The strains of Bacillu thuringiensis that aid in control of mosquitoes occurs naturally, but usually in such small numbers that they do not do a good job of control. Growing those strains requires, as best as I can find, controlled laboratory conditions.

BtI is so very, very inexpensive it should be a part of most homeowner's arsenals of safe but effective insecticides. And it only takes a tiny dunk to control a huge area for a long time. Not hardly worth the effort to try to manufacture them even if you could. One card of two lasts me a whole season.

I agree that the investment in equipment and space would be much more costly than fuel, material and taxes.

Dan