Biocontrol properties of indigenous Trichoderma isolates from North-east India against Fusarium oxysporum and Rhizoctonia solani

Abstract

Trichoderma is one of the best known and well described biocontrol fungi for its lytic activity and antagonistic properties against phytopathogens. In the present study, a total of 114 isolates of Trichoderma were isolated from the soil collected from diverse climatic conditions of Manipur on selective medium. Out of the total isolates, 80% shows high degree of antagonism against Fusarium oxysporum while 68% Trichoderma isolates gives strong activity against Rhizoctonia solani. Based on their antifungal activity in dual plate assay, 25 isolates were selected for further analysis. The interaction between the Trichoderma and fungal pathogens were examined microscopically. Several biocontrol mechanisms were studied and analysis data showed that the clearing zone diameter of protease activity of these indigenous Trichoderma isolates ranges from 10 to 60 mm. Among them, 84% gave high chitinase activity and their activity ranges between 10 to 85 mm. whereas, ß-1,3-glucanases activity showed a clearing zone diameter ranging from 10 to 70 mm. Based on their relative biocontrol potency, three indigenous Trichoderma isolates (T10, T17 and T83) were selected for pot culture experiment for testing their biocontrol efficacy against wilting and damping off diseases of common beans. Among all the treatments, T83 showed better biocontrol efficacy against the two test fungus as compared to the exotic Trichoderma harzianum (ITCC No. 6276) strain.

Keywords: Antagonistic, Chitinase, Fusarium oxysporum, protease, Rhizoctonia solani, Trichoderma sp