# Oxalic acid vaporizer treatment.



## firstpass (Mar 30, 2017)

I am new to beekeeping and would like to know when is best time to treat with the Vaporizer.

Some say do not treat when supers are on others state out doe not matter. Some say to treat on a 21 day cycle. Then some say to treat no more than twice a year. The build up can peak in July but supers are on. Then you want the hive healthy for the winter. This is very confusing to a newbie. Any clarification would be helpful.

The trachea mites when is the best time to treat. Anyone using a menthol treatment or other type of natural type treatment. Any assistance would be appreciated.
I want to take care of the bees and set up a time to treat, I find it interesting and rather confusing at the same time. I like learning about the little creatures but want to help them if I can. I only have the one hive at this time.

If I buy nuts in May should I treat them or leave them alone. Should they have been treated by the place where they are purchased,


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## Rader Sidetrack (Nov 30, 2011)

Oxalic acid vaporization only affects the varroa mites that are _not_ in capped bee brood cells. So, if one is treating when the hive has capped brood, some of the mites are protected by being in the capped brood cells. That is why, when there is brood in the hive, that a series of treatments is recommended. The idea is that the mites that are protected during the first treatment will be exposed when the 2nd treatment occurs, and similarly for the 3rd treatment.

If you are treating during a period of _no brood_ (say as the bees head into winter), then one treatment should suffice as there are no mites protected by capped brood cells (since there is no capped brood). Rather than treating on a schedule, you may be better off to periodically do a mite count and treat when the mite count indicates a problem (i.e. 2%). I'd suggest at least asking your nuc vendor about what treatments they may have done (and when) for the nucs you are getting.

If you choose to treat when honey supers are on the hive, you can temporarily block off the the honey supers by inserting a board between the brood nest and the supers.

Most likely you don't need to treat for tracheal mites, unless you have specific evidence that there is a tracheal mite problem.


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## enjambres (Jun 30, 2013)

I'll add to what Rader Sidetrack said:

When you have brood you need to treat at least three times to catch all the mites as they roll on out of their stay under the cappings. The labeled treatment for OAV is 3 times on seven day intervals, which covers a period of 15 days. Treat on the same day of the week. That is the labeled dosage these days. (And for pesticides "_the label is the Law_.") Some people find an additional treatment the following week is needed.

One way to treat when you have the supers on is this: late in the day before lift the supers off and place a bee-escape board on the hive (make sure you've got it set up to work downwards). Replace the supers for the night. The bees will leave overnight and not be able to get back in. In the morning when you go to treat, lift the supers off again and put a political sign on top of the bee escape board and set the supers back on the stack above the sign. Then do the treatment and leave things as they are for an hour or so. Then take the supers off, plus the political sign and the bee escape board and put the whole stack back together again as it was. The political sign keeps the vapors sealed in the hive away and separate from the supers during and after the treatment while the vapors settle down.

You can treat more than once with OAV, and even more than one series is OK. 

Treating when there is no, or nearly no, brood in the early winter is the most effective time to do it, though that usually isn't enough to keep the numbers low for a whole year. But it still is a critically important thing to do, no matter what else you may need to do. Treating when there is no capped brood because there has been a brood break for some reason is also very effective. Anytime you have that situation it's worthwhile thinking about hitting the colony with a single shot.

All this effort will be somewhat wasted if you are not also monitoring the mite numbers on a regular basis, both before and after the treatment (and that goes for any kind of mite treatment, not just OAV.) I recommend to my students that they do a sugar roll every month, on every colony from April through the end of October. Most also use sticky boards weekly.

The only twice per year recommendation is for OA _dribble_, same chemical, but different application method and to some degree, a different mode of action. It is harder on the the hives than OAV, hence the limited use recommendation.

In order to do OAV you need a special tool and a small (lawn mower size) battery, plus personal protective gear including an *acid gas respirator* and goggles. Ignore any cowboy who says you don't need a mask. You need one, period, and not using one exposes you to significant risk of irreversible respiratory damage. Don't be foolish and try to save the $40-50 the gear will cost. And once you have the mask - _wear it_. Every. Single. Time.

Currently there are almost no reports of tracheal mites in the US. Thank God for that! So no need to treat for them. (Though one mite treatment, formic acid or Mite Away Quick Strips -MAQS - treats for both so that's a reason to switch-up your treatments every now and then. It also kills varroa mites under cappings and can be used with the supers ON. It has a very tight temp range for safe usage and is harder on brood, and in particular queens, than OAV. )

If you've got bees, you've got mites, from the first day you hive them. So don't shilly-shally around thinking you're OK for the first year or you'll be likely to be buying new bees on an annual basis. Decide on a monitoring method, and then get it done on a regular basis. I recommend the Megan Milbrath's Michigan Method of Mite Monitoring which can be learned here: https://pollinators.msu.edu/resources/beekeepers/varroa-mite-monitoring1/

If you have questions on how to do it, I'll be glad to help. I have seen it work as well as alcohol washes which kill the bees each time. Sugar rolls, properly done, do not.

If you stay on top of mite monitoring, and have a treatment program that is effective you'll have much more success and remove a huge amount of the stress and worry from your beekeeping experience.

Enjambres


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## fatshark (Jun 17, 2009)

Are there any studies that unequivocally demonstrate that OA residues are *not* transferred to honey supers when treating in the way suggested? I'm aware of studies that look at OA 'persistence' after dribbling/trickling in the winter, but none that look at the aftermath of vaporising.

Honey already contains a measurable (and often variable) amount of OA. I appreciate that the *clear-isolate-treat* regime suggested minimises direct exposure to the supers, but that doesn't mean it will not get transferred in the week or so after vaporising during which mite drop continues (presumably because OA levels remain damaging for the mite).

We should be aiming to produce a top-quality product and I'd only be confident in using this strategy if the post-treatment residue carry-over was *demonstrated to be insignificant*.

And ... in direct answer to the OP. You *can* treat multiple times with vapor with no ill effects. It's been done on a weekly basis throughout the season by some (when testing for toxicity, not on honey production hives presumably). Secondly, nucs purchased in May can be treated directly (if needed) and then moved to a full hive to be ready for the flow. Thirdly, you should have time after the supers come off to treat again whilst still treating early enough to protect your winter bees from the viruses transmitted by the mites ... unless your flow is unusually late.


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## Delta 21 (Mar 4, 2016)

enjambres said:


> If you've got bees, you've got mites, from the first day you hive them. So don't shilly-shally around thinking you're OK for the first year or you'll be likely to be buying new bees on an annual basis. Decide on a monitoring method, and then get it done on a regular basis. I recommend the Megan Milbrath's Michigan Method of Mite Monitoring which can be learned here: https://pollinators.msu.edu/resources/beekeepers/varroa-mite-monitoring1/
> 
> Enjambres


Thanks for this. I did emergency OAV treatment last fall and and tried to time a broodless treatment around New Years. My next goal is to learn the alcohol wash or sugar roll so I can more effectively monitor things. I only have 3 hives and am using a crackpipe for application but know that a Varrox is in my near future.


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## msl (Sep 6, 2016)

enjambres said:


> When you have brood you need to treat at least three times to catch all the mites as they roll on out of their stay under the cappings. The labeled treatment for OAV is 3 times on seven day intervals, which covers a period of 15 days. Treat on the same day of the week. That is the labeled dosage these days. (And for pesticides "_the label is the Law_.") Some people find an additional treatment the following week is needed.
> 
> One way to treat when you have the supers on


the label is the law and it in NO WAY states 3 treatments 7 days apart! In fact it says to rotate treatments and to avoid treating when there is enough brood to justifies 2-3-4 treatments https://www3.epa.gov/pesticides/chem_search/ppls/091266-00001-20151013.pdf



> USE RESTRICTIONS:
> Oxalic Acid Dihydrate applications are for outdoor use only.
> DO NOT use in enclosed overwintering areas.
> Use only in late fall or early spring when little or no brood is present. Oxalic Acid Dihydrate might damage bee brood. Oxalic Acid Dihydrate will not control Varroa mites in capped brood. *Do not use when honey supers are in place* to prevent contamination of marketable honey


By the letter of the Lable/Law (US) *NO* summer treatments, in fact no treatments with in any range that a super would normally be or is in place 

In short, don't mess a good thing up, rotate your treatments, and use the right one for the right time of year.


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## R_V (Aug 20, 2016)

I have 2 packages that I want to treat with OAV and was looking for procedural thread I remember seeing months ago.
There was info on time of day, outside temps, etc.

Rader Sidetrack put together a good list but I didn't see it there.


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## Rader Sidetrack (Nov 30, 2011)

>> ... want to treat with OAV and was looking for procedural thread I remember seeing months ago.

This, perhaps?
http://www.beesource.com/forums/sho...of-day-to-treat-with-an-oxalic-acid-vaporizer

This OAV thread was created _just before_ the EPA officially registered/approved oxalic acid for varroa control. Its a long thread, with 300+ posts, but it covers many aspects of vaporization:
http://www.beesource.com/forums/sho...alic-Acid-Vaporization-Questions-and-Answers/

.


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## R_V (Aug 20, 2016)

that's not what I wanted to hear.. I'm not a morning person... 

found this though...

https://www.youtube.com/watch?feature=player_detailpage&v=q4WvPNmS7uc#t=1832


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## snl (Nov 20, 2009)

fatshark said:


> Are there any studies that unequivocally demonstrate that OA residues are *not* transferred to honey supers when treating in the way suggested? I'm aware of studies that look at OA 'persistence' after dribbling/trickling in the winter, but none that look at the aftermath of vaporising.


http://www.apidologie.org/articles/apido/pdf/2006/01/M6010.pdf


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## fatshark (Jun 17, 2009)

snl said:


> http://www.apidologie.org/articles/apido/pdf/2006/01/M6010.pdf


I know that paper and it doesn't report OA residues in honey supers directly after treatment. It reports the levels the *following Spring after autumn treatment*. This might be 3-6 months later. 

The key reference paragraph is "_After treating colonies during autumn with the Varrox evaporator (1–5 g oxalic acid dihy- drate crystals/tablets) the oxalic acid content of spring honey was within control limits (Radetzki and Bärmann, 2001; Moosbeckhofer and Baumgartner, 2002)"_. 

My question related to the proposal that it was OK to treat with honey supers on, but simply isolate them on the day of treatment.

It might well be fine ... but I've yet to see evidence that it is.


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## Groundhwg (Jan 28, 2016)

fatshark said:


> My question related to the proposal that it was OK to treat with honey supers on, but simply isolate them on the day of treatment.
> 
> It might well be fine ... but I've yet to see evidence that it is. [/SIZE]


Sort of works both ways; are there any reports, papers, information that OAV treatments leave any harmful or other residue in the honey?


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## snl (Nov 20, 2009)

fatshark said:


> My question related to the proposal that it was OK to treat with honey supers on, but simply isolate them on the day of treatment.


I don't believe you'll find any further evidence or that study and I've searched......... Anecdotal evidence strongly suggests that it's fine. Consider how the vapors quickly form crystals in the hive after vaporization and the bees see that as "junk" and quickly begin to carry it out. In parts of Europe, they actually treat with the supers on and NO barrier.


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## psm1212 (Feb 9, 2016)

Do we have any studies showing hives treated with OAV with honey supers in place render honey that is harmful for humans to consume? What is the maximum level of OA a human can safely consume in a serving of food? We seem to act like this stuff is arsenic and not a common organic acid found in our regular every-day healthy diets.

My understanding is that there is no FDA approval for use of OA with honey supers on because the FDA was not petitioned to approve OA use with honey supers on. Not because there was, or ever has been, a finding that OAV with honey supers on rendered honey that was unsafe for human consumption.


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## Rader Sidetrack (Nov 30, 2011)

Perhaps you mean EPA, not FDA?

It is/was the EPA that manages registration of pesticides and it was the EPA that approved oxalic acid for control of varroa in 2015.


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## psm1212 (Feb 9, 2016)

Rader Sidetrack said:


> Perhaps you mean EPA, not FDA?
> 
> It is/was the EPA that manages registration of pesticides and it was the EPA that approved oxalic acid for control of varroa in 2015.


Yes Rader. My mistake. Thank you


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## cervus (May 8, 2016)

psm1212 said:


> What is the maximum level of OA a human can safely consume in a serving of food?


From the previously quoted paper; _The US Environment Protection Agency concluded that 0.14 mg oxalic acid or oxalate/kg/day over a 24-hour-period represents the allowable
human exposure from all sources (US EPA,1992)._

And this; _Autumn treatment with oxalic acid dihydrate, according to the methods and dosages described, causes no evident increase of natural oxalic acid content in honey, and there is therefore no risk to human health from consuming the honey._

Seems like pretty convincing evidence that the residue issue is really a non-issue.


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## psm1212 (Feb 9, 2016)

cervus said:


> From the previously quoted paper; _The US Environment Protection Agency concluded that 0.14 mg oxalic acid or oxalate/kg/day over a 24-hour-period represents the allowable
> human exposure from all sources (US EPA,1992)._
> 
> And this; _Autumn treatment with oxalic acid dihydrate, according to the methods and dosages described, causes no evident increase of natural oxalic acid content in honey, and there is therefore no risk to human health from consuming the honey._
> ...


There are 750 mg of OA in a 100 gram (3.5 oz) serving of spinach. If I ate 100 grams of Spinach, I have eaten over 5,357 times the amount of oxalic acid that is an allowable human daily exposure according to the EPA? I am having a hard time squaring this. Either I am making a massive math error or we are talking about a very different form of OA.

EDIT: I think I found my error. That is 0.14 mg/ per kg of the consuming human's weight (I think?) So if I weighed 90 kg, the daily allowable consumption of OA would be 12.6 mg. A serving of spinach still sends me WAY OVER that mark, but not 5,357 times over the mark. Only 59.5 times over that mark. The article also states that the estimated daily OA intake of a European diet is 70 to 80 mg, with vegetarians eating up to 600 mg per day.


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## cervus (May 8, 2016)

IMO, the EPA again shows ultra-conservative calculations that barely, if at all, correlate with real life. But that's another story... 

The conclusion I drew from the study is that there are no human health concerns regarding oxalic acid treatments in honey bee hives, period. I'm comfortable with that.

I'm with you, according to the EPA's "guidelines", spinach should be declared a hazardous substance.


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## shinbone (Jul 5, 2011)

cervus said:


> IMO, the EPA again shows ultra-conservative calculations that barely, if at all, correlate with real life. But that's another story...



The EPA is not going to say using a particular chemical on food is safe unless there is a reasonable amount of good quality data that affirmatively supports that conclusion. This is especially true if the chemical in question is not produced by a big corporation with a financial interest at stake and producing its own studies, as is the case with OA.



.


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## SS Auck (May 8, 2015)

If you have ever had starfruit then you have consumed OA.


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## Lightswitch (May 29, 2014)

enjambres said:


> When you have brood you need to treat at least three times to catch all the mites as they roll on out of their stay under the cappings. The labeled treatment for OAV is 3 times on seven day intervals, which covers a period of 15 days. Treat on the same day of the week. That is the labeled dosage these days. (And for pesticides "_the label is the Law_.") Some people find an additional treatment the following week is needed.


I just heard something in the Western Beekeeping Seminar this past winter I can't remember: the Association President mentioned a multi-week OAV treatment that knocked down to the 90 percentile over the course of - I think - four weeks... Anyone could tell me the schedule for that? (I thought he mentioned Michael Bush or Michael Palmer, but I couldn't find anything like that)


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