Dealing with fruit / vinegar flies around your composting toilet

If you’ve had a composting toilet for any period of time, it’s likely you’ve had a few vinegar flies (also called fruit flies, barflies or if you want to get really technical Drosophila melanogaster) buzzing their way around your toilet – well technically your composting pile. 

If you’ve found some vinegar flies buzzing around your composting toilet, it’s a good idea to deal with them sooner rather than later as they breed very quickly and the females can lay up to 400 eggs which will hatch 12-15 hours later. So if left for several days, fruit flies can become a considerable problem. 

What do vinegar flies look like?

This is where things can get a little tricky. If you take a look at (yes there is a website dedicated to flies!) you can see there’s a wide range of flies from the genus Drosophila (typically referred to as a fruit fly) and Australia has over 150 native species of fruit fly, so there’s a wide range of different flies that could be visiting your home. 

They tend to look like midgies or gnats, however, if you get up close and personal with them, you will notice they look very much like your common house fly, just a lot smaller. 

How do I get rid of vinegar flies from a composting toilet?

If you’ve come home to a cloud of fruit flies making their home in and around your composting toilet, never fear – there are several things you can do. 

Step 1 - Remove their food supply

This is the most important thing to do as if they have a constant supply of food, they’re going to keep coming back again and again. Fruit flies only need a small amount of liquid or residue to lay their eggs. The first thing you will want to do is make sure there’s nothing for them to lay their eggs in. Thoroughly clean all the surfaces on and around your composting toilet and remove any flowers or organic matter they might be using as a food source. 

Step 2 - Check your exhaust fan is working

At this point, before you go too deeply into cleaning and pulling your hair out trying to figure out where these fruit flies are coming from, it’s worth making sure your exhaust fan is working. You want to make sure you’re making the toilet an unsatisfactory environment for the vinegar flies. Even if you have a bowl of fruit in the house and the fruit flies start there, it’s likely they’re going to make their way to your composting toilet, particularly if the exhaust fan isn’t working properly (you likely would notice this anyway as your system may start to smell as air from the compost isn’t being fanned out and liquid won’t be evaporating properly). 

Step 3 - Don’t kill your compost in the process of killing vinegar flies

What you definitely don’t want to do is start spraying or adding bug spray, bleach or any other insect killer on or into your compost pile as this will kill all the good bacteria and bugs in your composting toilet (which will lead to a whole bunch of additional problems!).

Step 4 - Break the breeding cycle 

To break the breeding cycle of fruit flies spray the compost pile with pyrethrum-based insect spray for ten consecutive days.  It's important to remember to turn your fan off before spraying otherwise all the spray will exit the system via vent piping. Always place a layer of wood shavings or Diatomaceous earth over the top of the pile that’s in the additional chambers (chambers that are curing for example) to eliminate the possibility of insects laying eggs.

The main thing to remember with fruit flies is it’s easier to not get them in the first place so make sure you clean up any spills or overripe fruit from your home. Eliminate their food source and you eliminate the flies!

If you have any additional questions about composting toilets or fruit flies, feel free to contact us or call us today on 1300 138 182.