COMPARATIVE ASSESSMENT OF THREE AUTOMATED MISTING SYSTEM NOZZLES AGAINST AEDES AEGYPTI

Abstract

Automated misting systems have become popular with the public for ‘do-it-yourself’ mosquito control around residences. However, these systems have largely been evaluated as whole systems without attention to key components such as the nozzle design. The nozzle designs directly atomize bulk liquid into an aerosol, a critical function of any spray delivery system. In this study we investigated the atomization performance of single nozzles from three manufacturers – Gman, Freezanz, and MistAway, and their efficacy at three pressures against adult Aedes aegypti mosquitoes in a laboratory wind tunnel. There was significant difference among flow rates from the three nozzles at all three pressures, with the highest flow rate from the Gman nozzle. The difference in mean volume median diameter (DV0.5) among the three nozzles was significant and generally smaller droplets were produced by the Gman nozzle. For all three nozzles droplets became smaller and the flow rate became higher with increasing pressure. However, the mean mosquito mortality from sprays of synergized permethrin as well as mortality at any pressures were not significantly different across the three nozzle types. There was no correlation between pressure and 24-h mortality for all nozzles. Despite the apparent equivocal performance against mosquitoes across all three nozzle types, we discuss operational implications of significant differences in flow rate across the tested nozzles that should be considered when using these systems.