Susceptibility of Corynebacterium sepedonicum to Disinfectants In Vitro. Gary A. Secor, Department of Plant Pathology, North Dakota State University, Fargo 58105. Lynda DeBuhr, and Neil C. Gudmestad. Department of Plant Pathology, North Dakota State University, Fargo 58105. Plant Dis. 72:585-588. Accepted for publication 28 January 1988. Copyright 1988 The American Phytopathological Society. DOI: 10.1094/PD-72-0585.

Susceptibility of Corynebacterium sepedonicum, the causal bacterium of potato ring rot, to 28 disinfectants and heat was evaluated in vitro under varying conditions. The quantitative suspension test was used to measure survival of bacteria after 5 and 10 min exposure of aqueous suspensions with and without addition of organic matter, and for bacteria dried on wood carriers. The organism did not survive following most treatments, but there was more consistent control at 10 min exposure than at 5 min. The efficacy of hypochlorites and iodines was reduced by organic matter. Dried bacteria were generally as susceptible to the disinfectants as bacteria in suspension. Secondary inoculum of C. sepedonicum on infested surfaces and equipment can be effectively eliminated by most disinfectants provided the bacteria are in contact with the disinfectant for a minimum of 10 min. A minimum temperature of 82 C for 5 min was required for complete inactivation of bacteria. Other limitations, such as safety and corrosiveness, may affect the choice of disinfectant to be used.