As has been pointed out, we are dealing with more than one strain of
varroa. It is interesting that the Russians use heat to combat Varroa, so
it would seem that the cooling effect of the hive ventilator would do
little to combat the far-east varroa and might be counter productive.
There were some studies done on dark painted hives to see if the additional
heat load had any effect on Varroa. The results were fairly typical when it
comes to Varroa. Yes, it had an effect on reducing them in some hives and
no, it had little effect on others. Ambiguous, but the conclusion of the
researchers was that it made little difference.
Bill Truesdell
Bath, ME