We evaluated the herbicidal potential of Argemone mexicana extracts against Ageratum conyzoides, a problematic agricultural weed. Aqueous extracts were prepared from driedA. mexicana plant material and tested at concentrations of 10,50,100 and 200 mg/ml. Laboratory bioassays assessed seed germination, seedling growth, biomass accumulation, photosynthetic pigments and protein content. Bioactive compounds were identified using GC-MS analysis. Field trials evaluated weed control efficacy under natural conditions using a randomized complete block design. Extract significantly reduced seed germination from 83.33 % (control) to 20.0 % at 200 mg/mL (p <0.001). Seedling growth, biomass, chlorophyll content and protein levels decreased proportionally with extract concentration. Complete plant mortality occurred at the highest concentration. GC-MS analysis identified 23 bioactive compounds, primarily alkaloids (protopine, sanguinarine and berberine) and phenolic acids (caffeic acid and ferulic acid). Field trials demonstrated 96.5 % weed control efficacy at 200 mg/mL within 7-days, comparable to synthetic herbicides. A. mexicana extracts exhibited herbicidal activity through multi-compound synergistic effects. While promising for bioherbicide development, practical application requires addressing concentration requirements, cost-effectiveness and broader spectrum validation. The findings support the continued research into plant-derived herbicides as sustainable alternatives for weed management.
Samal et al. (Wed,) studied this question.