This story has been updated with a new time for the treatment.

LAKEPORT, Calif. — In an effort to reduce the number of biting adult mosquitoes emerging this spring, the Lake County Vector Control District will be making an aerial treatment to the marshlands adjacent to the lake between Clear Lake State Park and Lakeport, parts of Anderson Marsh State Park, a small section east of the Clearlake Keys, and a small area near Bridge Arbor South in north Lakeport.

The treatment originally was expected to occur during daylight hours on Friday, Feb. 21. However, that morning, Vector Control said it has been rescheduled to Tuesday, Feb. 25.

The application date and any subsequent changes will be posted on the district’s website.

The application is being made because the district’s winter mosquito surveillance program has detected large numbers of mosquito larvae in the marshlands along the perimeter of the lake that flooded as the lake rose due to the abundant rains.

These mosquito larvae are an early-season floodwater species (Aedes increpitus) that hatch from eggs laid in the mud in previous years as the lake receded. When winter rains flooded the eggs, the larvae hatched and began developing in the still, shallow water.

As temperatures and day length increase in early spring, the Ae. increpitus mosquito larvae will pupate and then emerge as biting adults.

These mosquitoes are the aggressive biters experienced every spring by people living and recreating near this area.

The majority of applications will be made by a yellow crop duster flying at a low altitude over these marshy areas. Some of the marshy areas are near homes, and people may experience a brief noise nuisance from the plane. Additional applications to small areas using a drone are planned in late February or early March. Updates will be posted to the District’s website.

The product applied will be VectoBac GS, a biological larvicide used to control mosquito larvae in aquatic habitats. VectoBac is manufactured by Valent BioSciences, and is based on the naturally occurring soil bacterium, Bacillus thuringiensis israelensis, or Bti.

Vector Control called the VectoBac a “highly effective and economical microbial insecticide” that’s registered with the Environmental Protection Agency for the control of larval mosquitoes in nearly all aquatic habitats.

“Bti is highly selective for the control of mosquito larvae in water and does not affect plants, animals, or beneficial insects that live in or drink the water. The formulation is a biodegradable solid corncob granule coated with Bti. The Bti breaks down rapidly in nature so there is no persistence of the active ingredient. The use of a solid formulation reduces the possibility of drift onto adjacent property,” Vector Control reported.

The Lake County Vector Control District makes every effort to use the safest product available to minimize any health concerns the public may have.

The VectoBac GS label and the Safety Data Sheet are available from the Lake County Vector Control District’s website http://www.lcvcd.org/ or may be requested by calling 707-263-4770.

For more information about the Lake County Vector Control District and its services, please visit our website www.LCVCD.org. 

For information about West Nile virus, visit http://westnile.ca.gov/. 

Information about mosquito repellents can be found on the US Centers for Disease Control and Prevention website at http://www.cdc.gov/westnile/faq/repellent.html.