>
> >Makes perfect sense,  the question to me from a practical stand point,
> on both issues is the Number,    Are they tolerant from say zero to 20%?
>

For typical commercial EHB stocks in the U.S., tolerance appears to be
limited to an infestation rate of either the brood or the adult bees at
less than roughly 10%.  After that, DWV tends to go epidemic.

>
> >A common definition from an industry standard would go a long ways.


You're asking good questions Charlie.  Harris and Harbo explained the
necessary standard.  It has to do with the intrinsic rate of increase of
varroa during the broodrearing period.  For truly mite proof bees it needs
to drop from a daily rate of 0.021 to the low single thousandths (perhaps
0.003), depending upon several other factors, such as grooming.

>So would it be correct to say that 'tolerant' bees are able to cope with
the viruses etc that are associated with varroa whereas resistant bees
would have an impact on the mites themselves - either by physically
attacking them (e.g. grooming) or by suppressing their ability to reproduce?

Yes!
-- 
Randy Oliver
Grass Valley, CA
www.ScientificBeekeeping.com

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