Two questions in response to my good friend Bill Miller's
suggestion to NOT treat feral swarms for varroa.
 
1.  How do know the swarm is a feral one and not from a kept colony?
2.  How do you prevent any varroa from that swarm
from serving as a close and perhaps potent source of
infection for your own colonies.
 
I remain to be convinced that not treating feral swarms
is generally a good practice for most beekeepers.
 
A final comment.  There is lots of discussion on selective
breeding of queens to come up with a resistant strain of bees.
I am sure there must be considerable variation in the genetics
of the mites - ie some less and some more virulent.  Is this
an area that is receiving any attention?  Could a more
innocuous mite be produced that our bees could better
tolerate?  Its not obvious how this would work, given
the life style of the mite, but it may be an aspect that
could help.
 
Wayne Esaias