Under IPM, when should pesticides be applied?

• A. Only when economic threshold is reached.
• B. Whenever weather permits.
• C. On a calendar schedule.
• D. Immediately upon detecting any pest.

Answer: (A)

In IPM, pesticide use is guided by monitoring pest levels and potential crop damage, not by spraying on a fixed schedule. The decision to apply is based on reaching an economic threshold—the pest population level at which the expected crop loss justifies the cost of control. Applying at this point helps you prevent economic losses while avoiding unnecessary sprays, which slows resistance, protects beneficial organisms, and reduces environmental impact. Weather and other conditions matter for how well a treatment works, but they don’t alone determine whether you should spray. Spraying only when any pest is found would lead to overuse, and calendar-based sprays ignore actual pest pressure. So the best approach is to apply pesticides only when the economic threshold is reached.