Varroa Alert

[GuyNir]

Even though nobody is quite certain of how oxalic and thymol kills the mite, resistance to these is unlikely, but could happen. Due to my medical background, it makes sense to me to ring the changes. I use thymol in Autumn and one dose of OAV in Nov/Dec. Not had any losses from varroa yet.
If counts did rise unexpectedly I would use extra OAV doses

Did just that this year. Thymovar in Autumn and a single OAV couple weeks ago.

 

[elainemary]

Simple - do it every five days
Why disbelieve (or reinvent) something that has been modelled, trialled, used regularly for years and proven effective.

Not a case of disbelieveling, motivation is to understand

 

[Erichalfbee]

Not a case of disbelieveling, motivation is to understand

So you may be on the cusp of trying it?
But an inordinate amount of anecdotal evidence stretching back a number of years is insufficient to convince you because you need foolproof numbers?
Or you are going to try it but need to know exactly how it works?
Or have I misunderstood?

 

[elainemary]

So you may be on the cusp of trying it?
But an inordinate amount of anecdotal evidence stretching back a number of years is insufficient to convince you because you need foolproof numbers?
Or you are going to try it but need to know exactly how it works?
Or have I misunderstood?

Yes on the cusp of trying it next year as have use Amitraz for last few seasons so need to rotate, want to work out why it’s effective. It’s the way I think, need explanation and logic.

 

[Erichalfbee]

Yes on the cusp of trying it next year as have use Amitraz for last few seasons so need to rotate, want to work out why it’s effective. It’s the way I think, need explanation and logic.

Some things you have to take on trust.
I watch tele but don’t have enough of an idea how it works to make one from scratch.
There are plenty of explanations already in this thread.
But if you throw HOW does varroa kill mites into the mix you are whistling in the wind.

 

[jenkinsbrynmair]

Yes on the cusp of trying it next year as have use Amitraz for last few seasons so need to rotate, want to work out why it’s effective. It’s the way I think, need explanation and logic.

So what calculations did you make before chucking insecticide onto your bees?

 

[ShinySideUp]

I don't know how it works and I don't need to, it just does. I don't know exactly how a kidney works but as a non-doctor I just have to be glad it does.

Did my OA trickling today and three of my four hives had bees on top of the frames and they were quite active despite the cold -- not sure about the fourth one, as there were no bees easily visible (but they do have a heavily filled nadir so I expect they were there) but I don't like to leave the hives open in the cold weather so didn't push the point. Nothing I can do until Spring if the hive has perished anyway.

 

[pargyle]

Some things you have to take on trust.
I watch tele but don’t have enough of an idea how it works to make one from scratch.
There are plenty of explanations already in this thread.
But if you throw HOW does varroa kill mites into the mix you are whistling in the wind.

I'm too old now to waste what's left of my life looking for explanations for everything ... I'm happy to push buttons that someone's demonstrated make whatever I want to happen, happen... I'm inquisitive up to a point but some things you just have to accept. In beekeeping it's often the science that follows the practice so I just practice and let the navel gazers catch up when they get round to it ... and even then the experiments they do don't always prove the practical observations of those of us actually keeping bees ...

 

[charlievictorbravo]

.... In beekeeping it's often the science that follows the practice so I just practice and let the navel gazers catch up when they get round to it ... and even then the experiments they do don't always prove the practical observations of those of us actually keeping bees ...

The research into OA as a treatment against varroa done by LASI in 2013 and published in 2015 was, I think, intended solely to compare three methods of delivery (spraying, drizzling and vaporising) at three different doses (four in the case of vaporisation). In order to do the comparison, they had to remove the brood before starting treatments to get a fair comparison. I don't think they really expected beekeepers to open up their hives, lift out frames and remove all brood as a matter of routine.

The LASI research showed vaporisation with 2.25g of OA (not Apibioxal because it was not invented then) was safe and the most effective treatment. As Phil has pointed out above, beekeepers are ahead of the academics and realised that OA did not kill bees and that if you vape every 5 days for the length of the brood cycle, you catch all the varroa as they emerge with the bees from brood cells.

Why 5 days? Well, I think came about because 5 days is the minimum "phoretic" period before a mite returns to a brood cell - get 95% the mites before they return to the safety of a cell and you're nearly there. Do it three times, five days apart and you've pretty much covered the worker bee reproductive cycle or four times if you've got drone brood (or still have a big mite drop after 20 days).

We don't know for sure how OA kills mites - do the mites somehow ingest the treatment or do they absorb it? Does it burn their feet as they move about on bees and they let go and die under the hive? Does the acid poison them through absorption by their soft mouth parts? Beekeepers don't need to know the answer to these questions but others are curious.

A lot of stuff was written about varroa before we found out that the varroa are not phoretic (meaning in a purely transport phase) when on bees outside the cells - they are parasitizing the bees. They tuck themselves between the abdominal plates of adult bees primarily on the underside of the abdominal region on the left side of the bee and they eat the bees' Fat Body (an essential organ for many different reasons). They seem to be fairly safe there but we don't know how long they stay at one feeding site or indeed on one bee so I think they are vulnerable to OA when they leave a feeding site to find another, which is why the OA crystals need to have an active life - to be effective until the next treatment. Having a broodless period is not the panacea it was once thought to be. We now know that it means that the mites are all feeding on adult bees, reducing their lifespan, reducing their ability to regulate temperature and humidity, reducing their ability to deal with toxins, etc.

Bees do nothing invariably and reacting to OA treatments is no exception. I've had one or two colonies that for some inexplicable reason needed five OA treatments to get the mites under control. Vaping is a simple procedure that is made difficult by having to clean up after Apibioxal leaves sugary residues in equipment - ah well, can't have everything.

CVB

 

[madasafish]

Bees do nothing invariably and reacting to OA treatments is no exception. I've had one or two colonies that for some inexplicable reason needed five OA treatments to get the mites under control. Vaping is a simple procedure that is made difficult by having to clean up after Apibioxal leaves sugary residues in equipment - ah well, can't have everything.

CVB

Covering the tray with aluminium foil so deposits are left on the foil saves some cleaning

 

[Erichalfbee]

The research into OA as a treatment against varroa done by LASI in 2013 and published in 2015 was, I think, intended solely to compare three methods of delivery (spraying, drizzling and vaporising) at three different doses (four in the case of vaporisation). In order to do the comparison, they had to remove the brood before starting treatments to get a fair comparison. I don't think they really expected beekeepers to open up their hives, lift out frames and remove all brood as a matter of routine.



CVB

Oh I think they did
I was at a presentation by Ratnieks, after all this got going around the time they were selling their hygienic queens, and that is exactly what he was advocating we do in winter

 

[elainemary]

The research into OA as a treatment against varroa done by LASI in 2013 and published in 2015 was, I think, intended solely to compare three methods of delivery (spraying, drizzling and vaporising) at three different doses (four in the case of vaporisation). In order to do the comparison, they had to remove the brood before starting treatments to get a fair comparison. I don't think they really expected beekeepers to open up their hives, lift out frames and remove all brood as a matter of routine.

The LASI research showed vaporisation with 2.25g of OA (not Apibioxal because it was not invented then) was safe and the most effective treatment. As Phil has pointed out above, beekeepers are ahead of the academics and realised that OA did not kill bees and that if you vape every 5 days for the length of the brood cycle, you catch all the varroa as they emerge with the bees from brood cells.

Why 5 days? Well, I think came about because 5 days is the minimum "phoretic" period before a mite returns to a brood cell - get 95% the mites before they return to the safety of a cell and you're nearly there. Do it three times, five days apart and you've pretty much covered the worker bee reproductive cycle or four times if you've got drone brood (or still have a big mite drop after 20 days).

We don't know for sure how OA kills mites - do the mites somehow ingest the treatment or do they absorb it? Does it burn their feet as they move about on bees and they let go and die under the hive? Does the acid poison them through absorption by their soft mouth parts? Beekeepers don't need to know the answer to these questions but others are curious.

A lot of stuff was written about varroa before we found out that the varroa are not phoretic (meaning in a purely transport phase) when on bees outside the cells - they are parasitizing the bees. They tuck themselves between the abdominal plates of adult bees primarily on the underside of the abdominal region on the left side of the bee and they eat the bees' Fat Body (an essential organ for many different reasons). They seem to be fairly safe there but we don't know how long they stay at one feeding site or indeed on one bee so I think they are vulnerable to OA when they leave a feeding site to find another, which is why the OA crystals need to have an active life - to be effective until the next treatment. Having a broodless period is not the panacea it was once thought to be. We now know that it means that the mites are all feeding on adult bees, reducing their lifespan, reducing their ability to regulate temperature and humidity, reducing their ability to deal with toxins, etc.

Bees do nothing invariably and reacting to OA treatments is no exception. I've had one or two colonies that for some inexplicable reason needed five OA treatments to get the mites under control. Vaping is a simple procedure that is made difficult by having to clean up after Apibioxal leaves sugary residues in equipment - ah well, can't have everything.

CVB

Thanks that’s a good summary of what is known. Maybe some of your colonies needed more rounds because at the end of the treatment they were invaded by mites (down to robbing?).
Reason why I was asking about the effectiveness of 5 days vs 7 days is down to one of the facts you’ve pointed out. When new bees emerge, varroa jumps into new cells about to be capped. Oxalic acid is only effective for 3 days after sublimation by bees walking it around and thereafter effects much reduced. So what if mites emerge from newly uncapped cells and then jump into cells day 4 or part of day 5 so capped before the next treatment. But what you’ve explained is they don’t, as they stay out of the cell for 5 days. Hadn’t registered this so thanks.

Randy Oliver’s work showing 75-80% mites killed based on 7 days x3 rounds, effectiveness isn’t good enough. If start with 1000 mites and 3 rounds of treatment within 3 brood cycles the mites could be back up to the start point, assuming a doubling of mites every cycle.

Can now see why 5 days will be more effective and your explanation has helped me understand why.
Thanks
Elaine

 

[Erichalfbee]

I do three or four vapes in September and sometimes one in December and that's it.
Three years ago I had one colony that was vaped 7/8 (forget) times and dropped nigh on 8K mites during treatment. I gave up and put in Amitraz after which there was little drop so the OAV more or less cracked it. The following year this colony gave me five supers of honey

 

[elainemary]

I do three or four vapes in September and sometimes one in December and that's it.
Three years ago I had one colony that was vaped 7/8 (forget) times and dropped nigh on 8K mites during treatment. I gave up and put in Amitraz after which there was little drop so the OAV more or less cracked it. The following year this colony gave me five supers of honey

Thanks that’s helpful. Do you rotate treatments or only use Oxalic acid?

 

[Erichalfbee]

Thanks that’s helpful. Do you rotate treatments or only use Oxalic acid?

Only Oxalic since 2010
Rooftop colony got Amitraz

 

[jenkinsbrynmair]

I don't think they really expected beekeepers to open up their hives, lift out frames and remove all brood as a matter of routine.

Yes they did/do - I've asked the question directly of Ratnieks when he was on his Queen selling tour and he was specific in his expectation that beekeepers should open up midwinter and rip out any brood. He blankly refused to contemplate or even discuss the 3x5 system.

 

[Ian123]

Yes they did/do - I've asked the question directly of Ratnieks when he was on his Queen selling tour and he was specific in his expectation that beekeepers should open up midwinter and rip out any brood. He blankly refused to contemplate or even discuss the 3x5 system.

He may have just followed on from the original trickle research/advice that also advised removal of brood. And wasn’t the lasi work done solely as a winter treatment? Ian

 

[BeeKeyPlayer]

Why 5 days? Well, I think came about because 5 days is the minimum "phoretic" period before a mite returns to a brood cell - get 95% the mites before they return to the safety of a cell and you're nearly there. Do it three times, five days apart and you've pretty much covered the worker bee reproductive cycle or four times if you've got drone brood (or still have a big mite drop after 20 days).

Thanks for that explanation. While I have been happy to accept and use the advice/recommendation for 5-day intervals, I was curious to know the thinking behind it. Apparently (I'm not at all sure) it is a GB idea, possibly started by Peter Little from his own experience, and spread on this forum. But it does not appear to have crossed the pond, nor does the timing of brood development make it obvious that 5 days is preferable to 6 or 7.

 

[BeeKeyPlayer]

Thanks that’s helpful. Do you rotate treatments or only use Oxalic acid?

Only Oxalic since 2010
Rooftop colony got Amitraz

And, of course, mites don't develop resistance to OA. That's worth knowing and NOT something I learned from NBU publications.

 

[BeeKeyPlayer]

Oh I think they did

You're right (though I know you don't need me to say so).
From the LASI website, https://www.sussex.ac.uk/lasi/documents/pamphlet-sublimationtreatmentoxalicacid-a4-1page-2016.pdf
'It is best to check hives immediately or a few days before application and remove or scrape out any small patches of capped brood.'