Effects of nutrition on recovery, mortality, and mobility of adult Tribolium castaneum after exposure to long-lasting insecticide-incorporated netting

Authors: MING, QINGLEI - Kansas State University; Morrison, William - Rob; ZHU, KUN YAN - Kansas State University; Campbell, James - Jim; Scully, Erin

Submitted to: Pest Management Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 7/22/2024
Publication Date: N/A
Citation: N/A

Interpretive Summary: Contact insecticides are commonly used to treat and prevent infestations of stored product insects in large food facilities and in flour mills. Although they are commonly effective and long-lasting in many environments, there are many factors that can reduce their efficacy. Interestingly, the presence of food is associated with recovery after exposure to these insecticides in a variety of stored product insects, but it is unclear whether this is due to metabolic processes that are stimulated by feeding or because the food acts as a physical barrier against contact with the insecticide. In this study, we tested the efficacy of two different long-lasting insecticide nettings (LLINs) containing two different insecticides in the presence of food against red flour beetle (Tribolium castaneum), a global pest of stored products. We also determined whether the nutritional quality of the food influences recovery by mixing wheat flour with varying percentages of cellulose (0% cellulose to 100% cellulose), which contains very few nutrients. Although the presence of food did not influence recovery immediately after exposure, recovery and reduced mortality was observed 1-7 days after exposure when the beetles had access to either flour or cellulose. Recovery was also substantially higher and mortality lower in diets containing higher percentages of flour. Altogether, these results suggest that there are multiple mechanisms to recovery: 1) the fact that non-nutritive cellulose increased recovery suggests that the food provides a physical barrier against contact with the insecticide and 2) the fact that recovery was even higher in the presence of flour suggests that metabolic processes stimulated by feeding are likely involved in detoxifying the insecticide. Overall, this data reinforces the idea that cleaning up small spillage piles of flour or dust will improve the effectiveness of insecticides against stored product insects in the field.

Technical Abstract: Long-lasting insecticide-incorporated netting (LLIN) has been used to deliver contact insecticides as an integrated pest management tool for stored product insect pests in food facilities. Although the presence of food is known to improve insect recovery after exposure, it is not clear whether food nutritional quality has played a role in it. Here, we evaluated the effectiveness of two commercially available LLINs Carifend (active ingredient: a-cypermethrin) and D-Terrence (deltamethrin) against adult Tribolium castaneum and investigated the effects of foods with varying nutritional quality (e.g., those that contained different ratios of flour to non-nutritive cellulose) on adult recovery, mortality, and mobility. After exposure for 2 to 168 h, the immediate mortality of T. castaneum adults ranged from 0.5% to 91.0% with Carifend and 0% to 75.3% with D-Terrence. Adult recovery and delayed mortality were significantly affected by nutritional quality, LLIN type, exposure time, and recovery time. For both LLINs, adult recovery increased over time, with a trend for higher recovery and lower mortality with increasing nutritional quality and decreasing exposure time. In addition, adult mobility decreased by multiple-fold after Carifend or D-Terrence exposure for 30, 60 or 90 min compared to 10 min. This study shows nutrition significantly modulates the efficacy of LLIN against T. castaneum, and thus strengthens the rationale for implementing stringent sanitation protocols for food facility managers.