The effects of shelving type, packaging, and release height on success of Trichogramma deion parasitizing Plodia interpunctella eggs was studied under laboratory conditions. In trials on gondola-type or open shelving units, with or without packaging, foraging success was tracked by comparing parasitism and total mortality rates of sentinel egg disks among shelves after a single point-release of T. deion. Results showed that T. deion parasitized more egg disks and killed more total eggs on open shelves than on gondola shelving. The presence of packaging did not significantly affect parasitoid foraging on open shelves, but packaging did reduce egg parasitism on gondola shelving. Furthermore, egg parasitism and mortality patterns among shelves were not as evenly distributed on gondola-type shelving as they were on open shelving. On empty gondola shelves, changing the release point of T. deion from the middle to the lowest shelf shifted the distribution of parasitism towards the floor. Gondola shelving may have provided a physical barrier that interfered with the vertical movement of T. deion among shelves; thus, reducing foraging efficiency. However, a central release point provided the most even coverage of shelves on both shelving types.