Diseases
Peronosporaceae
Downy mildew is a dangerous plant disease caused by oomycetes under high humidity conditions. It manifests as a characteristic growth on the underside of leaves and spotting, which leads to rapid death of vegetative mass and yield reduction.
Mentioned in descriptions 16 384 varieties reference book.
Downy mildew is a group of diseases caused by specialized oomycetes. The disease manifests as the appearance of yellowish or brown angular spots on the upper side of the leaves, delimited by veins. On the underside of the leaf, under humid conditions, a characteristic grey-violet, white, or bluish fuzzy growth forms. Pathogen development leads to yellowing and drying of leaves, stunting of plants, and deformation of fruits, which, in the case of high pathogen aggressiveness, can lead to crop death in a short period.
Disease development depends directly on meteorological conditions and agronomic practices. The pathogen prefers a cool, humid environment, with critical risk factors being heavy dew, fog, prolonged rain, high air humidity, and crop density. Optimal conditions for infection include nighttime temperatures in the range of +13…+20°C and the presence of droplet moisture on the leaf surface for more than 6 hours.
Assessment of variety resistance during variety testing is based on phytopathological recording of the degree of leaf damage, specialized screening of collection samples, and molecular analysis methods using DNA markers to find genetic donors of resistance. In production, a distinction is made between genetically resistant varieties possessing specific Dm-genes and tolerant forms capable of maintaining yield under infection due to active vegetative mass formation. Since new pathogen races can overcome genetic resistance, varieties require regular monitoring and renewal.
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.
Valerianella locusta (L.) Laterr. · Corn salad
Austrosaat (AT)
Vitis vinifera L. · Common grape vine
Yordan K. Ivanov, Vasil Y. Valchev, Georgi S. Petkov, Boris A. Muzyichenko (RU), Arif M. Aliev (RU), Ivan A. Kostrikin (RU)
Vitis L. · Grapevine
Agroscope, CH
Cucumis sativus L. · Cucumber
Bakumenko Nadiia Vasylivna, Pluzhnikova Liudmyla IEhorivna, Petrenko Mariia Petrivna, Kryvets` Dmytrii Olehovych, Pozniak Oleksandr Vasyl`ovych,
Cucumis melo L. · Melon
FRANCE GRAINES (FR)
Brassica oleracea L. (Cauliflower Group) · Cauliflower
Rijk Zwaan Zaadteelt en Zaadhandel B.V.
Allium cepa L. · Onion
Scott Hendricks
Allium cepa L. · Onion
Jaap Reus
Lactuca sativa L. var. crispa L. · Leaf lettuce
Kornelius Reinink
Vitis vinifera L. · Common grape vine
FONTAINE-TRANCHANT Maurice (FR)
Cucumis sativus L. · Cucumber
Kyrylov Mykhailo Ivanovych, Dubinin Serhii Volodymyrovych,
Lactuca sativa L. · Lettuce
Barb Neubert
Zea mays L. · Maize
KWS SAAT SE & CO.KGAA
Vitis vinifera L. · Common grape vine
INCONNU (FR)
Allium cepa L. var. cepa · Onion
Domaine Public (FR)
Lactuca sativa L. var. longifolia Lam. · Romaine lettuce
Kornelius Reinink
Vitis vinifera L. · Common grape vine
INCONNU (FR)
Helianthus annuus L. · Sunflower
Codisem, FR
Vitis vinifera L. · Common grape vine
INSTITUT NATIONAL DE LA RECHERCHE AGRONOMIQUE, FR
Vitis L. · Grapevine
INSTITUT NATIONAL DE LA RECHERCHE AGRONOMIQUE, FR
Vitis vinifera L. · Common grape vine
INCONNU (FR)
Vitis L. · Grapevine
INCONNU (FR)
Allium cepa L. · Onion
Deil Smit
Allium porrum L. · Leek
Fesenko IAroslav Ihorovych, Pozniak Oleksandr Vasyl`ovych, Fesenko Liubov Petrivna,