Widespread resistance of insect pests to insecticides has been widely reported in China and there is consequently an urgent need to adjust pest management strategies appropriately. This requires detailed information on the extent and causes of resistance. The aim of the present study was to investigate levels of resistance to 5 insecticides among 12 strains of Culex tritaeniorhynchus, a major vector of Japanese encephalitis in China. Resistance to deltamethrin, beta-cypermethrin, permethrin, dichlorvos, and propoxur were measured using larval bioassays. The allelic frequency of knockdown resistance (kdr) and acetylcholinesterase (AChE) mutations were determined in all strains. Larval bioassay results indicated that the field strains collected from different sites were resistant to deltamethrin, beta-cypermethrin, permethrin, dichlorvos, and propoxur, with resistance ratio values ranging from 1.70- to 71.98-fold, 7.83- to 43.07-fold, 3.54- to 40.03-fold, 291.85- to 530.89-fold, and 51.32- to 108.83-fold, respectively. A polymerase chain reaction amplification of specific alleles method for individual was developed to detect genotypes of the AChE gene mutation F455W in Cx. tritaeniorhynchus. The frequency of the AChE gene mutation F455W was 100.00% in all strains, making this mutation of no value as a marker of resistance to organophosphorous and carbamate pesticides in Cx. tritaeniorhynchus in China. The kdr allele was present in all strains at frequencies of 10.00–29.55%. Regression analysis indicated a significant correlation between kdr allele frequencies and levels of resistance to deltamethrin, beta-cypermethrin, and permethrin. These results highlight the need to monitor and map insecticide resistance in Cx. tritaeniorhynchus and to adjust pesticide use to minimize the development of resistance in these mosquitoes.
You have requested a machine translation of selected content from our databases. This functionality is provided solely for your convenience and is in no way intended to replace human translation. Neither BioOne nor the owners and publishers of the content make, and they explicitly disclaim, any express or implied representations or warranties of any kind, including, without limitation, representations and warranties as to the functionality of the translation feature or the accuracy or completeness of the translations.
Translations are not retained in our system. Your use of this feature and the translations is subject to all use restrictions contained in the Terms and Conditions of Use of the BioOne website.