A. 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 9 Minnesota counties surveyed in Sept. 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.