Biocontrol Agents for Sustainable Management of Plant Pathogens: A Review

Biocontrol agents have gained global importance as sustainable solutions for managing plant pathogens while reducing reliance on synthetic pesticides that pose risks to human health, biodiversity, and environmental safety. This review aims to explore biocontrol agents for sustainable management of plant pathogens. This review synthesises advances in the use of microbial antagonists such as Trichoderma spp., Pseudomonas fluorescens, Bacillus subtilis, Streptomyces spp., mycorrhizal fungi, and viral and nematophagous organisms in the suppression of fungal, bacterial, viral, and nematode diseases. The mechanisms of action include antibiosis, nutrient competition, parasitism, predation, enzyme secretion, and induction of systemic resistance, supported by omics-based insights into microbial–pathogen–plant interactions. Application strategies range from seed treatment, soil amendments, and foliar sprays to post-harvest bioprotection, with formulation innovations such as nano-encapsulation and bio-priming improving field stability and efficacy. Case studies demonstrate significant disease suppression and yield enhancement, such as 55–70% reduction in tomato wilt with Trichoderma, 60% suppression of take-all in wheat with Pseudomonas fluorescens, and 70% control of fire blight in apple through phage therapy. Despite these successes, challenges persist in achieving consistent field performance due to environmental variability, short shelf life, and complex regulatory pathways. Recent research emphasises the development of climate-resilient strains, the exploration of endophytes and novel microbes, and the deployment of digital tools and artificial intelligence for predictive disease management. Global market trends project biocontrol adoption to reach USD 13.7 billion by 2027, driven by consumer demand for residue-free produce, policy support for organic farming, and IPM integration. The review highlights that scaling adoption requires farmer awareness programs, harmonised regulations, and public–private investment to overcome commercialisation barriers. Biocontrol agents represent a cornerstone for climate-smart and ecologically balanced agriculture, offering long-term benefits for food security, environmental health, and sustainable intensification of crop production systems. Biocontrol agents have emerged as vital tools in sustainable agriculture by offering effective, eco-friendly alternatives to synthetic pesticides while addressing the global challenges of crop losses, food security, and environmental degradation. Strengthened policies, extension efforts, and global commercialisation will be crucial to unlocking its full potential.