Which practice best slows resistance development?

• A. Use higher doses of the same pesticide
• B. Rotate modes of action
• C. Apply more frequently
• D. Ignore resistance

Answer: (B)

Rotating modes of action slows resistance development by reducing the selection pressure that pests face from any one pesticide. When the same chemical or same mode of action is used repeatedly, individuals that happen to be naturally resistant survive and reproduce, gradually making the pest population resistant. By switching to products that affect pests in different ways, the survival advantage conferred by resistance to one method is not carried over across treatments, so resistance genes spread more slowly and the overall effectiveness of pesticides is preserved longer. This is why resistance management plans emphasize MOA rotation and why alternatives like increasing dose, applying more often, or ignoring resistance only accelerate the problem.