# OA effectiveness



## BWrangler (Aug 14, 2002)

Hi Ox,

The treatment is working when thousands of mites drop after a treatment. If it wasn't, very few mites would drop.

OA is the most benign treatment I've found for mites. It won't hurt to continue the weekly treatments. That's what I would do.

I think you are experiencing the rapid mite build up that Michael and I have talked about. When monitoring natural mite fall, I've had hives that consistently drop less than a dozen mites per 24 hours suddenly drop 300+ mites per day for a week or more. Then they would return to a dozen or less mites per day. The rates are dependant on several convergant factors and are not as constant as most believe. And they can change dramatically when mite levels are very high toward the end of the season.

I have also looked at the graph you referenced and am sure something is lost in translation. The vertical axis refers to a percent effectiveness which doesn't directly correspond to changes in the rate of infection. At very low levels of infestation, it might be hard to detect a upturn in the rate of infestation. I think they just measured percent of infestation and didn't see an increase for the 44 days.

When I regressed my regressed bees, that is put some small cell bees back on large cell comb, they developed the situation you see in your bees in one season. I started weekly OA treatments on them about mid to late August, when I saw the first crawlers. After three or four treatment all crawlers were eliminated and the hives survived the winter with little apparent damage the following spring.

I have found OA treatments to be robust and effective. If you get it in the hive, it will work. But it's not an instant cure. Even the strips require a brood cycle to a cycle and a half to work just like the oxalic.

Monitoring mite counts can produce the uncertainty you are experience. With strips, they are usually just put in a hive for the proper time and forgotten. No monitoring. No mite counts. Just pop, pop. Fizz, fizz. Oh what a relief it is. Or so it seems. But if mites were actually being monitored when using the strips, the same kinds of variations would be seen.

If you continue your treatments, let us know how the mite counts progress.

Regards
Dennis

[This message has been edited by topbarguy (edited October 30, 2004).]


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## ox (May 15, 2004)

Thanks so much for your reply. I had a gut feeling that was the scenario playing out but needed to check with the experts. I fully intend to continue with the treatments until some kind of stability is reached and I will post the results here.
I'm not looking for instant cures. Just gentle effective ones. My concern was that perhaps I had erred somehow. To have a really low mite count all season and then have pandemonium break out was bad enough. Then to have apparent progress in the mite count only to see even worse mite counts after a full month of treatment unsettled me. The fact that crippled bees are still evident seemed to indicate brood still hatching and that perhaps I had not seen the peak of the infestation fully exposed. Hopefully this mornings enormous shed of the miserable beasties is the worst of it. The bees are very active in cleaning the sick bees and pupae out. The weather is really starting to get cold, wet and fly time for the bees is much shortened. The hive population seems strong. 
I know of hives in this area that are infected with mites so I assume the battle will be on going. Just start the treatments in July you think?

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the ~ox-{ at www.singingfalls.com 
If this message is edited it is because I have to correct my spelling again. 0_0


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## honeylocust (May 11, 2004)

Ox, my experience with the mite situation and using OA has been similar to yours.

I've done three treatments of OA on two hives. #1 hive was badly infested and about ready to crash and #2 hive was very robust with very few mites. 

After the OA treatment the mite drop was constant on #1 hive, which was confusing. I expected the mite drop to increase dramatically after the OA use since this hive was so badly infested. I later discovered that all the brood had died so that explained why the drop didn't increase after the OA use. (No more mites reproducing in the cells.) After the 3rd treatment the mite drop is down considerably but not as low as I would like. It's still in the 20-80 /24hr range and the hive population has been dwindling. The queen has now started to lay again and the bees are now cleaning out the dead cells. So, they are feeling much better, thanks to the OA.

#2 hive dropped mites in the hundreds after the 1st treatment and in the thousands after the 2nd treatment. This was very surprising since the mites were in the 6-7 /24hr count at the end of August. After the 3rd treatment the drop is anywhere between 125-217 /24hr which is still too high for me to be comfortable with. 

It has been two weeks since the last treatment of OA. I do believe that the OA is working and my bees are feeling better but that the three treatments were not enough. I've decided to continue with weekly treatments until the mite drop gets lower. 

With what I've read it sounds like OA is fairly benign to the bees. So, hopefully it will be better for the bees to continue the treatment until the mite population gets lower.

Good luck with your hives.


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## dickm (May 19, 2002)

I'm in the same boat. After 2 treatments I am dropping too many mites to count.(Counts were 20 to 150 a day before I started) 2 hives had 3 tx in early Aug. (Of 18) I KNOW that O/A is killing mites because of the drops after tx. Axtmann says it keeps killing for weeks because of the residue on the hive parts. That may explain high counts a week after tx. I'm also waiting for no brood to treat for a last time. I feel more confident about wintering than I've felt in a long time.

dickm


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## ox (May 15, 2004)

I must admit that yesterday mornings mite count was a most miserable sight. I would have wasted half the morning counting mites there were so many. What a plague! The bees themselves look in very good condition and seem like young ones (not many frayed winged older bees). 
Question: What effect does the acid have on brood in open cells? And though I have seen one small article on the effect of the acid on the mites, I really don't know how this stuff works or why it doesn't hurt the bees also. Any URL's for me to go read?

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the ~ox-{ at www.singingfalls.com 
If this message is edited it is because I have to correct my spelling again. 0_0


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## BULLSEYE BILL (Oct 2, 2002)

>What effect does the acid have on brood in open cells?

I believe it has been suggested here that the larva is protected by being coated with royal jelly. Once it is large enough to be exposed it is large enough that the caustic effect of the vapor is not a problem.


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## ox (May 15, 2004)

Thanks!
Mite count yesterday morning was way up again (several hundreds at least). 
The one thing I did differently in the last treatment may have influenced the effectiveness of the vapors. I added an empty deep to the top of the hive so I could top feed syrup. They really don't need it but I didn't think it would hurt. The portal for my vaporizer is in the upper left back corner of the upper hive body. After treatment I noticed that naturally, the vapors filled the new empty deep also. Perhaps this made the distribustion of the vapors more even througout the hive







What ever the case. I am glad to see the little terros dropping! I thought of building a 2 inch high frame with a glass top for doing the vapor treatment just so I can see what is going on.

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the ~ox-{ at www.singingfalls.com 
If this message is edited it is because I have to correct my spelling again. 0_0


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## BULLSEYE BILL (Oct 2, 2002)

>I thought of building a 2 inch high frame with a glass top for doing the vapor treatment just so I can see what is going on.

Funny that you should mention it. I have here two such items that I have been meaning to put in the for sale section as soon as I take a picture and post it in my web site for viewing. I'll try to do it tonight.


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## BULLSEYE BILL (Oct 2, 2002)

Look in the For Sale section for an Oxalic hive top plexiglas vaporizer box with crack pipe.
http://members.cox.net/bullseyebees/_sgt/m2m2_1.htm


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## ox (May 15, 2004)

That's exactly the design I had in mind. I hope to wip one up in a couple of days for the next treatment. Did you use plexiglass? 

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the ~ox-{ at www.singingfalls.com 
If this message is edited it is because I have to correct my spelling again. 0_0


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## BULLSEYE BILL (Oct 2, 2002)

>Did you use plexiglass? 

Yes, and got a good case of sticker shock when I went to buy it too. As always, I glue and screw everything, even the plexiglas. If I was to make another I think I would use heavy glass and use a weather strip on the bottom to help make a better seal.

I would also recomend that if you are going to top vapor you should use at least 3 gm (teaspoon full) to be sure to fill the entire hive with vapor. Since you need to 'push' it down a little extra is needed.

[This message has been edited by BULLSEYE BILL (edited November 02, 2004).]


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## Beemaninsa (Jun 9, 2004)

Thankyou all for contributing to this topic. I have been following with great interest. I am excite to see if the frame and crack pipe works well. Do you leave the setup on the hive for 10 min or can you remove, replace lid and go to next hive? How many hives per hour would you estimate you can work with one frame and crack pipe? Some of my hives have a narrow entrance. I was considering a similar "frame and electric vaporizer". Do you think that would work? The only reason I was thinking about an electric vaporizer is that assume you have a faster reload time and less chance of overheating the acid. Thanks again.


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## Dave W (Aug 3, 2002)

Greetings . . .

I made the "same" glass-topped frame using a sheet of Lexan from Lowes.

Try this!!!

Place the frame on a pc of (dark) cardboard, heat charged pipe, Time and watch for white fog (will tell you how long to heat for total fumigation).

Wait 10-15 minutes, and examine cardboard for OA residue. I did, and this thing works GREAT. Its neat to watch the bees fan this stuff in hive, too.

Sure hope its only killing mites


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## Dave W (Aug 3, 2002)

BULLSEYE BILL . . .

For the NewBEEs, are you suggesting to use 3 gm ("level" teaspoon?) in a single-, double- or triple-deep hive?


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## BULLSEYE BILL (Oct 2, 2002)

>are you suggesting to use 3 gm ("level" teaspoon?) in a single-, double- or triple-deep hive? 

I shouldn't assume anything, but I guess I did. We use double deeps or three mediums in this area and that is what I was basing that upon.

One gram per deep box is the recomended dosage for bottom vaporizing. I would use a bit more in the top vaporizer as it is having to vent down to reach the brood area and the gas is naturaly trying to rise.

A heaping half teaspoon is two grams, a level teaspoon is about three grams.


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## ox (May 15, 2004)

mite count is way down again and there are few newly hatched deformed bees at this point. I may have reached the downhill side of this plague. Next treatment is today. I'll keep you posted.

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the ~ox-{ at www.singingfalls.com 
If this message is edited it is because I have to correct my spelling again. 0_0


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## ox (May 15, 2004)

30 mites. I noticed no deformed bees today.
It was sad to see the deformed winged bees fanning the entrance after treatment yesterday. Usually I see them either crawling away or being carried away. I'm getting to be a softy in my old age









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the ~ox-{ at www.singingfalls.com 
If this message is edited it is because I have to correct my spelling again. 0_0


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## BWrangler (Aug 14, 2002)

Hi Guys,

I'm posting a link from Allen Dick's diary page with some research info concerning oxalic. The Canadians are perfecting and will soon register oxalic as a mite treatment. I think Allen has been instrumental in this effort and I bet the Canadians will help refine the technique for maximum effectiveness.
http://www.apis.admin.ch/en/krankheiten/docs/saeuren/osverdampfen_e.pdf 

I haven't seen much difference in the effectiveness between application points. But I haven't used used my evaporator when the bees are clustered inside the hive. The mites are most vulnerable at that time. 

Getting oxalic inside a tight cluster might be harder than it appears. I wonder just how much oxalic would make it through a cold bottom box and into the middle box where most of my bees cluster. I winter in three deeps. I think most of it would condense in the lower box before reaching the bees. 

Yet, I still prefer an earlier treatment. Lots of young, healthy bees can develop before winter. And the bees can fly, get water, etc. to mitigate any negative impact the oxalic might have.

Regards
Dennis


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## BULLSEYE BILL (Oct 2, 2002)

Thanks TBG! Sounds like verification of what Axtman has been saying about the electric vaporizors. Something that I have been missing is the placement DIRECTLY under the brood nest. I will have to be more careful to measure how far I insert the vaporizor into the hive from now on. Thanks again.

>Conclusions
A high treatment success of oxalic acid electric evaporators is possible, if the devices are placed correctly in the bee hive, i.e. if they are inserted underneath the winter bee cluster. This is recommended in the directions for use of the devices. Both gas evaporators using only the thermal effect for the transport of sublimated oxalic acid showed insufficient efficacy. This problem can be solved with the help of a small ventilator blowing the sublimated oxalic acid into the beehive. This investigation shows clearly the importance of testing the efficacy and possible side effects of new, interesting ideas from the practice. This is the only way to avoid bad surprises.


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## Axtmann (Dec 29, 2002)

When I go directly under the cluster or under the brood nest I often have a roasted bee in the acid tray. But I find out that the electric is much more effective than all the other available ore home made vaporizers. 
I think it is not worth to play around and try to save some money; the result is what counts in the long run.
On the link, all the propane heated are less effective than the electric, even when they put a fan on it to blow the acid inside. 

Why should I use propane and electricity when I have the best result with electricity only?


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## ox (May 15, 2004)

The beauty is in the success! Fortunately my bees are not clustered yet and lots of young healthy bees are flying in front of the hive when the day warms up. Good time to treat! We had a very hard frost this morning (first seriously cold morning of the year so far. My wife wisely harvested the rest of the ripe and also green tomatoes along with the hot peppers yesterday.

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the ~ox-{ at www.singingfalls.com 
If this message is edited it is because I have to correct my spelling again. 0_0


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## Axtmann (Dec 29, 2002)

Ox after killing thousands of mites you sound much better now.


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## ox (May 15, 2004)

Indeed Axtmann! It is very encouraging to see a plague subside AND actually have a reasonable solution to the problem - thanks to you and the folks here on the board. It means a lot to me and pray the Lord blesses you all for it. 
I'm sure you would know. How was the use of Oxalic Acid first discovered and by whom?

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the ~ox-{ at www.singingfalls.com 
If this message is edited it is because I have to correct my spelling again. 0_0


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## Axtmann (Dec 29, 2002)

As far as I know, several scientists and beekeepers claim to be the discoverer and developer of OA treatments against Varroa mites.

Tests are made since 1989 at the apiculture Fischermühle and they published 1994 the first spray methods. But during this time Dr. Wolfgang Ritter and Dr. Liebig also published the first positive results.

I personal know a Russian immigrant who started with liquid OA treatments in Russia during 1982.

I think, all European scientist first started with chemicals like Apistran or Perizin (chumafos) from Bayer, but the beekeeper in the eastern part of Europe, behind the iron curtain couldnt pay for that and find a different way, many thanks to them.


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## dickm (May 19, 2002)

Hi Ox, Axtmann,
I want to second the thanks for O/A.
Here in CT (USA) I'm about to go into the last treatment. (I'm wondering if I made a mistake doing it 10 days apart instead of 1 wk.) Anyway, I presume the brood is at a minimum and I'll be doing it once more. It certainly is a conflicting emotion to see all these mites fall after a tx. Then I remember they are DEAD. I have some confidence going into winter. Then it's back to scraping and building equipment.

dickm


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## BWrangler (Aug 14, 2002)

Hi Guys,

I know the Eastern European beekeepers were fuming hives with amitraz, etc. before using acids. They would burn cords soaked in pesticides and also used some organic solvents as the carrier. I wonder if the softer treatments were developed in response to pesticide failures which usually show up about 10 years after treatments start?

It seems that the mites travel faster than the information on treatment histories and their failures do.

I wonder if there is any news from the east :> )

Regards
Dennis


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## ox (May 15, 2004)

Mite count is in the thirties that last few days. Far less than at the peak but still not what I'm looking for. Crazy bees are still finding pollen after 3 nights of hard killing frost







No doubt the OA is working.

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the ~ox-{ at www.singingfalls.com 
If this message is edited it is because I have to correct my spelling again. 0_0


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## TwT (Aug 5, 2004)

where do yall get the O/A from or are you useing something with a brand name ?


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## BULLSEYE BILL (Oct 2, 2002)

Go to Lowes or Ace hardware and get a small plastic tub of wood bleach. Here is a picture of it; http://members.cox.net/bullseyebees/_sgt/m2m2_1.htm 
click on the picture to enlarge and read the name.


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## ox (May 15, 2004)

Mite count is in the 20's. Definitately a downward trend.

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the ~ox-{ at www.singingfalls.com 
If this message is edited it is because I have to correct my spelling again. 0_0

[This message has been edited by ox (edited November 10, 2004).]


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## ox (May 15, 2004)

mite count *4* !!!

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the ~ox-{ at www.singingfalls.com 
If this message is edited it is because I have to correct my spelling again. 0_0


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