How to Survive Black Fly Season in the Adirondacks

Categories: Northeast, Travel Tips

Post summary: How to avoid black flies during black fly season in the Adirondacks.

If you’ve spent any time in the Adirondacks in the spring or early summer, then you’re likely all too familiar with the tiniest, most irritating, blood sucker in the whole United States – the dreaded black fly. In fact, you’re probably groaning in agreement as you think back to the incessant buzzing hounding you for miles.

For those who aren’t quite as familiar, we’re not talking about the common housefly here. We’re talking about the black fly – also called the ‘buffalo gnat’ – that emerges every spring to wreak havoc on unprotected hikers, fishermen, and anyone else trying to enjoy time in nature.

These little blood suckers are, at best, about 0.5 inches long (about the size of an aphid), and they deliver a bite comparable to a bee sting.

LEFT: Black Fly larvae in river by GlacierNPS (CC PDM 1.0); RIGHT: Black fly/buffalo gnat biting skin by D. Sikes (CC BY-SA 2.0)

Here are a few of the best ways to keep Adirondack black flies at bay (keep reading for more):

  1. Avoid areas around fresh, running water
  2. Protect yourself by covering all exposed skin
  3. Use a good bug repellant containing DEET or essential oils such as peppermint, lemongrass, and lavender

If you’ve never had the pleasure of being swarmed by black flies, then it’s super easy to write them off as just a bit of an annoyance. But that’s a mistake you’re sure to only make once!

These little devils are nothing to take lightly. If you’re visiting the Adirondacks during the notorious “Black Fly Season”, it’s in your best interest to be mentally and physically prepared.

Here’s everything you need to know about surviving Black Fly Season in the Adirondacks

Adirondack Black Fly 101: Habitat, Description, and Lifecycle

Before we dive in to the details of surviving black fly season in the Adirondacks, it’s helpful to review a bit of “black fly 101”, to help better understand when and where they tend to hangout.

These little blood suckers are, at best, about 0.5 inches long – about the size of an aphid. They’re easily identifiable by their pointed rear, downward facing head, and humped back – hence the nickname ‘buffalo gnat’.

They’re semiaquatic insects, spending the majority of their lives in fresh, flowing water.

The life cycle of a black fly is about 40 days long (about 40 days too long, in my opinion). Over the course of their life, female black flies lay around 500 eggs, which hatch within about a week.

Lifecycle of a black fly or buffalo gnat

General life cycle of black flies. BLACK FLIES: BIOLOGY AND PUBLIC HEALTH RISK (Illustration by: Scott Charlesworth, Purdue University, based in part on Peterson, B.V., IN: Manual of Nearctic Diptera, Vol.1)

Once they hatch, the females set off in search of blood, in order to lay more eggs…and the seasonal Adirondack black fly torture begins.

The female black flies will travel up to 10 miles for a blood meal, which is when they’ll attack unprotected hikers, campers, fisherman, and anyone else who ventures into their territory.

When and where are black flies the worst in the Adirondacks?

Black flies are the worst in early spring, which runs from about mid-May to mid-July in the Adirondacks.

How bad the black flies are mostly depends on the time of day and on the weather. Black flies are generally most active a few hours after sunrise and just before sunset.

However, if the weather is humid and cloudy, the flies are at less of a risk of dehydrating during midday hours, so all rules go out the window and they will will hound you all day long.

Your only saving grace is that they can’t fly in wind. That goes for pretty much any wind. So if there’s a slight breeze, you should be fine…or at least better off.

Black flies tend to be the worst in areas with a lot of leaf litter and near moving water in heavily wooded areas, like rivers and streams. This is why you’re most likely to encounter them when you’re spending time in or near the woods.

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How do they even find humans, anyway?

If you’ve spent any time in the Adirondacks during black fly season, then you may be all too familiar with the “Adirondack Wave”, or the frantic waving and swatting of the air, often accompanied by a bit of a jog – or sometimes even a flat out sprint. It’s often used as a desperate attempt to keep black flies from landing and biting.

Because it seems no matter what you do or how quietly you walk, the little vampires always seem to find you with laser sharp accuracy almost immediately. And then they tell all of their friends.

I mean, how do they even find us so fast, anyway? Well, there are two ways:

  1. Carbon dioxide: Black flies are attracted to the cloud of carbon dioxide that surrounds us as we exhale. Therefore, windy days are better for hiking/fishing/camping, as the wind disperses the CO2, which makes it more difficult for the flies to detect us.
  2. Sight: Black flies rely partially on sight to find their victims, which is why they’re active during the day. However, being semi-aquatic insects, they’re more prone to dehydrating during midday when conditions are hot and dry. This is why they’re most active around sunrise/sunset, or on days when its humid and cloudy.

Not pictured: the 1000 black flies that come out just before sunset in the springtime

What to Know About Black Fly Bites

Are black fly bites harmful to humans?

In general, black fly bites are not harmful to humans in the United States.

However, there are times when swarms of black flies can be really dangerous, such as when the swarms get so thick that they have potential to block airways, or when they cause a lot of bites at once, which can cause serious adverse reactions.

You’ll normally run into huge swarms around fast moving bodies of water in black fly season, because that’s where the females lay their eggs. So if you’re venturing out to a pond, lake, waterfall, or river during springtime in the Adirondacks, its best to be ultra prepared.

However, even if you don’t get swarmed, it doesn’t mean you won’t escape your outing unscathed. Black flies tend to congregate, so you’ll often get ambushed from all angles once you venture into their territory, even if it’s just by a handful of them.

And, although one black fly bite won’t kill you, their bites are horribly unpleasant and best avoided at all costs.

Why do the bites itch for so long?

Black fly bites pack an enormous punch for something so small. Although a bite from a black fly won’t kill you, its sure to be painful and  leave a mark that’s red, swollen, and horribly itchy.
The bites are comparable to a small bee sting. They hurt so bad because the fly literally cuts a hole in your skin with its sharp little mouthparts in order to suck your blood. The itch follows shortly after, as a result of the anticoagulant in the black fly’s saliva, which makes the blood flow more freely – similar to a mosquito bite.
I’ve found that a general After Bite cream or anti-histamine typically eases the itch until the bites go away.


How to Avoid Buffalo Gnats in the Adirondacks

Basically, black flies/buffalo gnats will look for any opportunity to ruin your outdoor experience, whether you’re trying to enjoy a good book on the dock or a peaceful paddle in the Ausable River.

Avoid areas around cold fresh, running water

Black flies congregate in these areas to lay their eggs, so you’ll want to stay away from densely wooded areas near waterfalls, streams, lakes, and rivers.

Go outside midday on sunny days

Black flies in the Adirondacks are the worst just after sunrise and just before sunset because humidity is higher. They’re at serious risk of dehydration in the middle of the day when the air is warmer and drier, so this is the best time to get outside during black fly season.

Choose windy days

Windy days are quite the lifesaver, since they make it both harder for the little vampires to fly and also makes it more difficult for them to detect your CO2 clouds.

Keep car windows and doors shut when driving through black fly territory

Otherwise your vehicle will be filled with the little bastards. And, unlike other types of biting flies, black flies don’t care that they’re trapped in your vehicle. They’ll bite you anyway. This goes for your tent, too

Adirondack pond at sunset
The shores of this Adirondack pond are haven for black flies

How to Protect Yourself from Black Flies

Sometimes it’s impossible to avoid black flies altogether. In those cases, it’s best to be prepared in order to protect yourself from getting bit. Follow these tips to protect yourself from black flies, even in the worst of black fly season.

Cover all exposed skin!

Black flies in the Adirondacks will not bite through clothing. They prefer exposed areas such as the head and face, as well as areas around the wrists, ankles, and ears. So covering up any exposed areas of skin serves as good protection against a bite.
Don’t be afraid to go all out with this, there’s no fashion contest here. Tuck your shirt into your pants and your pants into your socks. And possibly opt for a pair of thin gloves. Then nod in mutual understanding toward any hikers you pass on the trail that are dressed the same exact way.

Choose light colored clothing

Dark clothing makes it easier for black flies to find you, so opt for light colored clothing, like whites, tans, and pastel colors.

Wear a bug shirt

Bug shirts are specifically designed to repel biting insects using permethrin.

Use a head net

head net for black flies

Its not uncommon to pass people on the trails wearing these head nets during black fly season. They’re not very trendy and make you look like a bee keeper, but they’re extremely effective at keeping the flies away from your face and out of your ears.

If you want something even more heavy-duty, Ben’s InvisiNet Bug Jacket and Mittens offers full upper-body protection from biting flies. It’s a fully enclosed hood with bug mittens to create a 100% bug-free area around your hands, arms, and torso.

Use a high quality black fly repellant

Sawyer Permethrin Pump Spray for black flies

Bug sprays aren’t the best defense against black flies, but they do work to keep the flies at bay. The best insect repellants for black flies contain DEET, Picardin, or essential oils such as peppermint and lavender.

A decent DEET spray is Ben’s Insect Repellent that contains 30 Percent DEET. Always use DEET products according to the directions on the back of the bottle.

I personally prefer permethrin-based spray, like Sawyer Insect Repellent. This one can be used on your clothing, gear, and tent.

For more natural bug protection, try All Terrain Herbal Armor and Natrapel Lemon Eucalyptus sprays, which contain essentials oils and are 100% DEET free. Admittedly, these don’t work as well and I wouldn’t recommend them for heavy black fly areas. However, they are chemical free, which is always a win

If you prefer to go spray-less, this article by Farmers’ Almanac lists some other natural black fly repellants (I’m not sure how well they work, though)

Avoid perfumes, sweets, and scented laundry soap

Black flies are extra attracted to perfumes and any sweet scents. There’s no faster way to sabotage your outing than to make yourself smell like a snack prior to going outdoors.

When I hike the Adirondacks in the spring, I always take extra caution to avoid eating anything sweet or washing my hair or clothes the morning of, in order to avoid becoming a fly magnet.

Environmental Control of Black Flies in the Adirondacks

So, after reading all about the horror of black fly season in the Adirondacks, you might be wondering: so what the heck are black flies good for, anyway?

Well, it may (or may not) come as a surprise to know that although black flies are a nightmare for us humans, they’re actually a super important part of the ecosystem. Black fly larvae are a vital part of the food chain around rivers and streams. And since the adults breed in fresh, clean water, scientists use black flies as indicators of a healthy ecosystem.

So, as terrible as they are for us, I guess they are good for those things. That’s basically it, though.

The annual battle with the Adirondack black flies has become more important as tourism in the Adirondacks continues to grow. I mean, who wants to see springtime in the ADK damned by swarms of flies?

In efforts lead by the New York State Department of Environmental Conservation, waterways around towns and tourist hotspots are treated with a non-toxic bacteria, to try and combat these obnoxious insects.

Bacillus thuringensis israelensis, or ‘Bti’ for short, is a naturally occurring bacteria that contains acidic proteins that essentially dissolve the insides of the black flies when they ingest them. The water treatment usually begins around early April and occurs several times throughout black fly season.

Apparently this method of black fly control is pretty effective, because towns in the Adirondacks spend tons of money on it every year.

Now if only they would apply the same type of control for the deer flies….

Visiting the Adirondacks? Here are some posts you might enjoy:

17 Cozy Cabins to Rent in the Adirondacks

Indian Head and Fish Hawk Cliffs Hiking Guide

Short Hikes with the Best Views in the Adirondacks


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