Role of diseased plant debris, seed and soil in perpetuation of alternaria blight of radish

Alternaria brassicae causing Alternaria blight of radish remained viable in diseased plant debris under both laboratory and field conditions for seven months till the next sowing season. Plant debris stored in the laboratory conditions caused infection in 16.6% seedling and 11.5% infected seedlings were recorded when stored under field conditions, 30.7 and 23.0% seedlings were found infected when naturally infected and artificially infected seeds were sown in autoclaved soil, respectively. Sterilized seeds sown in naturally infested soil resulted in 15.3% disease incidence while 18.5% infected. Seedlings were observed in case of sterilized seeds sown in autoclaved infested soil.