I have a couple of recent observations that might add to this discussion.

Re the Russians, I've been following mite levels in a group of about 30.
 Most keep mites low, but in one, current mite wash is 25 mites per 100
bees.  My Italian stock would start to crash at that level--the brood would
be shot.  But in the Russian, the brood is still solid and beautiful, with
no sign of DWV in either adults or pupae.  This observation brings home the
point that the problem is not so much varroa, as lack of resistance to DWV.

Second observation.  I visited a yard of 6 colonies in Southern Calif a
couple of weeks ago.  They hadn't been treated.  The first 5 colonies had
greatly reduced brood nests, and were being overrun by mites and DWV.  But
they had made honey.

On the other hand, the last colony was a bit "touchy."  It was half feral.
 It had beautiful wall-to-wall brood.  But hadn't made honey.

The local beekeepers tell me that hived ferals (read partially Africanized)
survive fine without treatment.  My very limited observation would tend to
support.  But they can be an unworkable bee when in a large colony.
-- 
Randy Oliver
Grass Valley, CA
www.ScientificBeekeeping.com

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