, Leaf blight Site of infection: S,T Site of infection: T,R Site of infection: L,Fr,T Importance of the disease: -J-J Importance of the disease: -J-J Importance of the disease: -J-J-J Symptoms Symptoms Symptoms Branches and trunks are covered in a whitish pink crust which fades to cream with age. Often, the first symptom of the disease is the sudden death of an entire branch, with the brown leaves remaining attached. The bark may crack and gum may form. Spread of the fungus to the jorquette may result in death of the tree. Many other plants are hosts, including black pepper, citrus, coffee, rubber, tea and sorne forest trees. Roots becorne encrusted with soil which is held together by the thick brown growth of the fungus. On the trunk, the fungal growth, which may show a white margin, can reach 1.5 m from ground level. Cracks may occur in the bark through which gum may exude, and the wood becomes discoloured and dry. Trees suddenly wilt when the fungus destroys the roots or girdles the trunks. The disease often spreads along the line of trees. Fruit bodies may form several years after the death of the tree, on logs and stumps of forest trees or on those used for shade. Many other trees are hosts, including coffee, Leucaena sp. (lower photograph), mango, oil palm and forest trees. Angular brown spots on leaves and succulent stems, causing a blight of young shoots and seedlings in wet weather. Brown spots on the fruits expand rapidJy producing a white fungal growth containing spores behind the margin. Fruits blacken within a few days. Red or brown cankers develop as the fungus grows from the fruit into the branch and trunk. Girdling leads to branch death and dieback. Many other plants are hosts, including black pepper, breadfruit, coconut, papaya and vanilla. Treatment: 136 98 Treatment: 100 Treatment: 104 Photo: Chris Prior Photo: Kahler Col/eclion PholO: Chris Prior Photo: Chris Priar Photo: Grahame Jackson Photo: Chris Prior Photo: Wolfgang Gerlach Photo: Grahame Jackson P/IOf/el'O('//iJele .l'a/Illon ic%r Plle/lif/lls 1/0X;W Phytophthora pa/m;l'oro 137 VANDA P. TRITICUM AESTIVUM VANDA WHEAT VANDA VANDA POACEAE ORCHIDACEAE ORCHIDACEAE U\'ti!ago tritici G/o11lcrelfa ciIIgII/ata =CulletotricJWIIl gloeosporioide,'i Phytop"thora llicotimUlf! nu', parm'itica =1'11ytofJhthora pllrasilica Loose smut Anthracnose Heart rot Site of infection: FI,Fr Site of infection: L,S Site of infection: L,S Importance of the disease: ｾ Importance of the disease: ｾ Importance of the disease: ｾ Symptoms Symptoms Symptoms The flower head, except the stalk, is replaced by smut spore masses. The spores are black, dry and powdery, and they are often blown away by the wind, Jeaving only the bare stalk and the remains of the fJower parts. Large brown blotches on the leaves, often starting at the tips. Flower stalks are also affected. Fruiting bodies of the fungus usually develop in the decayed tissues. Many other plants are hosts, including avocado, coffee, eggpJant, mango, papaya, sweet pepper, tomato and yams. Leaves at the centre of the plant are easiJy pulled out and show large, wet, purple-brown or black rots at the base. Ali parts above the rot are killed. Treatment: 138 145 P. Treatment: 62 Treatment: 105 Photo: Kohler Col/ection PholO: Kohler Col/ec/ion PholO: Kohler Col/ec/ion PholO: Kohler Col/ec/ion Photo: Kohler Col/ec/ion Pholo: Kohle,. Col/ecrion Usri /af{o tri/ici Glumerelll1 cillgll/ata Ph_vtnplll!/()/,u nicotiwlCIe var. [JlIrasi/ica 139 VANDA SP. VANDA VAN/UA FRAGRANS VANILLA VANlLIA FRAGRANS VANILLA üRCHIDACEAE üRCHIDACEAE üRCHIDACEAE SclerotiTlia :p. Fusar;utll oxyspomm Glomerella cillgulata =Col/etofricllllm gloeosporioide' Dry rot Stem rot Anthracnose Site of infection: S,C,R Site of infection: S Site of infection: L,Fr,S Importance of the disease: ,j Importance of the disease: ,j,j Importance of the disease: ,j,j Symptoms Symptoms Symptoms A dry rot at the collar, leading to the destruction of the plant. White fungal tufts develop and these form into cream or white sclerotia, occurring either singly or in groups. Yellow spots on the stems, spreading rapidly, becoming slightly sunken and black. Symptoms are similar to those caused by Phytophthora palmivora and Colletotrichum gloeosporioides. Another Fusarium, F. oxysporum f. sp. vanillae, causes a root-tip rot on roots growing in leaf litter, mu\ch or soil. Infection does not lead to a wilt because the fungus does not spread through the vascular tissues. Instead, a slow dieback occurs, with new roots developing from the vines continually destroyed as they reach the soil. Rhizoctonia solani is associated with these rots. Brown, slightly sunken, rapidly expanding spots on Ieaves, pods and stems. Stem lesions may girdle and kilt the vines. In wet weather, the lesions are covered in pink spore masses. Symptoms are similar to those caused by Phytophthora palmivora and Fusarium oxysporum, and are difficult to diagnose if fruiting bodies are absent. Many other plants are hosts, including avocado, coffee, eggplant, mango, pa paya, swcet pepper, tomato and yams. Treatment: 140 125 Treatment: 56 Treatment: 62 Photo: Kahler ColleLl;on Pho!O: Kohler Collecrion Photo: Kohler CoUec/ion Photo: Kohler Colleetioll Sderoliflia 'p. FUSlIri1l1fl oxy.IJW""1/I CtoIT/crcflli ＯＨｉｬｌｾｮｩ｣ 141 VANlLIA FRAGRANS, V. TAHlTENSfS VAN/LIA FRAGRANS, V. TAHITENSfS VAN/LIA FRAGRANS VANILLA VANILLA VANILLA ORCHIDACEAE ORCHIDACEAE ORCHIDACEAE Phytophthora palmiwn-a anilla mo -aie pOl)"vinw Stem rot Vanilla mosaic virus Vanilla necrosis virus Site of infection: L,Fr,S Site of infection: L Site of infection: L Importance of the disease: ,j,j,j Importance of the disease: ,j,j Impoltance of the disease: ,j,j,j Symptoms Symptoms Symptoms Rapidly spreading spots, causing pod and leaf fall, stem decay, and blights during wet weather. Symptoms are similar to those of Fusarium oxysporum. In French Polynesia, P nicotianae var. parasitica and P capsici have also been found associated with vanilla blight. Many other plants are hosts, including black pepper, breadfruit, cocoa and coconut. Leaves with yellow and green mosaic patterns and distortions, especially along the margins. Distorted margins and leaf blades of young growth, with sunken yellow or white patches. On the older leaves, black, raised, scab-like spots occur and, later, black les ions develop on the stems. Vines defoliate and die. Treatment: 142 104 Treatment: 147 Treatment: 148 1 PholO: Mike Pearson PhOfO: Mike Pe{/rJon Photo: 8ill Zeu/er Pilolo: Mike Pearson Photo: Kahler Collec/ion },hYI(I['!II!1oro !wlmivo/"U VanJlI:l ll10saic POlYVll1lS VaJlilla nel.:rosi.., potyvirus 143 VIGNA UNGUICUIAIA SESQUIPEDALIS VIGNA UNGUlCULATA SESQUIPEDALIS YARD-LONG BEAN YARD-LONG BEAN YARD-LONG BEAN FABACEAE FABACEAE FABACEAE Oïdium 'p. Uromyces vignal! Blacke}f cowpea mosaic potyvirus Powdery mildew Rust Blackeye cowpea mosaic Site of infection: L Site of infection: L Site of infection: L Importance of the disease: ...J...j Importance of the disease: ...J...J Importance of the disease: ...j...j Symptoms Symptoms Symptoms Superficial sparse, white, powdery growth on one or bath leaf surfaces. The fungal growth is often associated with red blotches, usua]Jy on the lower leaf surface. Often leaves have dual infections of powdery mildew and rust, Uromyces vignae (lower photograph). Many other species are hasts, including avocado, cucurbits, and papaya. (Oidium sp. is the asexual stage of Erysiphe spp. and other powdery mildews.) Brown or black pustules on bath leaf surfaces, in small concentric rings. The pustules also occur on leaf stalks. Other Vigna spp. are hasts, including cowpea and sea bean (Vigna marina). Leaves show green and yellow patternsmosaics, mottles, and streaks. They also become distorted, with puckered surfaces. Plants are invariabJy stunted, and pod production is low. Many other Jegumes are hasts, including cowpea, French bean and soybean. Treatment: 144 87 Treatment: 143 VIGNA UNGUICUIATA Treatment: 16 ESQUIPEDAUS Photo: Grohamtt. Jackson Photo: George Wall Photo: Eric McKenzie Photo: Eric McKenzie Photo: Eric J\1cKenzie DilIi 1/171 P 145 ｾａｍ XANTHOSOMA SAG1TT1FOUUM TANNIA, FUI TARO, TARO PALAGI ZEA MAYS ZEA MAIZE, CORN MAIZE, CORN ARACEAE POACEAE POACEAE Cocl1li0/10/IiS !zeleroslrop!zll.\ =Bipo/aris mllydis Gibberella fujikoroi =FII.mriuIII monilijol11le Dasheen mosaic Southern leaf blight Kernel rot Site of infection: L Site of infection: L,Fr,S Site of infection: L,Fr,S Importance of the disease: '1/ Importance of the disease: '1/'1/'1/ Importance of the disease: '1/'1/ Symptoms Symptoms Symptoms Yellow, sometimes grey-green, streaks and blotches on the upper leaf surface, often giving a feather-like pattern along the veins. Occasionally, leaf blades are reduced in size. Usually, two or three leaves show symptoms and then apparently healthy leaves are produced. Corms do not show symptoms, and there is no evidence that the virus causes a loss in yield in any of the edible aroids. Ornamental species may be severely distorted by the virus. Taro, giant taro and giant swamp taro, as weIl as many ornamental species such as Caladium and Dieffenbachia, are hosts. Light brown leaf spots with a brown margin, at first elliptical, becoming rectangular, up to 25 mm long and 2-6 mm wide. The spots are at first restricted by the leaf veins, but later they may merge. Leaves dry out and die prematurely. Spots produced by Race Tare larger, spindleshaped or elliptical, with yellow or yellow-green haloes and dark red-brown borders, occurring on aIl above-ground parts. A black, felt-like mould may coyer the affected kernels. Sorghum and some grasses are also hosts. Grey or pinkish-white fungal growth over the grains, developing in storage on cobs that have not been dried properly. The fungus produces a toxin which affects horses and humans. ｾＩ sheen m )sail' l>otJvirus Treatment: 146 45 Treatment: 30 Treatment: 61 PIIOIO: Kahler Col/a'lion Pholo: Grahame Jack,wn PhUfO: Kohler Col/enion Photo: Eric ;WcKenzie PhOIO: Da Ｑｾ･ｨ mosaÏL Grn!1a/l/(, Jacholl putYVJrlIS PhOIO: Kahler ColleeliOIl Coe IIholwlus !le'f('rO.\'lmpIW\ Gi!Jhere!la /il/ikomi 147 ZEA MAYS MAIZE,CORN ZEA MAYS ZEA MAYS MAIZE, CORN POACEAE MAIZE, CORN POACEAE Puccinia sorghi . etosphaeria htrcica =Exserohilul1l turciClll11 Sugarcane downy rnildew Cornmon rnaize rust Northern leaf blight Site of infection: L Site of infection: L,Fr,S Site of infection: L POACEAE Pemno.'lclerospora sacehari =Sdero poru {Lecha"; Impol1ance of the disease: -J-J Impol1ance of the disease: -J-J Importance of the disease: -J-J Symptoms Symptoms Symptoms At first, smal!, round, yeIJow spots on the leaves leading to pale yellow to white stripes as the fungus becomes systemic. Several stripes may be present on each leaf, often extending the entire length. A white downy fungal growth develops on both leaf surfaces and husks. Plants may be stunted, with poorly developed ears. Sorghum and sugarcane are also hosts. Circular pustules, powdery, brown, becoming brown-black as the plant matures. The pustules occur on all above-ground parts, but are most common on the leaves, where they are scattered on both surfaces. In severe cases, the leaves and leaf sheaths turn yellow and die prematurely. Stages of P. sorghi occur on OxaLis spp. (lower photograph). P. sorghi is one of two common rusts of maize; the other is P. poLysora. Pustules of P. sorghi are sparse and common on both surfaces of the leaf, whereas those of P poLysora occur in groups, mostly on the upper surface. Often, the two rusts occur together requiring microscopie examination to distinguish them. Large, usually elliptical, grey or light brown leaf spots, sometimes with dark margins, 25-150 mm, at first on lower leaves. Brown fungal growth containing the spores occurs on the spots, often in concentric zones. The disease causes leaves to dry out and wither. Treatment: 148 94 Treatrnent: 119 Treatment: 128 Permit/ Icfe/"O 1/)(l1ï/ Photo: Mike Pearson PhOlo: Kahler Collec/ion Photo: Kahler Col/ec/ion Photo: Mike Peor.lun Pho/u: Kahler Col/ecliol1 Photo: Kuh/er Col/ec/ion \(/('('110 ri Pltccinia l'()rglli Selo"J)/weria IlIrL'Îl.'ll 149 ZEA MAYS ZEA MAYS ZlNGIBER OFFICINALE MAIZE,CORN MAIZE, CORN GINGER POACEAE POACEAE ZINGIBERACEAE Vstifago zeae Maizc mo. 'aie rhahdovirœ RadopllOlllS simili.\ Boil smut Maize mosaic Rhizome rot Site of infection: L,Fr,S Site of infection: L,Fr,S Site of infection: S,R Importance of the disease: ｾ Importance of the disease: ｾ Impoltance of the disease: ｾ Symptoms Symptoms Symptoms Blister-Iike gaIJs, up to 15 mm diam., splitting open to release black spore masses. AU the above-ground parts are susceptible to infection, especially when plants are young. Galts on the leaves remain smalt, 6-12 mm diam., become dry, hard and do not rupture. Early infection results in stunted plants and even death, but this IS uncommon. YeUow spots, short lines, broken to nearly continuous, fine to broad yellow stripes, often centred on the fine veins. Commonly, leaves also show long, broad yellow stripes and these may become necrotic. Stripes also occur on the sheaths, ear husks and stalks. Depending upon the time of infection and variety, plants may remain stunted, with the top of the plant bending to one side. Young plants are most susceptible. A characteristic of the disease is a shortening of the husks which exposes the ears. Grasses, Rottboellia (itchgrass) and Setaria, and sorghum are also hosts. Small, sunken les ions on the surface of the rhizomes, extending up to 10 mm into the host tissue. The channels become invaded by fungi and other secondary organisms and develop into extensive rots. Above-ground, the foliage is yeUow, the topmost Jeaves withered, and plants are stunted and lack vigour. The number of tiUers is reduced. Rots continue to develop in storage, causing significant losses. Many crops are hosts, including bele, giant swamp taro, legumes, maize and yams. =V.,·tilagQ l1I«ydis Treatment: 150 146 Treatment: 75 Treatment: 123 ｕｈｩＯＨｾＩ PhalO: Graham" Jackson Photo: Crahame Jackson Photo: Rohin Palmer Photo: l\1ike Pearson Photo: DPI Collection Photo: Rohin Palmer -:'('Ot! Maize mll...ai rhaoùovlru", Rat/op/lOfa IÎIIIÎfis [51 152 Control measures The purpose of this chapter is to help those who have identified a disease to take the necessary steps to bring about its control. Management of a plant disease is often complex, requiring the use of several methods to obtain the degree of control required. But for strategies to be useful they must do more than just control the problem; they must be economical, and of minimal risk to grower, consumer and the environment. The approaches that are commonly used are briefly mentioned below. Phytosanitary regulations: Sorne measures are not control techniques as such, but rather precautions to keep serious diseases out of a country or specified area. The measures come in the form of laws and regulations enacted by governments or locallegislatures. They are important safeguards against the introduction of pests not yet present, and in sorne cases the further spread of those that already occur. Of course, legislation cannot guarantee that the entry or spread of unwanted pests will be prevented, but it can be an effective barrier. It is made even more effective if combined with awareness campaigns to encourage the public to take an active part in the process. This is important, as many of the pests of Pacific Island countries have entered with unofficial plant introductions. Further, the use of local regulations, by-Iaws and the like, to stop the spread of diseases already present, can be used to advantage in Pacific countries. This is because they consist of islands and naturallong-distance movement of pathogens is often prevented by the intervening sea. Cultural control: The methods under this heading try to reduce the level of the pathogen so that infection is less likely to occur. There are several ways of doing this. Many of the methods are traditional practices that have stood the test of time, for instance, crop rotation, the use of organic manures or other soil amendments, and sanitation. Crop rotation aims to reduce the pathogen by growing non-host plants until it is judged safe to repeat the cropping cycle. Bush-fallows are used to obtain the same effect. Organic manures added to the soil may increase microbes antagonistic to soilborne plant pathogens. Lime and mineraI ash are also reported to be beneficial additions to the soil for the control of certain diseases, particularly those that are sensitive to pH. Sanitation includes a number of different techniques: elimination of plant residues from previous crops, either by removal, burning or deep burial; removal of weeds, alternative hosts or volunteer plants that may be reservoirs of infection; roguing or pruning of diseased plant parts; and disinfection of tools and machinery that might spread diseases. A method of a different kind is 'disease avoidance' . In this case, plants are grown ahead of their normal production time, or out of season, when the chance of infection is low. 153 Genetic control: The use of resistant varieties is one of the most common and important ways of controlling plant diseases. The aim is to prevent infection altogether or to slow disease development to avoid an epidemic. Growing many varieties in the same garden is one of the traditional ways this can be achieved. Each variety is different, and the differences can affect the progress of a disease. But genetic control is not always easy to obtain or sustainable. As food production has increased in response to growing human populations, there has been a trend towards fewer, higheryielding varieties. This has resulted in the appearance of new virulent strains of pathogens. The loss of crop varieties, and in sorne cases their wild relatives, has meant that resistance factors may no longer be available for plant breeders to use. To combat these problems, more attempts are being made to conserve crop genetic resources, and different plant breeding approaches are being explored. Today, many plant breeders try to produce plants with durable, or socalled horizontal, resistance. Often, this is controlled by several genes, each one of which may have only a small effect on the pathogen. The plants produced are not totally resistant or immune to a particular disease, but they are tolerant of infection. This means there is sorne loss in yield, but it is a reasonable priee to pay for lasting disease control. And, because infection still occurs, there is less likelihood that new strains will arise from within the pathogen population. On a different front, plant breeders are collaborating with molecular biologists, who are using modern technologies to manipulate DNA between species to produce varieties with novel kinds of disease resistance. Chemical control: A large number of pesticides are available to protect plants from infection, or to cure them once infected. Large increases in productivity can be expected if pesticides are used correctly, but for many diseases large gains occur only when chemical control measures are integrated with other methods, such as those discussed above. 154 Manufacturers' instructions should be scrupulously followed when pesticides are used. This includes applying the suggested dosage, as overapplication can damage plant tissues and reduce yields. The frequency of application is also important. And for sorne products, manufacturers suggest a limit on the number of applications per crop. Too frequent use may promote the very opposite of what is required: control may be lost because strains of the pathogen may develop that are resistant to the pesticide. As a further precaution against this, many systemic chemicals are used with proteetant products, either in combination or alternately. The manufacturers' instructions should also be consulted if it is intended to mix fungicides with insecticides. In many cases, they are not compatible. The correct use of pesticides is also concerned with safety to the user and the environment. Many pesticides are poisonous to humans, birds, fish and many beneficial insects. Users should wear protective clothing, avoid chemical drift and ensure that left-over or unwanted chemicals are disposed of safely. Stocks of pesticides should be kept in a secure place. Each pesticide cornes with notes on these aspects, and they should be read carefully and followed in detail. Most Pacific Island countries have legislation controlling the import of pesticides through registration procedures. The products which are allowed entry. and in sorne cases their specifie uses, have been considered on the basis of efficacy and safety. Often countries rely on information generated for product registration in Australia, the European Union, New Zealand and the USA to arrive at their decisions. For this reason, the chemicals recommended in this chapter are registered for use on the same crops in Australia, New Zealand or the UK. Where countries need specialist advice on, for instance, environmental issues and pesticide use, they can obtain it from the South Pacifie Commission or the South Pacifie Regional Environment Programme. The various pesticides recommended in this chapter are sold commercially under different names which can be found in Agricultural Chemicals Book IV, Fungicides; European Directory ofAgrochemical Products, Volume I-Fungicides; The UK Pesticide Guide; The Pesticides Manual, UK; New Zealand Agrochemical Manual; and PeskemAustralian Directory ofRegistered Pesticides and their Uses. Users can seek advice from suppliers of the products available 10caIly, as weIl as from their agriculture extension services. Tl- A CID 0 VORAX AVENAE subsp. CITRULLI - Citrullus lanatus Crop rotation is important. Cucurbits should not be planted on the land where the pathogen has been identified for at least two years. Ensure that seed is certified free from the bacterium. For chemical control: copper fungicides if symptoms are detected early in the growing season. T2 - AECIDIUM FRAGIFORME - Agathis spp. No treatment known. T3 - ALBUGO CANDIDA - Brassica chinensis, Raphanus sativus Cultural control measures include the removal or deep burial of crop debris and volunteer plants, and crop rotation with non-cruciferous plants. Chinese cabbage varieties are susceptible. The resistance of other cabbages and radish is determined by a single dominant gene and may not be reliable. For chemical control: chlorothalonil plus metalaxyl, copper hydroxide, mancozeb, mancozeb plus metalaxyl, or zineb. T4 - ALBUGO /POMOEAE-AQUATICAE - Ipomoea aquatica Cultural control measures include removal or deep burial of crop debris and volunteer plants. Chemical control is unlikely to be required, but if needed: chlorothalonil plus metalaxyl, copper hydroxide, mancozeb, mancozeb plus metalaxyl, or zineb. T5 - ALTERNARIA ALTERNATA - Passiflora edulis; ALTERNARIA PASSIFLORAE - Passiflora edulis, Passiflora quadrangularis Yellow passionfruit is more resistant to infection from A. altemata, whereas purple passionfruit and hybrids between the two are very susceptible. For chemical control: copper oxychloride, copper oxychloride plus zineb, iprodione, mancozeb or propineb. Coverage of the foliage can be assisted by pruning dead or weak parts of the vines. T6 - ALTERNARIA BRASSICICOLA - Brassica oleracea var. capitata Cultural control measures include the removal of the remains of the previous crop, removal of cruciferous weeds, and crop rotation. The fungus is seedborne, and seed should be treated with hot water (SOO-S6°C for 10-20 min). For chemical control: copper oxychloride plus zineb, mancozeb or zineb. It is likely that control procedures for bacterial black rot, Xanthomonas campestris pv. campestris, will also control Altemaria leaf spot. T7 -ALTERNARIA DAUCI - Daucus carota; ALTERNARIA SOLANI - Lycopersicon esculentum, Solanum tuberosum; ALTERNARIA RADICINA - Daucus carota Cultural control measures include the removal of plant trash left from the previous crop, and crop rotation. Seed treatment is very important for carrot and tomato (soak in thiram or iprodione for 24 h, or in mixtures, e.g. iprodione plus metalaxyl plus thiabendazole, metalaxyl plus thiabendazole, or thiabendazole plus thiram). Grow tomato seedlings in 155 soil-Iess mixes or pasteurised soil. The following tomato varieties are reportedly partially resistant: India River, Manapal, Floradel, Floralou, MH-I, Tropic, Strobelee, Floradade. The following Australian potato varieties are partially resistant: Sequoia and Kurrel. Kennebec and Pontiac are highly susceptible. For chemical control: (a) carrot: copper hydroxide, copper oxychloride, mancozeb, metiram or zineb; Cb) potato: chlorothalonil, copper hydroxide, copper oxychloride, iprodione, mancozeb, maneb plus zineb, metiram, propineb or zineb; and (c) tomato: chlorothalonil, copper hydroxide, copper oxide, copper oxychloride plus zineb, iprodione, mancozeb, maneb plus zineb, metiram, propineb or zineb. T8 - ALTERNARIA PORRI - Allium porrum Cultural control measures include the removal of trash from the previous crop, and the improvement of plant vigour by providing adequate water and applications of organic or chemical fertilizers. In Kenya, the leek varieties Red Creole and Yellow Creole are reported as highly resistant. whereas Mexican and Burgundy Red are less so. For chemical control: benalaxyl plus mancozeb, chlorothalonil, copper hydroxide, mancozeb, mancozeb plus metalaxyl, or zineb plus metalaxyl. T9 -ASPERGILLUS FLAVUS - Cocos nucifera Rapid and complete drying techniques must be used after harvest in order to limit the spread of the fungus which produces a toxin that is highly dangerous to animal and human health. Storage conditions should be dry and cool. Seed of pean ut, maize or onion for sowing can be treated with benomyl or thiram. TIO - ASPERGILLUS NIGER - Allium sativum Usually saprophytic, but important as a post-harvest mould ofmaize and copra. Rotate onions with other crops, and ensure that storage conditions for the bulbs are dry and cool. 156 Tll- ATHELIA ROLFS/l - Arachis hypogaea, Daucus carota, Lycopersicon esculentum Cultural control methods are important, including the removal of plant remains and/or their deep burial before planting; crop rotations; and, in sorne crops, reducing plant density. Repeated deep tilling may help to reduce the number of sclerotia to levels where infection is no longer possible. The fungus has a very wide host range and crop rotation is not a practical method of control, although bananas appear resistant to attack and maize and cabbages are little affected. Applications of calcium nitrate or urea, or of calcium, nitrogen or ammonium bicarbonate significantly reduce the intensity of outbreaks in contaminated fields. Treating the soil with frequent applications of white coral sand may be beneficial, especially if applied together with well-decomposed manure. Black plastic mulch can reduce disease incidence by preventing the sclerotia from infecting plant stems and lower leaves. Biological control using Trichoderma harzianum or T. viride is still under investigation. For chemical control: quintozene, or fumigate the soil with metam-sodium or methyl bromide. Tl2 - BALANOPHORA FUNGOSA - Hibiscus rosa-sinensis Regular physical removal of the parasitic plant is the only method of control. Tl3 - BANANA BUNCHY TOP NANAVIRUS - Musa sp. The virus is transmitted by Pentalonia nigronervosa, an aphid specifie to Musa sp. It can also be spread by planting infected suckers. Only healthy planting material should be used, taken from nurseries where it is known that the plants are free from the disease. If suckers are taken directly from plantations, they should be taken only from plots free of symptoms of the disease for the previous two years. Regular field surveys are necessary to detect infected plants. Once found, they should be removed immediately, but only after the plants, including the suckers, have been thoroughly treated. Kerosene, mineraI oil or conventional insecticides, such as malathion, demeton-S-methyl, dimethoate or monocrotophos, can be used to destroy the aphids. When removing the plants, ensure that the entire mat is dug out to prevent regrowth of diseased suckers. There are no known resistant commercial banana cultivars and virus resistance is being genetically engineered in several countries including Australia. See SPC Plant Protection Leaflet No. 2 for further details on this pathogen and its control. Tl4 - BANANA STREAK BADNAVIRUS - Musa sp. The virus, which exists as a number of strains, occurs in bananas throughout the world and is also found in sugarcane. It is thought to be endemic in the variety Mysore, and is frequently seen on Cavendish bananas. It is transmitted by mealybugs in a semi-persistent manner. It is unlikely to be transmitted on cutting tools or by other mechanical means. The only method of control is to eradicate diseased plants and to use virus-free planting material. The virus is not eliminated by shoot-tip culture. As the virus can occur in plants without causing symptoms, plants in quarantine should be kept under observation for at least nine months. Tl5 - BIPOLARIS INCURVATA - Cocos nucifera Applications of phosphorus and potassium fertilisers increase the resistance of seedlings to infection. For chemical control: chlorothalonil, copper hydroxide, copper oxychloride, iprodione, mancozeb or zineb. Tl6 - BLACKEYE COWPEA MOSAIC POTYVIRUS - Vigna unguiculata ssp. sesquipedalis Use seed certified free from the virus and in cases where infection is low, remove affected plants as soon as symptoms are seen. Avoid planting near established fields that might be a source of the virus. Tl7 - BLOSSOM-END ROT - Lycopersicon esculentum This physiological disorder occurs where heavy rains follow a drought, temperatures are unusually high, or plants have underdeveloped root systems in heavy clay soils. Treatment with a solution of calcium chloride as soon as the first symptoms appear may be beneficial. Soil fertility should be checked and a balanced fertilizer applied, if needed. The application of lime to acid soils may be beneficial. Tl8 - BREMIA LACTUCAE - Lactuca sativa Development of this pathogen is favoured by excessive moisture (rain or irrigation). Plant debris should be removed or dug deeply into the soil after harvest. Many different strains have been recorded and this makes breeding for resistance difficult. The Florida variety PL 49015 is resistant as are (to a lesser extent) the Ithaca varieties, Mesa 659 and Iceberg. The variety Vanguard 75 has a dominant gene for resistance to many different isolates. For chemical control: copper hydroxide, copper oxychloride, mancozeb, mancozeb plus metalaxyl, metiram, or propineb. Treatment with metalaxyl alone is effective, but repeated use can lead to the development of resistant strains. Tl9 - BROWN HEART - Apium graveolens This is a physiological disorder often observed in light soils and linked to boron deficiency. The disorder is most marked when fertilizer rich in nitrogen is used. T20 - CADANG-CADANG-LIKE VIROID - Elaeis guineensis There is no method of treating palms once they are infected, but it is important that they be removed from the plantation as soon as they are diagnosed, as there is evidence that the viroid may spread from them to adjacent healthy palms. 157 T21- CASSAVA GREEN MOTTLE NEPOVIRUS - Manihot esculenta Cultural control measures are important, including the removal of infected plants and the selection of cuttings from plants which appear free from symptoms. T22 - CASSYTHA FILIFORM/S - Pinus caribaea Regular physical removal of the parasitic plant is the only method of control. This is not always easy to do as the seeds remain viable in the soil for several years. T23 - CEPHALEUROS VIRESCENS - Persea americana The presence of this alga is often linked to poor cultural conditions, such as excessive or too little shade, mineraI deficiencies and poor drainage. If these conditions are corrected, control is usually obtained. T24 - CERATOCYSTIS PARADOXA - Ananas comosus, Saccharum officinarum Careful handling of banana and pineapple fruit is important to avoid damage which may allow entry of this pathogen. Minimising root and trunk wounds on coconut will also reduce the risks of infection. Strict hygiene should be maintained in commercial packing sheds. In particular, diseased leaves and rejected fruit should be collected frequently and destroyed. Planting material of pineapple should be airdried, and that of sugarcane cut from younger parts of the cane, with at least three nodes. For chemical control, treat fruit or planting setts with fungicides: (a) pineapple: dip the base of the fruit in benomyl, prochloraz or triadimefon; (b) banana: dip the fruit in benomyl, carbendazim or thiabendazole; (c) sugarcane: dip the setts in benomyl, carbendazim, flusilazole, prochloraz, propiconazole or triadimefon. On coconuts, minor infections can be treated by cutting out and applying benomyl and wood preservative, but there is a chance of resistant strains developing. 158 T25 - CERCOSPORA CAPS/C/- Capsicum annuum; CERCOSPORA LONG/SS/MA - Lactuca sativa; CERCOSPORA TACCAE - Tacca leontopetaloides These are typically wet-weather pathogens and the most practical control measure is to use fungicides, although crop rotation and the removal of crop debris are likely to contribute to effective control. For chemical control: use thiram on sweet pepper seed; and for field crops, use benomyl, copper hydroxide, copper oxychloride, mancozeb or zineb. T26 - CERCOSPORA COFFE/COLA - Coffea arabica, Coffea canephora The pathogen can be very severe in the nursery, especially if there is insufficient shade, but it is rarely serious in the field as long as the correct cultural techniques are applied. For chemical control: benomyl, copper or dithiocarbamate fungicides. T27 - CERCOSPORA IPOMOEAE - Ipomoea aquatica The pathogen rarely causes a disease which warrants control. If control measures are required on sweet potato, remove crop debris after harvest, and practise crop rotation. T28 - CEREBELLA ANDROPOGON/S - Paspalum dilatatum Often mistaken for smut, this pathogen is of little importance and does not require control. T29 - CLADOSPOR/UM COLOCAS/AE - Colocasia esculenta Crop rotation and disposaI of plant remains give good control. The disease attacks older leaves, and probably has little impact on yield, so chemical control measures are not warranted. T30 - COCHLIOBOLUS HETEROSTROPHUS - Zea mays Cultural control measures involve destroying crop residues and volunteer plants. Tolerant varieties have been bred against the various strains of the fungus. Against strain T, use maize with normal cytoplasm; against strain 0, use varieties with a non-cytoplasmic dominant gene. Seedbome infections can be controlled by hot air (54°-55°C for 17 min), or with a mixture of thiram plus carboxin. For chemical control of field crops, if warranted, use mancozeb. T31- COCONUT FOLIAR DECAY NANAVIRUS - Cocos nucifera The virus is spread by Myndus taffini which breeds on the roots of Hibiscus tiliaceus and in the adult stage migrates to coconut palms. Coconut varieties differ in tolerance to the virus, with both Vanuatu tall and dwarf varieties (and their hybrids) showing resistance. Most introduced varieties are susceptible, but there are considerable differences between them. Malayan Dwarf varieties are very susceptible. T32 - COCONUT TINANGAJA VIROID - Cocos nucifera This is an important pathogen of coconuts and one of quarantine concem where it is not yet present. The viroid is known only from Guam, but is related to cadang-cadang viroid found in coconuts in the Philippines. There is no known control, although there is sorne evidence that the variety Javanica Red Dwarf is more tolerant than other taU or dwarf varieties. T33 - COLEOSPORIUM PLUMERIAE - PIumeria spp. If defoliation occurs, it will be necessary to treat the trees with dithiocarbamate or systemic fungicides, e.g. bitertanol or oxycarboxin. T34 - COLLETOTRICHUM CAPSICI - Capsicum annuum; COLLETOTRICHUM CIRCINANS - Allium cepa Cultural control measures are important, especially the destruction of plant remains from previous crops. Seed treatment of sweet pepper is important, and benomyl or thiabendazole plus thiram can be used. Bulbs of onion should be stored under cool, dry conditions to prevent infection from spores carried on the outside at harvest. Brown-skinned onions are resistant to smudge. For chemical control of foliar infections: chlorothalonil. T35 - COLLETOTRICHUM LlNDEMUTHIANUM - Lupinus aIbus, Lupinus angustifolius Cultural control measures include the destruction of plant trash from previous crops and crop rotations of 2-3 years. Intercropping maize and French bean significantly reduces losses caused by this pathogen. Seed treatment is important and benomyl, thiabendazole plus thiram, or thiram can be used. Altematively, use certified or approved seed. For chemical control on field crops: mancozeb, metiram or zineb. T36 - COLLETOTRICHUM ORBICULARE - Cucumis meIo, Citrullus Ianatus; COLLETOTRICHUM SP. - Momordica charantia Cultural control measures include crop rotation, ensuring good soil drainage, and the destruction of wild cucurbits. The cucumber varieties Calico, Calypso and Marketer are resistant. Seed treatment is important, and thiram can be used. For chemical control of field crops: benalaxyl plus mancozeb, benomyl, copper oxychloride, mancozeb, mancozeb plus metalaxyl, or propineb. T37 - COLOCASIA BOBONE DISEASE (?) RHABDOVIRUS CoIocasia escuIenta The virus is present only in Papua New Guinea and Solomon Islands. It occurs alone in plants and causes bobone or with dasheen bacilliform (?) badnavirus resulting in alomae. As such, it is of major quarantine importance to countries yet free from it. If countries wish to import material it should be as pathogen-tested plants, preferably from regional tissue culture laboratories. Control of the virus is difficult, as most plants 159 are infected. Because of this, roguing plants as they show symptoms is not a practical method of control. In any case, plants invariably recover to produce corros of acceptable size. Varietal differences exist. The virus causes severe symptoms only in a few so-called 'female' varieties; 'male' taro are tolerant, showing only small dark green distorted areas on the leaves. 'Male' taro, however, are susceptible to alomae, whereas 'female' taro are resistant. For chemical control against the planthopper vector, Tarophagus proserpina: acephate, dimethoate, endosulfan or malathion. The mirid egg-predator, Cyrtorhinus fulvus, has been used to control planthopper populations. T38 - COLOCASIA BOBONE DISEASE (?) RHABDOVIRUS and DASHEEN BACILLIFORM (?) BADNAVIRUS - Colocasia esculenta Where these two viruses occur together in taro (Papua New Guinea and Solomon Islands) they cause alomae, a lethal disease. Dasheen bacilliform (?) badnavirus is widely distributed in Pacific Island countries, but Colocasia bobone disease (?) rhabdovirus (alomae strain) is not, and it is of major quarantine importance to countries yet free from it. If countries wish to import material it should be as pathogen-tested plants, preferably from regional tissue culture laboratories. Cultural control measures include the destruction of diseased plants as soon as symptoms appear and siting new plantings away from older crops, especially those already infected. Varieties differ in their resistance to the virus complex, but those that are tolerant, so-called 'female' taro, are susceptible ta bobone caused by infection from Colocasia bobone disease (?) rhabdovirus. A programme to breed taro with greater tolerance to the virus complex exists in Papua New Guinea. For chemical control against the planthopper vector, Tarophagus proserpina: acephate, dimethoate, endosulfan or malathion. See SPC Plant Protection Leaflet No. 8 for further details on these pathogens and their control 160 T39 - COLOCASIA BOBONE DISEASE (?) RHABDOVIRUS (FIJI STRAIN) - Colocasia esculenta Plants infected with the mild strain recover from infection and as there is no indication that yield is affected, control measures are not warranted. T40 - CORDANA MUSAE - Musa sp. Usually of minor importance on Cavendish bananas and control measures are not warranted, but it can defoliate plantains. For chemical control: mancozeb, petroleum oil, propiconazole or zineb. Do not use oil on plantains, since it is phytotoxic. Fungicides used for black Sigatoka control are effective. T41 - CORTlCIUM PENIClLLATUM - Cocos nucifera If practical, avoid growing coconuts under excessive shade, and cut out and bum affected leaves. It is unusual for this pathogen to cause a disease of importance. T42 - CORYNESPORA CASSllCOLA - Carica papaya, Cucumis sativus Control is generally not warranted on papaya. On cucumber, symptoms can be severe. Destroy crop debris after harvest. Treat seed with thiram. For chemical control: benomyl, copper fungicides or mancozeb. T43 - CUCUMBER MOSAIC CUCUMOVIRUS - Musa sp., Piper methysticum This is a minor pathogen of banana and control measures are not warranted. On kava, the disease is a major concem. Cultural control measures are important, including the selection of propagating material from plantings free from dieback, and the removal of infected plants immediately symptoms are seen. Aphids are vectors of the virus, but insecticides are not effective in preventing the spread of the disease. T44 - CURVULARIA ISCHAEMI - Ischaemum indicum Although the host is an important pasture grass, control is impractical, and as yet there no indication of the damage that the fungus does to this grass. T48 - DEIGHTONIELLA PAPUANA - Saccharum officinarum No control is warranted as the damage caused by this pathogen is not thought to affect cane yields. T45 - DASHEEN MOSAIC POTYVIRUS - Colocasia esculenta, Xanthosoma sagittifolium This virus is spread by aphids and in suckers used for propagation. There is no evidence that the virus reduces corm yield and control measures are not warranted. See SPC Plant Protection Leaflet No. 10 for further details on this pathogen and its control. T49 - ELSINOE BATATAS - Ipomoea batatas Cultural control measures include: crop rotation, selection of propagating material free from the disease or, if this is not possible, the production of disease-free cuttings from tubers planted in nursery beds. Many varieties with tolerance to scab exist in Papua New Guinea and Solomon Islands and, in Tonga, varieties have been bred for resistance. Many of these are available as pathogen-tested tissue cultures from the laboratories of regional organisations. For chemical control: mancozeb. See SPC Plant Protection Leaflet No. 24 for further details on this pathogen and its control. T46 - DASHEEN MOSAIC POTYVIRUS (SEVERE STRAIN) Colocasia esculenta The virus has been reported only from French Polynesia. As such, it is of major quarantine importance to other countries in the region. If countries wish to import material it should be as pathogen-tested plants, preferably from regional tissue culture laboratories. Plants should be removed as soon as symptoms appear and burnt or buried. It would be beneficial if the plants were first sprayed with an insecticide (acephate, demeton-Smethyl, dimethoate or malathion) to destroy aphid vectors which might otherwise spread the virus. T47 - DIDYMELLA BRYONIAE - Citrullus lanatus, Cucumis sativus Cultural control measures include the removal or deep burial of crop debris, and crop rotation. After crops of cucurbits, plant beans, cabbage, onion or tomato. To prevent seedborne infections, treat seed with thiram. For chemical control of field crops: benomyl plus mancozeb, copper oxychloride, mancozeb, mancozeb plus metalaxyl, or propineb plus metalaxyl. T50 - ELSINOE FAWCETTII - Citrus spp. In orchards, sanitation is important, including the removal of infected fruit and the pruning of branches before new flushes develop. The disease can be serious in nurseries, particularly on rough lemon seedlings. For chemical control: copper oxychloride plus white oil, copper oxychloride plus zineb, or zineb. T51 - ELSINOE SACCHARI - Saccharum officinarum No control is warranted as the damage caused by this pathogen is not thought to affect cane yields. T52 - ERWINIA SPP. - Brassica oleracea var. capitata, Solanum tuberosum Cultural control measures are important. For cabbages, remove infected plants as they occur, remove or deeply bury plant remains after harvest, and practise crop rotation with beans, cucumber and tomato. Avoid harvesting when crops are wet, and clean or sterilise the knife used in harvesting. For potatoes, use certified 'seed'. Cultural measures are also 161 important, inc1uding the regular disinfection of tools used for cutting and handling tubers (use, e.g. chlorine as sodium hypochlorite); avoiding wounding the tubers; and draining the fields to avoid waterlogging. Large applications of nitrogenous fertilizers reduce the damage caused by these pathogens, but may increase the incidence of bacterial wilt on potato caused by Pseudomonas solanacearum. Tubers should not be washed after harvest and before storage, and they should be stored under cool, well-ventilated conditions. T56 - FUSARIUM OXYSPORUM - Vanilla fragrans Stems and leaf infections are best controlled by applications of fungicides: benomyl, captan, carbendazim, mancozeb or thiophanatemethyl. If root infections occur, as reported for F. oxysporum f. sp. vanillae, avoid cultivation around the roots; ensure the correct level of shade to avoid water stress; apply mulch, especially during the dry season to retain soil moisture; adjust pollination to avoid overbearing; loop vines to stimulate root production and the replacement of those destroyed by infection; and avoid planting on waterlogged soil. T53 - ERWINIA SPP. - Musa sp. Cultural control measures are important: remove and destroy plants with the disease, by either burying or buming, as soon as symptoms appear, and select only healthy planting material. T54 - FULVIA FULVA - Lycopersicon esculentum Heavily infected lower leaves should be removed as soon as the first three or four fruit trusses have been picked. Crop residues should be bumt. Tolerant varieties have been bred, but there are several races of the fungus and varieties may not be resistant to them aIl. For chemical control: carbendazim plus chlorothalonil plus sulphur, chlorothalonil or propineb. Copper fungicides can be used, but they may harden the foliage. See SPC Plant Protection Leaflet No. 15 for further details on this pathogen and its control. T55 - FUSARIUM OXYSPORUM - Anthurium andreanum, Capsicum annuum; FUSARIUM OXYSPORUM f. sp. GLADIOLI Gladiolus sp. Applications of boron or iron reduce the incidence of attack by promoting internaI resistance mechanisms. Good control can also be obtained by applying calcium nitrate and potassium chloride between the rows. For chemical control: benomyl, carbendazim, iprodione, prochloraz or thiabendazole. Where plants are propagated by seeds, biological control is a possibility with the application of Trichoderma harzianum or T. koningii. 162 T57 - FUSARIUM OXYSPORUM f. sp. COFFEAE - Coffea arabica, Coffea canephora; FUSARIUM OXYSPORUM - Prunus persica Reduce soil acidity by liming. Disinfect tools and implements with methylated spirits. For chemical control: captan or captafol until the bark has matured. T58 - FUSARIUM OXYSPORUM f. sp. CUBENSE - Musa sp. An important disease of quarantine concern to those countries yet free from the pathogen. Within the Pacific Islands, it is present only in Fiji, Guam and Papua New Guinea. If countries wish to import material it should be as pathogen-tested plants, preferably from regional tissue culture laboratories. There are several races, with Race 4 of most concern as it attacks Cavendish varieties which were previously resistant to the pathogen. Cultural control measures are extremely important, including: avoiding poorly drained soils or sites that receive surface water from diseased plantations; avoiding discarding bunch stalks in areas above existing plantations; and, if the bananas are irrigated, ensuring that the source of water is not from below the infected area, or if it is, that a floating intake is used, as the spores sink after a few days. Knives used in cultural practices should be disinfected with formaldehyde, methylated spirits or sodium hypochlorite, and efforts made to prevent the movement of soil from infected to healthy plantations on ladders, vehicles and people (dip footwear in a copper fungicide/methylated spirit mixture). Where outbreaks occur, diseased plants, and their immediate neighbours, should be destroyed as soon as possible by injection of herbicide, and the remains dug out, bagged, and carefully removed from the plantation and bumt. If only a few plants are affected, treat the diseased stools with basamid and coyer with a plastic sheet. Resistance to Race 4 is being sought in Australia. T59 - FUSAR/UM OXYSPORUM f. sp. GERBERAE - Gerbera sp. The fungus can survive in the soil for over 10 years. Calcium deficiency facilitates survival, especially when this element is unavailable due to high magnesium or phosphorus concentrations. Seedbome transmission is a possibility and seed should be treated with thiram. In the greenhouse, disinfect the soil with methyl bromide. In the field, benzimidazole fungicides are effective if used before the beginning of an outbreak. Resistant varieties exist, but nematode infestations considerably reduce their effectiveness. T60 - GANODERMA APPLANATUM - Casuarina equisetifolia Infected stumps and roots should be removed, the remains bumt and the soil disinfected with formaldehyde if necessary. T61- G/BBERELLA FUi/KORO/ - T62 - GLOMERELLA C/NGULATA - Actinidia deliciosa, Agathis spp., Annona squamosa, Anthurium andreanum, Apium graveolens, Aranda sp., Carica papaya, Citrus spp., Coffea arabica, Coffea canephora, Dioscorea alata, Mangifera indica, Manihot esculenta, Passiflora edulis, Persea americana, Phaseolus vulgaris, Psidium guajava, Vanda sp., Vanilla fragrans On tree crops, remove dead twigs and branches before flowering. Varietal resistance occurs in sorne crops, e.g. the yams, Belep, Kinabayo, Oriental and Plimbite. The papaya variety Sunrise Solo is more resistant than Kapoho Solo. For chemical control of tree, field and vegetable crops, treat regularly using copper hydroxide, copper oxychloride, mancozeb or mancozeb plus prochloraz. To protect the flowers, treatrnents on mangoes should commence as soon as the spikes appear. On omamentals, use chlorothalonil, copper oxychloride, mancozeb or prochloraz. Resistances to benomyl, thiabendazole and thiophanate-methyl have appeared. After harvest, mangoes can be dipped in benomyl (52°C for 5 min), and then stored at 10°_12°C. Ahot-water dip (48°C for 20 min) is effective for control of the pathogen on papaya. On avocado, post-harvest chemical treatrnent of fruit, and controlled temperature (l6°-18°C) during ripening, and subsequent storage (2°-4°C), are critical to the production of commercial-grade fruit. See SPC Plant Protection Leaflet No. 12 for further details on this pathogen and its control on yam. T63 - GLOMERELLA TUCUMANENS/S - Saccharum officinarum Control can be obtained through the use of resistant varieties. Zea mays Drying the kemels before storage to a maximum moisture content of 12% prevents the development of the fungus. Resistant varieties are available. For chemical control: benomyl or captan for seed used for sowing. T64 - GOPLANA AUSTRALIS - Dioscorea spp. No control is warranted as the damage caused by this pathogen is not thought to affect tuber yields. 163 T65 - GOPLANA DIOSCOREAE - Dioscorea spp. No control is warranted, as the damage caused by this pathogen is not thought to affect tuber yields. T66 - GUIGNARDIA DIOSCOREAE - Dioscorea spp. No control is warranted, as damage by this pathogen is not thought to affect tuber yields. It is likely that varieties differ in susceptibility to this pathogen. T67 - GUIGNARDIA MUSAE - Musa sp. The disease is not of economic importance on the Ieaves, but infected leaves may act as sources of spores for fruit infections. Destroy infected leaves. Varieties differ in their susceptibility to infection, with Cavendish being resistant. In Hawaii, growers place a paper bag over the newly emerged bunch to prevent spores from the leaves reaching the fruit. For chemical control: dithiocarbamate fungicides. Fungicides used for the control of black Sigatoka will also be effective. T68 - HEMILEIA VASTATRIX - Coffea arabica, Coffea canephora Resistant lines are available, e.g. Catimor selections derived from the Timor hybrid. Chemical control is possible and copper fungicides are effective. The timing of treatments should be closely linked to the frequency and intensity of rainfaii. Systemic fungicides may be applied once 20% of the foliage has become infected. Use oxycarboxin or triadimefon. T69 - HIRSCHMANNIELLA MIT/CAUSA - Colocasia esculenta Cultural control measures include crop rotation and the use of clean planting materiai. OId Ieaves, roots and soil should be removed and the corm piece inspected to ensure freedom from rots. Varieties differ in their susceptibility to infection. Resistance to the nematode has been detected in wild taro in Solomon Islands, and in hybrids between this and local 164 cultivars. Giant swamp taro is resistant to infection. T70 - INTERNAL BROWNING - Malus x domestica The disorder is due to storage of fruit at excessively low temperatures, but still above freezing point. Apple varieties show widely varying degrees of susceptibiIity. T71- LASIODIPLODIA THEOBROMAE - Artocarpus altilis, Persea americana Cultural control measures are important. In avocado, dead Ieaves, twigs and branches should be removed from the canopy before flowering. Efforts should be made to prevent or protect wounds through which the fungus can enter and infect. In cocoa and other trees, pruning wounds can be sealed with tar mixed with copper fungicides; collar rot of passionfruit associated with the tunnelling of the beetle, Elytroteinus subtruncatus, can be treated with insecticides or applications of flowable formulations of thiram; and banana fruit can be dipped in benomyl, carbendazim or thiabendazole to prevent crown and fingertip rots. In papaya, hot-water dips as for anthracnose control (T62) can be effective. See also comments on handling avocado at harvest. For chemical control in avocado: benomyl or thiabendazole. Resistance to these fungicides has been recorded, and imazalil may be used as an alternative. T72 - LETTUCE MOSAIC POTYVIRUS - Lactuca sativa The virus is spread by aphids and is also seedborne. Seeds should he certified free from infection. The remains of the crop should be destroyed as soon as possible after harvest. Lettuce varieties show differing degrees of susceptibiIity, with cos lettuces being more resistant than cabbage types. T73 - LEVEILLULA TAURICA - Lycopersicon esculentum Many different plants are hosts, so spores are available throughout the year. Certain crops are at risk when moisture levels are high (e.g. eggplant and sweet pepper), while others are only affected during dry conditions (e.g. tomato, lucerne and cotton). Crops at different growth stages should not be placed next to each other. For those crops which are at risk during dry conditions, sprinkler irrigation is recommended. For chemical control: sulphur-but this may cause burning of the leaves and fruit in dry weather-alternatively, benomyl, bupirimate or fenarimol. T74 - MAGNAPORTHE SALVINII - Oryza sativa It is during the cool season that infection from this pathogen is most serious, with overcast periods and light rain providing ideal conditions for its development. Crop residues should be burnt or removed. Resistant varieties are available. Seed treatments are important, and TCMTB is used. For chemical control in established crops: copper fungicides, applied between the time of stem and ear formation. T75 - MAIZE MOSAIC RHABDOVIRUS - Zea mays Cultural control measures include crop rotation and the elimination of grasses that are alternative hosts of the virus from within and around the planting. Varieties differ in their reaction to infection. For chemical control against the planthopper vector, Peregrinus maidis, use insecticides: acephate, malathion or dimethoate. T76 - MARASMIELLUS ALBOFUSCUS - Cocos nucifera Usually not important and no control measures are warranted, although there have been no studies to verfiy this. T77 - MARASMIELLUS COCOPHILUS - Cocos nucifera Grasses are alternative hosts of the fungus and in nurseries they should be controlled. The fungus is seedborne and dipping pared coconuts in phenyl mercury acetate is likely to give control. Reassessment of lethal bole rot previously attributed to this pathogen in Kenya and Tanzania has cast doubt that Marasmiellus is the cause. In Solomon Islands, the only other country where the fungus has been reported, a quarantine embargo on the movement of coconuts from the island where the fungus was found, to other parts of the country, is no longer maintained. T78 - MARASMIELLUS INODERMA - Cocos nucifera, Musa sp.; MARASMIELLUS STENOPHYLLUS - Colocasia esculenta Infections in coconut occur while the nuts are still on the palm and as such they are difficult to prevent. Dips in a variety of fungicides have not given consistent and reliable results. Best control has been obtained with phenyl mercury acetate, but less potentially hazardous fungicides, e.g. benodanil, may also be effective. Local varieties are mostly resistant to attack. Infections on taro are not sufficiently serious to warrant control measures, although removal of diseased plants should be carried out to limit spread. On banana, the removal of infected plants and the use of fertilizers to promote vigorous growth are measures that may be effective against this fungus which is generally difficult to control. Planting material should be selected carefully to ensure it is free of the pathogens. T79 - MELOIDOGYNE SPP. - Phaseolus vulgaris Root-knot nematodes often cause severe infections on susceptible crops and a number of control measures are often necessary to bring about control. Cultural control measures are important. Repeated cultivation kills nematodes in the upper layers of the soil by exposing them to heating and drying by the sun. This is a good method of nematode control in seedbeds. Crops should be removed and destroyed by burning or burying as soon as harvest is over to prevent the nematodes from spreading into 165 the soil as the plants decay. At least a year should separate susceptible crops, as the eggs can remain viable for several months. Fallows may also be beneficial, with weed-free fallows of 4-6 months usually sufficient to reduce populations considerably. Where it is not acceptable for the land to remain idle for long periods, resistant coyer crops can also be planted, e.g. green panic (Panicum maximum var. trichoglume) and siratro (Macroptilium atropurpureum). Resistant varieties are available for many of the crops attacked by nematodes. Peanuts are generally resistant to ail the races in the Pacific Islands, and so is the yellow passionfruit. Varieties of bean, cassava, cowpea, sweet potato, tomato and taro are also available with resistance. Vegetative planting material of banana, ginger, potato and yam, without signs of infection, can be treated with hot water at 51°C for 10 min. For chemical control: carbofuran, ethoprophos, fenamiphos, oxamyl, and the fumigants, dazomet and methyl bromide. To be effective, chemical treatments should be combined with the cultural techniques described above. T80 - CAPNODIUM CITRI - Citrus spp. This non-pathogenic fungus develops on the surface of leaves in the sugary exudate of scale insects. Sometimes it grows profusely and restricts photosynthesis. Control is achieved by destroying the scale insects with insecticides (e.g. malathion plus white oil) and controlling ant populations which protect them. T81- MYCOSPHAERELLA ALOCASIAE - Alocasia macrorrhizos No control measures are required as the disease caused by this pathogen is unlikely to affect corm yield. T82 - MYCOSPHAERELLA BERKELEYI - Arachis hypogaea Cultural control measures include the removal or burial of plant remains, and crop rotation. Varieties differ in susceptibility to infection, and there 166 is evidence of different pathogenic strains. For chemical control: benomyl, cyproconazole, mancozeb or propiconazole. The same fungicides will control early 1eaf spot. Resistance to benomyl may occur. T83 - MYCOSPHAERELLA FIJIENSIS - Musa sp. The pathogen has replaced M. musicola, the cause of yellow Sigatoka disease, in most Pacific Islands. It is more difficult to control. Cultivation practices which lower the humidity and increase ventilation in plantations will help to reduce infection. There is merit in removing diseased 1eaves, preventing excessive weed coyer and limiting sucker development. Soil fertility should be maintained and, if waterlogged, soils should be drained. Most banana varieties grown for export are susceptible, but sorne plantains have greater tolerance, maintaining at least four 1eaves until harvest. Pathogen-tested introductions from countries outside the region are under evaluation. For chemical control: oil-in-water emulsions plus benomyl, mancozeb, maneb, propiconazole (or flusilazol) plus mancozeb, or tridemorph. The repeated use of benomyl should be avoided because of the possible appearance of resistant strains. See SPC Plant Protection Leaflet No. 1 for further details on this pathogen and its control. T84 - MYCOSPHAERELLA HENNINGSII - Manihot esculenta Lowering the plant density will reduce the humidity within the plantation and reduce the incidence of infection. Varieties differ in resistance. For chemical control, if warranted: copper fungicides. T85 - MYCOSPHAERELLA MUSICOLA - Musa sp. Cultivation practices which lower the humidity and increase ventilation in plantations will help to reduce infection. These include improved drainage, removal of diseased leaves and the pruning of suckers. Varieties of the AAA group are very susceptible, whereas plantains, ABB and AAB, are more tolerant. For chemical control, petroleum oïl can be used. The disadvantage is that it is somewhat phytotoxic on plantain varieties if it is not applied properly (if the oil is of poor quality, it is used too frequently, or sprays are applied during hot, dry, sunny weather). Altematively, benomyl, chlorothalonil, copper oxide, mancozeb, propiconazole or zineb can be applied, in oil plus water emulsions. The repeated use of benomyl should be avoided because of the possible appearance of resistant strains. T86 - NEOJOHNSTONIA COLOCASIAE - Colocasia esculenta Although the pathogen can occasionally be severe on sorne plants and sorne varieties, it probably causes little yield loss, and no control measures are warranted. T87 - OIDIUM SPP.- Mangifera indica, Vigna unguiculata ssp. sesquipedalis Mango varieties differ in resistance to the pathogen. For chemical control: micronised sulphur, taking care, when using the powder form, to avoid buming the foliage by applying early in the moming, in the evening, or during overcast days. It is likely that benomyl, mancozeb or mancozeb plus prochloraz, used to control anthracnose, will also be effective for powdery rnildew control, if applied regularly during blossoming. For chemical control in beans: benomyl or sulphur. T88 - ONCOBASIDIUM THEOBROMAE - Theobroma cacao Cultural control measures are important; they include raising nursery stock away from diseased cocoa, and pruning trees to remove shoots at least 30 cm below discoloured vascular tissues. Varietal differences exist and their selection from amongst the Trinitario cocoa of Papua New Guinea during the epidemics of the 1960s has reduced the pathogen to minor importance. Amelonado is susceptible. Breeding for improved resistance continues in Papua New Guinea. T89 - PAPAYA RINGSPOT POTYVIRUS - Carica papaya The virus is of major quarantine importance where it is not yet present. Where it is established, it has proven difficult to control. Cultural control measures include the removal of infected plants within the crop, the elimination of wild and volunteer plants within and around the plantation, avoiding unnecessary movement of people and animaIs within the plantation, and ensuring that plants are spaced adequately to avoid leaves touching each other. Conventional breeding for resistance is being attempted, but has yet to produce fruit of acceptable quality. Sorne success has been achieved in Taiwan and Hawaii using mild strain resistance. Genetically engineered plants transformed with the coat protein gene of the virus have been produced in Hawaii. Attempts to control the spread of the pathogen by using insecticides to kill aphid vectors have not been effective. T90 - PASSIONFRUIT WOODINESS POTYVIRUS - Passiflora edulis The virus exists as several strains, which complicates control measures. It is important to ensure that propagating stock is free from infection. Nurseries and surrounding areas should be free of weeds, and plants should be protected against colonisation by aphids, which spread the virus. Cuttings taken from the field for propagation should be carefully selected from plantations free from the disease. Varieties differ in their tolerance to infection, with the purple passionfruit being particularly susceptible. Hybrids, P. edulis x P. edulis f.flavicarpa, are tolerant to most strains, but severe strains exist in Australia which cause considerable damage. A 'mild strain' of the virus has been used commercially. 167 T91- PELLICULARIA KOLEROGA - Coffea arabica, Coffea canephora Pruning and destruction of plant remains are the most effective methods of control. T92 - PENICILLIUM DIGITATUM, PENICILLIUM ITALICUM Citrus spp. Ensure that fruit are harvested carefully and not when wet from rain or dew. They should be cut rather than pulled from the tree, to avoid causing wounds. Strict hygiene should be maintained in commercial packing sheds. In particular, diseased leaves and rejected fruit should be frequently collected and destroyed. For chemical control: benomyl, carbendazim, guazatine, imazalil, thiabendazole or thiophanate methyl. There is the possibility of the development of strains resistant to benomyl. T93 - PERICONIA MANIHOT/COLA - Manihot esculenta No control measures are required, as the disease caused by this pathogen is unlikely to affect root yields. T94 - PERONOSCLEROSPORA SACCHARI - Zea mays Cultural control measures include the removal and destruction of infected plants as soon as symptoms appear, avoiding interplanting maize and sugarcane, and for sugarcane, the careful selection of healthy planting setts. The pathogen is usually of minor importance in maize, but is regarded as a threat to sugarcane, although most varieties grown commercially have resistance. For chemical control: metalaxyl for seed treatment of maize. T95 - PERONOSPORA PARASIT/CA - Brassica oleracea var. capitata The disease is often more important on seedlings than on established 168 plants. It is important to keep nurseries free from susceptible weeds and to destroy crop residues. Resistant varieties exist. For chemical control: chlorothalonil, copper hydroxide, maneb plus zineb, mancozeb plus metalaxyl, or zineb. Ensure that the under surface of leaves is weIl covered with fungicide. T96 - PESTALOT/OPSIS DISSEMINATA - Psidium guajava; PESTALOT/OPSIS PALMARUM - Cocos nucifera Improve growing conditions by applying fertilizer and, in coconut nurseries, decrease shade levels. For chemical control: chlorothalonil, copper oxychloride, mancozeb, maneb plus zineb, or zineb. T97 - PHAEOISARIOPSIS GRISEOLA - Phaseolus vulgaris The fungus survives in plant remains between crops and these should be destroyed or deeply buried after harvest. Resistant varieties are available (e.g. Redlands Greenleaf). Seedbome infections are a possibility and seed should be treated with thiram, or thiabendazole plus thiram. For chemical control on field-grown plants: mancozeb or benomyl. T98 - PHANEROCHAETE SALMONICOLOR - Citrus spp., Coffea arabica, Coffea canephora, Theobroma cacao Pruning and the reduction of shade levels are the two most important control measures. Affected branches should be pruned about 30 cm below the affected parts, removed from the plantation and bumt. For chemical control: copper oxychloride or tridemorph. Chemical control and pruning should be applied together. T99 - PHELLINUS LAMAENSIS - Coffea arabica, Coffea canephora Control measures are aimed at preventing the spread of the fungus from infected trees to others in the plantation. Infected trees should be dug out and removed, preferably bumt. This should be done as soon as symptoms appear. Afterwards, and if practical, a legume ground coyer should be established, as this will increase soil organisms antagonistic to Phellinus. It is important to inspect the base of the trunk and major roots of adjacent trees to check if they are infected. TIOO - PHELLINUS NOX/US - Artocarpus altilis, Cordia aIliodora, Theobroma cacao The pathogen is difficult to control. By the time symptoms are seen the root system has been extensively damaged and the fungus has invaded the collar region of the trunk. Occasionally, trees can be cured if diseased parts are removed immediately symptoms appear. If this is not the case, it is important to prevent tree-to-tree spread by removing the diseased tree, making sure to extract ail roots more than 2.5 cm diam. It is also good practice to expose the base of the trunk and major roots of adjacent trees to check if they are infected. In forestry situations, increased tree spacing, interplanting rows of susceptible trees with those that are more resistant, and delaying planting after clear-felling to allow time for complete decay of woody debris, are ail measures that have been considered. TIOI - PHOMA SPP. - Colocasia esculenta These pathogens have not been shown to reduce yields sufficiently to warrant control measures. Taro varieties differ in their susceptibility to shot-hole. In general, infection is more severe in the cooler months of the year. TI02 - PHYLLACHORA MUS/COLA - Musa sp. Cavendish varieties are resistant. Although sorne plantains are susceptible, damage is unlikely to reduce yield sufficiently to warrant control measures. TI03 - PHYTOPHTHORA COLOCAS/AE - Colocasia esculenta This is a disease of major quarantine importance to countries which are yet free from the pathogen. If countries wish to import material it should be as pathogen-tested plants, preferably from regional tissue culture laboratories. Cultural control measures are important, including: the regular removal of infected leaves, the avoidance of planting new crops adjacent to those that are already infected, using planting material free from infection, and using wider-than-traditional plant spacing. Diseasefree planting material can be obtained by removing ail but three or four of the youngest leaves and checking that the corm piece is free from rot. Dipping the planting material in chlorox, mancozeb, metalaxyl or potassium phosphonate is also recommended, but is probably not necessary if older leaf bases have been removed. Plants are being bred in Papua New Guinea and Solomon Islands for greater tolerance to the disease. For chemical control: copper oxide plus metalaxyl, copper oxychloride, mancozeb, mancozeb plus metalaxyl, or potassium phosphonate. Chemical control should be combined with roguing diseased leaves. See SPC Plant Protection Leaflet No. 3 for further details on this pathogen and its control. TI04 - PHYTOPHTHORA HEVEAE - Cocos nucifera; PHYTOPHTHORA PALM/VORA - Artocarpus altilis, Cocos nucifera, Theobroma cacao, Vanilla fragrans, Vanilla tahitensis Cultural techniques are important in the control of these pathogens, including the removal of weeds, adjustment of shade levels (cocoa and vanilla), the regular removal of diseased plant parts (chupons and pods of cocoa, fruit of papaya and breadfruit), and the use of a mulch to coyer the soil. It is important to establish plantings on well-drained land. For papaya, the virgin soil technique, i.e. taking soil from areas where papaya has never been grown and using it to fill the planting holes, has been used 169 to good effect in replant areas. Varietal resistance is important in cocoa, with tolerance in Amelonado and sorne Trinitario clones, whereas Criollo varieties are very susceptible. Differences also exist in the reaction of coconut varieties to infection. For chemical control: copper fungicides, copper oxide plus metalaxyl, mancozeb plus metalaxyl, or potassium phosphonate. The latter has been used successfully as a trunk injection for the control of black pod and canker in cocoa. See SPC Plant Protection Leaflet No. 7 for further details on this pathogen and its control. TIOS - PHYTOPHTHORA NICOTIANAE var. PARASITICA - Carica papaya, Citrus spp., Vanda sp. Cultural techniques are important in the control of this pathogen, including the removal of dead trees and fallen fruit, the choice of welldrained sites, avoiding damage to the collar region during weeding and other horticultural operations, and the use of ground covers or mulches. If detection is early, cankers on citrus can be scraped away and the wounds covered, initially, with the fungicides listed below and, later, with taro If the plantations are irrigated, it is important that water not touch the trunk. Varietal control is possible in citrus with the use of bitter orange rootstocks, but they are often susceptible to citrus tristeza closterovirus. Poncirus trifoliata rootstocks are relatively tolerant of Phytophthora infection. For chemical control: aluminium phosetyl, potassium phosphonate or mancozeb plus metalaxyl applied as a paint or spray to the trunk. For soil fumigation after the removal of dead trees: formaldehyde, methyl bromide or metam-sodium. TI06 - PHYTOPLASMA - Ipomoea batatas The pathogen is spread by the leafuopper, Orosius lotophagorum ryukyuensis, but more importantly through the use of cuttings taken from diseased plants. Destruction of diseased plants, careful selection of planting material and the removal of alternative hosts are all important control measures. Varietal resistance has not been reported. Introductions 170 of germplasm should be limited to plants derived from meristems and indexed for mycoplasma-like organisms and virus infections. For chemical control against insect vectors: acephate, carbaryl, dimethoate or malathion. See SPC Plant Protection Leaflet No. 19 for further details on this pathogen and its control. TI07 - PHYTOPLASMA -Lycopersicon esculentum, Solanum tuberosum Keep plantings and surrounding areas free from weeds. Remove infected plants as soon as symptoms are seen. For chemical control on tomato, against leafuopper, Orosius argentatus, vectors: dimethoate, endosulfan or malathion. TIOS - POTATO LEAFROLL LUTEOVIRUS - Solanum tuberosum Avoid growing crops next to potato or tomato plantings that are older and possibly infected with the virus. Remove weed hosts, such as Datura spp. and Physalis spp. Use certified seeds. For chemical control of aphid vectors: acephate, demeton-S-methyl, dimethoate, endosulfan or malathion. TI09 - PRATYLENCHUS COFFEAE - Dioscorea spp. Cultural control measures are important, including the careful selection of planting setts free of rot, and crop rotation. Tubers should be regularly inspected during storage and those with surface rots removed and eaten rather than kept for propagation. THO - PSEUDOCERCOSPORA ABELMOSCHI - Abelmoschus esculentus The pathogen is not considered to cause sufficient damage to warrant control measures. If blemish-free leaves are required, use benomyl, copper fungicides or mancozeb. Tllt - PSEUDOCERCOSPORA COLOCASIAE - Colocasia esculenta The pathogen is not considered to cause sufficient damage to warrant control. T112 - PSEUDOCERCOSPORA TIMORENSIS - Ipomoea batatas The pathogen usually infects older leaves and, as it is unlikely that it reduces root yield, control measures are not considered necessary. Varieties are likely to differ in their susceptibility to infection. T113 - PSEUDOEPICOCCUM COCOS - Cocos nucifera The disease is usually present on older leaves and as such is not thought likely to reduce yields. If control measures are warranted, improve nutrition and growing conditions. transplanting tomato seedlings has proved beneficial where soil pH is slightly acid to neutral. A package of control measures has been developed for control of the bacterium on potato, incorporating rotations with maize, weed control using herbicides, and soil amendments using urea and CaO. Varietal control is a possibility for tomato and eggplant, with selections having been made in Australia (Scorpio, Redlands, Summertaste, Redlander), Fiji (Alton) and Western Samoa. Resistance often breaks down under conditions of high temperatures and rainfall. The Peruvian potato varieties Caxamarca and Molinera are tolerant. Use of certified potato 'seed' is important in disease control strategies. In nurseries, use soil-Iess mixes or pasteurised soil. For chemical control: methyl bromide in greenhouse situations; disinfect tools with formaldehyde, methylated spirits or sodium hypochlorite after use on infected crops. T114 - PSEUDOMONAS SPP. - Lactuca sativa The bacteria are soilborne and survive in crop residues. Soft rots are favoured by hot, wet weather. In the field the bacteria are spread between plants in water droplets. Cultural control measures are important. Remove plants as soon as symptoms develop; avoid harvesting when plants are wet; disinfect knives used for cutting plants; after harvest remove crop residues or dig them in deeply; and practise crop rotation. If crops are irrigated, use furrow or trickle irrigation rather than overhead applications. T116 - PSEUDOPERONOSPORA CUBENSIS - Cucumis sativus The disease is windborne, and crops at different stages of growth should not be placed next to each other. To minimise the time that leaves are wet from dew or rain, crops should not be grown too densely. Overhead irrigation should be avoided. Varietal resistance exists in melon and watermelon (e.g. Chilton, Gulfcoast, Gulfstream, Planters Jumbo and Rio Gold), and cucumbers (Green Gem and Hybrid Sprint are resistant, as are Ashley, Cherokee, Burpless and Pixie-but the last four are susceptible to Sphaerothecafuliginea). For chemical control: benalaxyl plus mancozeb, chlorothalonil plus fenarimol, copper hydroxide, copper oxychloride, mancozeb, mancozeb plus metalaxyl, or propineb plus metalaxyl. TU5 - PSEUDOMONAS SOLANACEARUM - Capsicum annuum, Lycopersicon esculentum Control is difficult as the bacterium has a wide host range (sorne weeds may even be infected without showing symptoms), and it can survive in the soil for several years, making crop rotation of limited value. The bacterium can also be seedborne (sweet pepper and soybean). Amending the soil with urea (200 kg N/ha) and CaO (5 tlha) 3 weeks before T117 - PUCCINIA ARACRIDIS - Arachis hypogaea Varieties differ in their resistance to the rust. Seedborne infections are important and can be controlled by thiram. For chemical control in the field: bitertanol, chlorothalonil, cyproconazole, mancozeb or propiconazole. 171 TU8 - PUCCINIA THALIAE - Canna indica; PUCCINIA PAULLULA - Monstera deliciosa; PUCCINIA PELARGONllZONALIS - Pelargonium zonale For chemical control: bitertanol, chlorothalonil, copper oxychloride, copper oxychloride plus zineb, oxycarboxin or thiram. TU9 - PUCCINIA SORGHI- Zea mays Destroy volunteer plants before sowing. Varietal resistance exists (e.g. Suwan 1), but there are many races of the pathogen. Sorne super-sweet corn varieties are very susceptible. For chemical control: copper plus zineb, maneb or mancozeb. T120 - PYTHIUM SPP. - Colocasia esculenta Cultural control measures are important, including: (a) the removal of soil, roots and outer leaves from planting material taken from infected fields; (b) ensuring land is not liable to flooding or poorly drained and, for wetland taro, plants are not grown in stagnant water; (c) the removal of diseased plants immediately symptoms appear; and (d) the use of a fallow period or, if this is not practical, planting alternative crops. The use of fertilizers to promote vigorous plant growth can lessen the impact of disease. Varietal tolerance has been reported in several Pacific Island countries and pathogen-tested plants can be obtained from regional tissue culture laboratories. For chemical control: captan, metalaxyl or potassium phosphate as pre-plant dips on planting setts. The use of these chemicals in field plantings may be beneficial, but their effect is unproven. See SPC Plant Protection Leaflet No. 20 for further details on this pathogen and its control. 172 T121- PYTHIUM SPP. - Cucumis sativus Cultural control measures include: (a) thorough preparation of land to assist the decomposition of plant remains; (b) careful site selection to avoid poorly drained soil; (c) adjusting sowing density to avoid overcrowding; (d) preventing overwatering of seedlings; and (e) avoiding fruit coming into direct contact with soil with e.g. plastic mulches. Fruit grown commercially should be dry when packed and stored under cool, well-ventilated conditions. For chemical control: thiram for seed treatment to prevent damping-off. T122 - PYRENOPHORA GRAMINEA - Hordeum vulgare Resistant varieties are available. Seed treatment is important and fuberidazole plus triadimenol plus imazalil, or guazatine plus imazalil can be used. T123 - RADOPHOLUS SIMILIS - Cyrtosperma chamissonis, Musa sp., Zingiber officinale Cultural control measures are important. For ginger, rotate with crops of Colocasia taro, or cassava, or fallow the land. Avoid land previously planted to banana. Planting material should be carefully inspected and any with signs of rot rejected. Trim the planting material of the other two crops to ensure that the corm tissues are free from rots (giant swamp taro), or black or discoloured spots (banana). For banana, other techniques have been developed: the trimmed suckers are dipped in hot water (53°-54°C for 20-25 min) and planted in land that has been fallowed for at least 2 years, or planted with cover crops, such as green panic, Panicum maximum var. trichoglume, or a mixture of this grass and siratro, Macroptilium atropurpureum. For hot-water treatment of ginger use 48°C for 20 min or 51°C for 10 min. For chemical control: carbofuran, ethroprophos, fenamiphos or oxamyl. See SPC Plant Protection Leaflet No. 5 for further details on this pathogen and its control. T124 - RHIZOPUS STOLONIFERA - Fragaria x ananassa Overripe fruit should be removed at every harvest. Careful handling of the fruit after harvest and strict hygiene in the packing shed will also help to control the pathogen. Fruit should be cooled as soon as possible after harvest. For chemical control: benomyl or chlorothalonil. Treatments for powdery mildew are likely to be effective against this transit rot pathogen. Tl2S - SCLEROTINIA SP. - Vanda sp. For chemical control: benomyl, iprodione or vinclozolin. T126 - SCLEROTINIA MINOR - Lupinus albus, L. angustifolius Cultural control measures are important: destroy the remains of previous harvests or bury them deeply in the soil and rotate with resistant crops (cereals, onion and sweet potato). Avoid excessive applications of nitrogenous fertilizers. For chemical control: benomyl, iprodione, thiram or vinclozolin as foliar sprays and quintozene as a pre-plant soil treatment. T127 - SCLEROTINIA SCLEROTIORUM - Glycine max, Lactuca sativa; SCLEROTINIA FUCKELIANA - Helianthus annuus Cultural control measures are important: destroy crop remains of previous harvests or bury them deeply in the soil, rotate with resistant crops (cereals, onion and sweet potato), use low plant densities, and apply recommended fertilizers to ensure vigorous plant growth. Varietal resistance exists in sunflower, and the soybean varieties Ace, Corsoy, Hodgson and Maple Arrow. Soybean varieties Maple Presto and McCall also have useful tolerance. For chemical control: thiram as a seed treatment; and benomyl, iprodione, thiabendazole or vinclozolin as foliar sprays; and quintozene as a pre-plant soil treatment. T128 - SETOSPHAERIA TURCICA - Zea mays Cultural control measures include the destruction of volunteer plants and crop residues before sowing, and crop rotation. Differences exist between varieties in their tolerance to infection. For chemical control: thiram as a seed treatment. T129 - SOOTY MOULD FUNGI - Plumeria spp. For chemical control of insects: acephate, carbaryl, demeton-S-methyl, dimethoate, malathion, or malathion plus white oil. T130 - SPHAEROTHECA FULIGINEA - Carica papaya, Cucumis sativus A wide range of weeds and crops are hosts, so inoculum is available throughout the year. Vigorous crop growth should be encouraged through the use of appropriate fertilisers. Tolerant varieties of cucumber (Green Gem and Hybrid Sprint), melon (Chilton, Gulfcoast, Gulfstream, Planters Jumbo and Rio Gold) and watermelon are available, but the resistance may not be durable as it is controlled by a dominant gene. For chemical control: benomyl, carbendazim, dimethirimol, sulphur, triadimefon or triadimenol. Sulphur can burn the leaves, and resistance to the systemic products may develop. T131- SPHAEROTHECA MACULARIS - Fragaria x ananassa The fungus survives on diseased ratoon crops, and these should be removed between seasons. AIso, avoid overlapping crops. High humidity favours infection, while dry conditions encourage growth and sporulation of the fungus. For chemical control: benomyl or triadimefon, but strains resistant to these fungicides have been reported. Sulphur or dinocap can be used as alternatives. T132 - STIGMINA MANGIFERAE - Mangifera indica Rain or heavy dew favour outbreaks. Control measures recommended for anthracnose are likely to be effective. For chemical control: benomyl, copper oxychloride, mancozeb, or prochloraz plus mancozeb. 173 Tl33 - SUGARCANE FIJI OISEASE FIJIVIRUS - Saccharum edule Major epidemics of this disease in sugarcane have occurred in Australia and Fiji. They have only been brought under control by the selection of disease-free planting material, regular roguing of infected plants, and the use of resistant varieties. Heavily infected crops may be ploughed out. S. edule is susceptible. For chemical control of leafhopper vectors, Perkinsiella spp., if economically acceptable, dimethoate, endosulfan or malathion. Tl34 - SUN SCALD - Lycopersicon esculentum The disorder is due to fruits receiving excessive and damaging amounts of sunlight due to defoliation by, e.g. leaf pathogens. If they are controlled, the disorder will be prevented. Tl35 - THANATEPHORUS CUCUMERIS - Brassica oleracea var. capitata, Lycopersicon esculentum, Solanum tuberosum Cultural control measures are important, including the elimination of plant remains after harvest, good drainage, avoiding plant injury, and ensuring optimum plant nutrition. To prevent pre- and post-emergence damping-off use soil-less potting mixtures or pasteurised soil. Contact between fruit and the soil should be avoided by using plastic mulches or by staking (tomato and beans). For chemical control: benomyl or thiram as a seed treatment; quintozene as a pre-plant soil treatment; soil fumigation with methyl bromide or metam-sodium (tomato); formaldehyde, phenyl mercury acetate, sodium hypochlorite or quintozene as dips of 'seed' pieces (potato and yam). 174 Tl36 - TIPBURN - Lactuca sativa This physiological disorder is favoured by high diurnal temperatures causing excessive water loss. No cropping technique has given control, although fertilizer rich in phosphorus with moderate amounts of nitrogen and potassium may be beneficial. In greenhouses, it is important to be able to manipulate ventilation and shade in order to control temperatures. Tl37 - TRANZSCHELIA DISCOLOR - Prunus persica For chemical control: chlorothalonil, copper oxychloride, mancozeb, thiram, or zineb plus oil. Tl38 - UNKNOWN - Carica papaya Within the region served by the SPC, the disease has only been reported from New Caledonia, where it causes severe damage. Symptoms are similar to those of dieback in Australia which is thought to be caused by a phytoplasma (mycoplasma-like organism). No control measures are known. Trees may recover if they are eut back below the dead area. Tl39 - UREDO MUSAE - Musa sp. This is not an important pathogen and specifie control measures are unnecessary. The fungicides used against yellow or black Sigatoka diseases will control leaf rust, although sprays of oil alone, or extended spraying with benomyl, may encourage the occurrence of the pathogen. T140 - UREDO SP. - Chrysanthemum leucanthemum For chemical control: bitertanol, chlorothalonil, copper oxychloride, copper oxychloride plus zineb, oxycarboxin or thiram. T141- UROMYCES APPENDICULATUS var. APPENDICULATUSPhaseolus vulgaris Remove or bury plant remains deeply after harvest and use rotations of more than two years between bean crops. Intercropping beans with maize significantly reduces the incidence of infection. Varietal differences exist. For chemical control: bitertanol, copper hydroxide, mancozeb, metiram, oxycarboxin or zineb. T142 - UROMYCES STRIATUS - Medicago sativa Frequent cutting or grazing reduces the impact of the pathogen. Two strains exist and mixtures of luceme varieties are available with resistance. T143 - UROMYCES VIGNAE - Vigna unguicuIata ssp. sesquipedalis Destroy crop remains after harvest. For chemical control: carboxin or thiram as a seed treatment, and bitertanol, copper hydroxide, mancozeb, metiram or oxycarboxin as foliar sprays. T144 - UROMYCLADIUM TEPPERIANUM - Acacia spirorbis No treatment known. T145 - USTILAGO TRITICI - Triticum aestivum Varietal differences exist. For chemical control: carboxin plus imazalil plus thiabendazole. T146 - USTILAGO ZEAE - Zea mays Crop rotation is important as the pathogen is soilborne. It is also seedborne and seed should be treated with TCMTB, or thiram plus carboxin. In home gardens, remove and bum the infected plants before the galls rupture. Maintain well-balanced soil fertility and avoid mechanical damage to the plants during cultivation. Varietal differences exist, with most hybrids having a reasonable degree of resistance. T147 - VANILLA MOSAIC POTYVIRUS - Vanilla fragrans, Vanilla tahitensis Cultural control measures are important, including the use of propagating material from plantings free from symptoms of the disease, removal of infected plants immediately symptoms appear, disinfection of pruning knives with formaldehyde, methylated spirits or sodium hypochlorite, and washing hands with soap after working on plants that are diseased. Maintain weed control in plantations to reduce aphid populations which might otherwise spread the virus. T148 - VANILLA NECROSIS POTYVIRUS - Vanilla fragrans Control measures are identical to those for vanilla mosaic virus. T149 - VERTICILLIUM THEOBROMAE - Musa sp. Usually of minor importance and control measures are not warranted. Hand removal of the floral remains about 10 days after bunch emergence is practised in sorne countries. For chemical control: copper fungicides either sprayed or dusted over the fruit, or thiabendazole as a post-harvest dip. T150 - XANTHOMONAS CAMPESTRIS pv. CAMPESTRISRaphanus sativus An important disease of quarantine concem in those countries yet free from the bacterium. Cultural measures are important in the control of the pathogen, including ensuring seedlings are not overcrowded, the removal of susceptible weeds, the removal or deep burial of crop remains immediately after harvest, and crop rotation. If crops are irrigated, it is best to avoid overhead systems. Seedborne infections are important and can be controlled by treating the seed in host water (45°C for 25-30 min 175 or 50°C for 15-25 min). The cabbage varieties Beauty, Hi-Yield and Hybrid 33 have sorne resistance to infection. For chemical control: copper hydroxide, beginning on seedlings in the nursery, especially if seed treatment has not been applied. T151- XANTHOMONAS CAMPESTRIS pv. CITRI - Citrus spp. An important disease of quarantine concern to those countries yet free from the bacterium. Eradication attempts have been successful in sorne countries. Once established the pathogen is difficult to control. Cultural methods of control are important, including pruning of branch cankers and planting windbreaks around orchards to prevent the pathogen spreading in wind-driven rain, as weIl as reducing physical damage which might assist entry of the bacterium. Lemons, mandarins and seedless limes are more resistant than grapefruit and oranges. For chemical control: copper fungicides. T152 - XANTHOMONAS CAMPESTRIS pv. MANGIFERAEINDICAE - Mangifera indica An important disease of quarantine concern to those countries yet free from the bacterium. Cultural control measures are important. It is essential that seedlings and grafted plants are free from infection. Do not establish nurseries near mango plantings and select scion wood from disease-free trees. Treat propagating material with copper fungicides. Establish new plantings in areas protected fram strong winds and provide windhreaks around and within the orchard. Varietal differences exist. In Australia varieties Carabao, Early Gold, Kensington, Nam Dok Mai and Sensation have resistance. For chemical control: copper oxychloride (except during flowering). 176 T153 - XANTHOMONAS CAMPESTRIS pv. MANIHOTIS - Manihot esculenta An important disease of quarantine concern to those countries yet free from the bacterium. Cultural control measures include the destruction of plant remains after harvest, the selection of cuttings for propagation from disease-free plants, crop rotation and avoiding planting crops of different ages adjacent to each other. Varieties differ in their tolerance to the bacterium, and sorne with resistance, bred at international agricultural research centres, are available as pathogen-tested plantlets from regional tissue culture laboratories. T154 - XANTHOMONAS CAMPESTRIS pv. VESICATORIA Lycopersicon esculentum An important disease of quarantine concern to those countries yet free from the bacterium. Cultural control measures include the destruction of plant remains after harvest, crop rotation (at least 2 years), and the removal of alternative hosts, weeds included. Varietal differences exist in sweet pepper. Seedborne infections are important and can be controlled in tomato by treating seed in hot water (50°C for 25 min.) For sweet pepper, seed should be obtained certified free of the pathogen. For chemical control in field crops: chlorothalonil, copper hydroxide, copper oxide, copper oxychloride, or copper oxychloride plus zineb. T155 - ZUCCHINI YELLOW MOSAIC POTY VIRUS - Cucurbita pepo The virus is spread by aphids, and sorne crucifers act as reservoirs of infection. Cultural control measures include the roguing of alternative hosts and the destruction of residues as soon as the crop has been harvested. Overlapping crops should be avoided, particularly when growing zucchini. Reflective mulches have been used with sorne success when combined with applications of insecticide, such as demeton-Smethyl, endosulfan or malathion, to kill the aphids. Insecticides alone have litde effect. 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The fungi, bacteria and pathogenic algae of Solomon Islands. Suva, Fiji: FAO, RAS/83/001; Strengthening Plant Protection and Root Crops Development in the South Pacifie, Field Document Il. 179 McKenzie, E.R.C. (1989). The fungi, bacteria and pathogenic algae of Vanuatu. Suva, Fiji: Forum Secretariat. Persley, D., ed. (1993). Diseases of Fruit Crops. Department of Primary Industries, G.P.O. Box 46, Brisbane, Q 4001, Australia. McKenzie, E.R.C. (1996). Fungi, bacteria and pathogenic algae on plants in American Samoa. Noumea, New Caledonia: South Pacifie Commission; Technical Paper 206. Persley, D., ed. (1994). Diseases of Vegetable Crops .. Department of Primary Industries, G.P.O. Box 46, Brisbane, Q 400 l, Australia. McKenzie, E.R.C., Jackson, G.Y.R. (1990). The fungi, bacteria and pathogenic algae ofthe Republic ofPalau. Noumea, New Caledonia: South Pacifie Commission; Technical Paper 198. Peskem-Australian Directory ofRegistered Pesticides and tlzeir Uses. The University of Queensland, Gatton College, Lawes, Q 4343, Australia. Plant Protection Advisory Leaflets. Noumea, New Caledonia: South Pacifie Commission. McKenzie, E.R.C., Jackson, G.Y.R. (1990). The fungi, bacteria and pathogenic algae of the Federated States of Micronesia. Noumea, New Caledonia: South Pacifie Commission; Technical Paper 199. Regional Agro-Pesticide Index Asia and the Pacifie. Bangkok, Thailand: ARSAP/CIRAD. (Available through South Pacifie Commission). McKenzie, E.R.C., Jackson, G.Y.R. (1996). Fungi and bacteria on plants in the Marshall Islands. Noumea, New Caledonia: South Pacifie Commission; Technieal Paper 207. Russo, Y., Beaver, G., Cruz, F., Rubin, H. (1985). Plant pathogens and associated hosts on Guam. University of Guam, Technical Report, AES Publication No. 46. Mossop, D.W., Fry, P.R. (1984). Records ofviruses pathogenic on plants in Cook Islands, Fiji, Kiribati, Niue, Tonga and Western Samoa. Rome, Italy: UNDPIFAO-SPEC Survey of Agricultural Pests and Diseases in the South Pacifie, Technical Report Volume 7. Shaw, D.E. (1984). Microorganisms in Papua New Guinea. Port Moresby, Papua New Guinea: Department of Primary Industry, Research Bulletin No. 33. New Zealand Agrochemical Manual. P.O. Box 11092, Wellington, New Zealand. Orton Williams, K.J. (1980). Plant parasitic nematodes ofthe Pacifie. St. Albans, UK: Commonwealth Relminthology; UNDP/FAO-SPEC Survey of Agricultural Pests and Diseases in the South Pacifie, Technical Report Volume 7. 180 The Pesticide Manual (Incorporating the Agrochemicals Handh()()k). British Crop Protection Council, Bear Farm, Binfield, Bracknell, Berkshire, RG42 5QE, UK. The UK Pesticide Guide. CAB International and the British Crop Protection Council. CAB! Centre, Wallingford, OXON, OXIO 8DE, UK. Index hosts A Abelmoschus esculentus 4, 170 Acacia spirorbis 4, 175 Acidovorax avenae subsp. citrulli 32. 155 Actinidia deliciosa 4, 163 Aecidiumfragiforme 6, 155 Agathis spp. 6, 155, 163 Albugo candida 18, 126, 155 A. ipomoeae-aquaticae 76, 155 Allium cepa 6, 159 A. porrum 8, 156 A. sativum 8, 156 Alocasia macrorrhizos 8, 52, 56, 166 Altemaria altemata 112, 155 A. brassicae 18 A. brassicicola 18, 155 A. dauci 64, 155 A. passiflorae 112-114, 155 A. porri 8, 156 A. radicina 66, 155 A. solani 86, 130, 155 Ananas comosus 10, 158 Annona squamosa 10, 163 Anthurium 10, 12 Anthurium andreanum 162-163 pathogens Apium graveolens 12, 157, 163 Apple 92, 164 Arachis hypogaea 14, 156, 166, 171 Aranda 16 Aranda sp. 16, 163 Arrowroot 134 Artocarpus altilis 16-18, 164, 169 Ascochyta cucumis 30, 60 Aspergillus flavus 36, 156 A. niger 8, 156 Athelia rolfsii 14, 66, 86, 156 Avocado 116, 144, 163-164 B Balanophorafungosa 74, 156 Banana(s) 10, 16, 100-110, 157-158, 160,162, 164, 166, 172 Banana bunchy top nanavirus 108, 156 Banana streak badnavirus 108, 157 Barley 76 Batiki blue grass 80 Bean(s) 14, 74, 161, 166, 174-175 Bele 4, 108 Betel nut 40, 42 Bipolaris incunJata 38, 157 B. maydis 146 Bitter melon 100 Black pepper 18, 34, 116 Blackeye cowpea mosaic potyvirus 144, 157 Blossom-end rot See Physiological disorder Botryodiplodia theobromae 16 Brassica chinensis 18, 155 B. oleracea var. capitata 18-20, 155, 161, 168, 174 Breadfruit 16, 18, 116, 169 Bremia lactucae 80, 157 Broccoli 20 Brown heart See Physiological disorder Bush lemon 32 c Cabbage(s) 18-20, 74, 126,155-156 161, 176 Cadang-cadang viroid 44, 159 Cadang-cadang-like viroid 70, 157 Caladium 58 Canna 22 Canna indica 22, 172 Capnodiu1ll citri 34, 166 Capsicum annuum 22-24, 158-159, 162, 171 181 Caribbean pine 120 Carica papaya 24-28, 160, 163, 167, 170, 173-174 Carrot 64-66, 74, 155 Cassava 96-98, 166, 172 Cassava green mottle nepovirus 98, 158 Cassytha filiformis 120, 158 Casuarina equisetifolia 28, 163 Cattleya 16 Cauliflower 20, 126 Celery 12, 20, 74 Centro 114 Cephaleuros minimus 116 C. parasiticus 116 C. virescens 116, 158 Ceratocystis paradoxa 10, 128, 158 Cercospora capsici 22, 158 C. carotae 64 C. coffeicola 44, 158 C. colocasiae 8 C. ipomoeae 76, 158 C. longissima 80, 158 C. mangiferae 94 C. taccae 134, 158 Cercosporidium henningsii 96 C. personatulll 14 Cereals 173 Cerebella andropogonis 110, 158 Chalara paradoxa 10, 128 Chili 22, 88 Chinese cabbage 18-20, 126, 155 Chrysanthemum 30 Chrysanthemum leucanthemum 30, 174 Citrullus lanatus 30-32, 155, 159, 161 Citrus 32-36, 48, 116, 122, 136, 170 Citrus spp. 32-36, 163, 166, 168, 170, 176 Citrus tristeza closterovirus 170 Cladosporium colocasiae 50, 158 182 C.fulvum 86 Claviceps spp. 110 Cochliobolus heterostrophus 146, 158 Cocoa 16, 48, 116, 134-136, 164, 167,169 Coconut(s) 8-10, 36-44, 158-160, 165, 168, 170 Coconut foliar decay virus 44, 159 Coconut tinangaja viroid 44, 159 Cocos nucifera 36-44, 156-157, 159-160, 165, 168-169, 171 Coffea arabica 44-50, 158, 162-164, 168 C. canephora 44-50, 158,162-164, 168 Coffee 16, 44-50 Coleosporium plumeriae 122, 159 Colletotrichum capsici 22, 159 C. circinans 6, 159 C. falcatum 130 C. gloeosporioides 4-6, 10-12, 16, 26, 32, 46, 66, 92, 96,112, 116-118, 124, 138-140 C. lagenarium 30, 60 C. lindemuthianum 84, 159 C. orbiculare 30, 60, 159 Colletotrichum sp. 100, 159 Colocasia bobone disease (?) rhabdovirus 56, 159, 160 Colocasia bobone disease (?) rhabdovirus (Fiji stram) 56, 160 Colocasia esculenta 50-58, 158-61, 164, 165, 167, 169, 171, 172 Copra 156 Cordana musae 100, 104, 160 Cordia alliodora 58, 169 Corn See Maize Corticium koleroga 48 C. penicillatum 38, 160 C. salmonicolor 34, 48, 136 Corynespora cassiicola 24, 60, 160 Cotton 165 Cowpea 84, 144, 166 Crucifers 18-20, 126, 176 Cucumber(s) 20, 60-62,159-161, 171, 173 Cucumber mosaic cucumovirus 108-110, 120, 160 Cucumis melo 60, 159 C. sativus 60-62,160-161, 171-173 Cucurbita pepo 64, 176 Cucurbits 14, 28-30, 60-64, 110, 120, 144, 155, 161 Curvularia ischaemi 80, 161 Cynodon dactylon 40 Cyrtosperma chamissonis 64, 172 D Dallis grass See Paspalum Dasheen bacilliform (?) badnavirus 56, 160 Dasheen mosaic potyvirus 58, 146, 161 Dasheen mosaic potyvirus (severe strain) 58, 161 Datura spp. 170 Daucus carota 64-66, 155-156 Deightoniellapapuana 128, 161 D. torulosa 100 Didymella bryoniae 30, 60, 161 Dietlenbachia 58 Dioscorea spp. 68-70, 163-164, 170 Dioscorea alata 66, 163 Diplodia natalensis 116 Drechslera graminea 76 D. incurvata 38 Duruka 126 E G Echinochloa colona 40 Eggplant 4, 22-24, 88, 165, 171 Elaeis guineensis 70, 157 Eleusine indica 40 Elsinoe batatas 78, 161 E.fawcettii 32, 161 E. sacchari 128, 161 Ganoderma applanatum 28, 163 Garlic 8 Geranium 114 Gerbera 72 Gerbera sp. 72, 163 Giant swamp taro 58, 64, 108, 146, 164, 172, Giant taro 8, 52, 56, 58, 146 Gibberellafujikoroi 146, 163 Ginger 108, 150, 166, 172 Gladiolus 72 Gladiolus sp. 72, 162 Glomerella cingulata 4-6, 10-12, 16, 26, 32, 46, 66, 92, 96, 112, 116-118, 124, 138-140, 163 G. tucumanensis 130, 163 Glycine max 74, 173 Goplana australis 68, 163 G. dioscoreae 68, 164 Granadilla 114 Grapefruit 176 Grass(es) 20, 40, 110, 130, 146, 150, 161, 165, 172 Greater yam 66 Green panic 166, 172 Guava 116, 122, 124 Guignardia musae 102, 164 G. dioscoreae 68, 164 Erwinia carotovora 106 E. carotovora pv. atroseptica 132 E. carotovora pv. carotovora 132 E. chrysanthemi 106, 132 Erwinia spp. 20, 54, 132, 161 Erysiphe spp. 94, 144 Exserohilum turcicum 148 F Forest trees 16, 34 Fragaria x ananassa 70-72, 173 Frangipani 122 French bean(s) 84, 118, 144, 159 Fulviafulva 86, 162 Fusarium moniliforme 146 F. oxysporum 12, 24, 122, 140-142, 162 F. oxysporum f. sp. coffeae 46, 162 F. oxysporum f. sp. cubense 102, 162 F. oxysporum f. sp. gerberae 72, 163 F. oxysporum f. sp. gladioli 72, 162 F. oxysporum f. sp. vanillae 140, 162 Fusarium spp. 132 H Helianthus annuus 74,173 Hemileia vastatrix 46, 164 Hibiscus rosa-sinensis 74, 156 H. tiliaceus 159 Hirschmanniella miticausa 54, 164 Hordeum vulgare 76, 172 1 InternaI browning See Physiological disorder Ipomoea aquatica 76, 155 1. batatas 78, 161, 170, 171 /sariopsis griseola 118 Ischaemum indicum 80, 161 Itchgrass See Rottboellia K Kangkong 76 Kauri 6 Kava 120, 160 Kiwi fruit 4 L Ltu:tucasativa 80-84, 157-158, 164, 171, 173-174 Lasiodiplodia theobromae 16, 116, 164 Laurel 58 Leucaena 16 Leek 8 Legume(s) 20, 26, 38, 62, 84, 92, 108, 110, 120 144, 169 Lemons 176 Lettuce 80-84, 164 Lettuce mosaic potyvirus 84, 164 183 Leucaena sp. 136 Leveillula taurica 88, 164 Limes 176 Little-leaf 78 Low temperature breakdown See Physiological disorder Lucerne 98, 165, 175 Lupin 84 Lupinus albus 84, 159, 173 L. angustifolius 84, 159, 173 Lycopersil:on esculentum 86-92, 155-157, 162, 164, 170-171, 174, 176 M Macroptilium atropurpureum 120, 166, 172 Magnaporthe salvinii 110, 165 Maize 8, 36, 40, 64, 130, 146-150, 156, 168, 171 175 Maize mosaic rhabdovirus 150, 165 Malus x domestica 92, 164 Mandarin(s) 32, 176 Mangifera indica 92-94, 163, 167, 173, 176 Mango(es) 16,92-94, 116, 122,163, 167,176 Manihotesculenta 96-98, 158, 163, 166, 168, 176 Marasmiellus albofilscus 38, 165 M. cocophilus 40, 165 M. inoderma 40, 102, 165 M. stenoph.vllus 50, 165 Medicago sativa 98, 175 Meloidogyne spp. 120, 165 Melon 30, 60, 62, 171, 173 Momordica charantia 100, 159 Monstera deliciosa 100, 172 Morning glory 78 Musa sp. 100-110, 156, 160, 162-166, 169, 172, 174-175 184 Mycoplasma-like organism 78, 92, 132, 174 Mycosphaerella alocasiae 8, 166 M. arachidis 14 M. berkeleyi 14, 166 M. fijiensis 104, 166 M. henningsii 96, 166 M. musicola 104, 166 N Nakataea sigmoidea 110 Neojohnstonia colocasiae 52, 167 o Oidiopsis taurica 88 Oidium sp. 26, 62, 72, 94, 144, 167 Oil palm 16, 40-42, 70 Okra 4 Oncobasidium theobromae 134, 167 Onion(s) 8, 156, 159, 161, 173 Orangees) 170, 176 Oryza saliva 110, 165 Oxalis spp. 148 p Palms 157 Panicum maximum var. trichoglume 166, 172 Papaya 16-18, 24-28, 144, 160, 163-164, 169 Papaya rings pot potyvirus 28, 167 Paracercospora fijiensis 104 Pseudocercospera musae 104 Paspalum 110 Paspalum dilatatum 110, 158 Passiflora edulis 112-114, 155, 163, 167 P. edulis x P. edulis f.flavicarpa 167 P. foetida 114 P. quadrangularis 114, 155 Passionfruit 16, 112-114, 164 Passionfruit woodyness potyvirus 114, 167 Peach 122-124 Peanut(s) 8,14, 24, 114, 156, 166 Pelargonium zonale 114, 172 Pellicularia koleroga 48, 168 Penicillium digitatum 34, 168 P italicum 34, 168 Periconia manihoticola 96, 168 Peronosclerospora sacchari 148, 168 Peronospora parasitica 20, 168 Persea americana 116, 158, 163-164 Pestalotiopsis disseminata 124, 168 P palmarum 40, 168 Phanerochaete salmonicolor 34, 48, 136, 168 Phaseoisariopsis griseola 118, 168 Phaseolus vulgaris 118-120, 163, 165, 168, 175 Phellinus lamaensis 48, 168 P noxius 16, 58,169 Philodendron 58 Phoma spp. 52, 169 Phyllachora musicola 100, 169 Phyllosticta dioscoreae 68 P musarl/m 102 Phyllosticta sp. 52 Physalis spp. 170 Physiological disorder Blossom-end rot 90, 157 Brown heart 92, 157 InternaI browning 92, 164 Low temperature breakdown 92 Sun scald 90, 174 Tipburn 82, 174 Phytophthora caps ici 142 P colocasiae 52, 169 P heveae 42, 169 Pllicotianaevar.parasitica 26,36, 138, 142, 170 P palmivora 18, 26, 42, 136, 140-142, 169 P parasitica. See P Ilicotianae var. parasitica Phytoplasma 78, 92, 132, 170 Pineapple 10, 158 Pinus caribaea 120, 158 Piper methysticum 120, 160 Plantain(s) 160, 166, 167 Plumeria spp. 122, 159, 173 Polynesian ironwood 28 Poncirus trifoliata 170 Potato(es) 74, 86, 110, 130-132, 156, 161-162, 166, 171, 174 Potato leafrolliuteovirus 132, 170 Pratylenchus coffeae 70, 170 Prunuspersica 122-124, 162, 174 Pseudocercospora abebnoschi 4, 170 P colocasiae 54, 171 P timorellsis 78, 171 Pseudoepicoccum cocos 42, 171 Pseudomonas solanacearwll 24, 88, 162, 171 P pseudoalcaligenes See Acidovorax m'enae subsp. citrulli Pseudomonas spp. 82, 171 Pseudoperonospora cubensis 62, 171 Psidium guajava 124, 163, 168 Puccinia arachidis 14, 171 P canllae 22 P paullula 100, 172 P pelargonii-zonalis 114, 172 P polysora 148 P sorghi 148, 172 P thaliae 22, 172 Pumpkin 62, 64 Purple passionfruit 155, 167 Pyrenophora graminea 76, 172 Pythiul1l aphanidenllatum 62 P splelldells 54 Pythium spp. 54, 62, 172 R Radish 126, 155 Radopholus similis 108, 150, 172 Raphanus sativus 126, 155, 175 Rhizoctonia solani 20, 88, 130, 140 Rhizopus stolonifera 70, 173 Rice 40, 110 Rottboellia 150 Rough lemon 161 Rubber 34 s Saccharum edule 126, 174 S. officinarum 128-130, 158, 161, 163 Sclerospora sacchari 148 Sclerotinia fuckeliana 74, 173 S. minor 84, 173 S. sclerotiorum 74, 82, 173 Sclerotiniasp. 140,173 Sclerotium rolfsii 14, 66, 86 Sea bean 144 Setaria 150 Setosphaeria turcica 148, 173 Shallot 8 She oak 28 Siratro 114, 166, 172 Solanumtuberosum 130-132, 155, 161, 170, 174 Sooty mou1d fungi 122, 173 Sorghum 130, 146, 148, 150 Sour orange 32 Soursop 116 Soybean 74, 84, 114, 144, 171, 173 Sphacelollla fawcettii 32 S. sacchari 128 Sphaerotheca fuliginea 26, 62, 171, 173 S. macularis 72, 173 Split leaf Philodendron 100 Squash 62, 64 Stemphylium radicinum 66 Stigmina mangiferae 94, 173 Strawberry 70-72 Sugar apple 10 Sugarcane 10, 126-130, 148, 157-158, 168 Sugarcane Fiji disease fijivirus 126, 174 Sun scald See Physiological disorder Sunflower 74, 173 Sweet corn 172 Sweetpepper(s) 22-24, 158-159, 165,171, 176 Sweet potato 14, 76-78, 88, 158, 166, 173 Sweetsop 10 Swietenia macrophylla 58 T Tacca leontopetaloides 134, 158 Tannia 146 Taro 14, 40, 50-58, 62, 146, 164-166, 169, 172 Taro palagi 146 Tea 34 Tectona grandis 58 Thanatephorus cucwlleris 20, 88, 174 Theobroma cacao 134-136, 167-169 Tipbum See Physiological disorder Tomato 4, 22, 74, 86-92, 110, 130, 132, 155, 161, 165-166, 171, 174,176 Trallzschelia discolor 124, 174 T pruni-spinosae 124 185 Trichoderma harzianum 156, 162 T. koningii. 162 T. viride 156 Trifoliate orange 32 Triticum aestivum 138, 175 u Unknown 28, 174 Uredo musae 106, 174 U. pseudocannae 22 Uredo sp. 30, 174 Uromyces appendiculatus var. appendiculatus 118, 175 U. phyllodiorum 4 U. striatus 98, 175 U. vignae 144, 175 Uromycladium tepperianum 4, 175 Ustilago maydis 150 U. tritici 138, 175 U. zeae 150, 175 v Vanda 13R, 140 Vanda sp. 138, 140, 163, 170, 173 Vanilla 140-142, 169 Vanilla fragrans 140-142, 162-163, 169, 175 V. tahitensis 142, 169, 175 Vanilla mosaic potyvirus 142, 175 Vanilla necrosis potyvirus 142, 175 Verticillium hemileiae 50 V. theobromae 106, 175 Vignaunguicu1aJassp.sesquipeda/is 144, 157, 167, 175 186 w Water Spinach 76-78 Watermelon 30-32, 62, 64, 171, 173 Wattle 4 Weeds 14,38, 110, 126, 171, 173, 175 Wheat 138 Wild passionfruit 114 Witches' broom disease 78 x Xanthomonas campestris pv. campestris 18, 126, 155, 175 X. campestris pv. citri 36, 176 X. campestris pv. mangiferaeindicae 94, 176 X. campestris pv. manihotis 98, 176 X. campestris pv. vesicatoria 90, 176 Xanthosoma sagittifolium 146, 161 y Yam(s) 20, 68-70, 108, 163, 166, 174 Yard-long bean 144 Yellow passionfruit 155, 166 z Zea mays 146-150, 158, 163, 165, 168, 172-173, 175 Zingiber officinale 150, 172 Zucchini 62, 64 Zucchini yellow mosaic potyvirus 64, 176

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