302 - Investigation of Target-site and Metabolic Resistance in Florida Culex quinquefasciatus

Culex quinquefasciatus is a competent vector of many pathogens of public health importance like St. Louis encephalitis virus, Eastern equine encephalitis virus, West Nile virus, and filarial nematodes that cause lymphatic filariasis. The over-reliance on insecticides for mosquito control has resulted in widespread insecticide resistance. The initial focus of our research was to conduct the first statewide survey of Cx. quinquefasciatus insecticide resistance across Florida, providing a baseline characterization of pyrethroid and organophosphate phenotypic insecticide resistance across the state. After characterizing pyrethroid and organophosphate phenotypic insecticide resistance, we investigated the roles that genetic (target-site) and enzymatic resistance mechanisms contribute insecticide resistance in Florida Cx. quinquefasciatus. The susceptibility of Cx. quinquefasciatus populations across 29 counties were examined using the CDC bottle bioassay against two pyrethroid and two organophosphate active ingredients (AIs). We found the resistant Culex L1014F kdr genotype and allele at every county and determined that kdr genetic resistance marginal is role responsible for insecticide resistance. Our results found that enzymatic families alone or in tandem are largely responsible for enzymatic resistance in Florida Cx. quinquefasciatus populations. Data resulting from this investigation potentially will aid Florida mosquito control programs in effectively addressing Cx. quinquefasciatus resistance using synergized control products.