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
Syngenta Crop Protection AG
Capsicum annuum L. · Bell pepper
HM.Clause S.A.S.
Cucumis sativus L. · Cucumber
Rijk Zwaan Zaadteelt en Zaadhandel B.V.
Cucumis melo L. · Melon
SEMILLAS FITO, S.A.
Cucumis sativus L. · Cucumber
Rijk Zwaan Zaadteelt en Zaadhandel BV (NL)
Solanum lycopersicum L. · Tomato
Vilmorin-Mikado S.A.S.
Cucumis melo L. · Melon
Graines Gautier SA (FR)
Cucumis sativus L. · Cucumber
HAZERA SEEDS BV
Cucumis melo L. · Melon
De Ruiter Zonen (HR)
Avena strigosa Schreb. · Black oat
P.H. Petersen Saatzucht Lundsgaard GmbH Herrn Asmus Sören Petersen / Michaela Schlathölter
Capsicum annuum L. · Bell pepper
HM.Clause S.A.S.
Lactuca sativa L. · Lettuce
Gautier Semences SAS (FR)
Cucumis sativus L. · Cucumber
Enza Zaden Beheer B.V.
Malus domestica (Suckow) Borkh. · Apple
Domaine Public (FR)
Phlox paniculata L. · Garden phlox
Bartels, G.B.H.
Cucumis sativus L. · Cucumber
ZAYIN TECHNOLOGY S.L.
Cucumis melo L. · Melon
SEMILLAS FITO, S.A.
Capsicum annuum L. · Bell pepper
Syngenta Crop Protection AG
Cucumis melo L. · Melon
Enza Zaden Beheer B.V.
Helianthus annuus L. · Sunflower
Kalinichenko Artem Oleksandrovych, Didenko Kostiantyn Oleksandrovych,
Cucumis sativus L. · Cucumber
SEMILLAS FITO, S.A.
Cucumis melo L. · Melon
Enza Zaden Beheer B.V.
Fragaria L. · Strawberry
Mattivi Breeding S.S.
Solanum lycopersicum L. · Tomato
Bayer Holland B.V.