When the shortest day is upon us there is a brief broodless period in the honeybee colony. This is the time conditions are right for oxalic acid treatment. There are two reasons for this:
- When a colony is broodless, all the Varroa are at their most vulnerable out there in the open, either on the bees or creeping about on the comb – Varroa are protected from the effects of oxalic acid when they still inside the cells of the brood nest;
- Oxalic acid can damage open brood so these effects are minimal when there are no or few larvae.
On December 9th 2013 the bees were flying quite strongly and still working the last of the ivy and the Mahonia but there has been little activity since then. Any eggs laid during that spell of mild weather will have hatched by the end of December so that might be the best time to treat.
The following methods can be used during any broodless period, even in the middle of summer, but supers need to be removed. Click here for more about summer oxalic acid treatment. Continue reading Winter Oxalic Acid Varroa Treatment