D3253: Recovery of Tribolium castenum (Herbst) after exposure to long-lasting insecticidal netting in the presence of food

Long-lasting insecticidal netting (LLIN) have been widely used for control of insect-vectored diseases such as malaria, but recently, researchers have adapted the use of LLIN to agricultural environments. The red flour beetle, Tribolium castaneum (Herbst), is a serious pest of stored products that differ in their nutritional quality. The purpose of this experiment was to determine whether the nutritional quality of foods impacted insect recovery after exposure to two types of LLIN that had different active ingredients, one containing 0.4% deltamethrin and the other containing 0.34% alpha-cypermethrin. After exposure to ten different exposure times (ranging from 2 to 168 hrs), insect recovery was measured in the presence of no food and diets containing different ratios of wheat flour to non-nutritive microcrystalline cellulose (0:100, 5:95, 25:75, or 100:0) for up to 7 days post-exposure. Both LLIN were successful at causing knockdown even after brief exposures and in the absence of food recovery rates were < 20%. However, recovery rates were at or above 80% for both LLIN when beetles were in the presence of 100% flour for exposure times of less than 24 hrs and after 1 day of recovery. Recovery was directly correlated with the percentage of wheat flour in the mix. Substantial recovery over 50% was also observed for exposure times of up to 120 hrs when food was provided. This study shows the importance of sanitation when utilizing LLIN for integrated pest management in post-harvest environments because food has a direct impact on the efficacy of LLIN.