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
W. LEGUTKO PRZEDSIEBIORSTWO HODOWLANO NASIENNE SP.Z.O.O
Triticum aestivum L. · Bread wheat
Agri-Obtentions S.A., Institut National de Recherche pour l'Agriculture l'Alimentation et l'Environnement (INRAE)
Triticum aestivum L. · Bread wheat
Agri-Obtentions S.A., Institut National de Recherche pour l'Agriculture l'Alimentation et l'Environnement (INRAE)
Cucumis melo L. · Melon
UNITED GENETICS SEEDS CO
Cucumis sativus L. · Cucumber
Nunhems B.V.
Pisum sativum L. · Pea
Hurst, Gunson, Cooper, Taber, U.K.
Fragaria x ananassa Duchesne ex Rozier · Garden strawberry
Instytut Ogrodnictwa - Państwowy Instytut Badawczy (The National Institute of Horticultural Research)
Cucumis sativus L. · Cucumber
Rijk Zwaan Zaadteelt en Zaadhandel B.V.
Triticum aestivum L. · Bread wheat
I. Todorov, D. Atanasova, I. Panayotov, N. Tsenov, K. Kostov, I. Stoeva, I. Iliev, T. Petkova, V. Ivanova, I. Ivanova
Cucurbita pepo L. · Field pumpkin
Rijk Zwaan Zaadteelt en Zaadhandel B.V.
Cucumis sativus L. · Cucumber
Rijk Zwaan Zaadteelt en Zaadhandel B.V.
Lactuca sativa L. · Lettuce
Rijk Zwaan Zaadteelt en Zaadhandel B.V.
Cucumis sativus L. · Cucumber
FRANK FRANCIS
Daucus carota L. · Carrot
HM Clause, F
Cucumis melo L. · Melon
Sakata Vegetables Europe S.A.S.^^^Sakata Seed Corporation (SCC)
Cucumis melo L. · Melon
Rijk Zwaan Zaadteelt en Zaadhandel BV (NL)
Avena nuda L. · Naked oat
ABERYSTWYTH UNIVERSITY (GB)
Cucumis melo L. · Melon
Brassica napus var. napus · Rapeseed
LAMMERS SEED OPTIONS
Triticum aestivum L. · Bread wheat
Institut National de Recherche pour l'Agriculture l'Alimentation et l'Environnement (INRAE) , Agri-Obtentions S.A.
Beta vulgaris Sugar Beet Group · Sugar beet
Strube D&S GMBH
Triticum aestivum L. · Bread wheat
Cseuz Laszlo / Bona Lajos / Pauk Janos / Fonad Peter / Ovari Judit / Papp Maria / Beke Bela / Purnhauser Laszlo
Cucumis melo L. · Melon
SEMILLAS FITO, S.A.
Cucumis melo L. · Melon
Hollar Seeds, USA