In-vitro assessment of biocontrol agents against Sclerotium rolfsii causing white rot of onion in Manipur

Abstract

Antagonistic potential of five biocontrol agents were evaluated against Sclerotium rolfsii causing white rot of onion in Manipur. Trichoderma hamatum was most outstanding and effective against the test pathogen. The minimum mycelial growth of S. rolfsii was recorded in a dual culture with T. hamatum (2.0cm) followed successively by dual culture with T .harzianum (2.90cm) and T. viride (3.17cm) respectively. Trichoderma hamatum, T. harzianum and T. viride showed 78.88%, 67.77% and 64.77% inhibition on mycelial growth of the pathogen respectively. T. harzianum formed a translucent inhibition of 0.1cm at the interaction site but eventually overgrow the test pathogen and completely inhibited sclerotia formaton. Subsequently the test pathogen was also overgrown by T. hamatum and T. viride completely inhibiting sclerotia formation. Penicillium glabrum and P. citrinum were ineffective against S. rolfsii and both were overgrown by the pathogen.