Potential of Trichoderma spp. to control smut disease of sugarcane under sub-tropical conditions of India

Sugarcane smut, caused by Sporisorium scitamineum, is a sett borne disease causing considerable losses to sugarcane production especially in ratoon crops. In the present study, five isolates of Trichoderma, established from sugarcane rhizosphere (STr-83, 85 and 108) and root tissues (SER-10 and 42), were evaluated in vitro and in field for their potential to mange smut disease. The selected five isolates had previously established high antagonistic activity against sugarcane red rot and wilt diseases. The metabolites of all five isolates exhibited inhibitory activity against S. scitamineum resulting in considerable reduction in the pathogen growth (21.2 to 42.4%) as well as teliospore germination in vitro. Metabolites of endophytic isolate SER-10 showed highest inhibition in pathogen growth (42.4%) along with lowest teliospore germination. The suppressive potential of the five Trichoderma isolates when applied as sett and soil treatment was further evaluated in a field trial during 2021-22 crop season. Four of the five Trichoderma isolates resulted in considerable suppression in smut incidence (22.8 to 66.9% reduction) over control. Isolates STr-83 and isolate SER 42 were found most effective, reducing smut by 66.9 and 49.3 per cent, respectively, over control and also exhibited significantly higher yield (49.8% and 25.2% yield increase, respectively). These findings indicated that the identified Trichoderma isolates could be used for effective management of multiple sugarcane diseases, including smut, under field conditions.