Area-wide larviciding using truck-mounted low-volume technology will be among the recommendations from a five-year, $3.8 million U.S. Department of Agriculture project to control the Asian tiger mosquito, Aedes albopictus. The project, run by Mercer and Monmouth Counties in New Jersey and Rutgers University, is the first nationally funded area-wide USDA mosquito program.
When the mosquitoes (carriers of West Nile virus, dengue fever, yellow fever, and chikungunya virus, which causes an illness similar to dengue) became a public health issue, Superintendent for Mercer County Mosquito Control Ary Farajollahi and his team joined forces with Rutgers University.
“We are working to determine the most economic and efficacious means of controlling this mosquito, which includes the biology, the ecology and the most appropriate pesticides to use against this species. We’re also working to develop new equipment, new technology — every aspect that affects control and surveillance of the species. Final recommendations will be issued in 2013, along with a website and pamphlet detailing the guidelines to combat Aedes albopictus,” he explains.
Aedes albopictus mosquitoes first appeared in Texas in 1985, but the invasive pest is native to the tropical and sub-tropical regions of Southeast Asia. They were originally transported to the United States in used tires, and then appeared in New Jersey 10 years later; initially in Monmouth County, east of Mercer County. As of late August, all counties in New Jersey had seen infestations, and the mosquitoes have spread to New York State and New York City.
“At first we didn’t control the mosquitoes as aggressively as we should have. And as a result of the mild winters in the early 2000s, the mosquitoes continued to spread. The cold winters had previously kept the species in control, but milder winters resulted in larger numbers surviving,” Farajollahi points out.
“The reason why Aedes albopictus mosquitoes are such a headache for us is that they are container-inhabiting. They’re not like saltwater or floodwater mosquitoes or other species, which we’re very good at controlling. After a rain event, we know which habitats flood so we can respond operationally to these habitats and intervene with appropriate control measures.” But this species thrives in small containers like buckets in residential backyards, which makes access for mosquito inspectors difficult. Farajollahi cites an example of a 100-acre residential site of 1,000 individual residences, which would require 10 inspectors and two weeks to control.
Using one of the new technologies developed from the project, low-volume truck sprayers, a team can dispense a larvicide in two hours on an area-wide basis requiring only two inspectors. This approach is less labor-intensive and more economical.
“The low-volume sprayer has slightly higher droplet sizes and dispenses a larvicide, VBC’s VectoBac® WDG, so we’re essentially creating small artificial drops of rain. The droplets that go out from the sprayer eventually land in containers. When they land, they contain a larvicide, a bacterial biorational pesticide. The droplets mimic rain; they collect and settle down in containers.”
Mercer County will continue testing during the final year of the project. In the meantime, the use of truck-mounted low-volume technology dispensing a larvicide on an area-wide basis is also being rolled out to other vector control programs. Standard operating procedures for this method are available to any operation that has interest. Other states as well, including Louisiana, California, Pennsylvania and New York, are utilizing the technologies being developed by the teams in New Jersey.
“When we deal with mosquito control in Mercer County, we use integrated management and don’t limit ourselves to any one means. The area-wide larvicide application using VectoBac® WDG is certainly one approach. We also are using other larvicides, adulticides, public education and source reduction,” Farajollahi points out.