POTENTIAL OF NAPIER GRASS (PENNISETUM PURPUREUM SCHUMACH.) EXTRACTS AS A NATURAL HERBICIDE

The present study was undertaken to investigate the herbicidal potential of aqueous and methanolic extracts of culm plus leaves and root of Pennisetum purpureum against two selected weed species; Hedyotis verticillata and Leptochloa chinensis under laboratory and glasshouse conditions. Extracts in different solvents and plant tissues exhibited markedly variable herbicidal activities against the target weed species. Methanolic and aqueous extracts of culm plus leaves inhibited germination of L. chinensis by 50% at a concentration of as low as 0.07 and 0.47g/L, respectively. Radicle growth of L. chinensis was strongly suppressed by aqueous root extract. Methanolic extract of culm plus leaves were proven highly phytotoxic to H. verticillata where green colour of the leaf disc was reduced by 50% at a concentration less than 0.1g/L. Aqueous root extracts at 150g/L concentration strongly inhibited seedling growth H. verticillata but less inhibition was provided by methanolic root extracts at this concentration. The results of this study suggest that P. purpureum extracts can be used as natural herbicide for weed management.