County mosquito plan laid out for city council

County crews will return to Columbia Falls this spring for mosquito control work, but the focus will be on mosquitos in the larval stage, not adults, Flathead County public health officer Joe Russell told the Columbia Falls City Council on March 19.

Last year marked a big change, Russell said, when city manager Susan Nicosia persuaded him to direct county crews to spray for adult mosquitos.

“Last year was a phenomenal year for mosquitos,” Russell said. “But we’re not the Milk River area.”

The goals of the county’s mosquito control program are first, to protect residents from mosquito-borne diseases such as West Nile virus, and second, to reduce the impact of nuisance mosquitos.

To keep ahead of the problem, efforts should be directed against mosquitos in the larval stage, Russell said. That begins with property owners cleaning up old tires, hub caps, wading pools and anything else that holds standing water.

The next step is application of larvacide, but county personnel must first confirm a problem exists by surveying areas to identify probable breeding habitats and measure production levels. Most surveillance visits result from complaint calls by the public.

Larva control is considered the most effective way to reduce mosquito populations. Larvicides currently in use by Flathead County include bacillus thuringiensis, a naturally occurring soil bacterium; Altosid, a product containing methoprene, a compound that mimics an insect growth hormone; and Agnique, an extremely light oil that prevents mosquito larva from breathing in water.

Mosquitos don’t breed in fast-moving water, such as Flathead River, or in sloughs with steep banks, Russell said. They tend to breed in slack water with feathered banks, where the water’s rise and fall leaves dry ground for larva to adhere to. Mosquitos don’t breed in tall grass but harbor there, so keeping grass mowed will help, he said.

When it comes to treating adults by spraying, the county is committed to using only EPA-approved products in accordance with state and federal regulations. Spraying was delayed last year because wind and other conditions were not right.

“We won’t jeopardize our program by doing it wrong,” Russell said.

Nicosia noted that residents in Mosquito Flats were thankful after the county sprayed for adults, but she emphasized that it was done safely.

“Personnel talk to all the neighbors and don’t spray where people don’t want it,” she said. “There was some private spraying last year, which we don’t have control over.”

“We use only safe chemicals — not malathion,” Russell said, noting that more education is needed for residents who apply incorrect amounts of insecticides.

Nicosia said mosquito information will be provided in the city newsletter which will come out in May. For more information, visit online at http://flathead.mt.gov/mosquitoes.

Russell also addressed the council’s questions about air quality. Mayor Don Barnhart, councilor Mike Shepard and Nicosia cited dust problems at the north end of town, along Truck Route and at the bark plant. Councilor Shawn Bates said bark piles caught on fire 17 times last year. Russell said their requests for investigations and to expand the existing air quality district boundary were “doable.”