The involvement of microsomal oxidases in pyrethroid resistance in Helicoverpa armigera from Asia

摘要: Abstract Five contemporary strains of the bollworm Helicoverpa armigera Hubner from China, Pakistan and India, all with high resistance to pyrethroids, were compared a standard susceptible strain that originated Cote D’Ivoire in 1970s (‘SCD’). Two Chinese (‘YGF’ ‘YGFP’) derived by laboratory selection third, field collected (‘YG’). The ‘YG’ exhibited 7-, 14- 21-fold fenvalerate, cypermethrin deltamethrin, respectively. After fenvalerate for 14 generations (‘YGF’), this increased 1690-, 540- 73-fold. Selection mixture piperonyl butoxide (PBO) (‘YGFP’) resulted ratios 2510, 2920 286. synergistic pre-treatment PBO 5-, 462- 12-fold YG, YGF YGFP strains, Resistance Pakistani (PAK) 2320-, 4100- 223-fold ratio these pyrethroids was 450-, 950- 11-fold. strong synergism implied an oxidative metabolism could be involved pyrethroid resistant strains. activities cytochrome P450 monooxygenases midguts final instar larvae p -nitroanisole (PNOD), ethoxycoumarin (ECOD), methoxyresorufin (MROD) significantly when strain. This further implies are Asian H. . Comparative vitro studies C-deltamethrin midgut microsomes PAK SCD showed had much greater capacity than metabolic degradation deltamethrin. enhanced occurred presence NADPH which suggested detoxification. In minor increases glutathione S -transferase activity (to substrates CDNB DCNB), esterase substrate α-naphthyl acetate) that, putative mechanisms, oxidases most important. study provides first evidence major mechanism responsible Asia.