ongoing varroa fall

[echidna]

Another newbie question...
On 29 Aug I put in a tray of Apiguard. Just a few dry crystals were left after a fortnight and I put a second tray in. I removed that 17 Oct and there was still some gel left, despite me stirring it a few times as per the instructions.
In the time the Apiguard was in, I counted 2373 mites falling! What worries me even more, is that I am still getting significant fall (> 10 per day) even though I expect residual Apiguard can no longer be having an effect.
The hive started as a swarm in late May and the mite fall was very low when I checked it in July, so the population seems to have exploded in late summer.
I had planned to treat mid-winter with trickle oxalic acid, but I'm wondering if I need to do something else now e.g. Apivar. There seem to be too many varroa, but I also don't want to harm the bees with another treatment so soon, especially if they need oxalic acid later when there is minimal/no brood.
Any thoughts gratefully received.

 

[enrico]

I have one hive with varroa still falling. Will treat in winter with no brood present.
E

 

[Swarm]

Apivar is a six week treatment, it will be very late removing strips but a bit like opening for OA drizzle.
OAV is another, less intrusive option at this time of year. I find October weather too unpredictable for temp reliant methods.

 

[Erichalfbee]

I will be doing a mite drop with sublimated oxalic in a few days which will be a month after my autumn treatment finished. If a colony has a high drop it will get another three vapes. Some colonies rob collapsing neighbours and I usually have one to do again.

 

[jenkinsbrynmair]

are you physically counting each mite? or using the NBU varroa drop calculator?
The varroa calculator, as well as being a notoriously inaccurate method of estimating the mite population is based on natural mite mortality, so if used at or near the time treatment has taken place will give a false disproportionately high figure
Good chance a lot of the mites you are seeing are just the ones killed by the Apiguard which are now being cleared out by the bees.

 

[The Poot in Somerset]

I have two still dropping, despite multiple vapes. It would help if the crystals didn't jump out of the pan - a really annoying thing that I haven't found the cure for yet, reducing the effectiveness of the vape.

 

[madasafish]

I have two still dropping, despite multiple vapes. It would help if the crystals didn't jump out of the pan - a really annoying thing that I haven't found the cure for yet, reducing the effectiveness of the vape.

They must be damp. Keep sealed .

 

[deemann1]

I have two still dropping, despite multiple vapes. It would help if the crystals didn't jump out of the pan - a really annoying thing that I haven't found the cure for yet, reducing the effectiveness of the vape.

A few of mine still dropping alot of mites , after the autumn 3 oa vapes , bought some apibioxol to try instead of the oa crystals , there was a big visual difference in the vapour cloud on the latter product alot more vapour for same weight used

 

[The Poot in Somerset]

They must be damp. Keep sealed .

Last time was a new batch from a sealed plastic bag kept in my garage.
I'll ensure they're fully dry next time and see if makes a difference.

 

[Etton]

My OA was damp when delivered, and was in a sealed bag. I will return next time.

 

[echidna]

jenkinsbrynmair - I did count every mite. The total is made up of multiple counts - I didn't have 2000 on the board at once. I have a vaseline-coated correx board and can easily scrape the mites off and re-coat with vaseline between counts.

I thought all oxalic acid treatments were done when there's minimal brood. I'm getting from the replies that vaping can be done now. Is that a case of balancing harm to brood from oxalic acid versus varroa, or is it just that the treatment will be less effective if there a mites unaffected hidden in brood?
Could trickling be used instead of vaping if I haven't got a vapouriser?

Thanks for all the replies so far.

 

[jenkinsbrynmair]

jenkinsbrynmair - I did count every mite. The total is made up of multiple counts - I didn't have 2000 on the board at once. I have a vaseline-coated correx board and can easily scrape the mites off and re-coat with vaseline between counts.

I thought all oxalic acid treatments were done when there's minimal brood. I'm getting from the replies that vaping can be done now. Is that a case of balancing harm to brood from oxalic acid versus varroa, or is it just that the treatment will be less effective if there a mites unaffected hidden in brood?
Could trickling be used instead of vaping if I haven't got a vapouriser?

Thanks for all the replies so far.

Nothing to do with harming brood, sublimated OA doesn't, just that no treatment is effective on varroa in sealed brood which is why trickling is done at a time when there's minimal brood in the hive.
Unlike trickling, it is also safe to give bees multiple doses of sublimated OA, so if there is brood present, a regime of three sublimated doses of OA each five days apart will cover the whole cycle of phoretic varroa and can be more than 90% effective.

 

[Erichalfbee]

If you are vaping in the presence of brood you need to do it three or four times five days apart. You can’t trickle repeatedly.
Put in Apivar and remove it in ten weeks if mites are still a problem but be aware that your winter bees are already compromised

 

[drex]

Sublimated OA does not harm brood but trickled does affect open brood

 

[gmonag]

I have two still dropping, despite multiple vapes. It would help if the crystals didn't jump out of the pan - a really annoying thing that I haven't found the cure for yet, reducing the effectiveness of the vape.

Are you cooling the pan by dunking in water, between hives?

If not, the water in the OA Dihydrate will boil-off too quickly and eject crystals. Also you run the risk of decomposing the OA into Formic Acid rather than just sublimating.

 

[The Poot in Somerset]

Hi Greg,
Yes plunged into water between vapes and dried as best as I can with cloth.

 

[jenkinsbrynmair]

never seen that happen, and I don't wipe the pan dry between vapes.

Neither do I stand close enough to see what's going on in the pan - it's usually tucked away under the floorb with foam packing over the open end anyway.

 

[Survived-til-now]

Another newbie question...
On 29 Aug I put in a tray of Apiguard. I removed that 17 Oct and there was still some gel left,In the time the Apiguard was in, I counted 2373 mites falling! I am still getting significant fall (> 10 per day) even though I expect residual Apiguard can no longer be having an effect.
but I'm wondering if I need to do something else now e.g. Apivar. .

Mite drop during treatment is no guide to anything.
>10 mites per day two weeks after removing the Apiguard indicates that the treatment has not worked or the infestation was very high in the first place.
In any event you do need to treat. If it were warmer I'd use a 7 day MAQ treatment (which does work on sealed brood) but its too cold now.
Apivar (Amitraze) is not temperature dependent but to be effective it needs the bees to be moving over it and passing the active ingredient around the bees. So you may be a bit late now that the bees are clustering. But you have nothing to lose. Note that Apivar is a 10 week treatment (it is only a 6 week treatment if there is no brood) and don't leave it on beyond that or you'll encourage resistance build-up. Make sure you read the instructions that are to be found by peeling back the Green/Yellow label - where it says "open here" at the bottom right corner.
I suggest that next time you aim to get thymol treatment started earlier (mid-August). Did you monitor before treatment? If you get caught out in future you can consider treatment combined with a sugar shake (to remove phoretic bees) and do a shook swarm - but not now!

 

[Erichalfbee]

Mite drop during treatment is no guide to anything.
>10 mites per day two weeks after removing the Apiguard indicates that the treatment has not worked or the infestation was very high in the first place.

A 24 hour drop when there is brood is pretty useful and will tell you whether that infestation is high
Mites can continue to drop if the colony is robbing a collapsing one too
As far as Apivar goes........ in lots of parts of the UK bees are nowhere near clustering and in poly hives they don't cluster much at all till it gets really cold

 

[Poly Hive]

I'm afraid I have seen them pretty much unclustered in poly at minus 10C.

PH