# OAV and Brood damage



## ffrtsaxk (Jul 17, 2017)

I did an OAV treatment on an observation hive on August 26th. There was some brood present: both capped and uncapped. I did not see any brood die off. I have, however, seen them pull a limited number of drone pupae that had been uncapped when I did an OAV treatment. I think they were probably the drone brood that was directly over the vaporizer when I treated. Notice the white film over the eyes and antennae in the picture. From what I saw in the observation hive, the only react to the OAV when it contacts their eyes and antennae and does not seem to irritate any other part of the bee. Most pupae would be protected since they are capped. But, the eyes and antennae of an uncapped pupa would not be protected and they would be unable to clean themselves off and thus might suffer some damage if directly over the vaporizer where large amounts of oxalic acid could accumulate on them.


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## johno (Dec 4, 2011)

I wonder who the expert could be, I have treated my bees exclusively with OAV and have never seen any bee mortality except when I was using a pan type of vaporizer when I fried a few bees. I have treated my observation hive many times with a full 2 grams of OA over 6 medium frame and all I saw was dead mites no bees or brood. But never mind the experts will tell you that Oav does not work with hives that have brood as you only kill phoretic mites, that you make succesive treatments does not enter into the equation and that my losses over the years are never more than 10% mostly due to queen loss and starvation does not seem to matter at all.


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## Mike Gillmore (Feb 25, 2006)

dddillon said:


> It was not clear if he was referring to dribble, or vaporization, since he said the best method when they are not in cluster is the dribble method, and while in cluster is to use a vaporizer.
> 
> Don


I think it might actually be the opposite. OAV should be administered when the cluster is loose. Dribble is usually used during the late fall/early winter months when the cluster is a little tighter and the colony is broodless, or near broodless. Multiple dribble treatments can be rough on brood. But in my experience over the past 14 years OAV has never caused any brood issues.


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## JWPalmer (May 1, 2017)

This same person also stated the the levels of formic acid in the honey spike after treatment and that honey should not be harvested for several months after a formic acid treatment. ThIs is the first I have heard this part mentioned, although I have never actually read the full instructions for the use of MAQS or Formic Pro since I dont use either.


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## Mike Gillmore (Feb 25, 2006)

> Formic acid is an organic acid that naturally occurs in honey. _Formic Pro_ controls the vapour release of formic acid throughout the treatment period. By the end of treatment, formic acid levels in the hive reflect what naturally occurs in honey, when applied as per label.


http://nodglobal.com/frequently-asked-questions-formic-pro/

Based on this it doesn't sound like a waiting period is needed following treatment. Nobody is perfect, but it sounds like this speaker might want to take a refresher course on mite treatments.


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## Bee Arthur (Mar 21, 2015)

Mike Gillmore said:


> http://nodglobal.com/frequently-asked-questions-formic-pro/
> 
> Based on this it doesn't sound like a waiting period is needed following treatment. Nobody is perfect, but it sounds like this speaker might want to take a refresher course on mite treatments.


And we all need to be a skeptic of anyone flaunting credentials like "Certified Master Bee Keeper." Beekeepers should be measured by their success in the bee yard, not by some certificate they picked up after memorizing the answers to a multiple choice test.


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## Andhors (Dec 7, 2018)

Isn’t the objective to COAT bees and hive surfaces? Whether dribble or vapor you are introducing OA which will contact the bees and mites for several days. With that in mind I doubt it matters whether the bees are balled or not.


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## Mike Gillmore (Feb 25, 2006)

If you have a very tight cluster when applying OAV some of the bees deeper inside the cluster might not be coated with the crystals. With a tight shell of bees surrounding the cluster the vapor might not reach some of the bees within. That's why it's best to treat with OAV when the cluster is relatively loose so more bees have direct exposure during treatment. 

Dribble can be applied to a fairly condensed cluster and the liquid will be dispersed among the bees as it migrates downward through the cluster.

For either method the main goal is to coat the "bees", not necessarily all the inner hive surfaces.


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## Simple Harmony Farms (Mar 22, 2018)

dddillon said:


> At a local beek meeting last night, the speaker (Certified Master Bee Keeper) said that use of OAV while brood was present can kill the brood.
> 
> I have never heard of this, and don't really see this myself.
> 
> ...


Absolutely untrue. Using the OxaVap vaporizer greatly improved the health of my apiary and does not kill brood. 
I tried several in hive mite treatments with no success, as my loses stayed that same from season to season.
I am not saying brood dies from these mite strip treatments, I do know for certain they disrupted my brood nest since the bees steered clear of the immediate area where these strips were placed.
I don't know why you would "dribble" when you can vaporize. I have vapor escaping fron cracks from the bottom to the top of the hives. I don't see how coverage could be any more thorough.
On a side note, I am participating in the Beeinformed Sentinel Colony program which monitors my mite count, among other things. They provide me with an accurate, scientific mite count and I can say with out a shred of doubt, the Oxalic acid vaporizer does reduce the mite counts. I would encourage everyone to participate in this study for at least 6 months. It is an eye opener. No guesswork. Be scientist just may know more than we do. Who would have figured. :scratch:https://beeinformed.org/programs/sentinel/
(Full disclosure, I do know Larry with OxaVap. I do believe in and use his product and would not mention it otherwise.)


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## psm1212 (Feb 9, 2016)

Below is an article by Randy Oliver that discusses Oxalic Acid DRIBBLE. If you scroll about half way down there is a segment "Does it Harm the Bees." In this section, Randy names a few studies on this issue. Remember though, he is talking about a DRIBBLE application and not an OAV application. I think a lot of people are conflating the two types of treatments and their separate effects on bees.

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

Also, Jerry Hayes used to insist in his monthly column in ABJ that OAV treatments were hard on bees. He continually got called out on it by beekeepers asking where he got his information. The only thing I remember him saying was something to the effect of "Well, that is what I am hearing from beekeepers."

In my experience, after hundreds of OAV applications, I have never noticed any ill effects on my bees from OAV treatments. Before the ProVap, I would periodically dry roast a bee or two in my Varrox pan. I also have a lot of blackened circles on the bottoms of some old frames, so I am sure I scorched a few brood cells.


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## JoshuaW (Feb 2, 2015)

I use a ProVap and have not seen any brood damage at all, either; nor did I see any brood damage with a pan-type.

I've heard of a segment of beekeepers using an insect fogger to apply oxalic acid, and some receipes call for dissolving the oxalic in alcohol. Even at a very small dose, I would expect alcohol to dry out open larvae, thus damaging brood...


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## crofter (May 5, 2011)

Alcohol can be used to euthanize a colony so it would not be surprising to see brood damage if it was part of the scenario where brood was affected. OA dribble has been grossly overdosed also due to math errors in making up the solution. 

Operator error?


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## msl (Sep 6, 2016)

JWPalmer said:


> This same person also stated the the levels of formic acid in the honey spike after treatment and that honey should not be harvested for several months after a formic acid treatment. ThIs is the first I have heard this part mentioned,


I cant place it(sorry 3 hours of sleep in the last 36...It haunt season), but some were there was a study showing FA contaminated the honey more the OA, penetrating the cappings and all that… 3 hours of sleep in the last 36



Simple Harmony Farms said:


> I don't know why you would "dribble" when you can vaporize.


faster, cheaper, 3x+ longer action time in the hive, safer for the user, don't have to haul a battery ... the list goes on... don't get me wrong, I built a band heater vap and bought a full face mask. But I am in the burbs.. new beekeep mite bomb central. I had one 8f fill a deep of wet combs I put on for them to clean, no flow. The yards got dribble, need the longer action time to knock back the hitchhikers the robbers bring home.



crofter said:


> OA dribble has been grossly overdosed also due to math errors in making up the solution.
> Operator error?


Yep, I just hurd a story about a new beekeek this year that mis understood metric and did 500ml per package… Word is they bolth lived…


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## 123989 (Jul 30, 2018)

I cant place it(sorry 3 hours of sleep in the last 36...It haunt season), but some were there was a study showing FA contaminated the honey more the OA, penetrating the cappings and all that… 3 hours of sleep in the last 36

How can you contaminate honey with something that is already present in it. I think you have it backwards. According to everything I read at the end of the treatment period FA is back to levels normally found in honey.


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## msl (Sep 6, 2016)

> How can you contaminate honey with something that is already present in it


There is lead in honey as well, would it be ok to seal my jars with led foil? 



> According to everything I read at the end of the treatment period FA is back to levels normally found in honey.


expand your reading 


> Formic acid and oxalic acid field trials for control of Varroa destructor were carried out in autumn according to the Swiss prescriptions during three successive years in different apiaries in Switzerland. The following parameters were determined in honey that was harvested the year after treatment: formic acid, oxalic acid and free acidity. The following range of values were found in honeys of untreated colonies: formic acid, from 17 to 284 mg/kg, n = 34; oxalic acid, from 11 to 119 mg/kg, n = 33. There was a small, but unproblematic increase in formic acid levels in comparison to the levels in the controls; average: 46 mg/kg, maximum: 139 mg/kg. No increase in formic acid was found with increasing number of treatment years. If emergency formic acid treatments were carried out in spring, the residue levels were much higher: average increase of 193 mg/kg, maximum 417 mg/kg. The oxalic acid content remained unchanged, even after two successive treatments during the same autumn.


Bogdanov EtAL 2002
a spring treatment causes a large spike in FA levels, a 567% increase.... Summer Tx would likely be much higher..
simple answer is very few are mixing down FA and doing butcher pads, they buy the premade product, so some one makes $$ so "research" is done and payed for for suppers on approval.

What we keeping seeing is people reading that fall/winter treatment with organic acids has no impact on the next years harvest, and it hits the internet, then the game of telephone happens and it becomes it dosn't get into the honey so its ok to treat close to harvest time.


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## ifixoldhouses (Feb 27, 2019)

Bee Arthur said:


> And we all need to be a skeptic of anyone flaunting credentials like "Certified Master Bee Keeper." Beekeepers should be measured by their success in the bee yard, not by some certificate they picked up after memorizing the answers to a multiple choice test.


There's alot more to it than that I had to pass a big exam, and they came to my bee yard to watch me work the bees, just for the certified. Journeyman, masters have to do all this community service, run bee schools, volunteer at the zoo, fair, pass one hell of a test, and a practical test. In my bee club of 100 people, only me and 2-3 others are certified.


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## Mike Gillmore (Feb 25, 2006)

> No increase in formic acid was found with increasing number of treatment years. If emergency formic acid treatments were carried out in spring, the residue levels were much higher: average increase of 193 mg/kg, maximum 417 mg/kg.


That's interesting. 
When was honey sampled on the hives that had spring treatments. Immediately following the treatment, or later in the year at the same time they performed their regular annual testing?


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## crofter (May 5, 2011)

Mike Gillmore said:


> That's interesting.
> When was honey sampled on the hives that had spring treatments. Immediately following the treatment, or later in the year at the same time they performed their regular annual testing?


Yes, and a few other questions, like was that a representative sample of the total honey in the colony or just a surface dip. The figure quoting a 500% increase can be confusing because that increase may be upon a functionally insignificant amount anyway. 

Either we have been getting snowed by results wishing to sweep things under the carpet, or we are now being snowed by alarmist rhetoric. 

I am not suggesting MSL is cooking the books; I merely suggest that some data may have been taken out of context somewhere, with or without agenda.


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## msl (Sep 6, 2016)

Mike Gillmore said:


> That's interesting.
> When was honey sampled on the hives that had spring treatments. Immediately following the treatment, or later in the year at the same time they performed their regular annual testing?





crofter said:


> Yes, and a few other questions,





> I merely suggest that some data may have been taken out of context somewhere, with or without agenda


channel your goggle fu "Bogdanov EtAL 2002 bees formic acid" and its the 1st hit
https://pdfs.semanticscholar.org/eea2/566024bdc5602b2be61708acda659d4e9751.pdf

as crofter notes its important to get the full contex..


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## crofter (May 5, 2011)

On looking through the above link to the research it appears their data collection and control procedures were very objective. I was surprised at the much greater honey uptake of Formic acid compared to oxalic. There does not seem to be any sensational claims of the acid uptakes to be any safety hazard but formic acid levels can come within the range of taste detectable in some less common conditions.

If both formic and oxalic acids were not such common components of honey, the specter of their uptake would be considered outrageous.


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## Michael Bush (Aug 2, 2002)

When I was using OAV I never saw any damage unless I purposefully did an overdose. The brood, with a normal dose, was fine.


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