Pesticides, such as fungicides, insecticides, herbicides, etc., may be classified by their biochemical activity (i.e. mode of action [MOA]). When pesticide resistance develops to a pesticide with a particular MOA, all other pesticides that possess the same MOA will also have pesticide resistance. Brand names, active ingredients, even the chemical class of pesticides may differ, while their MOA may be the same. The bottom line is the MOA—if resistance develops within the pest population to the MOA, all pesticides within that MOA group are resistant.

See the industry-based pesticide resistance action committee websites for MOA information and classification:

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

Cronshaw, K. 2004.  Fungicide resistance: some practical aspects. Outlooks on Pest Management 15 (6): 272-275.

E. Bush, last updated 12/19/05

Virginia Cooperative Extension - Virginia Agriculture & Experiment Station