Oxalic - how does it kill varroa

[gavin]

Erratum: The paper linked is actually the 2007 one by R. Martín-Hernández, M. Higes, J. L. Pérez, M. J. Nozal, L. Gómez and A. Meana, and not the 2003 work where Nozal was the lead author.

Well spotted itma, you are quite right. The Nozal paper was the next one up the list that my search unearthed.

Boca: yes, the document you found describes killing Varroa by putting 10 of them in a tube with dried oxalic acid, but that doesn't prove its mode of action in a colony. I'm still unaware of proof that it is the outside of the mite that takes the hit in colonies of bees treated with oxalic. The only direct evidence of an effect on arthropods is that affecting the internal organs.

.
i remember Gavin. You are sharp scientist. Many hats and hair will be splitted on sharp head.

I've just checked and my head is still more or less round and certainly not sharp. The hair is thinning, but the hats are few.

And previously:

it is sure that oxalic does not make a bee poisonous to the mite

It is sure that that dogmatic statement is unjustified.

Listen to Hivemaker: that man speaks sense.

G.

 

[For want of a better word]

Ummm.
Actually the orthodoxy seems to be that any weakening of the bees *is outweighED BY* the benefits - ie the treatment is an overall benefit.
Not the other way round, as you have (surely inadvertently) posted!

Well possibly not, but thanks for the correction... like Finnman English is not my first language!!!
...but I do understand your apostrophe rule!

Still not biting the bullet about vaporisation !

 

[For want of a better word]

Originally Posted by Finman View Post
.
i remember Gavin. You are sharp scientist. Many hats and hair will be splitted on sharp head.

 

[WI-USA-BEEK]

Randy Oliver - A great beekeeper

“ If you meand Randy Oliver as "scientific beekeeper", forget it. Has has done no researches about oxalic acid. “

Randy has done several trials with oxalic acid. Randy does trials with many varoacides. And the fact that Randy has not done "peer reviewed lab Work" to find why OA kills varroa and that you somehow think that the information he provides is therefore invalid or of no use is quite funny to me. If we were to then discredit all data Randy provides, then we must discredit everything you provide as well because you have done no scientific research yourself. Im not aware of you doing any trials either with control colonies.

Randy however has carried out many sound trials providing beekeepers with excellent data on the efficacy of many of the varroa treatments available.

-

PeterS – There has been a lot of trials on the effects of OA on wintering colonies. It does weaken them a bit according to the research of many who used untreated colonies for a control (a colony may come out of winter with 15% less bees than an untreated colony) but they recover quickly in spring and will be in much better shape than a colony infested with varroa.

-

Icanhopit – vaporizing OA is usually done in the summer months. It only affects the varroa mites on the bees and not in the brood so it has to be done three times on a weekly basis. The data I have read varies wildly on the efficacy it provides. The OA drip in early winter when the colony is broodless provides a much better kill. Randy Oliver has also done a study on vaporizing OA and info is on his website.

Queens seem to be unaffected by the OA drip. Theory as I think galvin stated is that the queen is fed by workers from secretions from glands in their heads so the queens do not consume the acid in the OA syrup.

Another handy treatment with the OA drip that can be done in summer that I plan on trying this coming season is on broodless nucs. I make splits by crowding the colonies my best queens head and make several nucs with the swarm cells. It is reported that if you do an oa drip in the morning when the bees are somewhat clustered or spray the solution on the bees in the short window where they are broodless right before the queen starts laying or right after she begins works very well. It supposedly has no effect on the young queens.

 

[gavin]

Agree with almost all of that WI, but over here vaporisation/sublimation is usually a winter treatment. It is quite effective, but given the additional hazards to the user many frown upon its use.

Dipping sounds trickier than a quick dribble, or even a quick spray.

G.

 

[Finman]

“ If you meand Randy Oliver as "scientific beekeeper", forget it. Has has done no researches about oxalic acid. “

Randy has done several trials with oxalic acid. Randy does trials with many varoacides. And the fact that Randy has not done "peer reviewed lab Work" to find why OA kills varroa and that you somehow think that the information he provides is therefore invalid or of no use is quite funny to me. If we were to then discredit all data Randy provides, then we must discredit everything you provide as well because you have done no scientific research yourself. Im not aware of you doing any trials either with control colonies.
.

HALOO AMERICA!

Europen varroa group have done 10 years very carefully reasearch work since 1998. There has been members of very acvanced beekeeping research countries like Italy, Germany, Denmark and Switzerland. These countries have very high food hygieny level too and they do not accept what ever results beeresearches give.

I know that in USA there are the best resources to reseach beekeeping industry antthere are lots of universities which do that.

The problem of USA is that the knowledge which USA produes seems to be valid from Florida to Alaska. Even hive models and beestocks are the same.

In Europe it means that we could use same methods and same bee strains from North Africa to Polar Circle.

About varroa..... Varroa has been longer in Europe and that is why Europe is 10 years ahead America in treament mehods.

All European varroa researches has been published in English, but somehow America like to use Randy Olivers writings than original varroa group researches. this year Canada took into use "officially" the methods which has been used in Europe 10 years.


And what Britain does? It byes from Italy 6% oxalic acid because the stuff has Euroan Union license to sell.
If you add to it water and sugar, and get 3% syrup, are you going to prison?
Then you cry that oxalic acid violates malphigian tubules.

i have followed Forum of Beemaster and of Britain about 7 years. I have not met mavy cleaver beekeepers on forum. They prefer to "have opinon" than clear out what is the reseached fact.

I have teached many years how to use trickling to boath great nations but it has been difficult. And I have given links to basic reseaches but but and but.

 

[Finman]

“ IRandy Oliver has also done a study on vaporizing OA and info is on his website.

vaporizing has been used at least 20 years. Perhaps Randy has not even bees when it was in common use.

British Dave Cushman has been very good person to deliver the beekeeping knowledge on his sides.
He had very short and trustfull information about important beekeeping issues.

 

[OXFORDBEE]

On Nanetti's slide the first picture is labelled as "ARTEFACT!".
He must have said something about that.

Indeed he does. Here is is reply when I asked him about the pictures:

The pictures you hint to come from a source claiming to explain the mode of action of oxalic acid against varroa mites. They were included in the presentation as an example of the several misleading pieces of knowledge spreading amongst the beekeepers, and as an introduction to a more serious approach to the question.

In that case, the so-called “proboscis” is a leg in the reality, and the depicted detrimental effect of the oxalic acid on the varroa exoskeleton an obvious falsification made by an unknown author.

The graphical processing I made according to a subtractive approach on the first two pictures produced the result shown in the second slide of the series. It accounts for a graphic removal of varroa hairs and ambulacrum by an unknown author, and this is why the third slide reports the writing “artefact” on the picture.

It may be interesting to know that anecdotes of this kind may spread uncontrolled also in a context where only verified scientific information is expected ( http://www.docstoc.com/docs/28392075/Effect-of-sonar-on-whales--Oxalic-acid---the-beekeepers-friend ).

Many thanks for your enquiry and best regards,

Antonio Nanetti

 

[For want of a better word]

Interesting debate.

My conclusion on reading all of this is that there is no scientifically peer reviewed answer as to the mechanism that the Varroa mite undergoes when treated to a dose of OA.

Trickling a 7.5% solution of Oxallic Acid dihydrate when the colony is broodless after a cold period ( mid winter) will kill varroa...... however here is conflicting reasoning.

It has been stated that OA by vaporisation only kills phoretic mites and therefore is a summer treatment as it will not eliminate varroa in the capped brood cells.

Why then is trickle administration carried out when the colony is broodless?
Is OA carried into capped cells?

(7.5% OA mix from Wally Shaw is 75g Oxallic Acid dihidrate mixed in 50/50 sucrose solution,, 1kg sugar to 1litre water) 5ml per seam of bees
solution should be at room temp 20 degrees centigrade... or is that Celcius degrees?

 

[oliver90owner]

Why then is trickle administration carried out when the colony is broodless?
Is OA carried into capped cells

Second is excluded by the first so it should never happen?

 

[stilllearning]

blimey what a lot of technical mumbo jumbo
my understanding is that it dissolves the mouthpiece therefore the mite dies of starvation i guess also it dissolves the hairs hence the reason you find some wriggling still and some dead. a few seasons ago a lot of my hives pratically drank the stuff, i didn't notice any effect on the bees , basically if i didn't put it on they would've died anyway.
all i know is i put it on...it works...thats good enough for me

 

[For want of a better word]

Why then is trickle administration carried out when the colony is broodless?
Is OA carried into capped cells

Second is excluded by the first so it should never happen?

Precisely !

I find the argument somewhat confusing......

Vaporisation only kills phoretic mites but trickle must be carried out when colony is broodless

Therefore why is vaporisation on a broodless colony not advised?

This is very confusing for me let alone a novice reading all
this!​

​

 

[oliver90owner]

Therefore why is vaporisation on a broodless colony not advised?

Who said that. Piffle.

 

[alanf]

7.5% OA mix from Wally Shaw is 75g Oxallic Acid dihidrate mixed in 50/50 sucrose solution,, 1kg sugar to 1litre water) 5ml per seam of bees

Is that a mistype? 75g of oxalic dihydrate in 1000g of water plus 1000g of sugar gives a 3.2% solution of oxalic by weight.

 

[OXFORDBEE]

Interesting debate.

My conclusion on reading all of this is that there is no scientifically peer reviewed answer as to the mechanism that the Varroa mite undergoes when treated to a dose of OA.

Trickling a 7.5% solution of Oxallic Acid dihydrate when the colony is broodless after a cold period ( mid winter) will kill varroa...... however here is conflicting reasoning.

It has been stated that OA by vaporisation only kills phoretic mites and therefore is a summer treatment as it will not eliminate varroa in the capped brood cells.

Why then is trickle administration carried out when the colony is broodless?
Is OA carried into capped cells?

(7.5% OA mix from Wally Shaw is 75g Oxallic Acid dihidrate mixed in 50/50 sucrose solution,, 1kg sugar to 1litre water) 5ml per seam of bees
solution should be at room temp 20 degrees centigrade... or is that Celcius degrees?

7.5% Oxalic acid solution is stronger than that actually required for varroa control see read this

I think you are a bit confused about oxalic acid treatments. All oxalic acid treatments work by contact. Delivery can be by oxalic acid sublimation or by use of a sugar syrup carrier. Mites in cells are protected by the cell capping and are not exposed to oxalic acid when treated, this might explain more.

Given the ideal time to treat with oxalic acid (or any other contact acaricide) is when there is no brood RABs comment is perfectly correct. Hower I'm wondering what you mean by capped cells? If you are talking about capped honey comb then the answer is no. Background levels of oxalic acid are not increased after treatment.

 

[For want of a better word]

Is that a mistype? 75g of oxalic dihydrate in 1000g of water plus 1000g of sugar gives a 3.2% solution of oxalic by weight.

or 4.5% w/w


Seems that this topic was covered this time last year.. and the year before

that...

Scientific Beekeeping . Com
4.2% w/v [ 3.5 % w/w } in 60% sucrose solution

Newton Abbot Beekeepers ???
3 to 5 ml of 2.8% w/w OA in 5% syrup per seam in first two weeks of January is another recipe

 

[JamezF]

“ If you meand Randy Oliver as "scientific beekeeper", forget it. Has has done no researches about oxalic acid. “

Randy has done several trials with oxalic acid. Randy does trials with many varoacides. And the fact that Randy has not done "peer reviewed lab Work" to find why OA kills varroa and that you somehow think that the information he provides is therefore invalid or of no use is quite funny to me. If we were to then discredit all data Randy provides, then we must discredit everything you provide as well because you have done no scientific research yourself. Im not aware of you doing any trials either with control colonies.

Randy however has carried out many sound trials providing beekeepers with excellent data on the efficacy of many of the varroa treatments available.

Not being familiar with his work, I am in no position to comment on his results and will not do so.

However, I do know that setting up trials is far more tricky than many people (some of whom ought to know better) think. The peer review phase is very good at teasing out situations where the trial has actually not been set up quite correctly and is not actually properly testing the thing the researchers think it is, or where results are misinterpreted as well as when the wrong conclusions are drawn from those results. Those problems do occur, even with the best-intentioned researchers.

I don't believe that research that hasn't undergone peer review is without merit, but I do think it's preferable and gives greater credibility to the work if it has taken place.

James

 

[For want of a better word]

Therefore why is vaporisation on a broodless colony not advised?

Who said that. Piffle.

Thanks for that Tractor Man... seems to be a lot of piffle about!

Lets get back to sensible topics.... top space vs bottom space!!

 

[OXFORDBEE]

Bedtime reading perhaps

 

[oliver90owner]

top space vs bottom space!!

Won't make any difference to trickling oxalic, or sublimation of same! Don't need to adjust the dose, the strength or the time of administering.

Sublimation is probably easier/simpler for this lot. Wouldn't have to adjust for RMMs of dihydrate and anhydrous acid (not easily envisaged when making it up as an aqueous solution, I suppose, by some).

They will get around to it in a few pages. Then the other thread will be resurrected, or another started.

Now there's a thought. When is 7.5 g of oxalic acid not 7.5g?

Perhaps we should call the oxalic threads 'wheelwright threads' they go round and round and keep rolling on...

But, you never know, this post might just jog some memories.