Invitro assessment of antagonistic activity of trichoderma sp. against sarocladium oryzae causing sheath rot disease in paddy.

ABSTRACT

Invitro screening using the dual culture technique was undertaken to assess the potential of seven Trichoderma species. Trichoderma viride, Trichoderma lignorum, T.album, T.hamatum, T.harizanum, T.glaucum and T.koeningi as biological control agents against Sheath rot fungus Sarocladium oryzae. The test organisms were isolated from the paddy field where the disease occurred. Results revealed that all the test antagonists effectively checked the growth of the pathogen. The test antagonists grow faster than the pathogen and produced inhibition zones thereby limiting the growth of the pathogen. In solid medium, Trichoderma harizanum was the most antagonistic organism under the conditions of this study. The culture filtrates of the test fungi also inhibited the growth of Sarocladium oryzae with Trichoderma harizanum showing the highest percentage inhibition (79%) and T.viride and T.lignorum (78%). T.harizanum culture filtrate showed the highest percentage growth inhibition at 15% concentration in Sarocladium oryzae while T.viride and T.lignorum filtrates showed inhibition,at 25% respectively.