Reg. Charity No. 510732

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Colin Pavey's Oxalic Acid Treatment advice.

Oxalic acid solution has been used on the Continent and in other parts of the world for many years but has only in the last couple of years has it been widely used as a treatment here.
It is a weak solution (3-4%) which is used, stronger and the bees are at risk, is dribbled onto the bees - about 5ml of soln. per seam of bees. Be quick administering it, do not expose the cluster to the cold for too long. If, in opening the hive, you break the cluster, be quick and close up fast, they'll need to reorganise themselves inside and you don't want them to cool too much. From my own observation, the addition of the solution to the bees makes them active for a short period and this must distribute the treatment round the colony.
Oxalic acid soln. affects (fatally!) the mites which are on the bees, but not those sealed in brood cells. This is why it should be used late Dec,early/mid Jan - when there is no brood. It could also be used on a hived swarm before comb is drawn and egg laying starts.
By late Jan/Feb, when egg laying usually starts, the varroa mites will be diving into the brood cells, pursuing their reproductive cycle, their young feeding on the growing brood. Once this starts, Oxalic treatment a gainst varroa is much less effective - it does not reach the mites.

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