# Oxalic acid use in Summer (August)



## snl (Nov 20, 2009)

Hi Jim,
Below is a long thread that will answer your questions. But this is a great time to treat as the mites are out-breeding the bees. OA does not harm brood, bees or the queen! 

http://www.beesource.com/forums/showthread.php?307844-Oxalic-Acid-Vaporization-Questions-and-Answers


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## snl (Nov 20, 2009)

Perhaps this will help as well:
Oxalic Acid Vaporization – Questions and Answers:

What is Oxalic Acid?
Specifically: Oxalic acid is an organic compound with the formula H[SUB]2[/SUB]C[SUB]2[/SUB]O[SUB]4[/SUB]. 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 (containing 2 molecules of water) with the formula H[SUB]2[/SUB]C[SUB]2[/SUB]O[SUB]4[/SUB]·2H[SUB]2[/SUB]O.

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?
The jury is still out. It is thought that OA vapors enter through the soft pads of the mite’s feet and travels to the blood stream, killing the mite. It is also thought that it destroys parts of the mite’s mouth. However it works, it decimates mites.

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 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 two brood chambers, so use two grams (which is very close to ½ a teaspoonful. You could use a ½ teaspoon measure in lieu of two one gram (¼ teaspoons). 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 ½ way to ¾ into the beehive and connected to the battery. When the current is connected to the vaporizer, it heats the pan thus vaporizing the OA.

How long does it take to vaporize OA?
Vaporizers take 2.5 minutes to vaporize OA. The current is disconnected after the time limit and the vaporizer remains in the hive another two 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 is 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, use a model 6211 which filters both vapors and particulates. In Europe a mask with an N95 particulate rating is the standard. 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, error on the side of safety!

What is the outside temperature range to perform OAV?
You need an outside temperature of 37 (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, 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 broodless. Why? OA only kills phoretic mites - those on the bees, not in the brood. At that time OAV will kill an amazing greater than 95% of the mites in the hive! So when is the hive broodless or almost so? 
1. At the beginning of winter (for many, somewhere between Thanksgiving and Christmas).
2. When you’ve hived a swarm. (wait till you see eggs before you vaporize).
3. When you’ve completed a split and removed most of the capped brood.
4. When you purchased a package and placed it in a hive (wait till you see eggs before you vaporize.)
5. If the bees are “flying,” the best time to treat is early morning or late evening when most are in the hive.

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 5 day intervals. 
If you have high mite loads going into spring your 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[SUP]th[/SUP] 2015! The EPA approved it for use in beehives 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, I’ve completed 20 vaporizations. Your results will vary with your battery. Basically, you won’t know until you tried.

Can you do OAV from the top of the hive? OR my bottom hive opening isn’t large enough for the vaporizer to enter.
Yes! Make a one or two inch “shim or rim” the same dimensions as your brood chamber. Cut a slot on the bottom of the shim/rim slightly larger than the rod that connects to the vaporizer. 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 rim/shim over it all. Make sure you’ve closed off all openings. Replace the top cover, connect the vaporizer to the battery, don your respirator and kill some mites! 

Does it make any difference to what battery terminal I connect the vaporizer battery during OAV?
No. All that is needed is a completed electrical circuit. Which wire from the vaporizer connected to what terminal on the battery is of no consequence. 

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 of an OA 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 follow up with a treatment regimen. 

I have 8 frame hives or use mediums for brood chambers, how much OA should I use?
You always use one 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, and then it is ½ gram. 

How does OA compare to other 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 do so year after year.


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## enjambres (Jun 30, 2013)

Larry,

You wrote:



> Replace the top cover, connect the vaporizer to the battery, don your respirator and kill some mites!


Nope! Replace the top, *DON YOUR RESPIRATOR*, and only then, connect the battery and off the mites.

Never begin the sublimation until all your presonal protective gear is in place, and checked for seal. Then, you're good to go.

Enj.


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## snl (Nov 20, 2009)

enjambres said:


> Never begin the sublimation until all your personal protective gear is in place, and checked for seal. Then, you're good to go.
> 
> Enj.


But of course you're right Nancy, I stand corrected!


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## philip.devos (Aug 10, 2013)

@ enj and snl: What respirator and cartridge do you either use or recommend?


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## snl (Nov 20, 2009)

philip.devos said:


> @ enj and snl: What respirator and cartridge do you either use or recommend?


Here's one............
http://store.sassafety.com/bandit-ov-n95-disposable-respirator.html


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## wild-b (Apr 23, 2014)

can't you just use the cotton N95 filters at walmart @4 for ten bucks. Menards has them also.


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## snl (Nov 20, 2009)

wild-b said:


> can't you just use the cotton N95 filters at walmart @4 for ten bucks. Menards has them also.


You can but they are not recommended by the EPA for use with OAV. Better safe than sorry. One breath of OA vapers will have you wishing you spent the money.


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## snl (Nov 20, 2009)

philip.devos said:


> @ enj and snl: What respirator and cartridge do you either use or recommend?


Here's another:

http://www.amazon.com/3M-5203-Acid-Respirator-cart/dp/B002D8WGIG

And another...

http://www.amazon.com/3M-Organic-Re...sim_121_4?ie=UTF8&refRID=1RYQ07CFTSB8NYHWEGZP

Larry


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## philip.devos (Aug 10, 2013)

@snl: Thanks for responding regarding the respirators.


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## Thershey (Mar 12, 2014)

I think it's time to quit running the gauntlet, I always get a little whiff while loading or unloading the tool from the neighboring hive. How long do the cartridges last, is it something we should replace after each use or is it a once a year deal?


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## beegineer (Jul 5, 2011)

Well done Snl , sounds do able thanks for taking the time to post thats great info for us not so experienced and to jmfcree for asking the question


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## jfmcree (Mar 10, 2014)

My OxaVap vaporizer, respirator and other safety gear and oxalic acid arrived today. I read the instructions and have what is probably a very basic question, but it isn't clear or I missed it in the instructions.

I am assuming the vaporizer is vaporizing a liquid, but the instructions reference having oxalic crystals and my oxalic acid is a white powder-like substance. I have not opened it yet. Do I need to mix the solid oxalic acid crystals with something before putting it into the vaporizer or does the vaporizer work with the solid crystals just dropped into the pan?

thanks, Jim.


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## emrude (Mar 23, 2015)

You put the powder in the vaporizer.


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## snl (Nov 20, 2009)

jfmcree said:


> My OxaVap vaporizer, respirator and other safety gear and oxalic acid arrived today. I read the instructions and have what is probably a very basic question, but it isn't clear or I missed it in the instructions.
> 
> I am assuming the vaporizer is vaporizing a liquid, but the instructions reference having oxalic crystals and my oxalic acid is a white powder-like substance. I have not opened it yet. Do I need to mix the solid oxalic acid crystals with something before putting it into the vaporizer or does the vaporizer work with the solid crystals just dropped into the pan?
> 
> thanks, Jim.


As stated below, you put the OA crystals in the vaporizer (no mixing with anything). One gram (1/4 teaspoon) per brood chamber. As most have two brood chambers, you'd use 1/2 a teaspoonful.

Get ready to vap some mites!


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## enjambres (Jun 30, 2013)

Please don't use the N95 masks for OA _Vaproization_. Get a proper one. 

You may never need the protection the mask gives you, but the one time when something goes slightly amiss, nothing less than the acid-gas mask will keep you safe. And nobody but a fool believes there will never be any problems.

These are your one and only set of lungs - not exactly trivial organs. Life without healthy lungs is not an attractive prospect. 

Don't push your luck: get a good mask, and still work just as carefully as if you weren't wearing one.

Enj.


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## jcolon (Sep 12, 2014)

enjambres said:


> Please don't use the N95 masks for OA _Vaproization_. Get a proper one.
> 
> You may never need the protection the mask gives you, but the one time when something goes slightly amiss, nothing less than the acid-gas mask will keep you safe. And nobody but a fool believes there will never be any problems.
> 
> ...


Indeed. It needs to be rated for acid gas.


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## snl (Nov 20, 2009)

jcolon said:


> Indeed. It needs to be rated for acid gas.


See some vaporizers below that fit the bill..........


http://www.amazon.com/3M-5203-Acid-R.../dp/B002D8WGIG

And another...

http://www.amazon.com/3M-Organic-Res...CFTSB8NYHWEGZP


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## beepro (Dec 31, 2012)

Jim, the white powder-like substance will turn into a vapor (oxalis gas) when they are heated by the vaporizer. So no need to mix the solid white powder with anything else. Just put the white powder into the vaporizer pan and connect away. Use the proper protection and I am sure you can hold a breath until you can get to open air just in case. Leave yourself an exit!


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## Eyeshooter (Mar 8, 2008)

It's great to protect your lungs but your eyes are are perfect portal for the vapors as well! I use a full face mask with organic acid air filters. 
Here is a link on Amazon:
Mask:
http://www.amazon.com/dp/B007JZ1LG6/ref=rr_xsim_1_1?ie=UTF8&qid=1439734079&sr=0

Air filters:
http://www.amazon.com/3M-Organic-Ca...im_328_10?ie=UTF8&refRID=0RJ6S2CPHTX6KPVZDKXP

Yes, they are more expensive than just a standard respirator but I value my eyes more than the extra $125.

I bought my vaporizer last year from SNL. Works great! Tho' it's been a hard year for me to work my bees and maintain our blog having had rotator cuff surgery, the LOML just helped me do our first 2015 OAV treatment this week. Lots -o- dead mites!

Here is a post I made last year after the first round of OAV treatments if you are interested. It's post 104...

http://www.beesource.com/forums/showthread.php?304050-TF-until-today/page6

Cheers,
John


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