Bridging the Lab-Field Gap: Towards Scalable Biocontrol Applications for Sustainable Maize Protection

Biological control agents (BCAs) have emerged as a key strategy to mitigate maize diseases while reducing dependence on synthetic agrochemicals, which pose risks to human health, ecosystems, and microbial diversity. This review synthesizes advances from 63 research articles published between 2020 and 2025, selected through a Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) approach to capture studies with in vitro, greenhouse, or field validation. The analysis highlights major fungal and bacterial threats to maize production and evaluates BCAs, including Bacillus, Trichoderma, Streptomyces, and entomopathogenic or endophytic microorganisms, tested across multiple experimental levels. Results show that many agents demonstrate strong antagonism under controlled conditions, promoting plant growth, reducing pathogen incidence, and lowering mycotoxin contamination. Field trials, however, reveal inconsistent performance due to environmental variability, formulation instability, and incomplete understanding of strain-specific mechanisms. Emerging approaches such as microbial consortia, metabolite-based biocontrol, biochar–microbe combinations, and evaluations under dual-stress conditions offer promising avenues to improve reliability and expand applicability. Overall, the review underscores that although microbial biocontrol holds substantial potential for sustainable maize protection, progress toward scalable implementation requires integrating omics-based characterization, optimized formulations, genotype-specific evaluations, and multi-season field trials to bridge the gap between laboratory efficacy and field performance.