Potential biocontrol agents for the management ofmacrophomina phaseolina, incitant of charcoal rot in maize

Six isolates of Trichoderma harzianum were tested as potential bio-control agents under dual culture plate technique and inhibition through volatile substances for their efficacy against Macrophomina phaseolina, a charcoal rot pathogen of maize. Hyderabad isolate of T. harzianum inhibited 62.34% radial growth of M. phaseolina whereas isolates from Coimbatore, Dharwad, Delhi and Pantnagar inhibited 58%, 56%, 53%, and 51% of radial growth, respectively, over control. The effect of these biocontrol agents on production and size of sclerolia was also studied. Hyderabad isolate was found most effective by giving 69.48% reduction in sclerotia production and 57.36% reduction in sclerotial size over control as compared to other isolates. The effect of volatile metabolites of these bioagents on radial growth, sclerotia size and production of M. phaseolina were also studied and it was observed that again Hyderabad isolate was able to inhibit 41% on radial growth, 67.39% reduction on production and 45.46% reduction on size of the sclerotia of pathogen over the control which was the maximum compared all the other isolates. The results indicated that Hyderabad isolate of T. harzianum could be used as a potential biocontrol agent for minimizing PFSR incidence by reducing the primary inoculum in the soil by restricting the production of sclerotia compared to other isolates tested.