There are so many piles of summer-ripe produce in your kitchen. And that means fruit flies will float up in unexpected, annoying clouds whenever you reach for a tomato or a peach. Read on to learn how to make DIY fruit fly traps effectively.
My past efforts at trapping and killing fruit flies have been half-hearted, as I didn’t really know which method worked best. So I decided to run a semi-scientific test. Out of the homemade, DIY fruit fly trap methods, which was best? I set up four different tests, and to my surprise, one method stood out very clearly as the winner.
Full warning: In the spirit of really nailing this down and showing my work, I’m gonna show you some drowned fruit flies.
The Methods
I used four classic DIY methods to trap (and kill!) fruit flies. Three involve Mason jars, and one is the really low-lift method of leaving the dregs of wine in a wine bottle out and available. The concept of each method is to leave an attractive, sweet-smelling bait out for the fruit flies near my fruit bowl, in a vessel that then traps and drowns them.
The Bait
To keep this test even and fair, I used the same bait in each trap. I used about 1/4 cup of apple cider vinegar topped off with a few drops of liquid dish soap. The theory is that the vinegar smells irresistibly sweet to the flies, they fly into the traps, and then get their wings weighed down with the dish soap.
The Testing Criteria
I set up each of these methods on a Monday morning then placed them side by side in the same place in my kitchen. I put them on a windowsill next to some ripening bananas and a few chunks of watermelon to really up the ante. I checked back in with each method on Friday afternoon to evaluate how many fruit flies they had each dispatched to its eternal rest.
1. The Easiest (and Least Effective) Method: The Wine Bottle
Let’s start with the lowest lift: simply leaving the dregs of one’s wine out in a bottle with a little bit of dish soap. This has the advantage of really no advance preparation; just a little sacrifice of that last quarter glass of wine. I added a few squirts of dish soap.
Overall, this was not a very effective method. The wine bottle caught a few fruit flies, but it was four or five at most. I also didn’t like leaving a big, tall wine bottle out on the counter; it felt obtrusive and like it could be easily knocked over.
- Ease: 9
- Attractiveness: 4
- Effectiveness: 2 (only 4 to 5 flies at most)
- Overall Rating: 5
2. The Most Complicated Method: The Paper Cone in a Jar
The second method I tried used a classic Mason jar as the trap. (Three of these methods use a jar; you can use a Mason jar or a cleaned-out spaghetti sauce or peanut butter jar. Any jar, really!) To trap the flies you roll a piece of parchment or plain paper into a cone and insert it into the top of the jar, with the bait (apple cider vinegar and a bit of dish soap) below.
The theory (I think) is that the cone amplifies the scent of the vinegar and then makes it hard for the flies to escape.
Well, it was hard for me — maybe I’m just super uncoordinated and non-crafty, but rolling the cone was weirdly difficult? And then it didn’t even work; there were very few flies caught in this jar. I was hard-pressed to find even a few.
- Ease: 2
- Attractiveness: 5
- Effectiveness: 5
- Overall Rating: 4
3. The Ugliest (and Weirdly Ineffective) Method: The Plastic Wrap-Topped Jar
The third method stuck with the jar but instead of topping with a weirdly difficult cone, you top the jar and bait with a cover of plastic wrap. I rubber-banded the plastic wrap on, then poked a few holes with a fork for the flies to get in and out.
To my surprise, there weren’t many flies in this trap when I went to check. Maybe eight to 10 swirling around. It’s possible that the holes I made were too big and they were able to get out, or that the plastic wrap interfered with the smell.
- Ease: 9
- Attractiveness: 1
- Effectiveness: 5
- Overall Rating: 5
4. The Most Classic (and Our Winner) Method: The Jar with Holes in the Lid
To be honest, our final method (and our hands-down winner) was the one I was also most dubious about. In this method, you take a Mason jar and punch a few tiny holes in the lid with a hammer and nail. My husband did this for me and the holes seemed really small — way too small for flies to get in.
But I guess fruit flies are really tiny because when I went to check this trap at the end of the week, it was FULL of dead flies. Seriously at least 50 — I couldn’t count them all! (So gross, and so satisfying at the same time!)
This was also was the option I felt best about leaving out on my countertop because the lid was screwed on tightly and even if I knocked it over, the tiny holes wouldn’t let much out. My next goal is to find an opaque or dark-glass jar so I don’t have to see those little flies swimming around.
- Ease: 8
- Attractiveness: 6
- Effectiveness: 10
- Overall Rating: 8
Between this and the other few tests, fruit flies have basically disappeared from my kitchen on these hot, sticky, fruit-filled August days, and you really can’t beat that for results.
OK, what did I miss? Is there some trap I should have tested? Do you have another DIY method you feel is more reliable? Tell me in the comments!