We have composting toilets at summer cottages and always find hundreds of dead flies littered about the bathrooms each spring. Everything is screened so we cannot think where the flies are getting in. The thought has occurred to me that it may be that the the flies are laying eggs in the toilet and would explain the many flies; they are not “getting in” they are “hatched in” the bathroom. Is there any sense to that and if so do you have a spray or powder that we could spray into the composting toilet that would kill the fly eggs?
Composting toilets will attract all kinds of insects and the flying kind can get in many ways. Once inside the bathroom, they’ll surely find the toilet, get inside and lay some eggs. And when these eggs hatch and develop, you’ll start seeing swarms of flies emerging from the toilet if a cycle hatches during a visit! No doubt one or two are getting inside when you visit and though you don’t see any activity when you leave, there is no doubt eggs and larvae around that will soon mature and become the adult flies you’ve been finding.
To prevent this from happening, there are a few options. The simplest is apply a coat of DIATOMACEOUS EARTH inside the toilet when you’re done with a visit and are about to leave. Use a HAND DUSTER to make the application. The layer will not affect the activity below it but will act as a barrier from any intruders coming in from above. And if you plan on staying at the cottage for a week or longer, you probably would want to apply some during your stay to make sure a new fly cycle didn’t start during your visit because once you show up and start using the toilet, it’s just a matter of time before something does start to happen.
Diatomaceous Earth: https://www.bugspraycart.com/insecticide/dust/diatomaceous-earth
Another option would be to set up an AUTOMATED FLY MACHINE which can be equipped with a FLYING INSECT KILLER. This would handle any kind of flying pest and refills will usually last a month or longer depending on how you set the machine to operate.