What is the economic injury level?

• A. The maximum pest population tolerated before initiating control measures
• B. It is essentially the 'break-even point' when the cost of control equals the amount of damage
• C. The economic threshold at which ignoring pest damage has no consequences
• D. The point at which pesticide resistance develops

Answer: (B)

The economic injury level is the pest population density at which the economic losses from pest damage equal the cost of control. It represents the break-even point for deciding whether to treat, meaning if pest levels are below this point, control costs exceed the value of the damage prevented, and treatment isn’t justified; if at or above this point, applying control becomes economically worthwhile. This concept is distinct from the economic threshold, which is set lower to trigger action before reaching the EIL to prevent losses. The other ideas described—tolerating a pest population, having no consequences from damage, or pesticide resistance developing—do not define the EIL.