Black fly/gnat

Lots of rain and high water have helped make boost this spring’s black fly population in Minnesota. (Image courtesy of the Illinois Department of health)

If you’ve spent much time outdoors this spring, you probably know the feeling of a gnat bite.

It starts when a female biting gnat cuts a small chunk of skin from its victim. Then the small black fly feeds on the blood that seeps into the newly formed hole.

“They also have an anticoagulant that they dribble into that little hole they’ve made, and so that’s what causes the really intense reaction,” said Mike McClean of the Metropolitan Mosquito Control District.

While these gnats don’t carry any diseases that can transmit to humans, Minnesotans have experienced the annoyance of an especially large gnat population this season.

Most people would simply call them “gnats.” But Minnesota is home to four kinds of biting gnats, or black flies. This year’s most prevalent pest is known as the buffalo gnat.

They’re closely related to mosquitoes, McClean said, “but they’re tougher.”

Mosquito repellent keeps gnats at bay, too. But miss a spot of skin and they aren’t as forgiving as mosquitoes.

“Black files are a little bit more aggressive and they’ll go for those uncovered parts of your body,” McClean said. “If you miss a spot with the repellent there, they’re likely to find it.”

Minnesota’s clean and abundant water is good for buffalo gnats. Their larvae hatches in it and they filter feed from water, too.

Plus, widespread flooding across Minnesota has made treatment difficult or impossible in many areas.

Relief on the horizon?

However, McClean said Minnesotans could see some relief from the pests even in the next few days.

Gnats have a short life cycle. Even a windy day can help clear them from the air, McClean said.

Plus, the MMCD has been able to start some treatments. McClean said workers already did some treatments on the Mississippi River at the Coon Rapids Dam.

For now, keep the bug spray and vanilla handy.

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