Identification of Erwinia chrysanthemi as a Soft-Rot-Inducing Pathogen of Grain Sorghum. S. G. Jensen, Research Plant Pathologist, USDA, ARS, 406 m Plant Science Hall, University of Nebraska, Lincoln 68583. W. R. Mayberry, Microbiologist, Department of Microbiology, College of Medicine, East Tennessee State University, Johnson City 37601; and J. A. Obrigawitch, Research Assistant, Department of Plant Pathology, University of Nebraska, Lincoln 68583-0722. Plant Dis. 70:593-596. Accepted for publication 27 December 1985. 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, 1986. DOI: 10.1094/PD-70-593.

A bacterial pathogen was isolated from pre-boot-stage grain sorghum plants suffering from a soft rot of the stalk. Koch’s postulates were satisfied with a bacterium that caused soft rot only at high temperatures (>30 C) but was pathogenic to several commercial sorghum genotypes. The pathogen was identified as an isolate of Erwinia chrysanthemi on the basis of comparisons with authentic cultures for standard morphologic-metabolic criteria, composition of soluble cellular proteins (by polyacrylamide gel electrophoresis), and composition of cellular fatty acids (by gas chromatography).