Economic threshold

Definition

In integrated pest management, the pest population density at which the cost of applying a control measure equals the economic value of the damage prevented by that measure; above this density, intervention becomes economically justified.

Etymology

Example

In soybean agroecosystems, the economic threshold for corn earworm (Helicoverpa zea) is typically set at one larva per 25 plants during early reproductive stages; below this density, scouting continues, but above it, insecticide application is recommended.

Synonyms

• action threshold
• treatment threshold

Related Terms

• Economic injury level
• Integrated Pest Management
• pest density
• scouting
• injury equivalency

Usage Notes

Often confused with economic injury level (EIL), which is the pest density causing losses equal to control costs; the economic threshold is set below the EIL to allow time for control implementation before losses reach the EIL. Thresholds are crop-specific, growth-stage-specific, and market-price-dependent. Specialists distinguish between fixed thresholds (static density values) and dynamic thresholds (adjusted for commodity prices, control costs, or plant compensation capacity).