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help identifying gnat-like insect #292593

Asked December 04, 2015, 1:19 PM EST

i have these gnat like looking bugs in my house. primarily located in my basement, but some upstairs (2 level home). i've put fly traps in my garage and basement and have caught many. i do have small gaps in my door leading from garage to basement which could be the source of infiltration. or maybe they live inside, i don't know. i moved into the home almost 1 year ago and they have always been around to some extent, but seem to have more of them at some times of the year versus other (not sure any correlation here). i don't think they are living in any drains as i keep the traps full of water and have taped over drains to see if I could catch any and I couldn't. they don't bite. the pictures aren't great (sorry I have bad photographer skills) but they have dark eyes (not red). they are attracted to light (like most bugs i suppose) as i always find them on the TV in a dark room. they are slow enough that i can catch them with 1 hand to squeeze and kill. i don't have any flowers/plants or pets inside the house. although its quite possible the old owners of the house could've had any combination of flowers/plants/pets. what is it and how do i get rid of them? i suppose if i could at least figure out where they come from (outside the house or inside) that would be a start. any help would be appreciated!!

Montgomery County Maryland

Expert Response

The insects in your photos look like a type of sewage fly.  These flies are commonly associated with moist decaying matter. They like the gelatinous lining in drains and the larvae feed on this. Check your sump pump and all drains.  Some other sources include compost piles outdoors (make sure it is not wet) or buckets indoors especially if you are adding kitchen refuse.  You need to find a breeding site or sites.  Make sure you have no leaks.  If you find the issue are drains, clean the traps and drains mechanically or  an over the counter drain cleaner with enzymes followed by hot water.                                                                  
mh
i was able to get some high resolution photos and it seems like i have more than 1 type of fly! i've attached the photos and was hoping you could help me identify them so i can start figuring out what to do with each one. thank you!!!
The Question Asker Replied December 15, 2015, 10:45 AM EST
 There are many species of flies, but control options are basically all the same, in that they all need wet areas to multiply, so do the above to clean up and dry out.
Be sure to check sump pumps and under sink areas or any leaking water pipes. Do not use any sprays or pesticides indoors.
Our entomologist said one is a fungus gnat, and those usually rise from houseplants which are kept too damp or are holding water under their containers in saucers. Dump those, and allow the potting soil to dry out to kill the larvae.

cm

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