winter oxalic treatment

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Queen Bee
Nov 8, 2008
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This is recipe for oxalic from cusman site.

Treatment with Oxalic Acid
Oxalic acid is a short-lived treatment that only kills mites that are living on the bees (ie. those in a phoretic state). It does not kill mites that are in the brood. When there is brood present in a hive, only about 15% of the mite population are normally on the bees (ie. the rest, 85% are in the brood). It follows, therefore, that oxalic acid works best on colonies that are broodless at the time of treatment This is the ONLY CONDITION (broodless) in which oxalic acid should be used. It can of course be used on swarms (both natural or artificial) if they suspected of carrying a heavy load of mites (normally they carry very few mites).

Treatment should be delayed until colonies are in a broodless state. In our area, this does not usually occur until mid-December or even January. After the 'Apiguard' treatment (in August-September), it is recommended that the catch tray should be removed, the insulation taken out of the cover board and some top ventilation re-instated. This will make me hive much cooler (I know this will horrify some people) and ensure the cessation of brood-rearing as the weather gets colder. Discretion should be exercised with weak colonies.

The treatment material is 3.2% oxalic acid in a 1:1 sugar solution. The recipe for making this is as follows:-

Make up a sugar syrup consisting of 1 kg sugar in 1 L of water. To this should be added 75 gm of oxalic acid dihydrate and well mixed. This will make 1.67 L of treatment material. Accurate weighing of the oxalic acid is essential because under-strength will give a poor mite kill and over-strength may kill bees!

This sweet solution is poisonous and should be stored securely out of the reach of children!

Procedure for treatment with Oxalic Acid by the Dribble Method

Fill the 50 ml syringe with treatment solution (oxalic acid).
Remove the roof.
Remove the top box (shallow or deep) with cover board in place and rest it on the upturned roof.
Treat the lower box with about 5 ml solution/occupied seam of bees.
Replace upper box.
Remove cover board and treat any seams of bees as for the lower box (the upper box will often have no bees, especially if the weather is cold).
Replace the cover board and roof.
This procedure usually takes less than a minute/hive. It is safe to carry out the treatment in cold conditions with the temperature down to 0?C. If the weather is cold and the bees are well clustered, they will usually not even have got moving until the deed is accomplished. However, it definitely does pay to ensure you have the correct bee space between boxes so that they come apart readily without disturbing the bees - it is surprising how many hives to not meet this specification.

With a kill efficiency of about 90%, the oxalic acid treatment will not only mop-up mites that escaped the 'Apiguard' treatment 3-4 months previously, but it will also kill any mites that have been bred in that time or have been recruited from external sources.

After the oxalic treatment has been completed, the top insulation should be re-instated and any top ventilation closed-off. Mites will continue to fall for about a fortnight after which the catch tray can be removed.

Walter Shaw

Beekeeper Protection
It cannot be stressed too strongly that oxalic acid is an aggressive substance and needs to be treated with respect. Acid resistant gloves and goggles should be worn and an apron of the type used by mortuary attendants, along with wellington boots that have the tops covered by gaiters so that any falling liquid cannot fall into the boot. A respirator that has specialised organic acid filtering will be required in cases where the acid is sprayed or vapourised. Oxalic acid is also poisonous to humans by ingestion.

This treatment is best just before or after xmas,and is organic so can bee used by natural beekeepers ,top bar hives ect.
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Thanks for that Hivemaker great post!
I purchased some Oxalic Acid from Thornes a couple of months back in powder form,I did notice they also do a ready made bottle with aplicator.

Also a member on Ebay is selling small packs.
To smaller dosage 3-5 hive langstroth

100 g sugar
100 g water
7,5 g oxalic acid.

When you handle 2 store hive, you need not take upper box away.
If stores have burr, it is difficult to get them apart and more difficult to put back.

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Thank you finman,all imformation is well appreciated. The stuff on e bay is sold by doug jones he is bee inspector up north, he also supplies carnica queens from there proper homeland.
More information about OA

Here is some valuable links to common questions
Researches have been done 10 years and OA is one of the best methods when hive has no brood. Brood may have 80% of mites and it does not affect inside brood caps.

European varroa group. You may seach reports by their name.
Coordination in Europe of research on integrated control of varroa mites in honey bee colonies

Clear advices from Canada

Oxalic acid vapour treatment

Harms to brood area if you trickle during summer. Results are worse than what mite can do

How soon mites die when you give oxalic cure - After two week you see the result

Brent.roberts have made repeated oxalic acid vapour cure and results in table:

Oxalic acid levels in human body

Oxalic cure and human health - oxalic acid residuals classification means that the substance is evaluated as not dangerous, and no residue limit is needed to protect the consumer.

OA in human food stuffs
Oxalic is a very good treatment for varroa,and with thymol and formic,we have no need to worry much about varroa,drone comb is a good way to monitor mites when you have solid floors just by examining the larvae for mites.
I am doing Thymol in the summer and OA in winter,should I need to do Formic acid as well?
No you would only use formic if you do not use Thymol. It is also dependant on warm weather,other countries have used this for well over 20 years.
I think this should be a "sticky" :)

Also there will come a point in the great British winter when we get a cold snap and it's about 10 days after that when the treatment should be done (I think) for maximum effect - please correct me if I'm wrong. Anyway we should be keeping an eye on the weather so the correct time can be advertised here.
Stickey it is :)

Thanks to everyone who has contributed to the thread so far.
Treating over the Christmas period seems to work quite well for me...
Hi Oxfordbee welcome to the forum:cheers2:

I was thinking between xmas and new year if the weather is ok.
ChrisB wrote that temperature affect on efficay of trickling. He told that he saw it with his own eyes. In 12C temp only 75% get OA compared to +2C.

Well Nanetti from Italy have made reseach in different temperatures.
In +8C the efficacy was 99% and in -1,5 C it was 98%.

It is said nowhere that tempereture affects in trickling.

Chrish you better find yourself what you need for evidence.
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Hi all

I have been Oxalic trickling for about 5 years and have never worried about temp, nor have I noticed any difference in results. All that I worry about is that the bees keep surviving and mites keep dropping :svengo:

Regards Ian
I checked my bees last week and had all hives with a few bees flying,went to have a look this afternoon and not a single bee seen,it is very cold so I am not suprised.

I think tomorrow I will do my OA treatment as the forcast is more of the same.
I made my own Oxalic Acid vapouriser similar to the one being sold by Bickerstaffs. Three weeks ago I treated all of my hives with it, along the lines of the video they had on Youtube which I can't seem to find anymore, and it appeared to work very well. It didn't seem to upset the bees at all. I didn't monitor the mite fall (wish I had now) but didn't expect too many as I followed Hivemakers Thymol regime religously. Does/has anyone else used the Oxalic Acid Vapourisation method?
Jonathon, you do realise if you are following this regime You will have to do a further 2 treatments a week apart as I do.
Mites will continue to fall for about a fortnight after which the catch tray can be removed.

What specific purpose does the tray serve other than give you a warm feel as you count the mite drop? For the odd day or so post treatment it possibly makes sense, beyond that I can't see any reason why the bottom of the hive shouldn't be 'open' so that debris falls out of the hive.

Leaving the tray in permanently when applying vaporising treatments makes sense, for everything else :confused::confused:
Yes it gives you a warm feeling,also good when trying different treatments,the tray is handy to see the effect,i don't count mites,but can see if the treatment works,or not. but being as 99% of my floors are solid,its difficult to leave them open,and i like solid floors and have no intention of changing.just use a % of the mesh ones to monitor what will be happening in the rest of the hives.
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