| Summary: | The residual efficacy of novaluron on concrete, metal and wood was evaluated against last-instar larvae of <i>Oryzaephilus surinamensis</i> (L.), <i>Tribolium</i><i>castaneum</i> (Herbst), and <i>Trogoderma granarium</i> Everts. The larvae and food provided for survival were exposed to surfaces pretreated at rates of 0.053, to 0.209 mg/m<sup>2</sup> and bioassays were conducted from 0- to 16-weeks post-treatment. Percentage emergence of adults was recorded after 30 days (d). On all surfaces at week 0, no <i>O. surinamensis</i> or <i>T.</i><i>castaneum</i> adults emerged, and ≤3.3% emergence of <i>T. granarium</i> was found at 0.209 mg/m<sup>2</sup>. Novaluron significantly reduced the percentage emergence of adults of the three species compared to a distilled water control for the first 12 weeks on all the tested surfaces as the residual efficacy declined at a low rate during initial weeks and then at a high rate in the final weeks of the 16-week study. Reductions to emergence were most persistent on metal surfaces, with mean percentages of adult emergence of ≤18.3 in week 12, followed by concrete (≤32.5) and wood (≤45.0) for all species at novaluron application rates of 0.209 mg/m<sup>2</sup>. For >4-weeks protection, higher application rates would be needed to avoid buildup of pest populations and reductions in profitability. Such results can be helpful for the management of <i>O. surinamensis</i>, <i>T.</i><i>castaneum</i>, and <i>T. granarium</i> as the costs of commonly used insecticides against postharvest insect pests and the resistance of these insects to the pesticides gradually increase in mills, warehouses, and food storage facilities.
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