Horn Fly Susceptibility to Diazinon, Fenthion, and Permethrin at Selected Elevations in Wyoming1

P. E. Kaufman2, J. E. Lloyd, R. Kumar, and T. J. Lysyk3

Entomology Section
University of Wyoming
P.O. Box 3354
University Station
Laramie, Wyoming 82071

J. Agric. Urban Entomol. 16(2):129-139 April 1999

ABSTRACT

    Horn fly, Haematobia irritans (L.) (Diptera: Muscidae), populations from southeastern Wyoming were assayed for resistance against permethrin, diazinon, and fenthion. All of the populations examined were significantly more resistant to permethrin than a susceptible strain. Eight of 25 populations examined were significantly more resistant to diazinon than a susceptible strain. Five of 15 populations examined were significantly more resistant to fenthion than a susceptible strain. No relationship was detected between elevation and resistance levels.

    KEY WORDS
    Haematobia irritans, Diptera, Muscidae, horn fly, resistance, elevation, bioassay

    1Accepted for publication 30 April 1999.
    2Department of Entomology, Cornell University, Ithaca, New York 14853.
    3Agriculture Canada Research Station, PO Box 3000, Main, Lethbridge, Alberta, Canada T1J 4B1