Variation in the Pathogenicity and Aggressiveness of Strains of Erwinia carotovora subsp. carotovora Isolated from Different Hosts. C. Smith, Plant Pathology Department, University of Florida, Gainesville 32611. J. A. Bartz, Plant Pathology Department, University of Florida, Gainesville 32611. Plant Dis. 74:505-509. Accepted for publication 29 December 1989. Copyright 1990 The American Phytopathological Society. DOI: 10.1094/PD-74-0505.

Thirty-seven strains of soft-rot erwinias isolated from lesions on different hosts in Florida varied in their physiological and pathological phenotype. Based on the production of phosphatase, acid from methyl- α -d-glucopyranoside, reducing substances from sucrose and growth at 36 C, 35 strains were typical or atypical members of Erwinia carotovora subsp. carotovora, and two strains were typical of E. chrysanthemi. All strains caused lesions in pepper and tomato fruit, potato tubers, and young tomato plants but varied in pathogenicity in the pseudostem of corn and in the stems of chrysanthemum, potato, and tobacco. Significant differences were found (P = 0.05) among the strains for aggressiveness in the tubers and fruit, but the relative aggressiveness in one host was not always associated with aggressiveness or pathogenicity in the other hosts. Strains isolated from a particular host were not always more aggressive than the others when inoculated to that host. Thus, certain strains of E. c. carotovora may exhibit a host specificity that is not related to their original host or to their relative aggressiveness in common hosts (such as potato tuber or tomato fruit).