MANAGEMENT OF SOME PROBLEMATIC WEEDS OF WHEAT BY METABOLITES OF Drechslera sp. PREPARED IN MALT EXTRACT MEDIUM

Present study was designed to evaluate the herbicidal activity of metabolites of four Drechslera species viz. D. australiensis, D. hawaiiensis, D. biseptata and D. holmii (prepared in malt extract broth) against some problematic weeds of wheat namely Rumex dentatus, Phalaris minor and Avena fatua in 2009. Metabolites of Drechslera spp. were employed in 100% (original) and 50% concentrations. These metabolites wrought appreciable reduction in the germination of test weed’s seeds by 3-72%. Original metabolites of all the fungal species significantly reduced shoot length and biomass by 39-72% and 30-70%, respectively. Metabolites of D. australiensis D. hawaiiensis and D. biseptata showedpronounced phytotoxic activity against all tested weeds, D. holmii appeared to be least effective. Root growth was more susceptible to metabolites than shoot growth. The metabolites of Drechslera spp. reduced 56-97% and 27-92% in root and shoot biomass, respectively. The present study concludes that metabolites of all the tested Drechslera spp. contain phytotoxic constituents that can be used as benign method of weed control alternative to synthetic chemical herbicides for management of some weeds of wheat. Further studies regarding the isolation of effective ingredients are in progress.