Relationship of Pectolytic Clostridia and Erwinia carotovora Strains to Decay of Potato Tubers in Storage. E. Campos, Graduate Research Assistant, Department of Plant Pathology, University of Wisconsin, Madison 53706. E. A. Maher, Research Specialist, and A. Kelman, Professor, Department of Plant Pathology, University of Wisconsin, Madison 53706. Plant Dis. 66:543-546. Accepted for publication 22 September 1981. Copyright 1982 American Phytopathological Society. DOI: 10.1094/PD-66-543.

Prevalence of pectolytic clostridia and Erwinia spp. was assessed in samples of 100 partially decayed potatoes collected from each of seven commercial storage bins maintained at 5 C. Pectolytic clostridia were present in 22%, Erwinia carotovora subsp. carotovora (Ecc) in 13%, and Erwinia carotovora subsp. atroseptica (Eca) in 45% of the samples. In 58% of the samples from which clostridia were isolated, Ecc and/or Eca were also present. When healthy tubers from storage bins were injured uniformly and incubated at 20 C for 96 hr in a mist chamber, the proportion of clostridia to Erwinia isolates was significantly higher than in isolations directly from storage bin samples. In vitro, clostridia and Ecc, but not Eca, grew more rapidly at temperatures from 18 to 36 C.

Keyword(s): blackleg, Solanum tuberosum L.