# General beekeeping > Bee health >  Help Oxalic Acid.

## Daveoneflowers

Hi to you all. I am new to forums and its my first full year of beekeeping so please be gentle. I would like to vaporise oxalic acid to treat for mites. I think it is more of a commercial approach but makes sense in cold wet windy weather. I have seen various home made gadgets that work in a fashion but there are always better ideas out there. Does anyone have a reasonably priced method. I thank you for any help, and may I also say congratulations on your forum.

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## prakel

I'm going to leave answering your vaporization question to others who know what they're talking about, and they will answer that's for sure.

In the meantime, Hello, it's nice to see a new poster here; but one thing for sure,  "...so please be gentle" is definitely an unnecessary plea on this friendly forum.

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## Daveoneflowers

Hi there, I was on one forum and they where always the same people and the shot you down in flames. This one has the best review and is informative and interesting. It's less active but not used for sarcastic banter. Thank you for taking time, that was nice.

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## Rosie

Hello Daveoneflowers.  I can't help you with your vaporising kit because I never use it but I have been trickling for about 7 years and have never had a problem with it.  You will probably get someone to advise you on vaporising equipment but these days the vast majority seem to prefer the trickling method as it's cheap, effective and relatively safe for both you and the bees.  As for the weather I think cold is good although I would avoid wet and windy.  I wanted to trickle mine this week but it's too warm for my liking.

Good luck whichever method you go for.

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## Daveoneflowers

Thank you for taking the time to reply, the only reason I want to use a vaporiser is to avoid opening the hive and others seem to have good results. I should probably just get on with it and not think too deep.

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## beejazz

Hi,  I'll be trickling again this year, don't like to do it, but the alternative of not using oxalic could be worse, I've done it 3 times now, always get a good drop of dead mites, and can't see that it disturbs the bees that much.  It doesn't take long, a minute or two, and i don't do it in very cold weather, I choose a mildish, dry, still day.  The thing with vaporising is the equipment can be expensive, and for me at this point not worth it;  my hives, also, are not near enough to car/house; but the cruncher is, if not done correctly its not just the bees that may die!

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## Daveoneflowers

Thank you, I know you have to be careful. Any advise is appreciated.

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## Blackcavebees

Hey Dave, welcome to the forum

I used Oxalic by trickle for the first time last winter. Easy to do and if you have only a few hives a much cheaper solution. There are "home made" vaporizers made using a 12v batt and a glow plug from a diesel engine which work but the stuff (oxalic) is nasty stuff and could do you a lot of harm without proper safety equipment. So for me I'll be dribbling again this winter. Your local doctors or chemist should give you a syringe if you ask politely (they often ask what for and it's a lead in for me to sell some local honey!)

Not sure if everyone does this, but I dribbled with warm syrup so not to totally chill the cluster. Obviously not too warm but I used one of those cup warmer cover things to keep it warm before pulling some out with syringe. Also, the commercial vaporizers are slim enough at end to fit through entrance block whereas some homebrew efforts I've seen need entrance block removed - just a thought if you are thinking of making one.

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## fatshark

Hi Daveoneflowers … if you open the colony on a cold, calm (and dry!) day the colony will be disturbed very little. I use one of those £1 dispensing bottles that Thornes sell - a reservoir with an inbuilt 5ml measuring chamber. I prepare and pre-warm the oxalic acid in a Thermos flask (clearly labelled and NOT used for anything else) and use this to refill the Thornes bottle as I go round the colonies. It's very quick. In fairness I've not used a vaporiser, but am perfectly happy treating using OA in this way.

I'm near you (Midlands) and - like Rosie - think it's too warm at the moment. I'll wait until we have a protracted cold period so I can be as sure as possible that the colony is brood less.

There's a recent suggestion that colonies should be treated earlier than this (i.e. mid-winter, after a prolonged cold snap) and that the colony should be checked for sealed brood (and any found should be destroyed). Until I see some evidence that this does more good than harm I'll be sticking with the 'conventional' trickling approach.

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## prakel

> the only reason I want to use a vaporiser is to avoid opening the hive and others seem to have good results. I should probably just get on with it and not think too deep.


Nothing wrong with thinking!

On the subject of opening hives in cold weather, my own experience (even though a lot of you might not think that the Jurassic Coast qualifies as cold), has been that it really doesn't appear to do any harm: I've a couple of posts on this forum about intervention last Jan/Feb that not only probably saved one nuc but also revealed -to me- some interesting queen rearing behaviour which I might not have accepted without seeing it for myself. There's always talk that it may cause the balling of the queen but I don't know how much that's speculation rather than actual experience; put another way, how many people who say that it's awful practice that'll lead to disaster have actually taken combs out during the deep winter months? I believe that the late Bernhard Mobus did a lot of research on winter brood rearing -which must have required opening hives through the cold Aberdeen winter, maybe 'Poly-hive Pete' will present some more detailed information on that, in the meantime, Karin Alton from LASI in Sussex has recently advocated removing and destroying sealed brood at the time of trickling:




> “it’s a fallacy that you can’t very quickly check for brood, we have opened hundreds of hives (very quickly- talking here couple of seconds) without any probs, even in cold, snowy January.”
> 
> “if you want to use oxalic acid, you MUST destroy brood before, as varroa hide in sealed brood, so waste of time and money putting OA on”
> 
> “Between 10th dec to 24th [in the UK] is the time with least likely/fewest sealed brood. uncap brood 48 hours before application, you would not need to pull out every frame, in fact you can tell by shifting the frames slightly if there is any, should be very few. if you use dribble method, you dont pull frames out anyway.”


Food for thought there.


*edits:* 

Cross posted with fatshark.

Karin Alton does go on to say (on the London Beekeepers facebook page) that sublimation is more efficient than trickling.

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## Blackcavebees

Gavin, I think we have two posts going on here on same subject

Thanks.  Did spot it last night but lost the internet for a while (found it again!).  Welcome, Dave.  G.

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## Jon

I bring along a flask of hot water to the apiary which I pour into a container. I stand the bottle of Oxalic in this before trickling so that I am not tipping a cold liquid over the bees.
The best temperature for trickling is a coldish day, 2-4 C when the bees will be tightly clustered.
If you apply Oxalic in mild conditions the bees won't be tightly clustered and they will occupy more seams which means that they will get a much higher dose of oxalic if you base the dosage on counting seams.

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## gavin

I'll be treating bees today, and showing anyone who turns up at the association apiary at 1pm.  Trickle/dribble of course, so I have no experience to offer Dave.  None of that namby-pamby warmed-up flasks stuff here - these are *Scottish* bees so they'll get it as it comes!  The bees themselves will be cool (should be no brood), and the small volume per seam of bees will only temporarily change the temperature of the few bees hit by the dribble. They may already be at a temperature close to the inside of my car.

Might there be more brood than normal at this time of year?  Really don't know. Not sure that some flying and a little pollen coming in means they're raising brood.  Can anyone guarantee that in a month's time they'll be less likely to have brood?  

Digging out brood before dribbling?  That has to be very disruptive and there's no way I'd do that at this time of year.  And as for sublimation being more efficient than trickling, I doubt that.  I seem to recall published work that implies that it is slightly less efficient (in terms of % mites destroyed per treatment).

Trickling:

- fast and easy
- very little equipment needed (and it is light)
- you only treat the bees, not their furniture
- safe for the operator, wear gloves and take care not to splash in the eyes
- can just pour away spare solution on the ground
- can be scaled up to do large numbers using a sheep medication dispenser
- ideal time to check stores by looking down on frames (Bees at top? cells at top still with sealed stores?  Heft it with roof off?)
- ideal time to put fondant on light colonies, straight on frames or better on QX (don't need it before now, about to start brood raising, you hope)

Sublimation:

- don't need to take roof off
- can repeat (apparently) but how do you know it needs it?
- needs equipment carried to your bees (car battery or source of heat as well as the vaporizer)
- requires fine particle face mask for anyone anywhere near (it is said there are records of beekeepers damaging themselves by inhaling oxalic)
- much of the oxalic acid lands on woodware and will remain there until the colony fills the box
- isn't well integrated with sorting winter stores issues
- folk say it is efficient for large numbers of colonies (but so is trickling)

Some LAs seem to go in for sublimation in a big way.  Seems a big mistake to me to show novices a more dangerous way of treating your bees.

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## prakel

> And as for sublimation being more efficient that trickling, I doubt that.  I seem to recall published work that implies that it is slightly less efficient (in terms of % mites destroyed per treatment).


I spent a while this morning trying to find a link to some research that came from LASI earlier this year (which I'm sure does exist). I think that it even made it's way onto the BBC website and into assorted papers too at one point which rated sublimation very highly and no doubt it was those findings which were driving Karin Alton's thinking. The problem, is that for some reason I can't seem to find any mention, anywhere. No references are coming up after several different searches.

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## Jimbo

I have experience of using both methods and in my opinion would forget the sublimation method. It is too much of a faff and on a health & safety point is far more dangerous to the operator due to the sublimation gas. The trickle method is cheaper and quick to do if you have to get around a number of hives. I usually trickle when the temperature is about 5 degrees and I don't warm the oxalic although it is not freezing cold either.

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## prakel

> I spent a while this morning trying to find a link to some research that came from LASI earlier this year (which I'm sure does exist).


......

http://www.telegraph.co.uk/earth/wil...wrong-way.html




> Now researchers have found that when applied as a vapour rather than a solution, and at a particular dosage, the treatment can remove virtually all traces of varroa from hives without any harmful outcomes for bees.......
> 
> Results from the trials have not been officially published, but Prof Francis Ratnieks told the Telegraph that in the most effective format – a vapour at a particular concentration – the treatment was 97 to 98 per cent effective.


Took a while to find, I seem to remember there was a fair bit of discussion on the net at the time but strangely that it almost all concentrated on the couple of almost throw away lines at the end referring to crossing with African bees.

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## The Drone Ranger

> Thank you, I know you have to be careful. Any advise is appreciated.


Hi Dave
I use the Varrox vapouriser it's a bit dear but solid 
The biggest supplier has gone nuts with its pricing and you get it much cheaper elsewhere

To make life easy this is the way I do it
The hive floor is an epoxy coated wire mesh above a solid floor with a varroa tray insert (similar to the link below showing Ian Craig's )
http://www.scottishbeekeepers.org.uk...a%20floors.pdf
You need to look at the last page to make sense of the next bit  :Smile: 

The varrox vapouriser is inserted between the mesh and the solid floors once the tray is removed
floor.JPG
2g of oxalic in vapouriser from the back of the hive then close the slot with foam (cheap from Dunelm Mills)
Go round front plug the entrance slot with foam as well
I use one of these batteries because it has a charge indicator,a handle and it's not heavy
http://www.amazon.co.uk/gp/product/B...?ie=UTF8&psc=1
Anyway connect the leads and move upwind for 2.5 mins then disconnect the battery

Masks like SCOTT PRO2 with A1B1E1 filters are designed for organic acids
You might use something cheaper but at about £20  it is worth it if you are considering bent tubes and blowlamp madness

The coated mesh floor isn't affected by acid it disperses the vapour well and doesn't remove heat from it
You can slip the varrox past the foam and move on to the next hive after 10mins leaving the foam for another 10 mins

Hope that helps 
DR

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## prakel

> I use one of these batteries because it has a charge indicator,a handle and it's not heavy
> http://www.amazon.co.uk/gp/product/B...?ie=UTF8&psc=1
> Anyway connect the leads and move upwind for 2.5 mins then disconnect the battery


How many colonies can you do on one charge?

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## The Drone Ranger

> How many colonies can you do on one charge?


Hi Prakel
I have two of these batteries but one would do the job
I am told the varrox is about 150W 
I have around 25 to treat 
Here's the calculator
http://ep.yimg.com/ty/cdn/sports-imp...drainCalc.html
here's a quick overview as well
http://www.youtube.com/watch?v=MKDdrmM4UqY
http://www.thebeebusiness.co.uk/varrox.php

Why two batteries well you can only safely drain a car battery to about 50% before recharge 
Leisure batteries are not so restricted but heavier

graph.jpg

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## prakel

Hi DR, thanks for the calculator link. Was just wondering about usage in some out of the way (badly chosen) apiaries. Not that I expect to be starting to use sublimation any time soon. Must say though that I did give the subject a second glance the other week when a UKbeek posted a video of a (Italian?) vaporizer which he uses, on Beesource.

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## The Drone Ranger

The little graph at the end of my last post is this years treatment (only about a dozen hives)
They are all getting treated but I am monitoring these ones for the graph
Bit small I am not too good getting things like this in the post

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## The Drone Ranger

the graph at the end of the last post is this year
I am treating them all but monitoring these 12 for graph

data.jpg
thats the floor counts the hive number is at the top 
compare the start drop with the treatment drop (hive 22 and 23 for example)
You need to click on the image to see the table

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## Daveoneflowers

Thank you all for being so helpful. Until I gain more experience I think dribbling is the way to go, but it seems its a bit soon??. Reading through the posts the knowledge you share is invaluable to newcomers, thank you.

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## Daveoneflowers

Hi, at the risk of sounding stupid what is sublimation??????.

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## Daveoneflowers

Hi, this is why I am so interested. Found out about it on an American site where it seemed very popular an effective. In America they sell a unit that looks a bit dangerous for 175 dollars. I'm going to try and design an effective safe unit. I don't feel I can completely give up on the idea. Your post was a gem.

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## Daveoneflowers

Thank you exactly what I wanted to know. What is the success rate like compared with dribbling.

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## The Drone Ranger

> Thank you exactly what I wanted to know. What is the success rate like compared with dribbling.


There's a lot of opinions on that one 
I prefer the varrox and two treatments, preferably when the cluster has opened up a little
There's no science to back that, it's just a way of getting things done 
If you dribble (and lot's of posters here do) then once has to be enough   :Smile:

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## Jimbo

Hi Dave,

Sublimation is where a solid turns instantly into a gas usually by heat. Not all chemicals will sublimate but in the case of oxalic acid when you heat it to a high enough temperture it will produce a gas that will fumigate your hive and when the gas cools will turn back to a solid

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## Daveoneflowers

Cheers

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## beejazz

> the graph at the end of the last post is this year
> I am treating them all but monitoring these 12 for graph
> 
> data.jpg
> thats the floor counts the hive number is at the top 
> compare the start drop with the treatment drop (hive 22 and 23 for example)
> You need to click on the image to see the table


DR, am I reading the graph right, hive 22 had a pre-oxalic natural drop of 23 a day, and after one treatment, a drop of 298?  And hive 23, 3 natural drop, and a whopping 908 after treatment?  If so, since most of my hives are dropping between 0-4 a day, it will definitely be worth treating to get that amount of mites out of the hive ready for next year.  Thing is, i still have brood in some hives, judging by biscuit chewings on the insert.

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## nemphlar

Masks like SCOTT PRO2 with A1B1E1 filters are designed for organic acids
You might use something cheaper but at about £20  it is worth it if you are considering bent tubes and blowlamp madness

Working back to the last sub zero days I did mine today as well. I use the open 15 mm copper tubes and blowtorch although I did spend on a good face mask and eye protection.
A quick brush of the clearer board, set this aside and a 2 inch eke in place with a glass cover. The pipe through the side of the eke, heat for minute, the gas solidifies quite quickly after it cools on entering the top of the hive and falls onto bees and frames as fine powder, doesn't appear to be a lot escaping.
I do wash the kit after along with my woolly hat and veil and coverall just in case standing to windward has not been enough. Although keeping the blow torch on in today's gale was more of an issue
They don't seem overly disturbed by the process

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## gavin

Trickled mine and the association's today.  One apiary (the one mostly with full colonies that were at the heather) has colonies that are strong but light.  The others are fine and have better levels of stores.  More in the blog.

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## Daveoneflowers

> Masks like SCOTT PRO2 with A1B1E1 filters are designed for organic acids
> You might use something cheaper but at about £20  it is worth it if you are considering bent tubes and blowlamp madness
> 
> Working back to the last sub zero days I did mine today as well. I use the open 15 mm copper tubes and blowtorch although I did spend on a good face mask and eye protection.
> A quick brush of the clearer board, set this aside and a 2 inch eke in place with a glass cover. The pipe through the side of the eke, heat for minute, the gas solidifies quite quickly after it cools on entering the top of the hive and falls onto bees and frames as fine powder, doesn't appear to be a lot escaping.
> I do wash the kit after along with my woolly hat and veil and coverall just in case standing to windward has not been enough. Although keeping the blow torch on in today's gale was more of an issue
> They don't seem overly disturbed by the process


Sound like its the way I would do it, on the wing. Cheers

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## The Drone Ranger

> DR, am I reading the graph right, hive 22 had a pre-oxalic natural drop of 23 a day, and after one treatment, a drop of 298?  And hive 23, 3 natural drop, and a whopping 908 after treatment?  If so, since most of my hives are dropping between 0-4 a day, it will definitely be worth treating to get that amount of mites out of the hive ready for next year.  Thing is, i still have brood in some hives, judging by biscuit chewings on the insert.


Yes Beejazz
Natural drop is a good guide but not reliable I think
I treat twice because where would those 298 mites have been if the queen was to lay a patch of a couple of hundred cells

Hi Nemphlar 
I'm a bit cowardly so wouldn't chance my luck with a blowtorch  :Smile: 
Good instructions though

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## Pete L

> Must say though that I did give the subject a second glance the other week when a UKbeek posted a video of a (Italian?) vaporizer which he uses, on Beesource.


That would be me......
http://www.youtube.com/watch?v=Bby6r1qWxys

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## The Drone Ranger

Hi beejazz
I meant to say the inserts were cleaned on the 16th Nov late in the day
The natural drop represents 4 days ie the day of treatment was the 20th Nov
so you would be dividing the natural drop by 4 
The next count is 1st Dec some dropped 900 mites some lots less 
then about a week later 9th Dec they got checked again
Tomorrow I will count the mite drop and see how it's going
I'm looking at it the infestation level in the apiary with the stack bar

Counting hundreds of mites means marking off squares on the board but also no wind so not every day is suitable

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## gavin

> That would be me......
> http://www.youtube.com/watch?v=Bby6r1qWxys


Thanks Pete.  You can see that the face mask is very necessary if you don't wish to dose yourself with the stuff.  What a palaver though.  Step one, get a vehicle right up to your beehives - not possible in around half of all the apiaries I've visited.

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## prakel

> That would be me......


 :Smile: 





> ....Step one, get a vehicle right up to your beehives - not possible in around half of all the apiaries I've visited.


There's some great advice regarding this problem on the 'Honey Paw' equipment website




> As a rule, during snowless periods you should be able to park your car that close that you must be careful not to knock over the closest hive.
> If you need handcarts you have done something wrong.


...Something ELSE that I've done wrong.

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## Pete L

> Thanks Pete.  You can see that the face mask is very necessary if you don't wish to dose yourself with the stuff.  What a palaver though.  Step one, get a vehicle right up to your beehives - not possible in around half of all the apiaries I've visited.


 Done over 600 treatments with this equipment, 30 seconds per hive, continuous (no waiting for cooling between hives) multiple treatments can be used, three or even four, five to seven days apart if brood present..(three treatments seven days apart is the recommended dosage, but i find five days more efficient due to the varroa life cycle and phoretic stage) no harm or upset  to the bees or brood observed in any way, and of course no opening of hives,  we use a small lightweight  generator and long extension lead to power the device, so no need to get vehicle right up to beehives, although most of our hives are placed for easy vehicle access for ease when loading/moving/de-supering  them, but as i said, we use a generator anyway. The equipment is only supplied for 240v.

The equipment is also expensive, certainly not worth buying it for treatment of half a dozen colonies, but there are of course cheaper passive evaporators for that, i would certainly not go down the bent copper pipe and blowtorch route, no accurate control of heat.

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## prakel

Looks like a first class piece of kit -not going to rush into anything yet because trickling seems to be holding ground for us on our small quantity of colonies, but it has made me think about the possibility in a way that I hadn't done previously.

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## Pete L

> Thanks Pete.  You can see that the face mask is very necessary if you don't wish to dose yourself with the stuff.


 I have never heard of anyone who has been killed by using oxalic sublimation on bees, but i just hear the story going round...is there a list any place of these beekeepers who have been killed treating their bees, any names.

 Of course i think only an idiot would sublimate oxalic without proper proper breathing masks etc.
Did find this research a while ago, how accurate it is, i don't know, i am not a scientist.

http://tinyurl.com/yaxszga

Evaporation of oxalic acid - a safe method for the user?
T. Gumpp, K.Drysch, M. Radjaipour, P. C. Dartsch (2003)
Last modification: 02.02.2006 | Size: 330 kb | Type: PDF
http://tinyurl.com/yaxszga

...

Result: All measurements clearly underneath exposure-limit

Evaluation of data led to a clear result: None of the 20 participating
beekeepers reached even half the exposure-limit of 1.0 mg/rn3. (tab. 1). The
average value of the 10 measurements on evaporation procedure was 0.23
mg/rn3, the average value of the 10 measurements on spraying procedure was
0.22 mg/rn3. There was no significant difference between both methods (fig.
1).

To better comprehend these results we must briefly concern ourselves with
the definition of the exposure- limit (MAK-Wert): The exposure-limit is in
such a way selected that for an employee no health damage is to be expected
if he stays 8 hours a day during a working life time at working places at
which the alr concentration of the respective hazardous substance doesn't
exceed the exposure-limit [4].

Thus, based upon the presented data, a commercial apiarist could use oxalic
acid treatments during the whole year 40 hours a week without damaging his
health.

Meaning of the results to apiarist's practice With evaporation- and
spraying-procedure of oxalic acid, beekeepers have possibilities of
treatment against varroatosis whose effectiveness and bee compatibility have
already convincingly been proven [11]. However, there were concerns that in
particular the evaporation procedure was injurious to user's health.

Overcautious scientists therefore warned about evaporating oxalic acid or
recommended preventive measures which made the procedure unpractical, e.g.
wearing ABC protection equipment. The presented study dispelled reservations
against both procedures concerning possible health risks, appropriate
application presupposed.

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## The Drone Ranger

That's very reassuring Pete thanks for the link
I'm sticking with the mask but only when disconnecting the battery
It seems that even then that's overkill, just holding breath is good enough  :Smile:

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## Rosie

It's a shame they did not compare sublimation with trickling.  When I first looked into using oxalic acid I remember reading a report that German beekepers were starting to link oxalic acid with a cluster of cancers.  I can't remember where I saw the report but although nothing was proven I decided to stick with trickling as it had been well-researched by then and was shown to work effectively.

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## Pete L

> I remember reading a report that German beekepers were starting to link oxalic acid with a cluster of cancers.


Be interesting to see any report that links the cause of death directly to oxalic acid.

Don't some beekeepers have there smokers stuck in their mouths in Germany.

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## gavin

Hi Pete

This paper considers the risks of beekeepers using oxalic acid, more the risks to the consumer than the beekeeper and it seems fairly relaxed about them:

http://www.ema.europa.eu/docs/en_GB/...C500015217.pdf

Not much sign of the carcinogenesis mentioned earlier.

So, OK, no signs of death to beekeepers caused by oxalic acid, but damage to mucous membranes and kidneys is possible.  In the hands of the experienced beekeeper who has taken the time to understand and use appropriate safety measures needed, it should be OK.  But as something to be discussing as an option for people new to this, I can see no justification for doing anything other than pointing people to the safer option.  There just aren't enough benefits of vaporizing/evaporating/sublimating to justify the (smallish) risk.

In Scotland we have perhaps 3000 beekeepers.  If we promoted sublimation to them (as has happened in the past) then mistakes will be made by someone.  It is a lot harder to damage yourself or others with trickling.

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## gavin

If anyone is curious about what oxalic poisoning may be like, try this.  Can't see the end of the story so I don't know if he made it.  Of course, oxalic acid in syrup carries its own dangers - particularly of someone ingesting it.  In this case the solution will have been a lot stronger.

http://www.nejm.org/doi/full/10.1056...84402070300104

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## Rosie

I am told that at our concentrations it tastes like lemonade.  I always stress to my beginners that they should dispose of any remaining liquid in case a child gets hold of it.  It's probably not safe for the bees after a year in any case and also very inexpensive so it's not worth the storage space.

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## The Drone Ranger

If you are using the Varrox there's not much chance of problems 
I'm more worried by Caustic Soda or Acetic acid
I once rubbed my nose through the veil when doing a thymol treatment
It got a bit red and peeled like sunburn (the nose was nearly as bad )
The wedding was ruined 
I'm too clumsy for formic  :Smile:

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## nemphlar

DR It's a it of an odd winter so far with the mild weather, allowing for the gales and flooding. You had mentioned giving a second OA treatment, have you done that before.
I had count up to 380 and am tempted to treat again using the sublimation method
Regards John

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## The Drone Ranger

> DR It's a it of an odd winter so far with the mild weather, allowing for the gales and flooding. You had mentioned giving a second OA treatment, have you done that before.
> I had count up to 380 and am tempted to treat again using the sublimation method
> Regards John


Hi Nemphlar

I always do two winter Oxalic treatments with the varrox
https://drive.google.com/file/d/0B4k...it?usp=sharing
that link might work  :Smile:  its a graph of this year so far you can zoom in on it
Just in case here's a couple of jpg screenshots not so clear I'm afraid
Screenshot from 2013-12-28 15:39:13.jpg

Screenshot from 2013-12-28 15:40:19.jpg

So second treatment is now done and I will carry on counting
No 11 is probably in some trouble but will wait and see how it goes


This is a link to another graph from 2008/9

https://docs.google.com/document/d/1...thkey=CP2F0pIK

That was monitoring more hives (22) this year I am just counting some (12) because it's a pain in the butt standing in the freezing cold counting  :Smile:

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## nemphlar

Thanks DR I was able to open them, although the iPad isn't very clever at expanding, so some of the dates were a little difficult to read. I'll give another dose, that'll be 16 days between, is there any thought on the gap, I'm not clear if mine have any brood although the clearer boards are cold, so a little bit of hit or miss

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## The Drone Ranger

> Thanks DR I was able to open them, although the iPad isn't very clever at expanding, so some of the dates were a little difficult to read. I'll give another dose, that'll be 16 days between, is there any thought on the gap, I'm not clear if mine have any brood although the clearer boards are cold, so a little bit of hit or miss


The way I go about it is to use the stacked bar graph 
The drop* before* treatment begins is a sort of base line ( about 5 days drop or so)
After treatment I just monitor the drop 
When that gets back to the baseline value (give or take a bit) then I do the second treatment
In 2009 that was after 5 weeks 
This year it was 20th Nov till 26 Dec again about 5 weeks
Monitoring continues and hopefully ends with next to no drop 
That might be about 4 or 5 weeks after the second treatment

There are lots of theories about when to treat 
For instance 3 weeks after first frost etc I just ignore all that stuff
Hope that helps  :Smile:

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## gavin

> ... although the iPad isn't very clever at expanding, ...


I don't own one but I have played with one.  Presumably you've tried the two finger pinch (and reverse pinch or two finger spread) and the three finger tap!  Some of these work on my non-Apple laptop pad thing.

http://www.dummies.com/how-to/conten...interface.html

I too ignore the frost plus x days business DR (although last year I think I still did this).  It would be too easy to miss the best time and delay until brood raising really got underway.  Clearly there is some sort of drive to get brood raising underway as the days lengthen again, and that is coming very soon.  Does anyone really know if winter brood raising is stimulated by fresh pollen or stored pollen, nectar or syrup/fondant income, short or longer bursts of higher temperature?

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## Rosie

...or increasing day length?

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## The Drone Ranger

Hi Gavin
Old  E P Jeffree wrote that he could find brood any Winter month in some proportion of the hives, and he was in Aberdeen, which isn't noted for mild Winters  :Smile: 
I think they just have an instinct for replacing some of the bees that die and there is on and off laying possible during any Winter month

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## prakel

> Hi Gavin
> Old  E P Jeffree wrote that he could find brood any Winter month in some proportion of the hives, and he was in Aberdeen, which isn't noted for mild Winters 
> I think they just have an instinct for replacing some of the bees that die and there is on and off laying possible during any Winter month


I know that I'm in the far south compared to you guys but I reckon you're probably right DR, at least, you (definitely) would be if you lived where my bees live.

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## nemphlar

Thanks for that
I've treated them today for good or ill, that's 16 days since last treatment, with counts down to 20/50 for the last week.
It's a lovely still sunny day here and I was tempted to check for brood after the discussions, bottled it in the end and just settled for a OA treatment and a top up of sugar bag
Ps did the 5 nucs as well

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## Feckless Drone

I carried out my treatments yesterday, and was so tempted (but resisted) to check for brood. Nucs are down to 4 small seams of bees and hives also 4 & 5 but larger seams.
I had a small colony with Q mated in late august (not planned) that I thought might not build up but doing OK by the looks of it. All colonies still had good level of stores as judged by weight and can see sealed stores but I still put fondant over the cluster.
Wary of talk about early spring - we still have snow, ice and Siberian winds to come. Remember last year there was heavy snow in april.

Major lesson from last season for me was not to mark/clip Qs too soon, serves no purpose really. I did this to a swarm that arrived in the bait hive - after seeing the Q was laying beautifully. RESULT - Q disappears in the following week, leaving a couple of Q cells, probably due to my interference.

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## Jon

> Major lesson from last season for me was not to mark/clip Qs too soon, serves no purpose really.


April is a good time to mark and clip queens as the colonies are not fully developed and the queens are easy to find.
The main disadvantage is that you could have missed an autumn supersedure queen.

I have done the same as you in the past FD, clipped too soon and found the queen cells on the next inspection.
I have clipped hardly any of mine this year but will do them all in the spring.

I still have 8 apideas with queens although it is a couple of weeks since I have checked for signs of life.

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## snimmo243

I went down yesterday to treat with oxalic a few things struck me: one colony showed no varroa, the other 61! before treatment and 2 weeks of monitoring. Both colonies were very loosely clustered with 6 and 8 seams respectively, both had sealed stores at the top of the frames and they were both fairly active coming up to the top for a wee keek at us!

I just had a look back at my Varroa counts for my colonies, colony 1 (with the higher counts) seems to have rocketed - Using the beebase calculator these are the results i got for total mites in colony:
30/07/2013 -	40
07/08/2013 -	30
01/09/2013 -	45
11/09/2013 -	140
18/09/2013 -	100
04/01/2014 -	1700

Steven

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## Black Comb

Did you use thymol in the autumn?

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## snimmo243

Hi Black Comb
I didn't treat in the autumn as I followed the Beebase advice that comes out when you use the calculator which said treat in 10 months!
Maybe won't do that again  :Frown: 
Steven

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## Jon

I don't rate that beebase dropcount at all. I suppose it must give a very rough guide.
The best way to estimate mites is to take a sample of 300 bees and shake them in icing sugar to get a mite count.
The sugar dislodges the mites.
Can't do that at this time of year though.
I have had colonies with a low natural drop produce hundreds when treatment is applied.
I treated all of mine with Oxalic about 2 weeks ago. Some dropped only 1 or 2 mites whereas others dropped 100+

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## snimmo243

I will be going back in a week to check the count after treatment yesterday, it will be interesting to see what has been dropped

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## mbc

> I don't rate that beebase dropcount at all. I suppose it must give a very rough guide.


I agree.  I would go further and say it would be better not to publish it at all rather than mislead people to such an extent.  The problem is that despite the caveats that go with the varroa calculator people tend to overlook the massive margin of error and take the "estimated" numbers as gospel as its published by the NBU and therefore they expect the content to be factual.
FWIW I like to dust a few colonies with icing sugar and measure the drop, early in the season before there's enough drone brood to sample.  I'm shy about letting on about the dusting though, just in case word gets out I'm using it as a varroa control !

And none of my colonies are getting oxalic this year as I trialed treating some and leaving others last winter, the latter group getting on much better on the whole, though one apiary needed a remedial spring treatment with thymol.

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## snimmo243

I think from now on I will revert to pen and paper and do the calculation myself.  What is FWIW by the way

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## mbc

Oops ! I just read back a page and saw post#60.  My apologies, I wasnt referring to you as "people", just generalizing.

Its the extrapolating from natural drop thats iffy rather than the beebase calculator per se IMHO.
FWIW = for what its worth

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## nemphlar

I'd go so far as to say that natural drop counting is pointless, there are too many variables and whatever treatments you use, the winter OA treatment is always worth doing whatever your seeing in the lead up

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## gavin

> I'd go so far as to say that natural drop counting is pointless, there are too many variables and whatever treatments you use, the winter OA treatment is always worth doing whatever your seeing in the lead up


Perfectly agree (FWIW!).  Some colonies drop few mites yet harbour a fair load (how do they hide the mites?!). A heavy fall of mites on the board is bad news, a light one shouldn't make you complacent.  Sampling drone brood in a few places or powdered sugar rolls or similar are more reliable.  And ... that calculator is naive.  There are so many factors that can affect the build-up (or lack of it).  Various resistance mechanisms in the bees, sudden influxes from other colonies, maybe even pathogens of the mite.  The NBU should have it heavily surrounded by caveats, and they don't as far as I can see.

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## marion.orca

> I think from now on I will revert to pen and paper and do the calculation myself.  What is FWIW by the way
> 
> Sent from my C5303 using Tapatalk


FWIW - even I know that one and I don't text, own a mobile etc etc - For what it's worth [ I think !]

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## Jon

> And none of my colonies are getting oxalic this year as I trialed treating some and leaving others last winter, the latter group getting on much better on the whole, though one apiary needed a remedial spring treatment with thymol.


I have one apiary of 10 colonies which got no thymol in autumn after sampling showed very low counts but I am not confident enough to skip the oxalic as well. One dropped 100+ after oxalic so that makes it worthwhile.

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## mbc

My thinking is that its easier to treat colonies with a bad dose of varroa in the Spring than it is to resurrect them once they've been killed off by a midwinter oxalic drench.  To my mind the autumn treatment to give them a relatively 'clean' brood cycle or two of winter bees is the one not to miss.  Another case of swings and roundabouts I suppose.
I also tolerate quite a few varroa, its the only way I can think of to pick out the colonies to breed from who still thrive despite a bit of mite load.

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## Jon

Our thinking in the Irish varroa project was to try and breed from the colonies which maintain a lower than average mite load as opposed to those which can tolerate a large one. Part of the proposed methodology is to treat all or treat none in an apiary so as to maintain a level playing field in terms of collecting the mite count data subsequently. We still have not thrashed out the best way to do this as noone wants to stand back and watch colonies succumb to mites when they could be treated and saved then requeened.

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## mbc

IIRC The Kefus model is to pick out the top 10% most likely candidates to James Bond* for further evaluation and to treat the other 90% but requeen them with the progeny of the most resistant stock ASAP.  The disadvantage is you need hundreds if not thousands of colonies to play with to give yourself a decent chance of positive outcomes.
I realise by minimally treating the whole lot and picking the best to breed from I am merely selecting for bees which thrive under my particular management style, but I can live with that.
My issue with the system outlined for the Irish varroa project is that there can be various reasons for colonies to have low or high mite counts, some of them outside the scope of whether the colony is a good one or not.  This misdirection cannot take place if you are simply looking for healthy, vigorous colonies, thriving without any further attention than the others have had.

*live and let die

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## Black Comb

> Our thinking in the Irish varroa project was to try and breed from the colonies which maintain a lower than average mite load as opposed to those which can tolerate a large one. Part of the proposed methodology is to treat all or treat none in an apiary so as to maintain a level playing field in terms of collecting the mite count data subsequently. We still have not thrashed out the best way to do this as noone wants to stand back and watch colonies succumb to mites when they could be treated and saved then requeened.


Jon
Do you use natural mite drop to evaluate the initial mite load?

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## Black Comb

> And none of my colonies are getting oxalic this year as I trialed treating some and leaving others last winter, the latter group getting on much better on the whole, though one apiary needed a remedial spring treatment with thymol.


I'm trying the same this season. I have only one colony with a largish drop (at the moment) so was considering a shook swarm, but thymol is another option.
Any views about using MAQS as a spring treatment?

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## mbc

Nicked from a PeteL post ont other place :

..Sublethal effects and retarded growth, permanent damage to internal organs.
http://www.nand.be/ambrosius/nieuws/oxaalzuurtest.pdf

Effects on brood.
http://www.ibra.org.uk/articles/20080612_119

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## mbc

> Any views about using MAQS as a spring treatment?


Depends on how early, formic needs reasonable temps to be effective but it can also kill queens if its too hot, between a rock and a hard place if you ask me !
I have found a thin smear of apiguard applied on card directly over the brood nest (repeated in ~10 days)surprisingly effective at clearing varroa in the spring.  Its done the job for me in the past with no issues, so if needs be its what I'll use again.

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## Black Comb

Thanks mbc. 
Never treated in spring before so I will give it a go. Safer than formic.

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## Adam

I used MAQS on one hive in spring last year - no harm done.

I treat with thymol in late summer and oxalic acid in winter whatever the mite fall which some might think is an overkill.  I have to say that my oxalic drop this year has been the lowest I've measured. Although if 30 mites fall now as a result of treatment and they would otherwise double every month that's a lot of varroa by August!
Jan: 30
Feb: 60
March: 120
April: 240
May: 480
June: Too many

What I will be considering is to breed from stocks that have a low count as part of my selection criteria - assuming that they are in some way a little hygenic and remove some of the little buggers themselves.

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## greengumbo

Playing devils advocate....could you be selecting for Varroa that cling on / avoid bees cleaning behaviour, rather than "hygenic bees" ?

Lots of low counts pre-treatment this year across the country.

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## beejazz

Klingon varroa, omg.  I had low counts during summer and pre-apiguard, but am getting just about the normal amount, for me, after Oxalic.

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## nemphlar

After last years extended brood less period which seemed to wipe out a lot of mites I was tempted to try and create the same again, but spring and August just don't seem like the right time.
The small winter clusters were a concern although they pushed on really quickly.
ps any betting men care to give odds on the hobby beekeeper finding the mite resistant bee, I'd stick to treating them

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## mbc

> ps any betting men care to give odds on the hobby beekeeper finding the mite resistant bee, I'd stick to treating them


No one would give you odds, its already happened in places.

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## gavin

> Klingon varroa, omg.


Easy to spot these ones. The ridged foreheads and pugnacious nature are a dead giveaway.

mbc beat me to it - it has been done.  At least part-done.

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## Jon

> Jon
> Do you use natural mite drop to evaluate the initial mite load?


Mite count is measured by taking a sample of 300 bees from the brood nest and shaking them in icing sugar in a shaker to dislodge all the mites.

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## gavin

Full instructions for this project are available on the NIHBS website:

http://nihbs.org/eventsworkshops/ire...oring-project/

Given that there are many beekeepers taking part, this seems like a decent way to score potential resistance to me.

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## Jon

Unfortunately the funding for the DNA part of the project at Galway has fallen through for the moment so the search is on for another source.

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## gavin

Pity.  However just the empirical breeding bit may make good progress given what people have seen elsewhere, then provide material for snazzy genetics work later.

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## gavin

> Playing devils advocate....could you be selecting for Varroa that cling on / avoid bees cleaning behaviour, rather than "hygenic bees" ?


I wouldn't have thought so GG. Grooming is something that Varroa will have had to face on Apis cerana too.  It probably came pre-selected and hard wired for all it could do to cope with grooming behaviour as avoiding grooming would be central to survival for the mite.  But you never know .....

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## Pete L

> Playing devils advocate....could you be selecting for Varroa that cling on / avoid bees cleaning behaviour, rather than "hygenic bees" ?
> 
> Lots of low counts pre-treatment this year across the country.


 Open mesh floors may be helping towards the natural selection of stronger mites, weaker mites, ones that could of otherwise of just crawled off the floor onto another bee, been less aggressive, as they only slowly amble around, and even lost the use of, or grow less legs, now fall out through the mesh floor, thus removing them and their weakness from the gene pool, leaving only stronger more aggressive mites, ones that may of grown extra legs to hang on even better...so best look out for nine armed/legged mites with extra large biceps.

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## Adam

> Playing devils advocate....could you be selecting for Varroa that cling on / avoid bees cleaning behaviour, rather than "hygenic bees" ?
> 
> Lots of low counts pre-treatment this year across the country.


Possibly. I was (pleasantly) surprised by the low drop this winter. Maybe I am over-worried by varroa.

I have to admit that I haven't looked for 9 legged varroa yet. However Norfolk is where it will start as everyone outside the county seems to think that we are in-bred and have six toes so having odd mutations is natural to us!

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## fatshark

Varroa are always inbred … it's inevitable if you mate with your son.

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## Calum

Latest advice in Germany is trickle method works best between 0*C and -3*C as the bees are better bunched making the treatment more effective that the (till now recommended) +3*c temperature. This was on the basis of a comparative study of over 300 colonies, so will be verified before the medical treatment documentation (the oxalic treatment is classes as a vet medicine here) will be changed...

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## mbc

> Varroa are always inbred  it's inevitable if you mate with your son.


Not necessarily if there are more than one foundress mites in a cell, and isnt it the siblings who normally mate ?

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## gavin

> ... and have six toes so having odd mutations is natural to us!


Friends' daughter (Scot-SW England hybrid, no Norfolk involvement at all!) had 6 toes.  The requirements of modern shoe manufacture dictated that one was removed at a young age.

Yes, the Varroa virgins have a shortish time window to mate with their brother (or a less or unrelated male if the cell had more than one foundress).  AFAIK (FWIW!) mums have missed the chance once their sons are at large in a cell.

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## nemphlar

[QUOTE=Adam;23469]Possibly. I was (pleasantly) surprised by the low drop this winter. Maybe I am over-worried by varroa.

I had thought last years low counts were due to the Long brood less period a lot of beeks had seen. I had read somewhere last year that phoretic mites failed after 3 months and dropped off. Can't find it, beginning to wonder if I imagined it.
Wondered if at a convenient time of the year the queens might be induced to stop laying for a similar period

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## The Drone Ranger

Two treatments are more likely to reduce the numbers than one
I have had to settle for one trickle treatment on the 4 Paynes Nucs I am taking through Winter
Its pot luck to some extent whether you get a really high kill rate, so you have twice the chance of nailing them by treating twice
If you are trickling in Winter then your Autumn treatment is more crucial (there is a very good chance of a broodless period then as well)

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## snimmo243

I checked on my two colonies yesterday having used the trickle method last Saturday - the colony that showed 0 natural mite drop over 14 days prior to treatment dropped 300 in 6 days whilst the other colony showing 61 in 14 days = 4.4 per day or 1700 total dropped....  Wait for it 1400 in 6 days post treatment!!!

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## nemphlar

[QUOTE=The Drone Ranger;23489]Two treatments are more likely to reduce the numbers than one
I've tried 2 treatments this year, 2weeks between them, 3 weeks after the first of them I had totals of 350 to 500 mites the last 7 days, the 4th week, I have counts between 0 and 8.
DR do you always treat twice, might be a regular option all this assuming they come through the winter
Ps should mention this is across 6 hives

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## crabbitdave

I've also got 0 mite drop on my hives it been like that all year, I thought it may something to do with late spring, I even went to the lengths of having someone else check my floor boards, so I wasn't sure if treat them or not I've tried different method's each year, what do guys recommend ?

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## The Drone Ranger

[QUOTE=nemphlar;23492]


> Two treatments are more likely to reduce the numbers than one
> I've tried 2 treatments this year, 2weeks between them, 3 weeks after the first of them I had totals of 350 to 500 mites the last 7 days, the 4th week, I have counts between 0 and 8.
> DR do you always treat twice, might be a regular option all this assuming they come through the winter
> Ps should mention this is across 6 hives


Hi Nemphlar
I always do two treatments in Winter 

Hi CrabbitDave
Snimmo243 post #99 shows that even with a zero natural drop there is likely to be some there
Treating is the lesser of two evils usually and any varroa that are there will be gone, otherwise you might need to treat in Spring or Summer which is a more difficult time because of brood and honey.

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## crabbitdave

I think your right and it's always better to safe than sorry with this mild winter too it's all a bit strange, am going to try the Oxalic Vaporiser and see how it go's and try not to gas myself in the process, I'll let you all know how go's  




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## snimmo243

I take it if you don't report back we've to assume you have gassed yourself :0

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## Neils

> I've also got 0 mite drop on my hives it been like that all year, I thought it may something to do with late spring, I even went to the lengths of having someone else check my floor boards, so I wasn't sure if treat them or not I've tried different method's each year, what do guys recommend ?


While I don't believe in drops on the board as an accurate indicator (when there is no active treatment ongoing), if you've got to this stage, doing an autumn Thymol and now a winter OA treatment and are still seeing not mites drop I would not be too inclined to treat any more.

Keep an active eye out for Deformed Wing Virus (DWV) in the spring and moving into the active season and selectively uncap drone brood once it starts to appear and then act accordingly  then rinse and repeat next autumn, having monitored during the active season.

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## crabbitdave

Hi neils, I will look out for it, I would also say I was doing sacrificial drone comb on my hives and found no mites there either, and there no other keepers near me so I don't know if that's helped too


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## Feckless Drone

[QUOTE=The Drone Ranger;23503][QUOTE=nemphlar;23492]

I always do two treatments in Winter 

DR - just to confirm I understand. Is this two oxalic acid treatments 2 weeks apart? Perceived wisdom/advice given is that only a single OA trickle should be given but I like the idea of a spread to optimise chances when less brood or even no brood around.

FD

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## beejazz

I think DR fumigates not trickles...I would like to trickle again given that I suspect there is some brood, but dare not, most hives chucked out a number of dead bees after trickling a few weeks ago.  So once is enough, and will check varroa drops in a few months time.

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## The Drone Ranger

[QUOTE=Feckless Drone;23512][QUOTE=The Drone Ranger;23503]


> I always do two treatments in Winter 
> 
> DR - just to confirm I understand. Is this two oxalic acid treatments 2 weeks apart? Perceived wisdom/advice given is that only a single OA trickle should be given but I like the idea of a spread to optimise chances when less brood or even no brood around.
> 
> FD


Hi FD
I use the Varrox vapouriser for the two treatments
I don't know if it's safe to use trickle more than once 
I would say definitely not two weeks apart because that would be double dosing all the bees 

When I am treating with the vapouriser what I do is measure the drop for a few days
Treat the bees with the vapouriser
keep checking the drop again every few days
When the drop returns to the start value I treat for a second time
That seems to take about 5 weeks so the second treatment is about 5 weeks after the first
2013_14.png
This year it was 20/Nov/2013 and 26/Dec/2013
This line graph shows the effect

Screenshot from 2013-12-28 15:40:19.jpg
This was a stacked bar posted earlier and it shows the point where the drop came down to approx the start point 
There is no science here it's just a way of getting things done
There's no point in treating again if the first treatment is still killing them
The second treatment is intended to nail the wounded and any survivors from the first attack  :Smile:

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## gavin

Just a few comments.

This business about two treatments being better than one in a year like this one.  Go on - prove it!  I know that it sounds logical, but is there really a need?  Do the existing methods kill and drop mites over a protracted period already, perhaps covering a brood cycle, or not?

The existing treatments are optimised for efficacy vs damage.  One trickle treatment at the recommended amount causes mites to drop over a period of at least a couple of weeks.  It kills mites, it is dead easy, it goes directly on the bees and not all over the woodwork, it is really hard to damage yourself doing the treatment .... I'm happy to recommend it to folk and encourage them to use it.  It does have an effect on the bee population, slightly reducing numbers (10-15%?), and a second treatment would be unwise.

Gassing/vaporising/sublimating?  It is a weaker treatment, I think.  It seems to kill fewer bees if given in a single treatment.  As far as I recall (can't recall where I read it) it kills fewer mites too in a single treatment.  It goes on over all surfaces in the hive, you can repeat it and maybe improve its ability to kill as many mites (and bees) as trickling.  However it needs more equipment and it is undoubtedly (does anyone doubt this?) potentially more harmful for the beekeeper ... unless he or she really knows what they are doing and have the appropriate PPE.

This study (the one by J.D. Charrière, A. Imdorf, R. Kuhn (2004)) seems to show the milder effect on the bees of gassing, and shows a drop of mites (both trickling and gassing) over a fortnight or so, slower for gassing.  There is other Swiss research on this page that says some vaporisers are better than others.

What I am trying to say is that I'm unconvinced that there is much to recommend a second treatment in a season like this, except of course if you're using the less effective dangerous method, but why would you want to do that?!

The fact is that we need to keep on our toes anyway, as mite numbers can jump up for a variety of reasons, some of them unconnected with what we do to our own hives.  A mild winter may cause a generally bigger problem with mites in the subsequent summer (like the opposite last winter) but I'm not sure that changing the way we apply oxalic acid will help.

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## nemphlar

I take your point, everyone using sublimation should be familiar with the requirements and use of personal protection, if not don't use it. The sucrose method is very nearly foolproof, although someone will leave it in an unmarked vessel and someone else will drink it.
 All the articles I've read fail to show any consistent difference in effectiveness.
If you treat 2 weeks later and there is second small peak then it has killed more mites, which could be due to any number things from operator failure to brood in the chamber

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## Rosie

In my view probably all chemical treatments that burn or poison mites also have the same effect on bees. The trick is to give them the minimum amount of treatment to get them to your next planned treatment date. I find that a single light trickle usually gets them 12 months of protection and could not bring myself put them through the pain of an unnecessary 2nd treatment.

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## Pete L

> Gassing/vaporising/sublimating?  It is a weaker treatment, I think.  It seems to kill fewer bees if given in a single treatment.  As far as I recall (can't recall where I read it) it kills fewer mites too in a single treatment.  It goes on over all surfaces in the hive, you can repeat it and maybe improve its ability to kill as many mites (and bees) as trickling.  However it needs more equipment and it is undoubtedly (does anyone doubt this?) potentially more harmful for the beekeeper ... unless he or she really knows what they are doing and have the appropriate PPE.


 A higher % kill rate in broodless colonies with sublimation than trickling, one dose, but not a lot in it.

And this about the hazards..or not, read it and decide, i use a chemical warfare mask. The guys in the research in this link don't. It is right at the very bottom of the link also posted by Gavin...Evaporation of oxalic acid a safe way for the user. 
http://www.agroscope.admin.ch/imkere...x.html?lang=en

http://tinyurl.com/yaxszga

Evaporation of oxalic acid - a safe method for the user?
T. Gumpp, K.Drysch, M. Radjaipour, P. C. Dartsch (2003)
Last modification: 02.02.2006 | Size: 330 kb | Type: PDF
http://tinyurl.com/yaxszga

...

Result: All measurements clearly underneath exposure-limit

Evaluation of data led to a clear result: None of the 20 participating
beekeepers reached even half the exposure-limit of 1.0 mg/rn3. (tab. 1). The
average value of the 10 measurements on evaporation procedure was 0.23
mg/rn3, the average value of the 10 measurements on spraying procedure was
0.22 mg/rn3. There was no significant difference between both methods (fig.
1).

To better comprehend these results we must briefly concern ourselves with
the definition of the exposure- limit (MAK-Wert): The exposure-limit is in
such a way selected that for an employee no health damage is to be expected
if he stays 8 hours a day during a working life time at working places at
which the alr concentration of the respective hazardous substance doesn't
exceed the exposure-limit [4].

Thus, based upon the presented data, a commercial apiarist could use oxalic
acid treatments during the whole year 40 hours a week without damaging his
health.

Meaning of the results to apiarist's practice With evaporation- and
spraying-procedure of oxalic acid, beekeepers have possibilities of
treatment against varroatosis whose effectiveness and bee compatibility have
already convincingly been proven [11]. However, there were concerns that in
particular the evaporation procedure was injurious to user's health.

Overcautious scientists therefore warned about evaporating oxalic acid or
recommended preventive measures which made the procedure unpractical, e.g.
wearing ABC protection equipment. The presented study dispelled reservations
against both procedures concerning possible health risks, appropriate
application presupposed.

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## Pete L

*Honey bee treatment 'applied in wrong way'
Honey bee populations are being allowed to collapse because current treatments are being applied to hives in the wrong way, experts claim.* 




But a current treatment could kill up to 98 per cent of varroa mites in a hive without harming any of the bees inside if it is used correctly, and would offer a cheap and simple solution to the problem, experts claim.

Although oxalic acid is known to be deadly to the mite, it is often applied in quantities which are too low to be effective, or so high that it harms the bees as well as the parasite.

Now researchers have found that when applied as a vapour rather than a solution, and at a particular dosage, the treatment can remove virtually all traces of varroa from hives without any harmful outcomes for bees. 

 Results from the trials have not been officially published, but Prof Francis Ratnieks told the Telegraph that in the most effective format – a vapour at a particular concentration – the treatment was 97 to 98 per cent effective.

He said: “What we have found is that different methods do have different effects on the mites and the bees, but the best method does not harm the bees and is deadly to the mites.

“You would only have to use it once a year because if you knocked the mites down to a small proportion then they would take a long time to build back up again. It is very cheap, effective and easy to use.” 

Just from a news paper for now.....http://www.telegraph.co.uk/earth/wil...wrong-way.html

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## The Drone Ranger

I can't say much on trickle methods because I don't use them much
If like me it's OSR that is the main honey crop then its advantageous to get rid of varroa before Spring
I've posted the results of two treatments with the varrox
My advice on varroa would be measure the results of your treatments
Choose the method you believe is best and keep an open mind to other possibilities

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## Calum

Trickle method is tried and tested scientifically in Germany by various institutes, thats good enough for me...
Though I'd worry that the climate in Scotland would mean that colonies are seldom brood free (if at all), but this issue would apply to either treatment..

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## snimmo243

Just checked my counts again almost a week after my first post trickle counts, 660 and 50! Bees were flying as well

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## The Drone Ranger

> Just checked my counts again almost a week after my first post trickle counts, 660 and 50! Bees were flying as well
> 
> Sent from my C5303 using Tapatalk


Hi Simmo
here's the little table of results from my monitored 12 hives

Screenshot from 2014-01-16 11:35:02.jpg

If you can read it the hive number is the first row

No11 and No15 first treatment wasn't enough

No2 ,21 and 23 started with a count of 3 over a 4 day period ie <1/day 
Big difference in drops

No22 on the other hand looked like it would be bad with 23 dropped over the 4 days about 5 times more and yet after treatment it showed far less killed 
Treating that one a second time was unnecessary but proves they weren't just hiding in a batch of brood (I think)

No6 was a swarm that arrived 22 June 2013 and the bees are more like Buckfast or Italian X bees than Carnie X which would best describe the rest

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## snimmo243

Hi DR those figures are very interesting can you clarify that the figures are the total drop from the previous date in the table? Also you use the vaporiser? I used the trickle method, the interesting thing with mine is that the natural drop suggested a total population of 1700, so far, after oxalic I've knocked down 2000!

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## The Drone Ranger

> Hi DR those figures are very interesting can you clarify that the figures are the total drop from the previous date in the table? Also you use the vaporiser? I used the trickle method, the interesting thing with mine is that the natural drop suggested a total population of 1700, so far, after oxalic I've knocked down 2000!
> 
> Sent from my C5303 using Tapatalk


Hi snimmo

Yes I just count then clear the board ready for the next count
So the number is the drop since the previous date
It's good that your predicted count and the actual were so close
I think it can vary a lot if the count was only over a week or so
Natural drop might be more accurate over a month or more
Gavin mentioned the propolisers might deal with varroa better 
I have a couple of hives that love the stuff and it doesn't seem to have helped them

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## snimmo243

I've left the tray in the hive with heavy drop for another week to see how it goes. In the two weeks since the treatment the count has dropped by just over half so I'll see what I get next weekend then I will take out the tray for the rest of winter. Any suggestions for a spring treatment? Obviously temperature and impending supers will be an issue?

Steven

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## crabbitdave

Great news everybody after doing  Oxalic Vaporiser 3 days ago my mite count is still zero, am going to check after another 4 days but am really pleased to have been so lucky  :Smile: 


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## snimmo243

Show off 

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## crabbitdave

> Show off 
> 
> Sent from my C5303 using Tapatalk


Na mate just lucky 


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## snimmo243

I'm calling for a black bee sanctuary in the dale

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## crabbitdave

They will burn me at the stake I've got very calm and productive buckfast cross, am not one for black bee club am just happy if my bees are happy and more happy if their mite free 


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## Pete L

> Any suggestions for a spring treatment? Obviously temperature and impending supers will be an issue?


 Oxalic sublimation, three treatments, five to seven days apart, no worries about temperatures, try and do it before supering, but no problems with regards residues if not.

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## gavin

> Oxalic sublimation, three treatments, five to seven days apart, no worries about temperatures, try and do it before supering, but no problems with regards residues if not.


Pete, what do you mean by 'no problems' - good quality lab results for many different comparisons of sublimated and non-sublimated?  This technique generates a fog of oxalic acid crystals that settle out over the inside of the hive.  Do the bees remove all traces of this before they store any honey?

A Scottish bee farmer (no names please) who used an oxytetracycline treatment in autumn 2009 was still having problems with this antibiotic appearing in samples in 2013!  Oxytetracycline was promoted in 2009 as a safe means of staving off EFB problems (for a while) that one season only and residues were said to be impossible as it has a half life of 14 days in honey at 34C.

G.

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## Pete L

Oxytetracycline is not a natural ingredient of honey, oxalic is.

Many foods contain oxalic, and our bodys, even substances like hive clean contain oxalic, and this can be trickled on the bees at every exmination during the active season if desired, same as some beekeepers just trickle oxalic during the active season with no residue problems. 

There is some research, cannot find it right now, but they sublimated oxalic for several days and residue limits were below the legal permitted limits.

There is one here but not the one i am thinking of,and this was in winter.

During the heating about half of the oxalic acid disintegrates into harmless carbon dioxide and water. The
other half vaporises and forms fine drops and dusts of oxalic acid that precipitate on the bees and
everywhere in the hive. In a special research project this precipitation was examined to see if there were
any risks for the apiarist. Possible by-products of the vaporisation were also examined to see if they were
toxic. The results have indicated that any doubts about safety can be dispelled. Therefore we would like to
present the results and the new method of vaporising oxalic acid.


Solubility of wax and residues in honey
Oxalic acid is not water soluble. This is a most important fact when considering a use free of residues.
In the year 2000, the spring honey of colonies that were not treated with oxalic acid was compared
with honey of colonies in which different amounts of oxalic acid were vaporised. The honey harvest
took place at the same time in nearby apiaries.
The content of oxalic acid in the treated colonies was between 22,8 and 37,7 mg/kg honey (fig. 9).
Each column represents the content of oxalic acid of a collective sample of at least nine honey combs
from two or three colonies. The colonies that were treated with oxalic acid on average had a lower
content of oxalic acid in honey than the non-treated colonies. The vaporisation of oxalic acid,
therefore seems to be completely harmless in this respect too.
The content of oxalic acid in the examined honey samples was in each case in the lower area of what
is know as natural variation. Franco Mutinelli 3) looked at the natural content of oxalic acid in 32
samples of different Italian honeys. He found a content of 20 to 400 mg oxalic acid per kilogram
honey.
(


http://www.honeybeeworld.com/diary/f...a.de_engl2.pdf

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## snimmo243

> They will burn me at the stake I've got very calm and productive buckfast cross, am not one for black bee club am just happy if my bees are happy and more happy if their mite free 
> 
> 
> Sent from my iPhone using Tapatalk


It looks like I've set up a varroa sanctuary but mine are pure breeds  :Smile: 

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## Black Comb

I'm beginning to think this sublimation job may be worth serious consideration. Seems like a very flexible option.

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## Beefever

Actually I was thinking the same.  Is it worth the risk of getting a whiff of that stuff though or putting un-gloved hands in a hive if it is used mid season.  Worth considering though.

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## snimmo243

Latest drop 287 in 9 days

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## snimmo243

How long after oxalic trickle treatment would you consider the mite drop to go back to natural
Steven

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## gavin

Interesting question - some data shows it takes a long time.  Maybe a dense cluster with bees quiet in cold spells takes weeks, whereas an open cluster with more active bees takes less time?

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## snimmo243

I had a count of 5 per day pre treatment, 1 week after treatment 233 per day, 1 week later 110 per day,  1 week later 35 per day, going to count again tomorrow to see if drop reduces again

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## snimmo243

My drop count today was down to just over 9 per day

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## nemphlar

> My drop count today was down to just over 9 per day
> 
> Sent from my C5303 using Tapatalk


Must be a big colony to survive a bug load that size

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## snimmo243

When I did the trickle on 4 Jan there were 8 seams of bees, as I said earlier I'm the thread the counts in Autumn were no too bad but the pre treatment count in Jan showed an explosion in mite numbers, I'm a bit concerned 

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## nemphlar

Fair enough that is on the larger side

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## snimmo243

I hope it stays that way! Artificial swarm in March? :-)

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## nemphlar

Haha not many things are certain in beekeeping but march queen mating in Scotland is a definite no

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## snimmo243

> I hope it stays that way! Artificial swarm in March? :-)
> 
> Sent from my C5303 using Tapatalk


With our weather the same could be said of May June and July 

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## Little_John

> Solubility of wax and residues in honey
> Oxalic acid is not water soluble. This is a most important fact when considering a use free of residues.


NOT water soluble ?  Bit of a typo there, methinks ...

I've been using OA sublimation for years - it's dirt cheap, much quicker to apply than trickling, and providing you stand upwind, completely safe. I've never used a mask or any other form of protection - there's no need, providing you understand and respect the chemistry.

The BIG difference between trickling and sublimation - which is a difference which is rarely focussed upon - is that trickling is usually done with OA dissolved in a weak sugar solution. So, as the bees lick off the sugar solution, they will be ingesting OA at the same time. 
With sublimation, the fine dust of micro-crystals is not attractive to the bees in any way, so it will not be ingested in significant amounts. But - due to it's hygroscopic nature, the fine crystalline dust forms clumps around the feet of any varroa, thus causing the mite's demise, but because of a difference in anatomical structure, the feet of bees are immune from such clumping.

To my mind, and for numerous reasons, the use of sublimation in preference to trickling is a no-brainer.

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## drumgerry

Curious to know why you think sublimation is quicker than trickling.  Takes me about a minute or less to trickle oxalic on a box of bees.  And another good reason to trickle rather than sublimate is surely cost.  Trickling only needs a syringe which costs pennies and there's no need for the required sublimation apparatus which is a significant cost surely.

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## Pete L

> Curious to know why you think sublimation is quicker than trickling.  Takes me about a minute or less to trickle oxalic on a box of bees.


Gerry, takes me 25 seconds, or less with 1g of oxalic, for sublimation.

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## Rosie

Wow that's impressive.  That means you could do an apiary of 10 colonies in a fraction over 4 minutes.  It takes me that long to get my boots and veil on.

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## drumgerry

Fair enough Pete.  The point I was trying to make though is that trickling is not a long winded process!  It's (almost!) idiot proof and couldn't really be cheaper.  Buying one of those fancy Varrox things and using a car battery to operate it can't really be said to be cheap.  And even if you're using a diy vapouriser I'd be amazed if the cost was less than a plastic syringe - mine is currently still in use 4 years down the line as I clean and dry it thoroughly after every use.  If people want to sublimate/vapourise again fair enough but to say it's a better method than trickling is stretching it a bit in my opinion.

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## Pete L

> Wow that's impressive.  That means you could do an apiary of 10 colonies in a fraction over 4 minutes.  It takes me that long to get my boots and veil on.


 It is fast Steve, good when doing a lot of colonies, but the equipment is expensive compared to the passive evaporators.

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## Little_John

> Curious to know why you think sublimation is quicker than trickling.  Takes me about a minute or less to trickle oxalic on a box of bees.  And another good reason to trickle rather than sublimate is surely cost.  Trickling only needs a syringe which costs pennies and there's no need for the required sublimation apparatus which is a significant cost surely.


Overall, cost is a lot cheaper than using a solution - which isn't cheap to purchase and has a sell-by date. 

On the other hand - 1 kg of OA costs about a tenner, IIRC - that's for a thousand treatments, and without any expiry date.

No need to buy Varrox kit - it's easy enough to make your own gear. I'm currently making another one for a friend - I use a 50 watt soldering iron element attached to a large brass washer - the apparatus itself is contained inside a wooden box which has a computer fan attached to it's removable top and an exit hole for the vapour to exit at it's bottom. The box is then simply placed over any hole in your crown board.  They cost about a fiver to make. Using a low thermal mass washer means that the heating-up time is minimal, and the cooling-down time is equally minimal, thus speeding up the operation.  Not that speed is a major issue for me - thoroughness is far more important.

I have seen DIY efforts which use a fairly substantial milled aluminium block - but heating such a mass requires both a large wattage heater, and is very s l o w  to operate.

But the main reason I use sublimation is: less disturbance to the bees; 98% (or thereabouts) mite knockdown with just one application; no dribbling of water all over a colony of bees (which they do not like); and there's no inadvertent feeding of OA to the bees in the process, as would be the case with trickling.

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## drumgerry

Who said anything about buying solution?!  Don't most of us who trickle make it up ourselves?  A set of digital scales already purchased for kitchen/home brewing and bob's your proverbial.  And you've not convinced me that Varrox or all that DIY shenanigans is cheaper and it's certainly not easier than my 4 year old plastic syringe.  As to disturbance again not convinced - a minute or less and using lukewarm solution and the bees don't stir from their cluster unless the air temp is warm as it was when I did it this new year.  Even then there were only a couple of fliers.  Not seeing the harm generated by your ingestion theory either.  So again as far as I'm concerned oxalic by trickle or sublimation is equally valid.  Either way we're inflicting a dose of acid on the bees.

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## Pete L

> Who said anything about buying solution?!  Don't most of us who trickle make it up ourselves?  A set of digital scales already purchased for kitchen/home brewing and bob's your proverbial.  And you've not convinced me that Varrox or all that DIY shenanigans is cheaper and it's certainly not easier than my 4 year old plastic syringe.


I used to be one of the biggest proponents of trickling oxalic as a treatment, and wrote the recipe on various places back when the use of oxalic was rather frowned on by many, used over 840 doses and then changed my views on it, and i never bought any ready up made solution, but it is obviously an easy way for some. Never used an ordinary syringe, used the multi dose type which i get on the farm, this with a pipe connected to a two L plastic milk bottle containing the solution, but either way it does the same job, just faster when treating lots of colonies. Cost as far as i am concerned is insignificant and does not really come into it, sublimation/trickling,  when compared to the other costs like several tonnes of fondant and sugar, 50 or 60 tonnes of cedar, thousands of sheets of wax...etc, and that against the sale of bees,queens, tonnes of honey....the treatment costs are just miniscule, almost zilch really.

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## mbc

> No need to buy Varrox kit - it's easy enough to make your own gear. I'm currently making another one for a friend - I use a 50 watt soldering iron element attached to a large brass washer - the apparatus itself is contained inside a wooden box which has a computer fan attached to it's removable top and an exit hole for the vapour to exit at it's bottom. The box is then simply placed over any hole in your crown board.  They cost about a fiver to make. Using a low thermal mass washer means that the heating-up time is minimal, and the cooling-down time is equally minimal, thus speeding up the operation.  Not that speed is a major issue for me - thoroughness is far more important.


Sounds good, any chance of pictures or plans ?
I was impressed with the equipment that PeteL uses, but balked at the price, as I'm only thinking about dosing the odd swarm and perhaps having another tool in the locker for firefighting problems as they become apparent in the season.

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## Little_John

> Who said anything about buying solution?!  Don't most of us who trickle make it up ourselves?


Well, I've never trickled so can't comment - but bee forums often have people asking about use-by dates and HMF/safety issues and so forth. The advice they always get is "chuck it away and buy new". And as it's sold by nearly all beekeeping suppliers ... that suggests somebody's buying it ! 




> [clip] So again as far as I'm concerned oxalic by trickle or sublimation is equally valid.


Although they both use the same acid, they are not similar procedures at all. 

Think: if you were given a bottle of lotion - clearly marked "for external use only" - to apply on your hair to eradicate a bad case of scabies, would you proceed to dilute it with sugar water, take a bloody great swig of it, then sprinkle a little of it on your hair and hope for the best - or would you rub it all into your hair instead, as per the label's instructions ?




> Either way we're inflicting a dose of acid on the bees.


No, we're not - and that's the whole point I'm trying to convey. I do not treat bees for ANYTHING, and haven't done so since I first started back in '59. If they should die from disease, then that's an appropriate end for a genetically weak colony, or perhaps as a result of unsuitable housing. If it should be the latter, then I must change some aspect of what I'm doing, or learn to live with the consequences. That may sound a hard approach to have adopted perhaps, but no different from that of the old skep beekeepers who kept bees for many hundreds of years without the use of any 'medicines'.

I repeat - I do NOT treat bees. I only treat the mites, as they are not a 'bee disease', but a parasite. Sure, the bees remain 'in situ' when the mites are being subjected to their fatal treatment, but any take-up of the oxalic acid by the bees is both minimal and purely accidental, and as small amounts are naturally present in honey, any very small amounts added to it via open cells are undetectable.

At the risk of offending anyone, which I assure you is NOT my intention, I would suggest that the technique of trickling OA may actually be part of the ongoing problem with Varroa, rather than part of it's solution, for trickling MUST always be hit-and-miss, with bees at the top of the inter-comb space getting wet, but some of those below staying dry. Thus, some bees are not being treated, with some mites surviving to then reproduce their species.

To my mind, the only effective way to treat with OA solution would be to remove each frame in turn and spray both sides of the comb - only then could you be certain that the vast majority of bees have been brought into contact with the solution. Such a method would then certainly be fairly comparable in efficiency with that of sublimation/vapourisation, but the time taken to administer by spray would then be what - 20x longer, at least ?





> MBC: Sounds good, any chance of pictures or plans ?


Sure, I'll cobble something together - I've got some pics (somewhere ...) of an early prototype during construction.  I think your approach - to have such kit handy in case of an outbreak - is very sound. Of course 3 doses, a week apart, are required during the season, but I suspect you already knew that ...

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## drumgerry

Not looking to get into an argument here.  Generally it's not how we do things around here.  You've pitted your opinion against mine and who's to say which is right.  Both equally valid so not much point in going round the houses.

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## Rosie

For what it's worth I know of nobody who buys ready-mixed oxalic acid solution although some obviously do otherwise the traders would not stock it.  The problem with mixing your own is the resolution and accuracy of the scales.  My wife's kitchen scales have a resolution of 5 grammes and an unknown accuracy.  My own honey scales are retail approved and have a resolution of 2 grammes.  Hence I use my honey scales but I would not attempt to mix less than a kilo and often 2 kilos so that I can be confident of my proportions.  Locals with only a couple of hives usually cadge my spare solution or that of other beekeepers.  None of us would keep it for the next season. The biggest cost to me is the sugar.  In fact I just have enough crystals left for one more year after about 8 years of treatment with a pack that cost me £7 at the time.  I only use about 12 or 15 mls of mixture per colony though.

Claiming that applying oxalic is a varroa treatment and not a bee treatment seems a cop-out to me.  The targetting might be reasonable but in essence the only difference between treating with oxalic acid and, say, antibiotics for foulbrood, is the size of the pathogen.  Mites are a bit bigger than bacteria.  I think all treatments should be kept to a minimum which, in many cases, means no treatment at all.  3 treatments a week apart would not suit my style of beekeeping at all.

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## drumgerry

Re accuracy of scales I have a £20-ish set of digital scales and when I first got them I measured them with known weights and they were pretty much spot on.  Happy to use them for oxalic solution making and I'm making usually around a litre at a time.  I certainly would never keep the solution after use and can't imagine anyone doing so.

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## Jon

I have a digital scale I bought new on ebay for under a tenner which is accurate to 1/10 gramme.
It weighs up to 300g.
Anytime I need some oxalic solution I make it up fresh in the ratio of 7.5g Oxalic, 100ml water 100g sugar.
It takes about 5 minutes each time.
You can check the accuracy with a 2p piece which weighs 7g.

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## drumgerry

What he said

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## Little_John

Ok - while I'm searching for my old pics, here's a diagram to be getting on with. 

http://i57.tinypic.com/14l6duh.png

Although brazing would be best, JB Weld is good enough - as it's rated for 260 deg C continuous, or 300 intermittent.

The brass washer is supported by steel wires run to the box sides, and which also support the deflector. The OA is held in one of those aluminium containers which normally hold night-lite candles, so by using several of those, multiple doses can be measured at home - which is one less job to do on site.

I think that's about it.

I'm sure an even simpler device could be designed, using a 12v soldering iron to which a copper plumbing 'end-cap' is bonded, again using JB Weld. Drill a hole in the side of the box to take the soldering iron handle, which would then be a self-supporting platform. The deflector could then be attached to the removeable lid with steel wires. You'd then fill the end-cap directly with OA, as with the Varrox.

You'd need to ensure that the soldering iron would never exceed 300 C (260 C for safety) - this could be done with a simple rheostat and a £4 Chinese temperature meter.

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## Little_John

> Claiming that applying oxalic is a varroa treatment and not a bee treatment seems a cop-out to me.  The targetting might be reasonable but in essence the only difference between treating with oxalic acid and, say, antibiotics for foulbrood, is the size of the pathogen.  Mites are a bit bigger than bacteria.  I think all treatments should be kept to a minimum which, in many cases, means no treatment at all.  3 treatments a week apart would not suit my style of beekeeping at all.


Those who give antibiotics do so in such a way that they are ingested (otherwise they wouldn't work). 
Dribbling OA in sugar solution encourages the bees to ingest OA.
Vapourisation is a topical application, where ingestion is highly unlikely.

If you can see no difference between these techniques, I would ask you not to consider drinking sun-tan lotion, as it's not really intended for internal use ...

If 3 treatments are too much then just give one .. in winter.  

Or give none at all (many beeks are now adopting this philosophy) - but be ready with the kit just in case varroa should suddenly flare up in your apiary. The alternative is to - maybe one day - watch thousands of bees die in front of you, in the full knowledge that you could have done something to prevent it.  There are sound reasons why people wisely install fire extinguishers and sprinkler systems in their properties.

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## Jon

> Or give none at all (many beeks are now adopting this philosophy) - but be ready with the kit just in case varroa should suddenly flare up in your apiary. The alternative is to - maybe one day - watch thousands of bees die in front of you, in the full knowledge that you could have done something to prevent it.  There are sound reasons why people wisely install fire extinguishers and sprinkler systems in their properties.


Best practice is to be proactive and monitor varroa levels by taking a sample of 300 bees and then doing a sugar shake or alcohol wash to calculate the percentage of mite infestation.
You can then decide whether to treat or not without being caught out by any mite level 'flare up'

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## Jimbo

I use the trickle method purely on health and safety grounds. If you were to do a risk assessment on the chemical you would find that oxalic vapour is more of a hazardous to the operator than oxalic acid in liquid form. If you want to look at more of the hazards of working with Oxalic acid then go to the Sigma Aldrich Biochemical web site and look up their safety sheets

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## Rosie

> Vapourisation is a topical application, where ingestion is highly unlikely.


I would expect the vapour to condense on every surface of the hive, although preferentially on the coldest ones.  These surfaces probably include every crook and nanny on the bee's surface: eyes between the claws, mouthparts etc.  How do they get it all off again?  How do they get it off the hive and cell walls? Do they use a wire brush and vacuum cleaner or do they lick it off?

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## mbc

> , here's a diagram to be getting on with. 
> 
> 
> Although brazing would be best, JB Weld is good enough - as it's rated for 260 deg C continuous, or 300 intermittent.


Thanks for that.  Whats JB weld ?

Edit: Ahh! I just googled it and its a bit like araldite, would that transfer the heat suitably ?

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