Earth fill increases efficacy and longevity of ¿-cyhalothrin residual insecticide treatment of HESCO® blast wall geotextile

Authors: Gibson, Seth; CILEK, SETH - Navy Entomology Center Of Excellence, Cmave Detachment; LINDROTH, ERICA - Navy Entomology Center Of Excellence, Cmave Detachment; Aldridge, Robert; Golden, Frances; WEESTON, JOSHUA - Navy Entomology Center Of Excellence, Cmave Detachment; FAJARDO, JASON - Navy Entomology Center Of Excellence, Cmave Detachment; RICHARDSON, ALEC - Navy Entomology Center Of Excellence, Cmave Detachment; BLERSCH, JESSIKA - Department Of Defense; Linthicum, Kenneth - Ken

Submitted to: Journal of the American Mosquito Control Association
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 2/12/2020
Publication Date: 6/30/2020
Citation: Britch, S.C., Cilek, S.C., Lindroth, E.J., Aldridge, R.L., Golden, F.V., Weeston, J.R., Fajardo, J.D., Richardson, A.G., Blersch, J.S., Linthicum, K. 2020. Earth fill increases efficacy and longevity of ¿-cyhalothrin residual insecticide treatment of HESCO® blast wall geotextile. Journal of the American Mosquito Control Association. 67:36-50.

Interpretive Summary: United States military personnel in the field are persistently exposed to biting insects which impact the success of military missions because of severe nuisance or, worse, transmission of viruses, parasites, bacteria, and other dangerous pathogens. One way to reduce the amount of contact between humans and biting insects is by treating perimeters around field camps with a contact insecticide which may kill or debilitate insects before they can reach personnel. These perimeters can be naturally occurring vegetation, but can also be perimeters of materials commonly used around military camps such as camouflage netting or portable blast protection walls. The latter, also known as HESCO barriers, are made up of a welded steel cage lined with a heavy fabric that may be filled with rocks, sand, and/or soil from the surrounding terrain. In previous studies we have shown that HESCO material treated with insecticide is highly effective at reducing populations of biting insects that would otherwise penetrate through a perimeter towards people. However, previous studies were not able to assess the pesticide treatment on HESCO filled with soil, raising the concern that the presence of soil might affect the performance of the pesticide. In the present study we found that soil filled HESCO in fact perform at least as well if not better than non-soil filled HESCO when both kinds are treated with pesticide, and importantly the soil filled HESCO pesticide treatment lasts much longer than the treatment on a non-soil filled HESCO. These findings not only support immediate implementation of this technique in US military field scenarios but also provide evidence that HESCO technology used in natural disaster flood control -- where the HESCO and pesticide treatment would be in contact with moist soil -- could be leveraged to protect civilian personnel from emerging floodwater mosquitoes.

Technical Abstract: The prevention of mosquito- and sand fly-borne disease to protect the health and readiness of deployed United States forces in the field continues to be a high priority for the US Department of Defense. Previous studies have demonstrated that the risk of human contact with disease-vector mosquitoes and sand flies can be reduced by applying residual insecticide to perimeters of military materials such as camouflage netting or HESCO blast protection wall geotextile that are already in place around troops in the field. In this study we investigate whether residual pesticide efficacy will persist in the presence of earth fill that is required for operational use of HESCOs at a field site in a warm temperate environment north Florida. Results from both bioassay mosquito mortality measured in the laboratory and field collections of natural mosquito populations indicate superior efficacy and greater longevity of pesticide treated geotextile exposed to soil fill. These findings not only support immediate implementation of this technique in US military field scenarios but also provide evidence that HESCO technology used in natural disaster flood control could be leveraged to protect civilian personnel from emerging floodwater mosquitoes.