When I first moved to Maine, I had a few people warn me about black flies. Being from the west, I had never heard of black flies. “Aren’t all flies black?” I asked.

Boy, was I in for a treat!

When we moved to rural Maine to start our little backyard homestead, I got my first taste of serious black fly season, and it is serious. Worst of all, black fly season comes right at the time when we have to plant our large vegetable garden for the year, which means we are getting exposed to those little meanies all day long for many, many days, sometimes a couple of weeks.

No, worst of all is my husband’s reaction to the black flies. For me, as miserable as they are, the black fly bites aren’t that bad. Right now, I’m covered in tiny red circles, but they don’t itch much and are not swollen. This is not the case for my husband. He swells, itches, and has a pretty severe allergic reaction to black flies.

For people who are allergic to black fly bites, the bites can swell to nearly the size of a golf ball, and this happens regularly to my poor husband. Multiply a golf ball times about 40 or 50, and you can imagine my poor husband during the worst of black fly season. It’s a worry.

My husband says he wouldn’t mind sharing his blood with the female black flies who need the blood for ovulation. After all, many people have pointed out that black flies are good for the environment. They feed the baby birds who hatch in the spring, and I’ve read it’s actually a good sign that we are cleaning up water in our state when the black flies are bad. However, he says he wishes those ladies wouldn’t leave such a mark.

So black flies are good for the environment, but what if they aren’t good for you? What can we do to treat and prevent bites, and what should you know about severe allergic reactions?

Symptoms of Allergic Reactions

Although black flies in our area do not carry the dangerous diseases that black flies in other parts of the world carry, reactions to them can still be painful and serious. People with strong allergic reactions may experience the following symptoms:

  • Extreme swelling
  • Large, painful lumps at the site of the bite
  • Severe itching
  • Black fly fever, which includes headache, nausea, fever, and swollen lymph nodes in the neck

If someone you know has a severe reaction and gets really sick, it’s important to contact your doctor and seek medical help. Additionally, if the bite wounds do not heal, become painful, or produce yellow drainage, you should see your doctor. The bites can become infected.

Although I could find no research on black flies in our part of the world causing death in humans, they can cause death in animals who have no way of preventing the many bites.


Treatment for black fly bites can be a little difficult for people who are highly allergic.

If you’re not highly allergic, any kind of anti-itch cream helps out. If you’re highly allergic, you should still try the anti-itch cream. It will help—some.  To help with the swelling, apply a cold pack to the bite area. You can also try a cool bath with Epsom salt if you have a lot of bites on you.

My poor husband has tried everything from hydrocortisone to tea bags and usually just suffers for a few weeks with a lumpy body. Hopefully, this will not be the case for you or someone you love. It’s hard to watch someone suffer from these bites.


With all this in mind, prevention is the best option, though there is not much we can do to actually control the flies themselves. We simply have to take steps to defend ourselves from the flies.

  • Avoid too much outside time during peak season, if you can. This is not an option for me and my husband because of planting season, but we try.
  • If you have to work in your garden or go for that hike, which is definitely sometimes necessary, try to venture out on sunny or windy days. Black flies are less present in bright sunshine, and the wind helps keep them at bay as well.
  • Wear clothing that covers as much of your skin as possible. They can bite through thin clothing, but clothing does help.
  • Especially if you are allergic, use some repellent. We have had good luck with picaridin, and after much research, we can’t find any evidence that picaridin has any negative long-term effects.

We’ve tried natural preventatives without much luck. Last year, I read to add pure vanilla extract to some water and spay it all over yourself. I did that. I sprayed my husband as well. It didn’t work, but we smelled really nice!

So what’s your advice for prevention and treatment? We’ve been at this black fly thing for only about six years, so I’d love to hear from an old pro.

In the meantime, for my husband’s take on the whole black fly “adventure,” please check out his guest post, “The black fly attack: A humorous take on a bad situation” here. I promise you will laugh out loud—and also probably empathize with the misery.

And for more research on dealing with black flies, check out this helpful site from Purdue.

Crystal Sands

I am a former academic and award winning writing teacher turned hobby farmer/homeschooling mom/freelancer. In 2015, after too many years of working too many hours, I decided to change my life. This...