Efficacy of various pyrethroid structures against a highly metabolically resistant isogenic strain of Helicoverpa armigera (Lepidoptera: Noctuidae) from China.
BACKGROUND
Resistance to pyrethroids and other types of insecticides in Helicoverpa armigera (Hübner) has been documented in many countries. The isolation of specific resistance mechanisms in isogenic strains is an optimal approach to investigate cross-resistance pattern, and to validate resistance breaking pyrethroids. In this study an isogenic metabolic resistance CMR strain was successfully isolated from a field pyrethroid-resistant population of H. armigera. With this strain, cross-resistance among 19 pyrethroid insecticides with varying chemical structures was analysed.


RESULTS
Resistance to pyrethroids in the CMR strain was likely to be due to enhanced oxidative metabolism. The most significant cross-resistance in the CMR strain was between pyrethroids such as fenvalerate, tau-fluvalinate and flumethrin characterised by having both phenoxybenzyl and aromatic acid moieties. Substitution of the phenoxybenzyl group with a polyfluorobenzyl group, as in tefluthrin, benfluthrin and transfluthrin, overcame most of this resistance.


CONCLUSIONS
The findings in this study support the assertion that it is possible to find pyrethroids that are active against resistant populations. Such pyrethroids could be considered as possible partners or resistance breaking pyrethroids in a pyrethroid resistance management programme for H. armigera in China and in other Asian countries where the oxidative metabolism resistance is a dominant mechanism.
Tan
Jianguo
J
Department of Entomology, New York State Agricultural Experiment Station, Cornell University, Geneva, NY 14456, USA. jt386@cornell.edu
McCaffery
Alan R
AR
D000818:Animals; D002681:China; D007305:Insecticide Resistance / Q000502:physiology; D007306:Insecticides / Q000737:chemistry; D015394:Molecular Structure; D009036:Moths / Q000235:genetics / Q000378:metabolism*; D010574:Pesticide Synergists; D010882:Piperonyl Butoxide; D011722:Pyrethrins / Q000737:chemistry
D007306:Insecticides; D010574:Pesticide Synergists; D011722:Pyrethrins; D010882:Piperonyl Butoxide