Oxalic sublimation for Autumn Treatment

[melias]

Is there a consensus on the use of sublimated oxalic as an autumn treatment?

I've seen some posts suggesting 3 treatment 5 days apart. Should the amount of sublimated oxalic be the same as during a 1x winter treatment?

 

[pargyle]

Is there a consensus on the use of sublimated oxalic as an autumn treatment?

I've seen some posts suggesting 3 treatment 5 days apart. Should the amount of sublimated oxalic be the same as during a 1x winter treatment?

The reason for 3 x 5 days is that if there is brood present in the hive then there will always be mites hidden in the cells that you need to catch with the susbequent treatments. The five days cover the next emergent brood cycle - three times with an interval of 5 days between each and you effectively cover a full brood cycle.

In the middle of winter there is unlikely to be much brood so the treatment will get a good result with just one go at it.

Same quantity of OA in the Varrox winter or summer ..

 

[JWF]

Same quantity for each vape - not spread out over three.

Personally I do three values in the winter too, none of that hacking out of brood that LASI suggested

 

[MelC]

I'm confused by this. I read that worker cells are capped for between 10 & 12 days .. so doesn't the treatment need to extend beyond this period (12+ days) to catch the mite that is capped just before the first treatment? I assume that treating every 5 days is timed to catch mites in the phoretic phase of their cycle during this 12+ day period. So should it be 4 treatments at 5 days .. 15 days in total?

 

[Millet]

I do four to be on the safe side.

 

[Erichalfbee]

I do three with a fourth four days after the third, if the drop warrants it

 

[charlievictorbravo]

I'm confused by this. I read that worker cells are capped for between 10 & 12 days .. so doesn't the treatment need to extend beyond this period (12+ days) to catch the mite that is capped just before the first treatment? I assume that treating every 5 days is timed to catch mites in the phoretic phase of their cycle during this 12+ day period. So should it be 4 treatments at 5 days .. 15 days in total?

And drone cells, for instance, remain capped for 15 days so vaping on days 0, 5, 10, 15 should get them all. There is some evidence that Oxalic Acid crystals remain "active" in a hive for far longer than 5 days so 4 treatments should be enough. Whether, at this time of year, there would be any drones is open to debate.

CVB

 

[MelC]

And drone cells, for instance, remain capped for 15 days so vaping on days 0, 5, 10, 15 should get them all. There is some evidence that Oxalic Acid crystals remain "active" in a hive for far longer than 5 days so 4 treatments should be enough. Whether, at this time of year, there would be any drones is open to debate.

CVB

Good point about drones; not an issue at the year end but could be an issue at other times. 0, 5, 10 & 15 it is then.

 

[jeff33]

Does it kill brood though? Or is it just the direct contact of oxalic drip that kills brood?

 

[Finman]

.
I ask again.... Other countries use 7 days cycle in sublimation. From where this forum has got 5 days?

And sublimation is not invented in Britain.

 

[Erichalfbee]

.
I ask again.... Other countries use 7 days cycle in sublimation. From where this forum has got 5 days?

And sublimation is not invented in Britain.

I have no idea but you are right. Most vaping cycles described outside U.K. Are 7 days. If oxalic has a residual affect for a few days after vaping and mites have a minimum phoretic stage of 4 days then 7 days makes sense

 

[Etton]

Does it kill brood though? Or is it just the direct contact of oxalic drip that kills brood?

Not sure what do others think?

 

[Eyeman]

Does it kill brood though? Or is it just the direct contact of oxalic drip that kills brood?

There is no resported harm to brood from Vapourising.

 

[Eyeman]

.
I ask again.... Other countries use 7 days cycle in sublimation. From where this forum has got 5 days?

And sublimation is not invented in Britain.

This a a discussion on the Bee-L list (largely commercial North American beekeepers).

I have found for me in my area of South Carolina that 6 treatments every
> 5 days works well. No adverse effects and winter losses have been very few
> if any. We seldom get a bloodless period so I have to be aggressive. The
> seven day 3 treatment schedule did not work for me.


Mark, I hear this from many others. If you took any mite counts during
your experimentation, could you please email me personally?

They seem to be coming round to shorter intervals between treatments.

 

[Erichalfbee]

This a a discussion on the Bee-L list (largely commercial North American beekeepers).



They seem to be coming round to shorter intervals between treatments.

Interesting. I have never tried longer intervals so have no personal experience. If the drop continues after the third I shorten the interval

 

[Beefriendly]

They seem to be coming round to shorter intervals between treatments.

That is interesting Eyeman and quite relevant to one of my hives that I found had a horrendous varroa load; although no DWV symptoms were seen. They have already had 4 x 5 day treatments and after the 4th they still dropped over 500 mites in 48 hours, I had already decided I was going to continue treating and the 5th vape is due tomorrow and likely a 6th to follow.

 

[Erichalfbee]

That is interesting Eyeman and quite relevant to one of my hives that I found had a horrendous varroa load; although no DWV symptoms were seen. They have already had 4 x 5 day treatments and after the 4th they still dropped over 500 mites in 48 hours, I had already decided I was going to continue treating and the 5th vape is due tomorrow and likely a 6th to follow.

Please let us know how this goes.
I have a colony showing similar symptoms though I have only just done the second vape.
Horrendous drop and no obvious DWV bees with either affected wings or shortened abdomens.
The first five day's drop is 780 and it was 200 on the morning after the second vape.

Didn't Charlievictorbravo have something similar last year?

 

[Finman]

I'm confused by this. I read that worker cells are capped for between 10 & 12 days .. ?

3 days egg and 5 days larva feeding and then cap.... = 8 days

21 -8 = 13 days as capped

 

[Erichalfbee]

Capped at 8/9 emerged at 21....that's 13/12

 

[Finman]

Capped at 8/9 emerged at 21....that's 13/12

What!!!!....is 8/9 ....

What means 13/12....

Larva and pupa.... The cell is capped one day before pupa formation. For example the cell is capped when larva makes the pupa silk.

And when you nurse your hives, you surely need to count hours in the brood cycle.

I can read that larva stage is 5.5 days. But where heck you need that accuracy. Is it better that you treat the larvae begore it is capped.