Drizzling oxalic acid on bees

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.

About Emily Scott

I am a UK beekeeper who has recently moved from London to windswept, wet Cornwall. I first started keeping bees in the Ealing Beekeepers Association’s local apiary in 2008, when I created this blog as a record for myself of my various beekeeping related disasters and - hopefully! - future successes.
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15 Responses to Drizzling oxalic acid on bees

  1. My pink gloves do look good – I almost appear calm while being dive-bombed by fierce bees! Hope we got all the horrible varroa! I remember you telling Else that the oxalic acid treatment is very effective, 90% success rate is very good.


  2. Pingback: Giving the bees oxalic acid | Miss Apis Mellifera

  3. teacher says:

    Reading this has reminded me to get the treatement sorted out for my own hives. I have the Oxalic acid, now I just need to find a recipie for it.


    • Emily Heath says:

      I bought it ready made up so don’t have a recipe sorry. The BBKA has an online advice leaflet at http://www.bbka.org.uk/files/library/oxalic_acid_cleaning_b13_1306864801.pdf.

      This month’s BBKA news has a bit about doing the treatment on p4, they say it’s best to apply within a week of the end of a particularly cold snap, to try and reduce the chances of capped brood being present as much as possible. And you should apply on a warm and sunny day when the bees have broken cluster, so that the acid gets distributed through the nest and onto all the bees.


  4. daveloveless says:

    Any guidance on temperatures? I know I have a much colder winter than you do, but mites already took down one hive. The other hive is very hygienic, so I don’t expect problems with the mites, but still….


  5. svengali says:

    It looks like you are getting a mild winter too. I intend to apply the oxalic acid this weekend but will be doing it via a vaporizer in the entrance. http://www.members.shaw.ca/orioleln/vaporizer.html Hopefully i can get some pics/video and do a post on my blog, I have been negligent in posting lately.


  6. Pingback: Swarming Bees? Bring it! « My Latin Notebook

  7. Pingback: Things I did this winter while waiting for the bees – Part 2 | Tales of an urban bee farmer

  8. Pingback: Oxalic Acid Winter Mite Treatment

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