Toxicity of ecdysone agonists correlates with the induction of CHR3 mRNA in the spruce budworm

M. Sundaram, S. R. Palli, I. Ishaaya, P. J. Krell, A. Retnakaran

Research output: Contribution to journalArticlepeer-review

21 Scopus citations


Four ecdysone agonists, RH-5849, RH-5992, RH-0345, and RH-2485, were tested for toxicity against fifth-instar larvae of Choristoneura fumiferana. RH-2485 was the most toxic (LD50 = 1.05 ng/larva) followed by RH-5992 (LD50 = 8.8 ng/larva), RH-0345 (LD50 = 41.0 ng/larva), and RH-5849 (LD50 = 236.9 ng/larva). The relative potencies of these compounds to induce the transcription factor Choristoneura hormone receptor 3 (CHR3) was studied. Detectable levels of CHR3 mRNA were induced by RH-2485 at a concentration as low as 1.5 ng/larva, but similar inductions required concentrations as high as 7.5 ng of RH-5992/larva, 37.5 of RH-0345/larva, and 187.5 of RH-5849/larva. The order of potency of these four ecdysone agonists for inducing CHR3 mRNA is the same as their larval toxicity.

Original languageEnglish
Pages (from-to)201-208
Number of pages8
JournalPesticide Biochemistry and Physiology
Issue number3
StatePublished - Dec 1998

Bibliographical note

Funding Information:
We thank Rohm and Haas company scientists for supplying compounds, Dr. Sardar S. Sohi for critical comments on the manuscript, Ms. K. Jamieson for editorial help. This research was supported by a Canadian Forest Service/Natural Sciences and Engineering Research Council Research Partnership Program Award CRD No. 0192158, with Rohm and Haas Company.


  • Hormone receptor 3
  • Pest control
  • RH-0345
  • RH-2485
  • RH-5849
  • RH-5992
  • Spruce budworm
  • Transcription factor

ASJC Scopus subject areas

  • Agronomy and Crop Science
  • Health, Toxicology and Mutagenesis


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