2012 Annual Report
1a.Objectives (from AD-416):
Evaluate the ability of insecticide-treated materials to kill mosquitoes indoors over extended periods of time.
In Phase II will determine the bioefficacy of treated Durable Lining (DL) in huts in which the walls are partially covered.
1b.Approach (from AD-416):
Insecticide-treated wall linings will be placed on the inner walls of small, wooden huts. Bioassay tests will be conducted in these huts with three genera of laboratory-reared mosquitoes on a weekly basis. Some wall linings will be subjected to simulated weathering conditions before being tested.
In Phase II the same five huts located on CMAVE property that were used in Phase I of the project will be used. Three huts will remain covered as they were in Phase I; two completely covered with untreated DL and one completely covered with treated DL. Two additional huts will be utilized in which only half the wall space will be covered with treated DL. In one the top half will be covered and in the other the bottom half will be covered. Bioefficacy of these configurations will be determined in the same manner as outlined in Phase I: WHO cone tests and release of free flying mosquitoes of three species of colony reared insects. One modification will be that WHO cone tests will be conducted on both the covered and uncovered wall surfaces. Both bioassay techniques will be conducted on a monthly basis.
This project is related to Objective 2 of the in-house project - "Develop new application methods for pesticides to biting Nematocera that minimize environmental exposure and that optimize lethal or repellent effect, including presentation on clothing, aerosol application in or outdoors, residual application, disinsection of aircraft, and delivery of spatially repellent compounds."
The World Health Organization cone bioassay touch test was used to evaluate mosquito knockdown and mortality caused by the insecticide-treated durable wall lining against 3 mosquito species. A second test method, which utilized 100 free-flying female mosquitoes of each species, was also used. During the first year of the study all the walls of the huts were completely covered; this configuration resulted in 100% mortality with the cone test and approximately 90 percent reduction in trap captures in the treated versus control huts of the free-flying mosquitoes. Both of these results reflected the capability of the treated wall lining to kill mosquitoes for at least a year. After a year, half the wall lining was removed from the treated huts to see if the same level of control could be maintained with this configuration. After 9 months, results from both the cone free flying tests indicated the same level of control was achieved in the huts with only half the walls covered as when the walls were fully covered. Since this project began, ARS researchers at Gainesville, FL, met with Vestergaard-Frandsen personnel to review these results and discuss ongoing research at various meetings and at the ARS Center for Medical, Agricultural and Veterinary Entomology in Gainesville, FL. Progress was monitored through meetings, telephone calls, and e-mails.