Help Oxalic Acid.

[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

[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.

[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

[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

[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..

[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

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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

[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!

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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