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.
Daucus carota L. · Carrot
Ger Beemsterboer
Helianthus annuus L. · Sunflower
Petran Alexandru-Viorel
Petroselinum crispum (Mill.) Nyman ex A. W. Hill · Parsley
Jan Draaistra
Vitis L. · Grapevine
Lactuca sativa L. · Lettuce
PETOSEED CO
Pisum sativum L. · Pea
Syngenta Seeds B.V.
Helianthus annuus L. · Sunflower
PIONEER OVERSEAS CORPORATION US
Helianthus annuus L. · Sunflower
NUSEED EUROPE
Helianthus annuus L. · Sunflower
PIONEER OVERSEAS CORPORATION
Helianthus annuus L. · Sunflower
PIONEER OVERSEAS CORPORATION
Helianthus annuus L. · Sunflower
NUSEED EUROPE
Spinacia oleracea L. · Spinach
ASGROW SEED CO
Lactuca sativa L. · Lettuce
MoravoSeed, CZ
Lactuca sativa L. · Lettuce
Enza Zaden B.V.
Raphanus sativus L. var. sativus · Radish
Hazera Seeds B.V.
Cucumis sativus L. · Cucumber
Seminis Vegetable Seeds
Lactuca sativa L. · Lettuce
Enza Zaden Beheer B.V.
Cucumis sativus L. · Cucumber
Selekcijos ir sėklininkystės firma ,,Manul"
Helianthus annuus L. · Sunflower
MIHAIL NIKOLOV HRISTOV
Cucumis sativus L. · Cucumber
Bruinsma Seeds B.V.
Helianthus annuus L. · Sunflower
Surovikin Volodymyr Mykolaiovych, Pihrova Svitlana Kuz`mivna, Detsina Oleksandr Oleksandrovych, Ilatovs`kyi Volodymyr Platovych, Borodin Serhii Heorhiiovych,
Lactuca sativa L. · Lettuce
Rijk Zwaan, NL
Helianthus annuus L. · Sunflower
PANAM FRANCE SARL
Lactuca sativa L. · Lettuce
BEJO ZADEN