Abstract
The soil-borne fungal plant pathogen Macrophomina phaseolina (Tassi) Goid. causes rot disease in about 500 plant species
worldwide. This study was conducted to assess the antifungal potential of an allelopathic grass Imperata cylindrica (L.)
Beauv. for the management of this devastating plant pathogen. In laboratory bioassays, various concentrations viz. 0, 0.5,
1.0, …, 3.0 g 100 mL-1 of methanolic shoot, root and inflorescence extracts of the test allelopathic grass were appraised for
their antifungal activity against the pathogen. Generally, higher concentrations of methanolic extracts of all the three parts of
the grass exhibited variable antifungal activity. Shoot extract proved to be the most effective. All the concentrations of shoot
extract significantly reduced the fungal biomass by 29–76% over control. Methanolic shoot extract was further fractionated
using n-hexane, chloroform, ethyl acetate and n-butanol. In antifungal activity bioassays of these fractions, chloroform
fraction was found to be the most effective followed by n-hexane and aqueous fractions. All the concentrations of these
fractions significantly reduced fungal biomass. Various concentrations of n-hexane, chloroform and aqueous fraction reduced
fungal biomass by 27–97%, 68–100% and 32–100%, respectively. Present study concludes that chloroform fraction of
methanol shoot extract of I. cylindrica possesses highly active antifungal constituents for the management of M. phaseolina.
