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.
Trifolium pratense L. · Red clover
INTERNATIONAL SEEDS INC
Cucumis sativus L. · Cucumber
Nickerson Zwaan
Ribes uva-crispa L. · Gooseberry
Werner Grafmüller
Cucumis sativus L. · Cucumber
PRIDNESTROVSKIJ NIISX
Phaseolus coccineus L. · Runner bean
A L TOZER LTD
Triticum aestivum L. · Bread wheat
RAGT 2N S.A.S
Brassica napus var. napus · Rapeseed
New Zealand Institute for Crop and Food Research Ltd
Triticum aestivum L. · Bread wheat
RAGT 2N S.A.S
x Triticosecale Wittm. ex A. Camus · Triticale
RAGT 2N S.A.S
Cucurbita pepo L. · Field pumpkin
Syngenta Seeds B.V.
Pisum sativum L. · Pea
APP Agroresursu un ekonomikas institūts
Avena sativa L. · Oat
RAGT 2N S.A.S
Fragaria L. · Strawberry
WASSENAR LEENDERT MICHIEL
Triticum aestivum L. · Bread wheat
RAGT 2N S.A.S
Hydrangea L. · Hydrangea
RAMPP JUNGPFLANZEN GMBH & CO. VERTRIEBS KG
Cucumis sativus L. · Cucumber
Rijk Zwaan Zaadteelt en Zaadhandel B.V.
x Triticosecale Wittm. ex A. Camus · Triticale
Institut National de Recherche pour l'Agriculture l'Alimentation et l'Environnement (INRAE) , Agri-Obtentions S.A.
Triticum aestivum L. · Bread wheat
SEMILLAS BATLLE, S.A.
Cucumis sativus L. · Cucumber
Rijk Zwaan Zaadteelt en Zaadhandel B.V.
Hydrangea macrophylla (Thunb.) Ser. · Bigleaf hydrangea
Information regarding the breeder received in the contribution to CPVO :Rampp
Beta vulgaris Garden Beet Group · Garden beet
SAKATA UK LTD
Cucumis sativus L. · Cucumber
Nunhems B.V.
Cucurbita pepo L. · Field pumpkin
Johnny's Selected Seeds
Hordeum vulgare L. · Barley
Società Produttori Sementi S.p.A.^^^Alberto Gianinetti^^^Nadia Faccini^^^Donata Pagani^^^Marina Baronchelli^^^Camillo Corvi