Stored-product insects such as Tribolium castaneum (red flour beetle), Sitophilus oryzae (rice weevil), and Rhyzopertha dominica (lesser grain borer) threaten food security by infesting stored grains and processed commodities. This study evaluates the initial and residual efficacy of two contact insecticides, Tempo® SC Ultra (β-cyfluthrin) and Gravista™ (deltamethrin, methoprene, and piperonyl butoxide), applied to wood, metal, and concrete surfaces under controlled temperatures (16, 22, 27, 32, and 37°C) at 65% RH. A total of 675 bioassay arenas (225 per surface type) were prepared using 6 mm plywood, 20-gauge steel, and concrete sections secured in 100 × 20 mm plastic Petri dishes. Each arena was treated with an insecticide using an artist spray brush at label rates. Ten adults of each species were introduced per arena along with a 500 mg diet. Mortality was assessed at 1, 3, and 7 days post-exposure, with residual bioassays conducted every 4 weeks up to 24 weeks post-application. The bioassay conditions were monitored and recorded by using HOBO data loggers. The preliminary results suggest that insecticide efficacy varied significantly across surface types and temperature conditions, generally showing greater lethality as the temperature increased. These findings emphasize the importance of considering various environmental conditions to maximize the efficacy of insecticides in protecting stored grains from insect pest damage and ensuring long-term food security worldwide.