Foliar Disease of Sorghum Species Caused by Cercospora fusimaculans. G. C. Wall, Graduate Student, Department of Plant Pathology and Microbiology, Texas A&M University, College Station 77843. L. K. Mughogho, R. A. Frederiksen, and G. N. Odvody. Principal Pathologist, International Crops Research Institute for the Semi-Arid Tropics (ICRISAT), Patancheru, P.O., A.P. 502 324, India; Professor, Department of Plant Pathology and Microbiology, Texas A&M University, College Station 77843; and Assistant Professor, Texas Agricultural Experiment Station, Texas Agricultural Research and Extension Center, Corpus Christi 78410. Plant Dis. 71:759-760. Accepted for publication 1 April 1987. Copyright 1987 The American Phytopathological Society. DOI: 10.1094/PD-71-0759.

A Cercospora species with catenulate conidia was isolated on V-8-CaCO₃ from foliar lesions on Sorghum bicolor and S. halepense, and the original scalariform lesions were reproduced on sorghum cultivar TX7078. Samples of this foliar disease were mailed from Rwanda and from Comayagua, Honduras, to the Commonwealth Mycological Institute, Kew, U.K., for pathogen identification. The pathogen was identified as Cercospora fusimaculans. Field inoculations were performed in Choluteca, Honduras. This disease, which we hereby name ladder leaf spot, is distinguishable from gray leaf spot of sorghum caused by C. sorghi by its scalariform or ladderlike elliptical lesions. Sources of resistance to ladder leaf spot and gray leaf spot are apparently independent of each other. Ladder leaf spot has been observed on sorghum in Experiment, GA, at various locations in Texas, in Tampico, Mexico, throughout Honduras, and in El Salvador, Cuba, Colombia, Venezuela, Brazil, Rwanda, Malawi, and Zambia.