The 24-h survival of susceptible, resistant, and F1 hybrid horn flies, Haematobia irritans (L.), was measured on caged steers with zero, one, two, or four pyrethroid-impregnated ear tags in place for up to 16 wk. With the susceptible strain, survival on one- and two-tagged steers was equal to 3% and 0.2%, respectively, of the survival on untreated steers. With the resistant strain, survival on one- and two-tagged steers was equal to 97% and 107%, respectively, of the survival on untreated steers. With the hybrid (heterozygote resistant) flies, survival on one-, two-, and four-tagged steers was equal to 61%, 23%, and 11%,respectively, of the survival on untreated steers. Heterozygote survival did not change during the 16 wk of treatment for two-tagged steers. These findings suggest that the survival of heterozygous-resistant flies from the onset of tag use has been responsible for the rapid evolution of pyrethroid resistance among U.S. horn fly populations.
Document Type: Research Article
Publication date: December 1, 1987
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Journal of Economic Entomology is published bimonthly in February, April, June, August, October, and December. The journal publishes articles on the economic significance of insects and is divided into the following sections: apiculture & social insects; arthropods in relation to plant disease; forum; insecticide resistance and resistance management; ecotoxicology; biological and microbial control; ecology and behavior; sampling and biostatistics; household and structural insects; medical entomology; molecular entomology; veterinary entomology; forest entomology; horticultural entomology; field and forage crops, and small grains; stored-product; commodity treatment and quarantine entomology; and plant resistance. In addition to research papers, Journal of Economic Entomology publishes Letters to the Editor, interpretive articles in a Forum section, Short Communications, Rapid Communications, and Book Reviews.