# oxalic acid



## beeware10 (Jul 25, 2010)

I don't believe getting immune is a problem. the best article is by randy oliver at scientific beekeeping. we have used the dribble method with good results. as a bonus its the cheapest treatment available.


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## BadBeeKeeper (Jan 24, 2015)

cata_rebel said:


> Before that I used any kind treatments and *I remember we have to switch medication almost every year because varoa in time is get it immunization on some medication*
> How is this problem regarding oxalic acid?
> Dis Varoa got immune do I have to switch treatments every year?


Varroa have demonstrated resistance to the three synthetic miticides, fluvalinate, amitraz and coumaphos. However, they have apparently not demonstrated any such resistance to formic acid. I would suspect they they would similarly lack [the ability to develop] resistance to oxalic acid, _but I am not aware of whether or not this has been conclusively shown_.

I still have some Apistan (fluvalinate) left, and am considering an experiment with it this Spring...if I can get my stuff together enough to be able to conduct it in the appropriate scientific manner.


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## bean tree homestead (Nov 18, 2013)

http://scientificbeekeeping.com/oxalic-acid-questions-answers-and-more-questions-part-1-of-2-parts/


Mode of Action

Many plants use oxalic acid, and/or its oxalate salts, to discourage insects and large animals from eating them. This leads us to the hope that OA might be a long-term “organic” weapon for mite control. Funny thing is, no one really knows how OA kills mites, although there is a great deal of conjecture in the literature! One might assume that its mode of action would be similar to that of formic acid, which forms a vapor at hive temperatures. According to Imdorf (Anonymous 1999), formic kills by “respiratory inhibition,” although he doesn’t cite a source for this statement.

A number of authors hypothesize that OA also sublimates in the hive. However, if they would read a chemistry text, they’d see that oxalic acid does not sublimate to any extent (as evidenced by the porous sacks in which it is sold wholesale, and the lack of odor) at normal temperatures. The vapor pressure (measure of a substance’s propensity to evaporate) of oxalic acid is less than 0.001 mm Hg @ 20C (68F). For comparison, the vapor pressure of paradichlorobenzene (mothballs), which readily sublimates, is 0.6 mmHg—more than 600 times as strong. I think we can rule out sublimation as a mode of action (or as a health hazard).

So, is it the acid or the oxalates that affect the mite? In European research (Nanetti, in Anonymous 1999) the efficiency of oxalic acid was compared to neutral potassium oxalate. They determined that it is the acidity, rather than the oxalate ion, that kills varroa.

We still didn’t know whether the acidity of OA killed the mite through ingestion of acidic bee “blood,” or by direct contact. Ellis and Aliano (2005) performed a clever experiment: By splitting single dequeened colonies with various dividers, and treating only one side, they found that oxalic is apparently transferred through the colony by bee body contact, rather than through trophallaxis (mouth-to-mouth transfer), and distributes well by such contact (80% kill on treated side, 65% kill on untreated).

OK, so OA spreads and kills by contact—that’s why heat vaporization (to be covered in the next installment) works well. We still don’t know how it gets into the mite’s body (no one’s proposing that mites crawl around licking the stuff up). We do know that oxalates in plants form spiky crystals that can penetrate animal tissue, similar to those of boric acid (commonly used for ****roach and ant control). Boric acid forms abrasive spikes that can penetrate the soft integument at the joints of the insect exoskeleton, and apparently desiccate the insect. It also acts as a stomach poison to ants.

Could oxalic acid work in the same manner? Heat vaporized OA does form tiny spiky crystals, as does OA evaporated from a water solution. But oxalic dissolved in sugar syrup dries to a clear, smooth, candy that shows no crystal structure (personal microscopic observations). The rub is, OA is only effective when dribbled in a sugar solution (Anon 1999), not in plain water. So go figure! We’ll leave the mode of action discussion at that…


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## cwood6_10 (Apr 17, 2012)

When I was at a beekeeping seminar someone from Texas A&M department of agriculture told us that OA was going to be approved this year for use in hive. Am I mistaken and we can use it in hives? I see people that have used it but I don't want to break that law since I will be a register apiary this year and be inspected. Information on the legality of OA would be appreciated.


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## snl (Nov 20, 2009)

I believe we can look to Europe for some answers as to mite immunity to OA. While I can find no definitive studies that say Yay or Nay, Europe has used OA extensively for 10+ years, and there is no reported mite immunity to OA. While one can never say never, after 10+ years of use, there is not ONE reported incidence of mite developed immunity to OA.......that in itself says something.........


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## snl (Nov 20, 2009)

cwood6_10 said:


> When I was at a beekeeping seminar someone from Texas A&M department of agriculture told us that OA was going to be approved this year for use in hive. Am I mistaken and we can use it in hives?


Yes, it will be approved in a matter of months......... if you wish to wait for "official approval," that is of course up to you......


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## Mike Gillmore (Feb 25, 2006)

There are some who believe that over time, with consistent use of OA, only the strongest mites will survive. This will lead to a generation of super-mites, more tolerant of the acid, which will reduce the effectiveness of treatments. 

I suppose that's a possibility. Time will tell. I've been using it for about 7-8 years and it still works just as well now as the first time I tried it. Haven't found any super-mites yet, they keep dropping. I may eat my words one day, but it's working for now.


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## johno (Dec 4, 2011)

Not so sure about the story of mites developing resistance to amitraz, I think tests were done to check the efficacy of apivar and they found that the mites were not dying quickly as they were with fluvalinate and caumaphos so figured that the mites were becoming resistant. However apivar is a longer term ascaricide that takes more time to do the mites in. It was stated that amitraz has been used in Europe for 30years I think with no sighn of mites becoming resistant to it. Time will tell.
Johno


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## beepro (Dec 31, 2012)

Johno, over here we have an older Russian man looking for
amitraz 12% I think. But it was illegal for the honeybee 
mite treatment some years ago saying bad for the bees and queen too.
Apparently some beekeepers complaint and the EPA made them illegal.
Between OAV and amitraz, I think I will use the less harmful chemical.
So if the mites can be destroy by the amitraz then how come every year he is using them. 
Maybe he still think that the mites have not became resistant to this chemical yet. And he's still using it.


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## papabear (Mar 5, 2014)

cwood6_10 said:


> When I was at a beekeeping seminar someone from Texas A&M department of agriculture told us that OA was going to be approved this year for use in hive. Am I mistaken and we can use it in hives? I see people that have used it but I don't want to break that law since I will be a register apiary this year and be inspected. Information on the legality of OA would be appreciated.


a friend of mine came over this year in November an bleached my hives.
I ordered 1 so I can bleach the wood myself.

Stumpy Lake Bee Farm


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## johno (Dec 4, 2011)

Beepro, I have been using formic acid 50% and fume pads for years I also use OAV at the end of summer and in the fall. Just mentioned the amitraz story as there was quite some talk about it on B-L and was causing a little panic I think.
Johno


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## oldforte (Jul 17, 2009)

papabear.... get any side benefits from bleaching your hives?


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## Redbug (Feb 8, 2014)

snl said:


> Yes, it will be approved in a matter of months......... if you wish to wait for "official approval," that is of course up to you......


That's interesting...There really is a glimmer of approval coming down the pike? How did the chemical lobby fail to convince the FDA?


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## cata_rebel (Jun 26, 2013)

I Ben used OA whit good results I was wondering if they got imune to the OA 
How about the tracheal mites is it OA doing anything about it ?


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## cata_rebel (Jun 26, 2013)

cata_rebel said:


> I Ben used OA whit good results I was wondering if they got imune to the OA
> How about the tracheal mites is it OA doing anything about it ?[/QUOTE
> Also people do what u think is ok for u bees
> FDA is some federal regulations if u are not business they don't have right about your apiari
> ...


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## beepro (Dec 31, 2012)

Well, if you don't drink milk then you will not feel it no matter how they regulate the milk industry.
They can regulate the sale to the public but cannot regulate the sale to the animals. So you
can still sell to feed the cat or dog, etc.


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## 78-79fordman (Mar 23, 2014)

cata_rebel said:


> cata_rebel said:
> 
> 
> > I Ben used OA whit good results I was wondering if they got imune to the OA
> ...


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## gbsnplr (Jan 18, 2015)

I purchased the Varrox OAV can I use a motorcycle battery or does it have to be a car battery?


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## snl (Nov 20, 2009)

Any 12v battery will do. I suggest you "test fire" the vaporizer prior to use just to see how long vaporization will take. Normally 2.5 minutes will do it but that depends on the condition of the battery in use..........


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## gbsnplr (Jan 18, 2015)

Great, thanks for all the help.


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## papabear (Mar 5, 2014)

oldforte said:


> papabear.... get any side benefits from bleaching your hives?


yea killed mites !!!!!!!!


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## Mike Gillmore (Feb 25, 2006)

gbsnplr said:


> I purchased the Varrox OAV can I use a motorcycle battery or does it have to be a car battery?


It depends on how many hives you are treating before recharging the battery. Prior to buying a car battery I was using a lawn tractor battery and after about 8 colonies you could tell it was losing steam. It started to take much longer to vaporize the acid.


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## gbsnplr (Jan 18, 2015)

I will only have 2 colonies starting the 11th of April


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## red (Jan 15, 2013)

I have been running two of the varrox models off of my toyota tacoma at the same time. It takes about five minets for mine to fully vaporise. I was wondering if the higher altitude has anything to do with the burn time?


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## Mike Gillmore (Feb 25, 2006)

It might.
I also use a Varrox and it should take no more than 3 minutes with the battery hooked up to vaporize 2g, plus an extra 1 1/2 minutes in the box after disconnecting the power lead.

Maybe your cable is too heavy and draining charge?


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## crofter (May 5, 2011)

Two vaporizers should not be a considerable load. My VW used 4 such glow plugs and I would cycle them three times before attempting a start in sub zero weather.

Physics says that lower atmospheric pressure (higher elevation) will take fewer Btu's input to boil off a substance but I dont know if it would be readily noticeable timewise. If it is slower than you think it should be I would consider loosening off, wiggle and reset the glow plug in the tray.


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## snl (Nov 20, 2009)

red said:


> I have been running two of the varrox models off of my toyota tacoma at the same time. It takes about five minets for mine to fully vaporise. I was wondering if the higher altitude has anything to do with the burn time?


It could. But, do you have an extra length of cable between the vaporizer cord and the battery? If so, that would readily explain the additional time as the additional wire length "waters" down the power coming from the battery.


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## snl (Nov 20, 2009)

crofter said:


> If it is slower than you think it should be I would consider loosening off, wiggle and reset the glow plug in the tray.


The Varrox is not a glow plug based vaporizer, but is rather uses resistance heating.......


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## crofter (May 5, 2011)

snl said:


> The Varrox is not a glow plug based vaporizer, but is rather uses resistance heating.......


My bad! I was thinking Heilyser which is glow plug based I believe.


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## red (Jan 15, 2013)

I have both vaporizers hooked to a twenty five foot exstention cord with a side by side plug in on the end of it. This could be my problem.


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## snl (Nov 20, 2009)

red said:


> I have both vaporizers hooked to a twenty five foot exstention cord with a side by side plug in on the end of it. This could be my problem.


It's not a problem, it just takes longer to vaporize with the additional footage......


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## Rader Sidetrack (Nov 30, 2011)

The vaporizers that _snl _sells are 150 watts, and competing models are probably similar. At 12 volts, each unit will draw approximately 13 amps. If you have two on them on the same extension cord, then the combined vaporizer load will be 26 amps. 

If you are using light/cheap extension cord, say a 16 gauge extension cord commonly sold, that 26 amps is overloading the cord somewhat. That overload will result in some of the electrical power being used to heat up the cord itself, and vaporizing will take longer due to the power lost to the cord heating. That heating of the cord can be reduced by using a heavier gauge extension cord. A 12 gauge cord would be a better choice - or use two separate cords.


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## Tcqf (Feb 3, 2015)

Hello I ve been using OA for 8years and no other treatments,and no problems.using the vaporizer is the best method in my opinion as very little disturbance to the bees,no need to open the hive,no bee deaths and high mite drop and can bee used multiple times unlike the drizzle which can only be used once and causes the bees to ingest the acid.each treatment cost a few pence(sorry cents) may be that's why it s not legal in the USA selling all the strips and treatments is big business? I find treated hives produce much more brood.


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## snl (Nov 20, 2009)

Tcqf said:


> Hello I ve been using OA for 8years and no other treatments,and no problems.using the vaporizer is the best method in my opinion as very little disturbance to the bees,no need to open the hive,no bee deaths and high mite drop and can bee used multiple times unlike the drizzle which can only be used once and causes the bees to ingest the acid.each treatment cost a few pence(sorry cents) may be that's why it s not legal in the USA selling all the strips and treatments is big business? I find treated hives produce much more brood.


Shortly, those who have seen the wisdom in the usage of OAV as a mite treatment will "legally" be able to protect their hives from mites once OA is approved for use in beehives. We're almost there.........


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## cata_rebel (Jun 26, 2013)

Does oxalic acid have any effect on tracheal mites?


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## cata_rebel (Jun 26, 2013)

cata_rebel said:


> Does oxalic acid have any effect on tracheal mites?


I find my answer myself 

A common control for them is a grease patty (sugar and cooking grease mixed to make a patty) because it masks the smell that the tracheal mites use to find a young bee. If they can't find young bees, they can't chew through the spiracle in old bees to get in and so they can't reproduce. Menthol is commonly used to kill the Tracheal mites. FGMO and (by some reports) Oxalic acid will also kill them. Breeding for resistance and small cell are also useful

Michael Bush 

http://www.bushfarms.com/beespests.htm


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## snl (Nov 20, 2009)

It is thought so, but unproven.


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## oldforte (Jul 17, 2009)

Tcqf said:


> Hello I ve been using OA for 8years and no other treatments,and no problems.using the vaporizer is the best method in my opinion as very little disturbance to the bees,no need to open the hive,no bee deaths and high mite drop and can bee used multiple times unlike the drizzle which can only be used once and causes the bees to ingest the acid.each treatment cost a few pence(sorry cents) may be that's why it s not legal in the USA selling all the strips and treatments is big business? I find treated hives produce much more brood.


How often do you treat....spring and fall?


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## Tcqf (Feb 3, 2015)

Winter only,that seems to be enough regards tcqf


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## Thershey (Mar 12, 2014)

snl said:


> It is thought so, but unproven.


Larry... I am a customer of yours, love my new vaporizer BTW, but am a bit confused about your answer here. The following quote comes directly from your website and is also contained in the packaging.

*"The vaporization of oxalic acid in beehives is a proven method of killing both Varroa & Tracheal mites. "*

I have both varroa and tracheal mites in my hives and thought I was purchasing a device/method that would treat for both. Can you please explain the difference in your statement above vs the statement on your packaging and website? Not meant to be a gotcha question but I need to know if I should be doing something different to treat the tracheal mites.


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## snl (Nov 20, 2009)

Thershey said:


> Larry... I am a customer of yours, love my new vaporizer BTW, but am a bit confused about your answer here. The following quote comes directly from your website and is also contained in the packaging.
> 
> *"The vaporization of oxalic acid in beehives is a proven method of killing both Varroa & Tracheal mites. "*
> 
> I have both varroa and tracheal mites in my hives and thought I was purchasing a device/method that would treat for both. Can you please explain the difference in your statement above vs the statement on your packaging and website? Not meant to be a gotcha question but I need to know if I should be doing something different to treat the tracheal mites.


Not a gotcha question at all. It is a proven the OA will kill VM and there are many studies that prove so. As to TM, the best material I've found says that OA does, however I cannot find a _*study*_ that proves beyond a shadow of a doubt that confirms so. Those researchers that have used OAV have not had a TM. There is anecdotal evidence that it does kill TM.


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## Thershey (Mar 12, 2014)

snl said:


> Not a gotcha question at all. It is a proven the OA will kill VM and there are many studies that prove so. As to TM, the best material I've found says that OA does, however I cannot find a _*study*_ that proves beyond a shadow of a doubt that confirms so. Those researchers that have used OAV have not had a TM. There is anecdotal evidence that it does kill TM.



Thank you for responding. No doubt that it's putting a serious hurt on the varroa mites. Finished the 2nd treatment Sunday and they are falling like rain.


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