Abstract—Macrophomina phaseolina is a devastating soil-borne fungal plant pathogen that causes charcoal rot disease in many economically important crops worldwide. So far, no registered fungicide is available against this plant pathogen. This study was planned to examine the antifungal activity of an allelopathic grass Cenchrus pennisetiformis (Hochst. & Steud.) Wipff. for the management of M. phaseolina isolated from cowpea [Vigna unguiculata (L.) Walp.] plants suffering from charcoal rot disease. Different parts of the plants viz. inflorescence, shoot and root were extracted in methanol. Laboratory bioassays were carried out using different concentrations (0, 0.5, 1.0, …, 3.0 g mL -1 ) of methanolic extracts of the test allelopathic grass species to assess the antifungal activity against the pathogen. In general, extracts of all parts of the grass exhibited antifungal activity. All the concentrations of methanolic extracts of shoot and root significantly reduced fungal biomass by 20–73% and 40–80%, respectively. Methanolic shoot extract was fractionated using n-hexane, chloroform, ethyl acetate and n-butanol. Different concentrations of these fractions (3.125, 6.25, …, 200 mg mL -1 ) were analyzed for their antifungal activity. All the concentrations of n-hexane fraction significantly reduced fungal biomass by 15–96% over corresponding control treatments. Higher concentrations (12.5–200 mg mL -1 ) of chloroform, ethyl acetate and n-butanol also reduced the fungal biomass significantly by 29–100%, 46–100% and 24–100%, respectively. Keywords—Antifungal activity, Cenchrus pennisetiformis, Macrophomina phaseolina, natural fungicides I. INTRODUCTION ACROPHOMINA PHASEOLINA is an important fungal pathogen, infecting more than 500 plant species and also has the ability to survive as a saprophyte for up to 15 years in the soil [1]. It has a wide host range including crop plants namely mungbean, sesame, maize, chickpea, cowpea, sunflower, sorghum, cotton, peanut [2]–[4], and forest trees including Pinus, Abies, Cassia, Pseudotsuga [5],[6]. It causes dry root rot, charcoal rot, dry weather wilt, seedling blight disease and ashy stem blight in susceptible hosts [7]. It is a soil-borne fungus that survives mainly as microsclerotia that act as primary inoculum and repeatedly germinate during the whole season of the crop. These microsclerotia are produced in root as well as stem tissues of host plants However, in many crops such soybean, this fungus is also seed-borne [8]. Cloncurry buffel grass Cenchrus pennisetiformis) is a summer growing perennial grass of family Poaceae. It is palatable plant species with good forage quality and used for cattle grazing. Arshad Javaid is with Institute of Agricultural Sciences, University of the Punjab, Lahore, Pakistan (Phone: +92 42 99231846, Fax: +92 42 99231187, * e-mail: arshadjpk@yahoo.com) In Punjab, Pakistan it generally grows along the road sides. The weed is known to have antifungal and herbicidal potential [9],[10]. The present study was therefore carried out to assess the antifungal activity of this grass for the management of M. phaseolina II. MATERIALS AND METHODS A. Isolation and Identification of Fungal Pathogen Stem portions of the cowpea plants suffering from charcoal rot disease were surface sterilized with 1% sodium hypochlorite, thoroughly rinsed sterilized water, dried plated on malt extract agar medium under aseptic conditions. The plates were incubated at 28 o C in the dark for one week. The isolated fungal pathogen was purified and sub-cultured. The isolated fungus was identified as M. phaseolina on the basis of characteristic black-coloured oblong microsclerotia [11]. B. Screening Bioassays Dried shoot (leaves+stem), root and inflorescence of C. pennisetiformis were thoroughly grinded to fine powders. These powdered plant samples were soaked at 150 g L -1 of the methanol in air tight jars separately for 7 days room temperature. Afterwards extracts were obtained from soaked materials by filtering through an autoclaved muslin cloth followed by filter papers and preserved in plastic bottles. The leftover plant materials were again soaked in 500 mL methanol, filtered and preserved in plastic bottles. Filtrates were combined and evaporated in a rotary evaporator under vacuum. Crude methanolic extracts (8.4 g) of each of the three different parts of the grass were dissolved in 2 mL of dimethyl sulphoxide (DMSO) and raised the volume to 14 mL stock solution by adding sterilized distilled water. Separately a mixture of DMSO in water (2 mL DMSO + 12 mL H 2 O) was prepared to keep the quantity of DMSO constant in different treatments. Seventy six milliliters malt extract broth was autoclaved at 121 o C for 30 minutes in 250 mL conical flasks and cooled at room temperature. In order to avoid bacterial contamination, chloromycetin at 50 mg 100 mL -1 of the medium was also added. Six concentrations (0.5, 1.0, 1.5, 2.0, 2.5 and 3.0 g 100 mL -1 ) were prepared by adding 0.67, 1.332, 1.998, 2.664, 3.33 and 3.99 mL stock solution and 3.33, 2.668, 2.002, 1.336, 0.67 and 0.01 mL mixture of DMSO in water , respectively, to each flask containing 76 mL autoclaved malt extract broth. The 80 mL of each treatment was divided into four equal portions in 100 mL conical flasks to serve as replicates. Control treatment was prepared by addition of 4 mL DMSO + distilled water mixture to 76 mL of the growth medium. Evaluation of Antifungal Potential of Cenchrus pennisetiformis for the Management of Macrophomina phaseolina Arshad Javaid, Syeda F. Naqvi M World Academy of Science, Engineering and Technology International Journal of Biotechnology and Bioengineering Vol:6, No:9, 2012 761 International Scholarly and Scientific Research & Innovation 6(9) 2012 scholar.waset.org/1307-6892/13427 International Science Index, Biotechnology and Bioengineering Vol:6, No:9, 2012 waset.org/Publication/13427