I can not tolerate fruit flies in my house. One year, I decided to buy one of those cute banana stands that shows off your bananas. Bad, bad mistake. Fruit flies took over my house. I just about went nuts getting rid of them until I found this idea. I have been using it ever since.
Yesterday, I made my Hubs banana bread. While it was cooling, I seen about 4 fruit flies trying to get at it. I covered the banana bread with a glass container and then set out getting rid of the flies.
All you need is an oven with a light, and food that attracts fruit flies.
Here, I used wine, kefir milk and a lemon. I put all of those on a piece of tin foil in my oven, turned the light on, left the oven door open for them and then went to take my bath. When I came out, there were about 7 fruit flies in my oven on the food. I closed the oven door and turned the oven on for a few minutes. All the fruit flies died of heat exaustion.
I got rid of the dead fruit flies, put a clean piece of tin foil down and put in some fresh food. I again left the oven door open with the light on to attract them. When I got up there were only 2 fruit flies around the food...... I killed them too.
For me, this is fool proof. I might not have to do this again this year, but if I do.... I am ready.