Prince William County has been testing and spraying for mosquitoes.
According to a release, individuals from the Prince William County Public Works Department’s Mosquito and Forest Pest Management Branch have been testing mosquitoes in the area to see if they are infected with the West Nile virus.
When the branch finds a cluster of mosquitoes that are infected, they begin spraying to kill the infected mosquitoes.
The spraying occurs typically during the week between June and the end of September when needed, according to a release.
The branch will also come to Prince William homes and complete free mosquito sire inspections to help prevent breeding on the resident’s property. Residents can call for the service at 703-792-6279.
More on the county’s mosquito spraying, from a release:
Rachel Kempf, a Mosquito and Forest Pest Management specialist with the county, said fogging trucks generally spray after dark when most people are inside and mosquitos are most active. “We spray in the evenings after sunset and will sometimes go until 12 or 1 a.m. depending on how many spray blocks are scheduled.”
The spray is a synthetic pyrethroid, which is a common pesticide that mimics the natural pyrethrum derived from the chrysanthemum plant. The spray has very little residual activity, due to rapid degradation in sunlight.
While the spray is considered a low toxicity pesticide, Kempf says that it is always prudent for citizens and their pets to stay indoors while the trucks are conducting spray operations. “The risk is low with proper application, but contact with the spray can lead to minor eye and skin irritation. As a precaution, bring pets and their food and water dishes, as well as children’s toys and clothing inside, and avoid contact with wet surfaces until they have completely dried, around one hour post spray. If the spray ends up in your eyes or on your skin, flush immediately with water.”
To determine where to spray, specialists from the pest management branch trap adult mosquitos and send them to George Mason University for a DNA amplification test, which determines if West Nile Virus was present in that pool of mosquitos.
An area will typically be treated once during the season, unless the traps indicate more spraying is needed, said Kempf. “We spray only in response to West Nile Virus positive mosquito pools. Some areas of the county will not be sprayed, and some areas will be sprayed more than once over the course of the summer, depending on what we find in our adult traps.”
It is important to note that while Mosquito and Forest Pest Management continually manages mosquito populations from April through October by treating for mosquito larvae, populations of adult mosquitoes can still rise and become infected with diseases in certain areas. Therefore, Kempf said people should take precautions to knock out the places mosquitos breed. “Mosquitos tend to breed in stagnant streambeds, ditches, that kind of thing, but they also breed in containers. So, it’s important for homeowners to go out and check their property for any amount of standing water. Mosquitos can breed in as little as a quarter-inch of water.”