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 multiflorum Lam. ssp. italicum (A. Br.) Volkart · Italian ryegrass
DEUTSCHE SAATVEREDELUNG AG
Avena sativa L. · Oat
SIA(COM.MADRID)INIA(MADRI
Ribes nigrum L. · Blackcurrant
Estonian University of Life Sciences Institute of Agricultural and Environmental Sciences Polli Horticultural Research Centre
Cucumis melo L. · Melon
Nunhems B.V., Laboratoire ASL S.N.C.
Capsicum annuum L. · Bell pepper
ALEJANDRO MARTIN CARA
Cucumis sativus L. · Cucumber
De Ruiter Zonen (HR)
Solanum lycopersicum L. · Tomato
Axia Vegetable Seeds B.V.
Cucumis melo L. · Melon
EVERGROW SEED CO. LTD
Cucumis melo L. · Melon
Syngenta Crop Protection AG, CH
Solanum lycopersicum L. · Tomato
Enza Zaden Beheer B.V.
Cucumis melo L. · Melon
Asgrow France SA (FR)
Cucumis sativus L. · Cucumber
Vilmorin-Mikado SAS (FR)
Solanum lycopersicum L. · Tomato
Rijk Zwaan Zaadteelt en Zaadhandel B.V.
Phaseolus vulgaris L. · Common bean
PRINC.ASTURIAS(CAPP)/INIA
Lactuca sativa L. · Lettuce
Enza Zaden Beheer B.V.
Cucumis melo L. · Melon
Enza Zaden Beheer B.V.
Lactuca sativa L. · Lettuce
Vilmorin-Mikado SAS (FR)
Cucumis melo L. · Melon
Nunhems B.V., Laboratoire ASL S.N.C.
Cucurbita pepo L. · Field pumpkin
PEOTEC S.R.L.
Solanum lycopersicum L. · Tomato
Gautier Semences SAS (FR)
Solanum lycopersicum L. · Tomato
Rijk Zwaan Zaadteelt en Zaadhandel B.V.
Solanum lycopersicum L. · Tomato
Enza Zaden Beheer B.V.
Capsicum annuum L. · Bell pepper
ALEJANDRO MARTIN CARA
Vitis vinifera L. · Common grape vine
InnoVitis GmbH