Synergistic effect of Bacillus subtilis and boric acid on management of bacterial wilt disease of potato caused by Ralstonia solanacearum in coastal plains of Odisha under field conditions

Field trial were conducted following split plot design in the year 2008–2009 and 2009–2010 under All India Co-ordinated Potato Research Project, Orissa University of Agriculture &Technology, Bhubaneswar with chemical soil amendments in main plots followed by individual and combine treatment of chemical and bio-agent treatments in the sub plots to study synergistic effect of Bacillus subtilis and boric acid on management of bacterial wilt of tomato caused by Ralstonia solanacearum (Smith) Yabuuchi. Combined potato seed treatment with B. subtilis BS-5 (6 × 106 CFU /ml) and 3% boric acid coupled with soil application of bleaching powder showed lower wilt incidence (9.55%) and enhanced yield (17.31 t/h) over control after 75 days of sowing under field conditions which is economical and also eco-friendly. With single application of boric acid (3%) or B. subtilis BS-5 (6 × 106 CFU /ml), wilt incidence were significantly higher 11.82 and 17.06% and yielded less healthy tubers 15.49 and 13.65 t/h, respectively. Though, the tubers treated with antibiotic streptocycline (150 ppm) followed by application of the same antibiotic at 10 days interval for four times after planting resulted in minimum wilting (3.83%) of plant and maximum of tuber yield (18.21 t/h) however it is more expensive and perilous.