Efficacy of Insecticide with Ethylene Glycol to Aedes aegypti

Wei-Tai Hsia1, Ho-Sheng Wu1, Yi-Chieh Yang1, Cheo Lin1, Ya-Wen Cheng2

2012 Vol.28 NO.16

Correspondence Author： Wei-Tai Hsia

Abstract：

Recently, insecticide with ethylene glycol (EG) sprayed by portable thermal fogger to conduct space spray has become the most popular method in Taiwan to control dengue fever vectors. As an adjuvant, EG could help pest control operator to observe the spread and distribution of insecticide droplets, also to increase the positive impression of residents. However, there was no evidence about its synergic effect and environmental pollution problem. Our study was conducted by Net Cage Test to evaluate the efficacy of insecticide with or without EG to Aedes aegypti. Droplet parameters were measured by Sizing Master. Results showed that EG could not kill mosquitoes, its concentration and droplet parameters are positive related, 50% solution has the best nebulization (Span=0.6, DR=1). Blending with EG would decrease the number of insecticide droplets and widen the droplets diameter, though nebulization remained in an appropriate range, result to enhance the efficacy of insecticide to A. aegypti. The number of droplets decreased may cause by the hydrophilic property of EG which produces larger droplets than insecticide alone. The inhibition of evaporation caused by EG prevents the drift of droplets and prolongs its suspension time; therefore, increase the efficacy of insecticide to A. aegypti. Although EG not only can create visible smog for operator, but also increase insecticides’ efficiency, its toxicity to the operator and resident should be concerned.