Home & Garden Home Humane, Homemade Fruit Fly Trap By Doris Lin Writer University of Southern California MIT Doris Lin an animal rights attorney and the Director of Legal and Government Affairs for the Animal Protection League of New Jersey. our editorial process Doris Lin Updated July 01, 2018 Aukid Phumsirichat / EyeEm / Getty Images Share Twitter Pinterest Email Home Pest Control Natural Cleaning DIY Family Green Living Thrift & Minimalism Sustainable Eating A fruit fly infestation can be a huge nuisance and quite difficult to eliminate. This homemade trap is easy to make, effective, and uses no harsh insecticides. Read through the instructions once and look at the photos before making this trap. 1 of 6 Start with a piece of paper Doris Lin To make a humane, homemade fruit fly trap, you will need: Piece of paper Jar or cup with a small opening Tape Piece of fruit for bait Start by rolling the piece of paper into a cone. To form a cone, start pulling two adjacent corners of the paper towards each other, along the long side of a sheet of paper. 2 of 6 Curl the Paper Into a Cone Doris Lin Using both hands, Continue bringing the corners of the page together, and overlap them, curling the paper into a cone shape. 3 of 6 Finish the Paper Cone Doris Lin Read through the instructions once and look at the photos before making this trap, so that you can see how big the cone needs to be, in relation to the jar or cup. Curl the paper into a tight cone, with an opening in the tip of about 2-3 mm (less than one-eighth of an inch). You want a fairly wide cone, so don't curl it too tightly. Secure with tape near the point. If you forgot to leave an opening in the tip of your cone, you could snip off the tip, but it's better to remove the tape and adjust the cone, becuase it's too easy to snip off too much. Cut off the wide end of the cone, so that the cone is about 4-6 inches (10-15 cm) tall. 4 of 6 Set the Bait Doris Lin Set aside the paper cone. Now, place a small piece of fruit (I've found that bananas and peaches work well) in the bottom of the jar or cup. I've used a piece of banana peel and a baby food jar in this photo. 5 of 6 Attach the Paper Cone to the Jar Doris Lin Set the paper cone into the top of the jar. The top of the paper cone should easily rise above the top of the jar, and the point of the cone should stop before it reaches the fruit or the bottom of the jar. Secure the cone to the jar with two pieces of tape. You want to make sure that tape holds the cone snugly in the jar, without putting so much pressure on the cone that it buckles. Your trap is done! Before setting it out, make sure there are no other fruit fly attractants in the room. Take out the garbage, empty your compost bucket, wash the dishes and hide your basket of fruit in the fridge or someplace where fruit flies will not smell your fruit. Set the trap on a countertop, next to a garbage can, or wherever you have seen fruit flies. Within minutes, you will probably have a fly or two landing on top of the paper cone. Walk away, and check the trap in a couple of hours. 6 of 6 Release the Fruit Flies Doris Lin Fruit flies will follow the scent of the fruit down into the opening at the bottom of the cone, but once inside, they cannot find their way back out. After a couple of hours, you will probably find some fruit flies in your trap. This is where the humane part comes in: Take your trap outside, remove the tape and remove the paper cone to release the fruit flies. Don't let your trap go unchecked for longer than overnight. You don't want to keep them trapped for too long, and if they stay in there for more than a day, the eggs will start to hatch. Chances are, you didn't catch all of the flies in the first couple of hours, so you'll have to re-set the trap. To re-set the trap, remove the bait, replace it with a new piece of fruit, then tape the paper cone back into place. If you continue to use the same piece of bait, the eggs on it will hatch and you will end up breeding fruit flies inside your trap. Troubleshooting: If flies are not attracted to your trap, make sure there are no other attractants (food, garbage, dirty dishes, etc.) in the area. You can also try using a different kind of fruit as bait. If fruit flies are moving freely into and out of your trap, the hole in the bottom of the cone might be too large. Release any flies who are in your trap, then make the paper cone with a smaller hole in the tip. You want the hole to be barely larger than a fruit fly. Another problem may be that the paper cone is wrinkled and doesn't fit snugly into the opening of the jar, all the way around. Make a new cone, and be careful not to wrinkle the paper. Doris Lin, Esq. is an animal rights attorney and Director of Legal Affairs for the Animal Protection League of NJ.