Evaluation of Bifenthrin and Deltamethrin Barrier Sprays for Mosquito Control in Eastern North Carolina

Mosquitoes can be a nuisance and also transmit pathogens causing numerous diseases worldwide. Homeowners and others may hire private companies to alleviate mosquito-related issues. Here, two pyrethroids (Suspend[registered] Polyzone[registered] [deltamethrin] and Bifen Insecticide/Termiticide [bifenthrin]) used in mosquito control were evaluated on blocks of properties in two neighborhoods (Magnolia Ridge: 1-6 lot blocks, 2,100 -- 7,500 m2/block and Cedar Ridge: 1-3 lot blocks, 1,300 -- 4,200 m2/block) in eastern North Carolina for 23 weeks from May 18 -- October 19, 2015. Properties were treated by Mosquito Authority operators using backpack mist blowers every 21 days. At 17 fixed sampling locations (13 treatment and four control lots), Centers for Disease Control and Prevention CO2-baited traps were deployed overnight once/week for the duration of the experiment (377 trap nights). Oviposition traps (ovitraps) were deployed weekly at the same 17 locations and ovistrips remained in the field for seven days as a measure of Aedes albopictus abundance. Mosquitoes were identified to species, quantified, and tabulated by location and week. Differences were observed in mosquito abundance between neighborhoods, treatments, and weeks and differences varied between species. Adult and egg abundance were generally significantly (P [less than] 0.05) higher in traps placed on control properties (no insecticide) compared to traps placed on treatment properties. In both neighborhoods, the abundance of Psorophora columbiae and Ae. vexans was significantly higher in control versus treatment traps. Bifenthrin and deltamethrin showed differences in efficacy (e.g. Ae. vexans, An. punctipennis, and Ps. ferox abundance was greater in traps placed on bifenthrin compared to deltamethrin and control properties), but this varied between neighborhoods and species