Study On Space-time Distribution Of Culex Pipens Pallens/quinquefasciatus Resistance To Common-used Insecticides In China

Culex pipens pallens/quinquefasciatus which distributes abroad in our country, is the major vector of the spot’s filariasis, carrying the Chikungunya virus, Japanese encephalitis virus, and it is one of the main targets of mosquito control.Chemical control is the most commonly used method in integrated pest management for mosquito control. Along with pesticide used wildly, most mosquitoes are exposing the chemicals under long-term resistance selection pressure, and the mosquitoes have developed resistance. This study aimed to establish relative susceptible toxicity baselines based on laboratory researches and historical data, and build database after widely collecting the resistance data of Cx pipiens pallens/quinquefasciatus to commonly used pesticides, then analysis the rule of spatiotemporal distribution of resistance by calculating resistance ratio and provide guidance for resistance management and integrated management of mosquitoes.We established insecticide resistance baselines by comparing the published data or the collected data from National Vector Insecticide Resistance Surveillance System of China (NVIRSS) with that of Cx pipiens susceptible strain which was established through resistance reverse selection to deltamethrin, cypermethrin,permethrin in our lab. Meanwhile we built database through collecting Cx pipiens pallens /quinquefasciatus resistance data from published literature, NVIRSS China, and, the laboratory data. Then we classified the resistance ratio (RR) into 7 grades, and then drawing thematic maps, analysis of temporal and spatial distribution characteristics:1. Comparing to the previous data, BJS strain which was established through reverse selective was highly sensitive to deltamethrin, cypermethrin.2. The LC50 sensitive baseline of Cx pipiens pallens larval to deltamethrin, cypermethrin, permethrin was 0.000034、0.000606、0.00013mg/L respectively.3. The sensitive baseline of adult Cx pipiens pallens metabolism enzymes activities wasGST:10.01 nmol/(min·mg pr),NSE:48.36 nmola-Naphthol acetate (min·mg pr),MFO:2.38 nmol cyt c/mg pr.4. At present most of the Cx pipiens pallens/quinquefasciatus field populations in China had developed resistance to deltamethrin, DDVP at different levels, which was on the rise in recent 30 years..5. The resistance of Cx pipiens/quinquefasciatus field populations to deltamethrin, DDVP presented regional specificity, which sensitiveness of different populations collected from the same region to a pesticide was incompletely consistent, and trends in different regions of resistance to same kind of insecticide was not identical.