# True Statement? "OA will not harm either brood or the queen."



## Rusty Hills Farm (Mar 24, 2010)

Cannot speak for vaporizing OA, as I have never vaporized, but when it is used as a dribble, it can cause _very_ mild brood damage. When it is used in the spring, they seem to come on like gangbusters after usage. However, if you dribble more than once on *winter* bees you can damage your bees, shortening their lifespans at the very time you need them to live the longest.

I have used OA as a dribble for a number of years, never more than once a year and only in the years when they need it, with good results. This year, for instance, I had no mites in my last mite check, so I did not dribble. However, I am in the deep south so my winter bees do not need to survive nearly as long as your northern winter bees do, and I do think this makes a difference in my results.

JMO

Rusty


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## David LaFerney (Jan 14, 2009)

I've used it both when hives had brood and when they didn't and have never been able to detect any negative effects at all.


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## jrbbees (Apr 4, 2010)

Many statements will be found to untrue if you push the variables. 

Make the acid stronger, treat too many times, close them up too long after treatment, etc.

You can kill a child by making them drink too much water, booze in reasonable moderation rarely is a factor in car accidents, too many vitamins will kill you, too little salt and you die - too much does the same thing in a different way.

Sadly most things require a degree of "following the instructions" or moderation.


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## BernhardHeuvel (Mar 13, 2013)

*Short term negative effect of oxalic acid in Apis mellifera iberiensis*
R Martín-Hernández, M Higes, JL Pérez, MJ … - Spanish Journal of Agricultural Research, 2007
http://dialnet.unirioja.es/servlet/articulo?codigo=2486272&orden=142406&info=link

*Cell death in honeybee (Apis mellifera) larvae treated with oxalic or formic acid*
http://www.edpsciences.org/articles/apido/pdf/2004/05/M4027.pdf

Summary
*Select colony-associated fungi (bee isolates), Absidia sp., Ascosphaera apis, Aspergillus flavus, Fusarium sp., Penicillium glabrum, Mucor sp., showed a* 40% reduction in radial growth rate with formic acid, *a 28% reduction with oxalic acid*, and a 15% reduction with fructose and highfructose corn syrup (HFCS) when grown on supplemented media at 30°C to mimic colony conditions. No effect, suppressing orpromoting growth, was observed on other colony-associated fungi, Alternaria sp., Aspergillus niger, Cladosporium cladosporioides, Rhizopus sp.and Trichoderma sp., except 0.1 M formic and oxalic acid. Sensitivity to these compounds did not correlate with the fungus species being aslow- or fast-grower and sensitivity to one compound did not translate to sensitivity to another compound. Given the competitive natureand high-sporing (conidia) activity of these species, our results suggest that alteration or disruption of the colony\mycoflora can occur by use of these compounds. This may indicate a possible link between compound application and incidence of bee fungal pathogens. 
http://ddr.nal.usda.gov/bitstream/10113/17780/1/IND44075806.pdf

*Sublethal effects of oxalic acid on Apis mellifera*
Apidologie (2012) 43: 218-225; Schneider, Eisenhardt, Rademacher
http://hal.archives-ouvertes.fr/docs/00/93/03/04/PDF/hal-00930304.pdf

Also see: http://www.jiventure.info/Overview_of_Pesticides_and_Antibiotics_Used_in_Beekeeping

To sum it up in my own words, oxalic acid does harm the gut of the bees and it softens the chitin skin of the bees. It has a sublethal effect on bees which can be seen by a slightly slower brood development in Spring. It also has it effects on the microbiom of the bee hive. (It has been found, that it doesn't harm the pseudoscorpions in a hive, on the other hand.)

So as is with every sort of chemical treatment it does some harm. I find it a mild treatment compared to other treatments. From my experience vaporizing is not reliable enough. You have to treat when the cluster is not tight yet and some brood is present. If brood is present you have to treat at least three times every two weeks, most treat four times. Some remove all brood combs and treat two times. Too much work for me. I stick with dribbling. There are lot of possibilities why vaporizing can fail and sometimes it does. Nothing can go wrong with dribbling (with the exception you completely drench them).

When dribbling swarms or splits in summer you find dead bees in the front regularily. 

I never experienced or heared of queens be affected by oxalic acid.


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## camero7 (Sep 21, 2009)

David LaFerney said:


> I've used it both when hives had brood and when they didn't and have never been able to detect any negative effects at all.


I've had the same results


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## beekuk (Dec 31, 2008)

David LaFerney said:


> I've used it both when hives had brood and when they didn't and have never been able to detect any negative effects at all.


And the same here.


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## Daniel Y (Sep 12, 2011)

Who cares, the stuff works.


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## snl (Nov 20, 2009)

deknow said:


> Is this really a factual statement? In all cases?
> 
> This is marketing copy to sell a product to Beesource readers (in the sponsors and vendors forum). Making claims that simply aren't true to sell the product is crossing a line that shouldn't be crossed. deknow


Dean, perhaps you should spend more time researching OAV (so as to not look so foolish) prior to posting. From my own experience and from the experiences of many others here in the US, on BeeSource and around the world, OAV does NOT harm the brood or queen.


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## Robbin (May 26, 2013)

Daniel Y said:


> Who cares, the stuff works.


Bingo, we have a winner...


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## beemandan (Dec 5, 2005)

Is it just me....or does it seem like this dead horse has been thoroughly beaten already?


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## snl (Nov 20, 2009)

beemandan said:


> does it seem like this dead horse has been thoroughly beaten already?


Dean (BS member Deknow) brought in a new horse to beat.......!


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## beemandan (Dec 5, 2005)

I find relentless product promotion veiled as innocent thread posts equally annoying.....and would be happy to see that dead horse buried as well.


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## dadandsonsbees (Jan 25, 2012)

That horse is now dog food. I have also tried both and found no ill effects.


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## deknow (Jul 17, 2006)

Do the manufacturers of Thessaly devices make such claims?


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## Jim 134 (Dec 1, 2007)

You do realize that you use this product (Oxalic Acid) off label :s This not approved to be used in beehives in the USA and yes I do know is in the food chain already (Oxalic Acid). Remember one thing the chemical companies will tell you that the label is the law.






BEE HAPPY Jim 134


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## beemandan (Dec 5, 2005)

dadandsonsbees said:


> That horse is now dog food. I have also tried both and found no ill effects.


You've tried horse and dog food? I find it hard to imagine no ill effects.


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## beemandan (Dec 5, 2005)

deknow said:


> Do the manufacturers of Thessaly devices make such claims?


Don't get me started Dean....next up....publishers who don't do any due diligence before printing.


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## beemandan (Dec 5, 2005)

My apologies folks....I'm in a foul mood today....without any real excuse.


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## deknow (Jul 17, 2006)

Dan, I've always been willing to discuss issues anyone has with what I've written online and in our book.

SNL, is this email that just came to my inbox from you?


> Dean,
> You are a small, small, little man……….
> *
> Larry


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## VanIslander (Aug 19, 2013)

Dean, your mailbox is full -- not accepting new mail.


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## shinbone (Jul 5, 2011)

"_Is this really a factual statement? In all cases?_" Is anything always true absolutely 100% of the time?


I used vaporized OA on 11 hives at the end of last season and have not seen any negative effects to the bees or queens. On the other hand, the OA killed a huge number of mites.


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## snl (Nov 20, 2009)

shinbone said:


> Is anything always true absolutely 100% of the time?


Only in mathematics! 2+2 will ALWAYS equal 4! :thumbsup:


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