Beekeeping Information Centre

Oxalic Acid

Oxalic acid is a a naturally occurring organic acid normally found at very low levels in honey. It is used to control varroa mites on adult bees. The acid works by contact with varroa mites on adult bees, preventing them from sucking hemolymph. It does not penetrate capped brood, and may kill open brood, so must only be used in winter when the colony is broodless.

Approved oxalic acid treatments in the UK at the time of writing are Api-Bioxal, Oxuvar and VarroMed. Bees are classed as food-producing animals and as such beekeepers are required to keep an up to date record of all veterinary medicines applied. There is a suggested record sheet as part of the Bee Craft Apiary Guide to Record Keeping, which is available from the Bee Craft Shop. One can also be downloaded from Bee Base here.

To check if a product is licenced for use in the UK check the Veterinary Medicines Directorate Product Information Database.
Use the product search facility to find a specific product or to select the species bees.

Oxalic Acid Trickling to kill Varroa MitesWinter debris on varroa monitoring tray

Margaret Cowley

In the depth of winter the queen often stops laying eggs. This means there is a period of up to about a month around New Year when there is no brood (larvae) in the hive. We can take advantage of this to kill a high percentage of varroa mites, using oxalic acid solution, as they are all on the adults, not hiding away in cells sucking the blood of larvae as they are at other times of the year. Oxalic acid solution should not be used when there is brood present as it can cause larvae to be removed. The treatment can be so effective that it need only be used once a year.

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WATCH THE VIDEO

Since this video was made various oxalic acid products have been approved for use in the UK. The method of trickle application shown in the video is still the same.

OXALIC ACID TRICKLING by Bee Craft Deputy Editor – Margaret Cowley

The trickle treatment with oxalic acid against varroa in honey bees

Only approved oxalic acid products should be used. To check if a product is licenced for use in the UK check the Veterinary Medicines Directorate Product Information Database.

 

This is the video tutorial from Chemicals Laif, manufacturers of Api-Bioxal.

 

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Wally Shaw writes about oxalic acid in Bee Craft, December 2010:

 

 

Recommended reading:

 

Advisory leaflet from the National Bee Unit

Best Practice Guideline No. 11 – Varroa available to download.

Healthy Bees are Happy Bees by Pam Gregory NDB

Healthy-Bees-are-Happy-Bees-1Pam Gregory succeeds in making bee diseases interesting and presents the beekeeper with valuable knowledge to enable him or her to improve the health of their colonies. The book not only describes how to recognise disease and what the beekeeper can do to prevent and treat, it also gives background that is invaluable to the beekeeper in understanding the diseases and conditions that may arise, helping to prevent them and judging when and how to treat.

This book is available from the Bee Craft Shop