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Ecology and Epidemiology

The Recovery of Corynebacterium sepedonicum from Sugar Beet Seed. William M. Bugbee, Research plant pathologist, U.S. Department of Agriculture, Agricultural Research Service, and adjunct professor, North Dakota State University, Fargo 58105 ; Neil C. Gudmestad, Assistant professor, Department of Plant Pathology, North Dakota State University, Fargo 58105. Phytopathology 78:205-208. Accepted for publication 24 August 1987. 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, 1988. DOI: 10.1094/Phyto-78-205.

Pathogenic strains of Corynebacterium sepedonicum, the cause of bacterial ring rot of potato, were recovered from sugar beet seeds that were produced in the Willamette Valley of Oregon in 1984. The bacterium was recovered directly from culture plates of diluted sugar beet seed extracts and from eggplants that had been inoculated with sugar beet seed strains of the bacterium. All strains of C. sepedonicum recovered from sugar beet seed were pathogenic to potato and eggplant. Indirect immunofluorescent antibody staining (IFAS) using highly specific monoclonal antibodies detected the bacterium in seed extracts. Seed extracts from one of seven cultivars produced in Oregon in 1985 and two of 26 foreign seed lots were IFAS positive, but the bacterium could not be recovered from dilution plates or eggplants that were inoculated with centrifuged seed extracts.