Skip to Main Content
U.S. Forest Service
Caring for the land and serving people

United States Department of Agriculture

Home > Search > Publication Information

  1. Share via EmailShare on FacebookShare on LinkedInShare on Twitter
    Dislike this pubLike this pub
    Author(s): Michael J. Firko; Janes Leslie Hayes
    Date: 1990
    Source: J. Econ. Entomol., Vol. 83(4): 1222-1228
    Publication Series: Miscellaneous Publication
    PDF: View PDF  (3.33 MB)


    We examined relationships between larval weight and degree of resistance to cypermethrin in tobacco budworm, Heliothis virescens (F.). Laboratory-reared larvae (9.0-175.4 mg) were treated with either 0.1 or 1.0 mg cypermethrin in acetone. Degree of debilitation of each larva was assessed at intervals from 0.5 h to 5 d after treatment cumulative scores incorporating degree of debilitation and survival time were used as a measure of tolerance (i.e. a continuous measure of resistance). at larval weights ( 100 mg, relationships between tolerance and weight were linear for both doses. At the rate of 0.1 mg per larva, tolerance reached an asymptote near 100 mg. Proportion of tolerance variation explained by weight decreased with size range, but we obtained significant relationships over weight ranges frequently used in Heliothis studies. Weight and dose interacted; slopes of tolerance weight regressions were steeper at the lower dose (large larvae were disproportionately more tolerant than small larvae). These data indicate that the expression of tolerance and tolerance changes within populations are mediated by even small-scale weight variation, that relationships between tolerance and weight depend on dose, and that it my be possible to refine resistance predictions by account for weight variation in treated populations.

    Publication Notes

    • You may send email to to request a hard copy of this publication.
    • (Please specify exactly which publication you are requesting and your mailing address.)
    • We recommend that you also print this page and attach it to the printout of the article, to retain the full citation information.
    • This article was written and prepared by U.S. Government employees on official time, and is therefore in the public domain.


    Firko, Michael J.; Hayes, Janes Leslie. 1990. Quantification of larval resistance to Cypermethrin in tobacco budworm (Lepidoptera: Noctuidae) and the effects of larval weight. J. Econ. Entomol., Vol. 83(4): 1222-1228


    Insects, Heliothis virescens, insecticide resistance, continuous measure

    Related Search

    XML: View XML
Show More
Show Fewer
Jump to Top of Page