Classical Insect Biocontrol in North America, 1985 to 2018: A Pest Control Strategy that is Dying Out

Authors: VAN DRIESCHE, ROY - University Of Massachusetts, Amherst; WINSTON, RACHEL - Mia Consulting, Llc; Duan, Jian

Submitted to: CAB Reviews: Perspectives in Agriculture, Veterinary Science, Nutrition and Natural Resources
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 5/11/2020
Publication Date: 5/14/2020
Citation: Van Driesche, R., Winston, R.L., Duan, J.J. 2020. Classical Insect Biocontrol in North America, 1985 to 2018: A Pest Control Strategy that is Dying Out. CAB Reviews: Perspectives in Agriculture, Veterinary Science, Nutrition and Natural Resources. 15: 1-9. https://doi.org/10.1079/PAVSNNR202015037.
DOI: https://doi.org/10.1079/PAVSNNR202015037

Interpretive Summary: Classical biocontrol through introduction and establishment of natural enemies (parasitic wasps and insect predators) is a sustainable pest management technology. This pest control technology has been effectively used against many species of invasive insect pests in agriculture, forests and natural ecosystems with little adverse effect on human health or the environment. We examined the releases of natural enemies for classical biocontrol of invasive insects since 1985 in Canada, Mexico, the continental USA, and U.S. overseas areas and extracted trends in usage and success. We found that the number of natural enemy introductions in North America for classical control of insect pests since 1985 has declined significantly. Pest invasions since 1985, however, have continued, affecting North American agriculture, forests, and natural ecosystems, likely due to expansions of international travel and trade. Considering its sustainability, effectiveness, and minimum adverse effects on human health and environment, we recommend that relevant government agencies and institutions review the regulatory and/or funding framework, within which classical biocontrol acts so that its application can continue to be a feasible management option for invasive insects.

Technical Abstract: This review is an analysis of a new catalog on the use of classical biological control of arthropods in North America since 1985 (Van Driesche et al., 2018). Based on this new catalog, we reviewed trends in the release since 1985 of exotic parasitoids and predaceous insects for classical biocontrol of invasive insects in Canada, Mexico, the continental USA, and U.S. overseas areas. Trends measured included numbers of agents released, numbers established, numbers having a positive impact on the target pests, and numbers of projects initiated, which allow readers to determine if use of this method of insect control has increased, declined, or held steady between 1985 and 2018. These trends provide understanding of the social relationship between countries and this form of pest control and how it has changed over time. During this period, there were 208 parasitoid releases (= species x country or overseas U.S. area) compared to 29 for predators. Of these parasitoid releases, 112 (53.8%) resulted in the agent’s establishment, and approximately 50% of the established agents (57) were credited with controlling the target pest partially or completely. Most releases occurred in the USA, and we calculated trends for parasitoids per 5-year period. From 1985 to 2018, numbers of parasitoids released (counting the continental USA, Hawaii, Puerto Rico, Guam, Marianna Islands, and the U.S. Virgin Islands separately) declined per 5-year interval from 52 to 7, an 86.5% reduction. The percentage of newly released parasitoids that established increased from 42 to 71%, a 1.7-fold increase, but the number of newly established parasitoid species that reduced their target pests declined from 73 to 40%. Also, the number of new projects initiated per 5-year period decreased from 31 to 5, an 84% decrease. The percentage of projects reducing their target pests showed no strong trend: 1985–1989, 42% vs. 2010–2014, 60%. At the agent level, chalcidoids were most effective: of 119 chalcidoid releases, 76 (63.9%) established, and 45 (37.8%) reduced their target pests. However, chalcidoids (based on available literature host records) were not more specific than less effective groups, despite the view that higher efficacy would be associated with greater host-specificity. The predominance of chalcidoids is likely due to their frequent use against scales, whiteflies, mealybugs, aphids, and psyllids, which are tightly associated with live plants, tend to be moved frequently internationally, and often become agricultural pests in areas where they are introduced.