The "paper cone of death" fruit fly trap is one way to kill those annoying little pests. But, the other day, when I was having trouble fitting a paper cone into my glass, I discovered an alternate solution that's just as effective!
The basic principle is the same: wine, fruit juice or apple cider vinegar lures in the flies. A few dots of dishwashing liquid on top helps prevent their escape and, just to be sure, the cone or, in this case, a piece of clear plastic wrap dotted with three or four fruit fly-sized holes, is a physical barrier to their exit. As they used to say about a certain kind of roach trap, fruit flies check in but they don't check out.
I used Glad Press and Seal, but you can use any kind of plastic wrap. A rubber band or hair elastic can be used to ensure a tight seal. Don't make your holes too big; a toothpick makes one that is just the right size.
(Image: Abigail Stone)
Dirty Little Secrets of Tidy Families
Hillary & Michael's Refined Roost
Good Food to Share 
The Big Book of Small, Cool Spaces 
Apartment Therapy Presents 
The Eight-Step Home Cure 
Nomade Express Slee...
How To Cook Fluffy, Tasty Quinoa
My Staple Summer Cocktail Recipe: Campari & IPA Spritzer
Thank you so much for this post! I had a fruit fly infestation and got really sick of waiting for them to die off and be vacuumed from my window sills. If it happens again, I'm doing the death trap!
A bowl of water works just as well.
dish soap alone works just as well too... just pour some on a plate, the fruit flies fly into it and get stuck, then dissolve. Easiest/laziest solution!
Actually I think the easiest solution is mine... open bottle of red wine, drink, leave a small amount at the bottom. They are attracted to the wine and can fly in but have a heck of a time getting out. Works better than any traps I have rigged up.
I just used the trap last week and it worked great. I used the smallest funnel from my set and a tall bottle with a bit of balsamic vinegar and dish soap. The funnel was less likely to fall off and fit more tightly in the jar top than the paper cone. I don't use plastic wrap for anything so it's not something I have lying around.
I 2nd the commenter above who said no barrier is needed. I just tried this a couple days ago following an older post on this site that recommended setting out a mixture of cider vinegar and dish soap, and it works great. Even with my hippie-dippie eco-friendly rosemary-scented dish soap.
This traps some of them, but it really doesn't get rid of them. The key is to remove anything for them to eat for a few days while keeping the kitchen pristine. Keep everything in closed containers or the fridge (no bananas or apples sitting out, no dishes in the sink, keep compost fully contained, keep food scraps out of your drain filter). Put out one of these traps and wait for all of them to die before resuming your normal kitchen habits.
The trap on it's own will do little to help an fruit fly infestation without taking other measures!
My old roommates would never believe me that this worked. I would set out a glass with wine and dish soap, and they would put paper cones in it. Now that I live in my own place, I've never used a barrier and it has never failed me. It may take a little longer, but it is worth it to not have to look at a gross jar full of fruit flies slowly approaching death.
I go with the red wine in a bottle method as well. One tip though- make sure you wipe clean the lip of the bottle. That way the flies make it all the way in and don't get distracted by the residue at the opening.
Cool! This is the same principle as the VIP (ventilated improved pit, as in latrine), in which a ventilating pipe comes out of the latrine pit, with a mesh on top. Flies flock to the poop in the latrine (whose main hole is covered when not in use), then fly up toward the light in the ventilation pipe to get out, except they can't. Big improvement in hygiene in developing countries.
You definitely need the cling wrap! I had a friend who had a horrible infestation and used just the vinegar and dish soap method in a long-necked container, minus the plastic wrap, and the fruit flies were breeding like, well, fruit flies. Once the plastic wrap was secure, the fruit flies died out.
Very informative thanks
Does anyone know if the fruit flies attack your house plants ? If they do how can I get rid of them.