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

Powdery Mildew of Soft Wheat 1 157 Apple Powdery Mildew 1 127 Powdery mildew of cucumber 1 031 Powdery mildew of rose 785 Powdery Mildew of Barley 758 Powdery mildew of melon 670 Tomato powdery mildew 351 Powdery mildew of zucchini 333 Powdery mildew of strawberry 281 Powdery mildew of pea 268 Powdery mildew of triticale 241 Powdery mildew of lettuce 231 Powdery mildew — sugar beet 186 Powdery mildew of pepper 185 Gooseberry powdery mildew 176 Powdery mildew of oats 176 Apple powdery mildew 153 Powdery mildew — durum wheat 151 Powdery Mildew of Black Currant 143 Grape Powdery Mildew 110 Peach Powdery Mildew 81 Powdery mildew of rye 76 Powdery Mildew of Bigleaf Hydrangea 73 Verbena powdery mildew 69

Found in these crops

Bread wheat 1 186 Apple 1 130 Cucumber 1 080 Grapevine 980 Rose 785 Barley 762 Melon 681 Common grape vine 512 Tomato 361 Field pumpkin 335 Garden strawberry 280 Pea 279

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.

E20S10452

Active

Capsicum annuum L. · Bell pepper

Enza Zaden Beheer B.V.

3 records

Active

Cucumis sativus L. · Cucumber

Syngenta Crop Protection AG

3 records

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Diseases

Fusarium wilt and blight 29 887
Viral mosaic diseases 22 022
Downy mildew 16 384
Leaf spot diseases 15 926
Rust 14 859
Verticillium wilt 12 175
Scab 12 064
Grey mold 7 316

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Text source

This summary is compiled from the publications listed in the sources and verified by an editor. It contains no legally significant information; it provides agronomic context for registry data rather than the registry data itself.