The antifungal activity of leaves of Datura metel for in vitro and in vivo management of Macrophomina phaseolina, the causal agent of root rot in mungbean [Vigna radiata (L.) R. Wilczek], was studied. In a laboratory bioassay, methanolic extracts of 0.5, 1.0, 1.5, 2.0 and 2.5 g/100 mL significantly reduced the fungal biomass by 36-47%. In a pot trial, dried powdered leaves of D. metel were mixed in soil at 0.5, 1.0 and 1.5% (w/w) with soil already inoculated with the target fungal pathogen. A negative control without fungal inoculation and leaf amendment, and a positive control with M. phaseolina inoculation only, were used for reference. Plant mortality due to M. phaseolina inoculation was significantly reduced by 42% and 80% due to 1.0 and 1.5% dry leaves amendments, respectively, as compared to positive control. There was a gradual increase in root and shoot growth of the plants with increase in dose of soil amendment. Generally, 1.5% dose significantly enhanced root and shoot growth as compared to positive control. M. phaseolina root rot in mungbean can effectively be managed by amending the soil with 1.5% dry leaf manure of D. metel.