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
Robert Oostveen
Solanum lycopersicum L. · Tomato
Monsanto Vegetable IP Management B.V.
Malus domestica (Suckow) Borkh. · Apple
SNC Elaris| FR
Triticum aestivum L. · Bread wheat
Saatzucht Donau GmbH & Co.KG
Triticum aestivum L. · Bread wheat
Delley Seeds and Plants
Lolium x hybridum Hausskn. · Hybrid ryegrass
L. DÆHNFELDT A/S
Pisum sativum L. · Pea
SEMO a.s
Triticum aestivum L. · Bread wheat
SELGEN A.S
Cucurbita pepo L. · Field pumpkin
Syngenta, NL
Cucumis sativus L. · Cucumber
ZKI, H
Cucumis sativus L. · Cucumber
Rijk Zwaan, NL
Cucumis melo L. · Melon
Rijk Zwaan Zaadteelt en Zaadhandel B.V.
Raphanus sativus L. var. sativus · Radish
Wim van der Heijden
Cucumis sativus L. · Cucumber
Rijk Zwaan, NL
Triticum durum Desf. · Durum wheat
WORLD WIDE WHEAT L.L.C.
Cucumis sativus L. · Cucumber
Rijk Zwaan Zaadteelt en Zaadhandel B.V.
Trifolium resupinatum L. · Persian clover
CENTRO DI RICERCA MIGLIORAMENTO GENETICO PIANTE AGRARIE S.R.L. C.M.G.P.A.
Triticum aestivum L. · Bread wheat
Borislav Kobiljski
Beta vulgaris Sugar Beet Group · Sugar beet
SESVANDERHAVE NV-SA, BE
Hordeum vulgare L. · Barley
Nickerson International Research S.N.C.
Triticum aestivum L. subsp. spelta (L.) Thell. · Spelt
TREVOR COPE SEEDS LIMITED
Beta vulgaris Garden Beet Group · Garden beet
Sakata Vegetables Europe, F
Triticum durum Desf. · Durum wheat
Saatzucht Donau GmbH & Co.KG
Cucumis sativus L. · Cucumber
Paul Degreef