Studies were conducted at two flour mills where male Indian mealmoths, Plodia interpunctella (Hübner), were capturedusing pheromone-baited traps. Objectives were to determine thedistribution of male P. interpunctella at differentlocations in and around the mills throughout the season, and to monitormoth activity before and after one of the mills was fumigated withmethyl bromide to assess efficacy of treatment. Commercially availablesticky traps baited with the P. interpunctella sex pheromonewere placed at various locations outside and within the larger of thetwo mills (mill 1). Moths were captured inside mill 1 after methylbromide fumigations. The highest numbers of P.interpunctella were caught outside the facility and at groundfloor locations near outside openings. Additional traps placed in therooms above the concrete stored-wheat silos at mill 1 during the secondyear captured more moths than did traps within the mill’s productionand warehouse areas. In another study, moths were trapped at variousdistances from a smaller flour mill (mill 2) to determine thedistribution of moths outdoors relative to the mill. There was anegative correlation between moth capture and distance from thefacility, which suggested that moth activity was concentrated at ornear the flour mill. The effectiveness of the methyl bromidefumigations in suppressing moth populations could not be assessed withcertainty because moths captured after fumigation may have immigratedfrom outside through opened loading bay warehouse doors. This studydocuments high levels of P. interpunctella outdoors relativeto those recorded inside a food processing facility. Potential forimmigration of P. interpunctella into flour mills and otherstored product facilities from other sources may be greater thanpreviously recognized. Moth entry into a food processing facility afterfumigation is a problem that should be addressed by pest managers.