Economic decision rules for IPM

Abstract

The year 2009 marks the 50th anniversary of the elaboration of the economic injury level (EIL) and the economic threshold (ET) concepts by Stern et al . (1959). The EIL and ET are widely recognized as the most important concepts in IPM. Because IPM is posited on the premise that certain levels of pests and pest injury are tolerable, the EIL and ET represent a crucial underpinning for any theory of IPM. Given the centrality of economic decision rule concepts to IPM, it follows that every IPM program should be based on these concepts. But this clearly is not the case. Why? In this chapter, we will discuss the historical development of economic decision levels, current approaches, and limitations of the EIL and ET. Finally, we will argue that EILs should be incorporated much more into IPM programs and that EILs are central to the continued development of environmental and economic sustainability concepts so important to IPM. Economic decision levels The concept of tolerating pest injury was not introduced by Stern et al . (1959); it was discussed at least as early as 1934 (Pierce, 1934) but does not seem to have been developed further until 1959 (Kogan, 1998). In response to failures in pest control in California because of insecticide resistance by pests and insecticide mortality of natural enemies, Stern et al . (1959) first proposed the fundamental concepts of the EIL, the ET, economic damage and pest status.