How to make a fruit fly trap

If you have an empty jar or bottle to hand, you can make a fruit fly trap in less than two minutes. I made two fruit fly traps today, after noticing a few of the little oiks bobbing around the kitchen.

Fruit flies get around, don’t they? All it takes (in my case) is one lonely, soft banana, at the bottom of an otherwise empty fruit bowl. And SHAZAM, there they are. To be fair, I think there are plenty of fruit flies around in my part of the world at the moment: here, the fruit is ripe on the trees and the brambles are stooping beneath the weight of all those big, juicy blackberries.

Anyway, making a fruit fly trap is super-easy. Here are the two I made, one from an old milk bottle and one from an empty jam jar:

Because you can use a variety of different containers and materials, I guarantee that you will already have everything you need to hand, and you won’t have to spend another penny. Here is what to do:

How to make a fruit fly trap

You will need:

• A piece of paper. I delved into my collection of wallpaper scraps, but any paper will do. A piece of A4 is fine.
• Sticky tape
• Washing up liquid
• An empty jar or bottle

And at least one of the following ingredients: 

• Piece of fruit – the older and gunkier, the better
• Apple cider vinegar
• Red wine – old or new
• Balsamic vinegar

Instructions:

1. Make a paper cone and secure with sticky tape. Check that the the cone will fit snugly into your bottle/jar. 
2. Make sure you have a small hole at the thin end of your paper cone. If you don’t, pinch off the end of the cone with a pair of scissors.
3. In the bottom of your jar/bottle, place/pour one or as many of the above ingredients as you have. If you are using vinegar or wine, add a little washing up liquid and mix.
4. Insert your cone into the jar/bottle. If you need to ensure a good seal, tape the sides of the cone to the edge of the jar/bottleneck. (I haven’t done this here, because the wallpaper I have used is thick, but if you are using regular paper you will need to do this, to ensure the fruit flies can’t escape.)
5. Place your trap in the location where the fruit flies are plentiful. And wait…

If you have used washing-up liquid, the flies will drown in your trap: the soap lowers the surface tension of the mixture. But if you don’t want to kill them (i.e. if you are kinder than me) omit the washing-up liquid, and you can set your captured fruit flies free, instead.

There really are no hard and fast rules about how much stuff you should load your fruit fly trap with. But I will say a few things. Firstly, there is more red wine in my milk bottle than you would think from that picture – a good glug, in fact.

Secondly, if you add fruit, you’re playing  a longer game. The softer and more rotten the fruit gets, the more the fruit flies will love it. In my experience you are looking at days to catch your fruit flies, rather than hours. I also wanted to make this point because my picture shows a single, modest slice of banana inside that jam jar, and I didn’t want to mislead. I like to use banana because we usually have some about and banana pulp turns quickly, but since the picture was taken I have also added a peach pit.

You really don’t need to faff around too much with your paper cone. Any old funnel will do. As you can see from the picture above, the cone in the milk bottle is tall and thin, and it really doesn’t matter much. In fact, that bottle has snared a fly while I have been writing this post…

Homemade fruit fly traps like these should be enough to clear the occasional fruit fly flurry. However if you have regular infestations and you are DUNZO with the flies, there is a really good guide to getting rid of fruit flies here, on WikiHow, which has lots of DIY methods and fruit fly prevention tips.

A final note: if you set up one of these traps, don’t forget to clear away all the other potential sources of fruit fly food. Glug some bleach down your kitchen drains, take your food scraps out to the composter, make sure all your surfaces are clean (not that I’m suggesting they are anything other than sparkling!) and if your fruit bowl is full, bung it in the fridge for a while.