Norazua Zakaria, Afiq Aiman Saharudin, Mst. Motmainna, Mahmudul Hasan
Weeds pose a serious threat to crops, causing greater yield losses than any other pest. Synthetic herbicides are potential tools for weed management, but their increasing and often indiscriminate use has caused human health problems, environmental pollution, herbicide resistance, and so on. Allelopathy-based bioherbicides offer more sustainable alternatives to synthetic herbicides for weed management that could be integrated into weed management strategies to reduce herbicide reliance. This systematic review, guided by PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses), aimed to synthesize current evidence on allelochemicals and their potential for bioherbicide development. A comprehensive search of Web of Science, Scopus, PubMed, and Google Scholar identified 112 studies meeting the inclusion criteria. The review covers synthetic herbicides for weed control, allelochemicals, bioherbicides development, currently available bioherbicides in the market and their impact on weed control and physiology, and potential factors influencing allelochemical efficacy. Allelochemicals impair weed growth through reduced nutrient uptake, reduced pigment synthesis, and alterations in stress-related hormones and reactive oxygen species accumulation. Several allelopathic species and their potential allelochemicals are highlighted as promising candidates for bioherbicide development, though variability in field efficacy and limited large-scale validation remain key limitations. Future research should focus on standardizing extraction and application methods and validating efficacy under field conditions. Clarifying the gene regulatory mechanisms underlying allelochemical biosynthesis and release will also be an important direction for future work. Overall, allelopathy-based bioherbicides represent a promising, sustainable tool for integrated weed management, though further mechanistic and applied research is needed before commercial adoption.