I coauthored a  review and a caution on the issue of Varroa travelling
on alternative hosts, including wasps and flowers, also betles. The
review, co-authored with Laverty and Denmark was published in BEE
WORLD. The remarks about Varroa possibly travelling with bumblebees
is most alarming, and was noted as a possibility in our review. I can't
remember the volume &  issue of BEE WORLD, but what other organ for
publication would be appropriate to such oversight! The information was
also published in Canadian Beekeeping. 1991
I would add that our review did elicit some aapparent annoyance among
parties with vested interests in bombiculture.
 
Cheers, Peter Kevan, U of Guelph, Canada