Diseases
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.
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.
Solanum tuberosum L. · Potato
GERMICOPA SAS
Solanum tuberosum L. · Potato
Meijer Seedpotatoes and Research B.V.
Solanum tuberosum L. · Potato
R.P.GRAVELAND
Daucus carota L. · Carrot
Ger Beemsterboer
Daucus carota L. · Carrot
Vilmorin, F
Daucus carota L. · Carrot
ROGER FREEMAN
Solanum tuberosum L. · Potato
Germicopa SAS, FR
Helianthus annuus L. · Sunflower
Tierry Andre
Daucus carota L. · Carrot
Robert Oostveen
Solanum tuberosum L. · Potato
Mr. G. Kuper
Daucus carota L. · Carrot
Robert Priieur
Daucus carota L. · Carrot
Bejo Zaden B.V.
Daucus carota L. · Carrot
Bejo Zaden BV, NL-1749 ZH Warmenhuizen
Daucus carota L. · Carrot
Syngenta Seeds B.V.
Daucus carota L. · Carrot
Nunhems Zaden BV (NL)
Daucus carota L. · Carrot
Bejo Zaden, NL
Daucus carota L. · Carrot
Yurhen Berh
Brassica napus var. napus · Rapeseed
Norddeutsche, D
Daucus carota L. · Carrot
Syngenta Seeds, NL
Beta vulgaris Garden Beet Group · Garden beet
Bejo Zaden, NL
Daucus carota L. · Carrot
Vilomorin, F
Daucus carota L. · Carrot
Ger Beemsterboer
Helianthus annuus L. · Sunflower
Ragt 2n, F
Brassica napus var. napus · Rapeseed
Norddeutsche, D