Allelochemicals as Bioherbicide: Potentials, Applications and Future Perspectives

Repeated herbicide use and herbicide resistance have increased interest in allelochemicals for weed management. This narrative review synthesizes published evidence on mechanisms of action, major compound classes, agricultural applications and barriers to bioherbicide development. Allelochemicals can inhibit germination and seedling growth through effects on membrane integrity, cell division, photosynthesis, hormonal signaling and oxidative balance. Phenolics, benzoxazinoids, sorgoleone and terpenoids offer different opportunities for crop breeding, residue management and formulation development. Laboratory activity does not establish field efficacy or crop selectivity. Soil adsorption, microbial transformation, environmental instability, dose variability and non-target effects constrain application. Cover crops and mulches combine chemical interference with physical weed suppression, so their performance cannot be attributed to allelopathy alone. Allelochemicals offer useful components of integrated weed management, but reliable deployment requires standardized formulations and replicated field validation of efficacy, crop safety, environmental fate and economic feasibility.