Bacterial Blight of Crambe abyssinica in Missouri Caused by Xanthomonas campestris. J. D. Mihail, Department of Plant Pathology, University of Missouri, Columbia 65211. S. J. Taylor, P. E. Verslues, and N. C. Hodge. Department of Plant Pathology, University of Missouri, Columbia 65211; and Department of Plant Pathology, University of Florida, Gainesville 32611. Plant Dis. 77:569-574. Accepted for publication 19 January 1993. Copyright 1993 The American Phytopathological Society. DOI: 10.1094/PD-77-0569.

Crambe abyssinica is being evaluated as an oilseed crop for Missouri. During 1990–1992, a blight affecting leaves and stems was observed on virtually all plants growing in three experimental fields in central Missouri. A yellow-pigmented, gram-negative bacterium was consistently recovered from symptomatic tissue. A combination of physiological tests and gas chromatographic analysis of cellular fatty acids identified the bacterium as Xanthomonas campestris. The pathogen was closely related to X. c. armoraciae and X. c. campestris. The bacterium was found to be seedborne, contaminating 50–67% of tested seed of cv. Meyer. The bacterium was detected predominantly on the silicle and the surface of the seed coat and was possibly systemic within the seed. The bacterium infected several commercially important members of the genus Brassica and all crambe germ plasm sources tested. Symptom development in greenhouse tests also demonstrated the ability of the pathogen to move systemically through infected plants.

Keyword(s): Brassica campestris subsp. oleifera, Brassica carinata, Brassica hirta, Brassica juncea, Brassica napus subsp. oleifera, fatty acid analysis, host range, rapeseed, Xanthomonas campestris pv. vesicatoria.