Application of insecticides to vegetation as barriers against host-seeking mosquitoes.

The application of insecticides to perimeter vegetation for the purpose of controlling adult mosquitoes in backyards and other recreational areas has generated renewed interest among the general public. Several pyrethroids have been labeled for this use and provided, depending on chemical and formulation, up to approximately 6 wk of acceptable adult mosquito reduction. A review of past work in this area is presented. In addition, results from a recent field study by the author to determine the residual effectiveness of bifenthrin-treated vegetation as a barrier against adult mosquitoes in northwestern Florida is also presented. Bifenthrin (TalstarOne) suppressed mosquito populations in the treatment area below an annoyance action threshold of 25 mosquitoes per night in carbon dioxide-baited light traps for 5 out of the 8-wk study. Excised leaf bioassays conducted at the same time as trap collections revealed that bifenthrin-treated leaves exhibited > 70% knockdown/mortality against laboratory-reared female Aedes albopictus and Culex quinquefasciatus for 4 of those weeks.