Adony Melathopoulos wrote:
 >The most widely used organic acid was formic acid, which was accounted
for approximately 80% of organic acid use (formic, oxalic and lactic
acid).  Although heavier reliance in synthetic miticide use was observed
among beekeepers with more than 200 colonies, fewer than 40% of larger
Danish beekeepers used synthetic acaricides.
>
> Similar trends have been reported in Ontario, Canada, where a terrific effort be beekeepers and their technology transfer group greatly increased the use of formic acid.  Over 80% of Ontario beekeepers are reported to use formic acid.

My understanding is that the Ontario Beekeepers use a combination of
Formic and Apistan, not Formic exclusively - which I note you did not
say but it could be infered. It is a rotating schedule to lengenthen out
Apistan's life. At least that is what I remember from Medhat's comments
at last year's Maine State Beekeepers meeting.

Plus, in Europe, where resistance is fairly widespread, I also would be
using the acids since the synthetics might not or would not be
effective.

Oxalic Acid has been used successfully by a beekeeper in Maine last
year. Got good mite drop from Cumophose resistant bees. I am awaiting
his results this year.

Bill Truesdell
Bath, Me.