Which term describes the pest population density that causes losses equal to the cost of control measures?

• A. Economic injury level
• B. Economic threshold
• C. Action threshold
• D. Tolerance

Answer: (A)

The main idea is balancing costs: the pest density at which the economic losses from damage equal the cost of control is the point where treatment becomes cost-effective. That density is called the economic injury level. Below this level, the damage isn’t worth the cost of control, and above it, applying control helps justify the expense because losses exceed the control costs. The economic threshold, in contrast, is the pest level at which you should start control to prevent reaching the economic injury level, usually set lower to allow time for application. Tolerance refers to how much damage the crop can tolerate before yields drop, not the point where control costs balance damage.