30. Jan, 2017


This is obtained by dissolving oxalic acid into glycerine, and then saturating a work-shop type paper hand towel with the solution, this creates an extended release application method for the acid into the hive, thus continually killing mites over more than one reproductive cycle, thereby overcoming the limitation of the dribble or vapourisation application methods.

It has been found despite what seems like using fairly large amounts of acid/glycerine mixture, it is not harmful to the hive. Indeed, as best as we can tell, the bees thrive in the slightly acidified environment. But if beekeepers leave oxalic treatments in their hives 365 days a year, or even rely upon it as their only treatment, without rotation of other modes of action, they will be applying strong selective pressure for oxalic-resistant mites, thereby screwing it up for the rest of us.

Method of mixing Oxalic Acid & Glycerine and application etc.

Practical application: OA/gly towels appear to be a dream come true for beekeeper. Please don’t screw up a good thing by overusing them! Rotate treatments—using biotechnical methods, and perhaps Apivar strips etc to delay the development of oxalic-resistant mite.

One would think that it would be easy to simply dilute the OA/gly solution with water to create low-glycerine towels. I’ll save you the trouble— don’t do it - the addition of water causes the OA to come out of solution. There is some interesting chemistry involved that is too complex for this article . The most promising application method was to mix a concentrated solution of OA in glycerine as follows:-

Wearing nitrile gloves and eye protection, measure 25 ml of food-grade glycerine, and heat it to the temperature of hot coffee in the microwave (easiest) or on the stove. Weigh out 25 g of oxalic acid dihydrate ( this can be purchased as a wood bleach), and stir it into the hot glycerin until it is fully dissolved (you can reheat, but don’t bring it to a boil.  This will produce enough solution to saturate ONE work- shop towel (multiply these figures by the number of towels that you wish to prepare). Soak a stack of towels in the warm solution until they are all fully saturated. Then place them in a plastic tray with a drain, and squeeze or press them until you’ve recovered half the solution (it will be surprisingly blue if using a blue towel, and can be reused).

The final “dry” towel will hold about 25 g of solution, and weigh about 31 g.

Allow work-shop towels to soak it up, [ 1 towel per hive] to press the solution out of the towels until only a fraction remains. Press towels with a board on top of the towels. To squeeze out the surplus liquid, for example applying the weight of a 25ltr drum half filled with water is ideal. Remember to bottle the squeezed out liquid for later use.

Always handle the towels with nitrile gloves (as the OA/gly solution sticks readily to your skin, and can easily be transferred to everything and anything you touch!). Luckily, it washes off easily with warm water. I am not suggesting that you actually do this, but it is easy to check for residues on your fingers by seeing if they taste like lemon juice. Oxalic acid can be easily neutralized by baking soda dissolved in water.

Application:-   Lay the OA/Gly towel across the top of the brood area of the frames. The bees will come into contact with the towel collecting the miticide on their exoskeletons. Eventually they will chew up the towel removing the towel bit by bit and it will be observed on the landing board of the hive. It has yet to be confirmed, but perhaps, as the mite moves over a bee carrying oxalic residues on its exoskeleton, the mite absorbs the acid through the thin cuticle of these pads. (Findings by Dr. Dennis van Engelsdorp suggest that acids may also affect the mites’ sensory papillae.)

Article extracted from the excellent research which can be found at:-


Article written by Graham Robinson.