Inheritance and Effective Dominance of Pyrethroid Resistance in the Horn Fly (Diptera: Muscidae)

Abstract

In laboratory assays, pyrethroid resistance in the horn fly, Haemotobia irritans (L.), appears to be inherited as a single, autosomal, incompletely recessive gene, consistent with a knock-down (nerve insensitivity) type of resistance. Bioassays of heterozygous and susceptible flies on tagged steers suggest that resistance is also incompletely recessive under field conditions. Data indicate that effective residues of pyrethroids dissipate from treated cattle within 7 days after removal of tags.