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.
Pisum sativum L. · Pea
Toft Plant Breeding APS
Rosa L. · Rose
POULSEN ROSER A/S
Cucumis sativus L. · Cucumber
Yost van den Eiden
Avena strigosa Schreb. · Black oat
Panam France sarl (FR)/Panam Chili (CL)
Triticum aestivum L. · Bread wheat
SARL ADRIEN MOMONT ET FILS, FR
Rosa L. · Rose
Wilhelm Kordes (DE)/Margarita Kordes (DE)/Tim-Hermann Kordes (DE)
x Triticosecale Wittm. ex A. Camus · Triticale
Danko Hodowla Roslin Sp z.o.o. (PL)
Hordeum vulgare L. · Barley
Saatzucht Donau, A
Fragaria x ananassa Duchesne ex Rozier · Garden strawberry
Pierron-Darbonne Alexandre
Fragaria x ananassa Duchesne ex Rozier · Garden strawberry
Philippe Roudeillac c/o CIREF
Pisum sativum L. · Pea
Nunhems Zaden BV (NL)
Cucumis sativus L. · Cucumber
Bejo Zaden B.V.
Rosa L. · Rose
Weeks Roses Inc (US)
Pisum sativum L. · Pea
Pure Line Seeds, USA
Pisum sativum L. · Pea
SYNGENTA SEEDS B.V. / SYNGENTA SEEDS B.V. / INRA MAROC / INRA MAROC / Vilmorin
Daucus carota L. · Carrot
Vilmorin, F
Fragaria x ananassa Duchesne ex Rozier · Garden strawberry
Stoppel Peter
Pisum sativum L. · Pea
Milika Buurman
Rosa L. · Rose
Interplant Roses B.V
Hordeum vulgare L. · Barley
Saaten-Union
Cucumis sativus L. · Cucumber
Paul Degreef
Daucus carota L. · Carrot
Paul Degreef
Pisum sativum L. · Pea
Syngenta Seeds, NL
Malus domestica (Suckow) Borkh. · Apple
SNC Elaris| FR