Pesticides are designated high or low risk based on health and environmental risks. High risk pesticides have a greater potential to negatively impact non-target organisms, whereas low risk pesticides have a low potential to negatively impact non-target organisms. The trend in pesticide development is toward lower risk pesticides due in part to the 1996 Food Quality Protection Act, which significantly raised the safety/risk bar for pesticides currently registered and those facing registration, in addition to constraints associated with current trends in research and development.

Biorational pesticides, sometimes termed bio-pesticides, pose a very reduced or no risk to the environment. These products are used in small quantities and degrade rapidly, leaving little residue. Biorationals, unlike other pesticides, are safely handled. Examples of biorational pesticide products include:

• Growth regulators
• Oils
• Soaps
• Biological control agents
  • Biological control agents are living organisms used to control pests. Viruses, nematodes, fungi, bacteria, insects, mites, and other living organisms may be used for biological control. Biological control agents may be predators, which kill pests, parasites, which infest and gain nutrients from pests, weakening or killing the pest; or pathogens, which cause disease to develop in the pest. Biological controls are used to control weed, nematode, insect and plant pathogens. Biological controls are typically specific to certain pests and not useful for controlling a broad range of pests. Therefore, the pest problem must be accurately identified before selection of a specific biological control agent.
  • Decreasing the use of pesticides that negatively impact non-target organisms may allow populations of organisms that are naturally antagonistic to pests to develop. Fostering habitats in fields, gardens, and landscapes and in non-cultivated areas that promote a diversity of organisms (i.e. antagonistic organisms) can increase natural populations of biological control agents. For example, increasing organic matter content in the soil and providing a diversity of flowering plants encourages development of beneficial populations of organisms that may be naturally antagonist to pests.
• Pheromones
• Minerals
• Myco-herbicides

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.
3. United States, EPA. Cairns, C. 2005. EPA Funds grant for project on biorational pesticides in nursery crops: Could biorational pesticides replace traditional formulas? http://www.epa.gov/pesticides/local/region4/news/abc0305.htm
4. Ware, G.W. and Whitacre, D.M. 2004. The Pesticide Book, 6th Ed. MeisterPro Information Resources, Willoughby, OH. Pp. 293-315.
5. Whitford, F., ed. 2002. The Complete Book of Pesticide Management : Science, Regulation, Stewardship, and Communication, vol. XXIV. 787 pp. J. Wiley, New York. 

E. Bush, last updated 12/19/05

Virginia Cooperative Extension - Virginia Agriculture & Experiment Station