Copper 8-Quinolinolate for Control of Corynebacterium michiganense pv. sepedonicum on Potato Seed Pieces and Handling Equipment. G. D. Easton, Plant Pathologist, Department of Plant Pathology, Irrigated Agriculture Research and Extension Center, Washington State University, Prosser 99350. M. E. Nagle, Agricultural Research Technologist III, Department of Plant Pathology, Irrigated Agriculture Research and Extension Center, Washington State University, Prosser 99350. Plant Dis. 69:422-425. Accepted for publication 5 November 1984. Copyright 1985 The American Phytopathological Society. DOI: 10.1094/PD-69-422.

Every year, Corynebacterium michiganense pv. sepedonicum (Cms) from infected certified seed potatoes and previously contaminated seed-handling equipment and storages is spread to clean seed. Aqueous sprays of the relatively noncorrosive copper 8-quinolinolate at 0.5^–3 kg a.i./L controlled Cms on contaminated wood, polyurethane foam, and urethane rubber surfaces found on potato seed-handling equipment in 6 yr of trials. When the chemical was sprayed on contaminated seed-piece surfaces, it failed to control the bacteria and was phytotoxic. The registered rate (0.5^–3 kg a.i./L) would be considered nonphytotoxic if sprayed on surfaces of seed-handling equipment. This rate eliminated most Cms on seed-handling equipment in commercial potato culture but did not guarantee against ring-rot contamination in a certified seed program.