Evaluation of Allelopathic Potential of Plant Extracts Against Common Weed Species Under Vivo Conditions

Abstract Weeds severely threaten crop productivity by competing for essential growth resources, while increasing herbicide resistance and environmental risks associated with synthetic chemicals necessitate eco-friendly alternatives. This study evaluated the allelopathic potential of different plant-based extracts, including Walnut (Juglans nigra) bark, Sugarcane (Saccharum officinarum) bagasse, Parthenium (Parthenium hysterophorus) solution, Tumha (Citrullus colocynthis), Algal water extract, Phalaris minor leaves extract, Vinegar, and Tap water (control), against six problematic weed species: Phalaris minor, Melilotus indicus, Cirsium discolor, Cucumis pubescens, Cyperus rotundus, and Convolvulus arvensis. Experiments were conducted under vivo conditions in a completely randomized design with five replications. Results revealed that Walnut bark, Algal water, and Vinegar exhibited the strongest inhibitory effects on seed germination, germination energy, chlorophyll content, shoot and root growth, and overall biomass accumulation. Field thistle and Cucumis were the most sensitive species, showing minimum germination (0.30–0.53), whereas Phalaris minor showed the highest tolerance with maximum germination (79.25%) and biomass accumulation. Sugarcane bagasse and Parthenium demonstrated moderate suppression, while Phalaris minor extract showed limited autotoxic effect on its own species. Overall findings confirm that plant-derived allelopathic extracts, particularly Walnut bark, Algal water, and Vinegar, possess strong bioherbicidal potential and may serve as sustainable weed management alternatives; however, higher concentrations or combined strategies are required for highly resistant weeds such as Phalaris minor and Cyperus rotundus. Moreover, further investigation and integration with reduce herbicides will help in noxious weeds management practices.