Impact of Residual Insecticide Applied to Upper Story Vegetation on Resting Adult Mosquitoes (Diptera: Culicidae)

R. T. Trout, G. C. Brown

Abstract


Increased threat of mosquito-vectored diseases necessitates the development for new management tactics and programs. We tested a pyrethroid barrier treatment by using a power sprayer to target upper tree canopies against orniphilic and other resting mosquitoes. Mosquito populations were monitored weekly with CO2-baited Centers for Disease Control (CDC) miniature light traps (without a light) (1) d level and within the vegetation. Traps were operated weekly for 10 weeks; 2 weeks pre- and 8 weeks post-treatment. Culex spp. were collected predominantly in tree canopy CO2-baited traps (81%) compared with CO2-baited traps at ground level (11%) and gravid traps (7%). Over 96% of the mosquitoes collected were Culex spp. Pretreatment canopy catches averaged 489.7 and 618.6 adults per trap-night prior to insecticide treatment in the control and treatment plots, respectively. Tree canopy treatments significantly reduced populations of Aedes spp. and Culex spp. At 4 weeks post-treatment, mosquito numbers collected in CO2-baited traps were reduced by 86% at ground level and 76% in tree canopies. No reduction in mosquito numbers was noted in gravid traps. These data demonstrated that pyrethroid barrier sprays applied to upper canopy vegetation might be effective in reducing adult mosquito populations.

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