How do I get rid of flies?
One of our most frequently asked questions is “will there be bugs?” While we’ve designed a chamber system that minimizes the risk of creepy crawlies there are preventative measures you can take to further distance yourself from those pesky bugs.
Composting is all about maintaining a comfortable environment for the microbes and unfortunately, their ideal conditions can also be facilitative for insects; so we’ve taken care to design a system that is difficult for them to infiltrate. The flyscreen mesh on the ventilation caps and the constant airflow from the fan creates a draught that hinders the fly’s ability to hover and settle on the compost pile comfortably. The mesh obviously is also a barrier between the compost and the outside world that, with the double-walled design, prevents bugs from sneaking in while your chamber is collecting or resting.
But as well as we think we’ve done there is the possibility of a bug problem when conditions are right – when it’s hot and humid especially. We’ve created this comprehensive guide for you to identify your flies as well as preventative and reactive measures against them.
Know your enemy
It’s going to be important to identify the type of flies that you are seeing, because they will all have different habits and life cycles. Depending on the type of fly, your tactics may change. For example, you can’t just treat the composting toilet but also surrounding areas where they could be breeding or feasting.
That is why the first step is to identify what type of flies are hanging around your compost toilet; the most common pests that we have encountered are Fungus Gnats, Vinegar Flies, and Soldier Flies. Below is a quick reference guide to the key differences between these breeds of flies:
| Fungus Gnats | Vinegar Flies | Soldier Flies | |
| What do they look like? | Small flies up to 3mm, black or dak grey in colour | Small flies up to 4mm, yellow or brown in colour with distinct red eyes | Large flies up to 22mm, dark blue or black in color |
| Where do they lay eggs? | In wet soil and organic material (i.e. decomposing, fermenting products and waste components) | Moisture and liquid residue (i.e. damp sponges, small pools of water, and constantly damp places) | Dry surfaces near organic material, especially small crack and crevases |
| What is the average lifecycle? | 28 days | 10 days | 44 days |
| What do they eat? | Fungi and plant roots | bacteria and yeasts (usualy associated with rotting fruit) | Rotting food and manure |
| Why are they attracted to my composting toilet? |
They will be attracted to the moist composting pile to lay their eggs. So treating the compost pile will affect the whole lifecycle. But the compost pile isn’t a reliable source of food because there shouldn’t be any plant matter and only residual amounts of fungi (as part of the microbe mix) |
The adult flies will be attracted to the bacteria and yeasts of the compost pile (as part of the microbe mix). However, they will be attracted to nearby damp places to lay their eggs, such as the leachate drain or condensation in the ventilation pipes. They only hover around the compost pile as a food source. |
They will be attracted to the compost pile and the humanure as a food source. But as they are large in size, they cannot easily enter the chamber. They may lay their eggs nearby, in small cracks like crevasses of a wall. While trying to visit your compost pile as a food source. |
Methods and products for keeping flies out
General compost toilet maintenance
Firstly and most importantly: do not put food scraps into the toilet as that will be a very attractive food source to the flies and actively attract them to your pile! It’s as simple as that; we cannot recommend adding food scraps to your toilet’s composting pile for several reasons but the first and foremost is that it will attract bugs and flies moreso than anything else.
Next up is the fan and ventilation. Flies don’t like the constant airflow from the fan because it makes it difficult for them to settle; it’s very common to see an infestation begin just after a fan has stopped working. It’s a safe bet always to have a spare fan on hand, so you have a consistent airflow with no fluctuations.
The ventilation piping should be clear of blockages, including reducing horizontal sections where condensation can pool. There should also be no dips or loops in the flexi hose – trim it to length if required. Make sure the vent cowl, or equivalent, is secured to the vent pipe correctly, and remember that vinegar flies can penetrate standard flyscreen so try to use midge mesh where possible.
Wet conditions are very attractive to flies, so once you’ve checked the ventilation pipes it’s time to check the moisture content. If the composting chamber is full of liquid and everything is soggy, this can be indicative of a drainage issue. Otherwise, try adding some extra bulking agent and running the system dryer than you previously were to try and dissuade the flies.
Using fly traps can catch adult flies before they have a chance to lay eggs, which helps disrupt the breeding cycle; but they are also useful to locate where flies are congregating as well as creating a benchmark to gaue any increase or decrease in numbers.
Deterrents
Be careful what products you use around your composting pile. Just like antibacterial cleaners will kill your culture of microbes, so will some insecticides!
The best preventative measures are Diatomaceous Earth and Yates Tomato Dust because they will create a hostile surface for the flies. When using these you’ll want to follow the safety instructions first, turn off the fan and add a small handful to the chamber from the pedestal. Having the fan off will give the material a chance to settle instead of immediately being disturbed by the airflow; this will prevent the flies from landing on the compost heap and laying eggs. The results of this may not be apparent immediately; instead, the best results will be after a few days left undisturbed so it is more effective on out-of-service chambers.
Removing flies from cmpost
Our best recommendation to react to an infestation of flies is a pyrethrum-based insecticide. Direct contact with a pyrethrum-based product will kill flies, without harming your culture of microbes! This, in conjunction with good maintenance and the above preventative measures, will start to reduce the number of flies.
Just remember that you need to treat the entire lifecycle and treat the surrounding areas. Because it only takes a few flies to lay eggs and the population starts to increase again.
In the in-service chamber
Firstly, you want to turn off the vent fan temporarily, otherwise, the insecticide you’re putting in the chamber will get sucked out. Then:
- Liberally spray into the bowl and the chamber.
- Immediately cover the toilet bowl, this is most effective when using plastic wrap to seal the opening. This traps the insecticide spray inside.
- Leave for at least 10 minutes to let the pesticide settle and affect all the flies inside. Then you can turn the fan back on.
- Do this every day until you have broken the lifecycle of hatching flies.
In the out-of-service chamber
If you have the ventilation connected to your out-of-service chamber, follow the in-service chamber instructions. Otherwise,
- Place a layer of diatomaceous earth over the top of the pile, to create that hostile surface that harms the flies.
- Follow this with the insecticide spray.
When you’re closing the chamber back up, make sure to spray any potential hidey holes that the flies may also be in nearby as the flies won’t only be in the compost.