Larvicidal and residual activity of imidazolium salts against Aedes aegypti (Diptera: Culicidae).

BACKGROUND: Aedes aegypti is an important mosquito species that can transmit several arboviruses such as dengue fever, yellow fever, chikungunya and zika. Because these mosquitoes are becoming resistant to most chemical insecticides used around the world, studies with new larvicides should be prioritized. Based on the known biological profile of imidazolium salts (IS), the objective of this study was to evaluate the potential of six IS as larvicides against Ae. aegypti, as tested against Ae. aegypti larvae. Larval mortality was measured after 24 and 48 h, and residual larvicidal activity was also evaluated.

RESULTS: Promising results were obtained with aqueous solutions of two IS: 1-n-octadecyl-3-methylimidazolium chloride (C18 MImCl) and 1-n-hexadecyl-3-methylimidazolium methanesulfonate (C16 MImMeS), showing up to 90% larval mortality after 48 h exposure. C18 MImCl was more effective than C16 mIMeS, causing mortality until day 15 after exposure. An application of C18 MImCl left to dry under ambient conditions for at least 2 months and then dissolved in water showed a more pronounced residual effect (36 days with 95% mortality and 80% mortality up to 78 days).

CONCLUSION: This is the first study to show the potential of IS in the control of Ae. aegypti. Further studies are needed to understand the mode of action of these compounds in the biological development of this mosquito species. © 2017 Society of Chemical Industry.