# Strain of B.T. toxic to Varroa isolated



## Harley Craig (Sep 18, 2012)

got a link to the article?


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## clyderoad (Jun 10, 2012)

Thank you JWChesnut.
Something many of us have been quietly hoping for.
It would be terrific if this works and becomes available. All of our hats will be
off to the academic research community who gets a bad rap alot of times.
You're right- way cool.


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## bevy's honeybees (Apr 21, 2011)

Is this the same BT that is used for preventing wax moths?


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## Kamon A. Reynolds (Apr 15, 2012)

It would be fantastic for beekeepers big and small if a controllable, reliable product based on this could be made.


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## JRG13 (May 11, 2012)

Probably a different sub-species.


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## FlowerPlanter (Aug 3, 2011)

That does sound promising, maybe Varroa will end up on the endangered species list.

I wonder if Monsanto will make BT Bees.


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## beeware10 (Jul 25, 2010)

hopefully it will work and be available at a reasonable price. every university in the us has been working on varroa and the break thru may have been found by a Mexican researcher ?


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## Harley Craig (Sep 18, 2012)

So apparently this has been know for awhile? from 2005....or is this something different? http://www.beesource.com/forums/archive/index.php/t-200331.html


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## JWChesnut (Jul 31, 2013)

bevy's honeybees said:


> Is this the same BT that is used for preventing wax moths?


No. B.T. is a broad bacteria -- there are many bacterial strains that are highly specific to particular insects due to variations in the gene encoded toxin. BT works by germinating in an insect' s midgut, are releasing a large molecule that binds with specific sites on the host's gut wall cells. The binding forms pores in the gut cells which leak their contents into the gut. The ulceration quickly kills the target insect.

The binding site protein is matched to particular insects (or families), leading to high host specificity.

I can find little information on BT affecting mites (which are not insects). Most sources document the relative potentation of red spider mites when other pests are decimated by GMO BT Cotton and similar case studies.

Some good information on the mode of action in these pages:

http://archive.bio.ed.ac.uk/jdeacon/microbes/bt.htm
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC1857359/
http://www.hindawi.com/journals/isrn/2014/135675/


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## Bob J (Feb 25, 2013)

This would be an awesome development! Man I hate mites! :thumbsup:


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## jfmcree (Mar 10, 2014)

We probably need to know a bit more about how the BT was applied. The mites we are really going after are the ones sealed inside the brood. BT for wax moths can persist for some time in the wax killing off the moth larvae. It would be a wonderful thing if the same approach killed the mites. It would be less wonderful if the mites had to be bathed in a BT spray.

Has anyone bought the article to learn more?

thanks, Jim.


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## Tenbears (May 15, 2012)

A prerequisite of bathing Mites in BT would be highly unlikely. The nature of Bacillus Thuringensis is that it is a long lived Bacterial spore that tends to be host specific. That is why it has become such a innovative way of pest control. it equates to setting a trap for the targeted host and waiting for it to arrive.


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## Tenbears (May 15, 2012)

clyderoad said:


> Thank you JWChesnut.
> Something many of us have been quietly hoping for.
> It would be terrific if this works and becomes available. All of our hats will be
> off to the academic research community who gets a bad rap alot of times.
> You're right- way cool.


Who has been quietly hoping? Most I know have been hoping quite loudly for such a discovery. :banana:


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## Oldtimer (Jul 4, 2010)

JWChesnut said:


> BT works by germinating in an insect' s midgut, are releasing a large molecule that binds with specific sites on the host's gut wall cells. The binding forms pores in the gut cells which leak their contents into the gut. The ulceration quickly kills the target insect.


Excellent. Kind of like AFB for varroa mites!


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## SoylentYellow (Dec 10, 2013)

Every other sub species of BT had to be ingested by the target insect to work.
I wonder how you deliver the BT into a blood sucking mite?
Also didn't think that BT was a spore former.


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## dsegrest (May 15, 2014)

SoylentYellow said:


> Every other sub species of BT had to be ingested by the target insect to work.
> I wonder how you deliver the BT into a blood sucking mite?
> Also didn't think that BT was a spore former.


I was thinking the same thing. Also BT normally works on the larval stage.


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## BernhardHeuvel (Mar 13, 2013)

Delivery through the feet of the mite. They have sticky pads on the end of their legs and those have to be moistened all the time to let the mites stick to the bee. So there is an open channel from the sticky pad right into the inside of the varroa mite. Basicly, if the mites walks over something it'll load whatever it walks on. Like powder sugar, oxalic acids...or bacteria proteins.

Because the bees' hair are electrically loaded, they tend to draw small particles (pollen, dust,...) to it. 

So I reckon' all you need is a powder blower or a shaker, to distribute the proteins to the mites.


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## GaryG74 (Apr 9, 2014)

Sounds very promising. Thank you for the post JW.


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## Michael Bush (Aug 2, 2002)

Now if they find a Bt strain to kill SHB...


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## jimsteelejr (Sep 21, 2012)

It sounds like a great idea. But--with less than a 100% kill rate that means there are survivors. Are they survivors because they did not contact the B.t. or did they survive the exposure? If they survived the exposure how long before the varroa survivors repopulate with resistant stock. Evolution is a seesaw battle between host and pest. I feel our best hope is still breeding bees that survive the onslaught of varroa. While we apply no chemical treatments to our hives we are not treatment free. We use brood breaks, splitting and drone frame trapping. All of our bees are from swarm capture and cutouts. While some are just escaped managed bees some are from hives that have been feral for several years. Our hope is that some of them are going to be the varroa resistant bee that we have been looking for. I don.t think we can make any claims until a hive has gone thru two winters and survived. We have been very bad at keeping records until this year so we will see.


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## Oldtimer (Jul 4, 2010)

It's a great theory and we are all hoping it will work. But realise the same evolutionary theory applies to both.

If it turns out mites can evolve resistance to BT, then by the same principle they can evolve resistance to varroa resistant bees. The battle is that see saw thing you mentioned, and is the reason bees are not winning the battle to become treatment free. A factor in the mites favour is that in the time span it takes bees to produce a new generation, which genetically for bees is one queen to the next queen, in that time, mites have had many generations and a lot more mites. Giving them in theory, an evolutionary advantage.

Thus, even Primorsky bees that have been exposed for a long time are only able to survive as a species more so than individual colonies whose life span will often be cut off early.


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## lharder (Mar 21, 2015)

But if you follow that logic to the extreme, multicellular life would never have had a chance to evolve before getting squashed by rapidly evolving viruses and bacterial. Obviously more is going on. Yes there are arms races, but its not a desperate fight to avoid extinction. Its almost rather a case of intraspecific competition playing out against another intraspecific competition resulting in mutual change of form/function. But the overall dynamic remains about the same. In fact many predaceous critters evolve self limiting mechanisms like territorialism. The goal is not to limit a species to x density, rather eliminate the competition. The kinds of problems associated a new infestation of something like varroa like are usually episodic. We see these mass die offs in nature followed by wringing of hands, followed by recovery without much understanding what actually happened (there are exceptions or slow recoveries). There is a good chance that by treating and moving stuff around, beekeepers have been interfering with the ecological and evolutionary adjustments necessary to regain some stability. Hence the recovery is slower than it should have been.


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## Oldtimer (Jul 4, 2010)

Agree mostly. There was an excellent example in my country a few years ago, that I hope will parallel with bees. We have a native plant that mostly grows wild but is also is a popular garden plant, known as the cabbage tree. Around 30 years ago they started dying. Nobody could figure it out and across the country was the ugly sight of dead and dying cabbage trees. There was the worry they would go totally extinct. 
Eventually the culprit was found, a tiny beetle that was accidentally introduced from Australia. They were feeding on cabbage trees and in the process spreading a cabbage tree virus that already existed but did almost no harm. But now with it being actively spread the trees were dying. This continued for maybe 10 or 15 years but a few trees lingered on. Then less dead trees were being seen and now population is back where it used to be. See the correlation with varroa? So there can be success stories. With the cabbage trees no human intervention was made to do anything about it.



lharder said:


> but its not a desperate fight to avoid extinction.


Yes it is. The huge majority of species that have ever existed on earth, are now extinct. 
And this is the flaw with TF philosophy. It is confidently asserted that "evolutionary theory" states that organisms confronted by a threat will evolve defences and survive. This statement is what we want to hear, but ignores the reality of history, which is that most times when a species is confronted by a new predator, such as what happened when North and South America joined, many species go extinct rather than evolve defences. In fact most species have ended up extinct.

However it does appear that at least some bees are evolving enough defences to survive wild so there is hope. But seeing as _A. cerana_ have lived with mites so long but have not conquered them and are not very productive bees, we cannot automatically assume that _A. melifera_ will be able to and still be in the form we want. Since average TF losses were almost 50% last year the journey is clearly not over.


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## Phoebee (Jan 29, 2014)

Oldtimer, the operative saying that applies here is attributed to the famous German philosopher, Nietzsche, who said:

"What does not kill me makes me stronger."

Most people who quote this don't know how Nietzsche died. Sometimes it _*does*_ kill you. Sometimes _*horribly*_.


https://en.wikipedia.org/wiki/Friedrich_Nietzsche


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## Harley Craig (Sep 18, 2012)

I still don't understand how this is new if they were talking about it 10 yrs ago, if it worked you would think everyone and their sister would know about it and use it


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## jimsteelejr (Sep 21, 2012)

Oldtimer said:


> It's a great theory and we are all hoping it will work. But realise the same evolutionary theory applies to both.
> 
> If it turns out mites can evolve resistance to BT, then by the same principle they can evolve resistance to varroa resistant bees. The battle is that see saw thing you mentioned, and is the reason bees are not winning the battle to become treatment free. A factor in the mites favour is that in the time span it takes bees to produce a new generation, which genetically for bees is one queen to the next queen, in that time, mites have had many generations and a lot more mites. Giving them in theory, an evolutionary advantage.
> 
> Thus, even Primorsky bees that have been exposed for a long time are only able to survive as a species more so than individual colonies whose life span will often be cut off early.


While mites reproduce every few weeks they do not produce much genetic diversity since mating is frequently brother sister. Bees on the other hand may only reproduce (swarm) once or twice a year but the queen mates with multiple drones-12 to 15 is often quoted. So each hive has a lot of genetic diversity built in. This allows the bees to evolve quickly. I think the bees are winning there are a lot more feral bees than there were a few years ago and a lot more treatment free beekeepers. I hope this B. t. product gets on the market because it may help reduce the number of chemical treaters out there. With a lot of B.t. in use it may become established in the feral bees and offer one more natural weapon for the bees. The goal is not to eliminate varroa. I don't think that is possible given the wide distribution. The goal is to reach a balance with varroa and its viruses so that it just becomes a background stressor. With B.t. in the feral population it may evolve along with the varroa and maintain some toxicity to the mite.


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## Phoebee (Jan 29, 2014)

Please understand, evolution is not likely to make Varroa mites extinct. Given time, it should make them less deadly. There are two routes to this. First, if the goal of mites is to make more mites, killing their hosts makes this problematic. They can only get away with it in artificial situations where people keep providing them with more bees with colonies in close proximity. In nature, as they diminished the bee population they would become isolated, and then when they killed off the colony they were in they would die out. The survival of the fittest mite, in a natural situation, requires that they leave the bees alive and producing brood, and the would thrive best if the bees remained fairly healthy.

The low-hanging fruit for Varroa is to not carry such harmful pathogens. The most rapidly-reproducing organisms in this whole problem are the _*diseases*_ carried by Varroa. 

This, it turns out, is the natural course of the evolution of diseases. Disease organisms gradually become benign commensals (organisms getting along with their hosts with no harm), and may eventually become symbiotes (where benefit between host and organism is mutually beneficial).

The other fond hope is to breed better bees. Some combination of these trends is the likely eventual outcome. We'll forget Varroa at some point and worry about something else.


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## JWChesnut (Jul 31, 2013)

Phoebee said:


> This, it turns out, is the natural course of the evolution of diseases. Disease organisms gradually become benign commensals (organisms getting along with their hosts with no harm), and may eventually become symbiotes (where benefit between host and organism is mutually beneficial).


I object strenuously to this postulate presented without any citation. I refer to this as the "peaceable kingdom" or "Panglossian Darwinism" theorem, "Evolution is for the "Best" in the Best of all possible worlds." 

The idea that Evolution is directed towards perfection is ubiquitous -- the classic image of the Ascent of Man is defining. In the rubble of a post-nuclear holocaust, perhaps the alien scientists studying the evolution and extinction of the genus **** will conclude that the evolution of the brain did not contribute to fitness at all, but instead was a hypertrophy of a lethal mutation.

A fundamental paper in disease severity is Paul W. Ewald. HOST-PARASITE RELATIONS, VECTORS, AND THE EVOLUTION OF DISEASE SEVERITY, 1983 Ann. Rev. Ecol. Syst. 1983. 14:465-85. Ewald's paper was an opening shot against the idea that disease will always "get better". Since his courageous rebuttal, the evidence has accumulated, Disease can occupy many evolutionary equilibriums -- some of those are terrifyingly fatal. A common thread -- horizontal disease transmission (i.e. Robbing out of diseased hives) promotes virulence.


The paper (available from JSTOR for online reading) concludes,







((presented as an image because the text behind the pdf is garbled)).









Cite: http://www.jstor.org/stable/2096982

A really useful paper to broaden the discussion beyond evolutionary bromides is:
EVOLUTIONARY ECOLOGY OF PLANT DISEASES IN
NATURAL ECOSYSTEMS
Gregory S. Gilbert
Free pdf at: http://169.229.201.201/garbelotto/downloads/GilbertAnnRev.pdf


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## lharder (Mar 21, 2015)

Yes it is. The huge majority of species that have ever existed on earth, are now extinct. 

Are you sure its disease/parasites/predators that cause extinction or are there other factors? I don't discount them but the story often begins with a climate shift/disaster with something anything committing the coup de grace. The basic ideas behind it are outlined by Wilson and MacArthur looking at extinction on islands. The smaller the habitat, the more at risk a species was for extinction due to various factors. At least in recent history most extinctions probably are do to introduction of new competitors, members of the same guild, rather than outright predation. For example I don't think we have many native species of earthworms in North America, being almost entire replaced by European ones. Some western species of bumblebees are now in serious decline with introduction of Eastern species used in greenhouse pollination. Lots of our parasitoids are being replaced by foreign species, and its difficult to find our native species of mantid, but the Asian one is all over the place. 

Yes some species can be killed off by predators/disease, but I don't think the honeybee was ever in any danger with varroa. The range of the honeybee was too expansive, the types of habitats diverse, the honey bee is a generalist, the african sub type quickly adapted and there is gene flow between the two. The solutions to varroa resistance are relatively simple mostly involving behaviour. The tools are in the tool box, they just need to be used. And we have tf success with actual beekeepers (beekeepers in my mind are hopeless incompetent), in a sea of maladapted genetics where selection is thwarted by treatment. No wonder success is only 50%. Pretty good since most of us are useless beginners at the beginning of the selection process. 

But I grant you, the jury is a bit out yet. We do have cases where adaption is painfully slow. Some of our introduced fungal diseases of trees for instance. White pine blister rust was introduced around 1900. A few scattered stands of pines barely make it to being able to produce seeds before being wiped out. And of course Dutch Elm disease. Also Chestnut blight. All introduced to North America relatively early in the 20th century. That ****ed problem with moving too much biological material around crops up over and over, and will probably slow adaptation of honeybees to varroa.


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## lharder (Mar 21, 2015)

JWChesnut said:


> I object strenuously to this postulate presented without any citation. I refer to this as the "peaceable kingdom" or "Panglossian Darwinism" theorem, "Evolution is for the "Best" in the Best of all possible worlds."
> 
> The idea that Evolution is directed towards perfection is ubiquitous -- the classic image of the Ascent of Man is defining. In the rubble of a post-nuclear holocaust, perhaps the alien scientists studying the evolution and extinction of the genus **** will conclude that the evolution of the brain did not contribute to fitness at all, but instead was a hypertrophy of a lethal mutation.
> 
> ...


And yet when we survey disease virulence, extreme virulence is not often the norm. I mentioned some tree disease. Where they come from, native species of the same genus are just fine with vectors around that promote transmission. That said I like the theory, only there is more going on. Ectomycorrhiza are an excellent example of the complexity. Some of thought to be parasitic, others benign, some are symbionts, sometimes they can switch roles depending on context. They are probably in active competition, and have a role in suppressing root disease transmission of some nasties by a variety of means. They have basically an unlimited root network to move along, and can propagate by spores. An environment designed for virulence.


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## Phoebee (Jan 29, 2014)

I believe the earthworm thing is that at least in the north, earthworms didn't survive the ice age. Glaciers stripping the land bare will do that. 

They survived in southern climates but the rate of migration is about 9 meters a year, so in 14000 years they could only have migrated about 126 km on their own. Thus, Europeans bringing over plants in earth introduced earthworms, and more importantly spread them wherever they moved. So in the glacially-cleared areas there would have been no earthworms for more tens of thousands of years without human intervention, by which time another ice age might strip the land again.

Sorry ... no citation of papers here. I know JW wants us all to post only fully peer-reviewed papers here, with verified citations. My budget does not allow me to download the paper he did the screen-grabs of ($35), and life is too short to jump thru the hoops required to take a peek online. I must rely on the 1975 Biology degree, admittedly from the dark ages before that 1983 paper. But I do try to keep up and I don't think there has been a widespread acceptance of what he says is the finding.

Introduced diseases can render a species extinct. Dutch Elm disease almost killed off American elms. Last I heard, two trees survived, apparently resistant. One of them has been the source of an attempt to repopulate the species. Without human bungling, the disease probably would not have been introduced. However, without human help, the re-population would probably be hopeless, and total extinction would have occurred. Compare this to a dogwood blight a couple of decades back. You barely hear about it these days, but at the time people were worried that we would lose them. And then there are the tracheal mites. Anybody still have a problem with them?

I can point to numerous examples of diseases that have lost virulence over time. Bubonic plague is a case in point. And having studied symbiosis, I can tell you that we would not be here if some primitive cell had not become host to the bacteria that we now call mitochondria. The _very_ long view is for disease to become less virulent (which is not to say it does not remain a disease). Killing the host is a bad tactic for continued survival, and it has a high probability of causing the extinction of the disease.


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## JWChesnut (Jul 31, 2013)

All organisms die. The lineage survives when the rate of reproduction exceeds the death rate. Death from Varroa is infrequent in the first year, and hives can be managed to swarm and reproduce in the second spring --- as LHarder in his year-and-a-half beginner experience can attest.

_Apis cerana_ swarms six to eight times per year. Apis mellifera swarms every other year. 
A population of Apis cerana naively encountering and in direct niche competition with A. mellifera would select for the most virulent Varroa. A. Cerana has a strong adaptive advantage via selecting a lethal strain of Varroa. It's lineage survives and it competitor is suppressed.

The subspecies of Africanized Honey Bees (strongly in-breeding) encounters a niche competitor in the American south-west. The situation is parallel to the Vladivostok encounter: AHB will select for maximum virulence, as that strain has adopted to migrate and swarm frequently; whereas the European lineage has those traits suppressed. Relative, rather than absolute, advantage is key to understanding evolutionary dynamics.

I predict an evolutionary equilibrium for Varroa that causes queen supersedure in the second spring with uncontrolled swarming and mother colony death. That is incompatible with thrifty and economic beekeeping.


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## lharder (Mar 21, 2015)

JWChesnut said:


> Having started beekeeping in the early 1970's; I don't believe I am a "useless beginner". Having populated an experimental TF apiary in 2002, I don't believe I am inexperienced in that mode. I advocate for experimentation, not blind assertion.
> 
> A massive problem in hobby beekeeping circles is the promotion of untested beliefs by self-appointed experts.
> For instance, read this message by a poster on a TF forum:
> ...


Hmm, 45 years with keeping bees compared to how many millions of years of evolution acting on bees? Plus the fact beekeepers in general been pretty dopey about moving stuff around. Make the same mistake over and over and yes you can call into question the competence of the system. There is a basic operational flaw. So we should take tested failure over tf methods? I don't see the sense in that. But that is besides the point of this discussion anyway.


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## lharder (Mar 21, 2015)

Phoebee said:


> I believe the earthworm thing is that at least in the north, earthworms didn't survive the ice age. Glaciers stripping the land bare will do that.
> 
> They survived in southern climates but the rate of migration is about 9 meters a year, so in 14000 years they could only have migrated about 126 km on their own. Thus, Europeans bringing over plants in earth introduced earthworms, and more importantly spread them wherever they moved. So in the glacially-cleared areas there would have been no earthworms for more tens of thousands of years without human intervention, by which time another ice age might strip the land again.
> 
> ...


Your post prompted me to do a bit of digging. Here is an interview that gives an overview and more digging can be done to get at published sources. http://www.npr.org/templates/story/story.php?storyId=9105956

So its more complicated than my old half remembered information and your newer one. He stated in the interview that even in the south natives have been greatly impacted by invasives. The story of earthworms in northern parts re glaciation and preglaciation probably is a bit of mystery. I can believe the basic idea of slow migration, but can imagine other ways to speed up the process. Birds making nests with mud for instance and debri movement on north moving rivers. Thanks for posting and updating me. 

As for the trees, its not yet an extinction event. The remnants are hanging on. The basic problem in some of these cases is alternative hosts that keep the pathogen hanging around. No escaping it. Tree turnover is slow, we have to wait a long time to test the idea.


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## Judy Bee (Jul 4, 2006)

The article was published last year - Nov. 2014. I wonder why we haven't heard more about it. If the entire paper shows materials and methods someone surely is trying to repeat the experiment. (I'm impatient)


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## Harley Craig (Sep 18, 2012)

Judy Bee said:


> The article was published last year - Nov. 2014. I wonder why we haven't heard more about it. If the entire paper shows materials and methods someone surely is trying to repeat the experiment. (I'm impatient)


 like I said earlier in this tread it was discussed 10 yrs ago, if this theory held water, I'd imagine everyone and their sister would be using it and varroa would have already been a thing of the past.


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