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.
Rosa L. · Rose
MEILLAND ALAIN ANTOINE
Avena sativa L. · Oat
Plant Breeding International Cambridge Ltd (GB)
Solanum lycopersicum L. · Tomato
Kees Konst
Cucumis sativus L. · Cucumber
Rijk Zwaan Zaadteelt en Zaadhandel B.V.
Raphanus sativus L. var. sativus · Radish
Rijk Zwaan Zaadteelt en Zaadhandel B.V.
Vitis L. · Grapevine
GUIDO CIPRIANI/GABRIELE DI GASPERO/MICHELE MORGANTE/ENRICO PETERLUNGER/RAFFAELE TESTOLIN/ SIMONE DIEGO CASTELLARIN
Solanum lycopersicum L. · Tomato
Bernardus van den Bosch
Beta vulgaris Fodder Beet Group · Mangelwurzel
Malopolska Hodowla Roslin Spolka z o.o.
Cucumis sativus L. · Cucumber
Seminis Vegetable Seeds
Triticum aestivum L. · Bread wheat
Poznanska Hodowla Roslin Sp. z o.o
Rosa L. · Rose
Meilland International
Pisum sativum L. · Pea
NEW YORK STATE AGRICULTURAL EXPERIMENT STATION - CORNELL UNIVERSITY
Rosa L. · Rose
Marie Louise Meilland (FR)
Triticum aestivum L. · Bread wheat
PIONEER HI-BRED INTERNATIONAL
Cucumis melo L. · Melon
Syngenta Seeds B.V.
Ribes nigrum L. · Blackcurrant
Silenko Volodymyr Oleksandrovych, Sherenhovyi Petro Zakharovych,
Solanum lycopersicum L. · Tomato
Rijk Zwaan Zaadteelt en Zaadhandel B.V.
Malus domestica (Suckow) Borkh. · Apple
Solanum lycopersicum L. · Tomato
Enza Zaden Bikhir B.V.
Beta vulgaris Sugar Beet Group · Sugar beet
Khoremans Stefan
Cucumis sativus L. · Cucumber
ANSEME SRL
Solanum lycopersicum L. · Tomato
De Ruiter Seed C.V.
Cucumis melo L. · Melon
Seminis Vegetable Seeds
Cucumis melo L. · Melon
ZERAIM GEDERA