I also have a gnat problem again this year. The only thing that worked for me was to take a 9 oz. or larger glass, make a funnel out of paper (computer or notebook) with a tiny opening at bottom. Make the top (opening for gnat entrance) large enough to fit in the glass and use tape to hold it in place. I found they will find a way out if the bottom funnel hole is too large and or if the top part isn't taped securely around the glass.
Pour enough apple cider vinegar in glass (before adding funnel), to get it as close as possible to bottom of funnel. The smell of vinegar attracts them to the funnel and in they go and can't get out. You'll see them walking around inside the glass trying every way possible to get out. They'll get tired and drown in the apple cider vinegar. Place these where you see them the most, in the kitchen, bathroom, laundry room, etc. They like moist areas. Remember to redo every couple days. I tried plastic cups, but for some reason, they go to the glass better. Good luck!
By adbdnc from NH
This page contains the following solutions.
Recently our house has been overrun with gnats. I followed all your suggestions, nothing worked. I finally called an exterminator, he couldn't come but he told us to pour scalding water down every drain in our house and follow it up with bleach.
Gnats and fruit flies love sweet liquids. You don't have to use wine, although they do like it. Add a few drops of dishwashing liquid (only about 3) to wine and slowly stir this makes a film on the surface that the bugs get trapped in.
Everyone knows how annoying gnats can be. Once they are there, it's very hard to get rid of. They nest in damp places, such as sink drains.
