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Author Topic: Oxalic Acid Vapor - No Result- WORRIED.  (Read 2547 times)

Offline melnik

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Oxalic Acid Vapor - No Result- WORRIED.
« on: September 07, 2013, 09:27:43 PM »
Hello all,

Right of the bat, I am a newbie in this activity as well as the forum, so dont hate.

So I vaporized my hives with oxalic acid several days ago, the recipe was done to proportions as recommended here as well as on other forums. I did the procedures as directed, so an error on my part is very low.

Now, I opened up my hives, today (4 days later) there were maybe 2 or 3 mites at the bottom, and even those probably died because it was time for them to leave this world.
I dont understand what is the problem, I hear people have amazing results with this treatment method almost instantly, but apparently it didnt do anything on my hives. I know for a fact that my bees have a big problem with the varroa mites.

Please help. The fall is here and its time to do something about this issue. Im worried to loose my colonies due to these mites again.
Any suggestions will be greatly appreciated.

Online kathyp

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Re: Oxalic Acid Vapor - No Result- WORRIED.
« Reply #1 on: September 07, 2013, 09:55:25 PM »
what was your mite count when you started?  how much brood do you still have in the hives?
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Offline buzzbee

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Re: Oxalic Acid Vapor - No Result- WORRIED.
« Reply #2 on: September 08, 2013, 04:19:09 PM »
Is this a first year colony from a package of bees?
If so, by what criteria did you determine you have a mite problem?  Most first year packages have a few mites but usually do not become a heavy burden until year two or three.
 This statement also explains why many new keepers lose hives in the second or third winter because they think they have survivor bees coming out of the first winter.
 Year one a colony spends more time raising worker bees than drones,leaving less drone brood for the mites to exploit. And on top of that,the bees have a period of zero brood until comb is built and first eggs are hatched,keeping mite populations to a minimum first year.
This may well account for the low kill rate.

Offline melnik

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Re: Oxalic Acid Vapor - No Result- WORRIED.
« Reply #3 on: September 10, 2013, 11:06:57 PM »
Hello, thank you for your responses.

This is a summer nuke that I put together myself. I didn't take an actual count of mites, but I do know, and have seen that there are a lot of them on the bees. 
The brood is 5 deep and 5 medium. So I do agree that this is a new colony, but as I mentioned it does have a mite problem.

Any ideas why the vapor wouldnt work, any suggestions?

Thank you!

Online Michael Bush

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Re: Oxalic Acid Vapor - No Result- WORRIED.
« Reply #4 on: September 11, 2013, 02:40:31 PM »
Back when I tried it, I found Oxalic acid vapor to work very well at killing Varroa.  It was reasonably forgiving as far as dosage, closing the entrance etc.

The only real way to measure the efficacy of any treatment is to monitor it before (natural drop in 24 hours) during (treated drop in 24 hours) and after about a week, measure it after (natural drop in 24 hours).  You can't really quantify that it worked or didn't by how many you think you see.  You may have a good eye for it and other people may not.  Also keep in mind that in two weeks all the mites in the brood will be out and there will be no noticeable difference...

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Offline danno

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Re: Oxalic Acid Vapor - No Result- WORRIED.
« Reply #5 on: September 12, 2013, 08:52:09 AM »
As MB said Also keep in mind that in two weeks all the mites in the brood will be out and there will be no noticeable difference...
The first round most of the mites are under cappings.   This is the reason that you need 3 rounds a week apart.   

Offline JWChesnut

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Re: Oxalic Acid Vapor - No Result- WORRIED.
« Reply #6 on: September 21, 2013, 09:47:36 PM »
OAV doesn't  kill mites by fumigation.  The vapor settles and forms a layer of micro-crystals on surfaces.  This means the vapor has an extended kill period, but one without much initial drop like those used to formic or thymol are used to seeing.  

It also means that the impact is cumulative-  the vapor crystal layer can become toxic to bees  as it builds up through repeated application.

I don't believe the initial protocol was for unlimited applications, and I worry that the repeated sub-toxic use may actually accumulate to bee-toxic levels.  

I say this because several years ago, I  killed colonies outright by a double dose of OAV.  Mis-read the weight/volume calculation of the nominal 1/2" pipe cap.  I applied 2 cap fulls  or 2x2gram= 4 gram  instead of 1 cap = 2 gram.   This killed hives in 24 hours with a heavy white crystal layer left behind.

I am using OAV again this year, but cautiously.  I don't see the 1x week for 3 week protocol documented, seems an adaptation of the sugar and hop protocol.  I think it may result in a 6 gram (2gram x 3) hive loading which might be very near the bee toxic limit (per papers on OAV in a single application).  

The European papers on the OA dribble note that sugar solution is likely not so bees will ingest the OA, but to raise the viscosity of the solution so it dries and forms the micro-crystal bloom in place on bee bodies and comb.

One problem with OAV is once it is applied, there is no turning back- the vapor crystals settle everywhere forming a characteristic white haze.  If you over-apply formic or thymol, you can pull the pads and let the hive aerate.  I don't think you can wash the crystals off an overapplication of OAV effectively.

Offline edward

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Re: Oxalic Acid Vapor - No Result- WORRIED.
« Reply #7 on: September 22, 2013, 12:58:09 PM »
Take 1- 2 dl of bees from the brood nest and put them in a jar with a mesh lid on that is Small enough to keep the bees in and big enough so that the mites can fall out.

Take a few spoons of dry icing powder and put into the jar of bees and shake well so all the bees are covered in the icing sugar and are White.

After a few minutes shake the jar vigorously.

The sugar covered bees start to clean themselves, also it cogs the mites feet so they cant walk and grip on to the bees.

Shake the icing sugar into a fine mesh sieve, then wash the sugar away with water and you will bee left with the Varroa mite that were on the bees.

This method i also used to determen apistan resistance in mites : put some bees in a jar with a piece of apistan for 24hrs, shake out the dead mites Count them, then do the sugar treatment and Count the dead mite to determen if they are resistant to the apistan or other mite treatments.

mvh Edward  :-P