Sampling Insect Populations for the Purpose of IPM Decision Making

Decision making is a key aspect of current integrated pest management (IPM) programs and will continue to play an important role as IPM programs mature (71, 106). In an IPM context, decision making relies on protocols for deciding on the need for some management action based on an assessment of the state of a pest population (and ideally its natural enemies). These protocols, which we refer to as control decision rules, consist of at least two components and may include a third: (a) a procedure for assessing the density of the pest population, (b) an economic threshold (63)';�and (c) a phenological forecast (e.g. 49), which is often necessary to determine the appropriate time to assess popUlation densities. Assessment of pest density usually requires obtaining actual counts of the pests, and therefore, sampling is important. Because sampling is time consuming and expensive, one must know how to gather enough information about pest abundance to be able to make correct decisions without incurring excessive costs. Decision making in IPM is important for two reasons. First, decision­ making protocols can be used to reduce pesticide use. Ideally, IPM relies on benign tactics such as biological control, plant resistance, and cultural prac­ tices to maintain fluctuating pest populations below economic injury levels.