Prevalence of bacterial spot in tomato fields of Karnataka and effect of biological seed treatment on disease incidence

Bacterial spot disease of tomato caused by Xanthomonas vesicatoria was studied during the field survey in the Karnataka state, India. The disease incidence ranged from 22% to 50%. The pathogen was isolated from the infected plant material and seed samples. In the laboratory the pathogen was isolated following the routine laboratory assay method i.e. direct plating method using Tween B medium. Further the pathogen was confirmed by biochemical, physiological, hypersensitivity in tobacco (Nicotiana tabaccum) plants and finally the pathogenicity tests. Biological seed treatment with antagonistic Pseudomonas fluorescens improved the seed quality (p=0.05) under laboratory conditions and tremendously decreased the bacterial spot disease incidence in field.