Mosquito season about to begin in Tahoe-Truckee

By Kathryn Reed

Get out the bug spray – mosquito season is likely to be pretty bad in the Tahoe-Truckee area.

“I would definitely say that with a snowpack this year that is more typical of what winter up here should look like, that we are anticipating a more typical mosquito season, which will feel like increased numbers compared to the last handful of drought years,” Angella Falco, field station manager in Tahoe for Placer Mosquito & Vector Control District, told Lake Tahoe News.

Mosquito larvae was evident in late April in Placer County with ponding water in various locations.

“This is going to be a bad year for mosquitoes, so we all have to work together. First and foremost, dump any standing water or any objects that can trap or collect water,” Krista Jenkins, district manager for Douglas County Mosquito Abatement District, told Lake Tahoe News. “Mosquitoes can breed in small amounts of water like planters, bottle caps, tires, buckets and etc.”

The district was formed in 1969 at which time the Lake Tahoe and Topaz areas of Douglas County were and still are not included. When the West Nile virus hit Douglas County in 2005, the district and Douglas County signed an agreement for services. That contract ends this fiscal year.

Standing water is where mosquitoes like to breed. Photo/Kathryn Reed

Normally mosquito breeding sites in Douglas County are monitored starting April 1. The long winter didn’t allow that to happen.

“Temperatures of both the air and the water play a big role in how the larvae stages advance. The cooler the temperature, the longer it takes the larvae to mature into flying adults, which is a good thing for us,” Jenkins said. “We cannot treat running water. When the water stops flowing and settles in the low areas or accumulates into catch basins, that is when our job begins. Emergence of the adults can happen from that point on. It all depends on the habitat of each breeding area.”

Vector control officials use what is considered an environmentally-friendly larvicide at Lake Tahoe. This is to prevent the larvae from hatching. If that doesn’t work, then an adulticide is used. This is a chemical that is released into the air.

“There are certain protocols to follow for this to happen and we are very strict about following them,” Jenkins said.

This month is when people throughout the Tahoe-Truckee area are bound to start noticing the pesky biting machines.

“With continued storms well into spring, it’s hard to estimate when adults will begin to emerge, but safe to say that mosquitoes will be found from mid- to late May, well into July based on the current snowpack,” Flaco said. “The lower elevations around the Lake Tahoe and Truckee areas will melt and produce first, and areas in and around the Soda Springs, Serene Lakes and Sugar Bowl areas producing in late spring.”

Residents are encouraged to call their county vector control office if standing water lingers, especially into the summer.

Dumping any water that has collected in containers is encouraged. This is to eliminate breeding zones. Mosquitoes can lay their eggs in the tiniest of areas.

Once they are hatched, mosquitoes are most active at dawn and the first two hours after sunset.

Authorities recommend applying insect repellent containing EPA-registered active ingredients such as DEET, Picaridin, IR3535, or oil of lemon eucalyptus to repel the insects. Wearing pants and long-sleeved shirts is also advised. Repairing torn window screens will keep the skeeters out.

Mosquitoes can carry the West Nile virus. In 2016, there were 442 confirmed cases of the virus in 30 counties throughout California, including one case in El Dorado County. Statewide there were 19 human deaths.

In the Carson Valley, there were three human cases of West Nile in 2016.

“We really have two mosquito seasons up here, snowmelt season with its handful of species, then changing over to our summer mosquitoes during the warm months,” Falco with Placer County said. “Our agency has an extensive surveillance program that includes assessing mosquito larvae and adult mosquito abundance in the spring through the summer. We do extensive treatment for mosquito larvae in snowmelt pools in the spring as well as catch-basin systems in the spring and summer. We also respond to reports of mosquitoes and dead birds. In the past several years of our enhanced surveillance in the Tahoe area, we have not found West Nile virus infected mosquitoes. Hopefully, this remains the case, but there’s no way to predict what the upcoming season may hold.”

Dogs and cats can become infected with West Nile virus, too, but they do not suffer the severe symptoms like humans, horses, and birds.

“We also trap mosquitoes on a regular basis to not only monitor the adult population, but to more importantly have the adult mosquitoes tested for the West Nile virus. This is also part of maintaining our protocols,” Jenkins said.