Submitted to: Medical and Veterinary Entomology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 6/25/2001
Publication Date: N/A
Interpretive Summary: Insect repellents intended for application on skin are not normally evaluated for other kinds of biological activity. However, when scientists at the ARS Center for Medical, Agricultural, and Veterinary Entomology in Gainesville, Florida and the University of Florida tested the mosquito repellent deet and two experimental repellents in the laboratory they found dthat the repellent-treated water in bioassay containers killed mosquito larvae for a long as 6 months. Subsequently, in tests of the larvicidal activity of each repellent under field conditions, one experimental repellent killed mosquito larvae for up to 6 weeks. Based on the results of the field study, it was concluded that oviposition repellents could be useful for mosquito control under certain circumstances. For example, in urban/suburban environments, where container inhabiting mosquitoes abound, repellent-treated containers could be strategically placed to direct gravid dfemales from their normal oviposition sites to attractant-enhanced lethal ovitraps that would trap and kill them.
Technical Abstract: Toxicity and persistence of the skin repellents AI3-37220, AI3-35765, and deet (N, N-diethyl-3-methylbenzamide) were evaluated as larvicides against Anopheles albimanus and Aedes albopictus in the laboratory and Ae. albopictus in the field. The LC 50 of AI3-37220, AI3-35765 and deet ranged from 0.005 percent to 0.021 percent for 1st-instars and from 0.015 percent to 0.034 percent for 4th-instars of Ae. albopictus and An. albimanus. In laboratory tests, 0.1 percent AI3-37220 killed greater than 90 percent of 1st-instars of both species for 32-34 weeks and 4th-instars of Ae. albopictus and An. albimanus for 14.3 weeks and 6.3 weeks, respectively. AI3-35765 at 0.1 percent killed greater than 90 percent of 1st-instar Ae. albopictus and An. albimanus for 13 weeks and 4 weeks, respectively and 4th-instars of both species for 2.7 weeks. Deet at 0.1 percent killed greater than 90 percent of 1st-instar Ae. albopictus for 3.7 weeks and An. albimanus for 3 weeks, and 4th- instars of both species for 1 day. In field tests, in artificial containers, AI3-37220 provided complete control of Ae. albopictus larvae for 9 weeks, AI3-35765 for 6 weeks, and deet for 1-2 weeks. In used tires, AI3-37220, AI3-35765, and deet provided complete larval control for 5, 5, and 2 weeks, respectively. In cemetery vases, AI3-37220, AI3-35765, and deet provided 100 percent larval control for 6, 6, and 4 weeks, respectively.