Unlocking the allelopathic and phytotoxic potential of indigenous bio-herbicide weeds (Withania coagulans and Achyranthes aspera) against Staple Crops

The dual-use potential of medicinal weeds as both therapeutic agents and natural bio-herbicides has gained increasing attention in sustainable agriculture. This study examines the allelopathic effects of aqueous leaf extracts from two indigenous medicinal weeds, With Ania coagulants and Achyranthes aspera, on the early growth of three major staple crops: wheat (Triticum aestivum), rice (Oryza sativa), and maize (Zea mays). Conducted under controlled laboratory conditions at the University of Agriculture in Faisalabad, the experiment assessed germination percentage, root and shoot length, seedling dry weight, and seedling vigor index across extract concentrations of 5%, 10%, 15%, and 20%. The results showed a clear dose-dependent phytotoxic response in all crops, with A. aspera consistently demonstrating more potent inhibitory effects than W. coagulants. Significant reductions were seen in germination (up to 64%), root elongation (over 50%), biomass (up to 42%), and seedling vigor index (more than 50%) at the highest extract concentrations, especially in maize and wheat. Pearson correlation analysis revealed strong negative correlations (r > –0.9) between extract concentration and all measured growth parameters, reinforcing the allelopathic potential of these species. Visual observations further supported biochemical interference through symptoms like root browning and reduced lateral emergence. These findings highlight the potential of W. coagulants and A. aspera as eco-friendly, locally available candidates for bio-herbicide development. Their integration into Integrated Weed Management (IWM) strategies could decrease reliance on synthetic herbicides, promote agroecological sustainability, and help combat herbicide resistance in intensive cropping systems.