Study biocontrol efficacy of Pseudomonas fluorescens and Bacillus subtilis against Rhizoctonia solani and Fusarium oxysporum causing disease in tomato (Lycopersicon esculentum L.).

The present research deals with the study of antagonistic effect of microorganism against tomato disease caused by Rhioctonia solani Fusarium oxysporum. four bacterial strains of, Bacillus subtilis fife strain of Pseudomonas fluorescens were isolated from tomato field soil The antagonistic microorganisms against the pathogens were observed by Dual Culture Technique. P. fluorescens 5 isolate was found to show 81.3% 77.4 of growth inhibition against R.solani F. oxysporum respectively while B. subtilis177.4% 73.2 of growth inhibition against test pathogens respectively. In greenhouse field experiments, soil treatment with a suspension of biocontrol agents before planting reduced significantly the incidence of diseases on tomato plants , Under greenhouse conditions, B. subtilis and or P. fluorescens were shown to be effective reduction of the damping off of tomato seedlings , disease severity survival rate on tomato plants, also under field experiments enhanced values of growth parameters (number of branches, plant height, fresh dry weight )in tomato plants, also were gave higher records of yield yield components, (number of fruits, fruits yield of plants) compared to infected control. In general, P. fluorescens5 isolate were more effective than Bacillus subtilis1 isolates. This study suggests that bacterial antagonists might be potential biological control agents of tomato plants in Iraqi soil.