Which would increase the likelihood of pesticide resistance?

The likelihood of pesticide resistance is significantly increased by the continual use of the same pesticides or those from the same chemical class. This practice exposes pests to the same active ingredient repeatedly, allowing any individuals with a natural resistance to survive and reproduce. Over time, these resistant individuals can become more prevalent in the population, diminishing the effectiveness of that pesticide and potentially leading to a situation where it is no longer effective at all.

In contrast, applying a pesticide with little or no residual effect would not contribute to resistance because the pesticide would not be present long enough to allow for selection pressure on the pest population. Limiting the number of pesticide applications reduces overall exposure, which can help mitigate resistance. Also, having an insect that only has one generation per year limits the opportunities for the pests to reproduce and develop resistance in response to pesticide application.