# Oxalic Application



## Matt Beekman (Dec 15, 2007)

I was wondering if any commercial beekeepers have tried an oxalic application when feeding pollen supplement. During the winter I feed my patties in the middle; so I already have the split and if applied in mid to late December the hive should be as shut down as much as possible.


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## LSPender (Nov 16, 2004)

And why would want to use oxalic acid? also, if you do is not it a bit cool in the valley this time of year?


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## David LaFerney (Jan 14, 2009)

Because it is a substance which naturally occurs in honey, spinach, and several other foods - and it's safe effective, and cheap? Also the levels of OA in the hive return to normal levels quite quickly - or so I have heard. However even though it is approved - and widely used - in almost every other country it doesn't seem to be here in the USA. Odd.

However in places where it IS used, late fall after hives become mostly broodless seems to be typical - even where winters are cold.


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## jim lyon (Feb 19, 2006)

I don't really see a problem with that Matt, if the hives are broodless and the temps arent too cold I would say the sooner the better (assuming you feel that your mite numbers justify it. There have been some studies showing that oxalic can result in a decrease of brood shortly after application. Splitting a double is an excellent way to get the treatment to the cluster. Smaller hives dont seem to tolerate it very well though. We have had good results with a 3.2% solution.


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## crofter (May 5, 2011)

Perhaps different states have different policies on the usage of a substance in a beehive. Because something be not officially approved, does that make it an offense to use or merely an offense to promote or claim it as an approved miticide.


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## David LaFerney (Jan 14, 2009)

I talked briefly with a state inspector - I'll not say which state - and he was evasive in a manner which led me to believe that it may or may not be a gray area which he would be inclined to overlook/not ask about. IE "I'll get back to you..." or rather never mention this again.


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## oblib (Oct 28, 2011)

It is wood bleach, you are not going off label to treat for mites,.. you are just tryng to get the inside of your hive clean and shiney for your bees


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## crofter (May 5, 2011)

oblib, we are going to bleach the wooden wares in a couple of hives. Will wait a week or two and check there is no brood. Have the finishing touches to put on a DIY glow plug oxalic acid vaporiser, though I understand it is approved in Canada as I purchased OA chrystals from a bee keeping supplier.


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## irwin harlton (Jan 7, 2005)

" you are just tryng to get the inside of your hive clean and shiney for your bees"....it just happens to also kill mites, and effectively. I'm using a home made vaporizer, pictures of vaporizer http://s43.photobucket.com/albums/e365/buzz1356/bees/oxalic crystal vaporizer/
patent pending


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## Matt Beekman (Dec 15, 2007)

jim lyon said:


> I don't really see a problem with that Matt, if the hives are broodless and the temps arent too cold I would say the sooner the better (assuming you feel that your mite numbers justify it. There have been some studies showing that oxalic can result in a decrease of brood shortly after application. Splitting a double is an excellent way to get the treatment to the cluster. Smaller hives dont seem to tolerate it very well though. We have had good results with a 3.2% solution.


The above quote regarding a decrease of brood is what I am trying to get a complete understanding of. I am wondering if a patty would counteract any decrease in brood rearing. Most of my almond contracts have a frame commitment; I wouldn't want to knock back a 10 frame colony to a six right before almonds. Buy the idea of hitting the mites when they are exposed with an effective soft treatment is appealing.


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## Matt Beekman (Dec 15, 2007)

LSPender said:


> And why would want to use oxalic acid? also, if you do is not it a bit cool in the valley this time of year?


To answer your questions regarding temps., it would not be too cold in the valley in mid to late dec. Given the time, cost and efficacy I wonder why it is not a more common practice?


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## jim lyon (Feb 19, 2006)

That is why I am suggesting the sooner the better but I really doubt that its a concern. I'm not aware that there has ever been any evidence that an oxalic application can cause a future reduction in brood only that one study somewhere claimed a reduction in brood shortly after application compared to a control. FWIW I have used oxalic when a lot of brood was present and never noticed any slowdown in those hives from casual observations.


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## honeyshack (Jan 6, 2008)

Mr. Harlton,
Checked out the pic...interesting way to wrap bees. How does the pipe work?


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## crofter (May 5, 2011)

Is there not a considerable difference in Oxalic syrup dribble or liquid spray and the application by heat vaporization of the dry chrystals. In the latter, you do not have to open the hive and does not wet the bees. Have read somewhere that the dribble method should only be done once but fuming can be done any number of times.


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## BEES4U (Oct 10, 2007)

The reason that you have to repeat the vaporizing is because the oxalic acid kills the phoretic mites and not the ones within the capped cell.
Therefore, the vaporizing is done 3x


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## dgl1948 (Oct 5, 2005)

Irwin, that is a pretty fancy machine. We have used the drip method for a few years but this year we purchased the varrox vaporizer to try. The things I like about this method is it can be done after the hives are wrapped without opening them and with our conditions here that is important. It does an very good job of filling the two brood chmabers with vapour. If you follow the direction for timing with this unit it works like a charm. (burn time and wait time) It also has to be about the lowest cost treatment going and mites should not develop a resistance to it. The only thing negative is it is slow to use. It took us about 6 minutes a hive so you need more than one unit if you are doing a lot of hives.


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## irwin harlton (Jan 7, 2005)

I would hardly call my vaporizer fancy, something I thought a bit about and tinkered with till I was half happy, it cost me a lot less than $100 ( used parts ).I supplement the heat source from the glow plug with a little propane heat , by using a little more oxalic in the burn chamber I can do two hives in the time it would take to do one.You are right there are a lot of pluses in the use of oxalic sublimation to treat mites this time of year under our conditions, hives being wrapped , COST of treatment, etc.And the only big fault is the time it takes per colony.
I have been following Allan Dick's fall treatment at http://www.honeybeeworld.com/diary/default.htm. He used a Cowan vaporizer with four units,so four hives could be done at one time,I hope to build something similar.Cowan currently wants $6600 for their machine.This maybe relatively cheap when you consider the cost of strips and having to use them for a number of years
I hope to shoot a video of my vaporizer in operation and show how it works


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## Vance G (Jan 6, 2011)

Mr harlton, how do you load the dadburned thing? Is the blower a mandatory part of it?


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## irwin harlton (Jan 7, 2005)

I load 5-6 grams of oxalic into the the first pipe fitting coming off the bottom of the galvanized tee. It is a brass 3/.4" reducer fitting where the head of the glow plug resides , that supplies the heat.The next 3 pipe reducers allow me to thread the glow plug into the last reducer. The 12 volt blower certainly helps to move the oxalic vapor through the hive, I block the bottom entrance with a piece of wet towel , the vapor can bee seen exiting the top entrance,which I leave open.
honeybeeworld has a video of Cowans vaporizer killing mites at https://skydrive.live.com/?cid=7a1f...DBBEA6AC0D2&id=7A1F9DBBEA6AC0D2!354&sc=photos


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## G B (Nov 6, 2009)

Hello Irwin I would be curious to see this machine in action please post on here when you get a video of it in action. Thanks George B


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## dgl1948 (Oct 5, 2005)

The varrox worked very well but as I mentioned the big issue was the time per hive. It was taking us about 6 minutes per hive. I think that if a person was to use 4 of these so you could do eached wrapped unit at once it would work out very good. We did a burn outside of the hive to see how much vapour we would get and it is considerable. There was no problems in filling a hive with vapor. I am sure that every bit of the hive would be filled. Cowans unit at $6600.00 is a bit pricy when compared to 4 varrox units. The varrox would be faster to move and set up as well when dealing with wrapped hives.. One of our concerns was the issue of escaping fumes and coming in contact with it. We used the recomended protection and were suprised that it did not seem to be an issue. We sealed the top entrance on the wrap with tape and used the wet towel to seal the entrance as well. We would pull the varrox from the hive , set up for the next one and leave the ones treated closed up untill all 4 were done. Then we would open them as the next unit was being treated and the vapor was not a problem.
The other thing I like about this is if one wants to treat again in March, again there is no opening of the hive.


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## camero7 (Sep 21, 2009)

I used the varrox yesterday on one yard. Based on Allen Dick's reports on his web site, I've quit closing up the hive. I just make sure the vapor comes out the small top entrances I use in the winter. One hive - I've been slow to put my mouse guards in - had a mouse come flying out the entrance. It was moving fast so I don't think the vapor is that deadly. I don't wear protection, get a whiff of the vapor from time to time and it is irritating but not overwhelming. Allen mentioned several drawbacks to the Cowan unit on his site. For those interested in OA vaporization it's a must read. http://www.honeybeeworld.com/diary/


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## Vance G (Jan 6, 2011)

Mr. Dick's diary did a bit of a compilation of the oxalic treatment today and I concur it is a very good study on the subject.


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## virginiawolf (Feb 18, 2011)

Wow!!


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