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Maine’s black fly season is now all summer long

Blackfly season now lasts all summer in Maine thanks in large part to improvements to the state's water quality.
Griffin Dill
via BDN
Blackfly season now lasts all summer in Maine thanks in large part to improvements to the state's water quality.

Nothing ruins a perfect Maine summer day faster than clouds of biting insects. Anyone who has spent any time here from May to October knows this and awaits their arrival with equal dread and stoic resignation.

From Kittery to Fort Kent, black flies, mosquitos, midges, deer flies and houseflies are the constant and unwelcome guests at any outdoor activity.

And while someone every summer will claim it’s the worst bug season yet, there is scientific evidence to back up the claim this year as experts point to factors such as clean water legislation and climate change.

“We used to have a ‘season’ for black flies,” said Jim Dill, pest management specialist at University of Maine Cooperative Extension. “Into the [1980s] it was from the end of May into the first couple weeks of June and then they would die off.”

Back then there were two species of black flies found in Maine. Since then, that number has grown to more than 40, though not all feast on human blood.

“Those two species did well in Maine because of how badly our waters were polluted,” Dill said. “Because [Senator] Ed Muskie stepped up and helped the Clean Water Act come into fruition, we started getting cleaner and cleaner water so more species of black flies could survive and reproduce here.”

Black flies need clean, fresh running water to reproduce. Muskie’s landmark 1972 legislation made dumping pollutants into rivers illegal, set wastewater standards and funded sewage treatment plants across the country.

It’s doubtful the Maine senator envisioned the law would also benefit the very insects that drove his constituents nuts in the Maine woods.

It also eliminated the weeks-long black fly season.

“As soon as the weather gets nice until the first frost you have black flies,” Dill said. “You have different species active at different times, but they are out there.”

At their worst, black flies swarm in clouds around warm-blooded mammals with the female of the species out looking to dine on that blood. The males feed on flower nectar. They are small, black or gray with short legs and very short antennae.

“They are horrible in Wallagrass,” Kate Novak said. “The back of my neck is like a mountain range of black fly bites mixed in with mosquito bites.”

Maine is now somewhat notorious for its black fly population. Over the years different towns around the state have held festivals, dances and other events to pay a tongue-and-cheek homage to the nuisance pest.

Not every biting insect in Maine likes clean water, though, according to Dill. Mosquitos and the larger deer or moose flies breed in stagnant pools or soggy areas.

“It only takes a couple of tablespoons [of water] for mosquitoes to breed,” Dill said. “This year we have gotten plenty of rain so I tell people to make sure they clean out garden buckets, their gutters and empty anything that has standing water in it.”

Even then, they will find a way. Maine has a mosquito called the “tree hole mosquito” that lays its eggs in water-filled holes or depression in trees.

“We have 40-plus mosquito species in the state,” Dill said. “And they will travel a mile or more from where they hatch in search of a blood meal.”

With the amount of rain the state has already received, Dill said it’s shaping up to be a good year for mosquito populations in terms of sheer numbers and breeding opportunities.

“We are going to have them all summer long,” he said.

All that rain is also good news for the 50 or so species of deer flies in Maine who need soggy, wet areas to breed.

Also called moose flies, these biting insects are recognizable by their distinctive large eyes with gold or green patterns and the dark bands across their deltoid-shaped wings. Their bite is often quite painful and they will circle endlessly around a person’s head waiting to strike.

“I’ve lived here more than 25 years and this is the worst I have ever seen the deer flies,” said Heather Russell of Waldoboro. “I try to go for a walk and they end up getting tangled in my hair.”

Russell said she’s taken to bringing a shirt with her to wave around to scatter the pests.

Conditions have also been right this year in certain parts of the state for entirely different kinds of insects to overlap.

Covering up and using natural or chemical bug repellent are the best way to deal with Maine’s biting insects, according to Dill.

“When doing outdoor work I have to cover myself from head to toe to avoid black flies, mosquitos, ticks and deer flies,” said Teresa Montague in Clifton. “There are times of day when the bugs are not as aggressive but of course warm, wet weather brings them out all day.”

This story appears through a partnership with the Bangor Daily News.