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.
Solanum lycopersicum L. · Tomato
Monsanto Vegetable IP Management B.V.
Cucumis melo L. · Melon
Sakata Seed Corporation, JP
x Triticosecale Wittm. ex A. Camus · Triticale
Florimond Desprez Veuve et Fils, FR
Solanum lycopersicum L. · Tomato
Axia Vegetable Seeds B.V.
Capsicum annuum L. · Bell pepper
Rijk Zwaan Zaadteelt en Zaadhandel B.V.
Malus domestica (Suckow) Borkh. · Apple
THE KENT INCORPORATED SOCIETY
Cucumis sativus L. · Cucumber
RIJK ZWAAN WELVER GmbH, DE
Triticum aestivum L. · Bread wheat
Národné Polnohospodárske a Potravinárske Centrum (NPPC)
Cucumis sativus L. · Cucumber
Paul Degreef
Vitis L. · Grapevine
Institut National de Recherche pour l'Agriculture l'Alimentation et l'Environnement (INRAE)
Cucumis sativus L. · Cucumber
Rijk Zwaan Zaadteelt en Zaadhandel B.V.
Lactuca sativa L. · Lettuce
Rijk Zwaan Zaadteelt en Zaadhandel B.V.
Capsicum annuum L. · Bell pepper
Rijk Zwaan Zaadteelt en Zaadhandel B.V.
Hordeum vulgare L. · Barley
Sejet Planteforaedling I,S
Cucurbita pepo L. · Field pumpkin
HM.CLAUSE
Cucumis melo L. · Melon
Hazera, NL
Cucumis melo L. · Melon
Gautier Semences SAS (FR)
Cucurbita pepo L. · Field pumpkin
Syngenta UK Ltd
Cucumis sativus L. · Cucumber
Rijk Zwaan Zaadteelt en Zaadhandel B.V.
Cucumis sativus L. · Cucumber
Nunhems B.V.
Rosa L. · Rose
Poulsen Roser A/S
Lactuca sativa L. · Lettuce
Rijk Zwaan Zaadteelt en Zaadhandel B.V.
Secale cereale L. · Rye
Poznanska Hodowla Roslin Sp. z o.o
Cucumis sativus L. · Cucumber
RIJK ZWAAN ZAADTEELT EN ZAADHANDEL BV, NL