|Barnard, Donald - Don|
Submitted to: American Mosquito Control Association
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 6/16/2003
Publication Date: 9/1/2003
Citation: Xue, R., Barnard, D.R., Ali, A. 2003. Laboratory evaluation of eighteen repellent compounds as oviposition deterrents of aedes albopictus and as larvicides of aedes aegypti, anopheles quadrimaculatus, and culex quinquefasciatus. American Mosquito Control Association. Interpretive Summary: Mosquito vectors transmit disease agents that cause sickness and death in humans and animals. Control of the vector is the best way to prevent outbreaks of mosquito-borne disease; furthermore, it is more efficient and effective for this purpose to control immature mosquitoes (eggs, larvae, pupae) than it is to control adult mosquitoes. Scientists at the Center for Medical, Agricultural, and Veterinary Entomology in Gainesville, FL in cooperation with scientists at the University of Florida. have identified several chemicals (normally used as topical mosquito repellents) that prevent egg-laying (oviposition) by female mosquitoes and that kill mosquito larvae in the aquatic habitat. These repellents were found to be effective oviposition deterrents and larvicides against the mosquitoes that transmit yellow fever, dengue, and West Nile viruses and malaria. Although the repellents are too expensive to use for area-wide mosquito control, they may be effective under other circumstances, such as for the control of container-inhabiting mosquitoes in urban and suburban environments.
Technical Abstract: Twelve of the 18 repellent compounds evaluated in the laboratory for repellency against ovipositing Aedes albopictus showed significant repellency. The ED50 values of these compounds against ovipositing mosquitoes ranged from 0.005% to 0.052%. Toxicity of the 18 compounds to the 4th instar larva of Anopheles quadrimaculatus, Culex qinquefasciatus, and Aedes aegypti was evaluated in the laboratory. Nine-12 of these compounds tested showed significant toxicity although the mortality data did not fit the linear model of the statistic analysis. After 24 and 48 h exposures to the compounds at the application rate used for ovipositional repellency, 12 compounds induced 67-100% of mortality of the 4th instar larvae of An. quadrimaculatus. Nine compounds induced 74-100% of larval mortality of Cx. quniquefasciatus and 10 compounds induced 55-100% of larval mortality of Ae. aegypti. A multiple way analysis for the mortality data showed that the compounds, application rates, mosquito species, and exposure times affect the percentage of larval mortality.