Effective biocontrol of Fusarium wilt in castor (Ricinius communis L.) with Bacillus sp. in pot experiments

Fusarium wilt is a destructive and economically damaging disease of castor (Ricinus communis L.) in India, caused by Fusarium oxysporum f. sp. ricini. It is not practical to control the soil-borne diseases using chemicals, biological control is a realistic approach for management of Fusarium wilt. The objective of this research was to identify antagonistic bacteria for management of the disease. Bacterial cultures were isolated from castor rhizosphere soil samples and identified 42 antagonistic cultures based on dual culture method. These cultures were identified as Bacillus sp. by sequencing of 16 S rRNA. Under greenhouse conditions biocontrol efficiency of these isolates were evaluated by pot culture experiments. Plants were continuously observed for the disease symptoms, after 50 days disease suppression rate was calculated. Isolates E*37, P*37, P*40 and P*46 showed 65-70% of disease suppression, these can be used as potential biocontrol agents for castor wilt management after evaluating them under field conditions.