Diaporthe Stem Canker of Sunflower. L. J. Herr, Professor, Department of Plant Pathology, Ohio State University, Ohio Agricultural Research and Development Center, Wooster 44691. P. E. Lipps, Assistant Professor, and B. L. Watters, Graduate Research Associate, Department of Plant Pathology, Ohio State University, Ohio Agricultural Research and Development Center, Wooster 44691. Plant Dis. 67:911-913. Accepted for publication 15 April 1983. Copyright 1983 American Phytopathological Society. DOI: 10.1094/PD-67-911.

Stem canker, a new disease of oilseed sunflower, was first found in Ohio in 1980. A species of Diaporthe and its Phomopsis anamorph was isolated from the brown to black, later ash-grey, cankers. Characteristic symptoms were produced in the greenhouse and field on plants wound-inoculated at the time of flowering. Disease losses resulted from premature death and lodging of affected plants.