# Oxalic acid dribble didn't work. What went wrong? Can I treat again?



## bluegrass (Aug 30, 2006)

I see a couple of problems.

1. Your measurements need to be precise and should be by weight. Mix your 1.1 syrup and measure out 1 L. Add 35g of OA crystals. 1.5 oz of OA should be about 28g so in two quarts you are way under strength. Get a good kitchen scale and measure it out to 35 g.

2. OA dribbles only work on clusters of bees, if you are doing inspections I surmise your bees are not clustered for the winter yet. In that case it is too early for OA dibble in your area. Also your hives need to be as close to bloodless as possible when you treat. 

The hot water is not an issue; your main issue is that you mixed it too weak.


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## bluegrass (Aug 30, 2006)

This is what a mite drop will look like, providing they really need to be treated.


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## jim lyon (Feb 19, 2006)

Ben: I had warned against using hot water to mix up oa but only because a whiff of the steam the hot water puts off can be pretty nasty. My guess is that it is a bit too early there for your bees to be broodless. In our area a September treatment needs to needs to give you at least one week of effectiveness. OA will only be effective for a few days at the most.


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## Rader Sidetrack (Nov 30, 2011)

> I mixed up a couple quarts, using 1:1 syrup to 1.4-1.5oz of OA crystals. 

If you mean 1.4 oz of OA with 2 quarts of 1:1 syrup, then _Bluegrass _is correct about your mix being too weak.

When you asked earlier, I though we were talking about 32 oz of syrup, here:
http://www.beesource.com/forums/sho...perienced-please-check!&p=1003792#post1003792

Also, your comment about _hot _water, and earlier asking about shelf life of the mix, suggest that you may not have read/absorbed Randy's page on OA dribble, even though you are apparently using his mix ratios.
http://scientificbeekeeping.com/oxalic-acid-questions-answers-and-more-questions-part-1-of-2-parts/
Both of those issues are covered by Randy.


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## sjj (Jan 2, 2007)

westernbeekeeper said:


> So, I got to the point where ... !


Veterinary physician would not call it a treatment if the efficacy were not 99%. 
Anecdotal reports suggest that a degassed coca-cola drench could do the same as your OA method.


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## westernbeekeeper (May 2, 2012)

I have a very nice postal scale which I used in weighing the OA. I mixed exactly 1.47 oz of OA to a precise quart of 1:1 syrup. But whatever the problem, it didn't work. I read there several places where I may have gone wrong; sorry, its my first time using OA.  So, the question is: Can I treat again? either with OA, formic acid, Hopguard, apivar, or other? Not sure my bees will survive with the mite load I have. They are very strong hives, with excellent brood patterns and great stores.


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## jim lyon (Feb 19, 2006)

westernbeekeeper said:


> So, the question is: Can I treat again? either with OA, formic acid, Hopguard, apivar, or other? Not sure my bees will survive with the mite load I have. They are very strong hives, with excellent brood patterns and great stores.


Sure, though I wouldn't use OA again at this point given the amount of brood still in your hives and the fact that consecutive applications can be pretty stressful on particularly smaller hives.. Apivar is probably going to do about the best job if you feel like using Amitraz in your hives. The other products are stressful to the bees to varying degrees and are all pretty temperature dependent. We are currently still treating with thymol strips.


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## JWChesnut (Jul 31, 2013)

Likely the best controlled and accessible report on OA dribble is the thesis by Nicolas Aliano
http://digitalcommons.unl.edu/cgi/viewcontent.cgi?article=1000&context=entomologydiss
and the article he published on one aspect of his thesis work.
http://digitalcommons.unl.edu/cgi/viewcontent.cgi?article=1186&context=entomologyfacpub

Some points: when brood is present Aliano found a slight, but ultimately insignificant effect of OA dribble. (His protocol was weekly applications for three weeks). He did not detect cumulative toxicity, but he also didn't observe control of VM.

He was able to reproduce very effective Varroa control using dribble and/or spray on **broodless** fall colonies, and experimental "packages" of shook bees.

A key finding of Aliano is illustrated by this figure from his publication (modified by JWC).


OA:Sugar solution is toxic to mites, **and** toxic to bees. Control requires an effective toxic dose on the mites, while under-treating the bees.

Industry sources describe using a 3.5% solution dosing at a rate of 50 ml per 10 frame box, this is metered to 5 ml per frame gap to distribute the solution evenly. The Aliano figure shows that 5 ml (of 2.8%) has a highly effective impact on mites, but only lightly affects the bees. He calculated impacts at a "per 1000 bees" value. His experimental subjects were shook packages of 1,600 bees each. 

In order to extrapolate in hive loadings, a realistic estimate of bees per hive is needed. The drawings on the Cushman memorial page are the best resource I know of: http://www.dave-cushman.net/bee/beesest.html My own estimates based on photo's of my frames and sub-sample counting is a frame with "top cover" -- or bees crawling over the top bar -- has 1600-2000 bees per frame (2 sides counted). I don't have good estimates for cluster size counting. One can estimate hive population by counting top cover frames x 2000 (dispersed bees ignored). One can further estimate loading needed in a **broodless** dribble or spray by top cover/2 * 5 ml. This yields a max of 25 ml per deep, which is half the volume typically applied. Aliano used a painting airbrush with a pigment cup, and "airbrushed" his packages evenly. Perhaps his lower loadings illustrate at least half the hive dribble is immediately wasted. The industry practice of 50 ml per deep is likely within (but near) the practical limit reported by Aliano to avoid direct bee mortality.

As an aside, the mode of OA is poorly understood. OA is a simple 2 carbon chain -- 








when placed in solution (sugar, moisture, and injested with a H20 source) it immediately sheds H+ protons to become a conjugate base--








The base is termed Oxalate -- and its reaction potential is such that this transformation is rapid and complete. It is a massive H+ donor and as a highly reactive anion-- forms compounds with 2 valance metals such as Ca++

If the key mode of action is a rapid acidification of the Varroa hemolymph through absorbtion directly or injestion from the bee brood -- then consider that the those who promote ascorbic acid additions to feed solutions (and/or) highly acid honey development might be using analogues the OA effect. The impact of H+ in 5 liters of "acidified syrup" and 50 ml of OA might be similar, as OA is a 1000 times stronger acid (H+ donor) than ascorbic or acetic acid.

My irony meter pegs when I consider that "acidified syrup" advocates (scornful of treatment) and OA devotees (frustrated with TF zombies) are simply using the same acid impact treatment, with different donors -- OA is a simple natural acid, and ascorbic -- a more complex carbon ring.

Within a moist hive, OA will form Calcium Oxalate crystals (and similar insoluble salts). These crystals are very sharp, and might present a mechanical danger to the mites.


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## JWChesnut (Jul 31, 2013)

To respond to your direct question, Randy Oliver reprints this advice from the developer of the Heilyser vaporizer.
http://scientificbeekeeping.com/oxalic-acid-questions-answers-and-more-questions-part-1-of-2-parts/

Heinz Kaemmerer of Heilyser Technology says:

“You can treat your colonies with a liquid mixture of OA and sugar but be careful. The liquid acid shortens the life of the bees. There is no problem during summer because the bee’s life not longer than approximately 6 weeks. The problem starts with winter bees–do not treat your winter bees more than one time with liquid OA. When using liquid OA bees get wet and have to clean each other. The result is, the acid ends up in their stomach and during winter without a cleaning flight it shortens the life of the bees. Two treatments on winter bees might kill the colony. Liquid OA is a slow killer and bees will probably die after a few weeks or month instead reaching the next season.”


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## Rusty Hills Farm (Mar 24, 2010)

I have been scratching my head over the OP ever since I read it. How could it not work?!?

Well, I'm a hands-on type so...I went out to my kitchen and made up a batch. Using the formula Rader helped me work out a couple of days ago, I had to actually mix the whole thing before I finally understood what happened.

The formula we had worked out on that thread was:
1.2 oz OA
16 oz. water
16 oz. sugar

Now at first glance that's a quart of solution, right? Except it isn't. It actually makes about 24 oz. of solution, not 32! I think THAT is where westernbeekeper's problem lies and why his treatment didn't work.

When you add sugar to water--16 oz to 16 oz, in this case--you don't get the final amount you might expect to get. It's something about how the 2 combine, so instead of 32 oz you get 24. So when westernbeekeeper started off with 32 oz of 1:1, he needed more OA than he used. Just don't ask me how much more--lolol--my math just isn't up to it!

Now I feel bad for westernbeekeeper. I feel like our discussions contributed to his confusion instead of helping him with it! So, Benjamin, please accept my apologies!

Rusty


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## JWChesnut (Jul 31, 2013)

Quick and dirty recipe for 3.5% OA in 1:1 syrup

A level tablespoon of Oxalic dihydrate wood bleach crystals is 12 g. The weight is very consistent if you use a knife or playing card to level the Tablespoon measure. 3 level tablespoons == 36 g 

A liter of 1:1 syrup weighs 1240 g. 1:1 syrup is often prepared on a volume to volume basis (as sugar and water are close enough in bulk density). 
A kilogram of 1:1 syrup is almost exactly 800 ml. Kitchen 2 cup measures have ml markings, so use these or 3 1/4 cups as a rough alternative.

Make the syrup with 4 cups of warm water and 4 cups of white sugar, yields about 24 fluid ounces - you'll have extra syrup.

Add 3 level tablespoons to 3 1/4 cups of syrup mix, makes sufficient volume to treat 16 hives.

The syrup is strictly to raise the viscosity of the solution, so it doesn't run off the bees hairs as quickly, and dries in place. If you make the solution less sweet than feed or honey you reduce the likelihood of the bees injesting it -- injestion is uncertain in effect.


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