Evaluation of antagonists against Macrophomina phaseolina causing root rot of groundnut

Efficacy of antagonists isolated from rhizosphere was tested against different isolates of Macrophomina phaseolina collected from groundnut growing areas of Rajasthan and adjoining states. One isolate of Trichoderma harzianum, one isolate of Trichoderma viride and one isolate of Bacillus subtilis gave distinct antagonistic reactions against all the isolates of M. phaseolina in dual culture plate method. T. viride, T. harzianum and Bacillus sp. minimized root rot incidence in groundnut up to 73.34, 66.67 and 53.34%, respectively, when compared to control where 100% mortality was observed in pots. T. viride was most effective with organic amendments followed by T. harzianum and B. subtilis. T. viride along with neem (Azadirachta indica) cake minimized the disease up to 73.58% under field conditions.