No abstract

Ralstonia solanacearum causes bacterial wilt of solanaceous crop plants including brinjal, a most devastating in humid tropic. Ten different isolates of the causal bacterium R. solanacearum were isolated from naturally wilted brinjal plants collected from different locations of Dapoli tahsil and were characterized. Gram's staining and Potassium hydroxide solubility test revealed that all isolates of R. solanacearum were Gram negative in reaction and positive reaction for motility test. The all isolates of R. solanacearum were positive in acid production, gas production, starch hydrolysis, hydrogen sulphide production, cellulose decomposition and catalase activity. In case of methyl red test appearance of red colour indicates strong acid forming ability of the bacterium, while retaining of normal colour of the medium indicates alkalinity and negative reaction.

Bacterial wilt of brinjal caused by Ralstonia solanacearum is responsible for severe yield losses (10-90%) in farmer's field. A field experiment was conducted for the evaluation of different bio-agents, chemicals and plant extracts against bacterial wilt of brinjal at botany farm, DBSKKV, Dapoli during the Rabi, 2016-17 and 2017-18. The study revealed that all the treatments were significantly effective in controlling the disease. Seedling root dip in streptocycline @ 0.1% for 2 hrs. before transplanting was the most effective against the disease as it was recorded 50.63 percent disease reduction as compared to untreated and was followed by spot drenching of Pseudomonas fluorescens suspension 0.3% at the time of field preparation which recorded 48.10 percent disease reduction. Seedling root dip in bleaching powder solution (0.1%) for 2 hrs. before transplanting recorded 45.57 percent disease reduction as compared to untreated and it was at par with P. fluorescens treatment.