The discovery of isoxazoline oxime ethers as a new class of ectoparasiticides for the control of Haematobia irritans (horn fly) in cattle.

Abstract Haematobia irritans (horn fly) infestation in cattle is responsible for over a billion dollars a year in global economic loss due to decreased milk production and lower feed conversion. There is significant need for new insecticidal agents since current treatments such as organophosphates and pyrethroids suffer from field resistance. Isoxazoline oxime ethers represent a new class of γ-aminobutyric acid (GABA) receptor channel blockers which show good activity (LD 90  = 1.0 μg/mL) against horn flies in an in vitro feed assay and have demonstrated efficacy (>90% reduction at 1.0 mg/kg) as a topical treatment in a field study.