Nasty mosquitoes everywhere, even in October? Yes — but it appears that to prevent harming bees and other pollinators, we need to temper our mosquito-killing tendencies.

The subject emerged at this week's Washington County Board meeting when Commissioner Lisa Weik, who represents Woodbury, reported that residents who live near a golf course were asking for help to fight swarms of mosquitoes. Weik contacted the Metropolitan Mosquito Control District and asked that representatives meet with residents, which they did.

Commissioner Fran Miron, a farmer, said he understands the problem but advised caution in how it's addressed.

"As we treat mosquitoes, there's potential to harm pollinators," he said. "There's a balance that has to occur there."

Much of Washington County rallied to the pollinator cause recently when the National Park Service began recruiting partners to reverse a sharp decline in honeybees, monarch butterflies and other pollinators that produce our food. The Park Service oversees the St. Croix National Scenic Riverway, which stretches from Stillwater to the headwaters of the St. Croix and Namekagon rivers.

Mike McLean, of the mosquito district, acknowledged the difficult balancing act when spraying "to knock the mosquito population down to a manageable level." Some chemicals are toxic to bees, he said, and workers who spray try to avoid beekeepers' hives.

"We don't want to be in a position of accidentally harming them," McLean said. "If we avoid direct applications around hives and flowering plants, we'll minimize the effect on hives."

The main strategy for mosquito sprayers, metrowide, is to attack larvae before they hatch. That's become a particularly daunting challenge as incessant rain breeds more mosquitoes, McLean said.

Sprayers also pay attention to bald eagle nests, wildlife management areas and other sensitive places, he said. Pesticide applications in general can be a problem, but the Mosquito Control District wants to do its part in avoiding harm to pollinators, he said.

"We've done a lot of work trying to engage beekeepers," he said, such as learning their whereabouts before unknowingly spraying their hives. Many people use www.driftwatch.org, an online mapping tool that allows crop producers, beekeepers and pesticide applicators to share information, he said.

Laurie Schneider, of Pollinator Friendly Alliance in Stillwater, said honeybees provide a small percentage of overall pollination. The bigger concern, she said, is that mosquito spraying can kill prolific pollinators such as wild bees, beetles and butterflies.

A matter of convenience?

Tolerating mosquitoes for the short times they're bothersome, she said, would be a better course of action than spraying. One type of pesticide — pyrethrins — is particularly toxic to bees, she said.

"I think people really don't want to be inconvenienced," Schneider said. "Every time we kill something we affect something else in that ecological chain. We need to start doing more to accommodate our ecological balance."

McLean said it's a challenge to manage expectations in an urban environment with so many landscapes and variables such as differing amounts of rainfall.

The Mosquito Control District received as many as 5,000 phone calls this summer from metro residents, he said. But the chilly weather to come should end the invasion.

"For the most part, the annoying, human-biting mosquitoes get killed off with the first frost," McLean said.

Kevin Giles • 651-925-5037