Vector Control, Pest Management, Resistance, Repellents Insecticidal and Behavioral Avoidance Responses of Anopheles minimus and Culex quinquefasciatus (Diptera: Culicidae) to Three Synthetic Repellents Wasana Boonyuan, 1,2 Sunaiyana Sathantriphop, 3 Krajana Tainchum, 2,4 Vithee Muenworn, 5 Atchariya Prabaripai, 6 Michael J. Bangs, 1,7 and Theeraphap Chareonviriyaphap 1,8 1 Department of Entomology, Faculty of Agriculture, Kasetsart University, Bangkok 10900, Thailand (wboonyuan@gmail.com; bangs_michael@yahoo.com; faasthc@ku.ac.th), 2 Center for Advanced Studies for Agriculture and Food, Kasetsart University Institute for Advanced Studies, Kasetsart University, Bangkok 10900, Thailand (CASAF, NRU-KU, Thailand) (roungson09@hotmail. com), 3 Ministry of Public Health, National Institute of Health, Nonthaburi 11000, Thailand (sunaiyana@yahoo.com), 4 Department of Pest Management, Faculty of Natural Resources, Prince of Songkla University, Bangkok 90110, Thailand, 5 Department of Plant Science and Agricultural Resources, Faculty of Agriculture, Khon Kaen University, Khon Kaen 40002, Thailand (vithee_m@live. com), 6 Division of Computer and Statistics, Faculty of Liberal Art and Science, Kasetsart University, Kamphaensean, Nakhon Pathom 73140, Thailand (faasatp@ku.ac.th), 7 Public Health & Malaria Control Department, PT Freeport Indonesia, International SOS, Jl. Kertajasa Kuala Kencana, Papua 99920, Indonesia, and 8 Corresponding author, e-mail: faasthc@ku.ac.th Subject Editor: Lyric Bartholomay Received 14 October 2016; Editorial decision 23 March 2017 Abstract Escape responses, knockdown (KD), and toxicity of laboratory strains of Anopheles minimus Theobald and Culex quinquefasciatus Say to three synthetic mosquito repellents, DEET (N, N-diethyl-3-methylbenzamide), IR3535, or picaridin, at 5% v/v concentrations, were evaluated using repellent-treated papers in standard WHO tube assays and an excito-repellency (ER) test chamber system. The tube assays recorded knockdown effects of each repellent immediately after 30-min exposure and the final morality following a 24-h holding period. DEET showed 100% KD at 30 min and complete toxicity at 24 h against both species. Both actions were either minimal or absent for IR3535 and picaridin, respectively. Culex quinquefasciatus showed significantly greater escape with DEET compared with the other compounds in both contact irritancy (excitation) and noncontact spatial repellency trials. Anopheles minimus showed much more pronounced irritancy and repellency flight escape to IR3535 than picaridin. DEET was the most active irritant and repellent compound against Cx. quinquefasciatus. When adjusting contact test responses based on paired noncontact repellency assays, DEET and IR3535 showed much stronger spatial repellent properties than irritancy with An. minimus. Picaridin performed poorly as an irritant or repellent against both species. We conclude that DEET, followed by IR3535, act as strong spatial repellents at 5% concentration. DEET also performs as a strong toxicant. Our findings show that different mosquitoes can respond contrastingly to repellents, thus the importance to test a wider range of species and populations to assess the full range of chemical action. Key words: DEET, IR3535, picaridin, mortality, excito-repellency Mosquito-borne diseases are important public health issues globally, particularly in tropical and subtropical areas with limited means of prevention. Among the most successful tools for minimizing the transmission risk of diseases like malaria and dengue fever has been the use of various forms of vector control. Chemical control using synthetic chemicals remains a common and useful means of reducing pathogen transmission and protection from mosquito bites. However, this approach has had several drawbacks, including recur- ring high costs, being labor intensive, the development of chemical resistance in target vector populations, and the possibility of unin- tentional environmental contamination adversely impacting nontar- get organisms. The routine application of chemicals has inevitably led to the selection of numerous insecticide-resistant mosquito popu- lations and species worldwide (including Thailand), thereby VC The Authors 2017. Published by Oxford University Press on behalf of Entomological Society of America. All rights reserved. For Permissions, please email: journals.permissions@oup.com 1312 Journal of Medical Entomology, 54(5), 2017, 1312–1322 doi: 10.1093/jme/tjx081 Advance Access Publication Date: 15 April 2017 Research article Downloaded from https://academic.oup.com/jme/article/54/5/1312/3737816 by guest on 05 February 2023