Insecticide resistance management in soybean

Insecticide (and miticide) resistance is a heritable decrease in a pest population's susceptibility to a pesticide, meaning the genetics are passed from generation to generation.

As pest populations become less susceptible (i.e., more resistant) to a pesticide, that pesticide’s utility becomes less and less effective. It can reach a point where the pesticide and potentially other related pesticides may become effectively lost as tools for managing that pest.

Since the invasion of soybean aphid in 2000, using foliar insecticides on soybean has greatly increased. In addition, when crop values are high, it stimulates increased adoption of seed treatments and prophylactic foliar treatments.

If not well-managed, this overall increased insecticide use in soybean favors the development of insecticide resistance in pests.

twospotted spider mite
Resistance to the insecticide chlorpyrifos was confirmed in a twospotted spider mite population from southwestern Minnesota in 2012. Photo: John Obermeyer.
soybean aphid
Resistance to pyrethroid insecticides (bifenthrin and lambda cyhalothrin) was documented in a soybean aphid population from southwestern Minnesota in 2015.

Insecticide resistance management strategies

Insecticide resistance management (IRM) is a collection of strategies to prevent or slow the development of insecticide resistance to prolong the utility of pesticides as management tools.

IRM strategies recommended for insect and mite pests in Minnesota soybean include the following.

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Identifying potential resistance

Before assuming resistance, rule out these factors:

  1. Misapplication of insecticide (incorrect insecticide or rate, poor coverage).

  2. Unfavorable weather (wind, rain, temperature). For example, some pyrethroids can be less effective at high temperatures.

  3. Improper timing of application (susceptibility of life stage present).

  4. Recolonization by the pest.

 

If you still suspect insecticide resistance, report insecticide failure or contact Extension.

Insecticides and treatments

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Robert Koch, Extension entomologist; Ian MacRae, Extension entomologist and Bruce Potter, integrated pest management specialist, Southwest Research and Outreach Center

Reviewed in 2018

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