# OAV as a monitoring tool and not just a treatment



## Arnie (Jan 30, 2014)

I've done it. It works. However, I mentioned it here and the idea was not well received. Get ready.

The thing I found is to keep monitoring the drop every time you treat and every week or so when not treating. Then you get an idea of what is happening in the hives. A base of reference, so to say.

Also, keep in mind the relative hive strength and the time of year. In a little while you get a data base to refer to.


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## snl (Nov 20, 2009)

I recommend exactly what you've written. I believe an OAV treatment gives you an excellent view of the mites residing in the hive. IMO it beats both the alcohol wash and sugar role as a mite determinant. It's easy, fast and effective.


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## enjambres (Jun 30, 2013)

There are, as far I know, no published thresholds to tell you what is a lot of mites, or even a tolerable level after a treatment, beyond the obvious. If the board is covered with dead 'uns you've got a problem. If only a dozen mites fall, do you have no problem, or have you had some technical defect in the treatment that failed to kill many?

And the other issue is that I think the rapid, short-term acidification of the entire hive environment if repeated merely for the purpose of checking the mite levels is too high a price to extract from the bees and all the commensal organisms living in the hive. These microorganisms almost certainly play an important role in overall bee health. The thing is we don't enough about them to know how to evaluate threats posed by our treatments.

I have no problems keeping very close tabs on my mites by sticky boarding every hive, every week, all year long (yes, even in the depths of a northern winter) and rotating through all of them during the warm months so some of the colonies in my yard are selected to be sugar rolled every week, and all of them take a turn about once a month. I don't focus so much on the numbers of mites on the boards, but I always know what my mite _level_ is: static, dropping, increasing, etc., relative to what it was a few weeks or a month ago. I think that's as important a thing to know as how are my brood numbers running. 

Given the human health risks of treating with OAV , even a single time, I would far rather do the simple, safe, work of sticky board insertion and assessment, or even regular sugar rolls (which take very little extra time if you do them a lot as part of your routine hive visits.)

Also repeated treatments that are not particularly lethal will select, over time, for mites that have a higher tolerance to it. This will weaken OA's current effectiveness against them.

In other areas of agriculture farmers have from time to time used pesticides as a monitoring method, so it's not a novel idea. But in general it has resulted in pretty much the same problems outlined above.

There is no free lunch, IMO.

Enj.


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## shinbone (Jul 5, 2011)

I always use the mite fall from an OAV treatment to determine if another treatment is warranted. Works really well.

The statements along the lines of "treat x times . . . " seem silly to me since it ignores whether the hive still has a significant number of mites. OAV'em until you have minimal mite fall is the best way.


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## soarwitheagles (May 23, 2015)

Wow, and I thought I was the only person using the mite drop count to monitor my hive...

I hope you don't think I am weird, but I check my hives every evening after applying an OAV.

There have been occasions when I will count 200-300 dead mites on a daily basis after a treatment. On the other hand, I have a hive now where not even one mite has fallen after a treatment.

So I am hoping I am obtaining at least an in the ballpark figure to guide me in my treatments as I diligently check the SBB on a daily basis.

I also do not want to go into the hive on a daily basis. I feel this can begin to disturb the bees, and I try to let them be as much as possible.

Finally, I am not so convinced we can even create mite resistance to OA. I have read repeatedly that OA is different than the use of other MAQ's.

Just my 0.02 cents.


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## snl (Nov 20, 2009)

Per Jennifer Berry, Entomologist and Honey Bee Lab manager for UGA on Oxalic Acid…..


“……………resistance will not be an issue. It'd be like a ****roach becoming resistant to a hammer.”


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## grozzie2 (Jun 3, 2011)

enjambres said:


> I have no problems keeping very close tabs on my mites by sticky boarding every hive, every week, all year long


Those hives we have on screened bottoms with a sticky board, the board is used to control ventilation, nothing more. The reason goes back to our first year with bees, everybody told us we needed to use screened bottom boards, then the sticky will tell us about mite loads. In mid August, I pulled the sticky out, and for the first time, saw an actual mite, count em, one mite on the board, so we assumed mite counts were low enough there was no need to do anything. This was back when we first started, had three colonies at the time, and they were treated more like pets than livestock. Over dinner the conversation came up, if we had a dog that came in the house with one flea, what would we do ? After dinner, I went back out and put the treatments into the hives. Next day, fresh clean sticky boards went in, then a day later I pulled them and started counting mites. I lost track of the count, but that didn't really matter, the number was north of a thousand when I lost track.

The lesson we took from that, *no mites on the sticky board means, we have good strong healthy mites* that are not falling off the bees.

I have half a dozen colonies in boxes that have the screened bottom board. I'll use the stickies this year to get an idea of what the mite fall is when we apply mite remedies to the hives. When we want specific counts, I'll use the alcohol wash, and the dead bees resulting from the wash, will be used for nosema counting. If the colony cannot survive the loss of 300 bees at that time of year, it's already dead, just doesn't know it yet.


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## enjambres (Jun 30, 2013)

Larry,

I have read Ms. Berry's writing before and with respect, I disagree with her imperfect analogy. 

I don't think mites will become "resistant" to OA, but I do think they may gradually develop a greater tolerance for it. Which may sound like the same thing, but it's not.

It stands to reason that incomplete, or below optimal strength treatment that leaves more mites alive after exposure to OAV will inevitably, over time, select for mites with innate, and possibly heritable traits that allow them to better survive the onslaught of the treatments. 

The end result is that it will take more frequent treatments, at shorter intervals, or at higher doses to achieve the same kill rate.

But an even greater risk in my mind is the effect that unnecessary OAV exposure may have on all the other living things within the hive eco-system. 

The core of the best pesticide strategies is using exactly enough (product/interval/dosage) to just exceed the level of effective threat reduction, not complete eradication. The idea of complete eradication is why Big-Ag has created such huge problems.

It's perfectly fine in my mind to use mite fall after a needed treatment to assess effectiveness of the treatment (and possibly to evaluate the need for additional doses at the end of the principal series). And I always do a follow-up sugar shake a few weeks afterward to make sure I've gotten the reduction I expected. But I think using a single dose simply as a monitoring tool to assess levels is misguided: it carries too high a cost to the hive for the benefit gained since it is easy to assess mite levels in other ways that carry no risks at all.

The information you gain from a testing dose of OAV is no higher quality than what you get from a sugar roll (or even sticky boarding). Neither method produces an absolute number of mites in the hive; each is just a way of counting the mites revealed by a certain technique, on a given day. So with the benefits being roughly equal, the advantage then goes to the technique with the least cost, and for that sugar rolls (or regular sticky boarding) carry the lower over biological cost to the colony. (Not to mention considerably lower human health risk, as well, even assuming correct use of personal protective gear.)

Enj.

Enj.


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## snl (Nov 20, 2009)

Nancy,
I don't see resistance or tolerance occurring due to OA. 20+years of use in Europe and absolutely nothing I can find shows any mite tolerance of OA. While JB's analogy is imperfect, it does impart an understanding that is plain to see. But you do have a point on it's effect on other microbes in the hive.... it's unknown. But the same can be said for all treatments.

However, I've 2 test hives that for the last 2 years, have OAV'd every time I went to the apiary just to see the result. They both STILL have the same marked queens (remarkable) and are doing great. 
When you OAV an mite infested hive, the bees afterwards are livelier and seem happier? It's as if a great burden was lifted from them. 

Point being, if it's ease of use and application gets beekeepers more involved with tending their hives...........i


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## Arnie (Jan 30, 2014)

No kidding, Larry? You OAV a couple hives every time you get near them? Awesome!

Isn't it an assumption that all the other organisms in a hive are beneficial, necessary; and also destroyed by OAV? Where's the evidence of all of that? Where's the evidence of resistance to OAV?

I'm not trying to start an internet flame war, but that's a lot of assuming being done.


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## dudelt (Mar 18, 2013)

Larry, I agree with what you stated regarding getting the beekeepers more involved with their hives. I believe testing with OAV is a tool, but not one that should be done too often. If it makes it easier to determine a mite load in the hive, with some accuracy, it is a useful tool. However, I will also disagree with Ms. Berry's assessment that resistance will not happen. It may not be likely, but it probably will happen if done long enough. The whole purpose of offspring coming from two parents is to vary the gene pool throughout the species. Biological forces do not want to create one super being, it is trying to create diversity so that under different environmental stresses at least some of the creatures survive. Since the nature of the stress cannot be determined ahead of time, many different offshoots must be created. If the OA is killing the varroa through piercing the feet, as has been suggested, all it will take is for them to develop a new variant on their feet to become resistant. While this is not as easy as it sounds, it does happen. What we call "birth defects" happens to all species. When the birth defect turns out to be beneficial to the species, a new possibly resistant mite may come into being. Maybe not this week, but eventually, it will happen.


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## snl (Nov 20, 2009)

dudelt said:


> If the OA is killing the varroa through piercing the feet, as has been suggested, all it will take is for them to develop a new variant on their feet to become resistant. While this is not as easy as it sounds, it does happen. What we call "birth defects" happens to all species. When the birth defect turns out to be beneficial to the species, a new possibly resistant mite may come into being. Maybe not this week, but eventually, it will happen.


My understanding, is that the OA enters thru the soft pads of the mite's feet into their bloodstream and in doing so changes their PH level thus eliminating them. I don't see a birth defect changing that process. Again, 20+ years of use and no resistance or tolerance. While one never says "never," 20+ years says a lot.


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## fqwx64 (Feb 3, 2016)

snl said:


> Nancy,
> ... I've 2 test hives that for the last 2 years, have OAV'd every time I went to the apiary just to see the result. They both STILL have the same marked queens (remarkable) and are doi...........i


How often do you go to the apiary?


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## snl (Nov 20, 2009)

fqwx64 said:


> How often do you go to the apiary?


From about April to October, about every 10-14 days.


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## enjambres (Jun 30, 2013)

I, too, don't wish to start a flame war over this issue, but...

The 20-years of use in Europe w/o developing issues may be 20 years of careful, thoughtful, by-the-book "therapeutic" use as compared with the idea under discussion here which would be the routine use of a single-shot dose of OAV as a monitoring tool. That's a whole 'nother thing.

I'm arguing that the cost/benefit analysis of that idea is tilted too far into the unknown (what does each and every use of OAV do to the invisible hive beasties?) and into the known effects of evolution. No matter how the chemical is absorbed into the mites' bodies, some mites will be less efficient absorbers just due to natural variation. And these are the mites that will survive and it is likely that they will pass that trait on down to their offspring, who will mate with the only mites alive after treatment (lower-absorbers, by definition), gradually evolving into a stronger and more persistent expression of the less-efficient absorption trait. And where will that lead?

Of course every use of OAV can result in this, but if it used at the published "therapeutic rate" (assuming it is based on scientific studies, not folklore) you're getting the maximum effective suppression at the least risk of promoting target species tolerance and the least harm to off-target organisms and systems.

Farmers are notorious for using barn-logic and adding a little more of this and that off-label use to their tank mixes and pest programs. And the chemical companies are only too glad to pile on - that's why, just to use one example, routine use of antibiotics (which promotes weight gain, as well as killing off diseases organisms) became commonplace in meat. It was easier, perhaps cheaper, to just add it to the feed. But the off-target consequences are not worth the costs, as we have found to our dismay.

And this may also be true with OAVing as a _monitoring_ technique. There are at least two excellent, easy, cheap, and if used intelligently (with understanding the of limitations and used regularly and conscientiously all season long) very reliable methods of monitoring mites: sticky boards and sugar rolls. These carry no risk to the operator and either no, or very low, risk to hive.

The number of mites dropped by a single OAV is no more "accurate" than the number of mites dropped every week on a board or rolled out of your bees with powdered sugar. All are simply sampling methods that give you a snapshot of the phoretic mite numbers at the moment or period of testing. It's the comparisons of those numbers with other similarly-derived numbers (published thresholds specific to the test, or even better, what your mite numbers were last week or two weeks ago or last month.) that make monitoring an effective tool This isn't the kind of test where you are seeing if you have mites, like you might be doing if you had your blood tested for, say, ZIKA virus. It's not a do you /don't you have mites issue. If you've got live bees, you've got mites - you don't need to test for that.

Since it isn't an absolute, yes or no, kind of situation, you are just _assaying_ the phoretic mite population growth rates and rate of change over time. In which case any test that is repeated often enough to get reliably comparable results will do just fine. But sticky boarding done once in awhile, or sugar rolling a couple of times per season will only give you factoids. Accurate-enough numbers (if done properly) but essentially meaningless numbers whether low or high or in between.

You have to do the tests repeatedly, at short intervals to have a good idea of what the trends are. 

Even doing a single round of OAV is only going to tell you how many phoretic mites are in the hive at the time of the test (and for shortly thereafter) - and the amount of phoretic mites varies considerably across the seasons, and likely day to day. It has the same low-counting bias of a sugar roll or sticky board. It's not an improvement in quality over the other tests.

The argument that is often made, "well, I put in a sticky board or did a roll and then did an OAV and the numbers of mites seen were much higher" is simply invalid. None of these test should be compared to each other. All should only be compared to similar, regular, test results by the same method. 

Now, I would certainly be open to reading a study that discovered that an alternative mite control technique might be regular single dose applications of OAV through out the season, with tolerable affects of colony health and off-target species. Perhaps routine reductions of phoretic adults using a multiple single doses of OAV is effective, in the long run, to keeping mites below a damaging threshold. But as far as I know no one has studied this issue (and since the chemical is not sponsored by commercial interests we'll have wait for academic research to do this.) Until that's done, however, it's a risk I am not willing to take on my own.

Larry, I am glad your "old" queens are doing well, but why is two years so impressive? Two of my three original queens are starting their _fourth_ season with me. (Realistically, I know it may be their last summer > sniff<) And they were all swarm queens when they arrived here so possibly even a year old than that. They are marked, so I am not confusing them with younger replacements. I attribute part of their longevity to effective, long-term, mite suppression with OAV using your equipment, of course. But I combine that with vigilant monitoring so I can use the least number of treatments and at the most carefully chosen times of the year. 

Enj.


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## snl (Nov 20, 2009)

enjambres said:


> Larry, I am glad your "old" queens are doing well, but why is two years so impressive?


Nancy, I'll answer more later. Heading off the SCBA conference. The reason I'm impressed by the 2 year old queens is that I've vaporized those 2 test hives, what maybe 100 times or better over the last two years and those queens are alive and doing well (at the moment). So, I can say for certain that for at least 2 bees (the queens), OAV has no ill effect......


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## Arnie (Jan 30, 2014)

And there you have it; we will just have to agree to disagree. 

Luckily for you, it may ease your mind to know that I am now in my twilight years and likely won't be around long enough to produce the dreaded 'super mite'--- Mighty Mite?--- with my reckless OAV-ing .

Anyhow, I will continue to cheerfully kill mites and count the cadavers for as long as I can.

One other thing about queens:
When I had bees back in the pre-mite days I never experienced or heard of much queen trouble. Sure, once in a while a queen would fail, but not very often. And they could lead a hive for 3 years or more. I really think the mites are having an effect on queens these days.


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## mgolden (Oct 26, 2011)

The available treatments is not very extensive. I think OAV and Apivar are the two that work well.

I don`t think it is wise to misuse these or have a treatment program that could lead to resistance.

Hence, apply dosage as recommended.

Rotate the treatment. Apivar in spring and OAV in fall.

Don`t be applying OAV every two weeks to do a mite count.


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## Arnie (Jan 30, 2014)

So if I use the recommended dose of 2 grams when I do a treatment, count the dead mites to assess if further treatments are warranted, I am OK?

I may do this in a month to determine if a round of treatments this spring would be needed. Am I wrong to do so?


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## dudelt (Mar 18, 2013)

mgolden said:


> The available treatments is not very extensive. I think OAV and Apivar are the two that work well.
> Don`t be applying OAV every two weeks to do a mite count.


I could not agree with you more. I am currently doing a fall treatment of either MAQS or Apivar and a winter treatment of OAV. The winter treatment does a real nice job of being sure there is a clean start to the spring that I can't see doing whole lot of monitoring until June and then maybe monthly thereafter. I may look earlier just to be sure my thoughts are correct. 

Arnie, In my opinion, if you do a treatment next month and find very few mites, I would not check again for 2-3 months. If you have a bunch, definitely do a total of 3-4 OAV treatments to wipe out those buggers. Or, do a round of Apivar. In my area, I do not see a huge build up until mid July - August. I can say from experience in my yard that if I don't treat in August, they will be dead by the new year.


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## Arnie (Jan 30, 2014)

Ya know, the more I think about it, I am starting to think that snl's program of a round of treatments in spring, another round when supers come off in late summer, and a single dose in late November/early December is the way to go. That's what I did in 2015 and for the first time in a number of years the bees look like they did pre mites. Before using OAV we struggled with the strips and that white goo you put on the top bars and the bees just didn't do as well. 
Now all the hives are happy, building up like gangbusters. 

So I guess the idea is .... don't let the mites build up at all and the bees will be happy. And if the bees are happy, I'm happy. 

Thanks for the thread, it helped me think it through.
Now I don't have to mess around with one-off treatments; we can clean up the mites in spring, after the flow, and again at winter brood break. I'll monitor the kill levels after the treatment rounds, and as I go along during the year on a weekly/monthly basis. 

That'll be the plan for 2016.


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## beepro (Dec 31, 2012)

You will not get an accurate mite count using the oav method or
any other methods at the down bee trend. You see, I have been using my homemade oav
gadget since last year to both treat and monitor the mite cycle
in the hives.
The problem is once all the mites are inside the capped cells your
mite level will be lower than usual when compare to the new bee
hatched cycle. So the mite count level goes with the bee cycle in
up and down. The bottom line is to get an accurate mite count you have
to do it at the bee's hatch time when most of the free running mites are
with the newly hatched bees. 
So yes, it is possible to get an accurate mite count and monitor the
mites using the oav method but ONLY at the right timing. I will continue
to use my oav gadget to not let the mites take a foothold. Treated once
in late October and once this early Spring before the flow. Now almost all
mite free at 99% in one of the growing hives.


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## rookie2531 (Jul 28, 2014)

What are you referring to beepro, the early winter? (Down bee trend)


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## honeyforsalebest (Nov 27, 2014)

thanks


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## beepro (Dec 31, 2012)

Yep, the early winter and early Spring time
build up too. In a normal growing hive you
cannot see the down bee trend. But in a small
nuc you can see the rise and fall of the mite cycles
according to the newly hatched young bees. The
most effective treatment time is when the bees
hatched with the free running mites on them.


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## sc-bee (May 10, 2005)

beepro said:


> The problem is once all the mites are inside the capped cells your
> mite level will be lower than usual when compare to the new bee
> hatched cycle. So the mite count level goes with the bee cycle in
> up and down. The bottom line is to get an accurate mite count you have
> ...


Same with any monitoring method right...alcohol wash..sugar roll... sticky board


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## sc-bee (May 10, 2005)

enjambres said:


> Also repeated treatments that are not particularly lethal will select, over time, for mites that have a higher tolerance to it. This will weaken OA's current effectiveness against them.


*>>>How does Oxalic Acid kill mites?*

The jury is still out. It is thought that OA vapors enter through the soft pads of the mite’s feet and travels to the blood stream, killing the mite. It is also thought that it destroys parts of the mite’s mouth. However it works, it decimates mites.<<<

If the OA indeed burns off the soft mouth tissue parts, which is not an EXOSKELETON as in bees, then it would indeed be hard to breed selectivity... don't you think?


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