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I believe so. After all, they get coated with the stuff and groom it off.
 

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d) Oxalic acid was developed to the final-use stage as a drug in bees by the European Working Group for Integrated Varroa Control (CA 3686). In all EU countries, government approval is only given to a new veterinary medicament for use in treating animal diseases after the EMA, the European Union’s Agency for Evaluating Medical Products, has determined the maximum residue limit (MRL) of the active ingredient allowed in the final food product according to European legislation. This procedure is meant to protect consumers from toxicologically critical residues in foods resulting from medicines used on animals. For oxalic acid no MRL was available. The MRL establishing procedure was started in cooperation with A. Imdorf (Agroscope Liebefeld-Posieux, Swiss Bee Research Centre), J.M Poul (Agence Française de Sécurité Sanitaire des Aliments) and A. Wibbertmann (Fraunhofer Institute for Toxicology and Experimental Medicine), carried out as a joint project of many European countries and successfully finished in December 2003: oxalic acid was listed in Annex II of Council Regulation (EEC) 2377/90 (Rademacher and Imdorf , 2004). This means that the substance is evaluated as not dangerous, and no residue limit is needed to protect the consumer. On this basis every European country can apply for approval and the Concept of Integrated Varroa Control, as recommended by the scientific institutes for bee research, can legally be implemented. It was the first time that scientific institutes and beekeeper organisations worked together on a European level to establish the legal basis for drug approval in bees.
 

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Thanks, snl. I'm glad to know that the evaluation has been done.

Toxicology and industrial safety are complex areas, and once in a while numbers considered in isolation don't tell the whole story. The PEL that I mentioned above is one example. That PEL measurement assumes a constant exposure for 8 hours at the level specified, and in some cases is based on limited information. Many PEL levels were listed in the 1970's based on information available for similar possible substances, but without specific experiments having been conducted. It's good to know that a closer look was taken for oxalic acid in 2003, and that the information was updated based on real information.

Thanks again for updating us all on this. In my mind, this new (to me) information means that OA used according to label is not a hazard to human health.
 

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Hello Glenn,

Thanks for the information on the coffee cup heater and the cap for Varroa treatment. I'm wondering how long these elements last from your observations. Since the element is meant to immersed I'm wondering if you've had them fail on you after a certain period of time. Thank you.
 

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Remember to treat the hives in the fall after the supers are pulled just to be on the safe side, it has been said that Oxalic can be applied with the supers on but I just do not want to take that chance.
Hi Bill ― a few years down the road now from this post. Are you still using oxalic in this method and what kind of results are you seeing? Thanks. :)
 

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I built mine and 12 others the same as KY Mike. I use an Auto lite 1107 glow plug as found on eBay for about $9.00 You don't need to thread the glow plug into the aluminum. I turned the threads off (you could file them off) and used a setscrew to hold it in. I drilled the hole for the glow plug to fit as tight to the glow plug as possible(slip fit) to aid in the heat transfer. I found you may want to cover the lead to the glow plug (+) with shrink tube or electrical tape so it doesn't short out on a hive cover. We had a glow plug die when that happened.
I bought my Oxalic Acid on eBay and got enough to cover my local dealer and myself for a long time to come..LOL

Yes I'm a newbie here but I've have bees since I was 8, I have white hair now but not from bees.
Scooter
 

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Like the looks of it. I read modern glow plugs heat up to 1000 degrees, would a 350 thermostat in series with glow plug affect it greatly.
 

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I'm using a vaporizer similar to what glen made, and attached a coat hanger handle to get it to the middle of the hive. I timed mine with a stop watch in a trial run (stay downwind!) then used the same times inside the hive. It's important to have a bucket of water to cool the vaporiser so you get the same performance every time. I power mine off my lawn tractor with the engine running, so a partly discharged battery doesn't affect the temperature.
 

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Like the looks of it. I read modern glow plugs heat up to 1000 degrees, would a 350 thermostat in series with glow plug affect it greatly.
Why mess with something that works ? It's only on for 3 minutes or less. I've had excellent results with mine... no mites!

Scooter58
 

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This is an older thread, however, I may be able to add a bit of information. Two weeks ago I mixed oxalic acid with a food grade glycerin. I heated it up to about 180 degrees F and the O/A dissolved. I was about the same viscosity as mineral oil. I used an insect fogger (Amazon) and treated just 2 hives to see what affect it might have on the bees. Last Tuesday I checked the boxes and all seemed to be well. I used the same glycerin/OA, which kept just fine and did not settle out, to treat again yesterday and today all seems to be well in the hives. As soon as the drone population starts up I plan to pull out a few larva and see if they have a higher or lower mite count.

If this method of O/A treatment is effective I plan to use it on all my colonies including nucs and maybe mating nucs. I do not have the perfect ratio yet and if anyone tries this method I would appreciate some feed back of both ratio and effectiveness. If this system works out to be effective I will be a real time saver compared to the heated battery powered cup.

Again, thank you for tolerating me, LP
 

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This is an older thread, however, I may be able to add a bit of information. Two weeks ago I mixed oxalic acid with a food grade glycerin. I heated it up to about 180 degrees F and the O/A dissolved. I was about the same viscosity as mineral oil. I used an insect fogger (Amazon) and treated just 2 hives to see what affect it might have on the bees. Last Tuesday I checked the boxes and all seemed to be well. I used the same glycerin/OA, which kept just fine and did not settle out, to treat again yesterday and today all seems to be well in the hives. As soon as the drone population starts up I plan to pull out a few larva and see if they have a higher or lower mite count.

If this method of O/A treatment is effective I plan to use it on all my colonies including nucs and maybe mating nucs. I do not have the perfect ratio yet and if anyone tries this method I would appreciate some feed back of both ratio and effectiveness. If this system works out to be effective I will be a real time saver compared to the heated battery powered cup.

Again, thank you for tolerating me, LP
 

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dadux,

I do not do mite counts. I check the drones and from time to time when the weather permits, I sit and observe . I know this isn't the most scientific way, however, so far I think I can pretty well tell. This is the second year that I haven't had any winter losses, at least so far. It is pretty easy to extract a drone larva and examine them for mites. The mite really stands out on the white exoskeleton. I want to be really careful to just offer what works for me and not try to tell anyone else how they should raise their bees. Just because I think something or if something appears to work for me, that doesn't mean that I am right or that my ways are any better than anyone else's way. They may be much less effective.

I might have mentioned that "I snap my fingers to keep the elephants away", For the past 40 or 50 years this has worked %100 of the time. I also want to announce that "all the Indians in South America walk in a straight line, at least the one I saw did."

I wish you well, LP
 

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I measured out a loose filling of OA into a 1/2" copper cap. on a jewelers scale came out to 2 grams. I think alot depends on moisture content in addition to how firmly you pack it.
 

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Well I'm taking the plunge and am currently working on a DIY vaporizer. The heating element is a Autolite 1107 glo plug that has M10x1 threads on it. I'm using a 350 degrees high temperature cutoff switch and plan to wire in an indicator light which turns off once the acid has vaporized and the switch hits it's shut off temperature. Already have machined the heater block and reservoir and am working on the handle and wiring.I'll get some pictures posted.
 

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That is close to what I'm building but doesn't have the temperature shutoff I'm using. So far I'm into mine for about $45.00 but will have a good seven or eight hours in the build when done.
 
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