You will probably need to discard the fruit you have on hand first.
We had luck with a sticky fly strip (they are for flys, come in a thing that looks like a spool of thread kind of, you can find it at Walmart in the pest control area. You hang it, pull the strip so that it unwinds, and we put a glass or bowl of wine under it. Bring in new fruit, and keep it in the fridge for a week or so, untill you get rid of them. They lay eggs and re hatch and die really quickly, so once you get rid of the thing they like the most, they will even land on wet sponges, etc, so you may need to just put everything away that they are attracted too until you catch them on the strip. Apple cider vinegar in a large bowl helps too, and they drown in it if they land sometimes, but we have had the most luck with the sticky strip.
Also, run hot water in your disposal and run it for a while and make sure that there is nothing left in there for them to eat.
I hate those things, but I like to keep fruit out for my kids all the time. It can be such a pain! Oh, and we brought them home in the onions last time, so check your pantry for the oninons and the potatos too!
M.
Riley, you crack me up. My mother tells people "what in the world would you want with flys anyway?" when they say "you attract more flies with honey..." Then she says, if you really want flys, carry a sack of garbage! If you want to attract nice people instead of flys, don't seem like you are carrying around a nasty sack of trash!"
Try the sticky thing, it works, and your son will love looking at all the flys you catch! It is a cool science experiement.