2018 Crop Protection Guide for Tree Fruits in Washington

Pesticide Resistance Management

Thursday, June 21, 2018

Insecticide Resistance Management

Recent registration of several new insecticides with several unique modes of action has made the possibility of proactive resistance management possible.  With proper stewardship of the new insecticides, their longevity should be increased and the risk of resistance evolution decreased.  Practicing resistance management and proper IPM practices will reduce the likelihood of resistance, and could prevent the initial development of resistance problems.  

  • Use alternatives to insecticides, such as biological control and mating disruption
  • Make spray decisions based on pest thresholds, rather than prophylactic applications
  • Target the most susceptible life stage of the pest; optimize timing for pests using models
  • Make applications in proper conditions to ensure good coverage
  • Rotate insecticide modes of action


Rotation is one of the most important resistance management strategies in tree fruit IPM.  When rotating modes of action, use any one mode of action against only one generation of one insect species per year.  This means that growers should not reuse a mode of action at a later time in the season simply because the target insect species has changed.  Instead, because many of the insecticides have activity against more than one pest, the insecticide choice for any timing should consider effects against all pests in the orchard.  Multiple modes of action can be used against a pest in the same generation, however, all of those modes of action should not be used again in subsequent generations. 

Tree Fruit Research & Extension Center, 1100 N Western Ave, Washington State University, Wenatchee WA 98801, 509-663-8181, Contact Us