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.
Beta vulgaris Sugar Beet Group · Sugar beet
Syngenta Crop Protection AG
Cucurbita pepo L. · Field pumpkin
Syngenta Seeds BV (NL)
Trifolium pratense L. · Red clover
Dumon Agro France (FR)/Rijksstation Voor Plantenveredeling (BE)
Triticum aestivum L. · Bread wheat
Stefan Kontowski
Avena sativa L. · Oat
Lantmõnnen ek f÷r Plant Breeding department
Hordeum vulgare L. · Barley
Nordic Seed A/S
Cucumis sativus L. · Cucumber
Seminis Vegetable Seeds
Triticum aestivum L. · Bread wheat
Syngenta UK Ltd
Cucurbita pepo L. · Field pumpkin
Mazerreeuw Jaap
Triticum aestivum L. · Bread wheat
Bedoe Zoltan / Lang Laszlo / Szunics Laszlo / Balla Laszlo / Vida Gyula / Szunics Laszlone / Karsai Ildiko / Veisz Otto
Rosa L. · Rose
Springwood Consultants Ltd
Cucumis melo L. · Melon
Syngenta Seeds BV (NL)
Pisum sativum L. · Pea
Semenarna Ljubljana, SI
Beta vulgaris Sugar Beet Group · Sugar beet
STRUBE GMBH AND CO. KG
Triticum aestivum L. · Bread wheat
Sejet Planteforaedling I,S
Hordeum vulgare L. · Barley
Saatzucht Donau GmbH & Co.KG
Triticum aestivum L. · Bread wheat
KWS Lochow
Triticum aestivum L. · Bread wheat
Nina Pfeiffer, Erhard Ebmeyer
Beta vulgaris Sugar Beet Group · Sugar beet
Syngenta Seeds
Rosa L. · Rose
MEILLAND STAR ROSE
Triticum aestivum L. · Bread wheat
SAATZUCHT JOSEF BREUN GMBH and CO.KG
Helianthus annuus L. · Sunflower
Nidera S.A.
Brassica oleracea L. (Brussels Sprouts Group) · Brussels sprouts
Syngenta Seeds B.V. (NL)
Hordeum vulgare L. · Barley
Limagrain Europe S.A.S