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Comparative ecdysteroid action of ring‐substituted dibenzoylhydrazines in Spodoptera exigua
Author(s) -
Smagghe Guy,
Nakagawa Yoshiaki,
Carton Bert,
Mourad Ahmed Kamal,
Fujita Toshio,
Tirry Luc
Publication year - 1999
Publication title -
archives of insect biochemistry and physiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.576
H-Index - 66
eISSN - 1520-6327
pISSN - 0739-4462
DOI - 10.1002/(sici)1520-6327(1999)41:1<42::aid-arch7>3.0.co;2-h
Subject(s) - beet armyworm , exigua , spodoptera , biology , ecdysteroid , ecdysone , lepidoptera genitalia , 20 hydroxyecdysone , chilo suppressalis , pyralidae , indoxacarb , biochemistry , larva , botany , pesticide , gene , agronomy , recombinant dna
Ring‐substituted dibenzoylhydrazines are well known as nonsteroidal ecdysone agonists that cause precocious larval molt leading to death. Among them, tebufenozide (RH‐5992) is used in practice as insecticide to control lepidopteran pests selectively. Recently, a new dibenzoylhydrazine, methoxyfenozide (RH‐2485), with a higher activity for Lepidoptera, has been discovered. To obtain insight into the molecular mechanisms involved in the insecticidal selectivity of the dibenzoylhydrazine family, we measured the in vivo toxicity of these dibenzoylhydrazines against larval stages of the beet armyworm, Spodoptera exigua, and their action on in vitro cultured imaginal discs. We found that both nonsteroidal ecdysone agonists induced premature and lethal molting, and caused the same effect as 20‐hydroxyecdysone in vitro. Furthermore, we measured the larvicidal activity against S. exigua of a series of dibenzoylhydrazines, in which ring‐substituents were varied in a range of halogen, lower alkyl, OCH 3 , SCH 3 , Ph, CN, NO 2 , and CF 3 . The substituent effects on the larvicidal activity against S. exigua were very similar to that for another lepidopteran insect species Chilo suppressalis, suggesting that the molecular mechanism of action of these compounds is similar within both lepidopteran species. Arch. Insect Biochem. Physiol. 41:42–53, 1999. © 1999 Wiley‐Liss, Inc.