Guide

Down with the beasts! How to effectively combat fruit flies

22/7/2022

Translation: Megan Cornish

Ripe fruit and warm weather are a fruit fly’s dream, but, most of the time, we humans don’t tend to like them. So, what’s the most effective way to keep them at bay?

I hate to break it to you, but you’ve definitely eaten a Drosophila egg. Or rather a few hundred. Because July and August are when the fruit fly is at its happiest and reproduces diligently. A Drosophila melanogaster, to give it its scientific name, can lay 400 eggs in a productive night, preferably on ripe fruit and vegetables. So, if you then bite into an apple, you also get a small protein bonus. But that’s not too bad, and you can’t even taste it.

Still, the thought alone makes me shudder. And it’s not just me. Google search trends show that from July, and especially in August, many people want to find out about the different types of fruit flies. They’re pretty much all the same insect: two to four millimetres in size, brown to yellow in colour. And just really annoying.

The question for many, therefore, is: what’s the best way to deal with them?

Year after year, the Google search trend for the term fruit flies shows a sharp upward trend in summer.

Preventative measures

There is preventative action you can take against the little pests. Even if you can’t completely prevent encountering a fruit fly in summer, you can keep infestation as low as possible with a few basic rules.

Wash fruit and vegetables after buying

Most of the time, you bring the enemy into your house yourself. Ripe fruit and vegetables are the ideal home for fruit flies and their eggs, from which they hatch after about ten days. If the eggs are already in your apple or courgette, washing them won’t do much good. But if they’re not yet there, washing will reduce the odour of the ripe fruit, which would otherwise attract insects.

The place where fruit flies feel at home: a fruit bowl.
Source: Wikimedia Commons

Eat ripe fruit – or hide it

If you deprive fruit flies of their livelihood, they won’t want to stay. So, as nice as a fruit basket looks in the kitchen, you should avoid using it if you want to prevent fruit flies. You’re better off putting your apples, cherries or apricots in the fridge, or at least in a paper bag. If you don’t want to do without your decorative fruit bowl, cover it with mesh. Although this only helps to a limited extent if, for example, the cover has feet which prevent the mesh extending right down to the bottom of the bowl. Although I can recommend these:

Anyway, the best option is eating fruit and vegetables straight away and not leaving them lying around for long, which means that, ideally, you should only shop when you need something.

Avoid organic waste and open soft drinks

Even if it’s tedious, in summer you should take your organic waste outside immediately and not wait until the container is full. Fruit and vegetable waste is an ideal breeding ground and food source for fruit flies. The same applies to soft drinks that are left open. It doesn’t matter whether it’s a glass of apple juice or an open bottle of cola – the scent attracts fruit flies. So, put them away!

Use fly screens and close windows

As mentioned above, it may well be that you brought the fruit fly plague into your home yourself. But you could also be innocent and the fruit fly could have got in through an open window. Keeping the little pests away is difficult, but it’s possible. You need a lot of discipline when it comes to door and window management. Always keep them closed, or, if they’re already open, put a fly screen on them. Choose one with as tight a mesh as possible, otherwise the Drosphila will likely squeeze through at just two millimetres in size.

tesa Insect screen COMFORT for windows, with Velcro tape, self-adhesive, without drilling

Fly screens

EUR17,21

tesa Insect screen COMFORT for windows, with Velcro tape, self-adhesive, without drilling

Fly screens

Quantity discount

EUR13,73 per piece for 2 units

tesa Insect screen COMFORT for windows, with Velcro tape, self-adhesive, without drilling

120 x 240 cm

Are there already fruit flies in the house?

Sometimes prevention doesn’t work. Somehow, the fruit fly made it into the house or you brought the eggs in, from which a battle squadron is now rising and buzzing around your head. Now you have to fight the invaders.

Lure them into the glue trap!

Sticky traps are a classic way of fighting fruit flies without chemicals. They attract the insects with pheromones and then hold them to the sticky surface until they, well, die there.

Animal trap

Neocid Fruit fly trap

Animal trap

Optimum Fruit fly trap

Animal trap

Recozit Fruit fly sticky trap with long-term effect

Drown them in fruit fly ambrosia!

Death is also the goal of method number two. Here, too, the first step is to attract the fruit flies, but then they are supposed to drown. In order for this to work, the key ingredient in the lethal cocktail is detergent, because it breaks the surface tension of the water and this is the only way the fruit flies can walk on it. The mixture is two tablespoons of water and three tablespoons of fruit juice (e.g. apple juice), plus a tablespoon of vinegar, some sugar and a few drops of washing-up liquid.

Technically, it doesn’t matter what you put the mixture in, but I prefer it if I don’t have to see the floating fly corpses, so I like shapes like this:

Animal trap

Kela Fino

Swissinno Fruchtfliegenfalle mit Lebensmittelköder 1er

Animal trap

EUR18,90

Swissinno Fruchtfliegenfalle mit Lebensmittelköder 1er

If you’d prefer it to be clear, we also have this fruit fly trap in the shape of an apple – it might sell quite well in apple-loving Thurgau. Incidentally, the number of searches for «fruit flies» on Google is the highest there by some margin.

If mixing a drink for the fruit fly hemlock cup is too tedious for you, here’s the lazy option: just leave a little bit of wine in the bottle and place it where you suspect the fruit flies are, for example by the fruit basket. The insects will be unable to resist the smell of the wine, climb into the bottle and then never get out of it alive. Luckily these annoying critters don’t have big brains.

Animal trap

EUR15,01

Esschert Design Fruit fly trap apple

Be a good guy and catch them alive!

Those who don’t want to kill for moral and ethical reasons can also catch fruit flies alive and then release them back into the fresh air. This type of trap also has the charm that a small piece of fruit is sufficient as bait, so you don’t have to mix anything or buy something to attract them with.

Animal trap

EUR17,19

Vincentes Frubby

Do you have any other tips for controlling fruit flies, or whatever you call them? Let me and the Community know in the comments.

Header image: Martin Cooper/Wikimedia Commons

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Martin Jungfer

Head of Content

Martin.Jungfer@digitecgalaxus.ch

Journalist since 1997. Stopovers in Franconia (or the Franken region), Lake Constance, Obwalden, Nidwalden and Zurich. Father since 2014. Expert in editorial organisation and motivation. Focus on sustainability, home office tools, beautiful things for the home, creative toys and sports equipment.

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