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.
Fragaria x ananassa Duchesne ex Rozier · Garden strawberry
Zenti Franco
Cucumis sativus L. · Cucumber
Syngenta Crop Protection AG
Capsicum annuum L. · Bell pepper
Enza Zaden Beheer B.V.
Rosa L. · Rose
ALAIN ANTOINE MEILLAND (FR)
Beta vulgaris Sugar Beet Group · Sugar beet
DLF Beet Seed APS
Rosa L. · Rose
ALAIN ANTOINE MEILLAND (FR)
Rosa L. · Rose
MEILLAND ALAIN| Alain Meilland
Cucurbita pepo L. · Field pumpkin
Gautier Semences SAS (FR)
Daucus carota L. · Carrot
Vilmorin & Cie
Lactuca sativa L. · Lettuce
Clause (FR)
Rosa L. · Rose
ALAIN ANTOINE MEILLAND (FR)
Brassica oleracea L. (White Cabbage Group) · White cabbage
Instytut Ogrodnictwa - Państwowy Instytut Badawczy
Fragaria x ananassa Duchesne ex Rozier · Garden strawberry
Marian Lisowski
Cucumis melo L. · Melon
Clause Semences SA (FR)
Solanum lycopersicum L. · Tomato
UNITED GENETICS SEEDS CO
Avena sativa L. · Oat
Plant Breeding International Cambridge Ltd (GB)
Hordeum vulgare L. · Barley
Plant Breeding International Cambridge Ltd (GB)
Cucumis sativus L. · Cucumber
Rijk Zwaan Zaadteelt en Zaadhandel B.V.
Solanum lycopersicum L. · Tomato
Gautier Semences SAS (FR)
Cucurbita pepo L. · Field pumpkin
Gautier Semences SAS (FR)
Solanum lycopersicum L. · Tomato
Gautier Semences SAS (FR)
Cucumis melo L. · Melon
UNITED GENETICS SEEDS CO
Hordeum vulgare L. · Barley
P.BREED.INT.CAMBRIDGE
Brassica rapa L. var. rapa (L.) Thell. · Turnip
James Hutton Institute