Thresholds are a critical part of any integrated pest management (IPM) program. The thresholds presented here are economic thresholds, in which the density of a pest has reached a point at which a management intervention (in this case a pesticide application) is economically justified. An economic threshold should not be confused with the economic injury level. An economic injury level is the lowest population density of a pest that will cause economic damage (Stern et al. 1959). Treatment when economic injury level is reached may result in the highest yields, but may not necessarily be the most cost-effective. Treatment at the economic threshold is the most cost-effective management approach, and may or may not result in the highest yields.
Thresholds are only part of integrated pest management. Please consult the individual pest pages for various management strategies and tactics.
Stern, V.M., R.F. Smith, R. van den Bosch, and K.S. Hagen. 1959. The integrated control concept. Hilgardia. 29: 81-99.