Biological control strategies as sustainable alternatives to herbicides in weed management

Herbicides remain the dominant tools for weed control because of their cost effectiveness and selectivity, yet prolonged and intensive use has raised concern regarding soil degradation, disruption of microbial communities, non-target effects, and the rapid emergence of herbicide resistance. This research synthesizes evidence on the ecological impacts of herbicides and evaluates biological control strategies as sustainable and complementary alternatives within integrated weed management. A PRISMA-ScR guided literature review identified 108 peer reviewed studies published between 2000 and 2025 from Scopus, PubMed, ScienceDirect and SpringerLink, with selective inclusion of foundational literature capturing early biological weed control research. Evidence indicates that herbicides alter soil microbial biomass, enzyme activity, and community composition, with outcomes dependent on herbicide class, application rate, soil properties, and environmental context. Glyphosate and atrazine suppress sensitive microbial taxa while enriching specialized degraders, reflecting ecological disruption and microbial adaptation. Fungal communities, particularly arbuscular mycorrhizal fungi, are consistently vulnerable, leading to reduced nutrient acquisition and weakened plant resilience. Herbicide resistance continues to expand globally, undermining long term chemical efficacy. Biological control strategies, including microbial agents such as Trichoderma and Bacillus, insect herbivores, grazing animals, allelopathic crops, bioherbicides, compost and biochar, demonstrate diverse mechanisms of weed suppression and soil restoration across agroecosystems. These approaches enhance crop competitiveness and stimulate beneficial microbial functions, although field performance is constrained by environmental variability, formulation stability, regulatory barriers, and limited extension support. The findings emphasize the need for integrative and sound weed management. © 2026 Elsevier B.V.