Which of the following is a reason for pesticide failure related to pest adaptation?

• A. Pesticide resistence
• B. Pesticide is highly effective
• C. Pests do not exist in treated area
• D. Pesticide affects only non-target species

Answer: (A)

Pesticide failure due to pest adaptation happens when the pest population develops resistance to the chemical after repeated exposure. In any pest population there’s genetic variation, and some individuals may have traits that let them detoxify the chemical, alter the pesticide’s target, or avoid exposure. Those survivors reproduce, increasing the frequency of resistance traits in the population, so the pesticide becomes less effective over time. Common resistance mechanisms include enhanced metabolic breakdown of the pesticide, changes at the target site that reduce binding, reduced uptake or increased efflux of the chemical, and behavioral changes that avoid treated areas. This kind of failure arises from evolution in the pest, not from the pesticide being inherently ineffective. The other options describe situations that don’t involve adaptation: a pesticide that’s highly effective shows success, pests not existing in the treated area means nothing to control, and affecting only non-target species relates to selectivity rather than pest adaptation.