# OA article very much worth a read...



## Nugget Shooter (Mar 28, 2016)

This is interesting and educational if you have not seen it yet.... http://www.sussex.ac.uk/broadcast/read/33537


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## cervus (May 8, 2016)

Interesting article. Thanks for posting. I see they used 2 1/4 grams OA/colony. We (U.S.) have been "directed" to use 2 grams/colony. Just wondering if U.S beeks are incrementally underdosing and if it even matters. Just thinking out loud...

_"All three methods could give high varroa mortality, c. 93–95%, using 2.25 g OA per colony."

"The time taken to apply 2.25 g of OA via sublimation, which we consider to be a recommendable dose, is under three minutes per colony."_


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## kerryq (Jan 27, 2014)

cervus said:


> Interesting article. Thanks for posting. I see they used 2 1/4 grams OA/colony. We (U.S.) have been "directed" to use 2 grams/colony. Just wondering if U.S beeks are incrementally underdosing and if it even matters. Just thinking out loud...
> 
> _"All three methods could give high varroa mortality, c. 93–95%, using 2.25 g OA per colony."
> 
> "The time taken to apply 2.25 g of OA via sublimation, which we consider to be a recommendable dose, is under three minutes per colony."_


Maybe Larry (snl) can chime in on this??


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## snl (Nov 20, 2009)

I've read that article. The EPA and Canadians all say one gram of OA. I've used one gram and it has worked well. I'm sure that that on many occasions since that article (when my measuring was not so precise) that an extra quarter gram made it's way into the vap.......


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## enjambres (Jun 30, 2013)

Isn't the British National standard box larger than our Langs? 

Enj.


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## snl (Nov 20, 2009)

I like the following from the article:

Professor Francis Ratnieks, head of LASI, says that beekeepers should cease using the other two methods ("trickling" and "spraying", in which a solution of oxalic acid is used) as they are harmful to the bees and less effective at killing Varroa. 


Professor Ratnieks says: “It is almost too good to be true that sublimation, the best method for killing Varroa with oxalic acid, also has no harmful effects on the bees, and is the quickest to apply. 


“Beekeepers should only use the sublimation method. If they apply oxalic acid in this way, they can be confident that it will kill most of the mites and will not harm the bees.”


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## Rader Sidetrack (Nov 30, 2011)

enjambres said:


> Isn't the British National standard box larger than our Langs?


Yes, the British National deep boxes are slightly larger than Dadant style deeps. By my calculation, British National internal volume is 43.5 liters, compared to 42.7 liters for a Dadant deep.

British National specifications: http://www.beekeeping.org.uk/is_national_hive.pdf


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## cervus (May 8, 2016)

enjambres said:


> Isn't the British National standard box larger than our Langs?
> 
> Enj.





Rader Sidetrack said:


> Yes, the British National deep boxes are slightly larger than Dadant style deeps. By my calculation, British National internal volume is 43.5 liters, compared to 42.7 liters for a Dadant deep.
> 
> British National specifications: http://www.beekeeping.org.uk/is_national_hive.pdf


There you go. .010 gram/liter difference. That's equivalent to the difference between a level teaspoon and a heaping teaspoon.


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## Rusty Hills Farm (Mar 24, 2010)

snl said:


> I like the following from the article:
> 
> Professor Francis Ratnieks, head of LASI, says that beekeepers should cease using the other two methods ("trickling" and "spraying", in which a solution of oxalic acid is used) as they are harmful to the bees and less effective at killing Varroa.
> 
> ...


This guy really ticks me off! OAV works great BUT it *CAN* be dangerous to careless beekeepers who do not take the risk to their lungs seriously. OAD is only a hair less effective HOWEVER it poses absolutely *NO* danger to the beekeeper's lungs. Yes, not killing bees is important. However, not killing BEEKEEPERS is even more important. Somehow professor-types always seem to overlook THAT little detail.

ARRRGGGHH!


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## Nugget Shooter (Mar 28, 2016)

Sadly these days though there are plenty of folks that will use just about anything irresponsibly and get injured from fishing rods to cars to OAV. It is not the OAV hurting the beekeeper that is the issue, it is the beekeeper himself that is the issue if one fails to take proper steps to stay safe. Educating folks in the use of OAV is helpful, but there will always be folks that do it their way and not wear a mask I guess.


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## Rusty Hills Farm (Mar 24, 2010)

I'm not a professor of anything and I only have a few hives, but I did my own little test this summer (details on my website). I used 5 hives and treated by dribbling on August 1, 8, and 15. Lost no brood, no queens, suffered no damage at all to my bees or me...but it sure killed a lot of mites! OAD works too and the beekeeper doesn't need a bunch of equipment to do it. 

I think it is very irresponsible to suggest that OAV is the ONLY effective way to kill mites. Don't misunderstand me. I think OAV is great and effective--just not the *only* great and effective way to kill mites. OAD works too, and very effectively, so folks who cannot afford the wand or have other reasons not to want to use the wand, can use OAD and have excellent results, too. 

JMO 

Rusty


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## LeifLiberty (Sep 23, 2014)

What is OAD? I could not find it in the glossary.


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## cervus (May 8, 2016)

LeifLiberty said:


> What is OAD? I could not find it in the glossary.


Oxalic acid dribble vs. oxalic acid vaporization.


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## LeifLiberty (Sep 23, 2014)

So basically add Oxalic Acid to heavy syrup and pour it on the brood nest? Like 1.2 oz of Oxalic Acid to 32 oz of HS?


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## Rader Sidetrack (Nov 30, 2011)

See this page from Randy Oliver for more on the oxalic acid 'dribble' method:

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


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## crofter (May 5, 2011)

LeifLiberty said:


> So basically add Oxalic Acid to heavy syrup and pour it on the brood nest? Like 1.2 oz of Oxalic Acid to 32 oz of HS?


(I think if you look at the mixing directions the sugar solution is actually a weak solution not a heavy syrup.)

Edit: My apologies; I see mixtures recommended from 30 to 60% sugar with the stronger considered more effective.


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## LeifLiberty (Sep 23, 2014)

I wonder if this stuff would eliminate SHB at the same time?


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## cervus (May 8, 2016)

LeifLiberty said:


> I wonder if this stuff would eliminate SHB at the same time?


 No. If only we could be so lucky...


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## snl (Nov 20, 2009)

LeifLiberty said:


> I wonder if this stuff would eliminate SHB at the same time?


No........ wish it did. But killing mites with no harm to brood, bees or queen and no contamination of the comb is good enough for me.


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## Rusty Hills Farm (Mar 24, 2010)

LeifLiberty said:


> So basically add Oxalic Acid to heavy syrup and pour it on the brood nest? Like 1.2 oz of Oxalic Acid to 32 oz of HS?


The formula I use is 1.2 oz. OA, 16 oz. water, 16 oz. sugar. These are by weight, not volume. Makes approximately 24 oz. of solution and treats 10-12 hives. Using a syringe, I squirt 5 mL per seam of bees in the brood boxes. That is approximately 50 mL per hive. I do not separate the brood boxes but I do remove the supers while treating and return them to the hive before I close it up. I had a pretty severe infestation at the start of the test and pretty clean mite counts at the end. 

HTH

Rusty


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## psm1212 (Feb 9, 2016)

Rusty Hills Farm said:


> OAD works too, and very effectively, so folks who cannot afford the wand or have other reasons not to want to use the wand, can use OAD and have excellent results, too.


I think Randy Oliver's work has unequivocally proven this point for me.


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## Boglehead (Feb 16, 2009)

Has anyone used OA vapor under screened bottom board to treat hives? I have recently installed mouse-guards on my colonies and like any shortcut I can find.

Thanks


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