A comparative analysis of resistance testing methods in Aedes albopictus (Diptera: Culicidae) from St. Johns County, Florida

Aedes albopictus Skuse (Diptera: Culicidae) was tested for resistance to permethrin, bifenthrin, and malathion using Centers for Disease Control and Prevention (CDC) bottle bioassays and topical toxicology assays on adults and larval bioassays. Eggs were collected from 3 locations across St. Johns County, Florida, raised to the F3 generation and compared with an insecticide susceptible laboratory strain. Results from CDC bottle bioassays with permethrin indicate no significant differences between the 3 wild-type strains and the laboratory strain but suggest the possibility of resistance in 1 strain. Bottle bioassay results for malathion were inconclusive. Topical toxicological results for adults and bioassays for larvae showed a significant difference in permethrin resistance between the control strain and 1 of the wild-type strains. Results from this project indicate that insecticide susceptibility testing should be a regular part of mosquito surveillance programs. Upon detection of resistance, detailed dose response bioassays should be performed to quantify the resistance and mechanisms in local vector populations.