I think that it safe to say that both Mike and Sol are advocating the same type of natural selection carried out in the original Gotland and Avignon studies. No intervention by man.
I'm taking a different point of view for treatment-free beekeeping.
Use the Honeybee's own strengths to produce resistant bees.
What I find to be perplexing, is this: people summon the power of 'Evolution by Natural Selection', however, they reject the mechanism for evolution provided by 'nature'.
Honeybees are naturally transgenic. Please get over it, and put it to good use.