Surface Application of Different Insecticides Against Two Coleopteran Pests of Stored Products

The present study highlights the critical role of surface type, insect species, and exposure duration in determining the efficacy of surface-applied insecticides in stored-product pest management. Four insecticides were sprayed and evaluated on different surfaces (concrete, metallic, plastic, and ceramic) against two beetles: the red flour beetle and the tobacco beetle. Alpha-cypermethrin and spinosad exhibited rapid and high efficacy, particularly on non-porous surfaces such as metal and ceramic, whereas pirimiphos-methyl was less effective initially and required extended exposure to achieve complete mortality, especially against Tribolium castaneum. In contrast, Lasioderma serricorne showed greater susceptibility across all insecticides and surfaces. Spinosad maintained high efficacy across all surface types, suggesting broader applicability under variable conditions. The reduced performance of insecticides on concrete surfaces underscores the influence of substrate porosity on insecticide bioavailability. Additionally, the observed delayed mortality effect in all treatments indicates that even brief exposure can result in lethal outcomes, emphasizing the long-term potential of these applications. These findings underscore the need for surface-specific application strategies and support the integration of surface treatments into comprehensive pest management programs. Further research is warranted under simulated field conditions to assess residual efficacy over time and in the presence of food, thereby enhancing the relevance of laboratory findings to real-world storage environments.