Antifungal activity of leaf extracts of some medicinal trees against Macrophomina phaseolina

Present study was carried out to investigate the antifungal activity of leaf extracts of four medicinal trees namely Syzygium cumini (L.) Skeels, Eucalyptus citriodora Roxb. (family Myrtaceae) Azadirachta indica L. and Melia azedarach L. (family Meliaceae), against Macrophomina phaseolina (Tassi) Goid, the cause of charcoal rot disease in more than 500 plant species. Three organic solvents viz. methanol, chloroform and ethyl acetate were used for extraction from the leaves. Antifungal bioassays were carried out by using leaf extracts of 0.3, 0.6, …, 1.5% w/v concentrations in 100 ml conical flasks containing 15 ml of malt extract broth. In general, all the extracts significantly reduced the biomass of the target fungal species. However, there was significant difference among the plant species and extracting solvents for their antifungal activity. Highest antifungal activity was exhibited by ethyl acetate extract of A. indica followed by chloroform extract of the same tree species where different concentrations of these extracts reduced the fungal biomass by 81 to 90% and 78 to 84%, respectively as compared to control. Present study concludes that the leaf extracts of allelopathic trees especially ethyl acetate and chloroform extracts of A. indica contain natural fungicides which can be used for the management of M. phaseolina.