The internal infection of seeds by fungi was determined on potato dextrose medium. During the experimental years (2000–2001 and 2003) the number of seed-borne Alternaria micromycetes was high in winter and spring oilseed rape (Brassica napus var. oleifera), and spring turnip rape (Brassica rapa var. oleifera). In all cases the number of seeds infected with Alternaria spp. increased with an increase in Alternaria blight severity on siliqua. The number of seeds infected with Cladosporium spp. was much lower than the number of seed infected with Alternaria spp. In most cases the amount of seeds infected with Penicillium spp. increased with a reduction of Alternaria blight severity on siliqua. In all experimental years the seeds of oilseed rape and turnip rape was slightly infected with Botrytis spp., Mucor spp., Fusarium spp., Aspergillus spp.
Keywords: winter and spring oilseed rape, spring turnip rape, Alternaria blight, Alternaria spp.