Joe, the range of BSF is still a mystery to me. The only limiting factor is that they can't freeze, but I would think that's true of other fly species as well. Furthermore it does get down below 20 degrees in south Georgia but the wild population doesn't get wiped out.
I've read that the development of the larvae slows down considerably in cold weather, so it seems they time their emergence with warm weather. I didn't see any adult BSF around my place until several weeks after the last frost. They had to survive as pupae somewhere during that subfreezing period, otherwise I wouldn't have seen adults later on.
Some researchers report that BSF can be found nearly everywhere on the continent, but specific data is hard to find. It's very possible that BSF are relatively near where you live, but just not in your immediate area. I doubt that they will find your scraps if they aren't pretty much down wind of it.
As a long time member of the Pond Boss family you qualify for a free BSF seeding kit (while they last). If you want to try your hand at raising some, just send me a PM with your shipping address.
