CENLA Bee Club’s Oxalic Acid Field Day

The CENLA Bee Club’s Oxalic Acid Field Day – Held Saturday, March 14

I’d given a talk back in November to the club membership on the various methods used to treat hives with oxalic and formic acids.  From that we programmed a day in March when the membership would get together and make oxalic acid (o.a.) treatment pads using glycerin, o.a. and blue shop towels (one of the methods I’d spoken about).  We began taking orders from the membership and whoever wanted the treated towels at the February meeting and by early March we had orders for something like 600+ towels!

Utilizing videos from You Tube, articles from the internet and Randy Oliver’s website, Scientific Beekeeping.com, I came up with a menu for creating 80 treated towels at a time.  I’m going to present that menu below but it is important to state a few things we discovered during the carrying out of the program.  Understand that this was a Beta Testing Program in which we knew there would be some rough edges that needed adjustment.  Overall, we came out learning a lot and everyone involved worked well together and had a swell time doing it.

Photos of the Event {All photos provided by Stacy Blomquist}

Lessons Learned

  • It was known that the use of a microwave to heat the glycerin and then again heat the glycerin + o. a. mixture would be the funnel that everything had to go through to make a towel. What we discovered was that it took “way too long” to heat the mixtures where the o.a. mixture would be completely dissolved and become clear (not milky).  For one batch mixture it took nearly 20 minutes in a 1250 watt microwave!  Next time we will use a burner to heat things up more quickly!
  • Decide up front whether you’d like to make full-sized towels or ½ sized towels (towellettes – these are towels cut in half).
  • Have an Action and Safety Plan in place and a good location where to hold the event. Ours was in an open bay of a warehouse with lots of room to work, fresh water and electricity available.
  • Order all your supplies and lay out what will be needed days/if not weeks in advance.
  • When taking orders, decide how much to charge/per towel, collect your monies up front and decide how you will package and distribute the treated towels.
  • Should everyone who orders be obligated to attend the field day?  This last point was a no-brainer in that many who ordered couldn’t/didn’t show.  However, the adage “5-10 % of the people of an organization will do 90-100% of the work”, did not apply at our event!  We have 32 paid members in our club and we had 26 people show up to help out.  Of those, 21 were members and five were visiting from other clubs or were friends/spouses.  Everyone helped and actively participated.  We had a blast!
  • We’d originally planned the event would last two hours but it actually took about 3 hours (see number 1 above).
  • NOTE: it was discovered that our recipe for 80 towels actually made 100!(*See Below)

Here then is the Action Plan and Menu we used:

Action Plan

The layout in the bay

  • Paul will be responsible for setting up some sort of signs directing people to the workshop area.
  • I [Tim] will be bring “everything” but the tables and microwave. These items include a weighing scale, volumetric measurement devices, jars, trays, cleaning rags, blue shop towels, glycerin, oxalic acid, stirring rods, 9 ml. Vinyl gloves (box of 50), 5-gallon buckets, tape, plastic to cover the tables, rolls of shop towels cut in half
  • Those responsible for setting up and laying out the tables and materials should show up an hour early. In other words, by 9 a.m.  [These people are the CENLA Board and Tim].
  • Any additional monies to be collected need to be done before the program starts. [Stacy]
  • We should probably start the Oxalic Acid part of the program exactly at 10 a.m. as planned. Late-comers can be filled in whenever during the two hours planned for the program.  The M-C welcoming everyone to the site will/should be    He will be the one to get the ball rolling, not only for the tours but the o.a. portion of the program.
  • There will be an easel describing the recipe to make the treated towels. The procedure for making the towels will be gone over with the attendees prior to their beginning work.  The layout setup will be shown everyone at this time. [Tim]
  • A SAFETY TALK will be necessary before beginning. [Paul and Tim].
    • Each attendee should have been instructed via a group emailing/Facebook announcement that they should/could bring their own safety glasses and work bib – [Stacey to take care of this.]
  • There will be two rows of tables; each row will be comprised of one 8 foot table. These will be covered with plastic (the plastic will be taped below the tables).
  • At an end of each table will be a 2 gallon plastic bucket, several green trays (~4), a paint stirring stick, rags for wiping up (located in a plastic 5-gallon bucket marked “clean rags” a 5-gallon bucket marked “dirty rags” both of which will be on the floor), plastic bags for packaging the completed towellettes and at one table a box of black 9 ml. gloves – to be shared as needed between the tables.
  • Following the program, all the gloves, mixing ware, trays, table top coverings, stirring rods, rags, buckets, weight scale, measuring devices, etc. are to be gathered up (DON”T THROW ANYTHING AWAY – it can all be used again!).

I’m sure there is a lot more we need to do/talk about but this is a beginning.  Your input here before the weeks is out and we are at the hatchery will be welcome.  Take note of your duties and what might need to be done.  Each of us must not take over doing all the “hands on”.  Leave that to the members.  I for one will be more than happy to watch.  Thanks, Tim.


This method of application can be used to apply oxalic acid (o.a.) via absorbent materials repetitively as needed throughout the year.

For making one treated towel ( a towellette is a full-sized towel cut in half)

Materials needed:  blue shop towels, food grade glycerin, o.a., and scale,

protective gloves, zip lock plastic bags and containers for mixing and measuring.

Steps (for creating one application of one towellette):

  1. Measure 25 ml (~31 grams) of glycerin
  2. Microwave the glycerin for 10-15 seconds (keep under 160 degrees Fahrenheit)
  3. Measure 25 grams o.a.
  4. Mix o.a. into glycerin and stir for 2 minutes or until well-mixed.
  5. Reheat mixture for 10 additional seconds (keep under 160 oF). Stir until dissolved.
  6. Place one towel in tray with mixture and stir until saturated.
  7. Squeeze excess solution from towel then weighing, make sure it weighs 31 grams.
  8. Store in zip lock bag in refrigerator until applied in hive on top bars of single brood box or between brood boxes if two are present.
    1. Bees will take 4-6 weeks to remove it – more than enough time to overlap the varroa mite’s life cycle and bring their population titer levels to < 5%. Reapplications can be carried out as needed throughout the seasons.

Recipe for making 583 treated shop towelsx x (1,166 towellettes)


  • A roll of blue shop towels has 55 full-sized towels. Three rolls have (3 x 55 = 165 towels).  Cutting a package of 3 rolls in half will produce 330 towellettes.  Two packages of three rolls each of towels will provide 330 towels or 660 towellettes.
  • We have an order in for 600 towels so 11 rolls will be needed: (600/55 = 10.9 rolls).  A hive can be treated using one towel placed on the top bars of the second brood box or by placing one towellette on the top bars of each of the two brood boxes.  I have cut 6 rolls in half and left another 8 rolls intact.  These can be cut in half on site if desired.  We can discuss with the membership at the get-together.
  • Glycerin
    • 25 ml. per towel = 0.0066 gal. = 0.1 cup
    • One gallon = 4 quarts = 8 pints = 16 cups = 4,000 milliliters
    • ¼ gallon = 1 quart = 2 pints = 4 cups = 1,000 milliliters
    • (1,000ml / 25 ml) = 40
    • Therefore, 1/4 gallon will treat 40 towels (80 towellettes)
  • Oxalic acid
  • 25 grams per towel = 0.06 lb. or 0.9 oz. by weight
  • (40 towels x 0.06 lb.) = 2.4 lbs. of o.a.
  • Mixing 1/2 gallon of glycerin with 4.8 lbs. o.a. will treat 80 towels*[See Above Note – Item #8] (160 towellettes).
  • The CENLA Beekeeping Club has an order in for 600 towels (treatments)
    • We have 35 lbs. of o.a. and 5 gallons of glycerin.
    • Thirty-five lbs. o.a. will provide for 583 treated towelsx x. Five gallons glycerin will provide for 640 treated towels.


  • Because we will be using a microwave with limited space within it to heat the glycerin, we will only heat 2 gallon (8 cups or 2,000 ml of glycerin) at a time. This will allow for the treatment of 80 towels.


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