# Wow! I am noticing a big difference between Apivar & OA vaporization results. Why?



## Rusty Hills Farm (Mar 24, 2010)

*Re: Wow! I am noticing a big difference between Apivar & OA vaporization results. W*

Because OA treats phoretic mites only. The most effective time to treat with OA is when there is no brood in the hive because the mites hide/reproduce inside the brood cell where OA cannot reach them.

Rusty


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## sjj (Jan 2, 2007)

*Re: Wow! I am noticing a big difference between Apivar & OA vaporization results. W*



soarwitheagles said:


> “I had started up with the OA vaporization three weeks ago on an every 5 days basis.
> We saw 10-30 mites dropping per day.
> 
> Fast forward to 4 days ago.
> ...


The procedure described above is known for its ease of use and can be done with ease always.


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## mbevanz (Jul 23, 2012)

*Re: Wow! I am noticing a big difference between Apivar & OA vaporization results. W*

Rusty, Apivar only kills the phoretic mites as well. I am convinced that Apivar is quite effective. I am not at all convinced on OAV. 
And for me, piece of mind is very important in beekeeping.


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## Richard P (Feb 12, 2016)

*Re: Wow! I am noticing a big difference between Apivar & OA vaporization results. W*

HMMMMMM.... Got me 2nd. guessing now. I ordered strips a week ago for my hives, and then decided that OA was the best way to go from what all I have heard and read, so that is what my plan is. Now I am not sure which way to go. This is tough stuff sometimes, LOLOL... I was gonna offer my box of strips for sale cheap at our next meeting, and run with the OA. Now what!....


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## mbevanz (Jul 23, 2012)

*Re: Wow! I am noticing a big difference between Apivar & OA vaporization results. W*

I think the key is to check to see if the treatment is working. Use one of the many mite counting methods before treatment, and then during treatment.


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## snl (Nov 20, 2009)

*Re: Wow! I am noticing a big difference between Apivar & OA vaporization results. W*

There is no doubt that OAV kills the phoretic mites, that's been proven over and over. It does not kill the mites in the brood. When bees are flying and in such a large hive as yours, the bees carry out the reformed crystals almost immediately (and it does not get a chance to kill mites) as they (the bees) see it (the reformed crystals) as a foreign substance. There are better treatments than OAV for mites in a very high populous hive with lots and lots of brood, Apivar is one of them.


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## aunt betty (May 4, 2015)

*Re: Wow! I am noticing a big difference between Apivar & OA vaporization results. W*

Not sure that picking one and saying it's best...then sticking to that treatment is such a good idea. 
Timing, weather, strength of colony, and mite load all would affect your selection of what product to use. 
Certainly not an expert but am learning as much as I can about all forms of mite treatments.
I think a good beek would have MAQ's, OAV, Apivar, and possibly some other tools in his mite arsenal. Know when and when not to use them all.

It's not "pick one".


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## Dan the bee guy (Jun 18, 2015)

*Re: Wow! I am noticing a big difference between Apivar & OA vaporization results. W*

I was searching YouTube yesterday and found a video made by Dan purvis he caged the queen for two weeks then opened the candy plug then waited another week to ten days then he treated with OAV so all the mites were out of the brood. I would say he is a good one to listen to.


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## Mike Gillmore (Feb 25, 2006)

*Re: Wow! I am noticing a big difference between Apivar & OA vaporization results. W*



soarwitheagles said:


> I had started up with the OA vaporization three weeks ago on an every 5 days basis. We saw 10-30 mites dropping per day.
> .... Why wouldn't the OA vapor give us more dead mites?


That's a great question. On a large populous hive, even with just a minor mite infestation, those mite counts seem extremely low following OAV. 

Could you provide detail on your vaporization method.


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## enjambres (Jun 30, 2013)

*Re: Wow! I am noticing a big difference between Apivar & OA vaporization results. W*

Is it safe to use a total of six Apivar strips in the hive at one time? I don't use Apivar, but when I looked at the instructions on line, the chart provided indicated that for 16, or more, (my emphasis) frames of bees the dose was four strips. 

I run big hives, too, but I think it is risky to just extrapolate pesticide doses beyond the labeled ones for typically-sized colonies without contacting the manufacturer.

Apivar seems (from what I read online) to have a pretty good safety record, even at higher (unlabeled) doses, but I would still contact the supplier/distributor on Monday. 

The large drop may be a result of the 50% excess dosage in use.

Enj.


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## snl (Nov 20, 2009)

*Re: Wow! I am noticing a big difference between Apivar & OA vaporization results. W*



Mike Gillmore said:


> That's a great question. On a large populous hive, even with just a minor mite infestation, those mite counts seem extremely low following OAV.
> 
> Could you provide detail on your vaporization method.


I agree Mike. I'd like to hear the answer as well. But again with an extremely populous hive, those reformed crystals are being carried right out, hardly having had a chance to work. However, 10-30 seems very low........


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## Colino (May 28, 2013)

*Re: Wow! I am noticing a big difference between Apivar & OA vaporization results. W*



aunt betty said:


> I think a good beek would have MAQ's, OAV, Apivar, and possibly some other tools in his mite arsenal. Know when and when not to use them all.
> 
> It's not "pick one".


Absolutely! If you use Apivar only/always you will develop resistant mites. I use a rotating regimen of mite treatments both organic and synthetic.


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## Mike Gillmore (Feb 25, 2006)

*Re: Wow! I am noticing a big difference between Apivar & OA vaporization results. W*



snl said:


> But again with an extremely populous hive, those reformed crystals are being carried right out, hardly having had a chance to work. However, 10-30 seems very low........


If he gets a 300 count drop the day after inserting the strips, those are all phoretic mites at that point. The rest are still under cappings. 

He "should" also be getting a similar count with OAV, at least after the first day or two.


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## wildbranch2007 (Dec 3, 2008)

*Re: Wow! I am noticing a big difference between Apivar & OA vaporization results. W*



Dan the bee guy said:


> I was searching YouTube yesterday and found a video made by Dan purvis he caged the queen for two weeks then opened the candy plug then waited another week to ten days then he treated with OAV so all the mites were out of the brood. I would say he is a good one to listen to.


he's located in Tenn. last I knew, did he indicate the time of year he did it, you would be taking 3-4 weeks of new bees out of you hive, what would that do to your honey production, and depending when you did it, your overwintering?


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## Dan the bee guy (Jun 18, 2015)

*Re: Wow! I am noticing a big difference between Apivar & OA vaporization results. W*



wildbranch2007 said:


> he's located in Tenn. last I knew, did he indicate the time of year he did it, you would be taking 3-4 weeks of new bees out of you hive, what would that do to your honey production, and depending when you did it, your overwintering?


I would have to find it again to see .


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## Groundhwg (Jan 28, 2016)

*Re: Wow! I am noticing a big difference between Apivar & OA vaporization results. W*



Dan the bee guy said:


> I was searching YouTube yesterday and found a video made by Dan purvis he caged the queen for two weeks then opened the candy plug then waited another week to ten days then he treated with OAV so all the mites were out of the brood. I would say he is a good one to listen to.


Not sure which would be worse mites or 21 days with our brood being laid or raised.


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## Dan the bee guy (Jun 18, 2015)

*Re: Wow! I am noticing a big difference between Apivar & OA vaporization results. W*



wildbranch2007 said:


> he's located in Tenn. last I knew, did he indicate the time of year he did it, you would be taking 3-4 weeks of new bees out of you hive, what would that do to your honey production, and depending when you did it, your overwintering?


The video was posted October he mentioned doing it after pulling your honey. The Chanel Dannpurvis he has all the links below


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## Rusty Hills Farm (Mar 24, 2010)

*Re: Wow! I am noticing a big difference between Apivar & OA vaporization results. W*



mbevanz said:


> Rusty, Apivar only kills the phoretic mites as well. I am convinced that Apivar is quite effective. I am not at all convinced on OAV.
> And for me, piece of mind is very important in beekeeping.


I've never used Apivar, which is why I didn't comment on it. I have, however, used OAD with excellent results. The combination of VSH genetics and OAD seems to be a good one for me. I believe it was Randy Oliver's site where I read that OAD when there is no brood results in a 90% mite kill in the fall, and in the spring when there is apt to be brood in the hive the efficacy is about 50%. That combined with bees who are hygienic (even when it's not a high rate) seems to knock the mites way down. I've been using this combination since about 2012 and have not lost a hive to mites in that time, altho I have had a couple of hives that really dropped 'em on the final treatment of that first year. I've also had a few that needed no treatment at all in that same time frame, so I feel I am making progress here.

I still haven't found an alternative for the OAD, which I would really like to have, since I believe in rotating treatments.

JMO

Rusty


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## wildbranch2007 (Dec 3, 2008)

*Re: Wow! I am noticing a big difference between Apivar & OA vaporization results. W*



Dan the bee guy said:


> The video was posted October he mentioned doing it after pulling your honey. The Chanel Dannpurvis he has all the links below


so in my area I would be shutting the queen down for the month of Sept. don't think it would work to well up north, and we don't get a lull in the middle of the summer, how about you?


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## soarwitheagles (May 23, 2015)

*Re: Wow! I am noticing a big difference between Apivar & OA vaporization results. W*



Mike Gillmore said:


> That's a great question. On a large populous hive, even with just a minor mite infestation, those mite counts seem extremely low following OAV.
> 
> Could you provide detail on your vaporization method.


Mike, I am happy to provide the details of our OA vaporization method.

1. I do the vaporizing at night because then I know all of the bees are at home.

2. I seal up _everything_ with wet while towels. I can see very tiny amounts of vapor escape during treatment, but it is so small of an amount, I don't worry about it.

3. I usually load one half full teaspoon of OA into the vaporizer depending upon the size of the hive. On this hive, three boxes of bees, so I normally use 3/4 of a teaspoon, but chose to up the dose to a full teaspoon [ 3 grams] during the last three treatments].

4. I insert the vaporizer into the feeding slot on the bottom, then seal off the SBB so no vapor can leak out. I do see tiny amounts of vapor leaking out the top of the top box. I did do an experiment once with the top off, and massive amounts of vapor rise right up through all three boxes. So I know the vapor is hitting all two/three levels.

5. I discovered all the OA is vaporized right at the 2 minute mark, but for good measure, I leave the vaporizer on for 135 seconds and now I consistently achieve a full vaporization of the OA with no residue.

6. I leave the hive alone for 10-12 minutes, still sealed and undisturbed.

7. After the waiting period, I carefully remove all the wet towels and the vaporizer.

8. I put all my equipment away, hoping I killed all mites that are not inside the cells on larvae.

Please let me know if I am doing something wrong or if there is something I can do to make the OA treatment more effective.



enjambres said:


> Is it safe to use a total of six Apivar strips in the hive at one time? I don't use Apivar, but when I looked at the instructions on line, the chart provided indicated that for 16, or more, (my emphasis) frames of bees the dose was four strips.
> 
> I run big hives, too, but I think it is risky to just extrapolate pesticide doses beyond the labeled ones for typically-sized colonies without contacting the manufacturer.
> 
> ...


Enj,

*My Apivar strips directions state "Two strips per brood chamber."*

I followed the Apivar label instructions exactly as they stated them.



snl said:


> I agree Mike. I'd like to hear the answer as well. But again with an extremely populous hive, those reformed crystals are being carried right out, hardly having had a chance to work. However, 10-30 seems very low........





Mike Gillmore said:


> If he gets a 300 count drop the day after inserting the strips, those are all phoretic mites at that point. The rest are still under cappings.
> 
> He "should" also be getting a similar count with OAV, at least after the first day or two.


Yes, I was thinking for the last 3 weeks, the OAV was keeping my hives healthy by killing all mites not under the cell caps...

But after installing the Apivar, I am seeing a massive difference. 

So in review:

Three treatments of OAV, every 5 days, in the last 2-3 weeks. Mite drops were 10-30 per day.

Installed Apivar after three OAV treatments, and after 24 hours, seeing 300+ mites drop dead per day. This is now 4 days in a row of 300+ dead mites per day. Man, what is going on here?

*Can anyone here help me understand why this is happening?*

Thanks!

PS I was reading Randy Oliver's website again last week, and he clearly indicates that NOW is the time to apply Apivar in his locale [I am an hour away from Randy]. Now I am glad I read and reread his charts and advice. I think it is possible I would have lost my one and only healthy bee hive if I did not treat with the Apivar according to Randy's suggestions...

Here is the exact page I am referring to:

http://scientificbeekeeping.com/first-year-care-for-your-nuc/

Soar

Here's the Apivar instruction label:









Here's Randy's Varroa mite treatment chart


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## Barhopper (Mar 5, 2015)

*Re: Wow! I am noticing a big difference between Apivar & OA vaporization results. W*

How has your brood build up been. Possibly a big hatch before the Apivar?


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## mbevanz (Jul 23, 2012)

*Re: Wow! I am noticing a big difference between Apivar & OA vaporization results. W*

The apivar is to stay in about 6 weeks and is a slow/low release. You are likely seeing mites that were under the capped brood. If there were 3 mites in a single capped brood cell, you only need 100 bees to hatch in the previous 24 hours to see a 300 count on the sticky board.

As far as 2 strips per brood chamber Id read the label fully. You will see a chart based on the number of brood frames. This time of year (or about 3 weeks ago) in Indiana, we only need 1 strip as most hives have less than 5 frames of brood.


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## Dan the bee guy (Jun 18, 2015)

*Re: Wow! I am noticing a big difference between Apivar & OA vaporization results. W*



wildbranch2007 said:


> so in my area I would be shutting the queen down for the month of Sept. don't think it would work to well up north, and we don't get a lull in the middle of the summer, how about you?


I was thinking about pulling the queen out in the beginning of August putting her in a 5 frame nuc then letting the hive requeen its self . I thought treating the way he did it would fit perfectly with my plan.


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## dadux (Feb 23, 2012)

*Re: Wow! I am noticing a big difference between Apivar & OA vaporization results. W*

Soar, Did you block off the SBB for the OA treatment?


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## LeonardS (Mar 13, 2012)

*Re: Wow! I am noticing a big difference between Apivar & OA vaporization results. W*



dadux said:


> Soar, Did you block off the SBB for the OA treatment?


Yes, he said that he did block off the SBB.


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## soarwitheagles (May 23, 2015)

*Re: Wow! I am noticing a big difference between Apivar & OA vaporization results. W*



Barhopper said:


> How has your brood build up been. Possibly a big hatch before the Apivar?


Barhopper, Exactly! I estimate the queen was laying over a thousand eggs per day, on good days, even more than that. She has no stopping sense. Also, the bees were producing massive amounts of wax, faster than I have ever seen. Not exactly how they can produce so much in such a short amount of time. Saw excellent patterns of brood, pollen, and honey. I put on a 4th box with 10 new frames because they were working so fast, we realized there was no room left.



mbevanz said:


> The apivar is to stay in about 6 weeks and is a slow/low release. You are likely seeing mites that were under the capped brood. If there were 3 mites in a single capped brood cell, you only need 100 bees to hatch in the previous 24 hours to see a 300 count on the sticky board.
> 
> As far as 2 strips per brood chamber Id read the label fully. You will see a chart based on the number of brood frames. This time of year (or about 3 weeks ago) in Indiana, we only need 1 strip as most hives have less than 5 frames of brood.


mbevanz,

Very good points. Thank you! When JRG came over, I think we were seeing up to 6 mites per capped brood on some of them. It was awful. 

Oh no! I placed the Apivar according to frames of full bees, not according to frames of brood. I will read the label again.

EDIT: OH CRAP! You are right! I based my count according to frames full of living bees, not according to brood. What should I do now and is it possible I have poisoned my only healthy hive?



dadux said:


> Soar, Did you block off the SBB for the OA treatment?


Completely sealed. I accomplished this by placing a regular bottom board under the SSB, then sealing the entrance. No possible way for leaks that way.


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## beepro (Dec 31, 2012)

*Re: Wow! I am noticing a big difference between Apivar & OA vaporization results. W*

Why would I only see 10-30 dead mites daily using the OA vapor vs. the 300+ dead mites per day using the Apivar?
Because the mites are every where given the height of these hives. The free running mites are not
only on the newly hatched bees but also on the nurse bees and foragers. They can travel on the comb from one bee to the next. Once they find the broods then the next mite cycle can begin again.
The only way is to make the hive smaller and oav them at the before and after hatch cycle. Not all the bees will be covered with the oav (crystals) given the bee density and height of the hives. No maximum oav coverage! The Apivar is more uniform in strength when you put them in
certain spot of the hive.

Why wouldn't the OA vapor give us more dead mites? No maximum oav coverage give the high density
of the bees on the Spring expansion. The timing is off on every hatch cycle to oav them. 

Is there anything we can do differently to ensure we do not lose this hive to the Varroa mites?
Yes, there are many more way to do this. Use the amitraz (apivar) solution on the bees. Isolate
the queen to limit her brood area and then oav or Apivar the remaining no brood frame of bees. Make a split using mated queens. Plant honey producing plants in the summer. Install one of my homemade oav gadget under the hive for maximum oav delivery. This is my 4th years into beekeeping. Finally I have bees for Spring expansion and honey to harvest this season. And don't forget to get the no treat mite resistant bees too. This is 80% of the solution already.


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## BernhardHeuvel (Mar 13, 2013)

*Re: Wow! I am noticing a big difference between Apivar & OA vaporization results. W*

Just shaking my head.

What kind of vaporizer did you use? Is it one of those self-made ones? 

Also where did you get the 5 day apart from? Only three times? With brood present? Are you serious??? 

1. In tests here in Europe they've found most of the vaporizers aren't effective. The Varrox showed a 90 % efficiency, the others only 60 %. That is because most vaporizers do not vaporize (sublimate to be more accurate) but instead burn the oxalic acid. If you burn all the oxalic acid you get a nice fume, but that is as effective to kill mites as using your smoker. 

2. With lots of brood present you need another interval to make OAV working. Three days apart(!), six times at least. Check again and treat a seventh time if necessary. Mites are not stupid, they hide away in cells when they are about to be killed. So you need to repeat the treatment more frequently. With the right vaporizer you don't harm the bees at all. 

So get a decent vaporizer, pure oxalic acid and repeat the test. I am not having an opinion here, I know by longterm experience that the sublimation of oxalic acid is very effective, even with brood present. It is not easier and it is not dumb proof, but on the other hand you don't have carcinogenic degradation by-products in the hive. Especially if you treat in Spring(?) what is completely out of question here where I live to guarantee a high quality honey. Also the treatments work better in autumn and with a good autumn treatment you get better wintering results. Spring is simply way too late to treat. You better cut the first two sets of drone brood and have a great reduction in varroa mites which should be enough until the summer treatment.

@SNL: If the bees carry out the oxalic acid crystals it doesn't matter. The mites receive the crystals in a minute and stick to their feet as described here: http://www.beesource.com/forums/sho...out-lega-vaporizer-unit&p=1388906#post1388906


Treat with 1-2 grams of oxalic acid. Let the vapor circulate in the hive for a minute or two. The bees do all the fanning. Open up the screened bottom board after five minutes or so, so all the mites that drop, will drop out of the hive and not return into the broodnest after the crystals suck themselves into the mite. 

Repeat every three days for six-seven times. If you have a good vaporizer, the bees won't be harmed. (A friend tried the extreme to find the highest treatment dosage, he treated 25 times in a row, three days apart...the bees wintered just fine and strong. :thumbsup Bees do get harmed if the oxalic acid is burned rather than sublimated.

There is a fool-proof vaporizer which produces good and reliable results. It is the Oxamat. You should try to import it through one of your bigger beekeeping suppliers like Mannlake or so. 





https://www.youtube.com/watch?v=-HZ6u8Bkoew

This device has a temperature control, so the sublimation is perfectly done. It has a fan, that circulates the vapor throughout the hive. Works like a charm and as said, very reliable. Bees winter great!


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## mbevanz (Jul 23, 2012)

*Re: Wow! I am noticing a big difference between Apivar & OA vaporization results. W*

i doubt you poisoned them. The strips are slow release. Just get in and take all out except what is needed based on the number of brood frames. Id go back in a week and see how the brood looks. See if you have new eggs.


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## missybee (Sep 6, 2014)

*Re: Wow! I am noticing a big difference between Apivar & OA vaporization results. W*

BernhardHeuvel. Thanks for the good write up. We are going to increase our treatments. One of our hives is booming out of the seams, the others are getting going.


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## snl (Nov 20, 2009)

*Re: Wow! I am noticing a big difference between Apivar & OA vaporization results. W*



BernhardHeuvel said:


> Also where did you get the 5 day apart from? Only three times? With brood present? Are you serious???
> 
> 1. In tests here in Europe they've found most of the vaporizers aren't effective. The Varrox showed a 90 % efficiency, the others only 60 %. That is because most vaporizers do not vaporize (sublimate to be more accurate) but instead burn the oxalic acid. If you burn all the oxalic acid you get a nice fume, but that is as effective to kill mites as using your smoker.
> 
> 2. With lots of brood present you need another interval to make OAV working. Three days apart(!), six times at least. Check again and treat a seventh time if necessary. Mites are not stupid, they hide away in cells when they are about to be killed. So you need to repeat the treatment more frequently. With the right vaporizer you don't harm the bees at all.


Bernard, why the 3 days apart, 6 times at least? OA will remain in the hive for days (who knows how many, but from what I've gathered certainly longer than 3) after vaporization. The mite, when it emerges will remain phoretic (according to many) approx 5 days). So if you vap on day 1, any mite emerging on days 2-4 (after vaporization) will come into contact with the remaining OA crystals, and die.


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## Mike Gillmore (Feb 25, 2006)

*Re: Wow! I am noticing a big difference between Apivar & OA vaporization results. W*



soarwitheagles said:


> ....Please let me know if I am doing something wrong or if there is something I can do to make the OA treatment more effective.


Your method sounds pretty solid to me. 

Just a few quick questions. What were the temperatures when you vaporized? Where did you get your OA from? What model vaporizer are you using?


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## BernhardHeuvel (Mar 13, 2013)

*Re: Wow! I am noticing a big difference between Apivar & OA vaporization results. W*



snl said:


> ... any mite emerging on days 2-4 (after vaporization) will come into contact with the remaining OA crystals, and die.


They won't. You can get into serious trouble if you do a summer treatment 5 or 7 days apart. In summers with a low varroa population you might get away with it, but in some years you'll see many crashing hives in autumn. 

The remaining crystals do break down quickly and aren't effective enough to kill the mites. If you leave windows, time windows for the mites to escape through, you'll be in trouble one day. The 3 days frequency is a proven method with brood present. I can only recommend it. But don't blame oxalic acid vaporization. 

In studies it was found that the half life of oxalic acid (dribbled though) in a hive is two weeks. So in a month it should be all gone. Problem is, the sublimated oxalic acid binds quickly to all humidity, be it in the air, on the comb or at the mite's feet. So what you get is droplets of oxalic acid anywhere in the hive. I don't think the mites will walk into a drop of oxalic acid, but rather avoids it. One of the behaviour is, to descend down into a broodcell about to be capped to escape the tricky situation. Bottom line is for me at least, OAV is effective only for minutes. There is no longterm effect.


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## LeonardS (Mar 13, 2012)

*Re: Wow! I am noticing a big difference between Apivar & OA vaporization results. W*

So, 3 treatments on 7 day intervals is no longer sufficient? Are you suggesting 7 treatments on 3 day intervals?


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## Mike Gillmore (Feb 25, 2006)

*Re: Wow! I am noticing a big difference between Apivar & OA vaporization results. W*



BernhardHeuvel said:


> Bottom line is for me at least, OAV is effective only for minutes. There is no longterm effect.


Unless you can provide a study to support this, I will have to respectfully disagree with you. 

For several years I've been treating with OAV 3 times - 7 days apart in August/September and it has been extremely effective for me. After a treatment, the mite drops are very high for 2-3 days following the treatment, then it quickly drops back down to normal pre-treatment numbers. If the effectiveness was only for "minutes" this would not be happening. There has to be some kind of residual effect that continues to kill the mites for a few days following treatment. 

Soar may be having a problem right now because the mite load was already very high when the colony went into rapid brood expansion and most of the mites ended up in capped cells on the first major round of brood, when he was treating with OAV. When he started the strips perhaps all of those protected bees with their accompanying mites were now phoretic. Maybe if he was treating right now with OAV instead of Apivar he might be getting 300 mites with the AO as well. I don't know, only guessing. This has me stumped.


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## RayMarler (Jun 18, 2008)

*Re: Wow! I am noticing a big difference between Apivar & OA vaporization results. W*

This is slightly off topic, but I am just wondering, what happens when the varroa mite evolves to having barbed feet instead of stick pads...


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## snl (Nov 20, 2009)

*Re: Wow! I am noticing a big difference between Apivar & OA vaporization results. W*



RayMarler said:


> This is slightly off topic, but I am just wondering, what happens when the varroa mite evolves to having barbed feet instead of stick pads...


Not sure they will, but they haven't in 20+ years of OA use............


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## Mike Gillmore (Feb 25, 2006)

*Re: Wow! I am noticing a big difference between Apivar & OA vaporization results. W*

Apivar stock will go through the roof.


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## mbc (Mar 22, 2014)

*Re: Wow! I am noticing a big difference between Apivar & OA vaporization results. W*



Mike Gillmore said:


> Unless you can provide a study to support this, I will have to respectfully disagree with you.
> 
> For several years I've been treating with OAV 3 times - 7 days apart in August/September and it has been extremely effective for me. After a treatment, the mite drops are very high for 2-3 days following the treatment, then it quickly drops back down to normal pre-treatment numbers. If the effectiveness was only for "minutes" this would not be happening. There has to be some kind of residual effect that continues to kill the mites for a few days following treatment.
> 
> Soar may be having a problem right now because the mite load was already very high when the colony went into rapid brood expansion and most of the mites ended up in capped cells on the first major round of brood, when he was treating with OAV. When he started the strips perhaps all of those protected bees with their accompanying mites were now phoretic. Maybe if he was treating right now with OAV instead of Apivar he might be getting 300 mites with the AO as well. I don't know, only guessing. This has me stumped.


I've always assumed the mites get the initial hit from oav but some take a while to die, rather than "new" mites emerging and being exposed to residual oa.


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## AHudd (Mar 5, 2015)

*Re: Wow! I am noticing a big difference between Apivar & OA vaporization results. W*



BernhardHeuvel said:


> In studies it was found that the half life of oxalic acid (dribbled though) in a hive is two weeks. So in a month it should be all gone.


If the half life is two weeks, in a month there will be 25% left. In two more weeks there will be 12.5% and so on. At least that is my understanding when the term is used to describe how long radioactive materials last.

Alex


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## snl (Nov 20, 2009)

*Re: Wow! I am noticing a big difference between Apivar & OA vaporization results. W*



BernhardHeuvel said:


> T Bottom line is for me at least, OAV is effective only for minutes.


Sorry Berhard, I don't agree. I'm with MG on this. I know what I've seen and that is the same as Mike has mentioned and it's what BioVet, the maker of the Varrox also states. The question for me (and I'm guessing that it depends on the size of the hive (#of bees flying)) is how long OA remains in hive for the mites to absorb. I've looked inside a hive right after OAV and the OA crystals cover everything, so to state that it works for only minutes is beyond what I see.......


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## enjambres (Jun 30, 2013)

*Re: Wow! I am noticing a big difference between Apivar & OA vaporization results. W*

@Soar:

I would go back and take out the excess strips. That chart on the label is what I saw when I Googled the instructions (because I don't use that treatment, and didn't know). That's why I asked you that question when you said you had six strips in the hive.

But when doing more research (to decide how much I should fuss at you over the extra strips) I found that they have done tests and found it pretty safe even at much higher doses (up to five times recommended dose.) So I don't think you have killed off your hive. But perhaps just added to their short-term stress, which is why I'd get them out ASAP. (They will need careful disposal since they still have a lot of chemical on them, don't just dump them in the trash.)

It will be interesting to see if the mite fall immediately drops when you've got the strips down to the correct number.

Enj.


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## soarwitheagles (May 23, 2015)

*Re: Wow! I am noticing a big difference between Apivar & OA vaporization results. W*



Mike Gillmore said:


> Unless you can provide a study to support this, I will have to respectfully disagree with you.
> 
> For several years I've been treating with OAV 3 times - 7 days apart in August/September and it has been extremely effective for me. After a treatment, the mite drops are very high for 2-3 days following the treatment, then it quickly drops back down to normal pre-treatment numbers. If the effectiveness was only for "minutes" this would not be happening. There has to be some kind of residual effect that continues to kill the mites for a few days following treatment.
> 
> Soar may be having a problem right now because the mite load was already very high when the colony went into rapid brood expansion and most of the mites ended up in capped cells on the first major round of brood, when he was treating with OAV. When he started the strips perhaps all of those protected bees with their accompanying mites were now phoretic. Maybe if he was treating right now with OAV instead of Apivar he might be getting 300 mites with the AO as well. I don't know, only guessing. This has me stumped.


Mike,

I didn't think about it until I read your statements above. You know, what you said sure makes a lot of sense. I could see how many bees "hatching" [coming out of their brood] would be hit with the Apivar and drop dead real quick. And we are presently having many bees eating their way out of the brood nest. Also, JRG showed me massive mites when we were cleaning up drone larvae that was all over the hive. If I remember correctly, some of the larvae had 3-5 mites in one capped larvae cell alone. So what you are saying makes a lot of sense.

Today we went back into this hive and split it several times. Two NUC's and one split, and one carry away. The reason we did this is because today when we opened the hive we found a substantial number of queen cells with the royal jelly, eggs, larvae, etc.

I suppose the hive was itching to split and hopefully we beat them to it.

JRG also brought over a few of those mite resistant queen cells, so we will see how this all works out!

Thanks again everyone for your time, advice, and patience with me.

I noticed not everyone agrees in every area...and that is good. We are learning from one another and that will keep us sharp, sharp, sharp!

Soar


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## soarwitheagles (May 23, 2015)

*Re: Wow! I am noticing a big difference between Apivar & OA vaporization results. W*



BernhardHeuvel said:


> Just shaking my head.
> 
> What kind of vaporizer did you use? Is it one of those self-made ones?
> 
> ...


Bernard,

Thanks for sharing. Wow, that vaporizer appears to be top of the line! I only had one healthy hive, so $650 for an OA vaporizer was kind of out of my reach at the moment.

I purchased my OA vaporizer on Ebay from The Czech Republic. I thought it was working well, but after reading your comments about some vaporizers only achieving 60% efficiency, I suppose I had best reconsider.

You stated that the Varrox showed a 90 % efficiency. Ok, I will start saving up my Euros and US Dollars for one. They are a bit expensive for me at $165!

Wow, 6-7 treatments at 3 days apart. This is a new schedule. I am wondering why so many people have different ideas on the vaporization scheduling. 

I hope to save up for a Varrox, then try your suggested schedule of 6-7 treatments, 3 days apart.

Thanks for sharing your insights!

Soar


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## mbc (Mar 22, 2014)

*Re: Wow! I am noticing a big difference between Apivar & OA vaporization results. W*

Maybe oxalic longevity in the hive is climate related, the dry newly condensed crystals are highly hydroscopic and will suck in moisture very quickly. I live in an area where there is high humidity for most of the year and the white powdery coating you see on everything immediately post vaporization disappears quite soon, I imagine in drier areas it will last longer.


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## grozzie2 (Jun 3, 2011)

*Re: Wow! I am noticing a big difference between Apivar & OA vaporization results. W*



BernhardHeuvel said:


> Just shaking my head.
> 
> What kind of vaporizer did you use? Is it one of those self-made ones?


I had a chance to hear Medhat Nasr (Alberta provincial apiarist, did some of the lab and field work for approving OA in Canada) talk on the subject at the British Columbia Honey Producers Association AGM a couple years ago. One thing he emphasized 3 times over, if you are going to use vaporizing, DO NOT go to the internet and just grab any half baked idea on how to make a vaporizer. The reason is simple. A well designed vaporizer will control the temperature in the basket and the OA will sublimate. BUT, if it gets to hot, then a chemical reaction occurs, and you end up with water vapour, which is about as effective in controlling mites as spritzing the bees with sugar water.

I had a chance to talk to him one on one later, and asked about this, asked specifically about a couple of the commercially available single shot vaporizers, one manufactured not far from here (in Victoria BC) and one from Europe. He said both of those will work well, if you follow the directions exactly. Again he emphasized to me, just be careful that you are not overheating and burning the OA, because that will just end up putting water vapor into the hives.

We bought the heilyser unit last fall, and I took a very close look at how it's made before we used it. The heating element does not come into contact with the OA at all. The OA is placed into a small basket which is machined and acts as a heat sink. There is another chunk of heat sink metal wrapped around the heater. When we did our first trials, I found that if we let it heat up enough to start sublimating, then unplug the power, there is enough heat stored in the metal of the basket and heat sink to finish the job for that round. We also found a substantial difference between the first load, when the unit started cold, and the second one, when the unit was already warm at the start.

I am expecting OA vaporization to get a lot of mixed reviews over the next year or two here on Beesource, and if we track the details, we'll find that a lot of folks using home built vaporizers are getting poor results, and those using units that are well thought out, following the directions exactly, will be reporting very good results. And eventually the subject will turn into another one of those semi-religious wars with one faction saying it works well, and another faction saying it's ineffective. Some will connect the dots as to why, and some will refuse to admit the real reason why they are not having success with vaporization for mite control.

I dont remember the exact numbers, but, I do remember that the delta between temperature required for good sublimation, and that which will burn the OA and end up with water vapours was comparatively small, it was something like 50C degrees between the two numbers, so careful control to not overheat the OA is important, and the difference between success and failure for managing mites with OA vaporization.


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## indypartridge (Nov 18, 2004)

*Re: Wow! I am noticing a big difference between Apivar & OA vaporization results. W*



grozzie2 said:


> I don't remember the exact numbers, but, I do remember that the delta between temperature required for good sublimation, and that which will burn the OA and end up with water vapours was comparatively small, it was something like 50C degrees between the two numbers, so careful control to not overheat the OA is important, and the difference between success and failure for managing mites with OA vaporization.


Exactly.
Sublimation starts at about 315F, and around 372F it decomposes and burns off as formic and carbon monoxide, so it's critical to maintain the temperature within the range, for a long enough time for it to complete sublimate.


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## Dan the bee guy (Jun 18, 2015)

*Re: Wow! I am noticing a big difference between Apivar & OA vaporization results. W*

Good information now I ordered one from brushy mountain how can we be sure it doesn't over heat?


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## snl (Nov 20, 2009)

*Re: Wow! I am noticing a big difference between Apivar & OA vaporization results. W*



Dan the bee guy said:


> Good information now I ordered one from brushy mountain how can we be sure it doesn't over heat?


I think Brushy Only sells the Varrocleaner. It's a good vap. Varrox is the cadillac of vaporizers..........


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## popejohnpaul2 (Apr 2, 2015)

*Re: Wow! I am noticing a big difference between Apivar & OA vaporization results. W*



Dan the bee guy said:


> Good information now I ordered one from brushy mountain how can we be sure it doesn't over heat?


See if someone you know has a thermometer gun, give it a test


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## missybee (Sep 6, 2014)

*Re: Wow! I am noticing a big difference between Apivar & OA vaporization results. W*

Varrox, I have used it since last year. It works great well worth the extra bucks. Bought it from SNL


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## BadBeeKeeper (Jan 24, 2015)

*Re: Wow! I am noticing a big difference between Apivar & OA vaporization results. W*



indypartridge said:


> Exactly.
> Sublimation starts at about 315F, and around 372F it decomposes and burns off as formic and carbon monoxide, so it's critical to maintain the temperature within the range, for a long enough time for it to complete sublimate.


Sounds like a temp sensor with feedback to a control circuit would be a good idea...


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## Dan the bee guy (Jun 18, 2015)

*Re: Wow! I am noticing a big difference between Apivar & OA vaporization results. W*



BadBeeKeeper said:


> Sounds like a temp sensor with feedback to a control circuit would be a good idea...


The one that dannpurvis used in his video had one or something like that.


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## indypartridge (Nov 18, 2004)

*Re: Wow! I am noticing a big difference between Apivar & OA vaporization results. W*



BadBeeKeeper said:


> Sounds like a temp sensor with feedback to a control circuit would be a good idea...


The vaporizer I bought is a bit pricier than others, but I like the digit temp readout and control logic:
http://myhoosiervillebeekeeping.webs.com/oxalic-acid-vaporizer


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## LeonardS (Mar 13, 2012)

*Re: Wow! I am noticing a big difference between Apivar & OA vaporization results. W*



indypartridge said:


> The vaporizer I bought is a bit pricier than others, but I like the digit temp readout and control logic:
> http://myhoosiervillebeekeeping.webs.com/oxalic-acid-vaporizer


They say it can be used with honey supers on, and also in freezing temperatures. That's the first place I've seen those comments for OAV.


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## snl (Nov 20, 2009)

*Re: Wow! I am noticing a big difference between Apivar & OA vaporization results. W*



LeonardS said:


> They say it can be used with honey supers on, and also in freezing temperatures. That's the first place I've seen those comments for OAV.


No, the EPA states you cannot use OAV with the supers on and you cannot vaporize below 37 degrees...


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## Mike Gillmore (Feb 25, 2006)

*Re: Wow! I am noticing a big difference between Apivar & OA vaporization results. W*



LeonardS said:


> They say it can be used with honey supers on, and also in freezing temperatures. That's the first place I've seen those comments for OAV.



There are very good reasons that recommendations are given to not use OAV with supers on, or with temperatures in the 30's. I think it's irresponsible to advertise these things. Raises a large red flag for me, and demonstrates a lack of understanding of the product they are listing. What else don't they know about it?


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## enjambres (Jun 30, 2013)

*Re: Wow! I am noticing a big difference between Apivar & OA vaporization results. W*

They also said to use * two grams or 1/2 tsp OAV* per brood chamber (deep hive body). They_ probably_ were assuming you always have a double deep as a brood chamber, but lots of beekeepers use a single one, in which case that would be a 100% overdose. 

The honey supers in place thing is also dead wrong, according to everything I've read.

To find a place to give them credit, though, they did remind people to don protective equipment beforehand, but they didn't say what that ought to be - sunscreen, maybe? //snark

Interesting thought to use a digital temp gizmo to watch the Varrox do its thing through a test heating cycle - has anybody done that already? I would particularly be interested in tests done at minimum air temps.

Enj.


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## Robbin (May 26, 2013)

*Re: Wow! I am noticing a big difference between Apivar & OA vaporization results. W*

I've used 4 different vaporizers. At the height of mite season, at the start of the dearth when my hives are booming and my supers have come off, I get THOUSANDS of dropped mites by the third day with the first treatment. If you aren't getting that kind of kill from OAV, you either don't have a big mite problem, or you're doing something wrong. OAV is VERY effective.


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## camero7 (Sep 21, 2009)

*Re: Wow! I am noticing a big difference between Apivar & OA vaporization results. W*



snl said:


> No, the EPA states you cannot use OAV with the supers on and you cannot vaporize below 37 degrees...


I just read the EPA sheet on OA. No where could i see where it says not to use it under 37°. 
https://www3.epa.gov/pesticides/chem_search/ppls/091266-00001-20151013.pdf


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## grozzie2 (Jun 3, 2011)

*Re: Wow! I am noticing a big difference between Apivar & OA vaporization results. W*



BadBeeKeeper said:


> Sounds like a temp sensor with feedback to a control circuit would be a good idea...


Scroll down on this page to the second unit displayed, the small OA blower.

http://www.members.shaw.ca/orioleln/vaporizer.html

This one was first pointed out to me about 2 weeks ago, and has since 'sold out', I'm sure Heinz will have more before long. Heilyser is down the road from us here on Vancouver Island, and I think the next time I'm down to Victoria I'll stop by and grab one of these units. It sure seems to hit all the bullets nicely for doing a treatment rather quickly. Temp controlled and can do 4 hives in one load. With that setup I can go down a line of 20 colonies and do an OA treatment in just a few minutes.


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## camero7 (Sep 21, 2009)

*Re: Wow! I am noticing a big difference between Apivar & OA vaporization results. W*

It certainly fits the niche between the vm vap and the single vap. I'm waiting for some actual use of this before buying. Saw a video of it blowing smoke but not being put to use on hives.


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## grozzie2 (Jun 3, 2011)

*Re: Wow! I am noticing a big difference between Apivar & OA vaporization results. W*



camero7 said:


> I'm waiting for some actual use of this before buying.


I have the JB200 single use unit which we used this winter, but I can see it becoming a time issue as we grow our colony counts. I fired a note off this morning to get on the list for the next batch he makes. For me it looks like the ideal setup if it works as advertised. Temp controlled, and I can power it by hooking up to the lawn tractor battery, which is how I do it with the single shot gadget. If I can do the whole works out back in less than an hour, it's worth the price IMHO.

Guess I'll have to get the wife to take a video of me using it after we get the thing, and post it where folks can see the unit in action.


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## camero7 (Sep 21, 2009)

*Re: Wow! I am noticing a big difference between Apivar & OA vaporization results. W*

Please do like Jean-marc and post your counts after using it. Also some idea of how effective it is to use would be helpful. I'm too small to consider the vmvaporizer and this might be just the ticket for a smaller operator like me.


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## shinbone (Jul 5, 2011)

*Re: Wow! I am noticing a big difference between Apivar & OA vaporization results. W*



Robbin said:


> . . . I get THOUSANDS of dropped mites by the third day with the first treatment. If you aren't getting that kind of kill from OAV, you either don't have a big mite problem, or you're doing something wrong. OAV is VERY effective.


This! (although 100's of dropped mites might be more typical)

There is no doubt that OAV is highly effective in killing mites. If a beek isn't seeing a large mite drop after OAV'ing, either he doesn't have mites, or there is something wrong with his treatment procedure/equipment.


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## mbc (Mar 22, 2014)

*Re: Wow! I am noticing a big difference between Apivar & OA vaporization results. W*



BernhardHeuvel said:


> In studies it was found that the half life of oxalic acid (dribbled though) in a hive is two weeks. So in a month it should be all gone. Problem is, the sublimated oxalic acid binds quickly to all humidity, be it in the air, on the comb or at the mite's feet. So what you get is droplets of oxalic acid anywhere in the hive. I don't think the mites will walk into a drop of oxalic acid, but rather avoids it. One of the behaviour is, to descend down into a broodcell about to be capped to escape the tricky situation. Bottom line is for me at least, OAV is effective only for minutes. There is no longterm effect.


This comment has been playing on my mind, it has important implications when considering treatment windows for snapshot treatments like oav, also it may explain partial efficiency with thymol treatments. 
Surely a varroa diving into cell prematurely will have reduced breeding success compared to ones who follow the usual progression, otherwise they'd all do it, no?


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## AHudd (Mar 5, 2015)

*Re: Wow! I am noticing a big difference between Apivar & OA vaporization results. W*

I don't believe a mite has to step on the OA. I believe the vapor must be contacting the mites feet as it crystallizes, otherwise, how would it kill a mite while it is piggy backing on a bee?

Alex


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## shinbone (Jul 5, 2011)

*Re: Wow! I am noticing a big difference between Apivar & OA vaporization results. W*



AHudd said:


> I don't believe a mite has to step on the OA. I believe the vapor must be contacting the mites feet as it crystallizes, _otherwise, how would it kill a mite while it is piggy backing on a bee?_


 (my emphasis)


Below is a photo of a bee coated with oxalic crystals:












(from Wikipedia https://en.wikipedia.org/wiki/Oxalic_acid )


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## AHudd (Mar 5, 2015)

*Re: Wow! I am noticing a big difference between Apivar & OA vaporization results. W*

From the looks of that it would be hard for a mite to not get any on its feet. Thanks for the pic.

Alex


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