# Does oxalic acid leave long term residues in the hive?



## wildbranch2007 (Dec 3, 2008)

here is some good reading for the new year

Oxalic acid residues 

Just before the spring treatments the mean natural concentration of oxalic acid (±S.E.M.) was measured to be between 19.56±0.83 ppm and 35.85±5.96 ppm in the three experimental groups (FIGURE 3). Eight days after the treatment the oxalic acid concentration was increased in the treated groups compared to before treatment but only the increase in the sprayed group to 62.84±15.88 was significant (K-W, p<0.05). At the first honey harvest in June the mean natural concentration of oxalic acid (±S.E.M.) was measured to be 37.78±5.55 ppm in the sprayed group, 41.56±8.54 in the trickled group and 57.70±7.95 ppm in the control group. There was no significant difference in oxalic acid concentration between the groups at any of the sampling dates (K-W, p>0.05). 



http://www.beekeeping.com/articles/us/spring_treatment_oxalic_acid.htm


added here is what canada says about it

http://hc-sc.gc.ca/cps-spc/pubs/pest/_decisions/rd2010-12/index-eng.php#a


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## BEES4U (Oct 10, 2007)

Nathen,
You might investigate o.a. vaporizing.


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## sammyjay (May 2, 2011)

wildbranch2007 said:


> There was no significant difference in oxalic acid concentration between the groups at any of the sampling dates



Does that mean that there was not any significant difference between the colonies that got treated with oxalic acid and the ones that were not?


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## sqkcrk (Dec 10, 2005)

It appears that there was no significant difference between those treated and the control hives, those not treated. If I read what was written correctly. It also appeared that at honey harvest time there was more OA present in the control colonies than in ones treated. Though, perhaps, insignificantly so.

Which to me indicates OA is safe to use in treating bees. BUT, Michael Palmer will warn you that vaporizing it is dangerous to humans. Which it is. As will others. 

I know people who use it as part of their annual IPM Program.


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## Michael Bush (Aug 2, 2002)

Residue isn't what worries me about organic acids. Formic and Oxalic both occur in honey naturally and the amounts in honey with and without treatments are not different enough to detect. The problem is they disrupt (actually pretty much wipe out) the microbes in the hive and the Oxalic when trickled will damage the Malpighian tubules (kidneys) of the bees and shorten their lives. 

http://www.bushfarms.com/beesmorethan.htm
http://www.bushfarms.com/beesfoursimplesteps.htm#notreatments


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## Vance G (Jan 6, 2011)

I have heart failure and getting a whiff of it the other day did me very little good. I decided the experiment was over after treating two hives. Had a real good cross wind too.


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## sammyjay (May 2, 2011)

Michael Bush said:


> Oxalic when trickled will damage the Malpighian tubules (kidneys) of the bees and shorten their lives.



I have heard that, but I've also heard that that doesn't happen when vaporized.


Just so that I'm clear, I don't want to use it. I want to regress to small cell and quit treating. But I want to treat until the varroa mite population stabilizes, like you(correct me if I'm wrong) did while you regressed.


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## rainesridgefarm (Sep 4, 2001)

The shorten lives is like saying by eating butter you will live to be 88 intead of 89. When you look at the damage done by the varroa oxalic acid is wonderfull if you use it correctly. As for the microbes they are replaced in hours of treatment.


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## Michael Bush (Aug 2, 2002)

It shortens their lives enough that if you drizzle twice most won't make it to spring.


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## BEES4U (Oct 10, 2007)

Vance G,
What method did you use to vaporize the oxalic acid?


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## FlowerPlanter (Aug 3, 2011)

Are there any advantages to using oxalic vapor over oxalic drizzle? Any disadvantages?


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## rweakley (Jul 2, 2004)

Drizzeling seems to have a limit to how many times you can do it a year because it is bad for their kidneys (yeah I don't remember the real term), vaporizing you have to worry about inhaling it yourself, but can be done over and over to the bees and there doesn't seem to be a problem (with in reason). I vaporize probably 2 or 3 times a year about a week apart in the fall. When I treat at all.


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## kjbann (Jun 30, 2009)

There are tons of posts about oxalic acid on the British forum http://www.beekeepingforum.co.uk/
It seems most of the Europeans favor trickling. I perused a lot of the European studies a while back and the amazing thing was that a lot of them showed less OA in ppm in treated hives than in untreated hives. I've never understood that, but I was glad to see that treated hives overall showed no increased levels. I vaporize with a 12 volt rig and it works well for me. I can see the vapor if any comes out of the hive, and I know from experience that I don't want to breathe it. Not sure if it is harmful, but it isn't nice, so I stay up wind. Next year I think I'll do like Rod and give them a few treatments in time for fall brood instead of just one in November.
Ken


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## rainesridgefarm (Sep 4, 2001)

Well I do not know what I am doing right then because I drizzled OA three times in the fall of 2010 and three times in the fall this year with out losing any hives. Once a month for three months each time. once in IL and twice in MS. Of course this was to brighten the wooden ware of my hives not to treat mites so maybe that had something to do with it.


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## beekuk (Dec 31, 2008)

Michael Bush said:


> It shortens their lives enough that if you drizzle twice most won't make it to spring.


Efficacy of repeated trickle applications of oxalic acid in syrup for varroosis control in Apis mellifera: influence of meteorological conditions and presence of brood.
Bacandritsos N, Papanastasiou I, Saitanis C, Nanetti A, Roinioti E.
Source

Institute of Veterinary Research of Athens, National Agricultural Research Foundation, Neapoleos 25, Agia Paraskevi 153 10, Greece. [email protected]
Abstract

Oxalic acid field trails for the control of varroosis (Varroa destructor) were carried out in an apiary located on the Mt. Imittos (Attica, Greece). The colonies received four successive applications (approximately one every 16 days) with 4.2% oxalic acid (OA) and 60% sugar solution by trickling method with two alternative types of syringes (an automatic self-filling dosing and a single-use) from the broodright to broodless period. The results indicate that the first three applications (from 6th October to 25th November-broodright period) resulted in 65.3% cumulative mite mortality, while only the last application (after the 26th November-broodless period) resulted in 77.3% mite mortality. Very low outern temperatures reduce to the minimum the bee movability, which may result into a slower development of the OA efficacy. No poor colony growth or queen loss were observed even if the bee colonies were received the four successive OA applications with the last one taken place at a very low outern temperature (6.2 degrees C). The trickling method using an automatic-filling syringe seems to be a very quick way for applying oxalic acid in large apiaries (approximately 150hives/h).

http://www.ncbi.nlm.nih.gov/pubmed/17624673


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## Axtmann (Dec 29, 2002)

IMO that’s all depends on the climates. Probably not be a problem in Greece where bees can fly for cleaning during winter (if they have winter). What’s happen if they must stay inside for several weeks or even month? They talking about a very low outside temperature 6.2 C, this is approx 45 F. In Greece, they have this (low) maybe for a few days before the temperatures are up again. The bad result, 77.3% mite mortality, is because bees breeding 12 months of the year.

You should bring us a field trail from a country with a long winter.


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## beekuk (Dec 31, 2008)

Axtmann said:


> You should bring us a field trail from a country with a long winter.


 Perhaps we could take it in turns,i find one for a warmer climate,like Greece,some states in the USA ect,and you could find one for the colder area's, one that states exacly what harm oxalic does to the bees. It can certainly kill them in a short period of time if they have a slightly high nosema count.


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## JD's Bees (Nov 25, 2011)

Oxalic treatments work best when no brood is present, up to 95% for sublimation. Since you would have to wait until late Oct. to Nov. this would leave the colony at risk during fall while they are producing winter bees. I wouldn't recommend oxalic as your only method of treatment if varroa levels are high in summer.


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## megank (Mar 28, 2006)

Nobody I know of drizzles more than once per season


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## beekuk (Dec 31, 2008)

JD's Bees said:


> I wouldn't recommend oxalic as your only method of treatment if varroa levels are high in summer.


 I would not recommend, or use oxalic acid via the trickle method at all,if you really need to use this, then your earlier treatments have failed,and any young bees may very likely have been badly violated by the mites, and their associated viruses.


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## Mike Gillmore (Feb 25, 2006)

The problem I see with the single trickle method in the Northern US and Canada is that the recommendation is to apply only one treatment in the broodless period, late in the season. By then the damage has already been done, many times it's too late if the mites loads are very high. The treatment may have terrific efficacy at that point, but bees stressed by heavy mite infestation are already in decline and will struggle to make it through winter. 

I like the two pronged approach. In late summer when the mite levels are skyrocketing treat with OA Vapor, 3 treatments one week apart. This will knock down a fairly high percentage of phoretic mites and allow for a healthier colony moving into late Fall/early Winter. Then when they are broodless treat with a single trickle of OA to clean them up.


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## kjbann (Jun 30, 2009)

Mike Gillmore said:


> The problem I see with the single trickle method in the Northern US and Canada................ In late summer when the mite levels are skyrocketing treat with OA Vapor, 3 treatments one week apart. This will knock down a fairly high percentage of phoretic mites and allow for a healthier colony moving into late Fall/early Winter. Then when they are broodless treat with a single trickle of OA to clean them up.


Mike,
What would be wrong with using vapor for the late year treatment as well?
Ken


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## danno (Dec 17, 2007)

I agree completely with Mike and using vapor for a late treatment is not a problem to answer kjbam's question. I treat just as Mike does 3 times a week apart in late summer and have a few mite free brood cycles before winter sets in. I use a 12 volt burner with 25 foot of cord, wood bleech and NO resporator because I'm 25 ft away during the burn. I also do another 3 rounder in late spring. 3 treament 2 time a year does take a bunch of time but little money. I dont have a mite problem on my colonies. The mites do have a Dan problem though


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## Mike Gillmore (Feb 25, 2006)

kjbann said:


> Mike,
> What would be wrong with using vapor for the late year treatment as well?
> Ken


Nothing at all, I'm sure that will work very well also. But I think there may be a general opinion, which may or may not be accurate, that Trickle is more effective on a broodless colony than Vapor would be. 

I guess my main point is that in some areas of the country relying on a single trickle in late fall/early winter may not be enough if nothing is done to knock down mite loads when the numbers skyrocket in late summer. I've seen the difference, the mites really need to be dealt with when their number peak or the colony suffers terribly going into winter.


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