posted 6 years ago
Hi Rob,
If the flies are flying off, then you are loosing some nutrient value, but not much. Worms will do the same thing, feeding at night, sneaking in unnoticed, yet the castings they leave behind are worth it. I personally wouldn't let it bother you, as they are taking a small amount, yet leaving their frass behind, which is a valuable asset. They are also speeding up the breakdown process, and probably aren't taking any nutrients that wouldn't be leaching into the ground anyway: as they will help soak up the moisture from the vegetable waists, that tend to be very wet without brown carbon sources to help soak them up. That wet matter just leakes into the ground anyway, and rain leaches alot to, if your compost isn't covered. Hot composting could help cure that infestation. You could also check your carbon ratio, if your not properly building your compost, and if that doesn't help, maybe your bin isn't big enough to get to pasteurization temperature. I wouldn't worry about the flies though, it's most likely a symptom of some other issue your overlooking. With that said, if it still isn't resolved, it can sometimes be more trouble that its worth fighting against nature, but if you feel you must: and those other solutions don't help. Food grade diatomaceous earth, may be worth looking into. Hears two ideas, kind of grasping at straws, for anyone who wants to research: there also may be some paracitizing bacteria strains, like BT, that host in solder fly larve, or some paracitizing fungi in the cordicepts family, that may work; however, on those last two I'm just theorizing, and it would take resurch to confirm that, potentially even testing.
Hope that helps!