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Battle against phragmites should help lower mosquito population at Utah Lake

By Kathryn May | Posted - Aug. 17, 2012 at 10:12 a.m.



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PROVO — The worst outbreak of West Nile virus in nearly a decade has hit more than 30 states. At least 200 people have become ill from the virus and 10 have died.

In Utah, there's been one confirmed case of West Nile virus so far. Utah Lake is one area of the state with a lot of mosquitoes.

The Utah Lake Commission is battling a noxious weed that has taken over the shoreline of Utah Lake. By knocking the weed down, it hopes it can help lower the mosquito population in the area and allow more people to enjoy the lake.

What is phragmites?
Also known as common reed, Phragmites australis is a large, coarse, perennial grass often found in wetlands. Although scattered clumps of phragmites provide cover for small mammals and birds, it usually forms large, dense stands that provide little value for wildlife. This invasive species reduces the diversity of plant and wildlife species. Source: Maryland Department of Natural Resources Photo: Photograph: Joseph M. DiTomaso, University of California - Davis, Bugwood.org

Kent Hardcastle spends a lot of time at Utah Lake water skiing and camping. When the mosquitoes come out, he said, there’s no escaping them. “As the sun sets, they get really, really bad, very quickly.”

Cris Schulz, who runs the marina concessions at Utah Lake State Park, agrees mosquitoes can be a problem, especially in areas near the water and boat ramp. “When the sun goes down, we do get a mosquito swarm or two,” he said.

Phragmites are big part of the problem, said Reed Price, executive director of the Utah Lake Commission.

Phragmites can grow up to 15 feet tall and become very dense. It doesn’t provide very good wildlife habitat for most wildlife, but for insects, it’s kind of ideal.

“Because it grows so dense, it creates a stagnant water condition, and when mosquitoes get down there and lay their eggs, it’s just an ideal environment for them,” Reed said.

There are about 5,500 acres of phragmites along the shores of Utah Lake. The commission plans to completely get rid of them over the next 10 years. They’ve spent the past week spraying the weeds with a herbicide.

“We’ve sprayed over 1,500 acres on the north shore of Utah Lake, and between Utah Lake State Park to Provo Bay,” he said.


Getting rid of the super weed will not only cut back on the mosquito population, it will also improve the wildlife habitat and restore beaches that can once again be used for recreation.

Over the last four years, the commission has treated approximately 30 percent of the shoreline. It hopes to remove it from the lake within 10 years. Treating an area can take several years. During the first year, the treatment kills about 80 percent of the weeds. Twenty percent of the weeds come back the next year. They treat that 20 percent and remove the dead phragmites from the previous treatment. Even after the second treatment, they still get some patches of weeds that pop up.

Getting rid of the super weed will not only cut back on the mosquito population, it will also improve the wildlife habitat and restore beaches that can once again be used for recreation.

A lot of people don’t know the lake exists, Reed said, because when they are close to it, they can’t see it because phragmites have taken over.

“When we open the shoreline up and people see that they can access the lake, they’ll begin to use it more,” Reed said.

Until that happens, Schulz said, “As long as you use good protection, put on DEET protection and ... it’s no problem.”

Contributing: Viviane Vo-Duc

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Kathryn May

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