Despite Soggy Spring, Experts Say Jury’s Out On Huge Mosquito Season For Wyoming

Many parts of Wyoming have become waterlogged this spring, but experts say it’s still too early to tell whether that means we’re in for a terrible mosquito season.

June 19, 20233 min read

Mosquito swarm 6 19 23
(Getty Images)

Many parts of Wyoming have become waterlogged this spring, but experts say it’s still too early to tell whether that means we’re in for a terrible mosquito season.

Laramie City Parks Manager Scott Hunter told Cowboy State Daily the number of mosquitoes showing up in traps so far is normal.

“West of Laramie in places where we normally see flooding, the trap numbers aren’t exceptionally high,” he said. “It might be because of the cool spring.”

Laramie’s Mosquito Control Supervisor Hunter Deerman said he’s expecting normal mosquito pressure, although mosquitoes that carry West Nile virus don’t normally start showing up until late July.

“The weather data here looks similar to the last few years and the river isn’t running a lot higher,” he said. “We are expecting the same trend with mosquito numbers.”

That also could mean an itchy time for the Cowboy State, as mosquito eggs can lay dormant for years and last summer was a perfect breeding ground for skeeters.

A University of Wyoming entomologist told Cowboy State Daily then that most of the mosquitoes in Wyoming are “floodwater mosquitoes,” which means they will stay dormant as eggs waiting for flood events.

Plenty Of Hatching Pools

Most recent precipitation for June shows above-average rainfall in most places around Wyoming.

According to the National Weather Service, Big Piney is about an inch above normal for the month of June. Buffalo is close to 4 inches above normal. Casper is about 2 inches above normal for June, while Lander and Worland are just under 2 inches above normal for the month.

Laramie treats 77,000 acres of ranchland near the city each year. Deerman said plans are to spray an aerial treatment of larvicide in early July when mosquito populations peak. Larvacide kills all mosquitoes, he said.

A Health Concern

West Nile Virus has been found in every county in Wyoming, according to the Wyoming Department of Health.

Deerman, who also is a mosquito biologist, said West Nile is the major concern with the insects, and that the disease is trending down in recent years.

He tests individual mosquitoes every summer as part of a surveillance program looking for the culex species that carries the disease. They typically show up in late July.

“We test mosquitoes, and we can usually find it before it shows up in other hosts like horses,” he said.

Hunter said Laramie residents can expect to see more mosquitoes once farmers start knocking down meadow hay in a few weeks.

The Wyoming Department of Health advises people to reduce risk of West Nile Virus by using insect repellant and wearing protective clothing.

About one in five people infected with the disease will develop a fever with other symptoms. Less than one percent of people infected develop a serious, sometimes fatal neurologic illness.