Mobility and dispersal of two cosmopolitan stored-product insects are adversely affected by long-lasting insecticide netting in a life stage-dependent manner

Authors: WILKINS, RACHEL - KANSAS STATE UNIVERSITY; ZHU, KUN YAN - KANSAS STATE UNIVERSITY; Campbell, James - Jim; Morrison, William - Rob

Submitted to: Journal of Economic Entomology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 4/13/2020
Publication Date: 5/15/2020
Citation: Wilkins, R.V., Zhu, K., Campbell, J.F., Morrison III, W.R. 2020. Mobility and dispersal of two cosmopolitan stored-product insects are adversely affected by long-lasting insecticide netting in a life stage-dependent manner. Journal of Economic Entomology. 113(4):1768-1779. https://doi.org/10.1093/jee/toaa094.
DOI: https://doi.org/10.1093/jee/toaa094

Interpretive Summary: The red flour beetle and warehouse beetle are serious and widespread pests of finished products after milling and processing. Long-lasting, insecticide-incorporated netting, has historically been used as bed nets to hinder the spread of malaria by targeting the vector. We are currently evaluating the effectiveness of this netting at preventing the dispersal of stored product insect pests as part of an integrated pest management program for grain and food facilities. We determined insecticide netting can be effective against both immature larval stages and adult stages of the red flour beetle and warehouse beetle. Adult beetles experienced significant and long-lasting, multiple-fold impairment of movement and dispersal ability compared to adults not exposed to the netting. This is important, because adults are the dispersing life stage for both of these species; we demonstrated that they will not be even able to move 10 inches after contact, which is a trivial distance considering the footprint of most massive food facilities. Larval movement and dispersal were also significantly impaired, though larvae appeared slightly less affected by netting. Overall, the differences between life stages are minimal, and insecticide netting appears effective against not just multiple species, but also multiple life stages.

Technical Abstract: Tribolium castaneum (Herbst) (Coleoptera: Tenebrionidae) and Trogoderma variabile Ballion (Coleoptera: Dermestidae) are two stored product insects that cause extensive damage to a variety of post-harvest commodities. Long-lasting insecticide netting (LLIN), commonly used to control vector-borne diseases in tropical regions, has only been recently studied in an agricultural setting. While prior research showed that LLIN was successful against stored product beetles, little is known about differential susceptibility among stored product insect life stages. The aim of this study was to evaluate LLIN efficacy against immature T. castaneum and T. variabile compared to adults. Movement and dispersal ability were evaluated after exposure to LLIN or an untreated, control netting. For the movement assay, video-tracking software recorded the post-exposure effects of LLIN on distance-traveled and velocity of the insects in 2 h trials. For the dispersal assay, insects were exposed to the netting then released into one end of a PVC pipe and allowed 48 h to disperse to a novel food patch located at the opposite end of the pipe. Our study found that movement and dispersal ability of T. variabile and T. castaneum are significantly reduced, often by multiple-fold, after LLIN exposure, with the larval stage of each species more tolerant to the insecticide netting than adults. These results indicate that LLIN is a promising tool for use in intercepting immigrating insects of different life stages in food facilities to protect stored products.