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
Rijk Zwaan Zaadteelt en Zaadhandel B.V.
Triticum aestivum L. · Bread wheat
Lietuvos agrarinių ir miškų mokslų centras
Cucumis sativus L. · Cucumber
Rijk Zwaan Zaadteelt en Zaadhandel B.V.
x Triticosecale Wittm. ex A. Camus · Triticale
V. Georgiev, T. Petrova, I. Iliev, V. Ivanova
Cucumis sativus L. · Cucumber
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Lactuca sativa L. · Lettuce
ENZA ZADEN
Glandularia x hybrida (hort. ex Groenl. & Rümpler) G. L. Nesom & Pruski · Common Garden Verbena
Hanes Mitchell Eugene
Malus domestica (Suckow) Borkh. · Apple
Instytut Ogrodnictwa - Państwowy Instytut Badawczy
Daucus carota L. · Carrot
Cora Seeds SRL, I
Solanum lycopersicum L. · Tomato
Enza Zaden Beheer B.V.
Cucurbita pepo L. · Field pumpkin
BEJO ZADEN
Avena sativa L. · Oat
KWS MOMONT RECHERCHE SARL, FR
Cucumis sativus L. · Cucumber
BEJO ZADEN
Pisum sativum L. · Pea
Limagrain UK
x Triticosecale Wittm. ex A. Camus · Triticale
Australian Grain Technologies Pty Ltd
Cucumis sativus L. · Cucumber
Rijk Zwaan Zaadteelt en Zaadhandel B.V.
Pisum sativum L. · Pea
Limagrain UK
Pisum sativum L. · Pea
Limagrain UK
Triticum aestivum L. · Bread wheat
LIMAGRAIN EUROPE
Hordeum vulgare L. · Barley
Limagrain Europe S.A.S
Triticum aestivum L. · Bread wheat
LIMAGRAIN EUROPE
Triticum aestivum L. · Bread wheat
Limagrain Europe S.A.S
Avena sativa L. · Oat
KWS MOMONT RECHERCHE SARL, FR
Triticum aestivum L. · Bread wheat
Limagrain Europe S.A.S