Another issue related to pesticide use that poses significant challenges is the development of pesticide resistance. Pesticide resistance occurs when pest populations gain the ability to withstand pesticides (e.g. insecticides, fungicides and herbicides). In other words, pesticides that were formerly effective against pests lose their effectiveness and the pesticide is no longer of use. Since pesticides typically require long-term research and development, in addition, to a lengthy and costly registration process with the EPA, an effective pesticide is a valuable tool that warrants stewardship. Once a pesticide is lost due to pesticide resistance, there is no guarantee that an effective replacement will be available. In fact, due to increasingly stringent registration requirements, the probability is that a comparable replacement will not be available or may be a very long time in getting to the marketplace.

Pesticide resistance is gaining more attention and becoming a more pressing problem as pesticides are generally becoming more targeted to specific pests. The benefit of these targeted pesticides is that they are typically much safer (lower risk pesticides) both ecologically and in terms of human health. Furthermore, the trend in pesticide development is toward these 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. The downside to these targeted, lower risk pesticides is that they are typically prone to the development of resistance in pest populations. Therefore the issue of pesticide resistance will likely become more important as higher risk pesticides (i.e. more deleterious effects to environment and health) are phased-out and low risk pesticides become the norm. :

Russell, P. 2003. Taking the path of least resistance. Pesticide Outlook 14 (2): 57-61.  

• Fungicide Resistance Action Committee
• Herbicide Resistance Action Committee
• Insecticide Resistance Action Committee

E. Bush, last updated 12/19/05

Virginia Cooperative Extension - Virginia Agriculture & Experiment Station