# OA Vapor & Dribble brood mortality



## [email protected] (Aug 1, 2004)

That is why I use the dribble in December. No brood in upstate NY. I like to use on a very cold day, 20 degrees or colder, and have never had any noticeable negative effects on bees.


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## johno (Dec 4, 2011)

Cloverdale I read a paper about 6 weeks ago, unfortunately I cannot remember where I read it. This paper compared dribble to vapor treatments and documented brood loss and at the end found that brood loss on the OAV compared to brood loss of the untreated control hives. So I believe that brood loss from OAV is negligeable. The responce one normally gets when refering to brood loss is normally from tests done by the dribble method. Most of acedemia have very little experience with OAV and just rattle off the so called common knowledge, besides OAV is only good for broodless bees as it kills only phoretic mites. Well well so does Amitraz only kill phoretic mites so if you would have OA crystals in the hive every 4 days it would do just as well as the amitraz based miticides


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## Cloverdale (Mar 26, 2012)

[email protected] said:


> That is why I use the dribble in December. No brood in upstate NY. I like to use on a very cold day, 20 degrees or colder, and have never had any noticeable negative effects on bees.


Good to know Llyod, thanks.


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## Cloverdale (Mar 26, 2012)

johno said:


> Cloverdale I read a paper about 6 weeks ago, unfortunately I cannot remember where I read it. This paper compared dribble to vapor treatments and documented brood loss and at the end found that brood loss on the OAV compared to brood loss of the untreated control hives. So I believe that brood loss from OAV is negligeable. The responce one normally gets when refering to brood loss is normally from tests done by the dribble method. Most of acedemia have very little experience with OAV and just rattle off the so called common knowledge, besides OAV is only good for broodless bees as it kills only phoretic mites. Well well so does Amitraz only kill phoretic mites so if you would have OA crystals in the hive every 4 days it would do just as well as the amitraz based miticides


I believe the University of Montana knows what they are talking about with such precise numbers; I’ll try and get the actual research for this. This University as you probably know is very reputable, with Dr Jerry zBromenshenk teaching part of this. I know that Rusty Burlew of Honey Bee Suite, Pat Bono of NY Bee Wellness, some of the Olivarez family have all participated in this course and have their Master Beekeeper Cert. from them. As for the Amitraz I would rather the OA than taint the comb wax in my hives. Thanks for the info though.


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## msl (Sep 6, 2016)

> I’ll try and get the actual research for this


The prof is referring to a dribble study HATJINA,HARISTOS 2005 
https://www.researchgate.net/public...stered_by_trickling_method_on_honey_bee_brood

Kevin O’Donnell's Individual Experimental Project for the UM master program found an 80+% drop in brood in 2/3s of the tested hives when they were given 3 weekly OAVs, but its a very small sample size and some queen loss that was unlikey OAV related, but mucks up the numbers 
http://doorcountybeekeepersclub.org/site/wp-content/uploads/DCBC-Mites.pdf
there have been a few "small sample size" experiments with OBHs showing young larva killed by OAV and quickly replaced with eggs that then hatch out and replace the lost larve while older larva wasn't affected as bad, suggesting damage may be easy to miss. To catch it (IIRR) they used color-coded dry erase markers on the glass to track the age range and caught on when post-treatment areas marked as young larva was younger then it should have been Ie should have been capped already 
I am not aware of any large-sized OAV brood damage trials, but what we have seen seems to be in line with the label and brood damage is a real possibility



> This University as you probably know is very reputable


kinda sort of?
some people feel the program is just short of a scam.... if you pay your $$, you pass No one has been denied their "piece of paper" if they paid the fees. 

I am bothered that the prof didn't bother to take the time to site the study, poor practice, poor teaching. Fits in with what I have been told by people who have dropped out, feeling they were wasting there time and money and weren't getting a good education... I know one "master" from the program who has never done anything more than walk away splits, how can you be a "master beekeeper" and have no queen rearing experience?


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## Cloverdale (Mar 26, 2012)

Actually our queen rearing program was modeled off of Randy Olivers and tested as such. Microscopy of tracheal mites and nosema levels which most of us know; varroa lifecycle, which is figured in hours, more accurate than days; how to do an appropriate oxalic acid VAPORIZATION, NOT DRIBBLE, which made me antsy it took him so long; 
splits their way; pollination; basic anatomy of honey bees (more indepth of just general); and of flowers, etc. I am looking forward to discussions of scientific literature, rankings of articles, whats bogus etc., and my least anticipated part of the course is Pesticides. The required book is Pollinaror Protection: A Bee &Pesticide Handbook by Carl A. Johansen & Daniel F. Mayer, we are required to read cover to cover. Its like one of those dreaded high school required reading books that you check how many pages it is (and I am a reader) This is one third of the grade, taught by Dr Bromenshenk and Cam Lay, whom I recognize from the Bee-L forum. So, as for MSL’s “master” thats too bad he is a knucklehead (not you MSL). I did ask for the research on the testing of killed brood study so I will post what is passed on. 
You are graded on participation in the forums and of course testing. If I thought this was a money only program I wouldnt be in it. I did check out Cornells but I wont say anymore about that.


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## little_john (Aug 4, 2014)

If Vapourised Oxalic Acid does indeed kill significant amounts of brood, then I'd expect to see bees hauling out at least some advanced-stage grubs - but I have yet to see any evidence of that happening after an application.
LJ


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## Cloverdale (Mar 26, 2012)

little_john said:


> If Vapourised Oxalic Acid does indeed kill significant amounts of brood, then I'd expect to see bees hauling out at least some advanced-stage grubs - but I have yet to see any evidence of that happening after an application.
> LJ


I dont think it was significant, but if open brood wouldnt they eat it? And I havent seen that myself either but Im thinking the more vulnerable eggs/ young larva?


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## johno (Dec 4, 2011)

The tests in MSL's post are completely contrary to the paper I read in the last 3 months, unfortunately I cannot remember where I read it. It was a Paper from some university and their conclusion was that brood loss by the colonies treated with OAV was compareable to the brood loss in their control colonies. I think that some of Randy Olivers test with OAV surprised him with the strengths of the colonies after I think 9 treatments 10 days apart. Personally I have never seen bees dying or colonies being weakened by OAV treatments and my colonies recieve at least 12 treatments a year.


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## Cloverdale (Mar 26, 2012)

I havent seen any unless, like I mentioned to little john, they eat them.


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## johno (Dec 4, 2011)

Cloverdale I used to treat my observation hive often and observe the results, maybe I would not see if workers were removing eggs but I would have noticed them removing or eating brood. Why they would remove eggs in the first place as I am sure that if open brood is not effected there is less likelyhood that eggs would be effected. Now the observation hive has 6 medium frames and I would treat them with a full 2 grams to look for adverse effects but found none.


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## Cloverdale (Mar 26, 2012)

You know, I just dont know what to think about this. This is being taught at college level by a reputable college and Professor.


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## AHudd (Mar 5, 2015)

Would this be something useful the Bee Health Guru device could solve? 

Alex


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## crofter (May 5, 2011)

I think someone made reference to mortality due to multiple dribble treatments and assumed it also applied to vaporization. This has been hashed out before but cant remember where that took place. If that truly applied to Oxalic Acid Vaporization it would be well known.


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## snl (Nov 20, 2009)

I, two years ago, had 2 single deep 9 frame test hives where the (marked queens) were held behind excluders on 3 frames. I’ve marked frames of brood and watched the development from egg to emerging bee. 
I vaporized those 2 hives EVERY time I’m went to the yard which was almost every week from March through October. I could find no harm to either the queens or brood during that time. 

That was all I needed to see as to whether OAV was detrimental.


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## msl (Sep 6, 2016)

> I just dont know what to think about this. This is being taught at college level by a reputable college and Professor.


The prof provided data from a dribble study(without telling you the method), did he send anything about OAV specifically? To Johno's point, its easy to find studies showing the brood is impacted by dribble, OAV not so much 

johno its still real early, as this is researched we will see contrary results till a trend emerges. like Dribble's impacts, its likely climate and genetics play a role, and it's likely a nonsignificant issue


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## Cloverdale (Mar 26, 2012)

AHudd said:


> Would this be something useful the Bee Health Guru device could solve?
> 
> Alex


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## little_john (Aug 4, 2014)

The bit I don't understand is *why would* VOA kill open brood ? Say two grams of OA is injected (I use just the one) - of that maybe 50% (say) ends up on the woodwork or attached to bees. That would leave around one gram spread over thousands of cells (which form a more-or-less vertical surface anyway - with the youngest of the larva tucked down well inside at the bottom of the cell. Larval food is acidic anyway, so how much more acidity would be generated by the few micro-xtals of oxalic acid which reaches it ?

Although I've never used dribble - likewise, I really can't see why that would affect brood mortality either. The cold liquid might, as might thermal exposure during the treatment - but not the OA itself. A puzzle.
LJ


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## crofter (May 5, 2011)

Drizzle with glycerine as the sticky moisturizer rather than sugar has promise as causing less ingestion by the bees. Glycerine tastes sweet to us but the bees dont like it. It would be far more expensive than sugar syrup so that is probably the reason this is not getting much traction. 

Maybe with vaporization they dont have to lick it off; they can just blow it off!

As far as an instructor being infallible...... well....., I would not give that a lot of weight.


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## johno (Dec 4, 2011)

Yes as far as the experts are concerned remember how many years the poor mites had to live off the bees Haemolymph before they were allowed to consume bodyfat. This paper I keep refering to went into the difference between drip and vapor in great detail using the standard sugar OA solution and there was a definite loss in brood with the drip method. I generally try to bookmarkany stuff regarding OA but sometimes the computer does and sometimes it does not but I am still racking my remaining brain cell and keep searching.


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## wildbranch2007 (Dec 3, 2008)

took me a while to find this bee-l search leaves much to be desired even when it does work. see #4 4 hours afterwards, all the larvae that had been floating in jelly were removed
see 1. at 3x the vapor dose, larvae from 3-6 days were sacrificed, but replaced with eggs within hours. 



> Subject:
> Why is Oxalic Acid Vaporization harmless?
> From:
> Ruth Zajicek <[log in to unmask]>
> ...


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## Robert Holcombe (Oct 10, 2019)

Univ. of Sussex, Brighton, England - multi-year studies, large hive counts, identified proper amounts to apply, OAV better hive performance than Dribble, winter double OAV with 14 day spacing and 99.7% (memory) efficacy, do not remember larva mortality, would if significant - oxalic acid is my choice with spinach, no sugar.


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## msl (Sep 6, 2016)

> Univ. of Sussex, Brighton, England - multi-year studies


"towards integrated control of varroa" 1-5 IIRR Toufailia EtAl



> OAV better hive performance than Dribble,


certainly what they said, not what their data showed 
Towards integrated control of varroa: 2)comparing application methods and doses of oxalic acid on the mortality of phoretic Varroa destructor mites and their honey bee hosts Toufailia EtAl 2016... more or less the OAVers bible, this is the study that popularized OAV and quantified its efivecness.
sadly they manipulated the test conditions and cherry pick the data they use in their conulsution and miss represent findings as significant 

as an example here is thier graft, shows dribble coming out on top at 2.25 







they kept the OAV wand hot (against the manufactures direction) dumped in the oa and slid it in to the hive all ready smoking to make OAV "faster"
and they they come out saying OAV is much "safer" for the bees when the difference between the two 2.26g treatments was 16 dead bees ... 16 bees out of a full hive 

sorry that one is a bit of a hot button lol, people say a lot of things about that study that just isn't true. OAV is GOOD stuff, but its not that much better, only a little 

Johno toss this one in your notes
someone finally did an efecintily study on high capacity OA devices, they did very very well compared to traditional pan heaters (witch suprized me) showing that whatever the break down is its not causing a loss of mite killing power, we shale see what the replacates look like https://www.albertabeekeepers.ca/wp-content/uploads/2018/09/2019-Final-OA-vapourizer-report.pdf


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## johno (Dec 4, 2011)

Msl, that does not surprise me as the control that one has and also the temperature information you get while sublimation takes place is far superior to wand technology. The often touted OA breakdown theory is a total falacy with the band heater vaporizer. One needs to know their vaporizer, sublimation temperature indicated is a gauge of the units efficiency provided the sublimation bowl with its thermocouple is light enough to show the quick change in temperature. I can show that the temperature will drop from above the 450's toaround 290 when all the conditions are correct and minimum sublimation time is then achieved, however with just a few microns of oxidization on the bottom of the bowl will find the OA subliming at330 degrees with a lengthier sublimation time but what is actually happening is that the OA is still subliming at the same temperature as in the first example but the oxidization layer prevents an immediate heat transfer. Also bear in mind that the OA sublimes to gas and water vapor and is already condensing into cryatals on the way out of the nozzle which I have proved and have produced a picture of the OA gathering on the hair






s of my arm at around 3" away so you can see why I say OA breakdown is a fallacy.


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## msl (Sep 6, 2016)

> The often touted OA breakdown theory is a total fallacy with the band heater vaporizer


Randy Oliver's current work suggests otherwise
and of course, I found why I felt the data was surprizing when I reread it, they weren't playing fair 


> The cumulative reduction in mite infestation levels of OA (efficiency) was 98%, 94% and 96% in colonies treated
> with ProVap, Varroa Blaster and Varroa Cannon, respectively. Across all application methods,*after four treatments*,


they are comparing 4 provap treatments to get to 98% against studies that used one pan heater treatment (witch has a 50% breakdown, but that counts the 30% or so of the locked-in water ) and got a 97.6% kill rate, dirty pool. 
It took 2 provap treatments just to hit a 90% or so kill rate 
Devil is in the details, as always and It makes you wonder what there was no control group... seems they went out to prove that the high cap systems kill mites... but many people can tell them that they do kill mites


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## johno (Dec 4, 2011)

In My opinion Randy Oliver is heavily biased against OAV, He once got a whiff of the vapor and is now convinced it is a dangerous material to work with. To make it even worse one of his B-L buddies had an accident with his vaporizer and had hot OA blown onto the face mask he was wearing so that did not help matters much. They will totally ignore the fact that some beekeepers are using only OAV and have been doing so for years with low over winter losses and mite counts. There is the old school that still teaches new beekeepers that mites can be controlled by IPM such as SBB and the Dowda method of sugar shake, and insist that OAV can only be used on broodless colonies during the early winter. Yet they still send their newbies to me to get nucs, so after a while you just give up and do your own thing as nothing changes except the needle to protect the record.


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## Steve in PA (Jan 26, 2015)

crofter said:


> Drizzle with glycerine...


The Glycerine Dribble Recipe

I have switched over to dribble. I read an EU study that made me comfortable with minimal brood loss. Another reason I'm comfortable is that Hiveclean and now VarroMed are approved for up to 11 treatments per year.

For me dribble is much easier than dragging out all the stuff for an OAV treatment. Just today I treated an outyard for the last time until I see a problem or pull supers. It's my 1st year switching exclusively to dribble so maybe I will see something that makes me change my mind. I started using it last fall and this is the best my hives have looked coming out of winter in the few short years I've been beekeeping.

If I find the study I read, an Italian one, I will post it later.


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## msl (Sep 6, 2016)

If you read up on it you will find VarroMed is ruffer on bees then standard dribble https://www.ema.europa.eu/en/docume...varromed-epar-public-assessment-report_en.pdf
its main advantage is it shelf-stable (unlike dribble) so it can be sold on shelfs, that means $$ to push it threw approvals, poof it can be used supers on


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## Juhani Lunden (Oct 3, 2013)

johno said:


> In My opinion Randy Oliver is heavily biased against OAV,


opcorn:


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## crofter (May 5, 2011)

Juhani Lunden said:


> opcorn:


Juhanni I am uncertain of what your emoticon implies...


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## Juhani Lunden (Oct 3, 2013)

crofter said:


> Juhanni I am uncertain of what your emoticon implies...


Well, here in Finland if someone makes popcorn and sits down, it is a symbol for waiting for the coming debate. Maybe a very interesting debate indeed...



(In this particular matter a debate about weather Randy Oliver is biased in his OA opinions.)


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## crofter (May 5, 2011)

Juhani Lunden said:


> Well, here in Finland if someone makes popcorn and sits down, it is a symbol for waiting for the coming debate. Maybe a very interesting debate indeed...
> 
> 
> 
> (In this particular matter a debate about weather Randy Oliver is biased in his OA opinions.)


Now we are on the same page. 

Randy is a great contributor to bee research. A lot of people gain from his easily understood explanations and his well controlled trials. I have not read his recent position on OA but remember thinking some of his earlier work did seem just a little bit over cautious. And I mean just a little. He is not in the position to be encouraging _cowboy_ behavior, so that is understandable.

I dont think many people convincingly argue against the effectiveness of OA during broodless conditions, but they needlessly give it a poor rating on phoretic mites due to the _silly recommendation of seven day interval treatment_. If mite load is high and brooding is ongoing much tighter schedules needed. 

As far as some larval brood mortality I have never noticed it setting back a colony; heavy mite load sure as heck will though! People deliberately instigate broodlessness so why the great handwringing over some minor larval mortality. There is very low colony resource investment in a larva at this stage _versus_ raising a full term bee compromised by varroa.


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## johno (Dec 4, 2011)

In some of Randy Olivers writings he has mentioned that he would not like to expose himself or any of his crew to the dangers of oxalic acid vapor, so he rates the dangers pretty high which is the reason I mentioned the bias. Which basically boils down to the fact that if he feels that it is an undesireable treatment he will not be giving it its due, which is just my opinion. There are also those who will judge OAV against Apivar in treatment for treatment which is entirely unfair as you are equating a miticide that is in the colony for 42 days against a miticide that is in the colony for only 3 days so I would stick my neck out and say that 10 treatments of OAV every 4 days will give you the same results as Apivar without even opening the hive.


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## Robert Holcombe (Oct 10, 2019)

"this is the study that popularized OAV and quantified its efivecness" - timing fits about when I dug-in, but that is not all that I looked at. I do like the critical, quesitoning comments. Europe was using OA dribble and OAV long before this time period, although OAV was late to the table. Italians did some interesting research - twice and influenced me. German field application safety study influenced me. I also go with Jennifer Berry's experience and decision resulting in selection of OAV (ABJ or was it Bee Culture?). Most opposition to OAV, I noticed, was fear of gases (and ignoring formic acid issues). This is not an issue for me and I notice Randy is changing his tune - pedal to he metal and all gassed up now. A fair amount of negative comments were put out there about OAV including by some research people. Besides I like the idea of attacking Varroa via deposition and horizontal spreading / contact. I get the competitive efficacy of both methods and a choice is typically made, few do both. 

I admit to lightly reading the statistical part but did notice your comment, so my memory tells me. A bit of publish or perish going on? But reports fail to explain the statistical models, sensitivity analysis of same and they name so many model - programs my head spins. So I have not dug into that mathematical rabbit hole. It has been four years since reviewing and searching about OAV. Probably time to do it again but I prefer working the humidity - temperature issues of a hive's enclosure as I have "cleaning" it down pat for now. 

Advantages of OAV from a novice's practical point of view;
1. OAV does not go through the gut of the bee like dribble does, takes a while, if I remember right, for isotopes to clear out of the bee when "dribbled" treated.
2. OAV cleans the hive too,  (is it possible?)
3. OAV treatments in Fall and Winter without exposing the cluster,
4. Efficient application , fast, apply practically anytime ( except with supers on - an unsupported requirement from what I can find - copy job of Canadian requirements) based on a temperature - efficacy related issue. (It helps to have a few acres, John Deere Mower with a trailer and a barn to be efficient.)
5. Can be used on packages, ( I do not buy them anymore but people I help do.)
6. Dribble has EPA limited number of application ( gut issue?) 
7. OAV is less concentrated per dose and but slower acting than dribble (but longer lasting?)
8. I now have a lot of observational experience OAV ( zero with dribble) - all good; nine for nine this year but a hive has a drone laying, 1st year, late summer Queen. 
9. I refuse to use "chemicals" like Amitraz here, treatment free was a disaster, OAV and drone culling with Varroa inspection / counts in drone cells as an indicator works well for me. OA is ubiquitous, half life is short and essential for bowel movements .
10. Christmas to early Jan. OAV treatment(s) works well here - no treatments until Fall robbing season; drone culling and inspection in between. I can Fall feed syrup while treating and supers are off - perfect timing.
11. In either case, we still do not know exactly how oxalic acid kills Varroa (still true?)
12. How are thoracic mites killed? Efficacy for either method? (Not enough money in selling oxalic acid?) 

Now that OAV is much more popular, I watch for new negative or supportive data as I can change my mind. I also make better observations now. The voting seems positive so far for OAV. In my area most do not use OAV but dribble as earlier comments about the dangers of OAV and wand cost drove newbies selection.


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## Robert Holcombe (Oct 10, 2019)

:thumbsup: I asked my MD internist about OAV. He asked if I eat it! As it is free choice and my memory is failing as well as the German study i often forgt to bring 1/2 mask. 

Funny the EPA never provided performance requirements for the 1/2 mask. I do wear wrap-around glasses or safety googles.


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## Robert Holcombe (Oct 10, 2019)

Selling tickets?


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## msl (Sep 6, 2016)

1- corect.. but dribble kills for 2 weeks not 2 days and going threw the gut may be bad for the bee, it seems to cause a shed of lineing cells to knock back nosema levels, espicaly in the next genuration 
2 never hurd that
3 yes... but the "recommended" effective temp range for dribble is lower than OAV, so you can treat in colder conditions. 
4 not really unless you drop $$ on a band heater system I can dribble a hive in under a min with a $1 syring and be back in the truck when treating a small yard before my band heater vap would have heated up
5 It can not by law, has to be dribble spray see label.... if you mean instaled packages dribble works just fine 
6 often said, but internet BS, see the EPA lable https://www3.epa.gov/pesticides/chem_search/ppls/091266-00001-20151013.pdf Now I wouln't hit winter bees 3x with dribble... but there is no need to.. there are commercial opps in other countries doing 8 a year
7 reverse OAV dubble deep dose is 2g, dribble is 1.75g oav kills for 2-3 days dribble for 2 weeks OAV kills a tad bit more when bloodless, dribble significantly more brood on do to its longevity catching mite as they emerge for a longer period of time. brood on single dribble kills as many mites as 3 OAV treatments
8 I don't think anyone is saying it doesn't work
9 Amitraz has a MUCH shorter 1/2 life
10 yep, but for the reasons I give in #1 and #7 I use dribble for my late summer knockback to fight the mite bombs (in low-pressure yards I can get by with a spring split and single winter dribble) and knock back nosema, then rotate to OAV for winter use to avoid negative impacts on the long-lived winter bees
11 correct
12 I am not sure many care



> Now that OAV is much more popular, I watch for new negative or supportive data as I can change my mind.


yep, that is the smart play 





> There are also those who will judge OAV against Apivar in treatment for treatment which is entirely unfair as you are equating a miticide that is in the colony for 42 days against a miticide that is in the colony for only 3 days so I would stick my neck out and say that 10 treatments of OAV every 4 days will give you the same results as Apivar without even opening the hive.


a fair argument, what is the difference between an extended-release strip constlily dosing the hive every day and aplying a treatment every 4 days? 
Aside from it being illeagle pestiside abuse(witch can change) the issue would be the over the top OAV users tend not to rotate treatments and stick with a single mode of action. Time and time again this has proven a poor plan against the mites, and indeed most pests.


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## johno (Dec 4, 2011)

Msl if you were doing that quick dribble in my yards I would expect you to be there for more than half the day and be pretty tuckered out when you are done as my colonies are that large that when I have removed my honey and start treatments most of my colonies are 3 boxes high, many have 4 boxes. My vaporizer will reach operating temperature in 2 minutes and while heating caps will go out onto the first 6 hives. The total time for a yard of 24 will be less than 25 minutes and I would not have had to spend maybe a half hour mixing up my dribble before hand. By the way I was born in the sub tropics so spent many years stomping on roaches and I believe the roaches have still not become resistant to being stomped on. As to whats legal or not I pay more attention to the laws of physics not so much the crap that comes out of Washington.


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## JWPalmer (May 1, 2017)

I was going to post something about repeated mechanical damage, ie, stomping, being a bit different than poisoning. I have not found a fly yet that was immune to a flyswatter.


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## crofter (May 5, 2011)

"Time and time again this has proven a poor plan against the mites, and indeed most pests." 

That is a broad statement about past happenings and not logically predictive of the future for this specific treatment. 

Firstly a resistance must be physically possible. It is not a guaranteed conclusion but it is often appealed to as such. There *are* some emotionally appealing analogies though. I think it is approaching 30 years of common use now with no signs of the development of resistance to OA. 

I have seen reference made to requiring more treatments now to control mites than a number of years ago but virus levels generally higher plus novel ones, are neglected for consideration as being the controlling factor there.

Amitraz certainly can and has shown itself prone to the development of resistance. With some treatments resistance development in the target is a very real scenario and rotations are generally a good recommendation. I am quite familiar with it in relation to animal wormers. There are two main categories of products for horses and we always rotate.

I dont bother rotating my 30.06, 308, and 6.5x55 for deer though. 50 years and no signs of resistance yet!


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## msl (Sep 6, 2016)

> I was going to post something about repeated mechanical damage, ie, stomping, being a bit different than poisoning. I have not found a fly yet that was immune to a flyswatter.


Follow studies, not internet experts repeating bad information 
current thinking is


> Oxalic acid is believed to immobilize calcium, thus impairing the calcium-potassium ratio in mite tissues


. this is from the registration for Oxybee https://www.ema.europa.eu/en/documents/assessment-report/oxybee-epar-public-assessment-report_en.pdf page 17
page 20 of the Varomed restration I posted earlier says the same thing 




> Firstly a resistance must be physically possible.


We know from Maggi EtAl 2016 that one population of mites was 7X more resistant to OA then the other showing there was a genetic component that might be selected for. 
The long and short is it unwise and incorrect to say it can never happen, it very well may, it may not. The loss of a product this cheap and effective would have a huge impact on all of us, it would be wise as a group to take steps to protect its effectiveness for the future.



> I think it is approaching 30 years of common use now with no signs of the development of resistance to OA


and most of those years were following the lable single broodless treatments a year mixed in with other treatments in rotation threw out the year. 

it changes when 20 OA treatments a year and no rotation becomes common


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## crofter (May 5, 2011)

_"We know from Maggi EtAl 2016 that one population of mites was 7X more resistant to OA then the other showing there was a genetic component that might be selected for." _

That would be quite phenomenal for sure. I tried to find the article but did not come up with it immediately. That has significance that would suggest this should be much more widely known unless it was simply an outlier and not repeatable. That was 4 years ago.


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## Cloverdale (Mar 26, 2012)

Cloverdale said:


> I learned the following in the second level of U of Montana Journeyman:
> 
> I asked if using OA vapor or dribble would compromise open brood, the response from the professor;
> 
> “In a study using two applications 14 days apart (which is becoming increasingly popular even though it is not an approved application method) there was a high percentage of young (12.6% and 9.5%) and old honey bee larvae (10.6% and 5.6%) killed after the first and second oxalic acid applications (percent death shown in parenthesis above). Also, the overall area of the open brood was reduced by 17.5% after the two applications and stayed low for about two months.”


OK, I asked on Bee-l and Randy O said the following the my question which was - Has there been any studies on oxalic acid sublimation and how it can affect open brood and adult honey bees that breathe in the sublimed oxalic acid?
Randy said:
I can't cite studies, but can offer personal observations.
We dribble around 3000 nucs each spring, and don't notice any adverse
effects of concern.
Re vaporization, it is most efficacious against varroa when there is no
sealed brood.
In colonies with brood that I've vaporized repeatedly, upon inspection I
didn't notice any problems with the brood.
Re bee inhalation of OA by adult bees, if there were substantial harm, we'd
likely see dying adults afterwards. We don't see that.
Bees have protective hairs in their thoracic intake spiracles to filter out
dust and as a barrier to tracheal mites. These hairs would likely also
filter out the tiny OA crystals that constitute the fog that you see. The
bees' setae (the feathery "hairs") that cover their bodies can, however, be
covered with crystals.

Someone also sent a personal email regarding research on dribble and sublimation on adult honey bees and varroa, which was good if anyone wants a copy. “ Effect of oxalic acid on the mite Varroa destructor and its host the honey bee Apis mellifera” Ivana Papežíková, Miroslava Palíková, Silvie Kremserová, Anna Zachová, Hana Peterová, Vladimír Babák & Stanislav Navrátil To cite this article: Ivana Papežíková, Miroslava Palíková, Silvie Kremserová, Anna Zachová, Hana Peterová, Vladimír Babák & Stanislav Navrátil (2017) Effect of oxalic acid on the mite Varroa destructor and its host the honey bee Apis mellifera, Journal of Apicultural Research, 56:4

Needless to say I am disappointed in that the instructor did not reply to my question. Being that this Entomology Dept. does research maybe that was their own findings.


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## Cloverdale (Mar 26, 2012)

msl said:


> The prof is referring to a dribble study HATJINA,HARISTOS 2005
> https://www.researchgate.net/public...stered_by_trickling_method_on_honey_bee_brood
> 
> Kevin O’Donnell's Individual Experimental Project for the UM master program found an 80+% drop in brood in 2/3s of the tested hives when they were given 3 weekly OAVs, but its a very small sample size and some queen loss that was unlikey OAV related, but mucks up the numbers
> ...


Yes that was the paper the quote was from. Thanks for sharin* that.


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## msl (Sep 6, 2016)

Here is a link for you frank 
https://www.researchgate.net/public...a_destructor_against_oxalic_acid_A_study_case


> These mor-tality percentages were between 2.8-fold and 7.2-fold higher for the „focal‟ mite population than for the con-trol mite population.


The study is often cited as "proof" of no resistance, when it shows its out there..
The group in question was an isolated apiary with little contact with other mites, it was treated a bunch, and the mites didn't evelove Resistance.
I suggest the sample size is way, way to small... if I took 50 hives and went TF with them and they all died I could say that bees will never evolve retiance to mites, but we know that's way to small of a sample to make that call. 
We know from the studys on coumaphos resistance that the US, The UK, and mainland EU all developed different resistance mechanisms... meaning that it more or less started with one mutation in one mite and spread to the borders. 

It could be the resistance only goes so far and will never be an issue, un like the 175X resistance we see in some synticks. 

coloverdale if you want to take 

Rewinding a bit, it could be the reduction in mite kill in the provap study was do to some OAV resistance in the mites, not break down or outher issue with the provap... It didn't have a pan heater control so its hard to say. 
If we go to Toufailia EtAL 2018 https://www.tandfonline.com/doi/abs/10.1080/00218839.2018.1454035?journalCode=tjar20
we see in the 2nd trial the while brood less the 1st OAV killed 98.3% of the mites, and the second treatment only 64.1% something is causing that resistance..

my worry is not how big the chance is(I don't think its huge), its the consequences IF it happens. 
The chances of me getting in a car wreck driving to get food tomorrow are very, very small, but you bet I will be wearing my seat belt do the consequences of not wearing it being so high... 
I am not saying stop the race, but it may be time to wave the caution flag and stop treating OAV as infaubul magic pixy dust, every other cem that was used (espicaly off lable) as a single silver bullet has failed, and yet beekeepers hop on to the next silver bullet. 

Its not the chance you will develop resistance in your apiary, its that some one, some were will and then its just a few mite bombs away from being coast to coast in a year or 2 if it get in to a large operation


as for brood mortality, it happens with many treatments... formic comes to mind
It would seem what ever it is with OAV and dribble its impacts are small enough to be ignored by most 
of note from the study you mentioned they found OAV the least effective method 

if you want to take a deep dive Rademacher, Harz 2006 give a good review of the avbaibul studys, sadly a bit dated https://hal.archives-ouvertes.fr/hal-00892183/document


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## crofter (May 5, 2011)

Too many leaps of faith, extrapolation, and isolated small sample size experiments for this to make a case for significant mortality from OA Vapor. Apparently some caution against repeated dribbles, though a small sample of people claim to have gotten away with it. 

Similarly I think the case for the surety that the mites will develop resistance to OA or Formic is not based on any physical indications from quality experiments. Those actually point the other direction. The case that resistance *has *developed to chemicals with totally different mechanisms and with other species, carries no logical weight in the specific instance.

I agree that as a general policy that rotation is a good thing to keep in mind.


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## Cloverdale (Mar 26, 2012)

A new study 2019:

Apidologie (2019) 50:363–368
* INRA, DIB and Springer-Verlag France SAS, part of Springer Nature, 2019 DOI: 10.1007/s13592-019-00650-7

A Scientific Note on the Effect of Oxalic acid on Honey Bee Larvae

Abstract: Abstract – The approval of oxalic acid as a treatment for Varroa destructor infestation of honey bee hives gives beekeepers an additional option for controlling this devastating parasite and disease vector, but the effects of oxalic acid on developing bees are not completely understood. In this study, we find that doses of oxalic acid not reported to be toxic to adult bees are toxic to larval bees. While it has been recommended that oxalic acid only be used during broodless periods because it does not penetrate cappings and is only effective in killing phoretic mites, it is tempting to use it at other times of the year because of the dearth of effective treatment options. Knowing whether oxalic acid is toxic to larvae and at what doses is important for beekeepers as they manage their colony population throughout the year.


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## johno (Dec 4, 2011)

Cloverdale your study does not include how the oxalic acid was applied and once again I believe they are refering to OAD, Msl there was also some study on treating colonies that I believe had been treated for years with oxalic where they were again treated and also hives that had never been treated with oxalic before were also given the same oxalic treatment so they could try to see if there was any difference in the efficacy between the 2 sets which might point to resistance being developed by the colonies that were heavily treated previousely with OA. The findings seem to indicate that the mites in the colonies that had recieved many treatment were more susceptable to the OA than the colonies that had never been treated before. I think Maggi was involvedwith this one.


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## Cloverdale (Mar 26, 2012)

johno said:


> Cloverdale your study does not include how the oxalic acid was applied and once again I believe they are refering to OAD, Msl there was also some study on treating colonies that I believe had been treated for years with oxalic where they were again treated and also hives that had never been treated with oxalic before were also given the same oxalic treatment so they could try to see if there was any difference in the efficacy between the 2 sets which might point to resistance being developed by the colonies that were heavily treated previousely with OA. The findings seem to indicate that the mites in the colonies that had recieved many treatment were more susceptable to the OA than the colonies that had never been treated before. I think Maggi was involvedwith this one.


Yikes wrong article! Sorry about that. I think I might still have your email from when I bought the vaporizer. I will send it you. I do want you to know that I use OAV all the time in my yard. What the heck would we do if we didnt have OA? I think even with a little brood mortality I would still use it.


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## msl (Sep 6, 2016)

> I think Maggi was involvedwith this one.


:thumbsup:
the link to it is in post #46 


> Cloverdale your study does not include how the oxalic acid was applied


directly fed to the larva 
at .01%, .05% and .1% the larva survied better then the controal








for some reason OA brood mortality seems more of a dust up between the OA camps than any real effect, and its realy only an issue if you go off label 
what kills brood? .... mites, formic etc 

Swinging back to JW's fly swatter comment, I want to go back to cloverdale's Papežíková, et al. 2017 study

Its sited in the EPA's 2018 technical report on OA 


> One study evaluated the action of different OAD treatments: by sublimation (1 g OAD per hive), oral
> 240 application (70 µg per bee) and topical application (70 µg per bee) to the abdomen of phoretic mites. The
> 241 concentrations approximate what would typically be used in a hive (Papežíková, et al. 2017). The study
> 242 found OAD crystals attached to the bodies of dead mites, even for those with brief exposure of five
> ...


We see its poison, not a fly swatter.. and there are (sposed)2 modes of action... contact and ingestion threw feeding on host bees, witch is why I am comfortable with a OAV/dribble rotation + the spit brood break as sufcant rotation... 
the ingestion is one we should watch... OA is water soluble, the mites feed on the fat body, glycerin is often used to make water soluble medications fat soluble. We have been seeing more and more on glycerin lately, it may be allowing better targeting of the mites


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## Juhani Lunden (Oct 3, 2013)

msl said:


> Here is a link for you frank
> https://www.researchgate.net/public...a_destructor_against_oxalic_acid_A_study_case
> 
> The study is often cited as "proof" of no resistance, when it shows its out there..


There was a quote (but not with the link from whereabout it was and whos) saying:
"These mor-tality percentages were between 2.8-fold and 7.2-fold *higher* for the „focal‟ mite population than for the con-trol mite population."

Quote from that study abstract: a „focal‟ population consisting of mites previously exposed to oxalic acid treatments, and (2) a „naïve‟ population that was never exposed to this acid, which allows setting a reference in the absence of historical data on our „focal‟ mites.

If there were resistance to OA, you would expect mortality of mites to be lower?


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## msl (Sep 6, 2016)

the study was sited, just no link easy google fu 
The point is it shows a genetic variation in resistance is all ready present, and like any trait if its heritable our management choices impact the selection and magnification..

the "focal" was an isolated yard with local stock, in a cold area that sees well below freezing day temps , the "naive" was out of a large commercial op in and area that never goes brood less with queens from a suply house...

they can call them "Naive" and say they have never been exposed.... but that's just silly, the mites there likely have more years of OA exposure in their genes then the "focal" pop..
IE I have never treated with coumaphos , but because of what was done by others I would bet $$ that I have coumaphos resistant mites.. thats kinda how things work, when bess and mites are trucked all over the country.


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## Juhani Lunden (Oct 3, 2013)

msl said:


> the study was sited, just no link easy google fu
> The point is it shows a genetic variation in resistance is all ready present, and like any trait if its heritable our management choices impact the selection and magnification..
> 
> the "focal" was an isolated yard with local stock, in a cold area that sees well below freezing day temps , the "naive" was out of a large commercial op in and area that never goes brood less with queens from a suply house...
> ...




But shouldn´t it read "non-mortality" or "surviving despite of OA" (of mites) instead of mortality?


I mean if mortality of mites is 2,8-7,2 fold in the population which was previously exposed to OA (focal), then I would expect that there has been no resistance build-up in this population.


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## crofter (May 5, 2011)

It seems to me that there is a trend to interpretation that suggests more than a little confirmation bias. Once a position has been taken it can narrow the perspective. 

Compared to some of the really nefarious habits of chemicals like coumaphos, fluvalenate, amitraz etc., Oxalic and Formic acids seem amazingly simple, straight forward and effective: they have their handling cautions but they are not sneaky about that. Not something parallel to a novel concoction like Thalidimide.

I cant quite understand what appears to me to be grasping for ways of digging up some dirt on them. Surely there are greater dragons to be slain.


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## msl (Sep 6, 2016)

> then I would expect that there has been no resistance build-up in this population.


Cant say as there is no pretest on the mites to determine thier base line , all the study shows us is one population was more resistant then another. If both were the same it would be no big deal, but what happened shows the mites have some how been selected for different levels of resistance. 

It could be very well given the "focal" location(cold winters) and management that the mites in both studys populations started at the same level, but those with more resistance to OA killed hives in the the harsh winters and died with them leaving only less resistant mites, an interesting twist on the "natural conditions leads to less vuriant mites" hypothesis ?

The flip side could be true as well, the mites in the so called "naive" population had brood year round and were in a situation were bombing out a hive would lead to dispersal via mite bombs any time of the year, that favors the grouth/spread of resistant mites

I find it odd the authors make no attempt to compare there results to outer studys on OA leathailty and that they used such an different protecall for what has been done in the past its hard to compare... I would have expected Maggi to use the same set up he used to find resistance and leathaity to synthetics, the standard way

MAGGI M., RUFFINENGO S., GENDE L., EGUARAS N., SARDELLA N., 2008.- LC50 baseline levels of amitraz, coumaphos, flu-valinate and flumethrin in populations of Varroa destructor from Buenos Aires Province, Argentina.- Journal of Apicul-tural Research, 47 (4): 292-295.

MAGGI M., RUFFINENGO S., DAMIANI N., SARDELLA N., EGUARAS M., 2009.- A first detection of Varroa destructor resistance to coumaphos in Argentina.- Experimental and Applied Acarology, 47 (4): 317-320. MAGGI M., RUFFINENGO S., NEGRI P., EGUARAS M., 2010.- Resistance phenomena to amitraz from populations of the ectoparasitic mite Varroa destructor of Argentina.- Parasi-tology Research, 107: 1189-1192.

MAGGI M., RUFFINENGO S., YAMANDÚ M., OJEDA P., RAMALLO G., FLORIS I., EGUARAS M., 2011.- Susceptibility of Varroa destructor (Acari: Varroidae) to synthetic acaricides in Uru-guay: Varroa mites‟ potential to develop acaricide resis-tance.- Parasitology Research, 108: 815-821.

but as soon as he gets involved with alumcap (SP) he changes how he is doing research
https://www.researchgate.net/public...s_mellifera_colonies_in_the_presence_of_brood
... funny how alot of names on that paper are on the patent for that product.




> Oxalic and Formic acids seem amazingly simple, straight forward and effective


and that's why we should be following the label, and suggesting people act in a manor that insures there effectiveness in the future, just encase there is a chance of resistance. 
the argument that "it been a long time and we still haven't" is a bit moot... we have had amtriaz in the states for 20 years, now its starting to waiver and resistant pockets are showing up 
You can't prove a negative, you cant prove resistance won't happen.. I am just suggesting we procide with optimistic caution and best management practices, not reckless abandon
the beekeeping industry has ruined just about every "wonder drug" it been given, mostly threw off label use and abuse... putting in cow ear tags, leaving strips in year round, not rotating treatments, etc 

I am suprized there is not more support for insuring the good stuff we have right now stays good. The "resistance can never happen" position is a short sited and ill informed one and not backed by our history.. It MAY be unlikely, but not impossibly.. Its not about digging up dirt, its about insuring that dragon doesn't have a chance to wake, even if the old wize man says it may never in our lifetime

if you told me 10 years ago the government would pay most people to stay home the month of 420 and home pot delivery would be deemed an "essential service" I would have thought (you were nuts) that would be highly unlikely... yet here we are.


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## Juhani Lunden (Oct 3, 2013)

msl said:


> those with more resistance to OA killed hives


Just to make sure:

are we talking about the death of mites or hives?

How can the mortality (of mites, I assume) be 2,8-7,2 fold, so huge difference?





(I starting to think there is something fundamental misunderstanding. Something I missed in what you are trying to say. I´m with you that I believe resistance to OA is possible. At least doses have gone up.)


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## msl (Sep 6, 2016)

> How can the mortality (of mites, I assume) be 2,8-7,2 fold, so huge difference?


Dose response... to be clear I miss qoated... it was 2.8-7.2 over control, witch was close, but not the same as the difrence between the 2 test groups From https://www.researchgate.net/public...a_destructor_against_oxalic_acid_A_study_case







We see that one group had almost no effect compared to control, and one population had more resistance. 



> are we talking about the death of mites or hives?


death of a hive over winter in a cold climate leads to the death of the mites, I was suggesting a posabul way the focal population may have been selected for the less OA resistance show in the study

Either way the studys conulstions are fairly standard and somthing I feel we should heed


> it is strongly recommended to rotate this acaricide with other miticides and with nonchemical control techniques applied in different seasons of the year, each one acting for a restricted period of time.


they suggest the short action time of OA is one reason we haven't seen reliance


> the fast degradation and the low residual of the OA make this product an in-teresting alternative acaricide. By this way, organic miticides exert lower selection pressure against Varroa populations compared to synthetic compounds. In Ar-gentina, the low selection pressures exerted by organic miticides is due to that this kinds of products is not used very often by beekeepers,


but this lack of pressure changes when we start more common use, and stacking treatment on top of treatment on top of treatment a few days a part, or start working with extended release systems like strips and shop towels.


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## johno (Dec 4, 2011)

Hey Msl, I get your message. Next year I can expect all my colonies to die as I have been using only OAV for mite control for the last 6 or 7 years, but never mind the good news is all the OAV resistant mites in my colonies will also die over winter.


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## Cloverdale (Mar 26, 2012)

johno said:


> Hey Msl, I get your message. Next year I can expect all my colonies to die as I have been using only OAV for mite control for the last 6 or 7 years, but never mind the good news is all the OAV resistant mites in my colonies will also die over winter.


Did you receive the email with the research paper?


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## crofter (May 5, 2011)

Well Msl I do think you are jousting at windmills. All the dire predictions could happen; many bad things could happen but we cannot be on guard against every possibility without losing our sanity. We have to attempt a reason appraisal of odds we are comfortable with and go with it. The amount of years and the nature of the killing mechanism with these acids with no sign of resistance (in any well credited test) makes that possibility very remote. I am comfortable with that assessment.

There is a possibility; some say a certainty that the tropilaeleps mite(sp.?) is on its way. That is probably a much stronger possibility than the risk of varroa becoming resistant to the physical damage of these organic acids. Much of what humans are doing today is very unwise. The problem we are facing to day is an example of removing geographic isolation of pestilence. 

Like I said, I think there are greater dragons to slay.


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## JWPalmer (May 1, 2017)

How does one argue that something is impossible with someone who is doing it? St. George has nothing on Don Quixote.


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## msl (Sep 6, 2016)

> That is probably a much stronger possibility than the risk of varroa becoming resistant to the physical damage of these organic acids.


Frank that's the problem, look at all the stuff I have sited in this thread alone... all of them put the mode of action as a poison, not a hammer
"resistance will not be an issue. It'd be like a ****roach becoming resistant to a hammer" Jennifer Berry once said.. The hammer is what stuck in peoples minds, and despite it not proving out under scientific scrutiny, every one remembers it and repeats it on the internet.. 

like wize Gerhard Brüning's work showing OAV get's absorbed in to the mites blood stream threw the foot pads and kills the mites via poison became twisted on the internet game of telephone in to "it burns there feet off, how can they develop Resistance to that"

https://oxavap.com/pictures/


snl said:


> From Gerhard Bruening..........
> Oxalic acid uptake:
> In the reports at hand, the effects of oxalic acid on varroa mites have been studied over a period of 12 years with simple methods. When feeding bees with honey syrup it was apparent that bees refrain from ingesting oxalic acid with the food and thereby that oxalic acid uptake by the varroa cannot happen via the bees system. When examining the feet (tarsus) of fallen-off but still alive mites under a microscope, major accumulations of oxalic acid crystals could be found at the outermost segment of the tarsus with the moist adhesive pad. The mites died within 24 hours of the examination. During this time it was noticeable that the oxalic acid crystals at the adhesive pad of the mites dissolved and penetrated the pad. This was accompanied by a simultaneous cease in life signs in the mites. This observation leads to the hypothesis that oxalic acid crystals are collected in great numbers with the adhesive pads on the mites feet, where they then dissolve within a few hours and penetrate the body of the varroa via the membranes in the adhesive pads. This hypothesis is also supported by the fact that the same observation can be made, regardless of the method of application (spraying, trickling or vaporizing).


you probably right that attempting to correct internet falsehoods that keep getting repeated is jousting at windmills (FMGO still keeps poping up).. but thought I would give it a shot so people can make(thier own) informed management decisions. 
Believing the mites are killed by "physical damage" from OA is not an informed position that is backed by the research. I find it interesting how much push back people are putting up to the truth, yet they have zero backing of facts or study's to support their end. 
Some times the OAV hardcores are a lot like the TF types and react quite negatively When you atemp to shine the light of science on their "understanding" of things.... 
As I have said before, chaff left unchallenged is one of the biggest problems for new beekeepers but hey at least I tried:digging: 

I wish I knew why (haveing fallen in to the TF trap in my early years) beekeeping generates passion and belief systems on the magnitude religion or politics, there an interesting case study here


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## clyderoad (Jun 10, 2012)

> I wish I knew why (haveing fallen in to the TF trap in my early years) beekeeping generates passion and belief systems on the magnitude religion or politics, there an interesting case study here


Only for some. 
Into one trap, out, then into another. In perpetuum.


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## crofter (May 5, 2011)

Msl;

I never said that development of resistance to the organic acids was impossible, but it certainly is not inevitable. My feeling is that you consider it far higher odds for it developing and build a case for it. The odds against or for either might be equal for all I know but extremely small risk is not something to spend inordinate effort to prevent.

I consider poison to be physical damage. I think that some of the truths you describe seem to be supported by rather obscure experiments. I dont see much in the way of independent repeatability of findings. Quite a bit of "could have been caused by; due to the small sample size etc." disclaimers. Undoubtedly I have not read as many of them as you have but that was not one of my hot buttons. I just have not seen enough evidence yet to lead me down that trail.

I would like to hear the story sometime about how you got led down the TF path. I take you generally for a pretty discerning and pragmatic person. 

I never was tugged in that direction. I have a great aversion to accepting anything that requires a leap of faith or where acceptance of analogies seem necessary to carry the story line.

If and when I start to hear credible claims that OA is starting to incur resistance I will get more religious about rotating it but I have an aversion to the synthesized organophosphates or whatever classification coumaphos, fluvalinate, Amitraz etc. belong. Perhaps its a case of "The familiar devil is the lesser evil!"


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## Juhani Lunden (Oct 3, 2013)

msl said:


> Dose response... to be clear I miss qoated... it was 2.8-7.2 over control, witch was close, but not the same as the difrence between the 2 test groups From https://www.researchgate.net/public...a_destructor_against_oxalic_acid_A_study_case
> View attachment 54497
> 
> We see that one group had almost no effect compared to control, and one population had more resistance.


Not until now I managed to get the study paper open. I missed the right button...


OK.
They used *very low* concentrations, and applied OA on mites in a Petri dish.


Now I understand.


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## Juhani Lunden (Oct 3, 2013)

One observation, no scientific value:

I get more and more phone calls from beekeepers interested in my resistant stock. And usually the story goes that mites have become a problem they no longer can handle. 

More treatments, and still more problems. Hives dying. Yards dying.

In Finland OA, formic acid and thymol are the most used treatments. Almost all Finnish beekeepers have been using them at least 20 years.


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## little_john (Aug 4, 2014)

> Frank that's the problem, look at all the stuff I have sited in this thread alone... all of them put the mode of action as a poison, not a hammer


That's an example of the 'single-variable thinking' I keep banging-on about.

The phrase which is invariably employed is: "... supports the hypothesis" - which is fine - but that is NOT the same as saying "NOT a hammer" - unless of course an individual has already decided (= pre-judice) that only one mode of action can possibly be responsible.



> "*Only *around 12 percent of mites displayed cuticular damage as observed under a dissecting microscope."


"Only" - why use such a word ? That's part of a single-variable sales-pitch.



> "These findings support the hypothesis that OA acts via contact toxicity on varroa mites *rather than* the OA crystals causing structural damage."


Again, such wording is attempting to sell the idea of a single mode of action. Why not multiple modes of action ? Is that such an unreasonable idea ?



> "The authors suggested that this could be due to metabolic disturbances and *changes in the bees’ hemolymph* affecting the survival of the mites, which are tightly adapted to their hosts."


Does such wording not put much of that report in doubt ?


Finely powdered sugar dislodges mites - I believe reasonably effectively, although I've never done this myself. How does it do that ? Is that mode of action analogous to that of the fine microcrystalline dust of Vapourised Oxalic Acid ?
I've yet to read a totally persuasive explanation of how Oxalic Acid kills mites. I'd really like to know that, but in the meanwhile I'm more than happy to use that substance in the same way as people over the centuries have used Jesuit's Bark as a remedy for malaria, without knowing exactly how it worked.
LJ


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## johno (Dec 4, 2011)

The latest research that I could not find is from Ramesh Sagili Phd from the University of Oregon. If you google that you will find his research.


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## msl (Sep 6, 2016)

I don't disagree with any of that LJ, it may still be an hammer, but the hammer hypothesis is lacking supporting data and we have a mountain of info to the contrary .. either way the point was we can't say "its a hammer and they will never be resistant to a hammer" as that's not an accurate statement or even a reasonable informed one, and can lead people to poor management dissistions when it keeps getting repeated. 
All of the wording you are taking issue with comes from the US EPA report, not the studys. For me it dosn't put the studys in doubt... the only thing the rebuts science is better science. 
I often talk about following the trend, not just one study.. the trend is its not a hammer. Now if some studys pop up showing it is hammer, burns there face and legs off, gets between the shells joints like DE etc then that bring in the doubt, if any one has anything like that, please send it to me

side note I have often wondered if OAV "dusting" as happens when you vape a hive causes grooming like sugar dusting 

Frank I am not saying resistance is inevitable, just that we don't know enuf to say "it can never happen" as is often repeated, I am trying to stop the parroting of bad info, the same as many would do if some one started talking FGMO, same as I did when people started talking OA fogger cures



> If and when I start to hear credible claims that OA is starting to incur resistance I will get more religious about rotating it but I have an aversion to the synthesized organophosphates


by then, its too late. It doesn't matter what you do as a small beekeeper, it matters what the industry does. 
to that point Sammataro EtAl 2005 https://www.researchgate.net/public...ae_to_acaricides_and_the_presence_of_esterase



> . Results of a survey of mites from the Carl Hayden AZ lab and from cooperators in five locations (Arizona, California, Florida, Maine, North Dakota) showed that some mites were susceptible to all three acaricides (Amitraz, Coumaphos, Fluvalinate) in the spring of 2003, but by fall most mites were resistant. *Mites were resistant to all chemicals, even from beekeepers that do not treat colonies with acaricides*


emphasis is mine, even the TF people ended up with resistant mites! Its a landscape scale thing, not a keeper by keeper thing

for the most part once there is a resistance problem, we don't get the chemical back, the trait becomes fixed in the mite population do to lack of out breeding. unless of corce there is a mal adaptation to survival in the absence of that cemicals use, but that's not what we are seeing(IE resistant mite in TF hives), we are not seeing cems mites became resistant to regain there historic effectiveness.. we have not seen a chemical the mites are becoming resistant to be "saved" by rotation after the warning flags go up... we just move too many bees (mites) form place to place.

IE https://journals.plos.org/plosone/article?id=10.1371/journal.pone.0227264
We are starting to see pockets of amitraz failure, is there a lot of chatter about it? are beekeepers taking action and changing their ways?



> The latest research that I could not find is from Ramesh Sagili


perhaps this?
https://tvbabees.org/resources/Documents/TVBA_Sagili_Feb25_2020.pdf
there is a bit more detial here on page 22
https://westernapiculturalsociety.org/wp-content/uploads/2020/01/02_2020_was_journal-reduced.pdf

it a good find,( 1st time I have seen it suggested that sugar shake is better the a wash) its the type of study I had been talking about, tracking the brood on clear sheets etc
I look forward to published results, but till then lets look in to what the graphs show using a square and going by the 1 week mark

OAV hives had 14% less eggs, 7.7% less young larva and 4.5% less old larva then the control that's from a SINGLE OAV treatment

the OAV hives started at 1.8% mites, 3 weeks post treatment they were at 3.2% a 77% growth... more then the untreated control hives !!!
the formic went form 1.6 to .3% a 81% reduction in the mites

so OAV likly kills brood, (despite what the internet says) and we have always know formic was ruff on brood.
I would supect more OAV treatments will lead to more brood loss and you would see the 2nd/3rd treatments to kill even more as the extra dose is talking sub lethal exposure to lethal with the extra exposure..

so from a management perspective I would love to see a multi dose trial to see what level of brood mortality we get when enough OAV doses to control the mites and how that mortality compares to formic... with those numbers people can make informed mangmnet distions 

good stuff

johno, in your experance how many treatments do you fell it would take for OAV hives in this set up to match the mite conroal of the formic?


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## crofter (May 5, 2011)

Msl; look up the cost of maintaining a resistance. Unless it continues to be a benefit to an organism it usually fades, does it not. Amitraz resistance developed over some ill advised practice but returned to being highly useful though I hear that is again fading in some areas. There is suspicion that the same cattle mite formulations might be party to that as it was with the original period of ineffectiveness. Resistance is not a once and for always thing in most cases. To say that this would be the case if some resistance to OA started to appear, I think is a bit fear mongering. Very remotely possible but not highly likely. 

I think you are too bought into discrediting OA to have unquestionable objectivity. I dont see it in other areas of your bee keeping; I always read your posts with interest. Why the missionary zeal in this particular subject


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## johno (Dec 4, 2011)

Msl I take it you did not find the resent research by Ramesh Sagili Phd University of Oregon regarding brood damage by OAV. I left formic to go to oxalic because of the inconsistant results from Formic, still got about 4 gallons of formic if you would like some. Look when you treat and kill only phoretic mites in a week after your treatment your count could be higher than when you started as maybe 60% of the mites were in brood and have since emerged therefore treat on Mondays and Fridays till they be no mo as they might say in de South. So all in all my colonies will recieve at least 12 treatments a year and when I take my honey in Late June early July many of those colonies I cannot get down to 3 medium boxes so must be doing something wrong.


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## msl (Sep 6, 2016)

> Msl; look up the cost of maintaining a resistance. Unless it continues to be a benefit to an organism it usually fades


understand were your coming form, be we don't see that in mites at this point, if we did the magic bullets that realy kicked the snot out of them in the old days would just be rotated back in and we wouldn't be talking about resistance at all 
anyone guess... maby the resistance isn't costly or dosen't provide a reproductive disadvantageous set up... my "gut" is its likely do to the brother sister mating setup. 



> I think you are too bought into discrediting OA to have unquestionable objectivity.


Well no one has objectivity, and if you think you do, your fooling you self, best I can do is say to bring me a group studys that counters my group of studys

your taking it all wrong, as Noted earlier OA is my sole chemical treatment, I have a vested interest in protecting it 

Spring split, drone culling, 1x Aug dribble, 2x winter broodless OAVs.. I am comfortable that OAV/dribble have different enough actions that mixed with the other methods I am getting enough rotation.. (or its what I wan't to beleave and my bias is on high) per year one generation of mites is exposed to dribble, one to OAV

No were am I slamming OA, I am just pointing out its not magic pixie dust and has its limitations. 



> I dont see it in other areas of your bee keeping;


I think you do, and we are just on the same side of the debate then, so it gets wiped by your bias... Ie I think go after the "natural selection" fokes with the same sprit and data dump.. they have the same problem as here... some one said something on the internet that they locked on to that is often not supported by the data and then it keeps getting repeated reinforcing peoples position 

Anyway, I have an open mind, send me a study that contradicts the studys I used(I have listed many) to form my opinion on the subject , then we can debate the validity of each study's findings. I think its uselessness to debate opinions unless we have the information on hand that was used to form them as every one has an opinion, especially on line... 
Its those who have an informed opinion that are worth while to debate.... and thats one of the reasons I keep up a sprited dialog with the likes of JohnO and GregV.. If I poke them enuff they often will come up with some gem and teach me something (such as Johno's finding of Ramesh Sagili 's work) and I hope I do the same for them



> Msl I take it you did not find the resent research by Ramesh Sagili Phd University of Oregon regarding brood damage by OAV.


link is in post #70


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## crofter (May 5, 2011)

"_nderstand were your coming form, be we don't see that in mites at this point, if we did the magic bullets that realy kicked the snot out of them in the old days would just be rotated back in and we wouldn't be talking about resistance at all
anyone guess... maby the resistance isn't costly or dosen't provide a reproductive disadvantageous set up... my "gut" is its likely do to the brother sister mating setup_" 

Did you read the example of the amitras losing effectiveness and then recovering after people left it alone for a while and restarted some seasons later using the labeled Apivar. I think the same has happened with coumaphos and fluvalenate. They still knock the snot out of mites but contamination issues suck! I see no particular reason to think that any incipient resistance to OA would not follow a similar pattern as I alluded to in an earlier post. That is IF resistance did develop. After thirty years it seems remote.

"No were am I slamming OA, I am just pointing out its not magic pixie dust and has its limitations".

Yes it has limitations; I think a manner of presenting it with time release similar to what is done with the Apivar, MAQs, Apilife Var, etc. could have promise. Peak exposure levels are reduced and may get approval for use with supers on. It has such approval on other continents. I am working on that. Waiting to get some mite counts on a few hives exposed that way since last season. Quite a bit of development with that on the New Zealand forum.

"_I think you do, and we are just on the same side of the debate then, so it gets wiped by your bias_." Seems like rather convoluted reasoning but anyways it is good to know that we agree on some things.


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## msl (Sep 6, 2016)

> I think the same has happened with coumaphos and fluvalenate


Fluvalenate some what, coumaphos not so much The reversion can last just a few treatments and then the area is full of resistant mites again - Canadian Honey Council (2008). Request for Emergency Registration - Apivar Pest Control StripTM for Control of Apistan – CheckMite –Resistant Varroa Mites (Varroa destructor) on Honey Bees (Apis mellifera) in CANADA - 2008 

we see in your country just how rapidly resistant mites spread, and I do mean spread, not develop... it could take decades and decades for a mutation to pop up that gives mites a survival advantage over a chemical... but when that happens, and that chemicals use is wide spread the resistant mites spread about as fast as they did with there initial invasion

"The spread of resistance is proven to be rapid. The VAR mites resistant to fluvalinate was first reported in Canada in 2001, and by 2002 it was already spread in most of the province (CAPA, 2003; Canadian Honey Council, 2010). 
Similarly when coumaphos resistance was first discovered in 2003, by 2006 it was reported in many provinces (CAPA, 2004; CAPA, 2007; Canadian Honey Council, 2010)." 
https://www.ontariobee.com/sites/on... V13 Honeybeepackages from USA_Oct21_2013.pdf 

this why I am suggesting the time for (the industry as a whole) rotation is well before resistance is reported


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## Birdee (Oct 3, 2016)

That is very interesting. I used the OA vap early last spring and Formic Pro this year for mites. Both seem to work well for me. Did you find the beekeeping program with the University of Montana helpful? I have been looking and liked that one due to the complete online format.


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