IDENTIFICATION OF THE SOFT ROT BACTERIUM ISOLATED FROM CURING BURLEY TOBACCO LEAVES AND ENVIRONMENTAL CONDITIONS FOR DEVELOPMENT OF SOFT ROT LESION

버어리종담배 건조엽의 부패세균 Erwinia carotovora subsp. carotovora의 동정 및 부패환경에 관한 연구

The incitant of soft rot on burley tobacco leaves in the curing vinylhouse was identified as Erwinia carotovra subsp. carotovora on the basis of its physiological characters. The bacterium yew best at $25^{\circ}C$ and $30^{\circ}C$, but no growth was detectable at $40^{\circ}C$ in the nutrient broth for 24 hours period. Burley tobacco leaves inoculated with the bacteria (Ecc) produced typical soft rot lesions when the incubation temperature was 25 to $30^{\circ}C$ and the relative humidity was more than 8075, however, the lesion development was suppressed when the temperature was $40^{\circ}C$ and the relative humidity was below 80%. Significant negative correlation was found between hanging space in the curing vinylhouse and the incidence of soft rot on the tobacco leaves harvested in a rainy day regardless of streptomycin treatment.