Occurrence of Race 2 of Exserohilum turcicum on Corn in the Central and Eastern United States. Edward G. Jordan, Assistant Professor, Department of Plant Pathology, University of Illinois, Urbana 61801. James M. Perkins, Assistant Plant Pathologist, Department of Plant Pathology, University of Illinois, Urbana 61801; Robert A. Schall, Plant Pathologist, Animal and Plant Health Inspection Service, USDA, Department of Plant Pathology, Purdue University, West Lafayette, IN 47901; and W. L. Pedersen, Assistant Professor, Department of Plant Pathology, University of Illinois, Urbana 61801. Plant Dis. 67:1163-1165. Accepted for publication 13 June 1983. Copyright 1983 American Phytopathological Society. DOI: 10.1094/PD-67-1163.

One hundred sixty samples of northern corn leaf blight (NCLB)-infected tissue collected from inbreds and hybrids of Zea mays in seven states during the 1979, 1980, and 1981 growing seasons were tested to determine which races of Exserohilum turcicum were present. Races were determined by the reaction of corn inbreds B37, B37Ht, B37Ht2, and Oh43Ht3 after inoculation with spore suspensions from infected tissue. Race 1 was virulent only on inbred B37, whereas race 2 was virulent on both B37 and B37Ht. None of the isolates were virulent on B37Ht2 or Oh43Ht3; therefore, race 3 was not identified. Race 2 was identified from NCLB tissue collected in Florida, Illinois, Indiana, Iowa, Pennsylvania, Minnesota, and New York, Race 2 was widespread in Illinois (53 counties) and Indiana (24 counties).