Sorry for asking David if he used Apistan strips. Did a quick
search of the archives and found that David wrote-

"I had to leave our strips in last year and we've had no
problems. As
an aside when Varroa first hit Ontario it was advised to leave
the
strips in for the first winter!"

-which was a part of the discussion last month on leaving the
strips on all winter. So it seems he uses them.
I repeat, until a good study comes along, FGMO is not proven.
Many of the posts during the great FGMO flame wars ran along the
same path.
"It works and I use Apistan and the bees make it through the
winter so it was because of FGMO." Often the use of Apistan was
omitted until pressed and then admitted.
The only studys I have seen that were independent of Dr. R showed
FGMO a failure to control varroa when used by itself.
I throw on a oil soaked towel in the hives every year. I also use
Apistan every year, but only in the fall. I did not lose hives
before I put the towels in and I have not lost any since. But it
is more for tracheal mites than varroa.
By the way, have you heard about lice droppings, very hard to
accumulate, but I know someone who knows someone who says it
kills varroa on contact and has not lost a hive to varroa since
he started using it and Apistan strips.
I will conduct a study this winter using lice droppings and let
you know how well my bees overwinter. Probably apply it at the
same time I put in the Apistan strips.
Bill T