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.
Cucumis sativus L. · Cucumber
Syngenta Seeds
Malus domestica (Suckow) Borkh. · Apple
Ústav experimentální botaniky AV ČR, v.v.i. (CZ)
Beta vulgaris Sugar Beet Group · Sugar beet
Strube-Dieckmann GmbH&Co.KG
Hordeum vulgare L. · Barley
PAJBJERG A,S (DK)
Hordeum vulgare L. · Barley
Sejet Planteforaedling I,S
Triticum aestivum L. · Bread wheat
Schweiger Weizen Gesellschaft Bürgerlichen Rechts
Cucumis sativus L. · Cucumber
Rijk Zwaan B.V.
Triticum aestivum L. · Bread wheat
Pflanzenzucht Oberlimpurg
Triticum aestivum L. · Bread wheat
NORDSAAT SAATZUCHT
Avena sativa L. · Oat
Serasem Recherches et Sélections Végétales
Triticum aestivum L. · Bread wheat
Wiersum Plantbreeding B.V.
Cucumis melo L. · Melon
Rijk Zwaan Zaadteelt en Zaadhandel B.V.
x Triticosecale Wittm. ex A. Camus · Triticale
SEMILLAS BATLLE, S.A.
Cucumis sativus L. · Cucumber
ZETA SEEDS S.L.
Triticum aestivum L. · Bread wheat
Wiersum Plantbreeding B.V.
Hordeum vulgare L. · Barley
SAATZUCHT STRENG-ENGELEN GMBH&CO. KG
Avena sativa L. · Oat
KWS Lochow
Brassica oleracea L. (Cauliflower Group) · Cauliflower
Ger Beemsterboer
Triticum aestivum L. · Bread wheat
Secobra Recherches
Lactuca sativa L. · Lettuce
Enza Zaden, NL
Triticum durum Desf. · Durum wheat
Südwestdeutsche Saatzucht GmbH&Co.KG
Fragaria x ananassa Duchesne ex Rozier · Garden strawberry
Simpson David
Cucumis melo L. · Melon
SEMILLAS FITO, S.A.
x Triticosecale Wittm. ex A. Camus · Triticale
Hodowla Roslin Strzelce Sp z.o.o. Grupa IHAR