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
Monsanto, NL
Fragaria x ananassa Duchesne ex Rozier · Garden strawberry
Simpson David
Rosa L. · Rose
SWIM ROBERT (US)
Lactuca sativa L. · Lettuce
RIJK ZWAAN ZAADTEELT EN ZAADHANDEL BV
Hordeum vulgare L. · Barley
Vebsaat-und Pflanzgut
Pisum sativum L. · Pea
RAGT2n SAS
Hordeum vulgare L. · Barley
Carlsberg Research Laboratory
Cucumis melo L. · Melon
Rijk Zwaan Zaadteelt en Zaadhandel B.V.
Cydonia oblonga Mill. · Quince
Pisum sativum L. · Pea
RAGT 2N S.A.S
Malus domestica (Suckow) Borkh. · Apple
Institute of Experimental Botany AS CR, Czech Republic
Cucumis sativus L. · Cucumber
Bejo Zaden, NL
Pisum sativum L. · Pea
GSN Semences SAS (FR)
Cucumis sativus L. · Cucumber
Ger Beemsterboer
Cucurbita pepo L. · Field pumpkin
Syngenta Seeds, NL
Solanum lycopersicum L. · Tomato
Marcellinus Jacobus Johannes Mooij.
Cucumis sativus L. · Cucumber
Ger Beemsterboer
Triticum aestivum L. · Bread wheat
Limagrain UK
Solanum lycopersicum L. · Tomato
Rijk Zwaan Zaadteelt en Zaadhandel B.V.
Malus domestica (Suckow) Borkh. · Apple
Stichting Wageningen Research - Wageningen Plant Research, 6708 PB Wageningen
Pisum sativum L. · Pea
Zoldsegtermesztesi Kutato Intezet, H
Hordeum vulgare L. · Barley
Syngenta Seeds, UK
Prunus persica (L.) Batsch · Peach
Maillard Arsene / Maillard Laurence
Vitis vinifera L. · Common grape vine
Vivai Cooperativi Rauscedo, I