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 hybridum L. · Alsike clover
Lietuvos agrarinių ir miškų mokslų centras
Cucumis sativus L. · Cucumber
Rijk Zwaan Zaadteelt en Zaadhandel B.V.
Secale cereale L. · Rye
Poznanska Hodowla Roslin Sp. z o.o
Triticum durum Desf. · Durum wheat
Eurodur S.A.
Cucumis sativus L. · Cucumber
W. Atlee Burpee Company
Triticum aestivum L. · Bread wheat
Anne Ingver 20%, Merlin Haljak 10%, Reine Koppel 70% Centre of Estonian Rural Research and Knowledge
Cucumis melo L. · Melon
Syngenta Seeds BV (NL)
Avena nuda L. · Naked oat
ABERYSTWYTH UNIVERSITY (GB)
Cucumis sativus L. · Cucumber
Monsanto Vegetable IP Management B.V.
Impatiens L. · Balsam
MR.D.COLE
Cucumis melo L. · Melon
Rijk Zwaan Zaadteelt en Zaadhandel B.V.
Triticum aestivum L. · Bread wheat
Unisigma (FR)/Limagrain Europe (FR)
Fragaria x ananassa Duchesne ex Rozier · Garden strawberry
STICHTING DLO-CENTRUM VOOR PLANTENVEREDELINGS-EN
Cucumis sativus L. · Cucumber
Syngenta Seeds B.V.
Cucurbita pepo L. · Field pumpkin
HM.CLAUSE
Triticum durum Desf. · Durum wheat
Florimond Desprez Veuve et Fils, FR
Cucurbita pepo L. · Field pumpkin
Syngenta Crop Protection AG
Vitis L. · Grapevine
GUIDO CIPRIANI / ENRICO PETERLUNGER / GABRIELE DI GASPERO / MICHELE MORGANTE / SIMONE DIEGO CASTELLARIN / RAFFAELE TESTOLIN
Chrysanthemum L. · Chrysanthemum
Vandenberg Cornelis P.|Salinas, CA
Beta vulgaris Garden Beet Group · Garden beet
PLANTICO HODOWLA I NASIENNICTWO OGRODNICZE ZIELONKI SP. Z O.O.
Cucumis sativus L. · Cucumber
PanAmerican Seed Europe B.V.
Avena nuda L. · Naked oat
SELGEN A.S
Cucumis melo L. · Melon
Syngenta Seeds B.V.
Capsicum annuum L. · Bell pepper
Rijk Zwaan Zaadteelt en Zaadhandel B.V.