Mobility of adult Tribolium castaneum (Coleoptera: Tenebrionidae) and Rhyzopertha dominica (Coleoptera: Bostrichidae) after exposure to long-lasting insecticide netting

Authors: Morrison, William - Rob; WILKINS, RACHEL - Kansas State University; Gerken, Alison; Scheff, Deanna; ZHU, KUN-YAN - Kansas State University; Arthur, Franklin; Campbell, James - Jim

Submitted to: Journal of Economic Entomology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 4/30/2018
Publication Date: 9/26/2018
Citation: Morrison III, W.R., Wilkins, R.V., Gerken, A.R., Scheff, D.S., Zhu, K., Arthur, F.H., Campbell, J.F. 2018. Mobility of adult Tribolium castaneum (Coleoptera: Tenebrionidae) and Rhyzopertha dominica (Coleoptera: Bostrichidae) after exposure to long-lasting insecticide netting. Journal of Economic Entomology. 111(5):2443-2453. https://doi.org/10.1093/jee/toy173.
DOI: https://doi.org/10.1093/jee/toy173

Interpretive Summary: The key to stored product insect integrated pest management (IPM) programs for food facilities that handle grain and grain-based products is prevention because of the costs associated with treating insects once they enter a facility and the risks associated with infestation of the finished product. Given the mobility of the insects and limitations of currently available barriers, new methods to prevent infestation are needed. Long-lasting insecticide netting has been used to reduce the spread of malaria since the 1990s. More recently, it has been used to manage pests in pre-harvest agriculture in tree fruit and post-harvest agriculture with stored product pests. This netting could be used as barrier at food facilities to reduce insect movement into structures. Because stored product insects are too small for the netting to be an effective physical barrier, we assessed whether brief contact with the netting resulted in reductions in mobility and dispersal capacity of red flour beetle and lesser grain borer, two cosmopolitan and economically destructive stored product pests. Brief 1-min exposures resulted in the same 3-4-fold decrease in mobility as longer 10-min exposures to insecticide netting compared to controls without insecticide. Similarly, dispersal capacity of red flour beetle was reduced by 20-fold, while dispersal was completely absent in the lesser grain borer; controls in both cases dispersed without issues. Overall, our results show that short exposure to the netting, while not providing immediate mortality, did reduce the movement of the insects to the point where their ability to cause infestations was greatly reduced. These results contribute significantly to the prospect of diversifying integrated pest management programs for stored product insects.

Technical Abstract: Stored products represent an enormous economic output, but insects regularly immigrate into stored products from the surrounding landscape throughout the post-harvest supply chain. Long-lasting insecticide netting (LLIN), which usually contains an impregnated pyrethroid, has been used as part of a strategy to reduce the spread of malaria in tropical regions since the 1990s, and has only recently been considered for its application in pre- and post-harvest agricultural contexts. The goal of this study was to determine how short term exposure to LLINs in the laboratory impacts the locomotory behavior and mortality for adult Tribolium castaneum (Herbst), red flour beetle, and Rhyzopertha dominica (Fauvel), lesser grain borer, at different periods of time after exposure. Exposure to LLINs resulted in multiple-fold reductions in the distance moved and an elevated angular velocity in both species that quickly took effect and persisted even after 168 h compared with adults exposed to control netting. Rhyzopertha dominica was somewhat more susceptible than T. castaneum to LLINs. Finally, the dispersal capacity of both species, measured as ability to move to a remote resource patch, was significantly impaired or absent after exposure to LLINs compared to adults exposed to control netting. Our results demonstrate that LLINs are a promising new technology for reducing infestation by stored product insects since even short exposures limit movement and ultimately lead to knockdown and death.