The Santa Clara County Vector Control District will spray the skies over Palo Alto with insecticides on Wednesday in an ongoing effort to get rid mosquitoes, which are an increasing problem with the recent winter rains.
The treatment is scheduled to start at approximately at 7:30 a.m. in the Palo Alto marsh areas and may continue in the afternoon. If needed, the operation may be extended to to Thursday.
The helicopter may make low-altitude passes over trails surrounding the treatment area, so the public is advised to avoid areas where the helicopter is operating.
Commonly called the “winter salt marsh mosquito,” Aedes squamiger lays its eggs in the moist soil in late spring and early summer. These eggs can lay dormant for many years, even after repeated flooding. High tides and seasonal rains, together with the short days and cooler temperatures of winter, cause the eggs to hatch as early as November. This species is known to bite viciously during the day and can fly over 15 miles from its breeding grounds to feed on humans and other mammals.
These mosquitoes are known for biting during the daytime rather than dawn and dusk. They are known carriers of viruses like West Nile and Dengue, though not the Zika virus, according to the California Dept. of Public Health. The type of mosquitoes that carry Zika are not native to the United States, though they have been found in California, including in Hayward, Menlo Park and Atherton in the Bay Area. None has tested positive for Zika.
If left untreated, a significant number of salt march mosquitoes will likely become adults in early to mid-March, based on current data. The mosquito fly-off may affect residents from the north coastal areas of the county to as far south as the southernmost part of the city of San José and east to Milpitas. The aerial treatment is intended to minimize the number of mosquitoes and reduce the risk of mosquito bites to residents in the surrounding communities, according to the district.
The vector control district said that about 725 acres will be treated with water-based formulations of what they are calling environmentally safe products: methoprene, an insect growth regulator, and Bacillus thuringiensis var. israelensis. To learn more about the type of insecticides, click here.
For more information about mosquito prevention, go to SCCvector.org or call (408) 918-4770.