Erwinia chrysanthemi:Reaction of Eight Plant Species to Strains from Several Hosts and to Strains of OtherErwiniaSpecies

Abstract

Six plant species (Chrysanthemum morifolium, Dieffenbachia amoena, D. maculata, Philodendron panduriforme, P. selloum and Syngonium podophyllum) were tested by standardized methods for reaction to 383 strains of E. chrysanthemi from 35 plant species, subspecies, or cultivars, and 99 strains of other Erwinia spp. All strains, except 2 strains of E. cypripedii and one of E. rhapontici, produced a positive reaction for C. morifolium and were separated into 10 plant reaction groups based on the reaction of the other 5 plant species. Strains (239) of E. chrysanthemi and 93 strains of other Erwinia spp. failed to produce a positive reaction in any of the 5 plant species. Only strains of E. chrysanthemi originally isolated from dieffenbachia caused a positive reaction for D. amoena and D. maculata. Only strains isolated from syngonium and 1 strain of E. carotovora carotovora from caladium and 1 strain from banana produced positive reactions for S. podophyllum; some syngonium strains and the caladium strain of E. c. carotovora also were positive for P. panduriforme and/or P. selloum. Positive reactions were produced in philodendron plants by 126 strains of E. chrysanthemi and 4 strains of E. c. carotovora isolated from 22 hosts. Carnation plants (Dianthus caryophyllus "Improved White Sim") were inoculated with 166 selected strains of E. chrysanthemi and 11 strains of other Erwinia spp. Symptoms were produced by 57 strains of E. chrysanthemi of which 48 of the strains originally had been isolated from Dianthus sp. Leaves of corn line NY3 .times. D50 were tested for reaction to 225 strains of E. chrysanthemi from 29 hosts and 44 strains of other Erwinia spp. Strains (73) of E. chrysanthemi from 14 hosts caused positive or slightly positive reactions of the corn leaves. All 8 plant species were tested for reactions to 108 of the 383 strains of E. chrysanthemi. Although all strains produced a positive reaction for chrysanthemum, 32 strains failed to produce a positive reaction for the other 7 plant species. The remaining 76 strains were classified into 10 plant reaction groups.