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Since the origin of powdery mildew in the Late Cretaceous period and ancestral powdery mildew were first unearthed on broad-leaved deciduous trees in the high latitudes of the Northern Hemisphere, that continued further speciation while spreading southward in the Paleogene and Neogene periods[1], numerous reports have been recorded globally. As a result, comprehensive studies on elucidating powdery mildew disease were established. Powdery mildews are obligate biotrophic ectoparasites classified in Leotiomycetes (with primitive cup-fungi), the order Erysiphales, and the family Erysiphaceae. This includes 26 genera, > 900 species presently known worldwide[2,3]. Powdery mildews are generally white and dusty in the conidial state. They live epiphytically, coat, exclusively feed on living epidermal cells, and fulfill their (a)sexual life cycle on leaf and small stem surfaces. They primarily attack young shoots, leaves, and inflorescences. As a result, the fruit set is reduced, and those that reach maturity are small, crunched, and cracked. The plant becomes stunted or chlorotic and has severe defoliation. This disease can spread rapidly and is prevalent in high humidity but does not require moist conditions to germinate, grow, establish, and infect[4−6], and they usually thrive well even under warm and dry conditions.
The intensive and extensive cultivation of crops and other plant species has resulted in large-scale perpetuation, build-up, and dissemination of powdery mildews on plant species in Southeast Asia (SEA) and worldwide. In addition, Southeast Asia generally has warm, humid, and cooler temperatures in highland areas, which is favorable for powdery mildew disease. This review provides a brief synthesis of the current understanding of powdery mildew disease in Southeast Asia, emphasizing its reported powdery mildew species, host range, impact, and sources of resistance. Moreover, research opportunities would contribute to a better understanding of the powdery mildew pathogen.
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Of the 26 currently accepted genera[3,7,8] and > 900 species[2] of the Erysiphaceace or powdery mildews, so far 14 genera (Blumeria, Brasiliomyces, Cystotheca, Erysiphe, Fibroidium, Golovinomyces, Leveillula, Microidium, Odiopsis, Oidium, Ovulariopsis, Phyllactinia, Podosphaera, Pseudoidium,) and 96 species (based on currently accepted species)[9,10] were reported and listed from Southeast Asia (Table 1). The genus Erysiphe had the most number of species (25) reported. In terms of frequency of reports, Oidium sp. had the greatest number of host reports with occurrences recorded in Thailand, Brunei Darrusalam, Myanmar, Cambodia, Indonesia, Laos, Malaysia, Philippines, Singapore, and Vietnam (Table 1). Nevertheless, some of these records were only up to the genus level. Hence, future sampling of powdery mildews would aid in verifying the species of Oidium infecting various plants in SEA.
Table 1. Southeast Asian (SEA) records of powdery mildew species associated with various plant species.
Powdery mildew species
(previously reported as)Plant species Country References Blumeria graminis Triticum glaucum Myanmar [13] Brasiliomyces chiangmaiensis Dalbergia cultrata Thailand [2] Dalbergia cultrata var. cultrata Thailand [14] Cystotheca (syn. Setoidium castanopsidis) Castanopsis javanica Indonesia [15] Cystotheca tjibodensis Castanopsis argentea Indonesia [16] Erysiphe asiatica Castanopsis diversifolia, Castanopsis echinocarpa Thailand [17] Erysiphe baliensis Gliricidia sepium Indonesia [18] Desmodium triflorum Thailand [19] Erysiphe boehmeriae Boehmeria siamensis Thailand [20] Erysiphe caricae-papayae Carica papaya Thailand [21] Erysiphe cruciferarum Brassica juncea Vietnam [22] Brassica parachinensis, Cleome chelidonii Thailand [23] Erysiphe diffusa Glycine max Vietnam [24] Erysiphe diffusa (syn. Oidium caricae) Carica papaya Indonesia [7] Erysiphe elevata Eucalyptus camaldulensis Thailand [20] Erysiphe fernandoae Fernandoa adenophylla Thailand [25] Erysiphe heraclei Hydrocotyle javanica Thailand [23] Apiaceae, Coriandrum sativum Myanmar [13] Erysiphe javanica Castanopsis javanica Indonesia [26] Erysiphe kydiae-calycinae Kydia calycina Thailand [20] Erysiphe lespedezae Bauhinia purpurea Thailand [27] Phanera purpurea Thailand [19] Erysiphe liquidambaris (syn. Erysiphe liquidambaris var. acalycinae) Liquidambar acalycina Thailand [28] Erysiphe monoperidiata Castanopsis argyrophylla, Castanopsis calathiformis, Castanopsis indica, Castanopsis tribuloides, Lithocarpus elegans, Lithocarpus polystachyus Thailand [2,17] Erysiphe mori Tectona grandis Thailand [28, 29] Erysiphe necator (syn. Erysiphe necator var. necator) Vitis vinifera Thailand [28] Erysiphe necator (syn. Oidium tuckeri) Vitis vinifera Cambodia, Indonesia, Malaysia, Myanmar, Vietnam [7] Thailand [7,30] Erysiphe necator (syn. Uncinula necator) Fragaria × ananassa Philippines [31] Vitis vinifera Philippines [32,33] Erysiphe nyctaginacearum Mirabilis jalapa Indonesia [2] Thailand [20] Erysiphe pisi (syn. Erysiphe pisi var. pisi) Pisum sativum Thailand [19] Pisum arvense; Pisum sativum Myanmar [13] Erysiphe platani (syn. Microsphaera platani) Platanus sp. Brunei Darussalam [34] Erysiphe polygoni Phaseolus aureus, Pisum sativum, Vigna sinensis Cambodia [35] Calendula sp Thailand [36] Antigonon leptopus, Muehlenbeckia platyclada, Polygonum odoratum Thailand [20] Clitoria ternatea Vietnam [37] Citrus nohilis Philippines [38] Vigna radiata, Pisum sativum, Phaseolus aureus, Phaseolus radiatus Philippines [31,39−42] Crotolaria incana, Crotolaria mucronata, Crotolaria pallida, Crotolaria saltiana, Heliotropium indicum, Cleome rutidosperma Philippines [43] Vigna sesquipedalis, Vigna sinensis x Vigna sesquipedalis Philippines [44] Erysiphe pseudolonicerae Cyclea barbata Thailand [20] Erysiphe quercicola Acacia auriculiformis Thailand [45] Cassia fistula, Castanopsis argyrophylla, Hodgsonia macrocarpa, Kydia calycina, Jatropha curcas, Mallotus philippinensis, Mimosa pudica, Tamarindus indica, Ziziphus jujuba Thailand [46] Hevea brasiliensis Thailand [46−48] Quercus sp. Thailand [47−50] Vietnam [48,51] Malaysia [47,48] Bauhinia purpurea Indonesia [47,52] Erysiphe quercicola (syn. Oidium citri) Citrus limon, Citrus sinensis Timor-Leste, Malaysia [47,53] Citrus reticulata Vietnam [48,51] Timor-Leste [53] Citrus sp. Myanmar [13] Erysiphe quercicola (syn. Oidium bixae) Bixa orellana, Thailand [47,53] Indonesia [54] Erysiphe quercicola (syn. Oidium mangiferae) Mangifera indica Thailand [47,53] Myanmar [13] Erysiphe sidae Sida rhombifolia Indonesia [18] Erysiphe tectonae (syn. Uncinula tectonae) Tectona grandis Thailand [28,29] Myanmar [7,8,13] Erysiphe trifoliorum Aeschynomene americana
var. Americana, Sesbania grandiflora, Tamarindus indicaThailand [19] Erysiphe sp. Aristolochia indica, Viburnum inopinatum, Wrightia arborea, Luffa acutangula, Ostodes paniculata Thailand [23] Clitoria ternatea, Indigofera dosua, Indigofera linnaei, Lithocarpus lindleyanus, Lithocarpus vestitus, Microtoena insuavis, Mucuna bracteata, Ocimum sanctum, Pueraria mirifica, Pueraria wallichii, Thailand [19] Ficus subincisa Thailand [20] Nicotiana tabacum Thailand [7,30] Vigna sinensis, Vigna unguiculata, Sesasum orientale, Phaseolus vulgaris Philippines [40,55] Solanum lycopersicum Philippines [40,55−57] Carica papaya Philippines [40,55,58] Annona squamosa Philippines [7] Justicia adhatoda Indonesia [7] Solanum melongena Laos [7] Fibroidium abelmoschi (syn. Oidium
abelmoschi)Hibiscus ficulneus, Hibiscus sabdariffa Myanmar [13] Fibroidium balsaminae (syn, Oidium balsaminae) Impatiens balsamina Myanmar [13] Fibroidium heliotropii-indici (syn. Oidium heliotropii-indici) Heliotropium indicum, Heliotropium ovalifolium, Heliotropium supinum Myanmar [13] Heliotropium indicum Indonesia, Philippines [2,8] Fibroidium tingitaninum (syn. Oidium tingitaninum) Citrus aurantium, Citrus nobilis var. deliciosa, Citrus sinensis Indonesia [7] Citrus mitis, Citrus nobilis var. deliciosa Philippines [7] Golovinomyces ambrosiae Helianthus annuus Thailand [59] Golovinomyces biocellatus Momordica charantia Thailand [36] Golovinomyces biocellatus (syn. Oidium erysiphoides) Cucurbita moschata, Lagenaria siceraria, Luffa acutangula, Momordica charantia Thailand [30] Cajanus cajan Myanmar [37] Golovinomyces bolayi Vigna umbellata Thailand [60] Golovinomyces cichoracearum Cucurbita ovifera Myanmar [13] Dahlia sp. Thailand [61] Mangifera indica Indonesia [7] Zinnia sp. Philippines [62] Golovinomyces cichoracearum (syn. Erysiphe cichoracearum) Capsicum annum; Capsicum frutescens, Cucurbita maxima Philippines [40] Cucumis melo, Cucumis melo var. cantalupensis Philippines [31,63,64] Vigna radiata, Phaseolus aureus, Phaseolus radiatus Philippines [31,39−42] Solanum lycopersicum Philippines [65] Cucumis sativus, , Cucurbita moschata, Nicotiana tabacum Citrullus lunatus Philippines [31] Citrullus lunatus, Citrullus vulgaris, Cucurbita pepo Philippines [63,64,66] Lagenaria leucantha, Lagenaria siceraria; Benincasa hispida Philippines [64] Chrysanthemum coronarium, Chrysanthemum morifolium Philippines [67] Golovinomyces cynoglossi Myosotis scopioides Thailand [59] Golovinomyces lycopersici (syn. Oidium lycopersici) Solanum lycopersicum Myanmar [13] Golovinomyces ocimi (syn. Oidium ocimi) Ocimum gratissimum Myanmar [13] Ocimum tenuiflorum Thailand [59] Golovinomyces orontii Coccinia indica, Coccinia grandis Vigna umbellate Thailand [59] Golovinomyces spadiceus Dahlia x hortenisis Dahlia pinnata, Laggera crispata, Verbena × hybrida Thailand [59] Golovinomyces sonchicola Sonchus oleraceus Thailand [59] Golovinomyces sordidus Plantago major Vietnam [68] Golovinomyces tabaci Cucumis sativus Myanmar [13] Coccinia grandis Thailand [60] Golovinomyces sp. Ageratum conyzoides, Bidens pilosa, Lactuca indica, Lygisma inflexum Thailand [59] Leveillula clavata Euphorbia pulcherrima Indonesia [2] Leveillula taurica Oxalis barrelieri Singapore [7] Euphorbia pulcherrima, Tropaeolum majus, Capsicum frutescens Indonesia [7] Capsicum annuum var. longum Malaysia [7] Capsicum annuum Malaysia [69] Brunei Darussalam [70] Thailand [7] Myanmar [13] Tropaeolum majus Myanmar [7,13] Solanum melongena Myanmar [7,13] Solanum lycopersicum Myanmar [13] Philippines [31,63,64] Solanum aculeatissimum, Solanum torvum, Euphorbia heterophylla Thailand [71] Euphorbia geniculata Thailand [7] Hibiscus sabdariffa Thailand [7,30] Leveillula taurica (syn. Oidiopsis sicula) Capsicum frutescens, C. annuum var. grossum, C. frutescens × C. chinense (Bhut Jolokia), Capsicum sp. Thailand [72] Leveillula sp. Glycine max, Lagerstroemia speciosa Thailand [7] Microidium agatidis (syn. Oidium agatidis) Sesbania grandiflora Vietnam [2] Agati grandiflora Vietnam [8] Microidium phyllanthi Phyllanthus urinaria Vietnam [73] Microidium phyllanthi (syn. Oidium phyllanthi) Phyllanthus acidus, Phyllanthus amarus, Phyllanthus reticulatus Vietnam [74,75] Phyllanthus nanus Myanmar [13] Phyllanthus sp. Brunei Darussalam [34] Microidium phyllanthi-reticulati Phyllanthus reticulatus Thailand [76] Oidiopsis sp. Capsicum sp., Solanum lycopersicum Thailand [30] Chrozophora plicata Myanmar [13] Oidium arachidis Arachis hypogaea Indonesia [7] Oidium caricae-papayae Carica papaya Myanmar [13] Brunei Darussalam [34] Oidium euphorbiae-hirtae Euphorbia pilulifera Indonesia [7] Oidium heveae Hevea collina, Hevea guianensis, Hevea spruceana Indonesia [7,77] Hevea brasiliensis Brunei Darussalam [7,70] Cambodia [7,35] Indonesia [77] Malaysia [69, 77−80] Myanmar [7,13] Thailand [7,30,78] Vietnam [7] Oidium indigoferae Indigofera hirsuta Singapore [8] Oidium nephelii Durio zibethinus Indonesia [47,52] Thailand [30,46] Nephelium lappaceum Brunei Darussalam [7,70] Indonesia [2,81] Malaysia [80] Singapore [7] Thailand [30,46] Oidium oxalidis Oxalis corniculata Philippines, Indonesia [7] Oxalis repens Philippines [82] Oidium papaveracearum Argemone mexicana Myanmar [13] Oidium sp. Brassica chinensis, Coccinia grandis, Cosmos caudatus, Durio zibethinus, Lagenaria leucantha, Litchi chinensis, Luffa acutangula, Momordica charantia, Sesbania grandiflora, Thailand [7] Coccinia indica, Cucumis melo var. cantalupensis, Dahlia rosea, Heliotropium indicum, Impatiens balsamina, Pedilanthus tithymaloides, Phaseolus aureus, Pisum sativum, Rosa sp., Sesamum indicum, Triticum vulgare, Vigna sesquipedalis, Zinnia elegans, Ziziphus jujube, Ziziphus mauritiana Thailand [30] Cassia sp. Thailand [37] Antigonon leptopus, Cucurbita pepo var. medullosa, Impatiens balsamina, Luffa aegyptiaca, Rosa sp., Brunei Darussalam [7] Cucumis melo, Cucumis sativus, Cucurbita maxima, Cucurbita pepo, Dahlia sp., Hibiscus mutabilis, Luffa acutangula, Luffa cylindrical, Vigna sesquipedalis, Zinnia elegans, Brunei Darussalam [7,70] Helianthus annuus, Euphorbia tithymaloides, Acacia sp., Brunei Darussalam [34] Baliospermum axillare, Bougainvillea spectabilis, Coccinia indica, Codiaeum variegatum, Eclipta alba, Helianthus annuus, Lagerstroemia indica, Psoralea corylifolia, Sechium edule, Sesamum indicum, Tephrosia purpurea, Tinospora cordifolia, Myanmar [13] Cajanus cajan, Croton calococcus, Cucumis sativus, Cucurbita sp., Glochidion sp., Lagenaria leucantha, Phaseolus aureus, Piper betle, Pisum sativum, Vigna unguiculata Myanmar [7] Capsicum frutescens, Citrus reticulate, Corchorus capsularis, Cucurbita pepo, Sesamum indicum , Vigna sesquipedalis, Vitis vinifera, Zinnia elegans Cambodia [35] Corchorus olitorius, Cucumis sativus Cambodia [7] Acacia sp. Indonesia [53] Albizia falcate, Albizia moluccana, Angelonia salicariifolia Blumea balsamifera, Boehmeria nivea, Capsicum annuum var. grossum, Capsicum frutescens, Cassia multijuga, Cassia occidentalis, Cassia surattensis, Cassia tora, Celtis tetrandra, Citrus hystrix f. acida, Clitoria ternatea, Crotalaria juncea, Cucumis sativus, Cucurbita maxima, Cucurbita pepo, Cucurbita sp., Deguelia microphylla, Desmodium gyroides, Elatostema sessile, Eugenia densiflora, Heliotropium indicum, Indigofera sumatrana, Justicia adhatoda, Lagerstroemia sp., Luffa aegyptiaca, Manihot glaziovii, Mirabilis jalapa, Morus alba, Myristica fragrans, Phaseolus vulgaris, Phyllanthus niruri, Physalis minima, Rosa sp., Sida acuta, Tamarindus indica, Torenia asiatica, Verbena laciniata Indonesia [7] Cucurbita sp., Solanum melongena Laos [7] Antigonon leptopus Malaysia [70] Angelonia salicariifolia, Benincasa cerifera, Cassia occidentalis, Cassia tora, Cucumis sp., Cucurbita moschata, Heliotropium indicum, Hydrangea sp., Impatiens balsamina, Luffa acutangula, Solanum lycopersicum, Physalis minima, Psophocarpus tetragonolobus, Tamarindus indica, Vigna sinensis Malaysia [69] Corchorus capsularis, Euphorbia hirta, Hibiscus mutabilis Malaysia [83] Benincasa hispida, Corchorus olitorius, Indigofera hirsute, Nephelium mutabile, Solanum melongena, Stachytarpheta indica, Vigna sesquipedalis Malaysia [7] Cucumis sativus, Cucurbita maxima, Cucurbita pepo, Phaseolus vulgaris, Sesamum indicum Malaysia [69,] Sauropus androgynous, Vitis vinifera, Zinnia elegans Malaysia [84] Senna occidentalis, Senna tora Malaysia [37] Capsicum annuum, Cucurbita maxima, Desmodium procumbens, Heliotropium indicum, Oxalis repens, Phaseolus sp., Pisum sativum, Philippines [7] Samanea saman Philippines [85] Stachytarpheta indica, Peltophorum pterocarpum Singapore [7] Cucumis melo, Hevea sp., Nicotiana tabacum, Prunus persica, Prunus triflora, Prunus triloba, Sesbania grandiflora Vietnam [7] Acacia auriculiformis Thailand, Malaysia [53] Philippines [86] Acacia mangium Thailand, Malaysia, Philippines [85] Nicotiana tabacum Thailand, Cambodia, Indonesia, Vietnam [7] Malaysia [69] Myanmar [13] Ovulariopsis moricola Morus alba Thailand [30] Phyllactinia alangii Alangium kurzii Thailand [71] Phyllactinia broussonetiae-papyriferae Broussonetia papyrifera Thailand [71] Phyllactinia cassiae-fistulae Cassia fistula Thailand [87] Phyllactinia dalbergiae Dalbergia lanceolaria Thailand [71] Phyllactinia gmelinae Gmelina arborea Thailand [71] Phyllactinia guttata (syn. Phyllactinia corylea) Morus alba Thailand [30] Morus sp. Myanmar [13] Indonesia [77] Phyllactinia guttata (syn. Phyllactinia suffulta) Morus alba Philippines [31,40,55] Phyllactinia lagerstroemiae Lagerstroemia macrocarpa, Lagerstroemia speciosa Thailand [88] Phyllactinia mori-macrourae Morus macroura Thailand [71] Phyllactinia moricola Morus sp. Myanmar; Vietnam [7,13] Morus alba Thailand [71] Morus rubra Thailand [71] Phyllactinia poinsettiae Euphorbia pulcherrima Indonesia [12] Phyllactinia pyri-communis Pyrus communis Myanmar [13] Phyllactinia terminaliae Terminalia bellirica Thailand [71] Phyllactinia sp. Ehretia laevis Thailand [71] Rosa sp. Philippines [89] Podosphaera aphanis Fragaria ×ananassa Thailand [36] Podosphaera caricicola Carica papaya Thailand [21] Podosphaera euphorbiae-hirtae Euphorbia hirta Myanmar [13] Podosphaera fuliginea (syn. Sphaerotheca fuliginea) Phaseolus aconitifolius Myanmar [7] Cucurbita moschata, Impatiens balsamina, Luffa aegyptiaca Malaysia [7] Benincasa hispida, Cucurbita moschata, Dahlia variabilis, Impatiens balsamina Singapore [7] Podosphaera fusca Bidens sp. Malaysia, Singapore [36] Cosmos caudatus Malaysia [90] Zinnia elegans Thailand [61] Podosphaera fusca (syn. Sphaerotheca fusca) Carica papaya Brunei Darussalam [34] Podosphaera pannosa (syn. Sphaerotheca pannosa) Rosa sp. Brunei Darussalam [70] Myanmar [13] Thailand [30] Rosa hybrida Thailand [36] Rosa sp. Philippines [91] Podosphaera perseae-americanae Persea americana Indonesia [92] Podosphaera pruni-cerasoidis Prunus cerasoides Thailand [93] Podosphaera xanthii (syn. Podosphaera
caricae-papayae)Carica papaya Thailand [45] Podosphaera xanthii Cajanus cajan, Cucurbita maxima, Cucurbita ovifera,
Cucurbita pepo, Lagenaria vulgaris, Luffa aegyptiaca, Phaseolus aconitifolius, Phaseolus mungo, Pisum sativum, Sesamum indicum,
Vicia unguiculata, Vigna catjangMyanmar [13] Vigna unguiculata subsp. sesquipedalis, Vigna radiata, Solanum melongena Philippines [94,95] Ageratum conyzoides Thailand [61] Cucumis melo Thailand [96] Bidens pilosa, Carica papaya, Chamaesyce hirta, Cleome rutidosperma, Cosmos sulphureus, Crotalaria pallida, Cucumis sativus, Cucurbita pepo, Cyanthillium cinereum, Dahlia pinnata, Euphorbia hirta, Euphorbia tithymaloides, Galinsoga parviflora, Gymnema inodorum, Heliotropium indicum, Impatiens balsamina, Justicia comata, Macroptilium atropurpureum, Millingtonia hortensis, Momordica charantia, Phaseolus vulgaris, Physalis angulate, Pouzolzia zeylanica, Senna occidentalis, Solanum melongena, Spilanthes iabadicensis, Vigna radiata, Vigna unguiculata subsp. sesquipedalis Thailand [36] Capsicum frutescens Vietnam [97] Jatropha gossypiifolia Vietnam [98] Podosphaera sp. Aster sp., Cleome viscosa, Coccinia grandis, Cucurbita moschata, Helianthus annuus, Hibiscus mutabilis, Hibiscus sabdariffa, Hydrocleys nymphoides, Kydia sp., Lagenaria siceraria var. gourda, Leucas decemdentata, Prunus mume, Prunus persica, Raphistemma pulchellum, Sesamum indicum, Viola tricolor, Zinnia elegans Thailand [36] Pseudoidium antigononis (syn. Oidium antigononis) Antigonon leptopus Brunei Darussalam [2] Pseudoidium azadirachtae (syn. Oidium azadirachtae) Azadirachta indica Myanmar [13] Pseudoidium clitoriae (syn. Oidium clitoriae) Clitoria ternatea Cambodia, Indonesia [2,8] Pseudoidium fabacearum Sesbania grandiflora Thailand, Vietnam [2] Pseudoidium hortensiae (syn. Oidium hortensiae) Hydrangea sp. Indonesia [7] Thailand [61] Hydrangea macrophylla Thailand [19] Pseudoidium ipomoeae (syn. Oidium
ipomoeae)Ipomoea aquatic, Ipomoea obscura Thailand [23] Ipomoea reniformis Myanmar [13] Pseudoidium javanicum Acalphya argentea, Acalypha wilkesiana Indonesia [25] Pseudoidium leptadeniae (syn. Oidium leptadeniae) Leptadenia reticulata Myanmar [13] Pseudoidium moluccanum (syn. Oidium moluccanum) Aleurites moluccana Timor-Leste [2,99] Pseudoidium neolycopersici Physalis sp. Thailand [20] Pseudoidium peltophori (syn. Oidium
peltophori)Peltophorum pterocarpum Singapore [2,8] Pseudoidium schmiedeknechtii (syn. Oidium schmiedeknechtii) Hibiscus floccosus, Schoutenia glomerata, Urena lobata Thailand [20] Pseudoidium stachytarphetae (syn. Oidium stachytarphetae) Stachytarpheta indica Singapore [2,8,100] Pseudoidium tamarindi (syn. Oidium
tamarindi)Tamarindus indica Indonesia, Singapore [2,8] Myanmar [13] Pseudoidium urenae (syn. Oidium urenae) Urena lobata Myanmar [13] Powdery mildew has been reported to host up to 9,838 plant species worldwide, all of which are angiosperms (flowering plants), including several economically important plants, and not gymnosperms, ferns (pteridophytes)[7] or lower plants such as mosses and liverworts (bryophytes)[11]. Thus, powdery mildew is considered one of the most important plant pathogens. Economically significant hosts in SEA includes vegetables, fruits, vines, herbs, field crops, ornamentals, and tree species. Most genera and species of powdery mildew disease are explicit to plants of a single genus. An example of this is Blumeria infecting only grasses (Poaceae). Thus far in SEA, Thailand has the most recorded powdery mildew hosts in a generally tropical, warm, and humid climate and practices intensive agriculture, which makes them favorable for the proliferation of powdery mildew conidia. However, most of the host plants in the SEA are herbaceous species. This difference undoubtedly reflects the growth habit of the powdery mildew fungus, which is limited mainly to leaves and succulent shoots and stems.
Southeast Asian countries have a relatively low level of exploration, perhaps due to the limited number of experts or mycologists studying powdery mildews relative to Eastern Asia, Europe, and the rest of the world. Moreover, surveys and reports of powdery mildew in Southeast Asia have been sparse in recent years, which should contribute to and be updated to understand this ubiquitous plant pathogen better. Also, in subtropics and tropics, the powdery mildew's sexual reproductive stage (teleomorph), essential for accurate species identification, is largely absent[12].
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Diseases constitute a significant factor in diminishing yield and productivity in Southeast Asia, as they do elsewhere. Compared to other fungal diseases, powdery mildew causes less debilitating losses due to the lack of systemic and root infections and minimal host death[101]. However, with the impact of climate change — the increased CO2 emissions and rising temperatures in Southeast Asia (Myanmar, Philippines, Vietnam, and Thailand being among the most affected in the world by climate change[102], powdery mildew disease may continuously aggravate in the future[103−108] through increased colony establishment[109] and effect in plant host’s physiology and susceptible openings such as stomata[110], resulting in a higher risk of infection. Powdery mildew disease may cause a disease outbreak which brings plant growth reduction, premature defoliation, and reduction in fruit quality and yield, especially of economically important crops resulting in significant economic loss if not managed in the early stages since fungal growth covers entire photosynthetic green areas of the plant hindering food manufacturing mechanism of host plants[101].
Some recorded powdery mildew impacts in SEA are from legumes and important tree species. Yield reduction of 21%[111] up to 58%[112] in the Philippines, 50% in Thailand[113], and 20%–40% in Southeast Asia[41,114,115] have been recorded in mungbean that can lead to complete plant loss during seedling or early plant stage[116]. A decline in soybean seed quantity, weight, physical quality, and germination of 50%–52%[117] and a yield reduction of 10%–90% was recorded in Indonesia[118]. In Indonesia, powdery mildew disease of rubber trees also posted a reduction in rubber latex yields by up to 45%, including damage to young rubber leaves, buds, inflorescences, and other immature tissues[119,120]. Powdery mildew infection of 90%–100% of Acacia auriculiformis seedlings was recorded in Thailand, where about 75% of the seedlings were wiped out[121]. Known tree hosts of powdery mildew may overcome the disease as it matures, as observed on > 2-year-old trees[122].
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Host plant resistance has been widely used in crop breeding to develop powdery mildew disease-resistant cultivars for avoiding or minimizing yield losses due to disease infestation. Some sources of resistance against powdery mildew have been identified in SEA (Table 2). The resistant genotypes listed range from highly resistant (HR) to moderately resistant (MR). These sources can be incorporated through conventional and biotechnological approaches to breeding powdery mildew-resistant cultivars.
Table 2. Some sources of powdery mildew resistance in Southeast Asia.
Powdery mildew
speciesCrop Country Resistant genotypes References Erysiphe diffusa (syn. Microsphaera diffusa) Soybean Vietnam HR- SV1, SV2, SV3, SV4, SV14, SV17
R- SV7, SV11, SV12, SV13, SV24, SV26, SV27, SV28, SV29, SV33[125] Indonesia HR- UP-104, UP-106, UP-108, UP-111, UP-112, UP-113, UP-114,
UP-125, UP-127, UP-130, UP-136, UP-137, Argomulyo, Arjasari, Mintani[118] Erysiphe polygoni Mungbean Philippines HR- CES ID-21 (Pag-asa) [111] Thailand HR- VC 6468
R- Kamphaeng Saen 2[124] HR- VC1973A and VC2778A
HR- VC1210A
R- VC1482A, VC2273, VC3528A[126,127] R- M5-10 and M5-25 [128] R- V4718 and RUM5 [129] MR- VC 2764 Y, VC 1163, VC 2768, VC 3876 [129] Erysiphe sp. Melon Myanmar HR- I-7, I-10, I-18, I-19, B-1
R- I-4, I-11, I-12, I-21, I-22 I-23, N-1[130] Oidium sp. Mungbean Thailand MR- Chai Nat 36, Kamphaeng Saen 1, Kamphaeng Saen 2 [131] Phyllactinia guttata Mulberry Vietnam HR- EC-493900 Vietnam-2 [132] Indonesia MR- M. multicaulis (M), EC-493895 M. multicaulis (B) Myanmar EC-493973 M. rotundiloba Thailand EC-49352 Thailand Lobed Podosphaera xanthii Eggplant Philippines HR- PPLEgpAcc042 and PPLEgpAcc049 [95] Bittergourd Myanmar, Philippines, Thailand, Vietnam R- THMC 113, THMC143, THMC153, THMC167, THMC 170 [133] Vietnam R- THMC 60-1, THMC 354 [134] Philippines R- THMC 28-2-2, THMC 30, THMC 31, THMC 33, THMC 35, THMC 37, THMC 42, THMC 43, THMC 44 [134] HR - Highly resistant; R - Resistant; MR - Moderately resistant. Though these genotypes are reported to have powdery mildew resistance (high to moderate), races or shifts in virulence of the population occur since some of the resistance reported from the past years weakened or were not resistant anymore. Besides the possibility of race, other factors like inoculum density and environments can also influence the resistance or susceptibility of plant genotypes to powdery mildew[123]. Nevertheless, a more stable resistance may be established using a combination of quantitative and major genes in resistance breeding. The former serves as a buffer to the resistant culivar, therefore supporting extending the lifespan of a resistant cultivar[124].
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Many plant species in Southeast Asia are affected by powdery mildew dispersed to and from different parts of the world. It threatens various economically important vegetables, fruits, vines, herbs, field crops, ornamentals, and tree species in Southeast Asia and worldwide. A comprehensive survey of powdery mildews in these localities may be warranted to verify and update the existing genera and species and their hosts in Southeast Asia and clarify the biodiversity and evolution of this important plant pathogenic fungal group. It is also crucial to study the effects of climate change on the powdery mildew disease-host plant pathosystem, which may contribute to the exacerbation of the disease. Climate changes could alter virulence under cultivation and in natural habitats. Hence understanding how these abiotic factors and their interactions affect virulence has vital implications. It is also imperative to formulate cost-effective integrated disease management, i.e., cultural, chemical, biological, and host resistance to powdery mildew management strategies at each level, considering prevailing environmental conditions under several plant species.
Moreover, sources of powdery mildew resistance listed in Southeast Asia should also be described appropriately whether resistance in these genotypes is race-specific, based on a form of slow mildewing resistance, or non-host resistance, because studies show that race-nonspecific resistance to powdery mildew provides more durable disease resistance[135]. Furthermore, the mechanism of non-host resistance against powdery mildew of various plant species should also be exploited, which is considered more durable and robust resistance[101].
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The authors declare that they have no conflict of interest.
- Copyright: © 2023 by the author(s). Published by Maximum Academic Press, Fayetteville, GA. This article is an open access article distributed under Creative Commons Attribution License (CC BY 4.0), visit https://creativecommons.org/licenses/by/4.0/.
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Cite this article
Aumentado HDR, Guerrero JJG, Balendres MAO. 2023. Powdery mildew in Southeast Asia: host range, impact, and sources of resistance. Technology in Agronomy 3:9 doi: 10.48130/TIA-2023-0009 
Powdery mildew in Southeast Asia: host range, impact, and sources of resistance
- Received Date: 20 May 2023
- Accepted Date: 28 June 2023
- Published Online: 18 August 2023
Abstract: Powdery mildews are important obligate biotrophic ectoparasites that cause severe damage to various plant species in Southeast Asia. So far, 14 genera and 96 species of powdery mildew have been reported in Southeast Asia, with Thailand having the most number of recorded species. Of the 14 genera reported, Oidium sp. had the most recorded host, including several important species of vegetables, fruits, vines, herbs, field crops, ornamentals, and tree species. This paper briefly reviews the knowledge of powdery mildew disease in Southeast Asia, focusing on the pathogens' host range, impact, and some sources of resistance to powdery mildew.
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Key words:
- Erysiphales /
- Oidium species /
- Angiosperms /
- Fungal plant pathogens