RMMCKC73–. Fn.. 114.—l-'oiiusfomcntarius. l-'ungus willi a portion cut out to show stratified pores, reduced. (^8, I OS. od.) was paid annually for the material obtained from Bischoffsrent forest in Bavaria. Ten years ago the same brought in a revenue of twelve shillings, to-day it is free, owing to our advance in knowledge as to the injurious elTect of fungus parasites, and the adoption of means for tlie pre- vention of the same. Unfortunately i)revcntive measures against this, as well as other of the larger wound-fungi, arc practically confined to protecting injured surfaces by means of gas-tar. Frui
RMRCD8NG–. Diseases of cultivated plants and trees. Plant diseases; Plants -- Wounds and injuries; Plants, Protection of; Trees -- Diseases and pests. 396 DISEASES OF CULTIVATED PLANTS Wholly resupinate, or most frequently reflexed, the free portion projecting from the matrix, often crisped and lobed, coarsely fibrous above, dingy ochraceous ; hymenium smooth, bright ochraceous; spores elliptical, hyaline. It is difficult to suggest preventive measures against a fungus present practically everywhere. When growing on a. I'lc. 121,. — Shrciini hirsiitiim. i, fungus; 2, section of saiiK' ; 3, basidia hi-n
RMMCTMJB–. Fig. 55.—Gnomonia erythrostoma. i, conceptacles containing spermatia bursting through the epidermis of a leaf; 2, spermatia ; 3, section of perithecium of ascospore stage ; 4, ascus containing spores ; 5, free spores. All mag. from one orchard to another. Frank records an instance in Prussia where the cherry industry was completely wrecked by this disease, but after two years' work in collecting and burn- ing all infected leaves, the epidemic was thoroughly stamped out, and a return to the former productiveness followed. Wild cherries growing in woods and the bird cherry {Friinus avium) are
RMRCD99X–. Diseases of cultivated plants and trees. Plant diseases; Plants -- Wounds and injuries; Plants, Protection of; Trees -- Diseases and pests. 158 DISEASES OF CULTIVATED PLANTS is somewhat erratic in its appearance, and during certain seasons it covers both surfaces of the leaves of gooseberries with a delicate greyish-white mildew. Less frequently the fruit is also attacked. When the mycelium is well established on the leaf, it becomes covered with a mass of conidia, giving to it a mealy appearance. The ascigerous condition is usually produced in abundance later in the. KiG. ^o.—Microsphaera ^
RMMCKC0K–. Fig lyj.—Plasmodiophora brassicae. i, young turnip showing early stage of disease ; 2, cabbage showing clubbed root; 3, two infected cells from root of cabbage, one con- taining plasniodium, tlie other crowded with minute spores of the parasite ; 4, three myxamoebae or motile bodies pro- duced by the spores on germination. Figs. 3 and 4 highly mag. It will be impossible to stamp out the disease unless proper precautions are taken. In the case of cabbages grown in
RMRCD8YR–. Diseases of cultivated plants and trees. Plant diseases; Plants -- Wounds and injuries; Plants, Protection of; Trees -- Diseases and pests. PUCCINIA 311 I as in other instances, one attack implies immunity in the j future. i ! Pink rust {Puccinia arenariae, Wint.) often causes injury j to cultivated pinks and carnations. It forms small blackish spots arranged in irregular circles on the leaves and stem. H', ; . .••.?. ... ..V -%^-. Fig. 91.—Puccinia malvacearum. Hollyhock leaf showing pustules of fungus ; 2, teleutospores, one germinating. Highly mag. Teleutospores only are present. These ar
RMMCMTCE–. Fig. 61.—Plowrightia mcrhosa. i, portion of a plum branch, showing conidial stage of the fungus; 2, branch with ascigerous condition of the fungus ; 3, conidiophores bearing conidia ; 4, ascus containing 8 spores. Figs, i and 2 rethiced ; rest highly mag. obvate, hyaline, i-septate, basal cell much the smaller of the two, 15-20 X 8-10 i. The only practical method of dealing with this disease is to cut out all diseased knots. When the tree is badly infected, new knots frequently develop at or near the points from which knots have been cut away. In such cases the
RMRCE2ED–. Diseases of cultivated plants and trees. Plant diseases; Plants -- Wounds and injuries; Plants, Protection of; Trees -- Diseases and pests. ;56 DISEASES OF CULTIVATED PLANTS rounded by a number of stunted and distorted shoots. Diseased plants are checked in growth and remain stunted. Eelworms and their eggs are usually present in considerable numbers in the swollen parts.. Deep ploughing and treating with sulphate of potash are recommended when the land has produced a diseased crop. As the eehvorm attacks many different kinds of plants, it is important to avoid growing a crop on land that is
RMMCW0BJ–.
RMRCE2G2–. Diseases of cultivated plants and trees. Plant diseases; Plants -- Wounds and injuries; Plants, Protection of; Trees -- Diseases and pests. MYXOGASTRES 533 Speedwell {Veroniia). The galls contain numerous spore- balls, each enclosed in a delicate membrane, and consisting of a single layer of elliptical spores enclosing a central cavity. The individual spores measure 8-9 X 4-4*5 1^- Tetramyxa parasitica (Goeb.) forms little swellings on stalks, leaves, and flowers of Riippia rostdlata. The multi- nucleate Plasmodium breaks up into small portions, each con- taining a nucleus. Iliese portions a
RMMCKC8P–. P'iG. 104. — Urocystis occulta. i, upper part of rye plant diseased ; 2, spores, one of w hich has germinated and produced a cluster of secondary spores at the apex of the germ-tube ; 3, a spore that has germinated and produced secondary spores, two of which have germinated. Figs 2 and 3 highly mag. also attacked. The fungus bursts through the epidermis as large, black, powdery streaks. Spore-clusters 18-25 i diam., usually only one, brown, central, fertile cell, surrounded by many pale, sterile cells. White varieties are most susceptible to the disease. Infec- tion occurs during seedling s
RMRCD99F–. Diseases of cultivated plants and trees. Plant diseases; Plants -- Wounds and injuries; Plants, Protection of; Trees -- Diseases and pests. MELIOLA 163 aphides should be kept in check. Resin wash is the best- known remedy for the sooty moulds. Often covering the entire surface of the leaf with a black, velvety felt; perithecia narrowly ovate, elongated, asci pear- shaped, 48-50 X 30 /^, S-spored ; spores hyaline, i-septate, elliptical, slightly constricted at the septum, 12-15x5-6 /*. MELIOLA (Fries.) Perithecia seated on black, radiating mycelium, globose, often furnished with specialised a
RMMCPG85–. 1*"k;. 54. — (rno»iofiia erythrostinna. Branch with persistent, drooping, dead leaves. the following season after the new leaves have appeared. The fruit is also attacked at times, when it becomes distorted and ripens unevenly. During the winter months the higher or ascigerous form of fruit is developed on the dead, hanging leaves. The s])ores produced by this form of the fungus infect the young leaves the following season. The perithecia of the conidial form are very minute, and burst through the epidermis of the leaf, ostiolum not elon- gated ; sporophores branched ; spores filiform,
RMRCD8R2–. Diseases of cultivated plants and trees. Plant diseases; Plants -- Wounds and injuries; Plants, Protection of; Trees -- Diseases and pests. MERULIUS 365 Dry Rot {Merulius lacrymatis, Fries.).—The cause of this mischief is almost unknown in a wild state, although as a destroyer of worked timber it occurs practically everywhere.. Fig. 2.-Menilii/s lacrymans. ' Dry-rot' ; you.ig specimen, nat. size. The specific name ' lacrymans,' or weeping, was given on account of the drops of water that frequently drip from the fungus, and which it has the power of absorbing from the atmosphere. This mois
RMMCKC7A–. Fig. 2.-Menilii/s lacrymans. ' Dry-rot' ; you.ig specimen, nat. size. The specific name ' lacrymans,' or weeping, was given on account of the drops of water that frequently drip from the fungus, and which it has the power of absorbing from the atmosphere. This moisture enables the fungus to attack
RMRCD8XH–. Diseases of cultivated plants and trees. Plant diseases; Plants -- Wounds and injuries; Plants, Protection of; Trees -- Diseases and pests. CRONARTIUM 319 CRONARTIUM (Fries.) Aecidia produced on conifer leaves (so far as known), peridia elongated, aecidiospores in chains. Uredospores pro- duced in a pseudoperidium, brown. Teleutospores i-celled,. Fig. 96.—Cronartium ribicohint. i, uredo and teleuto- spore stages on leaf of black currant; 2, uredospores, (Z, and teleutospores, b, cemented together in a column ; 3, uredospore ; 4, teleutospores, two of which are germi- nating ; 5, aecidia on b
RMMCMKWP–.
RMRCD944–. Diseases of cultivated plants and trees. Plant diseases; Plants -- Wounds and injuries; Plants, Protection of; Trees -- Diseases and pests. ROSELLIXIA ^37 external weft is formed it produces two types of sclerotia. The most general type consists of numerous minute blackish- violet sclerotia which resemble in size and general appearance the perithecia of some Sphaeria. If a section of the host- plant bearing such microsclerotia is examined, the sclerotium is seen to be more or less dumbbell-shaped, a short, thick neck penetrating the tissue of the host, consisting of closely. Fig. 68.—Swede,
RMMCTM6W–. Fig. 52.—Sphaerella fra^^ariae. i, a diseased straw- berry leaf; 2, ascus containing eight spores of the Sphaerella or ascigerous stage; 3, conidia of the Ratnularia or conidial stage. 1-igs. 2 and 3 liighly mag. irregular patches. By degrees the centre of the patch assumes an ashy-grey or almost white colour, and is bounded by a reddish border, which is often ([uitc bright in colour later in the season. The central portion then becoaies studded with very minute white tufts of the conidial form of fruit. Later in the season these minute white tufts are replaced by minute black points—the asc
RMRCD9DG–. Diseases of cultivated plants and trees. Plant diseases; Plants -- Wounds and injuries; Plants, Protection of; Trees -- Diseases and pests. SYNCHYTRIUM [03 is known to be infected, by having produced a diseased crop, do not attempt to grow a crop of potatoes again for at least six years, unless very stringent measures are taken to destroy the organisms present in the soil. The land must be fallowed and dressed with gas-lime, at the rate of from four to five tons per acre. SHghtly diseased potatoes should not be given to animals raw, but should be always boiled first. Journ. Bd. Agric, Leafle
RMMCKCCY–. I % Fig. 78.—Sclcroiiniii sileroliorum. i, part of a chrysanthemum stem with black scleiotia of the fungus ; 2, a sclerotium bearing five ascigerous fruits ; 3, ascus with spores. Figs. 2 and 3 mag. bers, melons, hemp, petunias, zinnias, and chrysanthemums being among the number of its victims. The disease com- monly attacks the stem, commencing as a white mould at the ground-line and working upwards. When the parasite has been at work for some time tiie leaves turn yellow and wilt, and finally the stem collapses, death being due to lack of food and water, owing to the mycelium of the fungus
RMRCD984–. Diseases of cultivated plants and trees. Plant diseases; Plants -- Wounds and injuries; Plants, Protection of; Trees -- Diseases and pests. â im.. Please note that these images are extracted from scanned page images that may have been digitally enhanced for readability - coloration and appearance of these illustrations may not perfectly resemble the original work.. Massee, George, 1850-1917. New York : Macmillan
RMMCMKH6–.
RMRCD8W9–. Diseases of cultivated plants and trees. Plant diseases; Plants -- Wounds and injuries; Plants, Protection of; Trees -- Diseases and pests. 342 DISEASES OF CULTIVATED PLANTS the seed, which, however, shows no sign of disease, but when sown produces a smutted crop. Seed should be sown that was produced in a crop free from smut. Scilla smut {Ustilago Vaillantii, Tul.) occurs very com- monly in the anthers and ovary of Scilla bifolia and other. Yr,. 102. - Kar of barley attacktd by Lhtilago hordci. species ; Gagea lutea, also in species of Muscari, Believalia, etc. The mycelium of the fungus i
RMMCKCAB–. F"lG. 95.—Gymttoiporangium clavariacforme. I, teleutospore stage on juniper branch; 2, teleutospores; 3, teleutospores ger- minating and producing secondary spores, (7, a ; 4, aecidium stage on pear leaf ; 5, aecidium stage on branch, leaves, and fruit of hawthorn ; 6, aecidiospore germinating. Kigs. i, 4, and 5 reduced, remainder highly mag. Hawthorn cluster-cups (Gymnosporangium clavariaeforme, Jacq.) causes spindle-shaped swellings on the branches of [ttniperus communis, and during the months of April and May numerous flattened, pale-orange, gelatinous masses I
RMRCD8P7–. Diseases of cultivated plants and trees. Plant diseases; Plants -- Wounds and injuries; Plants, Protection of; Trees -- Diseases and pests. 38o DISEASES OF CULTIVATED PLANTS When the object is to grow healthy trees for whatever pur- pose, all diseased trees should be cut down and burned at once, as when the mycelium has once gained an entrance it extends in the trunk from year to year. Polyporus dryadeus (Fries.). This is our largest species of Polyporus, and is not infrequently met with on oak trunks ; the largest specimens usually occur near the ground-line, but it also springs from points
RMMCTMTN–. Fig. i2,.—Sphaerella tabijica, causing heart-rot of orange-globe mangold. Conidial form. Perithecia subglobose, conidia elliptical, hyaline, 5-7 x 35 f, escaping as a gelatinous tendril. As the disease appears somewhat late in the season, it is advisable to lift the crop when it is first observed, before the fungus passes from the leaves into the root. Diseased ' tops' should be collected and buried. It is important not to include diseased roots when storing, and if diseased roots are found when the pits are opened they should not be thrown on the manure heap or into the pig-stye, but buried
RMRCD94H–. Diseases of cultivated plants and trees. Plant diseases; Plants -- Wounds and injuries; Plants, Protection of; Trees -- Diseases and pests. CLAVICEPS 223 Ergot.—This well-known disease, caused by Claviceps piirpicrea (Tul.), is often developed in the ears of various. Fig. b^.—Claviceps purpurea, i, ergot on rye-grass; 2, ergot on rye; 3, section of portion of conidial fruit ; 4, sclerotium or ergot bearing the stalked, ascigerous form of fruit; 5, head of ascigerous fruit showing warted surface, due to projecting mouths of perithecia; the section shoNss perithecia sunk in the fleshy stroma ;
RMMCKC8C–. Fig. 106—It/iyphallas cani litis. Fungus about half nat. size.
RMRCDR2A–. Diseases of cultivated plants and trees. Plant diseases; Plants -- Wounds and injuries; Plants, Protection of; Trees -- Diseases and pests. Fig. I";'^. — Usnea barhnta and Ramalitiafraxhica, lichens "growing on branch of api)le-tree. Reduced. they prove injurious to the extent of preventing the bark from performing its functions, and more especially in afford- ing shelter to numerous forms of insect life which are decidedly injurious to vegetation. Lichens and mosses are killed by spraying with strong Bordeaux mixture or with a. Please note that these images are extracted from scan
RMMCKYHT–. Fig. 33.—Exoascuspruni. i, portion of a branch bearing diseased plums ; 2. a diseased i^luin cut in two. Reduced. and closely resemble crows' nests in appearance, although sometimes much larger in size. The formation of these brooms takes place as follows, according to Smith :— ' I find that a broom results from a prolific development of small twigs on one or a few knotty, swollen parts of a branch. Each central knot we may regard as the position of the bud which was first infected, and from which the broom system took its origin. As one result of the attack of the fungus, the greater number
RMRCD8JE–. Diseases of cultivated plants and trees. Plant diseases; Plants -- Wounds and injuries; Plants, Protection of; Trees -- Diseases and pests. CORYNEUM 455 other causes also are capable of causing gunimosis. I have shown that in one instance the production of large quantities of gum was due to the presence of CladosporUim epiphyllum. In October Vuillemin noted the presence of pycnidia on the dead patches formed by Cory?ieum on the shoots. To these he gave the name of Phyllosticta beyerinckii { = Phyl- losticta persicae, Sacc). The same author also observed in the spring months perithecia nestli
RMMCNJ2Y–. ^^ Fig. 58.— Venturia inaequalis. i, conidial stage (Fusicladium dendriti- f«;«) on apple leaf; 2, 3 and 4, conidial stage; 6, section of perithecium ( Venturia stage) ; 7 and 8, asci and spores of Venturia ; 9, apple twig with Fusicladium stage, as appearing during winter and spring. Figs, i and 9 reduced ; remainder highly mag. practicable. I am not convinced. I believe that it is as practicable to remove the dead shoots from a tree as it is to remove the apples, in fact the Director of the Research Laboratory at Wisley informs me that, out of a batch of badly diseased apple-trees, those t
RMRCD92P–. Diseases of cultivated plants and trees. Plant diseases; Plants -- Wounds and injuries; Plants, Protection of; Trees -- Diseases and pests. CRYPTOMYCES 259 Bark fungus {Tyftipanis conspersa. Fries.) often occurs on living bark of birch and poplar. Ascophores top-shaped, 20-40, springing from a stroma, closed at first, then exposing the black disc, margin sprinkled with a little white meal at first, wall of ascus thick, spores numerous, 1-2X0'5 /x. Spermogonia in minute conceptacles of the stroma, usually. 1^ ^t' 2> Fig. jb. — Tympanisconspcrsa. i, gi'oup of fungi on wood. 2, section of sa
RMMCKBY4–. Fig. i66.—Rhizoglyphiis echinopus, the "bulb mite';' has destroyed the roots of a Hippeastrum bulb. removal of the outside loose scale leaves. This treatment is useful against fungi which follow the attack of the mite. 4. Fumigate with bisulphide of carbon. The bulbs to be treated should be placed in an air-tight receptacle, and a saucer, into which bisulphide of carbon has been poured, placed on the top of them. The bulbs should be left in the vapour for forty-eight hours. This treatment could be usefully extended to imported bulbs, which ought to be examined for the mite. The formula
RMRCD9C4–. Diseases of cultivated plants and trees. Plant diseases; Plants -- Wounds and injuries; Plants, Protection of; Trees -- Diseases and pests. PHYTOPHTHORA 127 Phytophthora omnivora, De Bary {^Phytophthora cactorum, Schrot.). Hartig has paid special attention to this fungus, more especially as a parasite attacking beech seedlings, although as one of its specific names indicates, it also attacks other plants, more especially in the seedling stage, among. Fig. 22>.—Phyiopkfkora ominvora. A beech seedling attacked by the fungus. The dark portion of the stem below the cotyledons, and the blotche
RMMCKCDJ–. Fig. T^.âKhytisma accrinutn. 1, sycamoie leaf with blotches caused'by fungus ; 2, section through a blotch bearing conidia ; 3, ascus with spores, also two para- physes ; 4, an ascosporc. Figs. 2-4 mag. and indirectly. Several large patches are frequently present on a leaf, and as a rule, when the disease is present, nearly every leaf is attacked, hence a considerable area of leaf surface is prevented from doing its work. In addition diseased leaves fall early, and as the disease, unless checked, appears year after year, the tree bet'omes enfeebled owing to lack of food, and badly matured wo
RMRCD9EH–. Diseases of cultivated plants and trees. Plant diseases; Plants -- Wounds and injuries; Plants, Protection of; Trees -- Diseases and pests. 96 DISEASES OF CULTIVATED PLANTS (P. Magnus)—Oedo/nyces leproides (Trabut). It was first observed attacking beetroot, Beta vulgaris, var. ropacea, in the grounds of the School of Agriculture, Rouiba, near Algiers. A portion of a beetroot bearing this disease was once sent for investigation to the Scientific Committee of the Royal. Please note that these images are extracted from scanned page images that may have been digitally enhanced for readability -
RMMCKCAK–. -^r^^- Fig. g-i.—Phra^midium riibi-idafi. i, pustules and teleuto- spores on under surface of raspberry leaf; 2, tcleutospore; .. 1 :.i:—. - chains of warted spores ; 3, section through an accidiuni b, paraphyses ; 4, uredospores. highly mag. Fig. I nat. size, remainder Spraying with potassium sulphide arrests the spread of the disease, li Bordeaux mixture is used it must be diluted, or the foliage will be scorched. Diseased leaves that have fallen should be swept up and burned. XENODOCHUS (Schlecht.) Teleutospores pedicellate, many-celled, cylindrical, brown, forming large blackish spore-cl
RMRCD9H7–. Diseases of cultivated plants and trees. Plant diseases; Plants -- Wounds and injuries; Plants, Protection of; Trees -- Diseases and pests. 46 DISEASES OF CULTIVATED PLANTS free from each other. When the equihbrium of an organism is upset there is often a tendency to revert in some of its characters to an ancestral condition, and flattened or strap- shaped fasciations are probably a reversion to an ancient type of branching. When our higher flowering plants, from some unknown cause, lose their balance, they revert to the long. Fig. 6. —a fasciated example of .1 cultivated carnation. Reduced.
RMMCKC02–. Fig. 161.—Fuligo variaiis. The Plasmodium has crept over the soil in a plant-pot, and formed its mass of spores, which are covered with a yellow crust of lime. Reduced. ous; its Plasmodium often creeps up the stems of living grasses, and forms spore-masses up to 2-3 inches in length and an inch in diameter. These are at first covered with a white crust, which soon falls away, exposing the soot-like mass of spores, which are globose, minutely warted, dusky purple or brownish, 10-13 /x diameter. When produced in considerable quantity, the dense masses of spores are said to injure vegetation by
RMRCD9A7–. Diseases of cultivated plants and trees. Plant diseases; Plants -- Wounds and injuries; Plants, Protection of; Trees -- Diseases and pests. PHYLLACTINIA '53 The fungus is common on many wild plants, as meadow- sweet, yarrow, willow-herbs, geraniums, agrimony, etc.; all such should be kept away from the vicinity of hop fields. Sulphur in some form has proved to be the best fungi- cide. Flowers-of-sulphur should be dredged on the plants during sunshine, as then fumes are given off. Sulphide of. Fig. 2,^.—Phyllactinia siiffulta. i, hazel leaf with patches of mildew; 2, perithecia, a, appendages
RMMCKC9H–. Fig. ()Z.—Melampsora pinito?-qua. i, top of young pine attacked by the aecidium stage; 2, two chains of aecidiospores ; 3, aspen leaf with sori of teleutospores ; 4, section of cushion of teleutospores, still covered by the epidermis. Figs, i and 3 nat. size ; remainder mag. as the fungus appears year after year if damp weather prevails in May and June; this indicates that the fungus is peren- nial in the tissues of the host. In the seed-bed or young plantation the disease usually spreads from a centre, due to infection by wind-borne spores, showing that the aecidiospore stage is capable of
RMRCD9C9–. Diseases of cultivated plants and trees. Plant diseases; Plants -- Wounds and injuries; Plants, Protection of; Trees -- Diseases and pests. 124 DISEASES OF CULTIVATED PLANTS consequent exposure to tropical conditions for so long a period, destroyed the hibernating mycelium ; whereas when a quicker means of transit, due to the replacing of sails by. Fig. 27.—Phytophthora iii/estans. i, a cluster of conidiophores with conidia, emerging through a stoma of the leaf of a potato plant; 2. a free conidium, the contents of which are breaking up into zoospores ; 3. a conidium liberating zoospores ; 4
RMMCKCCE–. Fig. 81.—Psciidopeziza trifolii. i, clover leaf infected ; 2, fungus bursting through epidermis of leaf; 3, ascus with spores, also two paraphyses. Figs. 2 and 3 mag. The ascophores originate in the tissues of the host, usually the leaves. Some are parasites, others saprophytes. Dis- tinguished by the ascophore developing in the tissue of the host, and bursting through to the surface at maturity. Clover leaf spot, caused by Pseudopeziza trifolii (Fckl.), is at times very injurious to the clover {Trifoii2im) and
RMRCD9GT–. Diseases of cultivated plants and trees. Plant diseases; Plants -- Wounds and injuries; Plants, Protection of; Trees -- Diseases and pests. INJURY CAUSED BY NON-PARASITIC ORGANISMS 6i fornian disease is considered to be due to an allied organism, P. californica (Viala and Sauv.). I have shown under the heading ' Orchid Spot,' that the supposed organism considered by Viala and Sauvageau as a member of the Myxomycetes, and named Flas/nodtophora, is merely a diseased condition of the cells of the host-plant, and that brunnisure of the vine and ' orchid spot' are entirely due to physical causes.
RMMCKC4N–. 4^ Fig. 139.—I, Coryneum beyeriiickii ; 2, Cycloconii/m oleaginiiin on olive leaf; 3, fungus of same ; 4, Scoletotrichiim melophthornm ; 5, Trichothecium roseum; 6, Acreino?iiella occulta; 7, Ophiocladium hordei; 8, Meria laricis 9, basidia and spores of same. All except Fig. 2 highly mag. had remained hanging on the tree throughout the winter. These perithecia were considered by Vuillemin as constituting the perfect form of fruit of Coryneum^ and received the name of Ascospoi-a beyermckii { = Asterula beyerinckii, Sacc). The relationship of the three forms mentioned above has not been est
RMRCDR27–. Diseases of cultivated plants and trees. Plant diseases; Plants -- Wounds and injuries; Plants, Protection of; Trees -- Diseases and pests. 5IO DISEASES OF CULTIVATED PLANTS Coal and peat, like other organic matter, are liable to decomposition as soon as conditions are presented suitable for the life of aerobic organisms. The carbon is then once more liberated, in the form of CO.,, to play its role in the life- cycle. It is thus conceivable that the vast supplies of carbon locked up in the world's coal-fields may become available for plant nutrition without the intervention of direct combust
RMMCMN43–. Fig. 16.—Lentiniis cyathus, an agaric springing from a sclerotium ; the latter shown in section. One-sixth nat. size. conidial phases of the groups previously enumerated. Large numbers of these are amongst the most destructive of parasites. Although spores, in the wider sense of the term, are the most general forms of reproduction, conidia or summer-
RMRCD9BB–. Diseases of cultivated plants and trees. Plant diseases; Plants -- Wounds and injuries; Plants, Protection of; Trees -- Diseases and pests. Fig. 31. I, lixoascus deformans, sliowing asci in various stages of development burslinR through the cuticle of the leaf; 2, ascus of Exoanus pruni, showing stalk-cell at base of ascus, and eight spores; 3, ascus of Taphritia aiirca filled with secondary spores produced by budding of the ascospores ; 4, surface view of niycelium of Taphrina Sadcbcckii on leaf of Almes glutinosa ; 5, differentiation of fertile or ascogenous hyphae from vegetative hyphae o
RMMCKC97–. Fig. ioo.—Gcrniin.iiing spores of species of Ustilaginaceae. I, Ustilago ariindinellae; 2, Tillctia decipiens, the secondary spores producing tertiary spores ; 3, Tilletia sonata. All highly mag. (.After Brefeld.) known as 'smuts' and 'bunts.' Teleutospores only are known in this group. In some instances infection takes place in the earliest seed- ling stage of the host-plant, the spores being present in the soil, or adhering to the seed when sown, as in oats. In other instances infet tion occurs in the flower, spores being deposited on the stigma, and a myceliimi is found in the ovary, as i
RMRCD931–. Diseases of cultivated plants and trees. Plant diseases; Plants -- Wounds and injuries; Plants, Protection of; Trees -- Diseases and pests. 254 DISEASES Of^ CULTIVATED PLANTS RHIZINA (Fries.) Ascophore entirely sessile, expanded from the first, fleshy, under surface furnished with numerous tufts of hyphae; asci cylindrical, 8-spored, spores elongated, continuous, hyaline. Readily recognised by the dark-brown, crust-like ascophore, furnished on the under surface with numerous rhizoids or tufts of hyphae, by which it is fixed to the substratum. Rhizina inflata (Quel.) is a fairly common Britis
RMMCX0FM–. Fig. 37.—Sphaerotheca mors-uvae. 1, showing mildew on leaf and fruit ; 2, winter stage on a shoot ; 3, perithecium or winter fruit; 4, ascus con- taining spores ; 5, a chain of conidia or summer fruit ; 6, conidia showing fibrosin bodies in their interior; 7, a branch that has been injured by aphides (green fly) at the tip. The recurved spines and brown colour are characteristic. Figs, i, 2, and 7, nat. size ; remainder highly mag. when an autumnal expansion of buds follows early pruning. As the season advances the white mildew, which at first resembles in general appearance the well-known h
RMRCD963–. Diseases of cultivated plants and trees. Plant diseases; Plants -- Wounds and injuries; Plants, Protection of; Trees -- Diseases and pests. GNOMONIA 20I phore, 14-20X1-1-5 /t. Perithecia of ascigerous form with an ostiolum or beak projecting beyond surface of leaf; asci 8-spored; spores liyaline, narrowly ovate, i-septate below the middle, 16-18 X 5-6 /x. Collecting and burning all the hanging leaves during winter is the only practical method of stamping out the disease. This practice, however, should be general in an infected district, otherwise it is of little avail, as the spores are blow
RMMCKCBE–.
RMRCD8T2–. Diseases of cultivated plants and trees. Plant diseases; Plants -- Wounds and injuries; Plants, Protection of; Trees -- Diseases and pests. AGARICACEAE 353 kind of root-rot which eventually kills the vine. So far as I am aware there is no record of injury caused to cultivated plants in this country by this fungus, yet as in many other well-proved cases, a fungus, for some hitherto unknown reason, suddenly assumes the character of a destructive parasite. The ' Stinkhorn,' as Ithyphallus is called by country people, is often a great nuisance when it grows in hedgerows or under bushes in garden
RMMCKCBF–. Fig. 88.—Puccinia pringshcimiana. i, portion of gooseberry leaf with three aecidia or ' cluster-cups ' ; 2, section through a ' cluster-cup'; a, spores produced in chains; b, wall or peridium ; c, epidermis of host; rf, middle cells of leaf; e, mycelium of fungus ; 3, portion of sedge leaf bearing sori of teleutospores ; 4, portion of same ; 5, teleutospores. 6, uredo- spores. Fig. i nat. size, and remainder variously mag. thickened, roundish or truncate, base often narrowed, smooth, brown, 35-50 x 15-20 /x; pedicel rigid, persistent. No remedial measures known. It is advisable to pick infec
RMRCD8J8–. Diseases of cultivated plants and trees. Plant diseases; Plants -- Wounds and injuries; Plants, Protection of; Trees -- Diseases and pests. CLADOSPORIUM 471 stem of diseased plants. The young fruit is also sometimes attacked. The fungus is Cladosporiiim fiilvum (Cke.) The conidiophores are densely crowded, and emerge through the cuticle in clusters. They are usually sparingly branched, septate, and nodulose, bearing a few conidia near the apex, tinged brown; conidia elliptic-oblong, i-septate, translucent, tawny-brown, 10-20X4-6 /x. Spray with a dilute solution of potassium sulphide, or with
RMMCNC90–. 1-"k;. I.—Leaf mould infested with mycelium, turned out of a plant pot, in which a liegonia was planted. The mycelium attacked the root of the Begonia and killed it. Reduced. whether it is necessary to have uncultivated headlands at all, I leave for the practical farmer to decide. Some years ago, a batch of begonias that had been potted in leaf-mould went 'off in a mysterious manner. On investigation it was discovered that the leaf-mould in which the begonias were planted was overrun by a dense mass of white mycelium. As a rule leaf-mould contains mycelium, and in this particular instan
RMRCD9J2–. Diseases of cultivated plants and trees. Plant diseases; Plants -- Wounds and injuries; Plants, Protection of; Trees -- Diseases and pests. 26 DISEASES OF CULTIVATED PLANTS in the field. More than this, I have proved, on more than one occasion, that a fungus disease which has proved destructive to a crop has originated in the first instance from spores produced on weeds growing on the borders of the field. A celebrated professor of agriculture, hailing from one of our universities, has pronounced the above statement to be a mycological myth, adding as a rider, that it was impractic- able to
RMMCMH8F–. Fig. 22.—Rhizopus nigricans, i. portion of fungus; 2, zygo- spore; 3, spores; 4, Synchytrium taraxici; resting-spore in epidermal cell ; 5, resting-spore liberating a mass of sporangia ; 6, a sporangium liberating zoospores. All highly mag. Synchy trill in Niessii (Bubak) forms warts on the leaves of Gagea and Ornithogalum utjibellatum. The warts are at first dirty white, bounded by a dark brown line. Resting-spores globose, single or 2-10, sometimes up to 20 in inflated or spindle-shaped epidermal cells. Bubak, F., Sep. Osterr. Bot. Zeitschr., No. 7, Ser. 2 (1898).
RMRCD92M–. Diseases of cultivated plants and trees. Plant diseases; Plants -- Wounds and injuries; Plants, Protection of; Trees -- Diseases and pests. SCLEROTINIA 261 vine directly. Istvanffi has written a very detailed account, profusely illustrated, of the vine sclerotinia.. Fig. ^-j.—Sclerotinia fuckeliana. i, vine leaf with Botrytis form of fungus ; 2, conidiophores of Botrytis ; 3, a head or cluster of conidia ; 4, sclerotia bearing Botrytis form of fruit ; 5, asclerotium bearing two ascophores ; 6, like fig. 5, on a larger scale ; 7, a shrivelled grape with sclerotia ; 8, ascus with spores. All e
RMMCKC41–. Fig. 140. — Cladosporinmfulvum. i, under surface of a diseased leaf; 2, a cluster of conidiophores bearing conidia, highly mag, half Strength Bordeaux mixture. Spraying, however, is cl but little use unless commenced at an early stage of the dis- ease. Remove and burn plants that are badly diseased, as the spores diffuse quickly, and an epidemic that cannot be checked is the result of negligence. Gummosis of Prunus japonica {Cladosporium epiphylbun, Fr.) either killed or severely injured a considerable number of examples of the beautiful flowering shrub, Primus japonica, growing in Kew Garde
RMRCD9AE–. Diseases of cultivated plants and trees. Plant diseases; Plants -- Wounds and injuries; Plants, Protection of; Trees -- Diseases and pests. SPHAEROTHECA 147 dispersed by wind, rain, insects, birds, etc., and each one that ahghts on a young, growing part of a gooseberry bush is capable of infecting the plant, and starting a new centre of disease. This mode of infection may continue until late in the autumn, under favourable weather conditions, or. Fig. 37.—Sphaerotheca mors-uvae. 1, showing mildew on leaf and fruit ; 2, winter stage on a shoot ; 3, perithecium or winter fruit; 4, ascus con- t
RMMCKC2A–. Fig. 149.—Fusarium heterosporum. i, portion of an ear of rye showing diseased grains ; 2, diseased grains; 3. portion of a diseased grain showing the dense clusters of spores on its surface ; 4, spores. Fig. I nat. size ; remainder mag. Red mould of Wheat {Fusarium culmorum, W. G. Sm.) is said by Smith to attack wheat, forming cream-coloured, yellow or orange, subgelatinous masses on the ear, gluing the various parts together and preventing the development of the grain. The conidia are said to be larger than those of F. heterosporutn, fusiform, 3-5-septate, orange, soon break- ing up at the
RMRCD8TM–. Diseases of cultivated plants and trees. Plant diseases; Plants -- Wounds and injuries; Plants, Protection of; Trees -- Diseases and pests. UROCYSTIS 349 is recommended that onions should be transplanted, because at a certain age the plants cannot be infected, even if spores are in the ground. Diseased plants should be collected when thinning is in operation. Thaxter, A?in. Rep. Conti. Expt. Stat., p. 129 (1890). •51 j. Fig. 105.—Urocystis colchici. i, portion of infected leaf ; 2, a single sorus, slightly mag. ; 3, spores, highly mag. ColcMcium smut {Urocysiis cokhici, Rab.) forms long rows
RMMCKC96–. Fig. 103.â Tilletia tritici. I, ear of wheat diseased ; 2, spore ; 3 and 4, spores germinating and producing a gcrm-"tul)e, bearing a cluster of secondary spores at its apex ; 5, two secondary spores tiiat iiavc conjugated or become united by a siiort transverse neck ; one of the secondary spores has produced a conidium. Figs. 2-5 highly mag. (Figs. 3-5, after Brefeld.) Wheat sown in the spring is always more smutted than when sown in the autumn. Brefeld, Uutcrs. aus dcm Gesatnn. dcr Mykol., 5, p. 146. Tilletia levis, Kiihn {â =Tille/ia foetefis, Arthur), develops in the ovary of wheat,
RMRCD94P–. Diseases of cultivated plants and trees. Plant diseases; Plants -- Wounds and injuries; Plants, Protection of; Trees -- Diseases and pests. Fig. 62.—Mycosp/iaere/la sentina. i, pear leaf attacked b)' fungus, nat. size; 2, conidia of Septoria form ; 3, ascus and free spores of ascigerous form. 2 and 3 highly mag. proved by Klebahn to be the conidial condition of the asci- gerous fungus, Mycosphaerella sentina (Schroter). The injury is undoubtedly caused by the conidial form of the fungus, the ascigerous condition developing only on dead leaves that have been lying on the ground throughout the
RMMCMHNF–. 'S«»fefc v.^ Fig. 21.âSync/iytrium solani. i, section through portion of a young potato sprout, showing many of the peripheral cells infected by the zoospores of the fungus. The central cell that is dividing has escaped infection ; 2, section through a portion of a scab, showing mature resting-spores deep down in the tissue and the youngest at the periphery; 3, a young resting-spore not yet enclosed in a thick wall ; 4, 5, and 7, mature resting-spores ; 6, a resting-spore germinat- ing, i-ciliate zoospores escaping. All highly mng. spore, containing the zoospores, was extruded, the zoospor
RMRCD8K2–. Diseases of cultivated plants and trees. Plant diseases; Plants -- Wounds and injuries; Plants, Protection of; Trees -- Diseases and pests. 442 DISEASES OF CULTIVATED PLANTS Pods that are severely attacked are often contorted or twisted, and in such instances the mycelium frequently passes quite through the pod and infects the beans. The conidiophores burst through the epidermis in tufts on the diseased spots, cylindrical, simple, 45-55 /* long; conidia apical, oblong, ends rounded, straight or curved, hyaline, i5-i9X3'5-5"5 Z^-. Spines few in number, or sometimes absent, dark coloured.
RMMCKC6P–. Fig. 117.—Polyporus bctiilini/s. Fungus and section of same, reduced. broken off. According to Hartig, during the decomposition of the wood by the mycelium, oblong yellowish or whitish blotches appear in the otherwise sound heart-wood. The cell-walls of these white blotches have been converted into cellulose, and have become isolated by the solution of the middle lamella. These patches are gradually dissolved, and holes surrounded by hard wood are formed. Sporophore bracket-shaped or hoof-shaped, 7-12 in. across, attached by a broad base, becoming corky in substance,
RMRCD9E6–. Diseases of cultivated plants and trees. Plant diseases; Plants -- Wounds and injuries; Plants, Protection of; Trees -- Diseases and pests. SYNCHYTRIUM 99 so that eventually, cells that formed the peripheral or outside row are deeply buried in the tumour, and resting-spores are. Fig. 20.—Synchytrium solani; Black scab of potato. consequently met with buried deeply in the flesh of the tumour. It will be observed, however, in examining a section of a wart or tumour, that the oldest and most perfectly. Please note that these images are extracted from scanned page images that may have been digit
RMMCKC7Y–. Fig. 110. - Agaricus mellcus. Base of stem of young Scots fir killed by the fungus. A portion of the stem is cut away to show the dense white layers of mycelium under the bark. These rhizomorphs radiate in every direction in the soil, growing by the tip only, and eventually attack the roots of other trees, by dissolving the cortex and giving origin to a sheet of white mycelium between the wood and the bark as described above.
RMRCD8Y7–. Diseases of cultivated plants and trees. Plant diseases; Plants -- Wounds and injuries; Plants, Protection of; Trees -- Diseases and pests. 314 DISEASES OF CULTIVATED PLANTS the pustules are pale orange, and irregularly scattered. Later in the season small black clusters of teleutospores appear on the under surface of the leaves. Aecidiospores orange, aculeolate, 20-28 yu, diam., paraphyses clavate, orange. Uredospores orange, aculeate, 16-22 fi. Teleutospores oblong, apiculate, warted, 5-10 septate, black and opaque, 90-140 X 20-35 /x, pedicel thickened below.. -^r^^- Fig. g-i.—Phra^midium
RMMCKBXT–. Fig. 167. Eelworms. i, male of Tylenchus. devastatrix (after Ritzema Bos) ; 2, female of Heterodera ntdicico/a ; 3, egg of same ; 4. section of portion of a tomato root, showing two females of Heterodera radicicola in section, one of which contains numerous eggs. and practical method at the. present time of exterminating nematodes in greenhouses is by heating the soil by means of steam. This can be accomplished without much expense, providing proper attention is paid to the method of applying the steam.
RMRCD90F–. Diseases of cultivated plants and trees. Plant diseases; Plants -- Wounds and injuries; Plants, Protection of; Trees -- Diseases and pests. Fig. 88.—Puccinia pringshcimiana. i, portion of gooseberry leaf with three aecidia or ' cluster-cups ' ; 2, section through a ' cluster-cup'; a, spores produced in chains; b, wall or peridium ; c, epidermis of host; rf, middle cells of leaf; e, mycelium of fungus ; 3, portion of sedge leaf bearing sori of teleutospores ; 4, portion of same ; 5, teleutospores. 6, uredo- spores. Fig. i nat. size, and remainder variously mag. thickened, roundish or truncate
RMMCMJKR–. â e:
RMRCD8WG–. Diseases of cultivated plants and trees. Plant diseases; Plants -- Wounds and injuries; Plants, Protection of; Trees -- Diseases and pests. 340 DISEASES OF CULTIVATED PLANTS Maize smut {Usti/ago viaydis, D. C.) attacks maize or Indian corn, and often seriously interferes with the yield. It forms marked deformations on practically every part of the plant, under the form of large galls or blisters of a whitish colour. When approaching maturity the spore masses appear. Pig. ioi. — Usiilago avcitac. i, a ' snuilti-d ' car of oats ; 2, spores ; 3, gi minating spores ; 4, secondary spores conjugat
RMMCNDHW–. Fig. 59.— VenturiiZ pirina. i, conidial form of fungus on pear leaf; 2, conidial form of fungus on pear, causing scab ; 3, fruit of conidial stage, highly mag. shrinking and depression of a patch of bark, on which longi- tudinal and transverse cracks appear. When the wound becomes open, black pycnidia appear, followed by the asci- gerous form of fruit. Pyenidia very minute, o-2-o'4 mm. diam., conidia colour- less, fusiform, 7-9x2-2-5 jx, on the tips of branched conidio- phores. Perithecia depressed globose, with a long, stout beak; O
RMRCD917–. Diseases of cultivated plants and trees. Plant diseases; Plants -- Wounds and injuries; Plants, Protection of; Trees -- Diseases and pests. UROMYCES 295 of which often remain in the dead leaves until the following spring, when they germinate and infect any of the host- plants within reach. Uromyces betae is very common on wild beet {Beta ftiaritima), which is the origin of sugar beet, beetroot, and mangold, and the fungus common on the wild beet has passed on to the various cultivated forms. In addition to this, these cultivated forms, now growing in countries where the wild beet does not ex
RMMCMDBX–.
RMRCD995–. Diseases of cultivated plants and trees. Plant diseases; Plants -- Wounds and injuries; Plants, Protection of; Trees -- Diseases and pests. Fig. 43.—Eutypellii prunastri. i, portion of stem of young plum-tree show- ing conidial stage of fungus ; 2, portion showing a.scigcrous stage on the dead bark. especially when the soil is inclined to be stiff. Under such circumstances numerous large lenticels are formed on the stem, and I have found by experiment that if spores of the conidial condition of the fungus are applied to such lenticels during damp weather infection follows. To guard against i
RMMCKC2P–. Fig. 146.—I, Cercospora melonis, a leaf of cucumber showing early stage ot disease ; 2, sporophores emerging from a stoma, and bearing spores, mag. ; 3, spore, highly mag. it suddenly appeared in the houses of a grower located at some distance from the nearest known infected area. The explanation was as follows. This grower had sent a consign- ment of cucumbers to Covent Garden, and by some mistake his own empty packing-cases or ' flats' were not returned, but instead, those belonging to another grower whose plants were diseased. Spores of the fungus had been conveyed from one district to an
RMRCD8P1–. Diseases of cultivated plants and trees. Plant diseases; Plants -- Wounds and injuries; Plants, Protection of; Trees -- Diseases and pests. 584 DISEASES OF CULTIVATED PLANTS independent fungus and called Ptychogaster aurauiiacus. These structures resemble in general appearance young spore- producing plants, and bear conidia in receptacles ni the flesh, but do not form tubes bearing true spores.. KiG. 119.—Poh'porus sII1/1/re 14s. Block of white spruce wood showing injury c;iusccl by this fungus. (After Schrenk.) Pohporiis si/uamosus (Fries.). This very common fungus occurs abundantly on dead
RMMCKC2K–. Fig. 147.—Cercospora apii. i, celery leaf attacked by the fungus ; 2, fruit of fungus, highly mag. hyaline, almost cylindrical, a little thickened at one end, 3-10 septate, 50-80 X4 /x. Spraying with amraoniacal carbonate of copper solution is most efficient in checking the disease, if applied before the disease has advanced too far. The spores on diseased leaves live through the winter, and are capable of infecting a crop the following season, hence the leaves should be gathered and burned. Some portions of leaves, however, are certain to remain on the ground, and rotation of crops, where p
RMRCD8TR–. Diseases of cultivated plants and trees. Plant diseases; Plants -- Wounds and injuries; Plants, Protection of; Trees -- Diseases and pests. 348 DISEASES OF CULTIVATED PLANTS Onion smut {UrocysHs cepulae. Frost) is only known to attack cultivated onions, and develops during the seedling stage. As a rule the first leaf shows the disease before the second leaf appears : the disease attacks the leaves in the order of their appearance. The outer coat of the bulb is. P'iG. 104. — Urocystis occulta. i, upper part of rye plant diseased ; 2, spores, one of w hich has germinated and produced a cluster
RMMCKCAA–. Fig. 94.—Xenodochtiscarbonarius. i, teleutospore pustules on Burnet saxifrage, nat. size; 2, a single teleutospore, highly mag, ; 3, a chain of uredospores, highly mag. Teleutospores cylindrical or worm-like, often curved, composed of 10-20 globose cells, much constricted at the septa, smooth or minutely warted towards the apex, dark brown; individual cells 15-20 /x diam.; stalk short, hyaline. GYMNOSPORANGIUM (Hedw.) Teleutospores forming large subgelatinous masses, oozing out from the bark of the matrix (always Junipers in this
RMRCD969–. Diseases of cultivated plants and trees. Plant diseases; Plants -- Wounds and injuries; Plants, Protection of; Trees -- Diseases and pests. 200 DISEASES OF CULTIVATED PLANTS numerous minute, erumpent perithecia situated on large dis- coloured patches. The mycelium of the conidial form spreads rapidly in the tissues of the leaf and passes into the leafstalk, cutting off the supply of food, consequently the leaves are killed early in the season, and as in all such cases where leaves are killed early in the season through lack of food, remain hanging on the tree throughout the winter, and even.
RMMCKC3T–. Fig. 142.—Spondylocladitim atrovircns. i, po- tato showing patches of the fungus and micro- sclerotia ; 2, fruiting condition of the fungus ; 3, micro-sclerotium. 2 and 3 mag. dingy olive or brownish, up to 400 /x high; conidia elongato- ovate, apex narrowed, 5-7-septate, arranged in whorls, coloured like the stem, 30-50X6-9 i. Potatoes bearing sclerotia or showing the sunken areas characteristic of the disease, should not be used for sets. Land that has produced a diseased crop should not be again planted with potatoes for some years. Lime or kainit would probably assist in destroying scle
RMRCE2E7–. Diseases of cultivated plants and trees. Plant diseases; Plants -- Wounds and injuries; Plants, Protection of; Trees -- Diseases and pests. 56: DISEASES OF CULTIVATED PLANTS more; lobes undulate and contorted, smooth (not corrugated), base firmer, plicate, pale pinkish-yellow; spores subglobose, apiculate, 7-9 ix. Other species, as T. mesenterica, etc., sometimes occur on living trees.. (Afur A. (laike.) Eoot rot of tobacco. — Dr. W. ^^^ (iill)ert has just issued an exhaustive account of Thielavia basicola, which he has proved. Please note that these images are extracted from scanned page im
RMMCTWBB–. FlC. 63. — I, Sphacrulina taxi, on yew lc;if, slightly mag. ; 2, section of pcrithecium. slightly mag. ; 3, ascus containing spores, highly mag. ; 4, free ascospores, highly mag. If the disease attacks a tree for two or three years in succession it is usually killed outright. Fortunately this is not a common disease, or at all events it is not very frequently recorded. I have seen it at work in Cornwall, and also in Yorkshire, where a number of fine yew-trees growing in a churchyard were being killed. Mr. F. Moore of Glasnevin informed me that he had noticed the disease in three counties in
RMRCD8RR–. Diseases of cultivated plants and trees. Plant diseases; Plants -- Wounds and injuries; Plants, Protection of; Trees -- Diseases and pests. 356 DISEASES OF CULTIVATED PLANTS wood and the bark, or pass out through the bark and form rhizomorphs on its surface, which in the case of roots pass into the soil After the death of the tree the shrinkage of the bark affords space for the further development of these. Fig. 109.—Armillaria incllea. 2, section of fungus, a, pileus ; b, gills ; c, ring ; </, black, cordlike strands of myceiiiini; 3, basidium, a, accompanied by paraphyses ; 4, portion o
RMMCMF94–. Fig. 26.—Plasmopara viticola. i, under surface of a vine leaf showing white patches of mildew ; 2, group of conidiospores bearing numerous conidia ; 3, three conidia more highly mag.; 4, conidia containing zoospores, in b, two zoospores have escaped from the conidium ; 5, mature oospore or nsting-spore ; 6, an oospore germinating and producing a conidiopiiore (after Prillieu.x) ; 7, autumnal form of conidiophore bearing a few large conidia (after Prillieu.x). Fig. i reduced, remainder highly mag. Oospores are produced in abundance in the dying portions of the plant. When a plant is attacked,
RMRCD8PN–. Diseases of cultivated plants and trees. Plant diseases; Plants -- Wounds and injuries; Plants, Protection of; Trees -- Diseases and pests. 372 DISEASES OF CULTIVATED PLANTS of a brown, felt-like substance, used in the production of a great variety of articles, as purses, chest-preservers, slippers, bags, etc. A good collection of articles made from this substance are on view in No. 2 Museum, Royal Botanic Gardens, Kew. Tubeuf states that at one time the sporo- phores of Fomes fomentarius, the tinder fungus, were so numerous and large that for their collection for manufacture of caps, gloves
RMMCRFNW–. Fig. 51.—Hypomyces perniciosKs. i, mushrooms deformed by the fungus, half nat. size ; 2, conidia of the fungus, highly mag. gallons of water; this should be repeated twice at an interval of about three weeks. Jour71. Bd. Agric. Leaflet, No. 139. Magnus, Verh. Ges. Deutsch. nat. u. Aerzte, 60, p. 246. Stapf, Verh. zool.-hot. Geseli., 39. p. 617. SPHAERELLA (Ces. and De Not.) Perithecia membranaceous, subglobose or depressed, covered by the epidermis or bursting through ; asci 8-spored ; spores elongated, i-septate, hyaline; paraphyses absent. N
RMRCD8NT–. Diseases of cultivated plants and trees. Plant diseases; Plants -- Wounds and injuries; Plants, Protection of; Trees -- Diseases and pests. POLYPORUS 385 yellowish-white with darker adpressed scales, tubes short, pores large, irregular in form, whitish, stem short, base black, pores running down the stem. Substance rather soft. A large fungus, pilei 4-8 in. across, sometimes much larger. Greville describes one which measured 7 ft. 5 in. in circumference, and weighed after having been cut four days, 34 lb. It was only four weeks in attaining the above size, gaining thus an acquisition of weig
RMMCKCE9–. Fig. 68.—Swede, lower half covered with mycelium of Rhizoctonia violacca. packed, more or less parallel, septate hyphae, which spreads out above into a subglobose head of compactly interwoven tissue; and at the lower or basal end, again expanding into a large mass of compactly interwoven hyphae, buried in the tissue of the host. It is the mycelium of the micro-sclerotia that alone enters the living tissues and kills the host; the superficial felt of mycelium does not send mycelium into the tissues, and is so loosely attached that it can usually be rubbed off with the fingers. The second type
RMRCD97F–. Diseases of cultivated plants and trees. Plant diseases; Plants -- Wounds and injuries; Plants, Protection of; Trees -- Diseases and pests. 184 DISEASES OF CULTIVATED PLANTS I have also seen it on the gooseberry in such quantity as to kill the branches. The fungus is a wound-parasite, and it frequently follows on the wounds caused by American blight [ScJiizoneura ianosa), since the advent of which, canker has been much. PJ' >-'"i;.;i. Please note that these images are extracted from scanned page images that may have been digitally enhanced for readability - coloration and appearance
RMMCKCCX–. Fig. 79.—Sclerotinia ur7iula. i, chain of conidiain young stage ; 2, chain of conidia at maturity ; the narrow necks or disjunctors deliquesce, and set the conidia at liberty; 3, ascophores springing from mummified fruits ; 4, ascus with spores ; 5, paraphyses. All figs except 3 mag. This is a very difficult disease to combat; if diseased patches are observed while yet quite small in area, the clover should be cut, and after remaining for some time to dry, some dry litter should be spread over the diseased patch, and set on fire. By this means all the sclerotia are destroyed. Clover should n
RMRCD9DK–. Diseases of cultivated plants and trees. Plant diseases; Plants -- Wounds and injuries; Plants, Protection of; Trees -- Diseases and pests. â e:. 'S«»fefc v.^ Fig. 21.âSync/iytrium solani. i, section through portion of a young potato sprout, showing many of the peripheral cells infected by the zoospores of the fungus. The central cell that is dividing has escaped infection ; 2, section through a portion of a scab, showing mature resting-spores deep down in the tissue and the youngest at the periphery; 3, a young resting-spore not yet enclosed in a thick wall ; 4, 5, and 7, mature resting-s
Download Confirmation
Please complete the form below. The information provided will be included in your download confirmation