The seed‐borne fungi of Chinese cabbage (Brassica pekinensis), their pathogenicity and control

Abstract

The pathogenicity and control of seed‐borne fungi of Chinese cabbage ( Brassica pekinensis ) were studied to evaluate the quality of imported seed lots on the Finnish market and to develop practical methods for seed health testing. Amongst the numerous fungal species in the seed lots, nine were found to be pathogenic on B. pekinensis seedlings, Alternaria raphani and A. brassicicola being the most common and the most pathogenic. A. brassicicola was effectively controlled by dressing seed with thiram or powdered Streptomyces griseoviridis . unlike A. raphani which was mostly located in the inner parts of the seed. Water agar was successfully used as an incubation medium for seed health testing. Surface sterilization of the seeds with sodium hypochlorite was used to determine the internal infection of A. raphani . A linear relationship between the incidence of A. brassicicola and A. raphani was demonstrated. Ten per cent of the seed lots were excluded from seedling production because of high infection with A. raphani .