>Bill Truesdell wrote about dosages for aoxalic acid dripping treatments
(which i will not quote).

I have read reports and recommendations here in Sweden. Different dosages of
oxalic were compared and the recommended percentage is 3.5% in a 50/50 mix
of sugar and water. 4.2% percent was also tested. This was even more
effective on the mites, but resulted in weaker colonies in the following
spring.

The recommendation on how much oxalic syrup to drip is 20 ml for weak
colonies, 25 for medium and 30 for strong ones. This kind of treatment kills
85-95% of the mites in a broodless colony (i can present the precise figures
if anyone is interested).

I suppose the higher percentages will only work if the bees are flying all
the time, which they obviously won't be here because of cold weather. It is
essential that the bees have at least a few days of flying weather after the
treatment. Spending all winter with the oxalic syrup in their stomach is not
good (probably fatal).

/Mats Andersson, Stockholm Sweden