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.
Capsicum annuum L. · Bell pepper
Rijk Zwaan Zaadteelt en Zaadhandel B.V.
Cucumis melo L. · Melon
Syngenta Seeds BV (NL)
Cucumis sativus L. · Cucumber
Rijk Zwaan Zaadteelt en Zaadhandel BV (NL)
Cucumis sativus L. · Cucumber
Rijk Zwaan Zaadteelt en Zaadhandel B.V.
Cucumis sativus L. · Cucumber
Rijk Zwaan Zaadteelt en Zaadhandel B.V.
Cucurbita pepo L. · Field pumpkin
SEMILLAS FITO, S.A.
Vitis L. · Grapevine
REINHARD ToPFER / RUDOLF EIBACH
Prunus persica (L.) Batsch · Peach
Laurence Maillard, Arsene Maillard
Cucurbita pepo L. · Field pumpkin
United Genetics, I
Cucumis sativus L. · Cucumber
Rijk Zwaan Zaadteelt en Zaadhandel B.V.
Cucumis sativus L. · Cucumber
Rijk Zwaan Zaadteelt en Zaadhandel B.V.
Capsicum annuum L. · Bell pepper
Rijk Zwaan Zaadteelt en Zaadhandel B.V.
Cucumis sativus L. · Cucumber
SEMO A.S., CZ
Beta vulgaris Sugar Beet Group · Sugar beet
Betaseed
Beta vulgaris Sugar Beet Group · Sugar beet
KWS SAAT SE & CO.KGAA
x Triticosecale Wittm. ex A. Camus · Triticale
Saaten Union Recherche (FR)
Beta vulgaris Sugar Beet Group · Sugar beet
Betaseed
Cucumis sativus L. · Cucumber
Rijk Zwaan Zaadteelt en Zaadhandel B.V.
Cucumis sativus L. · Cucumber
Rijk Zwaan Zaadteelt en Zaadhandel B.V.
Cucumis sativus L. · Cucumber
Rijk Zwaan Zaadteelt en Zaadhandel B.V.
Triticum durum Desf. · Durum wheat
SEMILLAS BATLLE, S.A.
Cucurbita pepo L. · Field pumpkin
Syngenta Seeds B.V.
Triticum aestivum L. · Bread wheat
I. Panayotov, G. Petrov, I. Todorov, P. Petkova, D. Boyadzhieva, A. Dimov, P. Stankova, V. Vasilev, P. Stoycheva
Secale cereale L. · Rye
Franz Haag