Harnessing Biocontrol Agents for Weed Management: A Sustainable Approach

Abstract

Weed infestation remains a major constraint to sustainable crop production and ecosystem management because weeds compete with cultivated and native plants for water, nutrients, light and space. Conventional weed control methods, particularly repeated herbicide use, can contribute to environmental contamination, residue concerns, non-target effects and the development of herbicide resistance. Biological control offers an alternative approach by using living organisms or naturally derived agents to suppress weed growth, reproduction and spread. This review summarises the role of different biocontrol agents, including insects, fungi, bacteria, viruses and nematodes, in the management of terrestrial and aquatic weeds. Classical biological control, augmentation, bioherbicide use and the application of natural enemies are discussed with examples involving major invasive weeds such as parthenium, water hyacinth, lantana, saltcedar, purple loosestrife, prickly pear, St. Johnswort and salvinia. Microbial agents, especially fungal pathogens and selected bacterial strains, are also considered for their potential to provide host-specific weed suppression. The manuscript further highlights the emerging but still limited role of nematodes in weed management. Although biological control can reduce dependence on synthetic herbicides and support integrated weed management, its performance depends on host specificity, environmental conditions, agent establishment, formulation stability and ecological safety. The review emphasises that biocontrol should be used as one component of an integrated weed management strategy rather than as a complete replacement for other control methods. Further research is needed to improve field reliability, ecological risk assessment, formulation development and large-scale deployment of biocontrol agents for sustainable weed management.