Flying in circles under my deck - Ask Extension
Every spring and summer I have a swarm of flying bugs that fly around in a kind of hovering pattern (circular motions in a radius of about 3' - 5'). T...
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Flying in circles under my deck #758204
Asked June 24, 2021, 3:39 PM EDT
Every spring and summer I have a swarm of flying bugs that fly around in a kind of hovering pattern (circular motions in a radius of about 3' - 5'). They aren't like regular flies that will go all over the place. They stay under the deck and occasionally travel a bit further. I've tried everything - sprays, zappers, fly strips, etc.; but no matter how many meet their death on a fly strip, there are always about 30 at any given time. They don't like the cold weather and I don't think they like it when it is very hot. They also bite! Can you help identify what they are and how I can get rid of them? Are they there because of the wood deck? I have a big (long) backyard for DC standards, and they are not any where else in the yard - just under the deck. For reference the fly strip is about 1.5" wide.
District of Columbia County District of Columbia
Expert Response
There is no association between decks and flies.
Flies are attracted to moist decomposing organic matter, such as garbage, pet waste or something similar: https://extension.umd.edu/resource/flies-indoors
You don't mention what is under the deck. Consider what may be falling through the decking from above, such as bird seed, pet food or human food.
Eliminate any organic matter where they may be feeding or breeding.
Dry up the area under the deck.
Ellen
