Pest Management Science (2004) 60, 465-473

Mushtaq Ahmad and Robert M. Hollingworth (2004)
Synergism of insecticides provides evidence of metabolic mechanisms of resistance in the obliquebanded leafroller Choristoneura rosaceana (Lepidoptera: Tortricidae)
Pest Management Science 60 (5), 465-473
Abstract: The interactions between six insecticides (indoxacarb, cypermethrin, chlorpyrifos, azinphos-methyl, tebufenozide and chlorfenapyr) and three potential synergists, (piperonyl butoxide (PBO), S,S,S-tributyl phosphorotrithioate (DEF) and diethyl maleate (DEM)) were studied by dietary exposure in a multi-resistant and a susceptible strain of the obliquebanded leafroller, Choristoneura rosaceana (Harris). The synergists did not produce appreciable synergism with most of the insecticides in the susceptible strain. Except for tebufenozide, PBO synergized all the insecticides to varying degrees in the resistant strain. A very high level of synergism by PBO was found with indoxacarb, which reduced the resistance level from 705- to 20-fold when PBO was administered alone and to around 10-fold when used in combination with DEF. DEF also synergized indoxacarb, cypermethrin, chlorpyrifos, azinphos-methyl and tebufenozide in the resistant strain. DEM produced synergism of indoxacarb, chlorpyrifos, azinphos-methyl and chlorfenapyr in the resistant strain. DEM was highly synergistic to cypermethrin, and to some extent to tebufenozide in both the susceptible and resistant strains equally, implying that detoxification by glutathione S-transferases was not a mechanism of resistance for these insecticides. The high level of synergism seen with DEM in the case of cypermethrin may be due to an increase in oxidative stress resulting from the removal of the antioxidant, glutathione. These studies indicate that enhanced detoxification, often mediated by cytochrome P-450 monooxygenases, but with probable esterase and glutathione S-transferase contributions in some cases, is the major mechanism imparting resistance to different insecticides in C. rosaceana.
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Link to article at publishers website
Database assignments for author(s): Mushtaq Ahmad

Research topic(s) for pests/diseases/weeds:
pesticide resistance of pest
control - general

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Pest and/or beneficial records:

Beneficial	Pest/Disease/Weed	Crop/Product	Country	Quarant.
	Choristoneura rosaceana