[msl]

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?

 

[msl]

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

 

[msl]

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

 

[msl]

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

 

[msl]

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

 

[msl]

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.

 

[msl]

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

 

[msl]

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

 

[msl]

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
243 minutes. Only around 12 percent of mites displayed cuticular damage as observed under a dissecting
244 microscope. Besides two fatally damaged mites—which had missing legs and a split dorsal shield—the
245 majority that sustained cuticular damage had only mild compression of the dorsal shield, which would not
246 be expected to affect viability. These findings support the hypothesis that OA acts via contact toxicity on
247 varroa mites rather than the OA crystals causing structural damage. The authors speculated that OA may
248 affect the mite’s ability to hold onto the bee’s body and/or its ability to re-infest the host. The group found
249 that oral treatment of bees with OA also caused mite mortality, despite there being no direct contact of the
250 mites with OAD crystals. The authors suggested that this could be due to metabolic disturbances and
251 changes in the bees’ hemolymph affecting the survival of the mites, which are tightly adapted to their hosts.

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

 

[msl]

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.

 

[msl]

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.

 

[msl]

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.

 

[msl]

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/

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

 

[msl]

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?

 

[msl]

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

 

[msl]

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