Biocontrol efficacy of indigenous Trichoderma isolates against root-rot pathogens of French bean in Uttarakhand hills

Sixty cultures of Trichoderma were isolated from forty locations in Uttarakhand hills and screened for their ability to control root rot ol" French beam caused by Rhizoctonia solani (Kuhn) and Fusarium solani (Mart.) Sacc. Under laboratory screening by dual culture methodology, maximum inhibition of radial growth of R. solani (61.7%) was observed with isolate Tr-21, while isolate Tr-34 showed maximum inhibition of mycelial growth of F. solani (46.4%), Based on the results of in vitro screening, 7 isolates (Tr-5, 14, 17, 21, 28, 34 & 45) were selected for glasshouse studies. Talc formulation of the 7 isolates was prepared and isolates were applied as both seed and soil treatment in glasshouse studies. Although all the 7 isolates significantly reduced the incidence of root rot as compared to check, two isolates of T. harzianum viz., Tr-34 and Tr-14 were found most effective in glasshouse evaluation showing only 20.8 and 23.4 per cent root- rot, respectively, These isolates were statistically at par with seed treatment with carbendazim, which showed 21,1 per cent root-rot. Treatment with isolate Tr-34 also resulted in significantly higher germination per cent and better plant vigour as compared to untreated control.