What might indicate pesticide resistance in pest populations?

The indication of pesticide resistance in pest populations is typically characterized by a situation where higher than normal pest populations are observed alongside reduced efficacy of the pesticides being applied. When pests develop resistance, they can survive treatments that would normally kill them, leading to an increase in their numbers.

This phenomenon occurs as those pests that are less susceptible to the pesticide survive and reproduce, resulting in a population that is more resistant over time. As a consequence, attempts to control these pests with the same pesticide may yield diminishing results, hence the connection between rising pest numbers and decreased effectiveness of control measures.

In contrast, increased effectiveness of various pesticides suggests the opposite scenario where the products are working well against the pest population, while rapidly declining pest populations typically indicate successful control of the pests, suggesting that resistance is not present. Stable behavior in pest activity would imply that pest populations aren't changing significantly, which would not indicate resistance either. Thus, the right choice points clearly to the signs that suggest resistance has developed.