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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.

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