Hi Kerry Concerning the group of hives treated in the fall, the "symptoms" you describe suggest to me the following: that the queens would have disappeared (probably killed by the bees) following the formic acid treatment; that the colonies would have raised emergency queens from the brood left; (was there any brood left at the time of the treatment?) that these new virgins could not mate because because of the poor weather and maybe the absence of drones in the fall; (what are the weather conditions like at the time of the year the treatment was done?) and finally they became drone layers. How extensively is the formic acid used to control the tracheal mites and the varroa mites in British Columbia? Do you still see it as a promising tool to control the mites? I heard from beekeepers from the canadian Prairies that there was a specific range or temperature to use the formic. I heard that queen losses would occur only when the formic was used in warm weather. What is your experience on this. Do you get many reports of queen loss? I whish to use fluvalinate and menthol as little as possible when the mites get in our hives. I was seeing formic as a good prospect. The members of club API here in Quebec would like to experiment with it with the help of Peter Keating. We should keep in close contact on this. I would be pleased to translate and publish in our bee magazine any material on this subject. Winter is still present here: still 24 inches of snow on the ground in many places around here! ********************************************************************************* ********** Jean-Pierre Chapleau phone: (819)828-3396 1282, rang 8, fax: (819)828-2248 Saint-Adrien de Ham, QUEBEC, CANADA Canada, J0A 1C0 [log in to unmask] ********************************************************************************* ***********