Triad -- Fruit flies seem to appear a lot about this time of year. They are attracted to rotting fruit and vegetables. It doesn't necessarily mean you have a dirty house. It means that you may have one rotten banana or some spilled juice under the fridge or even the garbage disposal could be the trouble maker.
Here's how it works. Fruit flies can be brought in from the garden or even from the grocery store. They lay their eggs on rotting organic matter. If you have anything with a rotten spot, they flies could settle in and begin to thrive.
They can also breed in drains, garbage disposals, trash cans, recycle bins and even mops and cleaning rags. Make sure you clean them often.
Finding the source of the problem is the first priority. It may be that you have one rotting potato way in the back of the pantry. It may take some digging but until the source is eliminated, they problem won't go away.
If you think the fruit flies are breeding in the drain, tape a plastic bag over the opening one night. If there are flies in it the next day, you've found the source!
Once you locate where they're coming from, it's time to get rid of them. Here's an easy fix. Get a jar and put either some cider vinegar or a banana in the bottom. Then make a cone out of a piece of paper and put that over the top. The flies will go for the smell but won't be able to get out. Turns out, they're more annoying than they are intelligent!
University of Kentucky Entomology