Effectiveness of OA sublimation in practice

[beeno]

Some people on the forum end up vaping OA more than 3 times every 5 days, which makes one think that it is not a very effective treatment, and then resort to another treatment with considerable drop. I found the following quote from scientific beekeeping which may throw some light on the matter.
Quote
Oxalic Acid: Part 2 Heat Vaporization and Other Methods
How does oxalic vaporization work? In the CRC Handbook of Chemistry and Physics we find that upon heating oxalic acid, the water of hydration boils off first, then at 315°F the oxalic acid starts to sublime (go directly from solid to vapor), and finally at 372°F any oxalic acid which has not yet sublimed decomposes to initially to formic acid and carbon dioxide, and then to CO2, carbon monoxide, and water). One of the problems with some vaporizers is that they get too hot too quickly and decompose, rather than evaporate the acid.
During application, the warm fog of tiny crystals (it’s no longer vapor shortly after leaving the vaporizer) rises within the confines of the hive bodies, and grow on surfaces inside the hive, including on the setae of at least some bees:
Unquote
I have seen a foto of the inside of a hive after being covered in the crystals and it is a big task for the bees to keep cleaning it up time and time again.

 

[pargyle]

I think the problem that some people have had with multiple vapings is more down to re-infestation than it is to it being an ineffective treatment. I would be more inclined to believe the Sussex University research which showed a 97% kill rate. Of course ... there is the need to cover at least three brood cycles to gain the maximum benefit unless the colony is broodless but ... if they are robbing a failing hive somewhere in the vicinity then no treatments are going to be effective.

https://www.sussex.ac.uk/lasi/sussexplan/varroamites

 

[Erichalfbee]

I would bet on re infestation too
How else would you explain a high mite count on captured returning foragers which is what I found a few years ago when I had to vape a hive 7 times to get rid of 8 thousand mites?

 

[Apple]

I would bet on re infestation too
How else would you explain a high mite count on captured returning foragers which is what I found a few years ago when I had to vape a hive 7 times to get rid of 8 thousand mites?

Indeed
Randy Oliver the American beekeeping bioscientist commented that some beekeepers in the vicinity of his large Californian apiary sites deliberately did not treat their bees against the varroa mite, and despite his own control which kept the varroa population very low, and at an acceptable level, VARROA BOMBS were being created in the untreated colonies, which indeed did infest his treated colonies.
Beekeepers in this very small island of ours have a responsibility to others to control pests and diseases.... not just varroa and the virus they carry...
Do not import bees ( including queens) from overseas.
Register on BEEBASE ( at very least you will get informed of outbreaks of AFB and or EFB in your area)

When varroa was first found in the South Devon Cockington Apiary ( not so far from Buckfast Abbey!) it was made a notifiable disease,,,,, history has shown that it should have been locked down then.

Treat all your colonies for varroa and encourage others to do so... it is the flea that carries the novel imported pathogenic virus we are seeing... beekeepers importing the rats ( queens packages etc)
Did anyone note the comments on varroa that Proffessor Grace Mc.C made yesterday evening on the BIBBA webinar about studies made on the genetic make up of varroa?
Very interesting!
Mytten da

 

[Mint Bee]

I was going to comment on my experience with OA vaping, but now Hoppy has managed to include his favourite topic of banning bee imports, I don't think I'll bother. Seems to be one source for threads to degenerate into uncivilised rants needing moderator intervention.

Shame because the other advice regarding treating and registering I thought was positive

 

[Erichalfbee]

I was going to comment on my experience with OA vaping, but now Hoppy has managed to include his favourite topic of banning bee imports, I don't think I'll bother. Seems to be one source for threads to degenerate into uncivilised rants needing moderator intervention.

Shame because the other advice regarding treating and registering I thought was positive

No.
What you do is post as you intended and ignore the import bits
It might take one person to start a spat but it takes others to keep it going.
Pretty soon Dave’s post disappears as the thread progresses.

 

[Apple]

I was going to comment on my experience with OA vaping, but now Hoppy has managed to include his favourite topic of banning bee imports, I don't think I'll bother. Seems to be one source for threads to degenerate into uncivilised rants needing moderator intervention.

Shame because the other advice regarding treating and registering I thought was positive

Why control Varroa mite???

Varroa mite spreads viral diseases, possibly one of the most virulent vectors of disease
Possibly our population of bees in these islands could evolve natural defense / varroa tolerance etc if the Varroa mite population was stable.
Grace hinted in her BIBBA webinar that possibly our population of Varroa mite was being augmented by imported mites. These mites seem to have have a slightly different genetic make up that the endemic bee population has not had time to evolve any defense or tolerance to.

We are unlikely to ever rid our bees of Varroa mite in the UK, but we can help them to evolve a stable population if we stop introducing new genetic varieties with imported bees.

Varroa, the virus they transmit and importing bees are linked, I can not see how a considered response can be deemed to be an uncivilised rant?

Yeghes da

 

[gmonag]

Some people on the forum end up vaping OA more than 3 times every 5 days, which makes one think that it is not a very effective treatment, and then resort to another treatment with considerable drop. ...

What has been happening is that the mite drop is very high and continues after the 3-4 vapes. That does not indicate an ineffective method, on the contrary.
They then switch to apivar or whatever and "fix" the problem, presumably indicated by the mite drop reducing. This indicates a less effective treatment in my view.

 

[madasafish]

What has been happening is that the mite drop is very high and continues after the 3-4 vapes. That does not indicate an ineffective method, on the contrary.
They then switch to apivar or whatever and "fix" the problem, presumably indicated by the mite drop reducing. This indicates a less effective treatment in my view.

In my case I did OA treatment in Late August.. After 4 vapes and still a large mite drop I switched to Apistan and the drop reduced This was late September . I removed the Apistan 6 weeks later (as instructions) with minimal mite drops then. This was early November.

In the extreme edges of the Peak District and at 150metres above sealevel, there are relatively few bees flying In October let alone November (see now as the weather has been cold , cloudy and damp) so if the infestation was due to bees from another hive then the drop fall off would be expected as fewer bees would be flying and fewer mites therefore transferred.

Making diagnosis from afar is made more difficult due to the UK's many micro climates.. And if you live in the balmy South, you tend to forget what cold weather is...

 

[Nige.Coll]

I read some research a while ago regarding using OA sublimation when brood was present.
The findings of the research were that while brood was present the efficacy of the 3 treatments 5 days apart was around 70%.
This may seem low but it makes it roughly on par with the efficacy of Apiguard.
Obviously the results depend on the amount of brood in the hive at the time of treatment and the usual other factors, colony size, weather, humidity and temperature.
The major issue with treating with OA sublimation with brood present is the crafty mites. They hide below the larvae in the pool of food up to 18 hours before the cell is sealed. No one is sure exactly how long the phoretic stage is either as it can vary.

Generally I find it works well enough, if you can time the treatment with a brood break it makes it easier. There seems to be a brood break around early September where I am and I take full advantage of that.

 

[Apple]

What has been happening is that the mite drop is very high and continues after the 3-4 vapes. That does not indicate an ineffective method, on the contrary.
They then switch to apivar or whatever and "fix" the problem, presumably indicated by the mite drop reducing. This indicates a less effective treatment in my view.

An interesting hypothesis, we had a Masters student working with the B4 project a few seasons back and by monitoring the varroa sticky boards, and carrying out alcohol washes, it was found that the sticky board were not reflecting the mite load in the colonies.

The only way surely to evaluate the phoretic population of mites would be to carry out an alcohol wash.

 

[BeeKeyPlayer]

No.
What you do is post as you intended and ignore the import bits
It might take one person to start a spat but it takes others to keep it going.
Pretty soon Dave’s post disappears as the thread progresses.

Hoppy?
Dave?
Are these other names for Apple?

 

[Erichalfbee]

Hoppy?
Dave?
Are these other names for Apple?

Yes

 

[The Poot]

Oh dear.....

 

[Murox]

An interesting hypothesis, we had a Masters student working with the B4 project a few seasons back and by monitoring the varroa sticky boards, and carrying out alcohol washes, it was found that the sticky board were not reflecting the mite load in the colonies.

The only way surely to evaluate the phoretic population of mites would be to carry out an alcohol wash.

Thats not entirely unsurprising, but its a valid observation. I have always wondered how counting the dead over a period of time and multiplying the count by X to give an approximation of infestation could really be a useful indicator. Washes of alcohol or sugar even performed on a given number or weight of bees certainly seems to offer a more believable indication.

 

[Murox]

Maybe I am just fortunate; I have found oxalic sublimation to be very effective. As recommended I carry out the procedure at times of no or very low brood and for 3 times. The results for me are very good and have been for the last 3-4 years. This autumn I chose to use amitraz mainly because of covid issues. I will vape again mid December - early January and see if there is any significant variance to previous years.

 

[Nige.Coll]

Hoppy?
Dave?
Are these other names for Apple?

The polite ones yeah

 

[Apple]

Maybe I am just fortunate; I have found oxalic sublimation to be very effective. As recommended I carry out the procedure at times of no or very low brood and for 3 times. The results for me are very good and have been for the last 3-4 years. This autumn I chose to use amitraz mainly because of covid issues. I will vape again mid December - early January and see if there is any significant variance to previous years.

Can you give a comparison of the drops of mite when using Amitraz strips and OA sublimation.
What method do you use to get the OA vapour into the colony.
I realise that this can only be anecdotal, but I found similar small drops of mite on the sticky board using the thymol based paste ( some years ago in large blue pots... now only available in sachets) to OA vaporisation from beneath the OMF with the Varrox wand.
The Varrox wand used under the OMF was not as effective as the ( Russian?) Varromoor fogger, but the best results in terms of mite drop have been with Vaping with the Sublimox using a vaping hood.
Generally I only seem to get a small mite drop, but this compares well with the alcohol wash.
The exception was with some imported Greek Buckfast type bees that I trialed as prospective surrogate brood for the queen rearing program, which seemed to have a large infestation of mite as they built up in the spring, perhaps this was an issue with the apiary site and the beekeeping capabilities of someone in that neighborhood as it was also the apiary where an EFB infected swarm with a marked queen moved in to an empty hive!

 

[Murox]

Can you give a comparison of the drops of mite when using Amitraz strips and OA sublimation.
What method do you use to get the OA vapour into the colony.
I realise that this can only be anecdotal, but I found similar small drops of mite on the sticky board using the thymol based paste ( some years ago in large blue pots... now only available in sachets) to OA vaporisation from beneath the OMF with the Varrox wand.
The Varrox wand used under the OMF was not as effective as the ( Russian?) Varromoor fogger, but the best results in terms of mite drop have been with Vaping with the Sublimox using a vaping hood.
Generally I only seem to get a small mite drop, but this compares well with the alcohol wash.
The exception was with some imported Greek Buckfast type bees that I trialed as prospective surrogate brood for the queen rearing program, which seemed to have a large infestation of mite as they built up in the spring, perhaps this was an issue with the apiary site and the beekeeping capabilities of someone in that neighborhood as it was also the apiary where an EFB infected swarm with a marked queen moved in to an empty hive!

I use a simple 'pan' type heater. Mostly from below the OMF. The style of hive I am using is a long deep homemade insulated wood design. The origin of the bees in these is local, here that probably means amm types, they were from an artificial swarm made by the local association. Another of these is headed by a daughter queen from an artificial swarm I created. The original varroa count was low anyway and has always remained so, maybe they are more hygienic than some who knows? – I count the dead if it “looks” like a lot after 24 hrs – the most I have ever counted was under 50, I have come to expect a small count of say 10 or so at the most, by the third vape it nil and often nil after the second. I wont see if there is a difference using amitraz until at least Dec/Jan.

My geographic situation is probably rather unusual though.

 

[maddydog]

Yes

Don't forget cheers