Greetings!
I have done this, so I can tell you how. One has to add bees and/or brood to the colonies at regular intervals. In this way, colonies with high mite populations can be maintained for years. It is similar to maintaining queenless cell-builders. It may be expensive but it will work.

However, does anyone know how long it would take for "evolution" to generate mite-resistant bees in this manner? I don't think we can even speculate how long that would take! Hence, the usual route is to carry on selective breeding, rather than to sit back and wait for nature to come up with a solution to a problem which is essentially man-created.

After all, Apis mellifera probably would never have gotten thoroughly infested by varroa were it not for 1) the importation of Apis m. into Apis cerana territory, 2) the keeping of so many colonies so close together, 3) migratory beekeeping and shipping of bees overseas.

I suggest beekeepers must give their full support to efforts world-wide to develop mite-resistant bees. Buy these queens and use them! Do not raise queens from "local" bees or simply let the bees requeen themselves. (My $.02)

pb