Overview
The extended-release application method is not yet approved by the EPA.
Randy Oliver:
"Beekeepers worldwide are caught between a mite that has proven able to rapidly develop resistance to synthetic miticides, and the slow pace of development and adoption of mite-resistant bee stock - the eventual solution to varroa. During the interim, by choice or lack of alternatives, beekeepers are shifting to the use of “natural” treatments. Oxalic acid (OA) is one of the most promising of those treatments, but its efficacy is limited unless applied during a broodless period. An extended-application method would free it from that limitation.
The problem with oxalic acid is that either of the currently approved application methods (dribble or vaporization) kills mites for only about three days. So unless applied during a broodless period, or repeated at 4-day intervals, oxalic is not very effective over much of the season, due to a proportion of the mites being protected in the sealed brood. By creating an extended-release formulation, we may have found a treatment that is “natural,” suitable for organic approval, safe for the applicator, non-contaminating of honey, shows no noticeable adverse effects upon the colony, as well as being inexpensive and highly effective at reducing mite populations."
We will refer Extended-Release Oxalic Acid treatment as OAE.
References
Please read the following references for more details on this treatment technique.
The following links are from Scientific Beekeeping, a website published by Randy Oliver. Randy Oliver is a world-renowned speaker, educator, bee biologist, leading researcher, commercial beekeeper, and regular contributor to the American Beekeeping Journal. He is one of the premier beekeeping speakers in the U.S. and the owner/author of http://scientificbeekeeping.com.
- Randy Oliver's Latest Work November 9 2021 - a NY Bee Wellness webinar - good comparison of various treatments
- 2022 Extended-Release Oxalic Acid Update - part 1
- Extended-Release Oxalic Acid Progress Report #5 – 2019
- Mite Control While Honey is on the Hive: Part 4
- Mite Control While Honey is on the Hive: Part 2 - good comparison of various treatments
Shopping List
OAE is a very inexpensive treatment, but you need some gear to safely and accurately make it. Here's what has worked well for me:
Equipment
Item |
Name |
Description |
Purchase (price as of May 2022) |
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Induction Cooktop | Provides a safe, no-flame way to heat up the solution. The cooktop surface does not get very hot during use, as the heat is induced directly into the pan. One less thing to worry about. | Amazon
$62 |
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Digital Kitchen Scale | To weigh the Oxalic Acid and Glycerin | Amazon
$28 |
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Pan 1/3 6" deep | To make a double boiler to heat and mix the OA solution. | Amazon
$20 |
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Pan 1/3 4" deep | To make a double boiler to heat and mix the OA solution. | Amazon
$13 |
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Kitchen Tongs | Mixing the solution and bathing the dishcloths. | Amazon
$13 |
Supplies
Item |
Name |
Description |
Purchase (price as of May 2022) |
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Oxalic Acid | The key ingredient. Handle with care - OA is toxic and very acidic. Always wear gloves, eye protection, and a mask. | Amazon
$15 Provides 22 40g doses |
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Vegetable glycerin | Used to dissolve the OA and adhere to the pads.
Best measured by weight. 40g is approximately 33ml. |
Amazon
$10 Provides approx. 28 doses |
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Swedish dishcloths. | These are soaked in the OAE solution and placed in the hive. | Amazon
$20 Provides 10 doses |
Startup cost (equipment and one set of supplies): $166
Treatment cost per hive (one saturated Dishcloth, with 40g OA): $3.04
How To Prepare
Recipe
Per hive:
- 1 Swedish Dishcloth
- 40g Glycerin
- 40g Oxalic Acid
Prep
Usage
Place two half pads (one full Swedish Dishcloth) on the top bars of the lower brood chamber in the spring. They can remain in the hive until the fall.