SURVEILLANCE AND ECOLOGY OF MOSQUITO, BITING AND FILTH BREEDING INSECTS
Location: Mosquito and Fly Research Unit
Title: Susceptibility of mosquitoes to insecticides in a liquid sucrose bait
Submitted to: Journal of Vector Ecology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: August 23, 2010
Publication Date: June 1, 2011
Citation: Allan, S.A. 2011. Susceptibility of mosquitoes to insecticides in a liquid sucrose bait. Journal of Vector Ecology. 36(1):59-67.
Interpretive Summary: Mosquitoes pose very serious medical and agricultural threats because of their nuisance status and role as vectors of malaria, dengue, yellow fever, West Nile virus and other arboviruses. Control is often challenging because of insecticide resistance, non-target and environmental concerns, and difficulty in targeting the mosquitoes for treatment. In this study, conducted at USDAs Center for Medical, Agricultural and Veterinary Entomology (CMAVE) laboratory in Gainesville (Florida), a control approach combining insecticides with the natural sugar-seeking behavior of mosquitoes was examined. Insecticides were combined with a sucrose solution and evaluated as oral toxicants against three species of mosquitoes. Several compounds from different classes of insecticide were very toxic against all mosquito species and these compounds can form the basis for a novel approach for targeted control of mosquitoes.
Mosquitoes characteristically feed on plant-derived carbohydrates and honeydew just after emergence and intermittently during their lives. Development of toxic baits focusing on this carbohydrate-seeking behavior may potentially contribute to localized control. In the present study, ten insecticides were fed to female Culex quinquefasciatus, Anopheles quadrimaculatus and Aedes taeniorhynchus in a 10% sucrose solution. Active ingredients representative of five classes of insecticides (pyrethroids, phenylpyroles, pyrroles, neonicotinoids, and macrocyclic lactones) were selected for comparison with commercial formulations used to facilitate incorporation of active ingredients into aqueous sucrose solutions. Sucrose as a phagostimulant significantly enhanced mortality to toxicants. In general, the most effective active ingredients were fipronil, deltamethrin and imidacloprid, followed by spinosad, thiamethoxam, bifenthrin, permethrin and cyfluthrin. The least effective ingredients were chlorfenapyr and ivermectin. For some of the ingredients tested, Cx. quinquefasciatus was the least susceptible species. One-day-old male Cx. quinquefasciatus were more susceptible than females; however, no differences existed between one- and seven-day-old mosquitoes. There were no differences in susceptibility between unfed and gravid 10-day old female Cx. quinquefasciatus to bifenthrin. In conclusion, several pesticides from different classes of compounds have potential for use in development of toxic baits for mosquitoes.