Our school hive from a package this spring has shown zero signs of mites all summer. I would have thought this next to impossible. This same hive swarmed in June, and I caught the swarm and brought it home to tend it. By the end of the summer, this swarm nuc had a few mites (as does my other hive of two years). I combined the swarm with its mother hive a couple of weeks back as neither seemed strong enough to winter over, and now this recombined hive has dropped a few mites...too bad, but interesting that at one site they somehow managed to avoid them.
What method were you using to test for mites?
Glen
I use the same on all the hives - an oiled sticky board under a SBB.