Isolation, characterisation and evaluation of biocontrol agents against Fusarium wilt of capsicum in mid hills of Himachal Pradesh

Wilt caused by Fusarium oxysporum is one of the devastating diseases of bell pepper in mid hills of Himachal Pradesh. A survey of different capsicum growing regions of Solan district of Himachal Pradesh was carried out during the cropping season 2022 and 2023 with the objective of isolating biocontrol agents from the rhizospheric soil of capsicum, their efficacy against the pathogen under in vitro and pot culture conditions. Biocontrol agents (Trichoderma sp., Bacillus sp. and Pseudomonas sp.) were isolated from rhizospheric soil of healthy capsicum plants using the serial dilution method and were tested against 9 F. oxysporum isolates. Among fungal bioagents, Trichoderma atroviride was found the most effective in inhibiting the mycelial growth (73.71 %) in the dual culture method. Whereas, in case of bacterial biocontrol agents, Bacillus sp. 1 was found most effective during in vitro evaluation. Evaluation of biocontrol agents against Fusarium wilt of capsicum under pot culture condition revealed that T. atroviride was most effective and exhibited highest disease control (83.33 %), while Bacillus sp. 1 showed 50 % disease control against isolate 4 of F. oxysporum.