FIELD EFFICACY OF BACILLUS MEGATERIUM STRAIN NBAII 63 A NOVEL BIOCONTROL AGENT FOR THE MANAGEMENT OF BACTERIAL WILT BRINJAL CAUSED BY RALSTONIA SOLANACEARUM

Bacillus spp. were isolated from rhizosphere soils of various crops and forest  plants grown in different geographic areas and soil types of India. Among 100 isolates of Bacillus spp. screened under in vitro ten of them were found inhibitory against Ralstonia solanacearum which causes bacterial wilt of brinjal. Bacillus isolate NBAII 63 which was isolated from the soils of reserved forest of Western Ghats of Kerala was selected as promising one based on in vitro screening. The promising Bacillus isolate NBAII 63 was characterized and identified as Bacillus megaterium by 16S rDNA analysis. The bioefficacy of talc formulation of B. megaterium strain NBAII 63 was evaluated under  field for plant growth promotion and suppression of bacterial wilt in brinjal. A combined application of talc formulation of B. megaterium strain NBAII 63 as seed treatment, soil application, seedling root dip and foliar spray was found effective for the management of bacterial wilt of brinjal. Seedling establishment was good all the treatments. Reduction in wilt incidence up to 58.0% under field conditions were recorded in the combined application as compared to individual applications and control. Significant increase in growth parameters viz., root length (28.2cm) and shoot length (76.1 cm) of brinjal plants were recorded under field condition due to application B. megaterium as compared to control where it was 15.0 cm and 35.2 cm respectively. This study concluded that B.megaterium was found as potential biocontrol agent against R.solanacearum and its application in various ways reduced the wilt incidence under field condition.