Education required

[GaryH]

Mites on boards isn't a great indication of any infestation, ants and other insects can remove mites.
Deciding not to treat ideally needs a better method of checking for which a T cup full (approx. 300 bees ) from brood combs rolled with a T spoon or two of icing sugar will give a better indication, after gently rolling the bees in the icing sugar for a couple of mins simply let them out to fly back and rejoin the colony.
Dissolve the remaining icing sugar with water and count mites , less then three and one can go the non treatment route but will have to esp in the warmer months (April - Sept) carry out monthly sugar rolls to monitor mite levels. 3% or less then one may be ok without treatment if monitored.
Many promote TF and most likely without checking or knowing the real mite loading , most claim their bees cope with TF and wrongly assume they don't even have mites in some cases. The issue though is the unknown virus loading on the bees and stress burden that the bees may be under.

Did you find any more ejected larvae? Would help to ID whether they were damaged by varroa or not. If you had checked brood in the last 6 weeks you may have found advanced pupae with chewed heads, indicative of attempts by bees to remove the diseased.

I'm sure you wanted the original event to be an ordinary drone eviction, but risk to the colony of the alternative is too great, so vaping is a good decision. Let us know the daily drop numbers.

Nothing on the concrete outside the hive today

How long had you kept that board in? I agree, a decent photo would be better and less debris, perhaps on a lighter coloured board. However I saw a mite towards end of clip

board been in for several weeks

 

[GaryH]

Mite drop on white bb 72 hours after Oxalic Acid Sublimation
Is this expected??

 

[Erichalfbee]

Did you check the 24 hour drop?
If they are broodless I wouldn’t worry.I suspect they are as I can’t see any brood cappings
If there is brood vape three more times.

 

[GaryH]

Did you check the 24 hour drop?
If they are broodless I wouldn’t worry.I suspect they are as I can’t see any brood cappings
If there is brood vape three more times.

Thanks
The drop at 24 hours was about half the drop on the photo. I cleaned the bb and left it for a further 72 hours. Not scientific I know but I’m flat out building a work shop

 

[Erichalfbee]

It’s the 24 hour drop that’s used to estimate the infestation in the colony in the presence of brood.

 

[GaryH]

It’s the 24 hour drop that’s used to estimate the infestation in the colony in the presence of brood.

I intend to treat again in early December. This ought to catch any mites emerging with the brood if there were any. I’ve not unsealed the hive since September
Thanks very much for your help

 

[drex]

It is a heavy drop and just shows the OA did it's job. Good plan for early December

 

[ericbeaumont]

resonates deeply with me

How can it? You're an electronic machine.

 

[Erichalfbee]

How can it? You're an electronic machine.

Missed that one...sneaky