following fumigation was several times greater in Facility B than in Facility A. As populations of T. castaneum tend to be spatially limited to the confines of the processing facility, population capture rates following fumigation are more likely to be attributed to survivors persisting on habitat patches within the mill that shield them from gas and provide sustenance (Campbell and Arbogast, 2004), with some additional immigration possibly coming from infested product being brought into the facility. Buckley et al.(2009) also attributed rapid re-infestation of European mills following fumigation with methyl bromide and sulfuryl fluoride with poor sanitation practices. Therefore, Facility B's higher firstmonth population levels would lead one to believe that there was a higher treatment survival of insects than Facility A, possibly driven by differences in their sanitation levels.