# Considering switching to Oxalic Acid



## Specialkayme (Sep 4, 2005)

Like many, I've tried alot of varroa treatments. While I've heard others say how impressed they were with the various treatments, I can't say I'm ever really impressed. I used Apistan about 10 years ago, before I knew the mites were building up resistance to it and it left horrible residues inside the hive. I've recently used Apiguard, and still had hives die from mites (very temperature sensitive), and I've had other hives abscond while it was in there. Last year and this spring I've used MAQS, but it was very rough on the hives (lost 30% of queens, and most hives that I didn't lose the queens on stopped laying for 3 weeks, plus some brood kill, makes for a HORRIBLE spring treatment option). Can't get Hopguard in my state. Next week I'm going to try Apivar for the first time. We'll see how it goes. I've heard good things about it, but at between $5-7 a hive, per treatment, I'm not thrilled about it.

So I've been looking into OA treatment. I'm not interested in dribbling, as reading Randy Oliver's articles he explains how tough that is on the bees kidneys. I'm also not interested in making a pipe and using a blowtorch. Not interested in being that close to vaporizing OA, and if you don't get the temp right the OA will flash into Formic and Carbon Monoxide (defeats the purpose). So looks like I'd have to get one of those pre-made vaporizers (Heilyser's for $100, for example).

I'm weighing the pro's and cons, and wanted to see if anyone had some input for me that might be helpful.

Pros:
1. It's cheap to treat (runs, based on my math, about $0.25 per hive per treatment)
2. I've heard very little, if any residue left in the hive
3. I've heard it isn't stressful on bees (no queen loss, no loss of brood, no shutdown period)
4. You can treat without opening the hive
5. From videos I've seen, treating is easy
6. Difficult to overdose (not so much with MAQS or Thymol)
7. When you run out, you can just go to the hardware store (no need to pre-order, have it shipped in, worry about the bee store being "out of stock" as everyone and their cousin is treating this month)
8. Not temp. sensitive (can treat in spring, summer, fall, winter, day, night)
9. I haven't really heard of many people switching to OA and then deciding it wasn't a good choice

Cons:
1. Heavy upfront cost. ($100 entrance fee just to see if it works, plus the cost of the battery and the wood bleach)
2. Multiple treatments (like 3 or 4), each one week apart, are needed, making more labor and travel costs
3. Only kills foretic mites (none under cappings)
4. Takes 60 seconds to treat, plus 2-10 min to cool down/circulate per hive (treating a yard of 25 hives would take 1.5 to 4.5 hours)
5. (Kinda a big one for me) It's illegal (really don't want to get in trouble by state inspector, EPA, ect)
6. Make sure you keep your respirator close by
7. PR issues (not a big concern, but doesn't look great to neighbors/bystanders when I pour wood bleach into a pan, jam a metal rod into the hive and hook it up to a car battery)

Anything else I'm forgetting? Input?


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## David LaFerney (Jan 14, 2009)

I use OAV during the late fall broodless period, and - although i haven't done it yet - would use it for a knockdown treatment if ever needed, but I don't think it is a very good regular treatment option option when substantial brood is present. I use apiguard in mid summer, and the combination works for me. So far. 

In cases of hive loss during the summer apiguard treatment - I think that other stresses are as much of a factor as the treatment, and I may be better off to go ahead and lose those compromised hives now while replacement options are still available. Strong hives don't seem to suffer much.

Part of my strategy is that I have more hives right now then I intend on going into winter with.


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## crofter (May 5, 2011)

25 cents or less per treatment, yes. You dont have to leave the evaporator in; part your blocking rags in the middle and slid it out as soon as boil of is finished and push the rags together. Cool with a damp rag, load up, plug in the next hive. I think you could easily get it down to 3 minutes per hive. The cost of any of the evaporator is very quickly paid for the saving on patent treatment strips and transportation.

As for making your own I would not generally recommend it as the sizing of the pan and the amount of glow plug heat are important to get up to temperature in reasonable time without boilover or excessive end temperatures.


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## WWW (Feb 6, 2011)

Looks like you have hit the main points of OAV treatment, now it's just a matter of deciding on your part about whether to pay the entrance fee or not, I for one am glad I did. From this time forward I have opted to do my treatments during August, this is the time frame when my supers are empty and I can either slip a piece of aluminum sheet metal under them to keep the OAV out of the supers or remove them from the hives until after treatments of the brood nest is finished. 

As far as it being illegal I can nether deny nor confirm this, there is a lot of opinions one way and the other on this subject and this thread could very well light another bon fire debate however this one thing I can assure you and that is OAV saved my hives and I am happy to use it .


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## snl (Nov 20, 2009)

Some may argue that it kills beneficial microbes in the hive. That is most likely true, but they must quickly rebound as evidenced by the renewed vigor of an infested hive after use. 
You should test for mites in August as the mite population explodes during this time. Me, I see mites in drone brood, I treat.........


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## Specialkayme (Sep 4, 2005)

David LaFerney said:


> In cases of hive loss during the summer apiguard treatment - I think that other stresses are as much of a factor as the treatment, and I may be better off to go ahead and lose those compromised hives now while replacement options are still available. Strong hives don't seem to suffer much.


I can't say I've seen the same. I've seen strong, and weak hives collapse after apiguard treatment. I don't know that apiguard is the single, or even if it is a contributing factor. Just an observation. I'd also say it didn't do much to knock down the mite counts (or as much as I had hoped). If I treat in August, I've noticed I might have mite issues in October. Not really what I'm looking for. I like apiguard better than MAQS, but I don't think it's the answer for me. 



crofter said:


> I think you could easily get it down to 3 minutes per hive.


Still, for a 25 hive apiary, you are looking at an hour and a half minimum. Those yards that have 50 hives, three hours. Then keep in mind you have to repeat next week, for three consecutive weeks, to really be effective. In a 25 hive yard that's a total of around 4.5 hours to treat, and in a 50 hive yard that's a total of 9 hours to treat, per yard. I'm not saying that's horrible. But the MAQS, Apiguard, and Apivar all go on in one application, and can be installed in seconds (literally).



crofter said:


> As for making your own I would not generally recommend it as the sizing of the pan and the amount of glow plug heat are important to get up to temperature in reasonable time without boilover or excessive end temperatures.


I wouldn't consider making my own. For the work put into testing it out, $100 is worth it to me. 



snl said:


> You should test for mites in August as the mite population explodes during this time. Me, I see mites in drone brood, I treat.........


Treatments aren't the only piece to my varroa puzzle. Testing (which my sugar shakes aren't a great indicator, but it helps) and using varroa resistant stock are also part of it, but you've got to treat at some point. Just making sure you do it at the right time (not too late, and not when the hive doesn't need it).


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## crofter (May 5, 2011)

I havent done more than 8 hives at once and only single treatment required. Most people with more hives would likely have more than a few evaporators. If you wore a respirator and worked with a fairly warm evaporator (the actual burn off time is only a bit over a minute) the time could be cut way down; the three minutes would be a careful no rush rate. My son uses pieces of the foam water pipe insulation to pop in for closing off. It is cheap and quick and easier than fussing with rags if you have full length bottom opening. 

I have seen posts where people have worked out a system that can make the application to multiple hives a lot quicker than we are kicking around here. I have not been motivated to save time because I waste a fair bit of it playing with the bees anyway. One plus with OA is that it keeps virtually forever without having to refrigerate etc.


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## camero7 (Sep 21, 2009)

> Still, for a 25 hive apiary, you are looking at an hour and a half minimum. Those yards that have 50 hives, three hours.


i use 2 vaporizers when treating my yards. I spend less than 2 minutes per hive. I don't block the entrance or bother with sealing the hive. I put one in a hive, load the other one, by that time the first is done and I pull it out, dip it partially in water, load it, pull the other one and so on. I use a battery pack with clips to hook it up to the power so I'm not wasting time. My yards are all around 25 hives and I'm in and out in about 45 minutes total if all I'm doing is treating. I like not having to lift or fight the bees. I do almost all of my vaporization with just a veil. I've never bothered with a mask, just know which way the wind is blowing. A little whiff will make you cough a little but it's over quickly. BTW- I've been getting a very good mite kill with 3-4 treatments.


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## cg3 (Jan 16, 2011)

I just started this year's treatments. I treat about a dozen here at home and half dozen or so at an outyard. It takes a little over an hour here and 45 minutes there. Cost for the Oxalic is more like 10¢ per. I do it 4x. Bees are noticeably zippier afterward. Can hardly find a mite going into winter. I'm sold.


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## rwurster (Oct 30, 2010)

I occasionally hit a hive with OA if they have a mite load and are suffering from it. You can vaporize with honey supers on (I don't). If it has to be done I do it about this time of year if honey supers are off and do 2 more treatments 1 week apart. It does kill mites and I have noticed that if a hive was 'treated' the following spring there is almost no sign of nosema. Start with your necessities: Safety equipment - A respirator with an organic acid filter (forgot which color code it has).

You can also vaporize with a pipe and a torch for cheap if you just want to try it out. I drilled a hole in a quilt box and put a piece of plexi over it, works great and you can see the bees fanning the vapor around the hive (heated pipe method). I don't bother buttoning up the hive when I do it either. My 'wood bleach' is 100% OA.

My honest opinion is to get your respirator, make or buy your vaporizer, try to get 100% OA, and knock yourself out. You just saved lots of $$$ 
And always, common sense. Buy your respirator first  :thumbsup:


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## snl (Nov 20, 2009)

rwurster said:


> My honest opinion is to get your respirator, make or buy your vaporizer, try to get 100% OA, and knock yourself out. You just saved lots of $$$ And always, common sense. Buy your respirator first  :thumbsup:


I could not agree with you more, a respirator with an N95 rating works just fine.......... you can find them at Walmart, Ebay & Amazon


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## snl (Nov 20, 2009)

cg3 said:


> Cost for the Oxalic is more like 10¢ per. I do it 4x. Bees are noticeably zippier afterward. Can hardly find a mite going into winter. I'm sold.


10 cents per treatment, zippier bees and barely no mites........ no harm to brood, bees or the queen.......can't beat that!


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## Jeffzhear (Dec 2, 2006)

Specialkayme said:


> "... as reading Randy Oliver's articles he explains how tough that is on the bees kidneys....


Just curious, it is tough on bees kidneys? I am thinking Randy's articles (which I have not read) may be referring to human kidneys and that OA is tough on them. FYI, regarding honey bees, according to http://www.cyberbee.net/biology/ch3/ "Malpighian tubules are small strands of tubes attached near the end of ventriculus and functions as the kidney, it removes the nitrigen waste (in the form of uric acid, not as urea as in humans) from the hemolymph and the uric acid forms crystals and is mixed with other solid wastes."


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## Belewsboy (Jun 6, 2012)

I used to treat with formic acid on a fume board. Results were always good until I lost a queen...maybe from the formic. So I bought the Varrox vaporizer last year. Very easy, quick and really knocked the mites back. Only treated once in November of last year and haven't treated since. Will sample in a week or two and treat if necessary. I think its the way to go. Specialkayme...you are only a few miles from me...you are welcome to try my Varrox when the time comes.


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## McBee7 (Dec 25, 2013)

ordered my vaporizor this week, I intend to try it on some packages that I installed this spring that I suspect need it badly.....I know I need to test ..... I also have some summer started nucs that have a proven track record of treatment so I'm thinking that apivar may work for them but will see.I will test them..... The advise given to me is that " healthy (mite free) bees will overwinter MORE succesfully than any-o-package bees ....even if it costs me $20 or more to treat bees that survive to spring its cheap when compared to $100 packages or nucs....

==McBee7==


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## ABruce (Dec 27, 2013)

I am a new beekeeper this year, and have seven hives, After lots of reading I bought the vaporizer and the oxalic acid. One question I have not seen answered, unlike many other treatment options the OAV dissipates quickly. How does one ensure they get most of the field bees? Do they not have mites riding around on them waiting to come back and infest the colony all over again? Do you do the treatment later in the evening or very early in the morning to maximize the effect?
thanks


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## John Scifres (Mar 25, 2014)

An N95 respirator is for particulates only. Read the MSDS for the product and decide which respirator to use. The ones I have read recommend organic vapor cartridges with a dust/mist filter. Oxalic acid has a low permissible exposure limit which indicates high hazards.


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## Harley Craig (Sep 18, 2012)

I have started experiementing on one of my hives with this I use a homemade copper job and a torch which works great for one hive, the problem with them is not the acid getting too hot and converting as that can't happen in an open vessellit will just boil off at its boiling point, the problem would be if you plan to treat multiple hives in a yard it takes some time for them to cool enough to open up and reload with chemical. If I ever decide to start treating all hives with it, I would purchase an elec open pan model.....then again I could build probably 10 of the copper ones for the price of the commercialy sold elec ones, and even more if I just used a length of copper pipe with a curve and one end smashed flat.


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## Gypsi (Mar 27, 2011)

If I have to treat this year, OA sounds worth the effort.


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## Stephenpbird (May 22, 2011)

Harley Craig said:


> If I ever decide to start treating all hives with it, I would purchase an elec open pan model.....then again I could build probably 10 of the copper ones for the price of the commercialy sold elec ones, and even more if I just used a length of copper pipe with a curve and one end smashed flat.


I talked to a German guy who swears by one of those aromatherapy vaporizers, the ones that use a small candle. He puts an empty super on the hive, measures out the dose of OA into the vaporizers pan, places it on the top bars. Lights the candle and puts it into the vaporizer. Closes the hive and comes back in 10 minutes or more. You can't get cheaper than that. 
Yes, I am being serious.


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## CBoggs (Jun 20, 2014)

That is an excellent question, I also have been wondering the same thing. Can someone answer?


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## hammer (Aug 18, 2014)

camero7 said:


> i use 2 vaporizers when treating my yards. I spend less than 2 minutes per hive. I don't block the entrance or bother with sealing the hive. I put one in a hive, load the other one, by that time the first is done and I pull it out, dip it partially in water, load it, pull the other one and so on. I use a battery pack with clips to hook it up to the power so I'm not wasting time. My yards are all around 25 hives and I'm in and out in about 45 minutes total if all I'm doing is treating. I like not having to lift or fight the bees. I do almost all of my vaporization with just a veil. I've never bothered with a mask, just know which way the wind is blowing. A little whiff will make you cough a little but it's over quickly. BTW- I've been getting a very good mite kill with 3-4 treatments.


if your method works that's a big time saver. from what I been reading its 2.5 min to vaporize and another 10 min with the hive sealed up. I was reading somewhere that the tractor/lawn mower battery is to small and can only do 20 hives. have anyone tried to parallel the batteries? 2 tractor batteries? 

my concern is my bees are on 6 way pallets with screened bottom boards and I would have to seal off the bottom ! correct? if I use the corrugated plastic political signs to seal them I am afraid that the vaporizer would be to thick to slide in!


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## snl (Nov 20, 2009)

hammer said:


> if your method works that's a big time saver. from what I been reading its 2.5 min to vaporize and another 10 min with the hive sealed up. I was reading somewhere that the tractor/lawn mower battery is to small and can only do 20 hives. have anyone tried to parallel the batteries? 2 tractor batteries?
> 
> my concern is my bees are on 6 way pallets with screened bottom boards and I would have to seal off the bottom ! correct? if I use the corrugated plastic political signs to seal them I am afraid that the vaporizer would be to thick to slide in!


Previous post........I use an old radio flyer wagon to carry two car batteries wired in parallel to each other which in turn is wired to a 100 watt solar panel (charge controller) and vaporizer(s). Mobility was my biggest issue and this set up easily gases 24 hives quickly. A commercial guy was interested in my setup/start up cost/cost per hive, so I invited him for a look-see. Pretty sure he's running similar set ups in his yards this year with 2 smaller panels, but using heavier wagons with pneumatic tires.

No one is forgetting their respirator I hope.

On the ScBB, insert the vaporizer in on one side of the hive and use coroplast on the rest........ that little opening won't affect the treatment as most of the vapors rise.


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## Gypsi (Mar 27, 2011)

Stephenpbird said:


> I talked to a German guy who swears by one of those aromatherapy vaporizers, the ones that use a small candle. He puts an empty super on the hive, measures out the dose of OA into the vaporizers pan, places it on the top bars. Lights the candle and puts it into the vaporizer. Closes the hive and comes back in 10 minutes or more. You can't get cheaper than that.
> Yes, I am being serious.


I only have 2 hives, I think that one might be in my budget


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## CBoggs (Jun 20, 2014)

Hey All, is there only one type of Oxalic Acid, or is there a specific type that is recommended? Thanks for the info,


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## snl (Nov 20, 2009)

Only one type but it has different percentages of purity. You'd like to 
get the highest possible. Something above 95% is good. Available on EBay, Amazon 
and Ace hardware.


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## Harley Craig (Sep 18, 2012)

Stephenpbird said:


> I talked to a German guy who swears by one of those aromatherapy vaporizers, the ones that use a small candle. He puts an empty super on the hive, measures out the dose of OA into the vaporizers pan, places it on the top bars. Lights the candle and puts it into the vaporizer. Closes the hive and comes back in 10 minutes or more. You can't get cheaper than that.
> Yes, I am being serious.


not familiar with them but I can't imagine them being cheaper than a 6 in piece of 1/2 copper line with one end hammered flat to seal it. Lol


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## Redbug (Feb 8, 2014)

Just a comment or two...

I have just recently gotten a vaporizer to do 9 hives. After the first treatment and seeing how slow I was...I gave it some thought. Then I went to Walmart and bought four of the cheapie digital timers for about $4.50 apiece, (kitchen section). Using several timers at once...improved efficiency greatly. One timer is kept set at around 3 minutes for the burnoff time, and the other three timers are set for around 10 minutes. Using these several timers, you can just bump along hive to hive, with the 10 minute timers alarming when they are done...as you move along down the line. The secret to being efficient time-wise is to keep the vaporizer smoking with little lag time between hives. You can be two or three hives ahead of the last 10 minute timer counting down if you are fast enough. 

My second comment...mentioned to me by a good friend...about using oxalic acid and not approved in this country. I am not selling any honey...I am just raising bees and expanding my apairy. It does not affect anyone but me and my bees.


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## scituatema (Aug 30, 2014)

Search on youtube this "Sublimatore ad aria"
It is in english but they use heat gun and it looks very fast.
any ideas ? How can we make the same one ?


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## snl (Nov 20, 2009)

Specialkayme said:


> I'm weighing the pro's and cons, and wanted to see if anyone had some input for me that might be helpful.Anything else I'm forgetting? Input?


Pros:
1. It's cheap to treat (runs, based on my math, about $0.25 per hive per treatment)
Answer: Probably about 10 cents per treatment is more likely. Cheap by any measure.
2. I've heard very little, if any residue left in the hive
3. I've heard it isn't stressful on bees (no queen loss, no loss of brood, no shutdown period)
4. You can treat without opening the hive
5. From videos I've seen, treating is easy
6. Difficult to overdose (not so much with MAQS or Thymol)
7. When you run out, you can just go to the hardware store (no need to pre-order, have it shipped in, worry about the bee store being "out of stock" as everyone and their cousin is treating this month)
8. Not temp. sensitive (can treat in spring, summer, fall, winter, day, night)
9. I haven't really heard of many people switching to OA and then deciding it wasn't a good choice

Cons:
1. Heavy upfront cost. ($100 entrance fee just to see if it works, plus the cost of the battery and the wood bleach).
Answer: Not a heavy cost at all considering the cost of purchased treatments. And there is no doubt that it works. Your car/truck battery will suffice.

2. Multiple treatments (like 3 or 4), each one week apart, are needed, making more labor and travel costs
Answer: True
3. Only kills phoretic mites (none under cappings)
Answer: True
4. Takes 60 seconds to treat, plus 2-10 min to cool down/circulate per hive (treating a yard of 25 hives would take 1.5 to 4.5 hours)
Answer: True, partially. The cool down period is much shorter. One minute at most, then you remove the vaporizer (cool it) and you're on to the next hive. On other treatments, how long would it take one to apply considering you must open and go through the hive?
5. (Kinda a big one for me) It's illegal (really don't want to get in trouble by state inspector, EPA, ect):
Answer : True, but consider this, it is used in almost the rest of the world as a mite treatment!
6. Make sure you keep your respirator close by
Answer: Absolutely! And stand up-wind.
7. PR issues (not a big concern, but doesn't look great to neighbors/bystanders when I pour wood bleach into a pan, jam a metal rod into the hive and hook it up to a car battery
Answer: They have no clue what you're doing. They'll think you're "jump-starting" your hive!


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## mitchgobears (Jan 26, 2014)

A "respirator" may not be adequate. Oxalic acid is a problem for mucous membranes: eyes, nose, mouth, lungs. You should be using a full face mask with a cartridge rated for organic vapors. This is the one I chose: 

http://www.amazon.com/gp/product/B007JZ1LG6/ref=oh_aui_detailpage_o01_s00?ie=UTF8&psc=1

As an eye doctor I see too many people who get chemical burns on their eyes from liquids or vapors. It is not worth it. With regard to legality, I don't know. In medicine we often use off-label treatments that are unapproved. Usually they become the standard of care as many providers find out the effectiveness and it saves the drug companies from additional research costs.


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## ericweller (Jan 10, 2013)

ABruce said:


> I am a new beekeeper this year, and have seven hives, After lots of reading I bought the vaporizer and the oxalic acid. One question I have not seen answered, unlike many other treatment options the OAV dissipates quickly. How does one ensure they get most of the field bees? Do they not have mites riding around on them waiting to come back and infest the colony all over again? Do you do the treatment later in the evening or very early in the morning to maximize the effect?
> thanks


I just finished a certification course and one of the lecturers said that the OA only works on phoretic mites which are those attached to adult bees. Since all of the mite's life cycle revolves around the bee brood, they normally do not travel far from it. The mites exit the cells attached to the newly emerged nurse bees. They hang onto the nurse bees until they are picked off or drop off by choice. They return to the larvae in the cells to reproduce. Since bees do not go foraging until very late in their life cycle, they do not typically have mites attached to them.
When you see a mite on a field bee, that means that means either it was one of the picked off ones that happened to attach to the field bee as it is leaving the hive or there is a mite explosion in the hive and there is a brood break so the mites have no larvae to feed off of so they attach any bee they can.
I was told to treat while most of the field bees are gone so the nurse bees and the open cells get treated thoroughly.
The lecturer said research seems to indicate that OA acts as an itching powder to the bees which makes them groom each other more intently and pick the mites off.
I would love to see an electron microscope picture of a mite that has gone through a OA treatment. I wonder if they appear more chewed as opposed to those that get picked off normally.


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## snl (Nov 20, 2009)

ABruce said:


> How does one ensure they (OAV) get most of the field bees?..... Do you do the treatment later in the evening or very early in the morning to maximize the effect?


Yes, early morning or later evening is best. Also, cloudy or drizzly days ........... However, if those times don't work for you, TREAT WHEN YOU CAN.


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## snl (Nov 20, 2009)

ericweller said:


> I was told to treat while most of the field bees are gone so the nurse bees and the open cells get treated thoroughly.
> From SNL: I disagree, you treat when most of the bees are there. OAV will coat them all.
> The lecturer said research seems to indicate that OA acts as an itching powder to the bees which makes them groom each other more intently and pick the mites off.
> From SNL: Research indicates that it destroys the bees cuticles (legs fall off) and it also clogs their breathing tubes.


For what it's worth...


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## ericweller (Jan 10, 2013)

You mean the mite's legs fall off, right? 
I would love to see an electron microscope picture of one after a treatment. I think that would be a great thesis research project.


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## Rader Sidetrack (Nov 30, 2011)

I looked, but did not find such a photo. What I did find was shots of apparently uninjured mites ...










Linked from this University of Florida page, which also has more similar photos:
http://entnemdept.ufl.edu/creatures/misc/bees/varroa_mite.htm


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## Specialkayme (Sep 4, 2005)

Fist, thanks for the input. It's greatly appreciated Mark. 

That being said:


snl said:


> 4. Takes 60 seconds to treat, plus 2-10 min to cool down/circulate per hive (treating a yard of 25 hives would take 1.5 to 4.5 hours)
> Answer: True, partially. The cool down period is much shorter. One minute at most, then you remove the vaporizer (cool it) and you're on to the next hive. On other treatments, how long would it take one to apply considering you must open and go through the hive?


When you get rolling, you are looking at 30 seconds a hive to treat with MAQS or Apiguard. Pull super off, insert product, put super back on.



snl said:


> 5. (Kinda a big one for me) It's illegal (really don't want to get in trouble by state inspector, EPA, ect):
> Answer : True, but consider this, it is used in almost the rest of the world as a mite treatment!


Not really something to consider. It's illegal in many of those countries as well. I visited a commercial beekeeper in Estonia this summer. Very eye opening experience. But he used OA, said it was illegal, but most of the inspectors just looked the other way. They don't have the treatment options we have. The EU (or maybe the Estonian government) doesn't approve of the use of formic acid pads (manufactured), Apistan, Apiguard, Apivar, or almost any other off the shelf product we have available to us. So what are they supposed to do? That's why inspectors look the other way. The commercial beekeeper said if he had the options we had, he'd use a legal treatment. 

Many people do coke around the world. Doesn't mean it's ok.

Ok . . . ok. . . comparing coke and OA may have been over the line . . . I get that . . . but you get my point.


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## BernhardHeuvel (Mar 13, 2013)

I just stumbled upon this: vaporized oxalic acid disintegrates into water, carbon monoxid and dioxid. But in between there is a step where oxalic acid disaggregates into formic acid and carbon monoxid/dioxid. 

In fact, the researchers of the very first days of vaporizing oxalic acids in beehives in Germany found, that after the vaporizing process, you can find 54 % of the oxalic acid still intact and additionally you find 1 % of the initial weight being formic acid. 

Now: by using 2 g oxalic acid per hive/treatment you end up with 1.08 g oxalic acid and 0.02 g formic acid in the hive. Right temperatures in the process supposed. Any temperature above 150 °C/302°F accelerates the degradation of the oxalic acid into water, carbon monoxid and carbon dioxid.

Compare that to a formic acid flash treatment, where about 30 ml formic acid are used per treatment (1 ml formic acid = 1.22 mg) => 36.6 mg => 0.0366 g

That means: after the vaporizing you have about 0.02 g formic acid in the hive => that is 20 mg formic acid. Which is more or less the same as a formic acid treatment with 16 ml of formic acid. 

So my conclusion is, with very little chemical knowledge of course, is that such vaporizing is a mild formic acid treatment. Is that right?


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## Redbug (Feb 8, 2014)

I am staying tuned...very interesting posts. 

Also Eric, Not just varroa but tracheal mites are killed by oxalic acid. So it's gotta be more than grooming.


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## snl (Nov 20, 2009)

From what I've read (and I really need to start keeping a better track & where I read it and who wrote it) OA vaporizes in the hive well before it turns to formic and carbon monoxide. Again, from what I've read, OA does not turn to formic and carbon monoxide except in lab conditions. I do believe that as CM would kill bees and of that, I see no evidence.

So, no .. I don't believe formic comes into play at all when vaporizing OA in beehives............


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## BernhardHeuvel (Mar 13, 2013)

Yes, made a mistake when calculating - because 1 ml is not 1.22 mg but 1.22 g. So the 0.02 g found after vaporization (I learned it is sublimation not vaporization) is similiar to 1.6 ml 100 % formic acid. Not 16 ml. So again even lighter as initially thought.


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## crofter (May 5, 2011)

You have it right snl

In a simple open evaporator the Oxalic acid vapor leaves the pan and receives no more heat input so its temperature starts to drop and it begins to condense in very fine crystals; that is what we see as white _smoke_. If you were to deliberately add more heat to the vapor you could raise its temperature further to the point of the chemical reaction into formic acid, carbon monoxide and water vapor that people catastophize about. That, as you say, would take laboratory or deliberate rather complicated process to accomplish.

A useful analogy is the transformation of water to steam _*at atmospheric pressure* _where the temperature will not exceed waters boiling point of ~212 F. That steam though can be _superheated_ to 500 or more degrees and still remain at atmospheric pressure. Superheating is not something that happens without deliberate effort.


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## Juhani Lunden (Oct 3, 2013)

Oxalic acid dripping is as effective as OAV and does not need any equipment.

Vaporized gas is a health hazard, do not heal!

How to make 3,2 % oxalic acid sugar solution for dripping:
100g sugar, 100 g water and 7,5g oxalic acid
warm water, pour sugar, stir to make clear, pour in acid crystals, stir... you are ready to handle nearly 10 hives.
Do not boil the ready solution.

28 ml is enough for any hive, do not use more 

do not use twice, because all acids are harmful for bees!

handle brood less time, 95% effect

I used it for 10 years


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## ericweller (Jan 10, 2013)

Juhani Lunden said:


> Oxalic acid dripping is as effective as OAV and does not need any equipment.
> 
> Vaporized gas is a health hazard, do not heal!
> ....
> ...


My concern of the OA dribble is it causes some bee loss. When the bees ingest it, it wreaks havoc with their digestion. 
Also, the OA dribble is done in the winter when the bees are clustered. I cringe at the thought of opening the hive in the start of winter and dribbling a liquid on the cluster. 
I do like the one treatment aspect of dribbling, though. I have 14 hives and I can count on 3 hours per treatment for all of them. I need to get another vaporizer to speed the treatment process.

Whatever works is the method you should use.


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## Robbin (May 26, 2013)

Redbug said:


> Just a comment or two...
> 
> I have just recently gotten a vaporizer to do 9 hives. After the first treatment and seeing how slow I was...I gave it some thought. Then I went to Walmart and bought four of the cheapie digital timers for about $4.50 apiece, (kitchen section). Using several timers at once...improved efficiency greatly. One timer is kept set at around 3 minutes for the burnoff time, and the other three timers are set for around 10 minutes. Using these several timers, you can just bump along hive to hive, with the 10 minute timers alarming when they are done...as you move along down the line. The secret to being efficient time-wise is to keep the vaporizer smoking with little lag time between hives. You can be two or three hives ahead of the last 10 minute timer counting down if you are fast enough.
> 
> My second comment...mentioned to me by a good friend...about using oxalic acid and not approved in this country. I am not selling any honey...I am just raising bees and expanding my apairy. It does not affect anyone but me and my bees.


If you can stand the extra cost, two vaporizers really speeds things up. I fire the second one up while the first is cooling, etc....


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## Juhani Lunden (Oct 3, 2013)

ericweller said:


> My concern of the OA dribble is it causes some bee loss.


Maybe 10 bees drop dead on the bottom

But if you give too big dose or too strong solution, the whole colony might die. I remember in the beginning some scientists gave 10% solution, and the whole colony just flew away, after becoming extremely nervous.
Dripping, I wonder if OAV too, might cause the bees to stay and keep the cluster a bit warmer whole winter, some beekeepers say they never settle down after it. That I not a good thing if winter is severe.


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## BernhardHeuvel (Mar 13, 2013)

Yes, that is the case. A friend of mine installed numerous temperature sensors throughout the hive. This before winter treatment:


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## BernhardHeuvel (Mar 13, 2013)

And this after the treatment:





The bees didn't go down with temperature after the treatment. For the rest of the winter. It seems you really wake them up when opening the hive in winter.


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## Oldtimer (Jul 4, 2010)

snl said:


> Me, I see mites in drone brood, I treat.........


Drone brood is mostly in the hives during main brood rearing season so would be interested if you could further expand on that in terms of any tips about using OAV effectively for treating hives with brood.


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## snl (Nov 20, 2009)

Oldtimer said:


> Drone brood is mostly in the hives during main brood rearing season so would be interested if you could further expand on that in terms of any tips about using OAV effectively for treating hives with brood.


Me, I see mites in drone brood. I treat...

As we all know, mites love to breed in drone brood over worker brood. Therefore, when I'm going thru my hives, I randomly open drone brood. If I see a that the brood is populated with mites, I'm sure mites are very much present in the hive and treat. Since OAV does not harm brood, bees or the queen but decimates mites, treating is an easy decision........


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## Oldtimer (Jul 4, 2010)

Any tips about how to do it effectively for hives with brood?

IE, do you use a series of treatments, etc.


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## snl (Nov 20, 2009)

Oldtimer said:


> Any tips about how to do it effectively for hives with brood? IE, do you use a series of treatments, etc.


I may do one or a series of treatment depending on what I find in the brood, if it's a lot of mites (i.e. opening brood and seeing mites in many, many cells) a series........ a mite in a cell here or there, one treatment.


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## Daniel Y (Sep 12, 2011)

ericweller said:


> I have 14 hives and I can count on 3 hours per treatment for all of them. I need to get another vaporizer to speed the treatment process.


I am working on a radically different approach. Based upon both past experience and a comment in this thread. Basically the aroma therapy candle suggestion.

I have in the past treated hives from the top with a similar method. This requires an empty box sufficiently tall to cover the device.

In my case I used hooka coals as a heat source and a small metal cup I got from Wal Mart. The cup set directly on top of the coal the coal set on a small metal dish and the entire mes was placed on the top bars of a hive and covered with a box constructed specifically for the purpose. in my case I made the tip of the box glass so I could observe the vaporization process. One interesting observation from this method is that the bees actually fan the OA vapor through the hive.

Some of my concerns are.

1. open flame in the hive for unlimited period of time. open flame at all is not good. bees do contact flames. bees do burn. burning bees running around in a hive equals very bad things possibly happening.

2. keeping the cost per unit as small as possible.

Number one can be addressed in several ways. either shield the flame or limit how long it remains. Possibly not using open flame at all.

In looking around I realized that tea light cups would serve well as vaporization trays. I have found them as low cost as just under 5 cents each.

Tea lights themselves as a heat source I do not have a price for. I do know they are relatively cheap and burn for hours with continuous use. 

Cost of OA has repeatedly been estimated at around 5 to 10 cents per treatment.

One remaining question is what sort of rack or stand to hold it all on. I am able to do some pretty fancy stuff with wire bending and suspect I could come up with something in fairly large numbers at no more than cost of time. but that is not an answer for everyone. I would rather have off the shelf items anyone has access to.

Any suggestions of a rack or stand that is a fairly common item are welcome.

The most costly part of this method I suspect will be an adequate number of empty boxes but here are my rough preliminary numbers as to cost of say 10 set ups. I picked 10 assuming it woudl take 1 minute to set one up. this means you could set up ten in the time you woudl then need to return and remove the first one form the first hive and make it ready to be reused.

10 tea light cups at 5 cetns each 50 cents.
10 stands I am allowing $1 each for based uon some early ideas. $10
10 t4ea candles you can get them in bags of 25 for about $3 so i will say 3 bucks.
OA is about $10 for a lb.
10 empty supers at $8 each $80

So you have $103.50 in cost to start. $10 ongoing replacement cost of OA plus cost of candle replacement. the rest of the equipment is permanent one time cost.

Continuous annual treatment cost after start up cost is about 50 cents per hive. Time issue has been eliminated.

I prefer a system that is more place it and forget it and am working along that line. Elimination of that empty super is the most necessary detail in that case.


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## Stephenpbird (May 22, 2011)

Daniel Y said:


> In looking around I realized that tea light cups would serve well as vaporization trays. I have found them as low cost as just under 5 cents each.
> 
> Tea lights themselves as a heat source I do not have a price for. I do know they are relatively cheap and burn for hours with continuous use.


An empty tea light cup works well as a vaporization tray. Push with your thumb on the underside of the cup to form a small indentation, creating a place for the OA. Punch some small holes in the side of the tray to let in air. Place this upside down over a burning tea light. Keeps the bees away from the flame and it does actually work well.



Daniel Y said:


> One remaining question is what sort of rack or stand to hold it all on. I am able to do some pretty fancy stuff with wire bending and suspect I could come up with something in fairly large numbers at no more than cost of time. but that is not an answer for everyone. I would rather have off the shelf items anyone has access to.
> 
> Any suggestions of a rack or stand that is a fairly common item are welcome.


a saucer or plant pot with sand (reduces the chance of a fire, the tea lights can get quite hot on the bottom surface) in it works well.



Daniel Y said:


> The most costly part of this method I suspect will be an adequate number of empty boxes but here are my rough preliminary numbers as to cost of say 10 set ups. I picked 10 assuming it would take 1 minute to set one up. this means you could set up ten in the time you woudl then need to return and remove the first one form the first hive and make it ready to be reused.


The super is used because the treatment is usually done after the harvest, with our type of management they normally are empty and at hand at this time.


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## Gypsi (Mar 27, 2011)

I'm going to get some sticky boards in my hives and find out if I even have a varroa problem. Brood breaks have happened when I forgot to feed.


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## Stephenpbird (May 22, 2011)

Maybe a few pictures would help inspire you 

http://www.imker-schwaebisch-gmuend.de/8393.html

http://www.einfachimkern.de/viewtopic.php?f=46&t=476

http://www.einfachimkern.de/viewtopic.php?f=11&t=1221&start=30

links are to German sites but you can use google translate if you can't read German.


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## Daniel Y (Sep 12, 2011)

Thank you Stephen, very helpful suggestions. I like the permanent/semi permanent burners.


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## JasonERD (Feb 7, 2013)

I am also considering an oxalic acid vaporizer. how long after a treatment does it take to start seeing mite kill (on removable bottom board)... and how long does it work until the treatment wears off?

Once the treatment wears off, does that mean the thin coat of crystals inside the hive are gone?


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## Robbin (May 26, 2013)

camero7 said:


> i use 2 vaporizers when treating my yards. I spend less than 2 minutes per hive. I don't block the entrance or bother with sealing the hive. I put one in a hive, load the other one, by that time the first is done and I pull it out, dip it partially in water, load it, pull the other one and so on. I use a battery pack with clips to hook it up to the power so I'm not wasting time. My yards are all around 25 hives and I'm in and out in about 45 minutes total if all I'm doing is treating. I like not having to lift or fight the bees. I do almost all of my vaporization with just a veil. I've never bothered with a mask, just know which way the wind is blowing. A little whiff will make you cough a little but it's over quickly. BTW- I've been getting a very good mite kill with 3-4 treatments.


I follow about the same procedure, my vaporizers are on boards that block the entrance while in use. I use two, heating one with the other cools in the hive, then move and start the next hive while the second cools. I light a smoker and watch it like a hawk. I hate a mask so I'm very cautious.


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## Robbin (May 26, 2013)

JasonERD said:


> I am also considering an oxalic acid vaporizer. how long after a treatment does it take to start seeing mite kill (on removable bottom board)... and how long does it work until the treatment wears off?
> 
> Once the treatment wears off, does that mean the thin coat of crystals inside the hive are gone?


Mite drop starts in hours, but the 24 - 48 hour or second full day is when they really drop. I mean THOUSANDS, if you have a heavy infestation. I've never seen anything in the hive, I think the crystals are very small.


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