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.
Cucumis sativus L. · Cucumber
Graines Voltz (FR)
Hordeum vulgare L. · Barley
Syngenta UK Ltd
Prunus persica (L.) Batsch · Peach
Triticum aestivum L. · Bread wheat
INSTITUT NATIONAL DE LA RECHERCHE AGRONOMIQUE, FR
Fragaria L. · Strawberry
Simpson, D. W.
Avena sativa L. · Oat
Danko Hodowla Roslin Sp.z.o.o.
Allium cepa L. var. cepa · Onion
Seminis Vegetable Seeds
Festuca arundinacea Schreb. · Tall fescue
DLF-Trifolium (DK)
Solanum lycopersicum L. · Tomato
Rijk Zwaan Zaadteelt en Zaadhandel B.V.
Solanum lycopersicum L. · Tomato
Rijk Zwaan Zaadteelt en Zaadhandel B.V.
Citrullus lanatus (Thunb.) Matsum. & Nakai · Watermelon
HAZERA SEEDS BV
Beta vulgaris Sugar Beet Group · Sugar beet
SAS FLORIMOND-DESPREZ Veuve et Fils
Fragaria x ananassa Duchesne ex Rozier · Garden strawberry
Saatzucht Bauer Gmbh (DE)/Birgid SCHLINDWEIN (DE)
Beta vulgaris Sugar Beet Group · Sugar beet
Danisco Seed A/S (Danisco Sugar A/S)
Petroselinum crispum (Mill.) Nyman ex A. W. Hill · Parsley
Rijk Zwaan B.V. (NL)
Cucumis sativus L. · Cucumber
SAKATA VEGETABLES EUROPE SAS
Cucumis melo L. · Melon
NUNHEMS BIO OBTENTION
Triticum aestivum L. · Bread wheat
Agri-Obtentions S.A., Institut National de Recherche pour l'Agriculture l'Alimentation et l'Environnement (INRAE)
Cucumis melo L. · Melon
Syngenta Seeds B.V.
Cucumis melo L. · Melon
Syngenta Crop Protection AG
Petroselinum crispum (Mill.) Nym. ex A.W. Hill ssp. crispum · Parsley
Rijk Zwaan B.V.
Beta vulgaris Sugar Beet Group · Sugar beet
Florimond Desprez Veuve et Fils, FR
Cucumis melo L. · Melon
Ralf Kuijpers
Citrullus lanatus (Thunb.) Matsum. & Nakai · Watermelon
Rijk Zwaan Zaadteelt en Zaadhandel B.V.