>
> > The average percentage of bees drifting from untreated hives infested
> with varroa into neighbouring treated hives did not exceed 3%
>

I wouldn't put a great deal of stock in that 3% number, as there are a
number of issues with the experimental design.  The amount of drift was
checked at 14 days after marking the newly-emerged bees, which would be
early to expect them to be flying much.  Plus less than half the marked
bees were recovered, either in their parent hive or in any other hive.

I suspect that the actual amount of drift exceeded 3% by some factor.
Let's arbitrarily adjust it to 5% so that we can do some math.

 If an infested colony contained say 40,000 bees at 50% infestation rate of
the adult bees (reasonable for a collapsing colony), then that hive would
contain 20,000 infested adult bees.  If 5% of them drifted during 2 weeks,
that would be 2000 mites being transferred to other colonies by drifting
alone (not counting robbing).

2000 mites being transmitted to adjacent colonies over a 2 week period of
time is still a lot of immigration.

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

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