The companion animal insecticide fluralaner outperforms industry-leading agricultural insecticides in resistant and susceptible strains of filth flies

Authors: BURGESS, EDWIN - Northern Illinois University; Geden, Christopher; Lohmeyer, Kimberly; KING, BETHIA - Northern Illinois University; MACHTINGER, ERIKA - Pennsylvania State University; GAILLARD, ELIZABETH - Northern Illinois University; SCOTT, JEFFREY - Cornell University

Submitted to: Scientific Reports
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 6/10/2020
Publication Date: 7/7/2020
Citation: Burgess, E.R., Geden, C.J., Lohmeyer, K.H., King, B., Machtinger, E.T., Gaillard, E.R., Scott, J.G. 2020. The companion animal insecticide fluralaner outperforms industry-leading agricultural insecticides in resistant and susceptible strains of filth flies. Scientific Reports. 10(1):1-8. https://doi.org/10.1038/s41598-020-68121-z.
DOI: https://doi.org/10.1038/s41598-020-68121-z

Interpretive Summary: Filth flies are responsible for billions of dollars per year in losses to the animal production industry. Heavy reliance on chemical control has resulted in widespread resistance to the limited number of insecticides available for filth fly control. In this paper a team of researchers at Northern Illinois University, USDA-ARS-CMAVE (Gainesville, Florida), USDA-ARS Kerrville, TX, Penn State University and Cornell evaluated the effectiveness of the novel insecticide Floralaner against house flies and horn flies. When it was fed to flies in a sugar bait, fluralaner was 23-fold more toxic than imidacloprid to a susceptible house fly strain and over 117-fold more toxic in an imidacloprid-resistant house fly strain. It also out-performed permethrin when it was applied directly to the flies. At present, fluralaner is only registered for use on dogs and cats for flea control. Our results indicate that this material would be very useful against insecticide-resistant flies.

Technical Abstract: Filth flies are responsible for billions of dollars per year in losses to the animal production industry. Heavy reliance on chemical control has resulted in widespread resistance to the limited number of insecticides available for filth fly control. Here we found that fluralaner outperforms two of the most widely used insecticides against several strains of susceptible and resistant flies. When orally administered, fluralaner was about 23-fold more toxic than imidacloprid to a susceptible house fly strain and over 117-fold more toxic in an imidacloprid-resistant house fly strain. A small amount of cross-resistance to fluralaner was seen in both oral and topical applications to pyrethroid-resistant house flies, but in topical applications, fluralaner still vastly outperformed permethrin in all strains. In topical tests on horn flies, fluralaner outperformed permethrin by over 2-fold at 24 h and increased another 2-fold between 24 and 48 h. Fluralaner did not outperform permethrin topically in susceptible stable flies at 24 h.