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.
Hordeum vulgare L. · Barley
SERASEM
Cucurbita pepo L. · Field pumpkin
Przedsiebiorstwo Nasiennictwa Ogrodniczego i Szkolkarstwa w Ozarowie Mazowieckim Spolka z o.o.
Triticum aestivum L. · Bread wheat
Výzkumné Centrum Selton s.r.o., Selgen A.S.
Lactuca sativa L. · Lettuce
Rijk Zwaan Zaadteelt en Zaadhandel B.V.
Solanum lycopersicum L. · Tomato
Rijk Zwaan Zaadteelt en Zaadhandel B.V.
Vitis L. · Grapevine
Ing. Josef Veverka (CZ)
Raphanus sativus L. var. sativus · Radish
Hazera Seeds B.V.
Cucumis melo L. · Melon
CLAUSE TEZIER,S.A.
Cucumis melo L. · Melon
CLAUSE TEZIER,S.A.
Ribes uva-crispa L. · Gooseberry
Solanum lycopersicum L. · Tomato
Rijk Zwaan Zaadteelt en Zaadhandel B.V.
x Triticosecale Wittm. ex A. Camus · Triticale
LEMAIRE DEFFONTAINES S.A.S.
Hordeum vulgare L. · Barley
NORDSAAT Saatzucht GmbH Frau Dr. Lissy Kuntze
Hordeum vulgare L. · Barley
SVERIGES UTSÄDESFÖRENING SVALÖF
Triticum aestivum L. · Bread wheat
Poznanska Hodowla Roslin Sp. z o.o
Triticum aestivum L. · Bread wheat
W WEIBULL
Beta vulgaris Sugar Beet Group · Sugar beet
Syngenta Seeds
Pisum sativum L. · Pea
Poznanska Hodowla Roslin Sp. z o.o
Raphanus sativus L. var. sativus · Radish
Olaf Kunzemann
Malus domestica (Suckow) Borkh. · Apple
TYDEMAN E.M. (GB)
Cucumis sativus L. · Cucumber
NUNZA BV
Citrullus lanatus (Thunb.) Matsum. & Nakai · Watermelon
James Brusca
Cucumis sativus L. · Cucumber
SEMILLAS FITO, S.A.
Cucumis melo L. · Melon
Sakata Seed Corporation, JP