# OAV and Queen Loss



## Colobee (May 15, 2014)

An experiment with ~1/2 of my hives, using a Varrox, the recommended dose & application technique ( Fall, 3 times, ~6 days apart) yielded no queen losses. 

So the questions are - what kind of vaporizer, what dosage, & how was it administered & maybe _when_ ...

You say "6 treatments into this season", - what intervals, & beginning last fall, or spring... ? 

Why do you treat in the winter? There should be no need to. Mite counts should be almost zero then, especially if you are treating in the fall. 

As an aside, my "experiment" was inconclusive - no losses from either the treated OR untreated hives...


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## Brad Bee (Apr 15, 2013)

I used 1/4 tsp of Savogran OA per box on my first test treatments last spring. I have a Varrox vaporizer and followed directions. I treated 3 hives that were infested with mites. The bees were in poor shape but I did lose 2 out of 3 queens, on the first treatment. 

Maybe they were too far gone and died from that reason. Maybe not. I don't know. They were all 2015 queens so they weren't quite a year old. 

I did treatments on several nucs later in the summer, 3X over a 20 day period. I had no Queen loss in those. I did change from the Savogran acid to lab grade that's 99.8% pure. I figure anything lab grade is made under more regulated conditions than wood bleach is. 

I would like to hear more about Queen loss using OAV because when it happened to me, I felt like I was the only one in the world that it had ever happened to.


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

I would think you treated to late. Is it possible that the mites had a little feed time on your queens before you treated? One thing I took away from a YouTube video that had Randy Oliver was start with a low mite count in the spring and keep it low. I haven't had any problems useing OAV .


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## camero7 (Sep 21, 2009)

Never lost a queen to OAV


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## dudelt (Mar 18, 2013)

I have done 50-60 total treatments with OAV. I have never lost a queen to it.


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## johno (Dec 4, 2011)

I wonder how many beekeepers have just lost a queen, don't know why but there was a queen last time I checked but gone now. This has happened to me on a few occasions especially over the winter period. Forward now to using OAV every time one loses a queen is OAV to blame? I have lost a few after a round of OAV and have also felt nervous especially using a wand and seeing a fried bee in it that looks like it could be a queen. That's when I started looking for a way to get the OAV into the hive without placing a hot wand into it and so went on to a band heater type of vaporizer that had all the heat outside of the hive and the vapor going into the hive through a hole in the back, problem sorted out and hives vaporized in less than a minute each hive. Then also in one of Randy OLivers tests on hives he was worried about the amount of queen losses in his test hives and then found a greater number of losses in his control hives. Make you think does it not.
Johno


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## crofter (May 5, 2011)

That is my motivation as well (the ability to quickly treat without pushing anything into the hive bottom. Have not had the queen loss close enough to treatments with OA to feel that was an issue. Oxalic acid has been my only mite treatment in three years at least with no losses. That is only averaging a bit over 6 colonies.


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## BernhardHeuvel (Mar 13, 2013)

Never had a single case of queen loss by oxalic acid vaporizing.


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## jvalentour (Sep 4, 2014)

johno,
I have switched to the same type of vaporizer. Hope to use it soon.
It quite probably is the heating element in the interior of the hive. Would a battery size (deep cycle boat battery) cause the element to heat up too much?
But I watched 2 queens, in different years leave the hive when I removed the towel at the entrance. Both times I caught them and put them back on the landing board only to watch them scurry off.
I did get a late start on the treatments this year so the thinking they may have been already in a weakened state has merit. Instead of starting in October, this year, I'll start shortly after I pull off the honey.


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## Yukon Bees (Dec 29, 2014)

I've never had problems but I treat as required in the fall.
Also because of my poly hives I have to do the OAV from below the screened bottom board. Bees never come in contact with the heating elements and I have had great mite drop results after treatment and confirmed by a follow-up treatment after a couple of weeks to check on the effectiveness.


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## Brad Bee (Apr 15, 2013)

What kind of vaporizer are you guys referring to that you use outside the hive? 

And for clarification sake, I checked those hives on a Saturday afternoon. They were queenright. I OAV'd them that night, just after dark. I checked them the next Saturday and they were queenless.


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## Yukon Bees (Dec 29, 2014)

I use Varrox Vaporizer


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## Bkwoodsbees (Feb 8, 2014)

I have done alot of oav treatments with no problems. I haven't done any after dark wouldn't think that would be a problem. I say something else was going on.


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## Brad Bee (Apr 15, 2013)

Yukon Bees said:


> I use Varrox Vaporizer
> View attachment 30341


Same thing I use. I would be interested in having one that blows the vapor into the hive, just to keep the heat out of the hive. I haven't set one on fire but I have scorched some wood on one of them. Many of my bottom boards are made from recycled 40 year old western red cedar. It's dry as a bone and highly flammable.


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## snl (Nov 20, 2009)

Brad Bee said:


> I would be interested in having one that blows the vapor into the hive, just to keep the heat out of the hive.


Check out the new ProVap110. It does exactly as you wish..........


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## Tenbears (May 15, 2012)

I have used OAV treatment to control mites for going on 7 years now. First with a homemade Vaporizer, then with a Varrox when SNL started carrying them. I treat around 100 hives most of the year and have never had queen loses that I can attribute to use of OAV. 
I am considering more seriously every day about going to the Provap110. Especially since I discovered that my 2017 ford P/U has a converter build into it. with an outlet right on the dash. 
Go to SNL'S sight he has a video of the Provap110 there you can watch, It is the coolest vaporizer on the market today! a real convenience and time saver. I have 3 Varrox now one still new to save time as it is precious to me, and the Provap110 looks as though it will beat them hands down.


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## BernhardHeuvel (Mar 13, 2013)

Tenbears said:


> discovered that my 2017 ford P/U has a converter build into it. with an outlet right on the dash.


Wait, my Ford pickup also has a small roll-down curtain on the dash and it says: power point. Is it just a usual car cigar jack type of power access? Or is this a converter?


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## Tenbears (May 15, 2012)

BernhardHeuvel said:


> Wait, my Ford pickup also has a small roll-down curtain on the dash and it says: power point. Is it just a usual car cigar jack type of power access? Or is this a converter?







Mine has a power point that looks like a cigarette lighter jack. then beside it it has a regular 3 prong plug like in the house.


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## BernhardHeuvel (Mar 13, 2013)

Very nice. Ok, I don't have that. Cool feature.


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## bee keeper chef (Nov 1, 2015)

I had a queen outside of a hive after treatment getting balled she was not marked and I know that I marked the queen. the next day I looked in the hive and she was still there I have no idea where that queen came from. I try to keep my queens marked its the only way I know if it is the same queen if they superseded or swarmed. To my knowledge I have not lost a queen to OAV


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## Brad Bee (Apr 15, 2013)

snl said:


> Check out the new ProVap110. It does exactly as you wish..........


I watched the video, it's definitely impressive. I'd have a hard time justifying that with 8 current hives. 

How do you keep the bees from propolizing the hole?


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## snl (Nov 20, 2009)

Brad Bee said:


> I watched the video, it's definitely impressive. I'd have a hard time justifying that with 8 current hives.
> I agree
> How do you keep the bees from propolizing the hole?


You don't, the bees will propolize it. But it's easy to open again. You can always do it from the front. Just get a paint stick, cut it to length and drill a hole it it for the stem. An effective (not great) vapor block. Get a couple a paint sticks, do the same and when you pull the vaporizer out the paint stick stays blocking the vapor and you just keep on moving down the line.....


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## johno (Dec 4, 2011)

I just drilled holes in the back bottom edge of all my hives to take a certain sized dowel cut them and made plugs. So remove the plug treat and replace the plug.
Johno


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## shinbone (Jul 5, 2011)

I've been OAV'ing my ~10 hives for about 4 years. The treatment has never caused queen loss. People have been OAV'ing hives in Europe for decades without it harming queens. Properly done, OAV itself doesn't kill queens.

Brad Bee - not necessarily saying you are doing something wrong, but OAV doesn't by itself harm queens, so your queen loss is either an unfortunate coincidence, or something is up with the particular hive or your equipment, materials, or method.

JMHO



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