Assessing permethrin susceptibility of field-collected biting midges in Florida and evidence for resistance evolution using laboratory selections

Authors: Pitzer Jr, Jimmy; COOPER, VILMA - Florida Medical Entomology Laboratory; Taylor, Caitlin; Phillips, Evan; BURKETT-CADENA, NATHAN - Florida Medical Entomology Laboratory; Shults, Phillip

Submitted to: Medical and Veterinary Entomology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 3/25/2026
Publication Date: 4/9/2026
Citation: Pitzer Jr, J.B., Cooper, V., Shults, P.T., Taylor, C.E., Phillips, E.S., Burkett-Cadena, N. 2026. Assessing permethrin susceptibility of field-collected biting midges (Diptera: Ceratopogonidae) in Florida and evidence for resistance evolution using laboratory selections. Medical and Veterinary Entomology. https://doi.org/10.1111/mve.70070.
DOI: https://doi.org/10.1111/mve.70070

Interpretive Summary: Biting midges (Culicoides spp.) are small blood-feeding insects that pose a significant threat to livestock and wildlife due to their role in transmitting serious viral diseases such as bluetongue virus, epizootic hemorrhagic disease virus, and vesicular stomatitis virus. Control of these pests has relied heavily on insecticide treatments which are applied directly to animals, around premises, or to barriers like mesh or fabric. However, little is known about how effective specific insecticides are against local midge species or how likely these insects are to develop resistance. To address this gap, we tested the efficacy of permethrin, a commonly used insecticide, on both lab-reared and wild midges in Florida. Results showed that lab-reared midges were significantly more tolerant than their wild counterparts, and wild midges were more susceptible than mosquitoes to permethrin sprayed from the ground. However, many midge species occupy forest canopies, which likely limits exposure to ground-level applications. Importantly, the study found that biting midges can develop significant resistance to permethrin in just two generations, raising concerns about long-term reliance on this control strategy. These findings mark the first documented evidence of potential insecticide resistance in Culicoides spp., underscoring the need for targeted, species-specific management strategies to better control midge populations and reduce disease transmission risks.

Technical Abstract: Culicoides biting midges (Diptera: Ceratopogonidae) remain economically important dipteran pests of livestock and other animals worldwide. In addition to their blood-feeding nuisance behaviors, they serve as biological vectors of several animal pathogens, including bluetongue virus, epizootic hemorrhagic disease virus, and vesicular stomatitis virus. Efforts to limit biting midge access to target hosts such as cattle and sheep have relied predominantly on insecticide use. However, research regarding biting midge insecticide efficacy largely has been focused on animal and barrier treatments using formulated commercial products, with little effort to identify local endemic species level susceptibility to specific active ingredients. Therefore, a study was conducted to determine the susceptibility of biting midges under laboratory and field conditions, as well as determine the potential for insecticide resistance development by these pests. Under laboratory conditions, the susceptibility of a laboratory-reared biting midge colony (Culicoides sonorensis Wirth and Jones (Diptera: Ceratopogonidae)) was significantly less than wild Culicoides spp. Similarly, wild Culicoides spp. also were significantly more susceptible than wild mosquitoes when exposed to an ultra-low volume permethrin application under field conditions. Additionally, a long-established C. sonorensis colony subjected to permethrin selection under laboratory conditions suggested that insecticide resistance development in this pest could occur in field populations if pressured. This is the first account of the potential for insecticide resistance development in Culicoides. The implications of Culicoides spp. insecticide resistance and the lack thereof in assessed field populations are discussed.