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Cameron Jack and Jamie Ellis have published a new study. Seems to be a follow up of the January 2020 Study they published regarding OAV and Brood Breaks. This one tested various dosages of OA when vaporized. No free access to the full article that I can find, but the summary is interesting:

Oxalic acid (OA) is a natural compound that has been used to control the honey bee (Apis mellifera) pest Varroa destructor. One method of OA application gaining popularity among beekeepers in the US involves vaporizing OA crystals with heat inside a closed hive. Herein, we tested different doses of OA applied via vaporization to determine the most effective amount of OA needed to reduce V. destructor populations below that of the negative controls. Forty experimental colonies were assigned to one of four treatment groups, with ten colonies composing each group. The four treatments were: (1) 1 g OA, (2) 2 g OA, (3) 4 g OA and (4) no OA (negative control). The OA was applied via vaporization once per week for three weeks. V. destructor infestation rate and colony strength assessments were estimated before, during, and after treatment applications. Colonies in the 4 g OA treatment group had significantly lower infestation rates than did those in the untreated control and 1 g OA treatment groups, but not those in the 2 g OA treatment group. The infestation rate of colonies treated three times with 1 g OA, which is the current legal limit for OA vaporization in the US, was not significantly different from that of colonies in the negative control or 2 g OA treatment groups. Colonies receiving the highest dose of OA were generally healthier than those treated at lower OA doses. Our results may lead to improved efficacy of OA vaporization, thus aiding beekeepers in their efforts to control V. destructor.

https://doi.org/10.1080/00218839.2021.1877447
 

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I wish they gave a little more info on the dribble with glycerin; that seems good also.
 
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Interesting. No bad side effects on the colonies after 4 oz. of OA? Hmmm 🤔 I guess after a couple more decades of treatments if they don’t grow extra legs, antennae, and a couple more heads each, we will know about the side effects for certain. Hopefully we won’t grow any additional bits from eating honey.🤣
 

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Interesting. No bad side effects on the colonies after 4 oz. of OA? Hmmm 🤔 I guess after a couple more decades of treatments if they don’t grow extra legs, antennae, and a couple more heads each, we will know about the side effects for certain. Hopefully we won’t grow any additional bits from eating honey.🤣
Uh, that would be 4 GRAMS of OA, not ounces. Not to say exactly why I know this, but there are 28 grams in an ounce. I have been treating my double deep hives with 3.5 grams for the past three years.
 

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Uh, that would be 4 GRAMS of OA, not ounces. Not to say exactly why I know this, but there are 28 grams in an ounce. I have been treating my double deep hives with 3.5 grams for the past three years.
Thank you for the correction JW. You are absolutely right about the measurement unit. My bad. I am obviously already suffering from unwanted side effects of something.😲🤭
 

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I am scratching my head
Colonies in the 4 g OA treatment group had significantly lower infestation rates than did those in the untreated control and 1 g OA treatment groups,
but not those in the 2 g OA treatment group.
The infestation rate of colonies treated three times with 1 g OA, which is the current legal limit for OA vaporization in the US, was not significantly different from that of colonies in the negative control or 2 g OA treatment group

no difference between 2 and 4 grams
no difference between 1 gram and nothing
no difference between 1 gram and 2 grams
but somehow a difference between 4 and 1 but not 2 even thow 1 and 2 were the same? and 1 was the same as none so we have been wasting are time treating with one yet some how we killed mites and our hives are alive and those who didn't use one had their hives die?

Maybe the data set will make sense, when it comes out for behind the paywall, but that abstract hurts my brain

we knew jack was playing his cards close on the doses form the last publication.. guess he had another piece to get published
 

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The data is what the data is.
I am a little confused by the "current limit on 1g. per hive " since the approved label says 2 grams.
The requested label change that hopefully will be approved after comment period closes end of April also has dosage for vaporization at 2 grams per hive.
Lastly as much as this work is being done in Florida there was no discussion of drift and mite influx and it's possible effect on the results.
 

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JW, I've been using 3 grams for a while where I had double deeps. I haven't noticed any negative affects on the bees or larvae. I think I will increase it a little. Are you doing a wash or sticky board count along the way?
 

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Randy Oliver literally tried to treat colonies to death with Oxalic vapor and could not establish that he did any damage to the colony treating over and over again! I think we know what we need to. Now that it is a legal treatment we can just do the humane and right thing to do. Move on!
 

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I am a little confused by the "current limit on 1g. per hive " since the approved label says 2 grams.
The label reads one per brood chamber. (and no supers)....e 2 per dubble deep brood box, 3 pre 3 deep brood and 1 for one
my understanding from other sources is theses were single deep hives, so one gram being the legal dose

I wonder if a pan heater designed for 2 g max, as used can handle a 4g dose without boiling over and losing OA
it also begs the question why such antiquated tech was used....what Industry stakeholders use such things?
 

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I understand the label. The summary is the confusing part - if dosage was per hive as stated or per box.
Sounds like per hive - which would make the dosage at label, twice label, four times label and no treatment control if all colonies were equalized at one box.
If equalized at 2 boxes different conclusion.
Just not clear from the summary.
 

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JW, I've been using 3 grams for a while where I had double deeps. I haven't noticed any negative affects on the bees or larvae. I think I will increase it a little. Are you doing a wash or sticky board count along the way?
Sticky board under my SBB. Pull after three days and see what has fallen. Some hives have just a few, one hive last autumn covered the board. All the strong hives have made it through winter.
 
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