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.
Daucus carota L. · Carrot
Paul Degreef
Cucumis melo L. · Melon
Rijk Zwaan Zaadteelt en Zaadhandel B.V.
Pisum sativum L. · Pea
SVS HOLLAND BV
Linum usitatissimum L. · Common flax
JTSD Ltd
Lactuca sativa L. · Lettuce
Nunhems B.V.
Rosa L. · Rose
MEILLAND INTERNACIONAL
Malus domestica (Suckow) Borkh. · Apple
Markus Kellerhals Agroscope
Fragaria x ananassa Duchesne ex Rozier · Garden strawberry
Terrance C. Moran^^^Michael D. Ferguson
Rosa L. · Rose
David J.C.Austin
Rosa L. · Rose
David Austin
Rosa L. · Rose
David J.C.Austin
Vitis L. · Grapevine
SUN WORLD INTERNATIONAL
Vitis vinifera L. · Common grape vine
David W. Cain, PhD.
Rosa L. · Rose
David J.C.Austin
Rosa L. · Rose
David J.C.Austin
Rosa L. · Rose
David J.C.Austin
Hordeum vulgare L. · Barley
Limagrain Europe S.A.S. (FR)
Triticum aestivum L. · Bread wheat
KWS Lochow
Triticum aestivum L. · Bread wheat
Limagrain Europe S.A.
Hordeum vulgare L. · Barley
KWS LOCHOW GMBH, DE
Triticum aestivum L. · Bread wheat
Rainer Bouze
Triticum aestivum L. · Bread wheat
KWS Lochow
Hordeum vulgare L. · Barley
LIMAGRAIN EUROPE
Hordeum vulgare L. · Barley
KWS Lochow GmbH, Bergen DE