We investigated the influence of Piriformospora indica on the antifungal principle of Spilanthes calva, a plant of high commercial value. An antifungal efficacy was shown by aqueous and petroleum ether extracts of S. calva against Fusarium oxysporum and Trichophyton mentagrophytes. The petroleum ether extract of S. calva was more effective than the aqueous extract in inoculated as well as uninoculated plants. The antifungal activity of the plant was enhanced due to the increase in spilanthol content after inoculation of P. indica.