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.
Vitis vinifera L. · Common grape vine
Prof. Dr.Dr.h.c. Gerhardt Alleweldt
Avena sativa L. · Oat
Danko Hodowla Roslin Sp.z.o.o.
Triticum aestivum L. · Bread wheat
SELGEN A.S
Triticum aestivum L. · Bread wheat
RAGT CZECH S.R.O.
Hordeum vulgare L. · Barley
INSTITUT NATIONAL DE LA RECHERCHE AGRONOMIQUE, FR
x Triticosecale Wittm. ex A. Camus · Triticale
NORDSAAT| NORDSAAT Saatzuchtgesellschaft mbH
Vitis vinifera L. · Common grape vine
Vivai Research Center, CZ
Lolium multiflorum Lam. · Italian ryegrass
DEUTSCHE SAATVEREDELUNG AG
Triticum aestivum L. · Bread wheat
RAGT 2N S.A.S
Cucurbita pepo L. · Field pumpkin
LA SEMIORTO SEMENTI SRL
Malus domestica (Suckow) Borkh. · Apple
Information not available - Contact NL authorities
Capsicum annuum L. · Bell pepper
Nunhems B.V.
Raphanus sativus L. var. sativus · Radish
Hazera Seeds B.V.
Cucumis melo L. · Melon
Zeraim Gedera Ltd (IL)
Solanum lycopersicum L. · Tomato
Seminis Vegetable Seeds
Triticum aestivum L. · Bread wheat
Secobra Saatzucht
Cucumis sativus L. · Cucumber
HM.CLAUSE
Cucumis melo L. · Melon
SEMILLAS FITO, S.A.
Hordeum vulgare L. · Barley
SVERIGES UTSÄDESFÖRENING SVALÖF
Triticum aestivum L. · Bread wheat
Hodowla Roslin Smolice Sp.z o.o Grupa IHAR
Cucumis sativus L. · Cucumber
Hazera Seeds B.V.
Triticum aestivum L. · Bread wheat
RAGT 2N S.A.S
Malus domestica (Suckow) Borkh. · Apple
Prof. Jaroslav Tupy c/o Institute of Experimental Botany
Cucumis melo L. · Melon
SYNGENTA SEEDS B.V.