CONSIDERATIONS IN USING COCCINELLIDS FOR BIOLOGICAL CONTROL OF APHIDS

Authors: Elliott, Norman - Norm; OBRYCKI, J - OKLAHOMA STATE UNIV; GILES, K - IOWA STATE UNIVERSITY

Submitted to: International Organization of Biocontrol & Experiment Station Symposium
Publication Type: Proceedings
Publication Acceptance Date: 7/15/2001
Publication Date: 8/1/2001
Citation: Elliott, N.C., Obrycki, J.J., Giles, K.L. 2001. Considerations in using coccinellids for biological control of aphids. Proceedings of the International Organization of Biocontrol, August 2-5, 2001, Bozeman, Montana. p. 13.

Interpretive Summary: During the twentieth century, predators that feed on many different types of prey (called generalist predators) have frequently been imported into the United States for biological control of insect pests of agriculture, horticulture, and forestry. Although there have been positive effects resulting from importation and establishment of generalist predators, primarily a reduction in the economic impact of pest insects, there have also been unintended negative effects. We survey the types of negative effects that can occur, and discuss the potential for such effects. We focus primarily on lady beetles that prey on aphids because several studies have been done on imported lady beetles that document their negative impacts. The potentially serious effects that have been documented include preying on rare or endangered native insects, and competing with or preying on native natural enemies. However, even for lady beetles, effects on native insects have usually only been superficially studied. Detailed studies are needed to address questions about the benefits and risks of importing lady beetles and other generalist predators into the United States for biological control. Native lady beetles and other natural enemies are important for naturally occurring biological control, and more detailed understanding of their ecology would be beneficial in determining the rewards and risks of importing generalist predators from foreign lands to control insect pests in the United States.

Technical Abstract: During the twentieth century, generalist predators have frequently been imported for classical biological control of pest arthropods. We discuss potential unanticipated negative effects of established generalist predators. We focus primarily on aphidophagous Coccinellidae because some studies have been completed documenting their negative impacts. Documented unanticipated effects include predation on non-pest arthropods, particularly those of conservation concern, and competing with or preying on other natural enemies. However, even in this group of predators, effects on resident pest and predator populations, and on the broader community, have usually only been superficial. Long-term quantitative studies are needed to address questions about the benefits and risks of importing Coccinellidae and other general predators. To understand the potential non-target effects, greater research emphasis is needed on generalist predators in their native ranges, predator habitat specificity, colonization and use of non-agricultural environments, and assessment of community-level interactions. Coccinellidae and other general predators are a major component of naturally occurring and human-assisted aphid biological control, however, detailed understanding of their ecology, apart from direct predator-prey interactions on target pests, and their role in structuring communities is absent for virtually all species.