Seed-Treatment Fungicides for Control of Seedborne Alternaria helianthi on Sunflower. K. K. Jeffrey, Graduate Research Associate, Department of Plant Pathology, Ohio State University, Ohio Agricultural Research and Development Center, Wooster 44691. P. E. Lipps, Assistant Professor, and L. J. Herr, Professor, Department of Plant Pathology, Ohio State University, Ohio Agricultural Research and Development Center, Wooster 44691. Plant Dis. 69:124-126. Accepted for publication 18 July 1984. Copyright 1985 The American Phytopathological Society. DOI: 10.1094/PD-69-124.

Inoculation of sunflower seed with conidial suspensions (about 410, 4,100, and 41,000/ml) of Alternaria helianthi resulted in development of disease symptoms on seedlings. Growth of A. helianthi in vitro was highly inhibited by chlorothalonil and thiabendazole; inhibited moderately by benomyl, captan, mancozeb, and thiram; inhibited slightly by iprodione; and inhibited the least by triadimenol. Seedborne A. helianthi was controlled in the field by seed treatment with benomyl, captan, chlorothalonil, iprodione, mancozeb, or triadimenol.