Incidence of Alternaria brassicicola (Schw.) Wiltsh. on Brassica oleracea seeds

Abstract

Samples of Brassica oleracea seed from Victoria, were tested for the presence of seed-borne Alternaria brassicicola and Alternaria brassicae. A. brassicicola was detected in 26 of 44 samples tested but A. brassicae was not detected in any. Between 24 and 37% of seed was infected, with 4-8% of infection found in the embryo tissues. Inoculation of seed with A. brassicicola resulted in loss of vigour in germinated seedlings, followed by death. The fungus retained its viability and pathogenicity on seed stored for up to 12 months. This investigation indicates that a high proportion of commercially available brassica seed are contaminated with A. brassicicola and may therefore be a primary source of disease for brassica crops in Australia.