Screening and Selection of Potential Trichoderma Isolates for the Control of Cotton Seed Rot and Damping-off

Out of twelve Trichoderma isolates tested, cotton isolate T. viride (97) exhibited the fastest growth rate and strong antagonism against Rhizoctonia solani in vitro recording 56.2 per cent inhibition in dual culture. All the isolates tested enhanced cotton seed germination when treated with mycelial suspensions of bioagents in vivo. The disease incidence in bioagent treatments ranged between 14.8 to 32.4 per cent, while pathogen treatment recorded 82 per cent. Three isolates have recorded seedling vigour index above 2000, which was much better than fungicide treatment (1471) in blotter tests (Roll Towel Method). T. viride (32) recorded the maximum seed germination (86.4 per cent) and no incidence of post -emergence mortality under green house conditions. The seedling vigour index in bioagent treatments ranged between 1004 and 1866.