Have an issue with fruit flies or gnats? The first thing you should do is try to identify the source. Do you have overflowing trash that should have been taken out days ago? Rotting fruit? A garbage disposal in your kitchen sink that is in desperate need of a cleaning? If possible, the source should always be identified, in order to prevent any future reinfestations.
After identifying the source, the next step is to remove the flies. For this part you will need a small bowl, some apple cider vinegar, clear saran wrap, and a fork. Pour a small amount of apple cider vinegar into the bowl…maybe half an inch or so. Next, tightly cover the bowl with the clear saran wrap. After covering the bowl, use the fork to poke about 20 to 25 holes in the top of it. Place the bowl in the area that seems to have the most concentrated amounts of flies. Fruit flies and gnats are attracted to apple cider vinegar. They will find their way to the bowl, fly in through the holes, but will be unable to get out, eventually getting exhausted and drowning in the liquid. Have various problem areas? Make multiple bowls, placing one into each affected area.
I recently had an issue with fruit flies in my home. I placed one bowl in the kitchen, as well as one in the guest bathroom, the two main affected areas. Within about two days, I had caught about 75 fruit flies between the 2 bowls. Good luck!