Whether to vape with oxalic acid after completion of Apivar (Amitraz)?

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Amari

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The hives in the West Suffolk BKA club apiary were treated with Apivar for nine weeks late August-end October. I am minded to OA vape each hive once any time soon but our chairman suggests that this is unnecessary. I would not plan to check for brood. I'd be grateful for the opinion of the forum.

[My own hives received Apivar August thro' September and I vaped them yesterday]
 
Ive arbitrarily treated this week anyway

I plan to do exactly the same perhaps either this weekend or the following weekend (more likely). I know it's somewhat arbitrary, but I'd like to try to get in one round of treatment when brood numbers are likely to be low.

With regards to the OP's post, I'd suggest the response depends upon the Chairman's reasons for suggesting it's not necessary (ie. not at all, or just not quite now). My belief is that there's good reason to try to treat for varroa when brood numbers are minimal, but exactly when that might be is arguable and will most likely vary by location. David Evans did a good piece a couple of weeks back that might be a useful way forward in this case:

https://theapiarist.org/broodless/

James
 
Its neccessary if mite numbers are up rather than unnecessary based on an opinion.
Ive arbitrarily treated this week anyway
I plan to do exactly the same perhaps either this weekend or the following weekend (more likely). I know it's somewhat arbitrary, but I'd like to try to get in one round of treatment when brood numbers are likely to be low.

With regards to the OP's post, I'd suggest the response depends upon the Chairman's reasons for suggesting it's not necessary (ie. not at all, or just not quite now). My belief is that there's good reason to try to treat for varroa when brood numbers are minimal, but exactly when that might be is arguable and will most likely vary by location. David Evans did a good piece a couple of weeks back that might be a useful way forward in this case:

https://theapiarist.org/broodless/

James
Thanks both.
The club apiary is about eight miles away and has restricted access so the colonies don't get the TLC that mine do. Having said that, I was too lazy to check my own hives for broodlessness by David Evans' method of checking for the absence of bicuit-coloured cappings on the varroa board, described in his excellent article.
David advises early rather than mid-winter OA treatment - but it's interesting to speculate whether his timings in Scotland apply to Suffolk!
 
David advises early rather than mid-winter OA treatment - but it's interesting to speculate whether his timings in Scotland apply to Suffolk!

If I recall his argument correctly, he suggests that brood numbers will already be starting to rise by midwinter hence treating earlier, but I'd imagine the time of minimal brood will vary by location depending on how the bees react to what's going on in the area they forage over. I know people have posted here in the last few days reporting that on sunny days their bees are still foraging, yet mine appear to have called it a year regardless of the weather and despite being in the allegedly balmy south west (perhaps I misunderstood and it was "barmy"). We're on an exposed hilltop at 125m above sea level however, and even between here and Taunton, much of which is within 15m of sea level as far as I recall and little over ten miles away, there's a significant difference. Two Sundays ago I drove into Taunton in the evening to pick my daughter up. According to the car it was 4°C here when I left home, 7°C in the centre of Taunton, and 3°C when I got back. Expecting the bees to behave the same way in either location is probably not going to work out as planned.

James
 
I’d be inclined to leave any treatment till end of December, I recently posted a video a few weeks ago of brood and eggs in nucs. I’ve traditionally done mine over the Xmas holidays and inspected many over the years and in my area that appears to be the best time. Big colonies appear to come into lay at the end of Jan, nucs last year started laying middle of Feb. Obviously weather/colonies so ball park. There dose appear to be a recent trend with some wanting it done earlier every year😉
As to if it’s necessary… winter treatments are never meant to be a treatment for the current season, they give you a clean as possible start for the year in front. 1 mite killed now will be many more come May/June. Having also been through resistance building to Apistan many years ago Winter trickling back then certainly helped our winter losses compared to many! Some are suggesting we are getting to that stage with apivar ATM. You will do no harm treating your hives and certainly the bees will benefit so really it’s a no brainer, just leave it till the end of the month.
 
I think LASI found that the best time to find them broodless was early to mid December, I've found that, regardless of weather, once December comes to an end they start picking up their brooding again
 
I think LASI found that the best time to find them broodless was early to mid December, I've found that, regardless of weather, once December comes to an end they start picking up their brooding again

LASI is probably a better source (in terms of timing) for many people in the UK than the paper David Evans referenced, which I think was based on research done either in Canada or northern USA. It showed the broodless period exceptionally early compared with what I imagine most of us in the UK would expect.

I can't find any reference to this sort of information from LASI, but I just found this which may be informative:



I've not watched the full thing yet, but the tables presented at the start suggest to me that when Bernard Mobus did his work in the mid 1970s the bees were more likely to be broodless in mid to late November, but there's quite a bit of variation and no guarantee that it will happen at all.

James
 
Having watched the recording, a few things occur to me. No answers really, just lots more questions that perhaps mean I need to do some more research:

I'm really not convinced about his suggestion of not insulating hives. If we accept the idea that water can condense on a cold crown board and drip back down onto the cluster then insulating the crown board seems like the logical conclusion. Matchsticks and increased ventilation not only rob the colony of heat, but also of water that they may well need.

But, what's the evidence for dripping condensation from the crown board causing harm? I've never thought to question it before. It was something I accepted as fact when I did my initial training course. Does it exist? Or has it become a beekeeping myth as a result of people opening up dead colonies, finding them damp and assuming the two must be connected? I know people say that it's the damp that kills bees, but are drips from a crown board sufficient to do so (particularly if you have brood frames with wide top bars and many of the drips may not actually land on the bees anyhow?)

And if bee behaviour has evolved to suit living in cavities in trees, they surely must be used to better insulation than they get in a standard wooden hive anyhow. What harm can be done by insulating to the same levels as they would experience "in the wild"?

I get the impression from the video that raising brood may be an integral part of the bees temperature management behaviour once they are clustered. If that's true, could it be that a broodless period is more likely to occur once there's little available forage, but before it's cold enough to trigger them to cluster?

If the broodless or "minimal brood" period is very variable even amongst colonies in the same apiary, monitoring dropped brood cappings as a proxy as suggested by David Evans in the link I posted earlier might be a good way to do so. But my mesh floors would be very poor for that. David Evans has a photo of a mesh floor he uses in the same post I already mentioned. It's one of Pete Little's. Rather than a fairly tight woven wire mesh such as mine it looks as though he used an expanded metal mesh with larger holes (so "stuff" is probably more likely to fall through). Can anyone confirm that?

However, once you manage a reasonable number of hives, especially over a number of sites, monitoring capping drop repeatedly until you get to a minimum is likely to be impractical, so what's a viable alternative then? Hit them with OA every two or three weeks between the start of November and the end of December? Not sure that's particularly practical either, nor allowed by the licensing for Apibioxal, for instance.

James
 
Same sort of area as Amari. My varroa boards were showing little evidence of brood uncapping so I did an OAV about a week ago. Checked the boards yesterday and a heavy varroa drop, and again minimal cappings. I normally only do one vape now, but in view of heavy drop will do a second. I use Apiguard in August
 
I'm testing 3 or 4 Vapes 5 days apart, that *should* kill most of the mites sealed in with any brood currently.

See how that plays out over next year.
 
In the closing summary of his recent blog posting: Repeated oxalic acid vaporisation - The Apiarist David Evans shows some scepticism about the repeated use of oxalic vaping as is often recommended to be used; eg. on this forum. He also points out that he finds that Apivar is better at reducing Varroa levels. So, effectively, maybe he agrees with @Amari 's club chairman....or maybe it's the other way round.

"Repeated oxalic acid vaporisation is regularly proposed as the solution to Varroa but I’m certainly not confident that the data is there to support this claim."
 
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In the closing summary of his recent blog posting: Repeated oxalic acid vaporisation - The Apiarist David Evans shows some scepticism about the repeated use of oxalic vaping as is often recommended to be used; eg. on this forum. He also points out that he finds that Apivar is better at reducing Varroa levels. So, effectively, maybe he agrees with @Amari 's club chairman....or maybe it's the other way round.

"Repeated oxalic acid vaporisation is regularly proposed as the solution to Varroa but I’m certainly not confident that the data is there to support this claim."
He said -

It therefore makes sense that three treatments at five day intervals should be sufficient. This period comfortably covers a complete capped brood cycle (assuming there is no drone brood in the colony) which is 12 days long.

If there is drone brood present you would theoretically need four treatments at 5 day intervals to be sure of covering the 15 day capped brood cycle of drones.

There is also a bit in the QA section -

Pete Little’s final recommendation on repeat treatments was 3 x five days followed by a fourth treatment after four days.

https://beekeepingforum.co.uk/threads/oxalic-acid-sublimation-frequency.31813/page-2#post-446328
Also his thoughts ^^

Like Swarm said, try stuff and see if it works.

I went years with zero treatments and the bees were fine, go figure.
 
In the closing summary of his recent blog posting: Repeated oxalic acid vaporisation - The Apiarist David Evans shows some scepticism about the repeated use of oxalic vaping as is often recommended to be used; eg. on this forum
you are just picking the words that suit you, big difference between multiple treatments which a few on here conduct (can't see it recommended) and the three/four treatments which most recommend
 

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