In IPM, Economic Threshold is defined as the pest density at which management action should be taken to prevent an increasing population from reaching the Economic Injury Level.

• A. The pest density at which the cost of pest damage equals the cost of control
• B. The pest density at which management action should be taken to prevent an increasing population from reaching the Economic Injury Level
• C. The maximum pest density tolerated without any action
• D. The average pest density observed in the field

Answer: (B)

Economic Threshold in IPM is the pest density at which you should act to prevent the population from reaching the Economic Injury Level. This point is set below the level where damage costs would equal control costs if you did nothing, giving you time to apply management and keep losses from escalating. The other descriptions describe different ideas: one defines the Economic Injury Level itself—the pest density where damage costs equal the cost of control if no action is taken; another describes a maximum that you would tolerate without action; and the last is just an average density, which doesn’t guide when to intervene. In practice, the threshold is deliberately lower than the injury level to account for growth, time needed to implement controls, and effectiveness of the treatment.