Susceptibility of oriental fruit moth (Lepidoptera: Tortricidae) to two pyrethroids and a proposed diagnostic dose of esfenvalerate for field detection of resistance

Moneen M. Jones, Jacqueline L. Robertson, Richard A. Weinzierl

Research output: Contribution to journalArticlepeer-review

Abstract

Laboratory colonies of oriental fruit moth, Grapholita molesta (Busck) (Lepidoptera: Tortricidae), were reared on 'Gala' apples (Malus pumila Mill.) and lima bean (Phaseolus lunatus L.) diet. Neonates were placed on wheat germ diet containing a range of concentrations of esfenvalerate or lambda-cyhalothrin; mortality was assessed after 96 h. For a long-term laboratory colony, LC 50 values of esfenvalerate and lambda-cyhalothrin were 0.35 and 0.12 ppm, respectively, for progeny of insects reared on apples. For a colony established from Calhoun Co., IL, in 2007, LC 50 values of esfenvalerate and lambda-cyhalothrin were 0.37 and 0.10 ppm, respectively, for progeny of insects reared on apples. LC 50 values of these insecticides did not differ significantly for either colony when progeny of insects reared on lima bean diet were tested. We observed no consistent evidence of pyrethroid resistance in the Calhoun colony after laboratory culture for 21-23 generations. We described the dose-response relationship for esfenvalerate applied topically in 1 μl of acetone to male moths from the long-term laboratory colony and estimated the LD 99 to be 0.022 μg per moth. Application of 0.022 μg of esfenvalerate per moth to ≈ 600 male moths from two putatively susceptible populations resulted in mean survivorship approximately equal to the expected level of 1.0%. Application of the same dose to 374 field-captured moths from two Calhoun Co. orchards with histories of pyrethroid use resulted in mean survivorship of 9.4 and 82%. We propose that 0.022 μg of esfenvalerate in 1 μl of acetone can be used as a diagnostic dose for monitoring pyrethroid resistance in oriental fruit moth in the field.

Original languageEnglish (US)
Pages (from-to)1031-1037
Number of pages7
JournalJournal of economic entomology
Volume104
Issue number3
DOIs
StatePublished - Jun 1 2011

Keywords

  • Grapholita molesta
  • bioassays
  • resistance monitoring

ASJC Scopus subject areas

  • Ecology
  • Insect Science

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