Diseases
Erysiphales
Powdery mildew is a fungal disease manifesting as a white web-like coating on plant organs, leading to tissue necrosis, fruit deformation, and significant crop losses.
Mentioned in descriptions 33 570 varieties reference book.
Powdery mildew is caused by ectoparasitic fungi of the order Erysiphales, which develop primarily on the surface of leaves, shoots, and fruits. The initial white web-like coating eventually densifies into "powdery" cushions, upon which fungal fruiting bodies may form as dark spots. As a result of the infection, tissues turn yellow and become necrotic, fruits may crack, and leaves drop prematurely.
The intensity of disease development depends on a complex of factors: high relative humidity, moderate temperatures, the presence of dense canopy, and excessive nitrogen nutrition. Risks increase with alternating dry and wet weather. The harmfulness of the disease is expressed in a reduction of the leaf assimilation area, deterioration of crop quality, and a decrease in the general winter hardiness of crops.
Assessment of variety resistance is conducted under field conditions at various stages of vegetation, most often during the full heading phase. To classify the degree of infection, scoring systems or intensity scales in percentages are used, where varieties with up to 10% infection are considered highly resistant (R), 11 to 40% as moderately resistant (M), and more than 41% as susceptible (S). Variety resistance is ensured by genetic mechanisms that prevent colonization by the pathogen or limit the development of its mycelium.
Selection based on the description text, not official resistance ratings: such data is not available in registers. Mention indicates that the trait is discussed in the variety's sources; see the variety's profile for details on what is specifically stated.
Lactuca sativa L. · Lettuce
Rijk Zwaan Zaadteelt en Zaadhandel B.V.
Cucumis sativus L. · Cucumber
VEGETABLE MONSANTO B.V.
Cucurbita pepo L. · Field pumpkin
Syngenta Seeds B.V.
Trifolium pratense L. · Red clover
Latvijas Lauksaimniecibas universitate
Vitis L. · Grapevine
Valentin Blattner
Cucumis melo L. · Melon
Nunhems B.V.
Triticum aestivum L. · Bread wheat
Sejet Planteforaedling I,S
Cucurbita pepo L. · Field pumpkin
HM.Clause S.A.S.
Lactuca sativa L. · Lettuce
Rijk Zwaan Zaadteelt en Zaadhandel B.V.
Cucumis sativus L. · Cucumber
Selekcijos ir sėklininkystės firma ,,Manul"
Cucumis sativus L. · Cucumber
Nunhems B.V.
Hordeum vulgare L. · Barley
Lietuvos agrarinių ir miškų mokslų centras
Triticum aestivum L. · Bread wheat
F.LLI COZZI S.N.C.
hybrids between Solanum lycopersicum L. and S. habrochaites S. Knapp & D.M. Spooner
Enza Zaden Beheer B.V.
Triticum aestivum L. · Bread wheat
SEMILLAS BATLLE S.A.
Malus domestica (Suckow) Borkh. · Apple
Institut National de Recherche pour l'Agriculture l'Alimentation et l'Environnement (INRAE) , Institut Français des Productions Cidricoles (I.F.P.C.)
Triticum durum Desf. · Durum wheat
Stephanie Franck
Cucumis sativus L. · Cucumber
Rijk Zwaan Zaadteelt en Zaadhandel B.V.
Cucurbita pepo L. · Field pumpkin
TOZER SEEDS LTD
Hordeum vulgare L. · Barley
Hodowla Roslin Smolice Sp.z o.o Grupa IHAR
Cucumis sativus L. · Cucumber
SYNGENTA SEEDS B.V , NL
Cucumis melo L. · Melon
HAZERA SEEDS BV
Secale cereale L. · Rye
Hodowla Roslin Smolice Sp.z o.o Grupa IHAR
Cucumis sativus L. · Cucumber
Enza Zaden, NL