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.
Fragaria x ananassa Duchesne ex Rozier · Garden strawberry
Yosef Efraim|Hod HaSharon 45100, IL / Meizles Asaf|Hod HaSharon, IL
Pisum sativum L. · Pea
SYNGENTA SEEDS B.V. / SYNGENTA SEEDS B.V. / INRA MAROC / INRA MAROC / Vilmorin
Pisum sativum L. · Pea
Syngenta Crop Protection AG
Lactuca sativa L. · Lettuce
BEJO ZADEN
Bouvardia Salisb. · Bouvardia
JOHN M.F.DE JOHN
Solanum lycopersicum L. · Tomato
MARTIJN VAN STEE
x Triticosecale Wittm. ex A. Camus · Triticale
SVALÖF WEIBULL B.V.
x Triticosecale Wittm. ex A. Camus · Triticale
Lantmännen Seed B.V.^^^Burkhard Schinkel
Vicia sativa L. · Common vetch
Jouffray-Drillaud SA (FR)
x Triticosecale Wittm. ex A. Camus · Triticale
RAGT 2N S.A.S
Poa pratensis L. · Kentucky bluegrass
PURE SEED TESTING
Triticum aestivum L. · Bread wheat
RAGT 2N S.A.S
Triticum durum Desf. · Durum wheat
RAGT 2N S.A.S
Triticum aestivum L. · Bread wheat
RAGT 2N S.A.S
Lolium x hybridum Hausskn. · Hybrid ryegrass
RAGT 2N S.A.S
Pisum sativum L. · Pea
Seminis Vegetable Seeds
Triticum aestivum L. · Bread wheat
RAGT 2N S.A.S
Cucumis sativus L. · Cucumber
Robert Swinkels, Nunhems
Avena sativa L. · Oat
SELGEN A.S
Triticum aestivum L. · Bread wheat
RAGT 2N S.A.S
Cucumis sativus L. · Cucumber
Bayer Holland B.V.
Triticum durum Desf. · Durum wheat
RAGT 2N S.A.S
Capsicum annuum L. · Bell pepper
Rijk Zwaan Zaadteelt en Zaadhandel B.V.
Trifolium incarnatum L. · Crimson clover
SELGEN A.S