Efficacy of Trichoderma chitinases against Rhizoctonia solani, the rice sheath blight pathogen

Thirty-five strains of Trichoderma viride and T. harzianum were screened fo r their antagonistic ability against the rice sheath blight pathogen, Rhizo ctonia solani. The strains that inhibited/overgrew the phytopathogenic fung us were considered effective. Light microscopic studies showed the antagoni sm of the hyphae of effective Trichoderma strains towards their host hyphae . Chitinase activity of Trichoderma culture filtrates was enhanced, when co lloidal chitin was used as the sole carbon source, instead of glucose. Chit inase pattern differed among the four select strains. The chitinase isoform s are induced differentially by carbon sources. The chitin affinity column fraction of Trichoderma culture filtrate inhibited, in vitro, the growth of R. solani.