Fruit flies are harmless but incredibly annoying, and unless you take action they will colonize your kitchen and sip your wine as you try to drink it. The web (including instructables) is full of solutions, most following the simple principle of a trap with liquid bait in which the flies will drown. My solution is no different. These traps all work, but frankly, they're all eyesores.
This is why I designed this simple template. I fiddled with the size and shape of the cut and fold lines, then worked some photoshop magic on shots of an orange. You can get this orange template from my website, or use this free blank template I uploaded here and decorate it yourself.
Step 1: Five minutes of time
All you need is about five minutes plus some regular paper, scissors, glue (or tape) a jar and some vinegar, wine, beer or juice and you'll be looking good in the extermination business!
You'll also need the templates, obviously. You can download this trompe l'oeil orange from my website (for $1) or use the free blank PDF file I uploaded to step one instructables and decorate it yourself. You can also get the blank template and all my other free designs here in case you can't download the PDF from Instructables.
The orange template is designed to be printed on both sides of a single sheet of paper, so that the cut and fold lines will be invisible on the final product.
Please note: if you're upset that I'm charging a dollars for the orange template, because everything should be free on instructables, there IS a work-around. I've been trying to get people to post pictures of their work done with my templates, because I love seeing how people use my designs and make them personal, and I think it's inspiring for others too -- so if you make this blank template (or any other of my templates), decorate it, photograph it and post it here, I'll email you a dollar coupon and you can get my orange design orange for free...Deal?
Step 2: Make the cone
Print my template on a color printer double sided (you can easily feed the same sheet of paper into your printer twice if you don't have the duplexing option).
Cut out the template on the black lines, then score your fold line by drawing firmly along the dotted line with a ball point pen (hint: a soft felt tip won't help...).
Fold the cone by pinching the template along your scored line.
Glue the tabs and you're done!
Step 3: Prepare the trap
The past times I've had infestations I've used wine and beer as bait, because that's what seems to attract my fruit flies (and it worked very well), but if you don't want to share your favorite beverages with these nasty creatures, apparently vinegar works well too.
Put about an inch of your chosen liquid into a jar or cup (with a diameter of about 2.5"). Add a drop of liquid soap if you'd like to speed up drowning (this will reduce the surface tension of the water so they will sink when they hit the water rather than skate), but don't put more than a drop or the soapy smell might interfere with the bait scent.
Top it off with your paper cone, and place it near your infestation. They will fall like flies.....