I saw where someone ask about fruit flies in a fruit storage post. Here are some traps I made this past summer that are crazy effective. After placing these traps in our kitchen and bathroom(they bred in our bathroom sink) All fruit flies were gone in 48 hours.
What makes these so effective is the mesh funnel. It allows the smell of the bait, in this case apple cider vinegar diluted 50%, to easily loft into the room. The mesh also encourages them to travel down inside the jar. The vinegar pickles the flies so there is no dead smell. They are easy to clean also.
We leave fruit and veggies out on our counter and the fruit flies prefer the traps to the real thing.
You will need a 1 gallon paper/mesh paint strainer (from the paint store) , wide mouth mason jar with ring, a hot glue gun, and very sharp knife/razor blade and scissors.
Set the strainer in the ring. While holding it snugly, hot glue it to the ring from the bottom and allow to cool. Using the knife or razor, cut the strainer flush with the top of the ring. Snip the tip of the strainer making it into a funnel. Place a cup or so of diluted apple cider vinegar into the jar and screw the lid/ funnel on.
The smell Will draw them to it so it can be placed out of sight of you wish. I left it next to the fruit till the were under control.