To reduce the possibility of building up a pest's resistance to a pesticide you can

• A. Make frequent spot treatments with the same pesticide
• B. Apply higher weekly doses
• C. Use only natural enemies
• D. Apply pesticides only when pests reach economic threshold

Answer: (A)

To slow pest resistance, you limit how often and how much a single pesticide is used and mix in other control methods. The most effective approach is to apply pesticides only when pests reach an economic threshold, so you intervene only when crop damage justifies treatment. This reduces the number of exposure events the pest population experiences, which in turn slows the development of resistant individuals. In addition, rotating pesticides with different modes of action and integrating non-chemical controls (like cultural practices, scouting, and biological controls) further lowers the selection pressure that drives resistance.

Frequent spot treatments with the same pesticide continually expose most of the pest population to that chemical, promoting survivors with resistance and speeding up resistance buildup. Using higher weekly doses increases exposure and selection pressure without necessarily improving control and can disrupt beneficial organisms. Relying solely on natural enemies helps but isn’t enough on its own to prevent resistance if chemical use continues at unnecessary times. Applying pesticides only at economic thresholds, along with rotating modes of action, provides the most robust resistance management.