First, because an understanding of the agricultural ecosystem is essential to preventing pest problems. Second, because IPM relies upon close monitoring of pest populations in order to determine when a population has reached an economically damaging threshold. Scouting is the primary method of monitoring pest populations to determine if an economic threshold is reached. It refers to the periodic and systematic sampling of pests in the field in order to estimate population levels. Computer models based on weather conditions and other factors are used also to predict the onset and severity of a pest outbreak.
Monitoring is employed in tracking populations of beneficials as well as pests.
The use of conventional pesticides in an IPM program may differ from that of a traditional chemical program. In other words, the farmer determines how serious a problem is and what management options are available before action is taken. Using IPM requires the grower to understand how the crop grows, how different pest populations develop, what the control options are in each specific pest management case, and what the return on investment of these control options is along with the potential impact on the environment and health. To attain the benefits of an IPM program, more information must be gathered, integrated into a body of knowledge and implemented. The extra work can be offset by the resulting benefits from reduced costs of chemicals inputs, cleaner environment, and decreased resistance problems.