This is partly in response to Matt's post. I tried all the methods suggested and more -- flour, bright lights, water, separating cultures, etc.
I eventually decided to go a chemical route. I could not find any pest strips that did not have an odor. I consulted our veterinarian about what could kill mites by contact and not release any fumes that could affect the flies or anyone else in the house. He suggested Frontline (fripronel). It is made for fleas and ticks on dogs and lasts for a month.
I keep my cultures in a shallow rubbermaid container. I take the container outside, spray the bottom and inside sides with Frontline and let it dry compeletely. Just to be safe, I wait a day. I then bring it inside and place the cultures in the container so that any migrating mite would have to cross through the treated surface.
I have not had mites since! It seemed risky, but like I said, nothing else had worked. The flies have produced fine and the frogs are fine. There is no chance of an escaped fly bringing the stuff back into a culture since it kills any escaped flies.
Chris D.

