1. Put a 3 tbs or more balsamic vinegar in a shallow bowl or glass
2. Fill remainder with water up to the rim
3. Put some dish soap on your finger and gently touch the surface of the water to break the surface tension.
4. Leave it out for 24 hours or more.
In 24 hours, this method caught 30 fruit flies at my house and turned my kitchen from a thriving fruit fly metropolis into a veritable fruit fly ghost town. Probably the highlight of my week.
Anyone else have good methods? Feel free to share!
(I was just kidding about it being my week's highlight.)
I tried a new glass of this Saturday and you really have to work hard to get the surface tension correct. The last 3 flies I saw kept sitting on the edge drinking the liquid and not falling in. Just keep touching the surface with soap, fill it as full as you can or try adding some leftover wine. I finally got it working again, but was super frustrated for a while.