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.
Pisum sativum L. · Pea
PRODANA SEED A/S - DLF SEEDS A/S
Secale cereale L. · Rye
Waldemar Brukwinski, 60% Katarzyna Banaszak, 40%
Triticum aestivum L. · Bread wheat
S.A.S. Florimond Desprez Veuve & Fils
Triticum aestivum L. · Bread wheat
Pernilla Vallenback
Hordeum vulgare L. · Barley
P. Thomas Wymore
x Triticosecale Wittm. ex A. Camus · Triticale
LEMAIRE DEFFONTAINES S.A.S.
Koeleria macrantha (Ledeb.) Schult. · June grass
Barenbrug Holland BV (NL)
Festuca rubra L. · Red fescue
Barenbrug Holland BV (NL)
Triticum durum Desf. · Durum wheat
Syngenta Seed, NL
Triticum durum Desf. · Durum wheat
Serasem, FR
Lactuca sativa L. · Lettuce
Rijk Zwaan Zaadteelt en Zaadhandel B.V. (NL)
Cucumis sativus L. · Cucumber
Nunza B.V.
Daucus carota L. · Carrot
Paul Degreef
Cucumis sativus L. · Cucumber
LUIS MULLOR
Cucurbita maxima Duchesne · Giant pumpkin
TAKII EUROPE B V
Cucumis sativus L. · Cucumber
RIJK ZWAAN ZAADTEELT EN ZAADHANDEL B.V.
Cucumis sativus L. · Cucumber
RIJK ZWAAN ZAADTEELT EN ZAADHANDEL B.V.
Rosa L. · Rose
Stephens, Patrick N.|deceased, 139 Kihi Kihi Road, late of Te Awamutu, New Zealand by Patricia I. J. Stephens, legal representative, 139 Kihi Kihi Road, Te Awamutu, New Zealand
Cucumis melo L. · Melon
RIJK ZWAAN ZAADTEELT EN ZAADHANDEL B.V.
Cucumis sativus L. · Cucumber
Nunhems B.V., 6083 AB Nunhem
Cucumis sativus L. · Cucumber
Nunhems, NL
Daucus carota L. · Carrot
Vilmorin SA (FR)
Triticum aestivum L. · Bread wheat
Stacja Hodowli Roślin MODZURÓW Grupa Szelejewo sp. z o.o.
Cucumis sativus L. · Cucumber
VEGETABLE MONSANTO B.V.