Dee and All

If I can respectfully suggest, your proposed experiment will do nothing to
clarify in the mind of sceptics whether or not 4.9 is useful in controlling
Varroa.  The experiment Allen suggested is crucial to convincing others that
4.9 is a useful addition to IPM for Varroa, but if there is no *direct*
evidence people will be slow to take it up.

Why will your experiment fail to make anything clearer?  It is obvious to
everyone that drone brood is a better home for Varroa than any size of
worker brood.  But the success you claim for 4.9 is not, I assume, because
small bees stop making drones?!  Much more likely would be that the small
cell size inhibits the mating of the mite in a cramped cell, or that the
small cells somehow awaken unusual hygienic behaviours as some have
reported.

What is really needed?  Moving some of your resistant bees from 4.9 back to
larger sizes in a way that preserves the normal ratio of workers and drones,
in colonies that start with similar mite loads, and following through at
least one season the performance of those colonies.  Maybe Bee-L
participants have a better idea of how to do this that I have, remembering
that you need everything except comb size as equal as possible.  If you
shake an entire 4.9 colony into 5.4 comb will it adopt 5.4 worker cells as
worker and '5.4' drone cells as drone?

Why is this needed?  You are making big claims for 4.9 and it is possible
that this is one of the best ways to move to sustainable beekeeping.  It is
also possible that 4.9 is largely irrelevant and that other factors give you
the resistance to the mite.  At the risk of repeating old arguments, the
process of allowing a crash in numbers of colonies due to Varroa and then
breeding from survivors must mean that your bees are now inherently more
resistant to Varroa.  What is not clear is the relative contribution of
genetics and 4.9 - and only those beekeepers making progress with 4.9 can
perform those experiments and tell us the answer!

all the best

Gavin.