Carrot infection by Alternaria radicina in field conditions and results of laboratory tests.
Carrot black rot caused by the fungus Alternaria radicina (Meier) Drechsler et Eddy, the economically important disease of carrot (Daucus carota L.). Research was carried out in 2004 and 2005 in order to establish correlation between plant infestation in the field and laboratory experiments. To determine the incidence and severity of the disease in mature crop, a 5-degree scale was used, where 1 meant no visible disease symptoms and 5 meant total foliage infestation. Plants were rated individually and the disease index was calculated. Fungus pathogenicity in laboratory conditions was determined using a petiole assay and a root disc assay. The petiole assay was conducted during the vegetation period; basal parts of petioles detached from fully developed carrot leaves were put in contact with the growing A. radicina mycelium. The root disc assay was conducted during storage of carrot roots; root discs were inoculated with toothpicks overgrown by A. radicina mycelium. The isolate of A. radicina was pathogenic to petioles and carrot discs. Differences in the reaction of the examined cultivars in the field and laboratory experiments were revealed. However, no significant correlation between plant infestation in the field and the results of laboratory experiments were observed.
Szczeponek
A
A
Department of Genetics, Plant Breeding and Seed Science, Agricultural University of Kraków, Al. 29 Listopada 54, PL-31-425 Kraków, Poland.
Laszczak
P
P
Wesołowska
M
M
Grzebelus
D
D
Michalik
B
B
D000528:Alternaria / Q000472:pathogenicity*; D018552:Daucus carota / Q000382:microbiology* / Q000502:physiology*; D010935:Plant Diseases / Q000382:microbiology*; D018515:Plant Leaves / Q000254:growth & development / Q000382:microbiology*