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.
Hordeum vulgare L. · Barley
Lantmännen SW Seed
Cucumis sativus L. · Cucumber
Rijk Zwaan Zaadteelt en Zaadhandel B.V.
Cucurbita pepo L. · Field pumpkin
Shevchenko Igor
Cucumis sativus L. · Cucumber
MORAVOSEED
Solanum lycopersicum L. · Tomato
Kees Konst
Cucumis sativus L. · Cucumber
Domaine Public (FR)
Cucurbita pepo L. · Field pumpkin
Tezier SA (FR)
Cucumis sativus L. · Cucumber
ZERAIM GEDERA
Solanum lycopersicum L. · Tomato
Rijk Zwaan Zaadteelt en Zaadhandel B.V.
Ribes nigrum L. · Blackcurrant
Stichting Tuin. Proef. (NL)/G Hanet (FR)
x Triticosecale Wittm. ex A. Camus · Triticale
Florimond Desprez Veuve et Fils, FR
Raphanus sativus L. var. sativus · Radish
Rijk Zwaan Zaadteelt en Zaadhandel B.V.
Rosa L. · Rose
HANS JUGEN EVERS
Cucumis sativus L. · Cucumber
Nunhems BV (NL)
Hordeum vulgare L. · Barley
Löhde Jörgen
Solanum lycopersicum L. · Tomato
Monsanto Vegetable IP Management B.V.
Triticum aestivum L. · Bread wheat
Lundin, Per /Svensson, Gunnar
Fragaria x ananassa Duchesne ex Rozier · Garden strawberry
Vissers International B.V.
Cucumis sativus L. · Cucumber
HAZERA SEEDS B.V.
x Triticosecale Wittm. ex A. Camus · Triticale
Danko Hodowla Roslin Sp.z.o.o.
Triticum aestivum L. · Bread wheat
Nordsaat Saatzucht GmbH Saatzucht Langenstein
Triticum aestivum L. · Bread wheat
Asur Plant Breeding SAS
Triticum aestivum L. · Bread wheat
Syngenta Participations AG
Rosa L. · Rose
Hans-Juergen Evers