In-vitro evaluation of bioagents and antibiotics against Ralstonia solanacearum causing brinjal wilt

Abstract

Bacterial wilt of brinjal and other solanaceous vegetables caused by Ralstonia solanacearum is the most destructive disease. The bacterial wilt disease is wide spread, affecting many solanaceous vegetable crops in India, especially in Karnataka and continue to pose serious problem to farmers. The In vitro studies carried out to find the effectiveness of antibiotics and antagonists in inhibiting the growth of R. solanacearum. The antibiotics viz., Amoxycilin, Cefixime, Ciprofloxacin, Tetracyclin, Norfloxacin and Streptomycin were highly effective at 500 – 750 ppm with the maximum inhibition. Among bacterial antagonists, Bacillus subtilis was very effective in inhibiting the growth of pathogen followed by Pseudomonas fluorescens and Bacillus megaterium. Among the antibiotics evaluated under pot culture in the green house, the treatments viz., Streptomycin, Cefixime and Tetracycline at 500 – 750 ppm were found very effective in reducing the population of R. solanacearum (0.0x104cfu/g of soil). Bacterial antagonists viz., P. fluorescens; B. megaterium and Bacillus subtilis reduced the pathogen population from (686.66 x 104cfu/g of soil) to 3.33x104, 4.33x104 and 7.33x104cfu/g of soil respectively.