A guide to removing flies from your composting toilet

Application schedule

To remove and manage flies from your composting toilet, you can create an effective treatment schedule using neem oil, pyrethrum, and diatomaceous earth (DE). Here's a plan to help you manage the infestation quickly:

Day 1: initial treatment

Neem oil

Follow the instructions on the product label to dilute neem oil into a spray bottle. Spray the entire surface of the composting pile and surrounding areas, particularly near the toilet or any other entry points you can identify.

Neem oil acts as a repellant and interrupts the lifecycle of the flies

Pyrethrum spray

Use a pyrethrum-based insecticide spray in the areas where flies are the most active, this is usually around the top of the composting pile.

Pyrethrum works as a fast acting contact insecticide, killing the adult flies. 

Diatomaceous earth (DE)

Sprinkle DE liberally over the surface of the composting pile, focusing on areas where flies are most present.

DE kills flies by damaging their exoskeleton, causing them to dehydrate. Be careful and wear a protective mask and not inhale the dust when applying.

Day 3: ongoing treatment

Reapply neem oil and pyrethrum spray as needed. If you still notice a high number of flies, focus the pyrethrum on high-traffic fly zones. Add more DE to where the previous layer has been displaced, covered, or if flies have emerged. 

Introduce sticky fly traps where there is persistent high-traffic fly zones to help catch the adult flies. 

Day 5: follow up treatment

Continue to reapply neem oil and pyrethrum in affected areas. Reapply a layer of DE over the composting pile to ensure that any newly hatched flies are exposed to it. 

Weekly: ongoing maintenance 

Neem oil spray

Apply neem oil weekly to prevent new infestations by disrupting the fly breeding cycle

Diatomaceous earth

Continue to sprinkle a light layer of DE on the composting pile weekly, to help maintain a fly-free environment 

Pyrethrum spray

Only use pyrethrum only when adult flies start to become a problem, as repeated use can cause flies to build a resistance. 

Additional tips

Maintain a consistent moisture level in the composting pile. If it is too wet, flies will be attracted to the moisture to lay their eggs. It is important to balance wet and dry materials being added to the toilet to balance the moisture levels.