Ultimate Guide To Oxalic Acid Vaporization
Instruction Manual for Oxalic Acid Vaporizers
What you need:
- Oxalic Acid (OA) crystals
- Oxalic Acid vaporizer
- Timer
- Measuring spoon for OA crystals
- Respirator mask
- Acid resistant gloves
- Eye protection
- Cloth to block hive entrances
Always wear your mask and other protective items. Breathing the fumes can cause severe irritation and burns to the throat. Avoid contact with the crystals because oxalic acid can cause a burning sensation. Keep a smoker lit at all times and stand up-wind.
Instructions:
- Add 1 gram of oxalic acid per brood box, no matter the brood box size, to the pan of your OA Vaporizer. You can use a 1/4 tsp. as a measuring tool. 1/4 of a tsp. is equal to 1 gram. A colony with 2 brood boxes would need 2 grams (1/2 tsp.) for treatment, and a nuc box would use 1/2 of a gram (1/8 tsp.).
- Insert the vaporizer about 1/2 to 3/4 of the way into the hive from the front entrance.
- Seal any openings in the entrance with cloth or foam.
- Put your respirator on.
- Connect your vaporizer to the power source for 2 - 1/2 minutes.
- Disconnect the vaporizer from the power source.
- Wait for 2 minutes and remove the vaporizer to prepare for the next hive.
- After taking the vaporizer out, reseal the hive for another 10 minutes. If you wish, after disconnecting the vaporizer from the power source, you can leave it in the hive for the full 10 minutes.
- Remove all of the cloth or foam that is sealing the entrance.
- Make sure that the vaporizer is cooled down before using on the next hive or storing the vaporizer. If you have the Varrox model, you can dunk it into water to cool it down. With the Varrocleaner or VarroVap models, wipe out the cup with a wet cloth.
- If you have brood present repeat these steps every 7 days for 3 weeks. A total of 3 treatments are required, as the vapor doesn't kill mites in the capped brood cells, so you need to vaporize those mites as they emerge with the brood during this time frame.
- If you have a brood less period when you treat, then only 1 treatment is required.
Oxalic Acid Vaporization - Questions & Answers
What is Oxalic Acid?
Oxalic acid is an organic compound, it is a colorless crystalline solid that forms a colorless solution in water. In terms of acid strength, it is much stronger than acetic acid. Typically, oxalic acid occurs as a dihydrate.
Where is Oxalic Acid found?
OA is found in peanuts, pecans, wheat bran, spinach, rhubarb, beets, beet greens and chocolate. Some others include soy foods, sweet potatoes, black tea, berries and other dark leafy greens, like Swiss chard and collards. It is what gives food that “bitter” taste.
What happens to Oxalic Acid when heated (vaporized)?
When OA reaches 215 degrees (f) the water boils off leaving anhydrous (water free) OA crystals. At 315 degrees the OA crystals start to sublime (go from a solid to a gas). At 372 degrees, OA which has not sublimed decomposes to form formic acid and carbon monoxide. However, the decomposition of OA to formic and carbon monoxide can only occur under laboratory conditions, not in the apiary.
How does Oxalic Acid kill mites?
OA vapors enter through the soft pads of the mite’s feet and travels to the blood stream thus killing the mite.
Is Oxalic Acid safe for my bees and will it contaminate my comb?
When used as directed, OAV does not harm the queen, bees or the brood! And it does not contaminate the comb as poisons do. There are naturally occurring levels of oxalic acid already found in a hive. While OAV elevates that level, the hive returns to pre-treated levels shortly after treatment. Within days of vaporization, the bees will remove the residual OA crystals from the hive.
How much Oxalic Acid is used in the OAV process?
The recommended dosage is one gram per brood chamber. Most have 2 brood chambers, so use 2 grams. Use the recommended doses only - more is not better!
How is Oxalic Acid heated for use in beehives?
Mostly, a 12 volt, 15 amp vaporizer is used. The OA is placed in the vaporizer’s pan which is then inserted 1/2 to 3/4 the way into the bee hive and connected to the 12 volt battery. When the current is connected to the vaporizer, it heats the pan thus vaporizing the OA.
How long does it take to vaporize Oxalic Acid?
Vaporizers take 2.5 minutes to vaporize OA. The current is disconnected after the time limit and the vaporizer remains in the hive another 2 minutes to finish vaporizing. One should “test fire” their vaporizer prior to using as batteries in various states of age may take longer. Also, if one were to vaporize several hives (using a vaporizer not connected to continuous charger, such as in a running vehicle), vaporization will start to take longer and longer as the battery degrades. Mites will begin to die immediately but you’ll show the largest mite drop the day AFTER treatment.
Do I have to seal the hive when vaporizing?
Yes, although a “perfect” seal is not necessary. During the vaporization period, the hive is sealed and once the vaporizer is removed, the hive resealed for an additional 10 minutes.
Is Oxalic Acid safe for the beekeeper?
Yes, if the beekeeper takes adequate safety precautions. Keep a smoker lit in the beeyard and stand up-wind. DO NOT BREATHE the vapors! The EPA is stating that an acid gas respirator is sufficient, if you use one that filters both vapors and particulates. OA vapors very quickly re-crystallize to cover all the surfaces in the hive making the breathing of the vapors unlikely. However, there is always the chance, so error on the side of safety!
What is the outside temperature range to perform OAV?
You need an outside temperature of 37 degrees f. There is no top temperature. The temperature of 37 f is only needed at time of treatment and 1 - 2 hours thereafter.
Will the mites grow resistance to OA?
Since OA is an acid vs a poison, it is highly doubtful. OA has been used in Europe for 20+ years and there is no reported resistance.
When is the best time to utilize OAV?
The very best time to use OAV is when the hive is brood less. Why? OA only kills phoretic mites -those on the bees, not in the brood. At that time OAV will kill an amazing greater then 95% of the mites in the hive! So when is the hive brood less (or almost so)?
- At the beginning of winter (for many, somewhere between Thanksgiving and Christmas).
- When you've hived a swarm (wait until you see eggs before you vaporize).
- When you've completed a split and removed most of the capped brood.
- When you purchased a package and placed it in a hive (wait until you see eggs before you vaporize).
- If the bees are "flying," the best time to treat is early morning or late evening when most are in the hive.
- With brood breaks. Performing a treatment during this time will kill greater than 95% of the phoretic mites.
Another great time to use OAV is in late August / early September when the mites are out-breeding the bees. What you are doing at that time is killing the mites that are emerging with brood and before they enter another brood cell about to be capped. During this time, you need to vaporize 3 times at 7 day intervals.
If you have high mite loads going into spring you can do a series of treatments before you add your supers; however, other treatments are better suited to treat hives that are heavily rearing brood.
Can I perform OAV with supers in place?
No, you must remove them or place a barrier between the brood nest and the supers. Cardboard or coroplast serve well as a barrier. You can replace the supers or remove the barrier after all the vapors have subsided and new crystals formed. To be safe, wait approximately 15 minutes after you’ve removed all the seals to the hive.
Can you use an extension cord on your OA vaporizer?
Yes, after you’ve made the necessary electrical connections. However, you should use a 12 gauge wire on your extension cord to keep the current from dissipating thus making vaporization take longer. You can also use several vaporizers together for faster treatment of multiple hives.
Is Oxalic Acid legal to use in the US in beehives?
Yes, as of March 10 2015! The EPA approved it for use in bee hives as of that date! The individual states must approve also. You’ll need to check your own state as to status. Many have already approved.
How long will my battery last during OAV?
With a new, fresh battery, you can probably complete at least 20 vaporizations. Your results will vary with your battery, so basically, you won’t know until you have tried!
Can you do OAV from the top of the bee hive?
Yes! Make a 1” or 2” shim (or rim) the same dimensions as the top of your brood chamber. Many beekeeping supply stores sell them already premade! Cut a slot on the bottom of the shim slightly larger than the rod that connects to the vaporizer. To keep the frame tops from scorching, place a small piece of plywood, the size of the vaporizer pan or a little larger, on top of the frames. Fill the vaporizer with the OA, place it on the plywood then place the sim over it all. Make sure you’ve closed off all openings. Replace the top cover, don your respirator, connect the vaporizer to the battery and kill some mites!
Does it make any difference to what battery terminal I connect the vaporizer to during OAV?
No. All that is needed is a completed electrical circuit. Which wire from the vaporizer connected to what terminal on the battery does not matter.
Does Oxalic Acid kill tracheal mites?
It is thought to do so as those who have used OAV have no reported incidences of tracheal mites. However, there are no studies that conclusively prove that OA does so.
Another great use for an Oxalic Acid Vaporizer!
Want to avoid the chore of the sugar roll or alcohol wash to count mites? Or just want to see what phoretic mites are in your hive? Try using your vaporizer. Just vaporize as normal then afterwards insert your sticky board. The drop on the second day will show you about 95% of the phoretic mites you have killed. You can then imagine what’s still in your brood ready to emerge as 80-85% of all mites reside in the brood. You can then decide whether you need to follow up with a treatment regimen.
I have 8 frame hives / I use mediums for brood chambers, how much OA should I use?
You always use 1 gram of OA per brood chamber to vaporize no matter the number of frames or size of the brood chamber. The only exception to this is when vaporizing a nucleus colony (3 - 5 frames), then you use 1/2 gram.
How does Oxalic Acid compare to other Varroa Mite treatments?
After the initial cost of the vaporizer, OA treatments are mere pennies per treatment! With other treatments you could easily spend in one year what the vaporizer costs, and you would need to spend the amount year after year.
