RSS Feed
Email this article
Printer friendly page

Ask Rick A Question

Black Flies


Summary: I cannot think of many things worse than fighting off biting black flies while outside trying to enjoy my time off. They seem to get in all the places where their painful bites are the worst like shoe tops, under belts and collars and up noses.

Yee-ouch! I just felt like I got stuck with a blunt needle. Precisely the reaction one gets when encountering the tiny, but powerful black fly. At least that is the case with certain species of this insufferable insect. Other species of black flies just flit about your ears, nostrils and other exposed skin making your life miserable while you are trying to get in some good recreational hours fishing, camping or playing golf. Did you know it is impossible to make a fifteen foot putt with a black fly up your nose?


Not only does the black fly bite, it leaves behind a bleeding red, swollen spot that itches like crazy for several days. Their mouthparts are similar to a horse fly's blade-like appendage. Plus, they bite you in areas not easily scratched. Places where your clothing fits tightest around your body like above or below a belt, boot tops or just under the rim of your hat. Black flies usually bite during the day, preferring outdoor shaded areas. They do not bite while indoors or late at night. So, if you are fighting something while watching the late news, it is not a black fly.

More bad news. Black flies are great fliers being able to travel nearly ten miles from their breeding sites, or further if they pick up a good wind current. Just because you don't live near a body of water does not mean you are safe from black flies.  Black flies are attracted to mammals by the carbon dioxide and moisture in exhaled breath, dark colors, convection currents, perspiration, perfumes, toiletries, etc.

The darned thing about black fly populations is that the cleaner we make our streams and lakes, the better it goes for black fly population. Being aquatic insects, black flies don't do well in polluted water. So, after all that work cleaning up our water we get black flies as a “Thank you.” Doesn't seem fair!
Black flies, as a rule, measure about 1/8-inch and range in color from black to gray to sort of a yellowish tint. Females scatter 150 to 500 little cream-colored eggs on the surface of the water or they attach little masses of eggs to vegetation or stones nearby a running water source like a stream or river. When the eggs hatch in about five days, the larvae grab on to submerged object where they can appear to be moss-like. Their entire life

Black fly larvae

span is from four to six weeks, depending up variables like species, available food and temperature, but they can product up to seven generations per year.

Hold on, partner! Before you rush out to help the profits of the pesticide manufacturing industry I need to tell you there is little you, the homeowner, can do to control the black fly population. I can tell you how to avoid them, but not control them. To stay free of their attacks you can put away your golf clubs during the black fly season which occurs, of course, just as you are getting your swing back in shape. Insect repellents do a decent job depending upon which black fly species you are defending against. Unfortunately, there are some species that don't give a hoot about DEET insect repellent, even if you lather it on. If you are trying to enjoy an evening on the porch you might want to hold your cold drink in one hand and your can of fly spray in the other.

Our local governments promise the best control by knocking out the black fly breeding spots. Something simple like building temporary dams can reduce populations and removing vegetation over-growth in streams. Aerial fogging with a pesticide also works to provide temporary relief, although these treatments are often looked upon as being politically incorrect.

Pennsylvania has a Black Fly Suppression Program operated by the Pennsylvania Department of Environmental Research that uses Bti, the

Black fly bites

bacterium, Bacillus thuringiensis Berliner var. israelensis.  It is applied via aircraft over waters known to contain the black fly larvae. This nontoxic treatment has also been used in New Hampshire since around 1998 and has successfully knocked back the black fly regeneration at certain test golf courses.

Black fly populations are found in many parts of North America and because they are so widespread their total eradication is unlikely. As I said, they are great fliers and they don't stick around waiting for us to kill them off with pesticides. So, your choice is to hide inside or man your battle stations with repellents, garments that don't attract them (dark blue) and insect sprays to keep them at bay, and go out and live life.

Ask Rick A Question


21 Apr 2012, 16:39
Mid MI April, we've had spring weather in March and the black flies are here. It used to be that they were only in the upper penninsula but last year we had them. I thought the black flies were just nats, wrong. I've had a stoke so my right side is in-sensitive and I was covered in bites all around my shoulders, neck, ears and some on arms and legs. I only felt a couple you know the rest of the story, looking for some relief. Thanks for the advise.
Adrienne Downs
16 May 2012, 18:54
I believe I was bitten by black fly or flies as looks more than one bite. It has a dark red/purple colour surrounding one small bite with what looks like a hole in the middle and white blister looking spots nearby, which is hard and hottish with a painful itch. Have had it for 4 days with no relief. Should I go to a Doctor? I find polysporin relieves the itching for a while. Thanks.
sharon jensen
27 May 2012, 11:45
Good morning Exterminator. Within the past 5 days I have been infested with tiny black biting flies. Not so much outside, but in my kitchen and living room area. Oh what to do. Can you recommend some kind of home remedy? I have vaccuumed my floors and furniture but to no avail, they suddenly re-appear. Please help. Sincerely, Sharon Jensen, Santa Rosa, Ca.
27 May 2012, 11:47
I worked in forestry here in NW B.C. before I retired. I found the best protection for my neck and ears to be a lightly-sprayed (Deet - whatever) bandana tucked under the back of a hat "foreign legion" style. Almost fool-proof! Ironic, though, that I wound up at this site searching for any new remedy for the incessant itching from the bite on my arm. Man! they're out early this year!
02 Jun 2012, 02:08
Have lived in the Spokane, Washington, area for 12 years. Fall 2011 was the first time I'd ever experienced anything like this. Was in my yard in the evening. Felt something on the top of my head. When I touched it, there was blood on my fingers. It turned into a large itchy lump. Then last night I was out mowing my lawn. I was only out there for maybe 15 minutes. It was near dusk. Got nailed 3 times on my scalp. How do they even get through my hair? (Although it was windy.) Never see them nor hear them. It is awful! Can't even enjoy the beautiful evening. Last year I bought a hat with a net on it from REI because I can't put repellent all over my hair. But I didn't have it on last night. I didn't know they were BACK! I have gotten itch relief from using SssstingStop. I'm not sure if it is still on the market or not. Phone # on the box is 800-876-9505.
17 Jun 2012, 23:19
I went to the lake yesterday and I now have FIFTEEN welts on my head , and they are super itchy. Behind my ears and neck and face and hair. It's sickening.
25 Jul 2012, 16:57
Louisburg national park, Cape Breton, Nova Scotia. Just returned from a hike down to the Ocean Cliffs with the dogs, passing two areas with board walk and heavy vegetation hiding still water. When we got back to the truck we thought to check for ticks. Instead we found tiny black flies on the dogs bellies with red spots. My dad and husband each had a bite. My one dog has one bite with the swelling red ring whitish puffy centre. They don't seem to be bothering the dogs..yet...
14 May 2013, 11:50
One thing that seems to work on cutting down the numbers of black flies is my skeeter vac. I knew they would be coming out so I got it up and running, first couple days were bad, but then the skeeter vac started killing enough off to make a noticeable difference. The catch container has "best guess" 1000 or more of the litter blood suckers in it after 2 weeks of running. If you are in an area prone to them, get a skeeter vac and it will help.
13 Jul 2013, 13:58
Question, a few years ago a fly stung inside of my nose on the bottom, and I had a recurring opening wound of some kind that kept coming back for about a year or a little more! Anyone know if this might have been a black fly, or what the wound might have been?
13 May 2014, 09:43
if the spring is cold ..does that mean the black flies will be here longer?
Notify me about new comments on this page
Hide my email
The box below is for visitor comments! Questions posted in this box may not be answered by Ask the Exterminator. For quickest response click on the "Ask the Exterminator a Question" link at top of this page.
Security Image:



More Articles Like This

  • Pipevine Swallowtail Caterpillar
  • Robber Fly
  • Get Rid of Gnats
  • Fly Control
  • Blowfly
  • Sand Flies
  • Horse Fly
  • House Flies
  • Garbage Maggots

  • Categories: