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Oxalic Acid Dribble Treatment

Prepared by Linda Zahl President Columbia County Oregon Beekeepers

Oxalic Acid Preparation and Dribble Treatment of Honey Bee Colonies

This can also be found in our December 2020 Newletter

  1. Items needed.

    1. Soft or distilled water.

    2. Granulated White Sugar.

    3. Oxalic Acid Crystals = Wood Bleach.

    4. Baking Soda.

    5. Two Mason jars Two plastic containers

    6. Two lids for the jars (one of which must be plastic)

    7. Eye protection h. Eye wash cup

    8. Nitrile or Latex gloves

    9. Particulate filter mask (paper)

    10. Electronic weigh scale

    11. Thermometer

    12. Small piece of paper

    13. plastic spoon

    14. 0.50 ml syringe

  2. ​Notes about Oxalic Acid

    1. The final preparation will be a 3.5% solution which is twice the concentration of naturally occurring Oxalic Acid found in chives, parsley, and rhubarb

    2. Always have a Baking Soda/Water Solution stored in a jar on hand. The jar’s top can be metal or plastic. This is to be an emergency rinse to neutralize the acid in case the Oxalic Acid gets on your skin or eyes. It is always nice to have an eye wash cup also

    3. Crystals must be weighed (not measured) because they clump. Place the small sheet of paper on top of the scale before measuring the crystals

    4. Sugar and Water are the same by weight and by volume: 1 pint granulated sugar = 1 lb and 1 pint water = 1 lb

    5. Never use metal because it will react with the acid. Use glass or plastic

    6. Oxalic Acid will react with hard water and cause a precipitation to occur. This will make a solution of unknown strength. Therefore, it is best to use distilled water

    7. Oxalic Acid Crystals will not hurt you when it is dry but when it comes in contact with mucus membranes (eyes, nose, mouth) or water it is dangerous and will can cause permanent eye damage and severe skin burns. You MUST use eye and hand protection. You should also wear a long sleeved shirt, long pants, socks and shoes. Remember to not rub your eyes or nose while using Oxalic Acid

    8. You will need 5-6 ml of solution per seam of honeybees in the colony. Maximum of 50 ml per colony

    9. Dribble the solution onto the bees. Do not spray. Spraying will have the solution go onto the top bars etc. Practice dribbling the solution with plain water into the sink in order to get used to the syringe and to be able to draw a smooth 5 ml line of water

    10. Use only when brood is absent. It will not control Varroa in capped brood. Remove honey supers in order to prevent contamination of honey

    11. The mixing stage is the most dangerous. Again use eye and skin protection and have the baking soda solution on hand

    12. Oxalic crystals dissolves better in warm water (150 degrees F)

    13. ALWAYS add Oxalic Acid crystals to the water, not water to the Oxalic Acid crystals

    14. Oxalic Acid kills mites for about 4 days. Use a sticky board to count them

    15. The Oxalic Acid solution can be stored in the refrigerator for a week. Always label the jar as POISON. Also add the date it was mixed and that it is 3.5% Oxalic Acid solution

    16. Discard the solution by neutralizing it with baking soda and pouring it down the sink

    17. Wash hands before eating, drinking, chewing gum, using tobacco, or using the toilet

    18. Oxalic Acid treatments can be used to treat Walk Away Splits at 20 days, and newly caught swarms at about day 4

  3. First Aid as stated on packaging- have the product label with you when calling poison control. Oregon Poison Control (1)800-222-1222, Washington Poison Center 1-800-222-1222.

    1. If swallowed; Call a poison control center, sip a glass of water if able to swallow. DO NOT INDUCE VOMITING unless told to by the poison control or doctor. Do not give anything to an unconscious person

    2. If on skin or clothing; Take off contaminated clothing, Rinse skin immediately with plenty of water for 15-20 mins

    3. If inhaled; Move person to fresh air. If not breathing give artificial respiration with a medical device. DO NOT give mouth-to-mouth. Call Poison Control

    4. If in eyes; Hold eye open and rinse slowly and gently with water for 15-20 minutes, remove contact lenses if present after the first 5 minutes, then continue rinsing eye. Call poison control center

  4. First Aid according to Tom Seeley is to have baking soda on hand and use it to neutralize the acid on the skin and in the eyes with an eye wash cup

  5. Prepare the solution

    1. Put on goggles and nitrile or latex gloves

    2. Warm some water to about 150 degrees F

    3. Measure the ingredients. Following are two formulas.

      1. 1 liter water + 1 liter sugar + 35 grams of Oxalic Acid = 1500 ml solution = enough to treat 30 full sized colonies

      2. 86 ml water + 86 grams (ml) sugar + 5 grams Oxalic Acid = 214 ml solution = enough to treat 4 full sized colonies

    4. Put half of the warm water in a glass or plastic jar.

    5. Add the Oxalic Acid Crystals to the water.

    6. Stir until the crystals are fully dissolved.(Don’t shake with a lid on or pressure may build up.)

    7. Add the sugar

    8. Add the rest of the water and stir

    9. Screw on the plastic lid.

  6. Applying the Oxalic Acid Solution as a Dribble to the Hives

  7. Wear goggles and gloves.

    1. Lightly smoke bees down from the top bars.

    2. Fill the syringe with 50 ml Oxalic Acid solution

    3. Hold the syringe about 3-4 inches above the seams at a 45 degree angle

    4. Apply 5-6 ml to each seam that has bees in all the brood chambers and do not exceed 50 ml per hive. Note: what lands on the frame doesn’t count.

    5. Close up the hive.

    6. Count the mite drop in 4 days.



  1. Randy Oliver Oxalic Acid: Questions, Answers, and More Questions: Part 1 of two Parts

  2. “Tools for Varroa Management”

  3. Brushy Mountain Bee Farm Oxalic Acid Dihydrate for Varroa Mite Control on Bees, package directions

How to safely tilt a box up

Tilting up a box in order to look under it without taking it off the hive is one of those bee handling skills that takes a bit of gumption to do with confidence. But it is an extremely useful skill, and well worth learning to do.

Use your hive tool to break the propolis seals all around the perimeter of the box you want to tilt. Stand directly behind the hive and with your hands on the sides of the box, tilt the back end up while simultaneously pulling it towards you about 3 or 4 inches. Pulling it towards you will prevent the box from sliding off the front end as you raise it up high enough to look underneath (or in this case, to apply the oxalic acid mixture.)


When you’re ready to set the box down, don’t just slide it forward. Instead, pick it up, get it level and set it down vertically. Otherwise you risk decapitating a lot of bees along the front edge.


Practice this skill, because you can often gather enough information about what’s going on in a box just by looking at it from both above and below and avoid having to pull frames to inspect them. It’s especially useful during swarm season when you want to check for queen cells without having to pull frames. You can check a dozen hives for swarm cells by tipping the boxes up in the time it would take to check just a few of them if you were pulling all the brood frames, one by one.

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