Waldemar asked:

> So, if a recipe says to use 75g of OA, and one has only the OA dihydrate,
> then, according to the molecular weight ratio, 105g of the dihydrate
> should be used?

My understanding is that oxalic acid is normally available as the dihydrate
and that formulae given for treating varroa are based on it.  I sometimes
use the drip method on colonies returning from the heather moors when is is
to cold for thymol.  The formula I use is 35g oxalic acid dihydrate in 1
litre of 1:1 (sugar:water by weight) sugar syrup and 5ml is applied per seam
of bees.

There is good information here:

http://www.apis.admin.ch/en/krankheiten/oxal.php

Peter Edwards
[log in to unmask]

::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::
-- Visit www.honeybeeworld.com/BEE-L for rules, FAQ and  other info ---
::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::