>>Russians has been dealing with oxalic acid long time before West Europeans...Their primary recommendations...were
vaporizing (sublimation) and spraying (late 1980's). <...> They did not recommend OA in our days. I suspect that they use it, but not
on large scale.

What is the most popular treatment method for varroa in Russia today then?  Any Russians on Bee-L?  From what I've read, except for Asia, they have had varroa the longest.

>>Why? Yes, there is a some anegdotal reports of varroa
resistance to OA. But... Primary reason is special beekeepers desease
(attack: kidney, result: stones). (We are talking of long term exposure!)

I can understand the concern about inhaling OA vapors but think the OA liquid drip method is very safe with basic precautions.

>>Why sublimation metod is not recommended?
Because it leaves (contaminates) around 60% of OA crystals distributed at all surfaces of hive (inside)!

I use metal-screen bottom boards.  I would have to seal the bottom to contain the vapors.  And the acidic vapors could possibly attack the metal screens.  The OA liquid solution ends up [mostly] on the bees.

>>beekeepers use twice smaller quantity of OA dihydrate, when they use sublimation metod, and why this method is much better for varroa kill, but...

The research reports I've read showed similar effectiveness as far as varroa kills with both methods.

Waldemar

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