Biocontrol

Biocontrol, or biological pest control, is the management of pest populations using living organisms. It seeks to suppress pests to acceptable levels while reducing reliance on chemical pesticides. Biocontrol can be applied alone or as part of integrated pest management and is influenced by ecological relationships between pests, their natural enemies, and the environment.

Agents include predators, parasitoids, and pathogens. Predators such as lady beetles and lacewings feed on pest insects; parasitoids lay their eggs in or on pests, killing them; pathogens such as fungi and bacteria infect and kill pests. Classic examples include Rodolia cardinalis, released in the 1880s to control cottony cushion scale in California citrus, and Cotesia glomerata, released to suppress caterpillars of the cabbage white butterfly. Microbial agents such as Bacillus thuringiensis and Beauveria bassiana are used as biopesticides. Biocontrol also encompasses conservation and augmentation strategies that boost or supplement natural enemy populations.

Approaches include classical or importation biocontrol (establishing natural enemies in new areas), augmentation (releasing additional enemies on a schedule or in large numbers), and conservation (protecting and enhancing habitats to support native beneficial species). Biocontrol is used in agriculture, forestry, urban pest management, and, in some cases, invasive plant control.

Advantages include lower chemical inputs, potential for long-term suppression, and compatibility with other IPM practices. Limitations include uneven establishment, delayed effects, potential non-target impacts, and the need for regulatory approval and monitoring. Biocontrol outcomes are context dependent and not universally reliable.

Globally, biocontrol is widely employed with ongoing research into risk assessment, host-range testing, and monitoring to minimize ecological risks and maximize effectiveness.