Technical Abstract: Populations of Plodia interpunctella (Hübner), the Indianmeal moth, were monitored inside a 105,000 m3 food warehouse in the central United States for a 3-year period, using pheromone-baited traps for males. A total of 52 traps were placed in the warehouse, which was roughly divided into four main areas. Ten traps were placed on the grounds outside the warehouse. Total inside moth catch was nearly 50,000 for the three-year study, suggesting a large population was present within the warehouse. Moth captures both inside and outside the warehouse generally peaked during the summer months, and few adult males were caught during the cooler months of the year. Within a year, trap locations where greater numbers of moths were captured varied over time within the warehouse. Trap locations in an area where food was not stored consistently captured adults, but this area was connected to the main part of the warehouse that contained the stored food. Inside temperatures were above 15°C for most of the year, while outside temperatures were consistently above 15°C from mid-May to mid-October. Economic analysis of conducting a monitoring program were calculated using estimates for fixed costs of traps and variable costs for labor that were provided by private industry, calculating labor costs for in-house monitoring versus outside contractor costs, and comparing those estimates with research costs of conducting the program (three different scenarios). A threshold trap catch level of two males per day was used to describe methodologies for reducing total trap numbers and associated economic costs, with minimal loss of data resolution.