This is an easy project to make when you've got a fruit fly infestation. One little bug in your house? "Oh well," you said. But if you ignore them, you'll have a whole army of them before you know it. Before that happens, or once it happens, make this trap to put an end to them.
There are some pluses to this project:
1) You won't have to feel bad about killing them because really, you're not. You can release them outside later on if you wish.
2) Its inexpensive.

3) Its easy to make.

4) Even my six year old sister can make it, so age is not a factor here :)

*I DO NOT OWN THE IMAGES SEEN IN THIS PROJECT*

When I have the time, I'll take them out and use pictures of my own. Until then, hope you enjoy the Instructable

Step 1: Materials

All you'll need is:
a cup,
some plastic wrap,
a fork,
bait (a couple of pieces of fruit, perhaps the ones the flies tend to enjoy)
an elastic band,
and your hands.

Step 2: Setting the Bait...

1) Put your bait into the cup. The bait can be a couple pieces of fruits, or even fruit scraps and leftovers. (Really, only two or three pieces are needed, unlike in picture, which has plenty)

Step 3: Assembling the Trap... the Lid

2) Cut a piece of plastic wrap that will easily cover the mouth of your cup using the cutting tool attached to the box of the plastic wrap. It is more than okay for your piece of plastic wrap to be bigger than necessary to cover the cup's mouth.

Step 4: Securing the Lid...

3) Put the piece of plastic wrap on top of the cup's mouth. Smooth the edges down, then tie the elastic band on it.

Step 5: Perfecting the Lid...

4) Pull the edges of the plastic wrap below the elastic band to make the closed surface smooth.

Step 6: Finding a Way In...

5) Lastly, use the fork to poke MANY holes in the plastic wrap.

Step 7: Place the Trap!

Now place the trap into an infested area. Now the fruit flies can crawl in the trap, but they get stuck there and can't escape. For some reason, it is easy for them to get in but hard to get out.

Step 8: Releasing...

Once you've collected some flies, its time to get rid of them.
What my siblings did once was pick up the cup and shake the fruit around and squish them all... that would require some gross cleaning later on.
For a less messy escape, go outside and open the lid. Allow them to fly away, then reclaim your belongings.
I think you could also flood the trap by filling it with water then drowning them. Then you could open the lid and pour the "mixture" out.

Step 9: Tips...

*It helps if you remove any other fruit around the area/house because they might just go after that instead of going into the trap.

*If they are escaping easily, your holes might be too big.

Thanks for reading!
Hope this helps with your infestation!
Please leave comments below!