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Inclement weather has prevented me from doing OA vape 5 days apart, it's now been 7 days since my treatment.

Questions.

1. Has anyone noticed a difference between 3 applications 7 days apart, or 4 or 5 applications 5 days apart?

2. Anyone notice a difference when vaping different quantities of OA? For example, if I treat with 2 grams, and then 1.5 grams - is it going to make a difference?

3. What if I don't find any mites when doing a mite count, do I skip that hive?

4. I've read that in Europe it's common to leave honey supers on the hive during OA vaporization. Does this mean that OA vaporization doesn't contaminate honey?
 

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This is a good article by Rusty Burlew discussing the timing of OAV treatments:

https://honeybeesuite.com/using-oxalic-acid-vaporization-when-brood-is-present/

With regard to honey contamination, this is a common topic on this board. OA that is properly labeled for treatment of varroa mite, states under its Use Restriction section that OA cannot be used "when honey supers are in place to prevent contamination of marketable honey." So, it can not legally be used with honey supers "in place."

Whether OAV actually contaminates honey, and whether honey "contaminated" by OAV has any harmful effects for humans that consume it, are matters of some debate.
 

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This is a good article by Rusty Burlew discussing the timing of OAV treatments:

https://honeybeesuite.com/using-oxalic-acid-vaporization-when-brood-is-present/

With regard to honey contamination, this is a common topic on this board. OA that is properly labeled for treatment of varroa mite, states under its Use Restriction section that OA cannot be used "when honey supers are in place to prevent contamination of marketable honey." So, it can not legally be used with honey supers "in place."

Whether OAV actually contaminates honey, and whether honey "contaminated" by OAV has any harmful effects for humans that consume it, are matters of some debate.
Do you have any links to this debate?

From what I've read all over Europe OA vaporization is OK to perform with honey supers on the hive.
 

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Do you have any links to this debate?

The search feature on this forum is lacking. I found this past discussion. I know there are many others.

https://www.beesource.com/forums/showthread.php?354667-Oxalic-Acid-and-honey&highlight=Oxalic+Honey


From what I've read all over Europe OA vaporization is OK to perform with honey supers on the hive.

I don't disagree with you. Your original question was "Does this mean that OA does not contaminate honey?" I don't have a definitive answer to that question. Partly, because we need to define what "contaminate" means.

To me, a purely technical reading would be that "contaminate" would include ANY increase in OA levels of honey at ANY time during the honey-making process, from nectar to dried and capped honey. If this is what you mean, then I think the answer is YES, there can be increased OA levels to exposed nectar/honey. How quickly those elevated levels degrade back to the normal range of OA content of honey has been studied some, but I believe very little.

Also to me, the practical reading of "contaminate" would be whether these increased levels create a hazard for human consumption. Common sense tells me that -- at least in the doses and frequency that I treat -- it would be virtually impossible to contaminate honey with my OAV practices to the point to be harmful for human consumption. However, common sense is not scientific evidence.

All we know is what the label, and therefore the law, tells us: Don't use it with honey supers in place.

I would really like to start a kickstarter campaign to fund a local bee college (I am surrounded by great bee colleges at Auburn University, University of Georgia and University of Florida) to do an EPA/FDA registered study to demonstrate once and for all that OAV applications with honey supers in place do not elevate OA content of honey to harmful levels. This would be a great service to beekeepers.
nm
 

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Logic says the uptake would be higher in uncapped honey, pretty low in capped.
 

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As Oxalic Acid is a natural component of honey, and found there in variable concentrations - how exactly would you go about identifying whether 'contamination' had actually taken place ?

Also - so-called Oxalic Acid vapour is actually a fine micro-crystalline dust, which - like all dusts - tends to settle upon horizontal surfaces in preference to vertical surfaces. I would suggest therefore that any increase in the Oxalic Acid content of honey following VOA treatment will be both minimal and undetectable.
LJ
 

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As Oxalic Acid is a natural component of honey, and found there in variable concentrations - how exactly would you go about identifying whether 'contamination' had actually taken place ? I am thinking a study where an apiary is established with limited variations in forage producing similar frames of honey. You would have a control group that does not get treated and several that are treated with various amounts of OAV and at varying intervals. Then you would uncap and test the honey from all groups at n days from last treatment, and n+15 days, and n+30, n+90, etc. This would establish the naturally occurring level of OA, how OA content is affected by various doses and frequencies of OAV treatment and how quickly/slowly OA degrades in honey over time.

Also - so-called Oxalic Acid vapour is actually a fine micro-crystalline dust, which - like all dusts - tends to settle upon horizontal surfaces in preference to vertical surfaces. I would suggest therefore that any increase in the Oxalic Acid content of honey following VOA treatment will be both minimal and undetectable. This is my suspicion as well. I think the differences, if detected, will be negligible. If we establish this for our EPA, then we can legally treat our hives with OAV throughout the nectar flow as we need to based on mite monitoring.
nm
 

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It would also be an interesting experiment to actually sprinkle some of these fine crystals onto some open brood while a frame is held horizontally to see if there is any effect on the brood. If there is any effect you could be pretty sure that those fine crystals do not get into the horizontal cells. As far as the EPA is concerned I fell one would be wasting ones time unless a large sum of money changed hands.
 

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In the comments the Europeans kept referencing dribbling AO by syringe. What is this method?
Dribbling is a method of dosing mites with OA which pre-dates vapourisation, and is still favoured by those who either do not have access to more expensive VOA equipment, or by those who's focus is more upon personal safety considerations.

The technique involves applying a mixture of OA and sugar-syrup - with a syringe - as uniformly as possible over bees working between frames.

I've never used this technique for several reasons: firstly it means the full opening of a beehive for access (both time-consuming and disruptive); secondly, I've always been concerned that the bees would ingest the OA whilst licking-off the sugar syrup; thirdly, I've never been able to figure out how a uniform distribution of OA throughout the colony occurs; and lastly, the figures for efficiency are not particularly impressive (unlike VOA).
LJ
 

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I am thinking a study where an apiary is established with limited variations in forage producing similar frames of honey. You would have a control group that does not get treated and several that are treated with various amounts of OAV and at varying intervals. ...
Yes, that would be a good basis for an experiment - a crop similar to Canola (Oil Seed Rape) perhaps, which the bees go wild for, and (afaik) ignore other sources of nectar whilst that crop is in bloom. I think that would work ok, and checks could presumably be made for contamination of honey and brood at the same time ?
LJ

(now to find the funding ...)
 

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Inclement weather has prevented me from doing OA vape 5 days apart, it's now been 7 days since my treatment.
Back to this real quick.

4 Treatments on a 5 day schedule is probably the best regimen. Some, like myself, are not able to treat on a 5 day schedule due to conflicting work schedules. I have no choice but to treat on weekends on a 7 day schedule. I've done this for many years with excellent results. If the mite load is high when starting sometimes I'll add a 4th treatment for a little extra insurance.

I always use the higher dose, a little extra will not hurt the bees and I want to insure good coverage.

Everyone has their own preference, but I treat all the hives on a regular schedule regardless of what my mite counts might be telling me. I never fail to see good mite drops after the initial treatments, seems they all need help to one degree or another every year.

In NE PA you might be just a bit early starting your treatment series. Being in a similar region I usually start mid August into September. Be sure to check your hives carefully later in early fall to make sure the mites have not rebounded. If so, you might need to do another series to clean them up.
 

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(now to find the funding ...)
I think it would be a great doctoral thesis/project for a PhD student. Plus, if they got something published, they could easily do the ABF, EAS, HAS speaking tour bringing the good news to all beekeepers in the US. You may even get them an invite to a UK speaking engagement. Newly-minted entomology PhDs otherwise don't get that type of early career exposure.
 

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I have done the three treatments 7 days apart (3/7) and the four treatments five days apart (4/5) schedules and have not noticed any difference. However, I do prefer the 3/7 over the 4/5 because I am basically lazy. When it comes to which one do I believe works better, I prefer the 4/5 treatments schedule and this is the one I usually follow. It all comes down to your beliefs. When a mite hatches out and the cell is uncapped, according to your beliefs, how long is the "phoretic" period? My reading shows it is 5 - 11 days. With the 3/7 schedule, a mite that hatches out may not be phoretic when the treatment is done. If it hatches out the day after you treat and gets under the cappings 5 days later, it will not be exposed "directly" to a treatment. There is some continuing coverage after a treatment is done so that is a factor as well. Regardless of which system you use, some mites will always survive. The goal is to knock them down to a point that they are not a major problem.

In the end, both treatment schedules work just fine. It is all about preference. When I used a wand type vaporizer, it took a long time to treat my hives (about 1 hour) so I did it every 7 days. I now have the Provap and it is a whole lot faster (about 15 minutes) so I do the treatments every 5 days. If I miss a day or two because of scheduling, I don't stress out over it. The real key is to actually do the treatment, not so much the timing.
 

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What do we really know about mites, 5 to 11 days having to be phoretic. Surely the foundress mite does not need time to mature and can go back into the cell of larvae when one of the correct age is found. so the phoretic time of a mature mite could be hours or days until it finds a place to go. I gather that the immature mites need a little time to mature and this will give you the longer period of that mite being phoretic. Are there really any papers written on research in this area or is this also like the mite living off bees heamolymph.
 

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What do we really know about mites, 5 to 11 days having to be phoretic. Surely the foundress mite does not need time to mature and can go back into the cell of larvae when one of the correct age is found. so the phoretic time of a mature mite could be hours or days until it finds a place to go. I gather that the immature mites need a little time to mature and this will give you the longer period of that mite being phoretic. Are there really any papers written on research in this area or is this also like the mite living off bees heamolymph.
These are exactly my concerns. I am also somewhat dubious of the claims that OA remains an active miticide in the hive for hours, even days, after treatment. Some believe it to be only a flash treatment, and only effective for the brief time period that the OA is gasified in the hive. I have been looking for some good research on this issue as well.

All this being said, I am a big fan of OAV and use it in my yards.
 

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The OA is never gasified in the hive, there are only fine particles of OA crystals suspended in the air for a shot period of time, while those particles are suspended they are not harming mites. The mites are harmed when they come into contact with fallen crystals or if they come into contactact with crystals that have come to rest in some place or the other. This could be on the abdomen of the bee or on the surface of the combs or elsewhere in the hive. These crystals will remain there for some period of time, how much time again is speculation as in many other bee related stuff. It would be interesting to get some of this vaporized OA and measure the size of the crystals under a microscope to get an idea of their size as I believe they do no harm to bees as the crystals are too big to got into their sphericals but are none the less small enough to be trapped in the mites hairy spikes and also to create problems with their feet.
 

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The OA is never gasified in the hive, there are only fine particles of OA crystals suspended in the air for a shot period of time, while those particles are suspended they are not harming mites. The mites are harmed when they come into contact with fallen crystals or if they come into contactact with crystals that have come to rest in some place or the other. This could be on the abdomen of the bee or on the surface of the combs or elsewhere in the hive. These crystals will remain there for some period of time, how much time again is speculation as in many other bee related stuff. It would be interesting to get some of this vaporized OA and measure the size of the crystals under a microscope to get an idea of their size as I believe they do no harm to bees as the crystals are too big to got into their sphericals but are none the less small enough to be trapped in the mites hairy spikes and also to create problems with their feet.
If not gasified (or converted to gas), I don't know how we can use the term "sublimated" when discussing the OAV process. As to the bees coming into contact with crystals in the hive after the sublimation/gasification/vaporization???, I don't know that your theory of what is happening has been scientifically proven. I am not saying it is false. I don't know. I just haven't seen the research that supports it. There are some that seem to believe there are no lingering effects of OAV after it has converted from its - to use your term - vaporized state. That it is only a flash treatment, which acts much the same as Formic Acid. Formic does not crystalize in the hive nor is it required to come into direct contact with the mite (at least not contact with the application pads/strips). Formic's mode of action is as a fumigant. Oxalic, when dribbled in sugar syrup, must come into contact with the mite. But I have wondered what the mode of action is for OAV. Is it contact like Apivar and OA dribble, or is it a fumigant, like formic and thymol? I have not seen a scientific paper specifically stating the MOA of OAV.
 
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