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Diseases

Powdery mildew

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.

Sources10

Breakdown by crop

Found in these crops

Varieties that feature this in their description

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.

Corylus avellana L. · Common hazel

RO
2 records

Ribes rubrum L. · Redcurrant

NL
2 records

Oromidas

Active

Cucumis melo L. · Melon

NL
2 records

Portogalia

Protection expired

Cucumis melo L. · Melon

RO
2 records

Malus domestica (Suckow) Borkh. · Apple

SI
2 records

Polana

Protection expired

Hordeum vulgare L. · Barley

SK
3 records

Solanum lycopersicum L. · Tomato

NL
3 records

Rivaner

Active

Vitis L. · Grapevine

CZ
4 records

Pisaxa

Active

Malus domestica (Suckow) Borkh. · Apple

DE
3 records

Olšava

Active

Vitis L. · Grapevine

CZ
3 records

Malus domestica (Suckow) Borkh. · Apple

NL
2 records

Corylus avellana L. · Common hazel

CZ
4 records

Preveli

Protection expired

Cucumis sativus L. · Cucumber

DK
2 records

Reluga

Active

Malus domestica (Suckow) Borkh. · Apple

CZ
8 records

Risager

Active

Ribes nigrum L. · Blackcurrant

NL
2 records

Pindos

Protection expired

Cucumis sativus L. · Cucumber

CZ
2 records

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