Thursday, 28 December 2017

Dropping Acid with the Mayor of Bath

Beekeeping is not normally a winter activity, but there are a couple of jobs that do need to be done while the weather is cold, and the hives are quiet.  One of these is making frames.  I know that I will need 32 frames in the spring, to replace the combs in the two hives and the nucleus.  Plus, it would be wise to have 11 spare frames in case of anything unexpected, so that's a total of 43 frames needed.

Total made as of today?  0 frames.  Not going well so far...

I met with Ian this morning (regular readers will know Ian as the Mayor of Bath, and also the owner of my former queen Caroline) and he has already been busy putting together his new hive in preparation for a colony split in the spring.  So Ian is definitely winning the "best organised beekeeper" contest!

Apart from comparing carpentry progress, there was an important reason for Ian and me to meet today.  This was to give a varroa treatment to each of the hives - in this case, oxalic acid.  I'm going to do a more detailed post next month on varroa treatments, but for now the important thing to understand is that oxalic acid is absorbed by varroa mites (usually via the feet) and kills them when it reaches the body.

The method relies on the mites coming into direct contact with the oxalic acid, so any mites that are inside capped brood cells will escape the treatment.  For this reason, the application of oxalic acid works best when there is little or no brood.  And the time of year when bee hives have the least brood is on, or just after, the winter solstice.  This is because brood rearing is (in part) controlled by the length of day, and the shorter the days get, the less the queen will lay - particularly if the weather is cold.  Around the winter solstice (21st December in the northern hemisphere) the days are at their shortest, and brood rearing will be minimal, or stop altogether.  This means that most, or all, of the mites in the colony will be on the bodies of adult bees, where we can attack them.

So, today being a chilly morning and one week after the solstice made it the ideal day for oxalic acid treatment.  Ian came prepared with a mix of oxalic acid dissolved in sugar syrup.  This is then put into a dispenser, which contains a 5ml reservoir.  What you do is squeeze the dispenser to fill the reservoir, and then trickle the acid/syrup mixture onto the bees.  Here's Ian doing just that:

And here's a closer look at the dispenser, showing the reservoir at the top-left:

The best technique involves trickling the mixture along the "seams" - i.e. the gaps between the top of the frames - so that it dribbles down onto the bees getting them nice and sticky.  As the mites walk around on the bodies of the bees, they get the mixture on their feet, and as it dries it forms oxalic acid crystals.  These then get absorbed through the mites' feet, and as the acid re-dissolves in the mites' haemolymph, it kills them.

So, with all of the hives treated for varroa, that's the last beekeeping task of the year done.  I hope you had a great Christmas, and I wish you all a very happy New Year!

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