I attended the Texas Beekeeper Association summer meeting in  Paris, TX a
couple of weeks ago and met a gentleman who claimed to have solved his
varroa problems. He said to take 4 pounds of powdered sugar and 6 ounces of
garlic powder (not garlic salt) and mix them together. Dust the entire hive
with this mixture; I don't recall how much he said to use, I believe it was
not the whole batch but just enough to coat the bees.
I have not yet tried this but he was very adamant about his success. I know
the powdered sugar will dislodge the varroa but I don't know what part the
garlic plays.
This gentleman was not part of the official program and was an attendee as
was myself. I want to pass this info on only FYI.
Bob Young
Lindale,TX