Alternaria helianthi: A Pathogen of Sunflower New to Minnesota. W. W. Shane, Graduate Research Assistant, Department of Plant Pathology, University of Minnesota, St. Paul 55108. J. S. Baumer, Assistant Professor, Department of Plant Pathology, University of Minnesota, St. Paul 55108; and S. G. Sederstrom, Area Extension Agent, Crop Pest Management, West Central Experiment Station, Morris, MN 56267. Plant Dis. 65:269-271. Copyright 1981 American Phytopathological Society. DOI: 10.1094/PD-65-269.

Alternaria helianthi on oilseed sunflowers is reported for the first time in Minnesota. The fungus was first found associated with a severe seedling blight affecting more than 280 ha of sunflowers in June 1980. The fungus was later found in lesions on stems and leaves of plants in all 17 sunflower fields in nine Minnesota counties surveyed in September 1980. Greenhouse studies showed that stem, leaf, and petiole tissues are susceptible to infection by conidia of A. helianthi. All 27 entries of the 1980 National Oilseed Nursery were susceptible to A. helianthi.

Keyword(s): Helianthus annuus.