Why might some pests develop resistance to pesticides?

Pests may develop resistance to pesticides primarily due to the overuse of a single pesticide type. When a particular pesticide is repeatedly used in the same environment, it can exert selective pressure on the pest population. This means that individuals within that population may possess or develop genetic traits that confer resistance to the active ingredient in the pesticide. Over time, these resistant individuals survive and reproduce, leading to a population that is dominated by resistant pests.

This phenomenon is particularly common with systemic or long-lasting pesticides that maintain their effectiveness for extended periods. In contrast, using a variety of pesticides or employing integrated pest management strategies can reduce the chance of developing resistance, as these approaches expose pests to different modes of action and reduce their survival chances.