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.
Lolium x hybridum Hausskn. · Hybrid ryegrass
P.BREED.INST.WALES
Beta vulgaris Garden Beet Group · Garden beet
Nunhems Germany GmbH
Avena strigosa Schreb. · Black oat
P.H. Petersen Saatzucht Lundsgaard GmbH Herrn Asmus Sören Petersen
Hordeum vulgare L. · Barley
Syngenta Participations AG
x Triticosecale Wittm. ex A. Camus · Triticale
RAGT 2N S.A.S
Pisum sativum L. · Pea
SYNGENTA CROP PROTECTION AG / SYNGENTA CROP PROTECTION AG
Triticum aestivum L. · Bread wheat
KWS UK LTD
Rosa L. · Rose
Poulsen Roser A/S
Beta vulgaris Garden Beet Group · Garden beet
Sakata Vegetables Europe, F
Malus Mill. · Apple
Samus` Volodymyr Andriiovych, Pavliuchyk Anatolii Stepanovych,
Triticum aestivum L. · Bread wheat
State Stende Cereals Breeding Institute
Solanum lycopersicum L. · Tomato
BEN VAN DEN BOSCH
x Triticosecale Wittm. ex A. Camus · Triticale
Saatzucht Dr. Hege GbR
Hordeum vulgare L. · Barley
Zemědělský výzkumný ústav Kroměříž, s.r.o. (CZ)
Solanum lycopersicum L. · Tomato
Rijk Zwaan Zaadteelt en Zaadhandel B.V.
Hydrangea L. · Hydrangea
PREISIG| Walter Preisig
Ribes nigrum L. · Blackcurrant
Instytut Ogrodnictwa, PL
x Triticosecale Wittm. ex A. Camus · Triticale
Institut national de recherche pour l'agriculture, l'aliment (FR)/Agri Obtentions SA (FR)
x Triticosecale Wittm. ex A. Camus · Triticale
RAGT 2N S.A.S
Avena sativa L. · Oat
Danko Hodowla Roslin Sp.z.o.o.
Fragaria L. · Strawberry
THE BRITISH SOCIETY FOR HORTICULTURAL RESEARCH
Cucumis sativus L. · Cucumber
Wing Seed
Delphinium L. · Larkspur
LEGRO| R.A.H. Legro
Pisum sativum L. · Pea
DLF SEEDS A/S