Pesticide Science (1999) 55, 386-389

Guy Smagghe, Bert Carton, Wim Wesemael, Isaac Ishaaya and Luc Tirry (1999)
Ecdysone agonists - mechanism of action and application on Spodoptera species
Pesticide Science 55 (3), 386-389
Abstract: Laboratory assays using artificial diet demonstrated that tebufenozide (RH-5992) and the new structural analogue, RH-2485 (proposed common name methoxyfenozide), possess strong ecdysone-like activity against last-instar larvae of the beet armyworm, Spodoptera exigua, and the cotton leafworm, Spodoptera littoralis, leading to precocious lethal moulting. LC₅₀ values showed that the activity of RH-2485 (0.38 mg AI litre^-1) was about twice that of tebufenozide (0.60 mg AI litre^-1) in S. exigua, whereas in S. littoralis respective LC₅₀ values were 1.15 mg AI litre^-1 and 9.51 mg AI litre^-1. The retention-fate curves of ¹⁴C-radiolabelled ecdysone agonist could not explain the differential toxicity values between species and compounds. Ingestion of the oxidase inhibitor piperonyl butoxide (PB) synergized the toxicity of the ecdysone agonist, indicating the importance of oxidative detoxifcation in Spodoptera larvae, and may raise the possible use of PB as synergist for this group of insecticides, or for monitoring resistance due to increased oxidation.
(The abstract is excluded from the Creative Commons licence and has been copied with permission by the publisher.)
Database assignments for author(s): Wim M.L. Wesemael, Guy Smagghe, Luc Tirry, Isaac Ishaaya

Research topic(s) for pests/diseases/weeds:
control - general
molecular biology - genes

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Pest and/or beneficial records:

Beneficial	Pest/Disease/Weed	Crop/Product	Country	Quarant.
	Spodoptera exigua
	Spodoptera littoralis