INTRODUCTION Cogongrass [Imperata cylindrica (L.) Beauv.] is a problematic weed of the tropical region that has invaded over 500 million ha worldwide and causes significant losses both in cultivated and non-cultivated areas (MacDonald 2007; Mohamad et al., 2011). About 62-90% reduction in yield of different crops have been documented due to this weed (Koch et al., 1990; Avav, 2000; Chikoye et al., 2001). Once established, it is extremely competitive with crops and neighboring plant communities (Koger and Bryson, 2004). The grass is known to exhibit strong allelopathic activity against many crops, weeds and forest tree species (Hussain and Abidi, 1991; Cerdeira et al., 2012. Anjum et al. (2005) has reported that I. cylindrica can limits the spread of Parthenium hysterophorus possibly through its allelopathic exudates. Various secondary metabolites particularly phenolic compounds in foliage, roots and rhizomes of this grass are responsible for strong allelopathic activity and contribute to its extreme invasiveness and competitiveness (Koger and Bryson, 2004). Many recent studies have shown that allelopathy can be used for the management of pests and diseases (Farooq et al., 2011; Javaid and Shoaib, 2012). The allelopathic potential of I. cylindrica may be exploited as effective tool for the management of phytopathogens. Few earlier studies have shown that aqueous extracts and root exudates of this grass suppress root colonization by mycorrhizal fungi (Afzal et al., 2000; Javaid, 2008). In addition, Bajwa et al. (2002) and Shafique et al. (2004) reported pronounced antifungal activity of shoot and root extracts of this grass against Fusarium spp. Macrophomina phaseolina is an important soil-borne phytopathogen, has a wide geographic distribution, causes diseases in about 500 plant species and can survive for up to 15 years in the soil as a saprophyte (Indera et al., 1986; Kaur et al., 2012). It survives in the soil mainly as microsclerotia that germinate repeatedly during the crop-growing season (Gupta et al., 2012). In Pakistan, 67 economic hosts of M. phaseolina including sunflower, cotton, rice, maize, cucurbits, mungbean, okra, and wheat have been reported (Shehzad et al., 1988; Javaid and Amin, 2009; Javaid and Saddique, 2011). Diseases caused by M. phaseolina are responsible for massive yield losses in crops (Kaur et al., 2012), which demand necessary economic friendly control measures. Earlier studies have shown that crude extracts of some allelopathic plants such as Datura metel, Chenopodium album and C. murale, as well as purified compounds from mango leaves can effectively control growth of M. phaseolina (Javaid and Amin, 2009; Kanwal et al., 2010; Javaid and Saddique, 2012). However, studies regarding the use of extracts of I. cylindrica for management of M. phaseolina are entirely lacking. The present research work was, therefore, carried out to assess the antifungal potential of methanolic extracts of different parts of I. cylindrica against M. phaseolina. Pak. J. Agri. Sci., Vol. 52(1), 37-41; 2015 ISSN (Print) 0552-9034, ISSN (Online) 2076-0906 http://www.pakjas.com.pk MANAGEMENT OF Macrophomina phaseolina BY EXTRACTS OF AN ALLELOPATHIC GRASS Imperata cylindrica Arshad Javaid 1,* , Syeda Fakehha Naqvi 1 , Amna Shoaib 1 and Sheikh Muhammad Iqbal 2 1 Institute of Agricultural Sciences, University of the Punjab, Lahore, Pakistan. 2 National Agriculture Research Center, Islamabad, Pakistan. * Corresponding author’s e-mail: arshadjpk@yahoo.com 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. Keywords: Antifungal activity, Imperata cylindrica, Macrophomina phaseolina, natural fungicides