Some pesticides effect deleterious changes to more than one biochemical process in the target pest. These pesticides are, therefore, designated “multi-site” pesticides. Other pesticides work to disrupt a specific biochemical process in a pest and these are designated “single-site” pesticides.

The major benefit of single-site pesticides is that they are typically much safer for the environment, the ecosystem and the product-user compared to multi-site pesticides, since they are not toxic to non-target species. Therefore, most single-site pesticides are typically classified as low risk pesticides, whereas multi-site pesticides are typically classified as high risk pesticides. (Risk in this case refers to risk to non-target organisms, humans, etc.—not the development of pesticide resistance.)

The downside of single-site pesticides is that they are prone to the development of resistance among pest populations. Multi-site pesticides, on the other hand, are generally not prone to resistance development.

1. Benbrook, C., Mellinger, C., Sexon, D., Stevenson, W., Wyman, J. 2003. Use of “resistance risk profiles” to guide resistance management planning. Pesticide Outlook 14 (3): 107-110.
2. Russell, P. 2003. Taking the path of least resistance. Pesticide Outlook 14 (2): 57-61.

Return to Virginia IPM Home

E. Bush, last updated 12/19/05

Virginia Cooperative Extension - Virginia Agriculture & Experiment Station