A New Sunflower Disease in Texas Caused by Diaporthe helianthi. Sam Yang, Research Plant Pathologist, USDA, ARS, Conservation and Production Research Laboratory, Bushland, TX 79012. R. W. Berry, Extension Plant Pathologist, Texas Agricultural Extension Service, Route 3, Box 213-AA, Lubbock 79401, E. S. Luttrell, Department of Plant Pathology, University of Georgia, Athens 30602, and T. Vongkaysone, Biological Technician, Texas A&M University, USDA, ARS, Conservation and Production Research Laboratory, Bushland 79012. Plant Dis. 68:254-255. Accepted for publication 14 November 1983. This article is in the public domain and not copyrightable. It may be freely reprinted with customary crediting of the source. The American Phytopathological Society, 1984. DOI: 10.1094/PD-68-254.

A stem canker and leaf spot of cultivated sunflower (Helianthus annuus) caused by the fungus Diaporthe helianthi (asexual stage Phomopsis helianthi) was observed for the first time in Texas. Symptoms on stems are light brown lesions with dark brown margins; lesions are variable in size and shape. Pycnidia are produced in affected areas. Lesions may also occur on leaf scars, petioles, and leaves. Pathogenicity of the fungus was demonstrated through inoculations to hybrid sunflower cultivars in the greenhouse. This is the first report of the disease in the United States.