Resistance Management

Preventing and Managing Insecticide Resistance

Insecticide Resistance Management (IRM) strategies are becoming more important in today's fruit and vegetable production systems. IRM strategies help prevent insects from developing resistance to today's chemistries. Preventing and managing resistance to insecticides is an important stewardship practice that ensures insect control products will remain effective long-term. Delegate^® WG and Radiant^® SC insecticides, which contain the unique active ingredient spinetoram, are powerful new IRM tools that are helping fruit and vegetable growers.

What is Insecticide Resistance?

Certain pests naturally possess resistance traits that help them survive against insecticide applications. If insects are repeatedly exposed to an insecticide, these pests are able to tolerate the insecticide. After several applications of the insecticide, the resistant insects are the only ones left, and can pass the resistance to their offspring.

The Insecticide Resistance Action Committee (IRAC) estimates that insecticide resistance in the United States costs the agriculture industry $40 million a year in additional treatment costs. Even so, insecticides remain one of the most effective tools for controlling pests.

Practicing Integrated Pest Management

Using multiple management strategies is the best way to effectively prevent resistance to insecticides. Practicing the IPM approach prevents insects from developing resistance to any one product and helps keep valuable insecticide management tools viable. Dow AgroSciences recommends the following resistance management guidelines for Delegate^® WG and Radiant^® SC insecticides.

Create a season-long insect control plan to avoid any unnecessary insecticide applications.
Consider planting early maturing varieties of plants that are more resistant to late-season insect attack.
Consult an IPM adviser about the use of beneficial insects, synthetic and biological insecticides, crop rotation and other cultural practices that can be incorporated into crop production.
Select insecticides based on a product's impact on beneficial insects. Products like Delegate and Radiant maintain populations of most beneficial insects – including ladybeetles, lacewings, predatory mites and parasitic wasps – that can assist in keeping damaging insect populations in check.
Rotate different insecticide modes of action, or classes, throughout the season. Using the same insecticide mode of action year after year increases the risk of insects developing resistance to that particular mode of action. Ultimately this will destroy the effectiveness of that pest management tool. Delegate and Radiant contain a new mode of action for insect control.
Use insecticides at labeled rates and spray intervals only. Using reduced rates of an insecticide can result in incomplete control that can lead to resistance development.
Apply insecticides properly. Check and calibrate all application equipment on a regular basis to ensure good spray coverage. Proper pruning of tree crops can allow for better penetration into the canopy. Always use the application volumes and techniques found on the product label.
When tank-mixing insecticide products for better broad-spectrum control, mix products with different modes of action.
Time applications for best results. Apply insecticides during the most vulnerable life stage of the target insect to get the best control.
Monitor pest populations during the growing season. Only use insecticides if the local economic threshold for a target pest has been reached.
See the Insecticide Resistance Action Committee's Mode of Action Classification for more information on classes of insecticides. If in doubt of the mode of action, or class, of a particular product, or products being used in a rotation, consult the product labels or contact your local Extension agent.