We go through a lot of bananas in our family. My wife uses them in smoothies, my son eats them as snacks, and I take them along on bike rides and walks. Occasionally, however, a bunch of bananas will turn before we can finish them and within hours, it seems, our kitchen is filled with fruit flies. Soon, they have spread to the rest of our apartment: alighting on the tip of my nose while I try to watch TV or, worse, attracted to my book light as I read before bed.
Fortunately, getting rid of these flying pests is not very difficult. A commonly suggested method is to pour a little bit of apple cider vinegar in a cup and add a teaspoon of dish washing liquid. (The vinegar attracts the flies, while the soap apparently retards surface tension and causes the flies to sink rather than float on the vinegar.) To complete the DIY trap, top it off with a bit of cling wrap as shown in this post from Sew Tara. Stretch the film across the top of the container, using an elastic band to hold it tight. Poke three or four small holes in the top and any fruit flies that find the liquid but don’t drown will still be trapped under the cling wrap.
If vinegar isn’t working, try red wine, or, as a user at Chow.com suggests, cooked potato peelings as bait.