What you can do to protect yourself from the painful bite of deer flies

  • This collection of deerflies was caught on a hat patch worn by Mont Vernon, N.H., resident Lou Springer in July 2019.  Lou Springer – courtesy

Monitor staff
Published: 7/20/2019 6:20:32 PM

Between ticks, mosquitoes and black flies, New Hampshire has no shortage of infamous biting bugs. Recently, however, it seems that deer flies have taken center stage.

“They’re brutal,” said Deb Koltookian, co-owner of Outdoor Sports Center in Concord. “When I drive into my driveway, they swarm the car. I’m afraid to get out!”

Deerflies are part of the Tabanidae family, which includes equally unpleasant horseflies and greenheads. Like most biting insects, only the females drill into you with their saw-toothed proboscis, seeking a quick blood meal to develop their eggs.

Judging from many social media comments and the experience of this reporter, they seem particularly bad this year. But nobody tallies bug population statistics over time, so it’s hard to say.

“They are certainly out right now. I’m bothered by them every time I go for a morning run,” wrote Piera Siegert, the state entomologist. “However, I don’t notice that they are any worse this year than in prior years.”

Still, she added, “Larvae do generally tend to develop in mud, and we have had a couple of wetter years recently, which may mean that more deer flies have survived to adulthood.”

Deer flies are attracted to movement, which is why they swarm cars pulling to a stop, and to certain darker colors, especially blue. They also concentrate on the highest part of an object.

That last habit can be used as a defense, said Ethan Belair, the Hillsborough County Extension forester.

“If you can have something that’s taller than you, they’ll go to that. ... If I’m walking through the woods and I stop, to talk to the landowner, I’ll take off my baseball cat and hold it up in the air. They swarm to the hat, not my head,” he said.

Does that work? “Well – at least they’re not flying into my mouth and eyes.”

Belair said in Scouting days the idea was to grab a fern and put it in your hat, so the flies would be attracted to the waving object over your head.

“I used to work with a guy who put a dark-colored pinwheel stuck through the band of his cap. He swore they go to the movement and the taller object and leave him alone,” he said.

There’s a more drastic anti-deerfly method that involves turning the top of your head into a trap.

Several companies sell very sticky patches that can be placed on the back of a cap or hat; when the flies touch down they are trapped. Judging from comments of people who have tried them, they can reduce but not eliminate the problem as you walk along.

A more informal version involves spreading the ultra-sticky compound called Tanglefoot onto something disposable – a plastic cup is common – that you attach to the top of your hat when heading outdoors.

It works, in the sense of snagging and killing some flies, but it doesn’t protect you entirely, as this reporter confirmed in his own yard.

It also has drawbacks. For one, you have to remember to duck when walking underneath branches; for another, when making the device it’s almost impossible to not get Tanglefoot on yourself or the hat or the kitchen counter or somewhere else that you don’t want to be really, really sticky.

There’s one other idea which came up from a reader responding to an article in New Hampshrie-based Northern Woodlands magazine. In Nova Scotia, the reader said, people build pretend dragonflies out of bobby pins, colored foam and green string, and attach them to their hat. Because dragonflies are natural predators of flies, the readers wrote: “A pair of these work wonders; all you have to do is turn your head a little so the deer fly can see the dragonfly, and they veer off like a jet aircraft avoiding ground to air missiles. No killing required.”

And then there’s always the final response: Grin and bear it.

Belair said that in the woods he wears long sleeves and pants, treats clothing with permethrin to keep off ticks, and dons various insect repellents. But in the end, a certain level of stiff-upper-lip is needed.

“The way a lot of people who work outdoors end up viewing insects in general is: They’re always going to be an issue,” he said. “I try not to notice them as much as I can.”

David Brooks bio photo

David Brooks is a reporter and the writer of the sci/tech column Granite Geek and blog granitegeek.org, as well as moderator of Science Cafe Concord events. After obtaining a bachelor’s degree in mathematics he became a newspaperman, working in Virginia and Tennessee before spending 28 years at the Nashua Telegraph . He joined the Monitor in 2015.

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