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.
Triticum aestivum L. · Bread wheat
PLANT BREEDING INTERNATIONAL CAMBRIDGE
Vitis vinifera L. · Common grape vine
INCONNU (FR)
Capsicum annuum L. · Bell pepper
Syngenta Crop Protection AG
Cucumis sativus L. · Cucumber
DE RUITER'S NIEUWE ROZEN
Beta vulgaris Sugar Beet Group · Sugar beet
Henning Friehe
Brassica napus var. napus · Rapeseed
BARENBRUG HOLDING| Barenbrug Holding B.V.
Triticum aestivum L. · Bread wheat
Zelder BV (NL)
Solanum lycopersicum L. · Tomato
Rijk Zwaan Zaadteelt en Zaadhandel B.V.
Solanum lycopersicum L. · Tomato
Kees Konst
Cucurbita pepo L. · Field pumpkin
VILMORIN, S.A.
Solanum melongena L. · Eggplant
INSTITUT NATIONAL DE LA RECHERCHE AGRONOMIQUE, FR
Scorzonera hispanica L. · Black salsify
ILVO-PLANT 39
Cucumis melo L. · Melon
Rijk Zwaan Zaadteelt en Zaadhandel B.V.
Fragaria x ananassa Duchesne ex Rozier · Garden strawberry
WASSENAAR| L.M. Wassenaar c/o Stichting DLO-Centr. v.Plantenveredelings-en Reproduktieonderz. (CPRO-DLO)
Hordeum vulgare L. · Barley
KOCH E.| Dr. Eberhard Koch in Fa. Saatzucht Bernburg GmbH / LENKE| Petra Lenke in Fa. Saatzucht Bernburg GmbH
Pisum sativum L. · Pea
PURE LINE SEEDS
Cichorium intybus L. (Industrial Chicory Group) · Chicory
S.A.S. Florimond Desprez Veuve & Fils
Capsicum annuum L. · Bell pepper
Monsanto Vegetable IP Management B.V.
Cucumis melo L. · Melon
Syngenta Seeds BV (NL)
Solanum lycopersicum L. · Tomato
Kees Konst
Malus domestica (Suckow) Borkh. · Apple
Station de Recherche de Wadenswil (CH)
Vitis vinifera L. · Common grape vine
Jorg Wolf, D
Avena nuda L. · Naked oat
Hodowla Roslin Strzelce Sp z.o.o. Grupa IHAR
Malus domestica (Suckow) Borkh. · Apple
Ústav experimentální botaniky AV ČR, v.v.i. (CZ)