During application, the rate of product applied was higher than the recommended rate, yet control was poor. Which item on the list explains this?

• A. The pest developed resistance to the pesticide
• B. The LD50 of the pesticide is too low
• C. The rate of product applied was too high
• D. The restricted-entry interval was not followed

Answer: (C)

Applying more than the labeled rate doesn’t guarantee better control. In many pesticides, the kill-effect levels off after a certain point, and applying at a rate higher than recommended can even reduce effectiveness. This can happen because pests may avoid surfaces treated with an excessive residue, or the extra product doesn’t translate into more pests being exposed to the active ingredient. So, when control is poor despite the rate being higher than recommended, the most plausible explanation is that the rate used was too high. The other possibilities describe different scenarios: resistance would cause poor control even at proper rates, a very low LD50 would imply high toxicity (usually improving control), and not following a restricted-entry interval concerns human safety, not pest kill.