Oxalic treatment on brood break

[SireeDubs]

One of my colonies has superseded their queen (found old queen - from swarm last year - dead, and subsequent queen cell should've hatched about now).

I've always been told to treat a swarm with Oxalic, as in very early days all mites are phoretic. Following that logic, and after monitoring, can I treat this superseded colony if required? There is no brood left to be concerned about, and virgin prob not mated yet. It may be that there is no treatment required, in this case, the info will just go in my book if and when I ever need it again! Colony was last treated late December 2015.

Questions are:

1. Am I right about thinking of treating with OA?
2. If I treat, can it harm virgin queen chances of successful mating? Weather in West Country and weather for next few days is mild, but cloudy with showers, so not great conditions for it.
3. This colony has a super on. Do I need to clear it and remove before treating?

Thanks so much in advance.
T

 

[domino]

Have you checked the mite levels?

 

[SireeDubs]

Have you checked the mite levels?

Have got tray in to have a look (and will use the Beebase varroa calculator to assess). Only want to treat if necessary, and so after some opinions in advance.

Thanks,
T

 

[jenkinsbrynmair]

No harm in doing a single vape - personally I would wait until the queen was mated though.

 

[fatshark]

I've treated a cast (vaporisation) with a virgin and she got out to successfully mate (and returned etc). I'd definitely remove the super after clearing it ... firstly, you want to get as many bees as possible with the vapour (though it's not clear this is how you plan to administer the OA) which will be better in a single box and secondly, despite honey having significant levels of oxalic acid, I'd definitely want to avoid adding more.

 

[SireeDubs]

Thanks for advice all. Just checked tray. It's been in 3 days and I can see just one mite so far, so hopefully no treatment needed yet...

Always useful to have the info though.

 

[jenkinsbrynmair]

I've treated a cast (vaporisation) with a virgin and she got out to successfully mate (and returned etc). I'd definitely remove the super after clearing it ... firstly, you want to get as many bees as possible with the vapour (though it's not clear this is how you plan to administer the OA) which will be better in a single box and secondly, despite honey having significant levels of oxalic acid, I'd definitely want to avoid adding more.

Must have read in something which wasn't there
vaping is safer than trickling (which can effect the queen). as for super/space - not really an issue as it's not vapour it's sublimation which will reach in every corner regardless of hive size (LASI tests have shown this) and it's the fine OA dust which settles after the OA desublimates which does the trick and as it's covering every surface and bee will work for days after so even bees not in the hive at the time of sublimation will get a dose of it.

 

[fatshark]

Not worried about tainting the honey? To my knowledge the amount of OA remaining in honey has only been measured after trickling.

 

[jenkinsbrynmair]

Not worried about tainting the honey? To my knowledge the amount of OA remaining in honey has only been measured after trickling.

I was more alluding to the statement

. firstly, you want to get as many bees as possible with the vapour ....... which will be better in a single box

LASI findings indicate that 2.25 grams will give 95% mite mortality whatever size hive you have.

 

[SireeDubs]

How long would you leave supers off a colony after an OA treatment? Is it the same whether trickle or vaporisation... Assuming the drop is most considerable in first week, then would it be safe to replace or sooner?