Emerging biological agents for crop protection: broadening the biocontrol toolbox
Biocontrol is increasingly central to sustainable agriculture, offering a toolbox of living agents that protect crops with fewer environmental downsides than conventional pesticides. As climate change reshapes pest pressures and regulatory moves push for safer inputs, scientists are expanding the repertoire beyond traditional biopesticides. This article surveys emerging biological agents and how they broaden the biocontrol toolbox, with attention to mechanisms, safety, policy, and practical integration for farmers.
Biocontrol toolbox expansion: beauveria bassiana, metarhizium anisopliae, and integration
Two widely used fungi now sit at the forefront of expanding biocontrol options: Beauveria bassiana and Metarhizium anisopliae. Both are entomopathogenic fungi, meaning they infect and kill insects, but they differ in host preferences, environmental tolerance, and formulation opportunities. B. bassiana spores adhere to an insect’s cuticle, germinate, and deploy enzymes and toxins that breach the exterior barrier, eventually leading to death. M. anisopliae follows a similar route but can excel under different humidity and temperature regimes. Together, they offer broad pest control potential across aphids, whiteflies, beetles, caterpillars, and soil-dwelling pests, with strain choice enabling tailoring to local crops and pests.
Beyond direct mortality, these fungi can behave as endophytes in some plant species, living inside plant tissues without causing disease. This endophytism can bolster plant defenses and alter herbivore behavior by making the plant less palatable or less suitable for feeding. Such multifaceted action—direct infection plus indirect plant-mediated effects—supports integration into broader pest-management programs and can reduce reliance on chemical sprays. Product forms range from wettable powders and oil-based formulations to granular coatings, each designed to protect spores from ultraviolet light and to optimize delivery to target pests. The result is a more adaptable, seasonally responsive approach to crop protection, aligned with the goals of integrated pest management.
Beauveria bassiana and Metarhizium anisopliae: modes of action and pest targets
The success of these fungi lies in their modes of action and the ecological context of their use. Infection begins with spore contact, followed by germination and enzymatic digestion of the insect cuticle. Physical pressure from hyphal growth and toxins contribute to mortality, while environmental factors such as humidity and temperature influence infection efficiency. Because these agents rely on direct contact, coverage and timing are critical: spray wells during pest activity windows, ensure adequate droplet spread, and avoid conditions that rapidly degrade viability.
A key advantage is their versatility across pest complexes, especially in greenhouse and field settings. Some strains are more effective against soft-bodied pests, others against chewing insects; ongoing screening and local testing help match the right strain to the crop, pest, and region. In addition, plant-associated benefits—where endophytic colonization modulates plant physiology—may complement direct pest suppression, potentially reducing the need for multiple sprays. This flexibility is central to adoption, as growers seek tools that work with their existing cultural practices and environmental constraints.
Baculoviruses and crop protection: host specificity, application, and integration into crop protection programs
Baculoviruses, particularly nucleopolyhedroviruses (NPVs) and granuloviruses (GVs), represent a different branch of biological control. They are highly host-specific, infecting only particular pest species or closely related groups. This specificity minimizes non-target effects and often aligns with regulatory expectations for safety. In practice, baculoviruses are ingested by larval stages and then replicate within the insect, disrupting development and leading to death over days. The trade-off is a relatively slow kill compared with some chemical insecticides, but the precision helps preserve natural enemies and pollinators and reduces residues in harvested crops.
Field deployment relies on stable formulations and timely applications to align with vulnerable life stages of the pest. Advances in production—such as scalable fermentation and optimized formulations that protect viral particles from UV light—have improved field performance and shelf life. When integrated with pheromone traps, monitoring, and selective use of other control measures, baculoviruses can form a backbone of targeted, low-impact pest management within an IPM framework. Their compatibility with plant health programs and resistance management strategies makes them a valuable component of the broader toolbox.
Biosafety in the deployment of emerging biocontrol agents
Any new biological control product must pass rigorous biosafety evaluations. The strength of biocontrol lies in its safety profile: many agents have narrow host ranges and limited environmental persistence, reducing risks to humans, domestic animals, and beneficial insects when properly managed. Nevertheless, careful assessment of non-target effects, ecological interactions, and potential for horizontal gene transfer remains essential. Field trials, open-environment monitoring, and robust quality control during production help ensure that products perform as intended without unintended consequences. Transparent communication with growers and communities about how these agents work and their safety profiles is a cornerstone of responsible biosafety practice.
Regulatory considerations for field release and risk assessment for biocontrol agents
Regulatory frameworks guide the safe, effective, and timely deployment of biocontrol agents. They typically require data on efficacy under realistic conditions, host specificity, environmental fate, and any potential non-target impacts. Standards for manufacturing, formulation stability, and quality control must be met, often under good manufacturing practice (GMP) guidelines. Streamlined but rigorous risk assessment processes are increasingly emphasized to avoid unnecessary barriers while protecting ecosystems. Harmonization across regions can speed adoption by reducing duplicative testing, provided safety remains the anchor. For farmers, clear labeling, label-restriction guidance, and post-market surveillance are essential elements that bolster confidence and facilitate practical use.
Integration with conventional IPM: monitoring, resistance management, and adoption
The most successful biocontrol programs integrate multiple agents with cultural practices, pheromone-based monitoring, and judicious use of conventional pesticides. Integration planning includes selecting compatible products, staggering applications to avoid antagonism, and establishing monitoring protocols to detect early pest buildup or shifts in pest communities. Resistance management, long a cornerstone of chemical control, applies here as well: rotating modes of attack, combining fungi with viruses, and reserving high-toxicity inputs for emergency use can slow adaptation by pests. Farmers benefit from decision-support tools that translate pest threshold data, weather forecasts, and product performance into actionable spray schedules. Ultimately, integration aims to maintain ecosystem balance, protect crop yield and quality, and reduce environmental footprints.
Future directions for expanding the biocontrol toolbox
Researchers are advancing the biocontrol toolbox through strain refinement, formulation science, and ecosystem-based strategies. Discoveries in plant–microbe interactions open possibilities for inoculating crops with endophytic strains that confer systemic resistance. Microbial consortia—carefully matched communities of fungi, viruses, and bacteria—hold promise for synergistic protection across pest types. Technology-driven improvements in delivery systems, such as encapsulation and targeted release, can extend shelf life and field performance. As regulatory landscapes evolve toward harmonization and practical registration pathways, widespread farmer adoption becomes more feasible. The result is a more resilient, environmentally conscious approach to protecting crops from evolving pest pressures, with a toolbox that blends precision, sustainability, and real-world practicality.
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Bachelor's degree in ecology and environmental protection, Dnipro State Agrarian and Economic University
