Not a cookery recipe but an anti-varroa treatment commonly used in the UK during December or January whilst the bees are clustering and little or no brood is present. The reason for doing the oxalic acid treatment at this time is that the varroa mites will be at their most vulnerable, overwintering on the adult bees rather than safely hiding in capped brood.
The acid cannot harm mites within capped brood but it will reach mites on the adult bees, giving it an average 90% success rate. The acid is mixed with sugar solution and then quickly drizzled between each frame with bees on. The acid has a corrosive effect on the probosis of the varroa mites, preventing them from sucking the haemolmyph (equivalent of our blood) from the bees. It also damages their respiratory apparatus, causing the little buggers to drop off the bees in droves.
I made a video of Ealing Association member Pat Turner doing a very professional job of administering the acid to his hive:
My favourite bit is when Pat says: “They don’t like it up ’em!”
Emma bravely took on the job of drizzling David’s colony, known as the moodiest in the apiary. I started trying to video this, but the bees became too interested in my hands, which were uncovered to film, so I hastily put my gloves back on. John Chapple had a veil on (unusually for him, oxalic acid time is one of the few occasions on which he wears a veil as the cold weather makes the bees moody) but not gloves, and received a few stings on his hands from David’s ladies. Here’s the very short video, showing off Emma’s stylish pink gloves:
We did our two hives and were pleased to find them both doing well and looking strong. Emma has done a great post on this giving more information on how the treatment works: http://basilandbees.wordpress.com/2012/01/01/giving-the-bees-oxalic-acid.
EDIT: I have since come across this great post on Eastvanbees’ blog, ‘Things I did this winter while waiting for the bees – Part 2′, in which he describes how he treated with oxalic using a vaporiser. This seems like a good alternative way of doing things if you live in a very cold climate or just would rather not open up your hive, as it can be done through the entrance without the roof needing to come off.
He also sent me a link to this great ScientificBeekeeping.com article on Oxalic acid Q&As, which explains in detail how oxalic works, how to apply, when to apply and probably everything there possibly is to know about oxalic, while a second follow-up post deals with how to do the vaporiser method.