Biological control models

The first section of this article introduces the broad types of general population models before specific biological control models are explored. Both types of models help develop theoretical understanding of the functioning of predator'prey, parasitoid'host, or pathogen'host interactions but the emphasis of specific models is often on utility: how best to practice biological control. The majority of the specific models relate to classical biological control programs, though, in the realm of arthropod control, models are also used for inundative, augmentative, and inoculative biological control. Very little use of models has been evident for conservation biological control. The types of questions that specific models have been used for include predicting the likely success of release, identifying optimal agents, assessing the risks of a planned program, and understanding why a program has failed. Model-derived answers can be compared for alternative biological control approaches and for candidate agent species so that appropriate choices in methods can be made. More fundamentally, as models help refine our knowledge of the population dynamics that apply in biological control systems, our theoretical understanding of the ecology is improved. Progress in both the applied and theoretical domains offers scope to make biological control less hit-and-miss with consequent cost savings and reduced risk of environmental impact.