Evaluation of Seed Treatments for ReducingAlternaria porriandStemphylium vesicariumon Onion Seed

During surveys in the Cape province of South Africa, Alternaria porri and Stemphylium vesicarium were found to be destructive seedborne pathogens of onion (Allium cepa L.). Six fungicides were evaluated for their efficacy in reducing pathogens both on seed and in culture. These fungicides included anilazine, benomyl, a carbendazim/flusilazole mixture, procymidone, tebuconazole, and thiram. An untreated control, hot water soak (50 C for 20 min), and a sodium hypochlorite treatment were also included for comparison. Treated seeds were rated for germination by the blotter method and by emergence and seedling growth in seedling trays in the glasshouse. None of the treatments eradicated A. porri and S. vesicarium from onion seeds