This week during ICM Conference, I talked about a resistance management plan for soybean aphid. My presentation abstract can be downloaded now (ICM Proceedings, pg. 97). In order to prolong the efficacy of foliar insecticides, farmers need to implement more scouting, spray based on the economic threshold, check fields post spray, and rotate insecticide groups. When it comes to options for insecticide groups for soybean aphid in Iowa, there are relatively few to choose from…mostly they are organophosphates [group 1B] and pyrethroids [group 3A].
You may not know about the Insecticide Resistance Action Committee (IRAC); it is the definitive global authority on the target site of insecticides. IRAC has defined 29 groups so far. The IRAC website does a nice job of listing the insecticide groups and how they work to kill insects. See the IRAC Modes of Action list. Insecticide labels should include the insecticide group, so it should be easier to know what is being applied. They also have a good video explaining more about insecticide resistance, found on the IRAC website.
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- Professor
- Extension Entomologist Specialist
- ANR Crops Team Leader