I belong to a local Bird Club, this months news letter gave a fruit fly tip that I will share.Just leave left overs from your bird's veggie dish or a banana peel into a plastic bag.Leave the bag open over night on the counter.The flies will go into the bag to feed during the night-in the morning carefully close the bag and toss the flies in the trash. Do this a couple nights to clear up the problem.
So if I ever get that problem I will try it.