Reversal of resistance to pyriproxyfen in the Q biotype of Bemisia tabaci (Hemiptera: Aleyrodidae)

Margaret Wilson, Pnina Moshitzky, Einat Laor, Murad Ghanim, A. Rami Horowitz, Shai Morin*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

27 Scopus citations


Pyriproxyfen, a juvenile hormone (JH) mimic, is a biorational insecticide that disrupts insect development. It is one of the principal insecticides being used to control Bemisia tabaci (Gennadius) on cotton, and has many environmentally positive attributes that make it compatible with integrated pest management (IPM) programs. In Israel, a high level of resistance to pyriproxyfen has been observed in several isolated regions. Here, tests were conducted to establish whether temporal refuges from exposure to pyriproxyfen could be useful for restoring the effectiveness of the compound. Resistance was found to decrease by a factor of 8 when exposure to pyriproxyfen was ceased for 13 generations. Reversal of resistance was accompanied with increased biotic fitness of the revertant colony. By incorporating experimental estimates of nymph survival, sex ratio, fecundity, egg hatching rate and developmental time, the seasonal cost per generation for resistant insects was estimated to be 25%. A genetic simulation model, optimized by empirical data from bioassays, predicted fitness cost per generation of 19% for resistant homozygous (RR) females and hemizygous (R) males, and produced rates of reversal similar to the experimental results. The model also predicted that, even after 5 years (∼ 55 generations) without pyriproxyfen treatments, the frequency of the resistance allele (R) will still remain high (0.02). It is therefore concluded, on the basis of experimental and modeling results, that the effectiveness of temporal refuges for reversing development of resistance to pyriproxyfen in B. tabaci may be limited.

Original languageAmerican English
Pages (from-to)761-768
Number of pages8
JournalPest Management Science
Issue number8
StatePublished - Aug 2007


  • Bemisia tabaci
  • Fitness cost
  • Insect growth regulator (IGR)
  • Insecticide resistance
  • Modeling
  • Pyriproxyfen


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