Diseases

Alternaria blight

Alternaria

Alternaria blight is a complex of fungal diseases characterized by the appearance of dark spots with concentric zonation on plant organs. The disease leads to tissue necrosis, a reduction in photosynthetic activity, and significant yield losses.

Mentioned in descriptions 2 812 varieties reference book.

Alternaria blight manifests as dark, brown, or black spots that often have a characteristic concentric pattern resembling a target. On leaves, the spots eventually coalesce, causing necrosis, while on stems and fruits, depressed areas form, which, in conditions of high humidity, are accompanied by a velvety olive-colored sporulation coating.

Disease development is most intense at temperatures from +20 to +30°C and high air humidity, including the presence of free moisture. The risk of infection increases significantly with dense planting, mechanical tissue damage, and mineral nutrient deficiencies, as the pathogens often act as a secondary infection attacking weakened plants.

Varietal resistance to Alternaria blight is achieved through a combination of passive barriers, such as tissue structure features, and active responses, such as hypersensitivity, which blocks pathogen development. Resistance evaluation of varieties in breeding is conducted through field trials on natural infestation sites and provocation methods using artificial inoculation, which allows for the differentiation of varieties by the degree of infection.

Sources10

Breakdown by crop

Found in these crops

Tomato 224 Carrot 193 Rapeseed 117 Sunflower 75 Potato 64 Rapeseed 53 White cabbage 25 Mandarin orange 23 Citrus 23 Bell pepper 20 Leek 14 Broccoli 13

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.

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Diseases

Powdery mildew 33 570
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

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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.