# How soon oxalic acid kills mites



## Finman (Nov 5, 2004)

.

When we handle mites with oxalic acid and we look how much mites hive have had, it is important to notice that it takes about 2 weeks before results can be seen.

http://www.dave-cushman.net/bee/oxalic.html 

Brent.roberts have made very good table here.
http://www.hhrobertsmachinery.com/private/mites.xls 

So we may notice that mites have died 10 times more after 2 weeks than after one week.

I have not find much evidencies about this issue but so it seems ......

Perizin is a stuff which I used against varroa 1987 first time and I used it some years. I got stuff from Germany. It was not very effective compared with oxalic trickling.


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## brent.roberts (Dec 31, 2005)

I was initially disappointed in the drop rates the day I first treated, but the drop rate continued to rise. 

On the chart Finman linked above, when I treated the second batch of hives, two days after I did the first two hives, the drop rate continued to rise for 3 days. 

I wish I had noted temperatures more carefully at the beginning because temperature and hive activity at this time of year seems to have a big effect on the drop rates.


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## drobbins (Jun 1, 2005)

Brent,

here's a little wild speculation
I wonder if the OA residue in the hive is encouraging hygienic behavior
I wonder if this behavior is more active when the weather is warmer resulting in the results you're seeing (I'm thinking what you call cool in Ontario in November is pretty cool by my standards thus inhibiting grooming behavior)
the mechanism by which OA kills mites doesn't seem to be well understood, so this is just some wild musing on my part as to why you seem to be seeing this correlation between mite drops and temps 

Dave


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## betrbekepn (Aug 7, 2006)

brent.roberts 

>I wish I had noted temperatures more carefully at the beginning because temperature and hive activity at this time of year seems to have a big effect on the drop rates.

Try this. http://www.wunderground.com/cgi-bin/findweather/getForecast?query=Ontario%2C+Canada I couldn't find Caledon but maybe one of these cities are nearby. After you select one go down to (history and almanac) for very detailed weather history info. If this doesn't work you could go to you local library. There you can find newspapers from past dates. Look at the weather section for the date you are looking for.


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## Finman (Nov 5, 2004)

.
When you give oxalic acid gas (--->formic acid) it needs quite a high out temperature. 

But you may use trickling even you have outer temperature under freezing point.


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## brent.roberts (Dec 31, 2005)

Thanks for the wunderground link. I've put the temps on each day. I used Markham which is about 25 miles east of us but most important it is the same distance from Lake Ontario as we are.


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## drobbins (Jun 1, 2005)

Finman,

what do you mean by this

>oxalic acid gas (--->formic acid)

I wouldn't think the conditions would be right to thermally break down oxalic acid into formic acid since the oxalic acid is removed from the heat source immediately once it vaporizes
I've also never heard of the queen problems sometimes reported with formic acid occurring with the use of oxalic acid

can you elaborate?
Dave


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## Jim Fischer (Jan 5, 2001)

> oxalic acid gas (--->formic acid)

Only if _improperly_ heated. 

> I wouldn't think the conditions would be right 
> to thermally break down oxalic acid into formic 
> acid since the oxalic acid is removed from the 
> heat source immediately once it vaporizes

The problem here is vaporizers that are primitive
in the extreme.

The sublimation point of OA is about 157°C, while
the melting point (where it decomposes down to
Formic and carbon monoxide) is about 189.5°C.

The problem is that none of the vaporizers have
any sort of thermostatic control at all. They
can "overshoot" the target temperature, and may
only be at the sublimation temperature on rare
occasions, almost assuring that the OA is 
melted before it is sublimated.

The homemade vaporizers ("crack pipes") are 
clearly a joke in this regard, but the surprise
is that the ones sold for serious money are
little better.


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## BerkeyDavid (Jan 29, 2004)

Jim

Have you tried any commercial vaporizers?

Are there any test results that support your theory?

Having used both the crack pipe and now a commercial one the commercial vaporizer does at least appear to be much more effective.

But I dont' have the tools to measure the temperature that is reached by the vaporizer.

The temperature does rise in the commercial vaporizer. You fill it when it is cool. Then it does heat up gradually. So it must move through the temperature range.

When I was using the crack pipe and having problems I was using a Mapp gas torch initially instead of a propane torch and really had problems, but at th elower range of temps from the propane torch it worked better.

So it seems to me that even if there is no regulation at the top end, if the temperature increase is relatively gradual through the range it ought to work.


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## Jim Fischer (Jan 5, 2001)

> Have you tried any commercial vaporizers?

Yes. I was considering manufacturing one 
that (gasp!) would hive a stable max temp, 
but the product liability implications made 
it a no-go.

> Are there any test results that support your 
> theory?

My word alone should be good enough.
I don't have a "theory", I made repeated 
measurements made with real thermocouples,
so I offered objective fact, rare as it
may be on BeeSource.

> But I dont' have the tools to measure the 
> temperature that is reached by the vaporizer.

Just look at the design of the thing - there
is nothing to limit the temperature.

> So it must move through the temperature range.

Yes, and far too rapidly to allow any significant
amount of OA to sublimate.

> So it seems to me...

Things are often not what they seem.
Very often.


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## BerkeyDavid (Jan 29, 2004)

Jim
Have you published otherwise shared your measurements with thermocouples? If so please refer me to them.

I guess you would admit that your statement above:

<They may only be at the sublimation temperature on rare occasions>

is incorrect. 

In fact they are always at the sublimation temperature, although you claim that they do not remain at that temperature very long.


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## BWrangler (Aug 14, 2002)

Hi Guys,

>Just look at the design of the thing - there
is nothing to limit the temperature....

All of the smarts were left out of the device. But I figured that the smarts should reside in the operator. Running an oxalic evaporator isn't a very good job for an idiot. Gosh, there are measures, matches, poisonous gases, hot metal and the necessity to operate and assess the thing properly :>)

In practice, the old crack pipe was amazingly effective when operated properly, even as primitive as it was. Evaporating oxalic has proved to be more effective than the liquid, in spite of the fact that none of the devices has any temperature limiting mechanism other than the operator.

And it didn't take much training to run one properly, just a few dry runs. The original design was made from brass fittings which had more mass and were more forgiving. I experimented with thinner, copper fittings and they worked, but required more operator skill.

Some crack pipes were made from glass which could be even more forgiving and provide more feedback than the brass.

The real test is in the doing. When operated properly, a fine, white material covers the hive's interior. And that happens most of the time, regardless of the operator's skill. Just what would that stuff be? Is it carbon dioxide or formic? ;>)))

Thinking that the crack pipes were ineffective, now that's a joke! Any oxalic conversion losses have been compensated for by the empirically determined dosage. If a device is designed to more effectively sublimate oxalic, maybe the dosage could be reduced. But that difference might be insignificant compared to the environmental variables, encounter outside the lab, that would require a higher dosage to be effective.

I received some email, concerning the old crack pipe, that concerned me. It indicated some were building and using the crack pipe without reading the material on the page. I think they only looked at the pictures! I no longer recommend using the crack pipe on my web pages for that reason. Dribbling is a safer, cheaper approach for most. And it's certainly more idiot proof than any heated device could be.

Evaporating still offers several advantages that aren't available when dribbling. If I ever need to treat again, I will probably use the old evaporator. But the old evaporator had its place but has been retired for awhile now.

Regards
Dennis
Thinking my PMS oxalic fumed surviving bees trumps a thermocouple in a lab every time! And that's no joke! But it's certainly not idiot proof. And apparently the lawyers don't think a temperature controlled one is either :>)))

[ November 13, 2006, 10:52 AM: Message edited by: D. Murrell ]


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## Finman (Nov 5, 2004)

.
Here it is said that oxalic acid stays as oxalic after heating 
http://www.biovet.ch/shop/global/Imkerei/Varroa/VARROX%AE-Verdampfer::2.html?language=en

In chemistry I may find that if you heat oxalic acid with waterless clycerol it makes formic acid. http://en.wikipedia.org/wiki/Formic_acid


Here point 10: http://www.jtbaker.com/msds/englishhtml/o6044.htm
Carbon dioxide and carbon monoxide may form when heated to decomposition. May also form formic acid.

After searching from internet I am not any more sure that heating oxalic acid produces formic acid and that is that way how it works with varroa. I read that from a Russian bee research.


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## drobbins (Jun 1, 2005)

hmm,

well I can say from doing test runs in the open on the Heysler unit that some of the acid melts and then vaporizes, I just figured it melted and then evaporated into OA vapor.
actually, this link Finman posted 

http://www.biovet.ch/shop/global/Imkerei/Varroa/VARROX%AE-Verdampfer::2.html?language=en

says just that
Jim, where did you get your info that in decomposes into formic and CO when it melts?

Dave


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## drobbins (Jun 1, 2005)

actually, the MSDS says it melts at 101 C and boils/sublimes in the temperature range Jim mentioned
149-160C
which sounds to me like once it vaporizes it's removed from the heat source and the possibility of further heating to cause thermal decomposition is removed
what am I missing??

from the MSDS
</font><blockquote>code:</font><hr /><pre style="font-size:x-small; font-family: monospace;"> 
9. Physical and Chemical Properties

Appearance:
Transparent, colorless crystals.
Odor:
Odorless.
Solubility:
ca. 1g/7mL of water.
Specific Gravity:
1.65 @ 18.5C/4C
pH:
No information found.
% Volatiles by volume @ 21C (70F):
0
Boiling Point:
149 - 160C (300 - 320F) Sublimes.
Melting Point:
101.5C (216F)
Vapor Density (Air=1):
4.4
Vapor Pressure (mm Hg):
< 0.001 @ 20C (68F)
Evaporation Rate (BuAc=1):
No information found. </pre>[/QUOTE]Dave


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## drobbins (Jun 1, 2005)

>I made repeated
measurements made with real thermocouples,
so I offered objective fact, rare as it
may be on BeeSource.

please post your data Jim
inquiring minds want to know

Dave


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## brent.roberts (Dec 31, 2005)

I just got my Heysler a few weeks ago.
As it suggested I tried it in the open first and observed that it started vaporizing 30 to 40 seconds after the power was applied. Leaving it on continuously made is splutter and get a bit exciting. So when I do my hives I connect for 45 seconds, disconnect for 10 seconds. Reapply for 10 seconds etc until the total time is about 80 seconds. The Heysler comes out with a clean dry white powered that blows in the first breeze. When I left it on continuously it spluttered and finished with a bit of a black scorch around the little aluminum box.

Just apply the 6', 215 lb thermostat.

No claims on science or data here. But it works.
Killed nearly 40,000 mites in 3 weeks, and still counting.

[ November 13, 2006, 10:34 PM: Message edited by: brent.roberts ]


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## drobbins (Jun 1, 2005)

Brent

I think the difference is if you leave it plugged in, you boil the liquid, if you pulse it like you mention, you just evaporate the liquid
If you stand close enough to pulse it like that take care not to be exposed to the vapors
kills the heck out of the mites doesn't it









Dave


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## brent.roberts (Dec 31, 2005)

Been watching the air flow pretty carefully. So far so good. Don't even know what it smells like.

I guess when you know what it smells like its too late!


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## kensfarm (Jul 13, 2006)

"The problem is that none of the vaporizers have
any sort of thermostatic control at all."

If the vaporizers are 12 volt or 120.. I wonder if you could use a dimmer switch as a temp control.. you could test the temp.. and mark the spot on the dimmer switch.


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## Finman (Nov 5, 2004)

.
Here are two advices how to use vaporizer

http://www.dave-cushman.net/bee/oxalicthorne.html

http://www.honeybeeworld.com/diary/articles/cor.htm

.


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## drobbins (Jun 1, 2005)

hmm,

this seems to be the info Jim was speaking of

http://www.honeybeeworld.com/diary/articles/oxalic_sublimation.htm 


Dave

[ November 14, 2006, 04:16 PM: Message edited by: drobbins ]


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## betrbekepn (Aug 7, 2006)

Check out this oxalic acid evaporation machine. http://www.alfranseder.de/deutsch/raehmchenkamm.php I can't make a direct link so first you'll have to click on the english flag, then go to the oxalic acid evaporation machine.

[ November 15, 2006, 06:51 PM: Message edited by: betrbekepn ]


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## Finman (Nov 5, 2004)

.
Finnish beekeeping specialist Ari Seppälä calculated from Finnish varroa trickling research data following lag time :

After
cure ---- rate of all falled 
1 week ---- 54 % 
2 week ---- 20 %
3 week -----13 %
4 week ------8 %
5 week ------5 % 
.


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## Dave W (Aug 3, 2002)

Oxalic Acid - Vaporization Method

Monitoring Results - Evaporation method is slower (to kill mites) than other OA methods.
One day after treatment, only 10% of total mites killed are found on hive bottom. After 1 week, 80% are killed. To determine exact number of dead V-mites, count mites for a period of 3 wks. www.apis.admin.ch/en/krankheiten/docs/saeuren/osbienenvertraeglichkeit2003_e.pdf - Accessed 1/19/05.

Mite drop increases 270% from day 1 to day 8, but increasing only 18% over next 36 days. Oxalic acid kills mites for at least 44 days (6.3 wks) - see http://www.mellifera.de/engl2.htm (Accessed 2/3/05), Figure 2.


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## Finman (Nov 5, 2004)

.
A finnish researcher Seppo Korpela has calculated during many years mites' drop 

year 2000 altogether 34468 falled mites 

1-2 weeks 96% 
3-4. weeks 2,4 % 

v. 2004 ... 10730 mites: 

1-2 weeks 98 % 
3-4 weeks 2 % 

Y 2005.... 12270 mites 

1-2 weeks 96 % 
3-4 weeks 4 %


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## jamiev (Sep 14, 2005)

trickling sure is a lot easier and results seem to be just as good !I just treated a hive on Friday using OA trickling method.. Did not count yet but there were many dead mites on the bb after 24 hours. I'll keep monitoring but it looks like it is working well so far.


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## Ross (Apr 30, 2003)

You know, the only thing that really matters is whether or not it knocks down mites. The crack pipe clearly works for a minimum of investiment.


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## Finman (Nov 5, 2004)

<<for a minimum of investiment.>>

If you bye with 10$ oxalic acid, you may handle 70 hives. It is not investment, just running expenses.

.


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## brent.roberts (Dec 31, 2005)

Just to throw another curve into the kill rates idea, all of the counting I did which was 40,000+ mites, and I would think the counts of all other studies did NOT count dead mites. They counted only FALLEN mites.

How many dead mites are still lodged under the layers of the bees abdomens ??? I don't think anyone knows. I do think they get loosened and fall over time. 

Maybe the different treatments have similar kill rates but the fall count is different because the treatments cause different grooming / hygenic response so we think we get a better kill rate with one.

Someone would need to find a way to count mites on bees and see how many were still alive, after any given treatment, and therefore not falling. From what I have read counting live mites on bees is next to impossible.

I wonder if they "talk" or something and we could detect them in some way other than visually ???

[ December 25, 2006, 07:53 PM: Message edited by: brent.roberts ]


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## kensfarm (Jul 13, 2006)

Brent.. how about a test using some powdered sugar to help facilitate the bee's to groom themselves of the dead mites?


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## Ian (Jan 16, 2003)

David B,
you speak of a commercial OA vapourizor. Who manufactured it? I know of one being developed by Medivet in Alberta, really interesting device allowing treatment to switch from single to double hive application, 15 second/hive treatment. BUT is has yet to get through all the hoops yet! Costly machine, perhaps there is too much liability involved in providing a device like this?

Test stripps on hives I had dribbled OA showed good mite drop within the day of application. Actually, it compaired to checkmite quite closely, in my limited findings anyway.
But its what alot of guys were telling me up here as well.
It did do a number onthe smaller hives brood. I had previously beleived OA was easy on the brood. I guess that pre assumtion was wronge. They suggest to have good conditions when treating the colonies.


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## D Coates (Jan 6, 2006)

I've got a Heilyser OA vaporizer being shipped down to me as I type. Does anyone have a video of one in action? Reading everyones findings is great and VERY appreciated but a video is worth more than 1K in words.


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## Ian (Jan 16, 2003)

Where is it made, how much did you spend?
What material is it made of?
How does it measure the dosage?

Tell me a little about this device,... I'm interested,

[ January 04, 2007, 11:43 AM: Message edited by: Ian ]


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## D Coates (Jan 6, 2006)

Ian,

You're in luck, this is made west of you but on your side of the border in Sidney, BC. He charged $80 US funds, that included shipping. The website needs some work but with a little poking around you can find a picture of the JB200. You can't order it via the website but I have found Mr. Heinz Kaemmerer to be responsive to an E-mailed question as well as answering his phone.

http://www.members.shaw.ca/orioleln/

The other one I found that is also shown in this thread is below. It is a very clean looking design but I couldn't find anyone who sells it in North America and I was not comfortable buying over the pond. http://www.biovet.ch/shop/global/Apiculture-Area/Varroa/VARROX%C3%86-Vaporiser::2.html?language=en


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## Ian (Jan 16, 2003)

Thanks D Coates. Not exactly what I thought you ment. I thought you were reffering to a commercial applicator. Hope it works well for you, the numbers are impressive!

Whats the buzz on Oxamite? Does anyone have any experience with this product? Sound like a good idea, and in theory it should be as effective as dribbling it on. I wonder if the bees 5 week exposure to the OA causes them harm? I would think so.
Whats the cost per strip?


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