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
Nunhems B.V.
Cucumis sativus L. · Cucumber
Matthijs Groot
Lactuca sativa L. · Lettuce
Rijk Zwaan Zaadteelt en Zaadhandel B.V.
Avena sativa L. · Oat
Selgen a.s., CZ
Avena sativa L. · Oat
SAATZUCHT FIRLBECK GMBH&CO.KG
Triticum aestivum L. · Bread wheat
Selgen, a.s. Vyzkumne centrum SELTON, s.r.o.
Secale cereale L. · Rye
Danko Hodowla Roslin Sp.z.o.o.
Triticum aestivum L. · Bread wheat
LEMAIRE DEFFONTAINES SEMENCES
x Triticosecale Wittm. ex A. Camus · Triticale
Philippe Lemaire Ets. Lemaire Deffontaines
Pisum sativum L. · Pea
NOVARTIS SEEDS
Hordeum vulgare L. · Barley
Saatzucht Donau GmbH & Co.KG
Vitis L. · Grapevine
GUIDO CIPRIANI/GABRIELE DI GASPERO/MICHELE MORGANTE/ENRICO PETERLUNGER/RAFFAELE TESTOLIN/ SIMONE DIEGO CASTELLARIN
Malus domestica (Suckow) Borkh. · Apple
Purdue Research Foundation (US)
Cucurbita pepo L. · Field pumpkin
W. LEGUTKO PRZEDSIEBIORSTWO HODOWLANO NASIENNE SP.Z.O.O
Triticum aestivum L. · Bread wheat
Selgen, a.s. Vyzkumne centrum SELTON, s.r.o.
Hordeum vulgare L. · Barley
NORDSAAT Saatzucht GmbH Frau Dr. Lissy Kuntze
Triticum aestivum L. · Bread wheat
Secobra Saatzucht
Cichorium endivia L. · Endive
Rijk Zwaan Zaadteelt en Zaadhandel BV (NL)
Solanum lycopersicum L. · Tomato
Kees Konst
Hordeum vulgare L. · Barley
Claus Einfeldt
Pisum sativum L. · Pea
Volmary Ltd
Triticum aestivum L. · Bread wheat
Svensson, Gunnar/Jönsson, Jan Ö
Cucumis sativus L. · Cucumber
SYNGENTA SEEDS B.V.
Beta vulgaris Sugar Beet Group · Sugar beet
STRUBE D and S GMBH