Deformed wing virus

[beeanne]

My bees seem to have some evidence of deformed wing virus - not lots of bees with it, but it's definitely there. HOWEVER, my varroa count is pretty low - it was at 2 a day at the end of March, which seems like it should be a tolerable level from what I've read. I treated with thymol this spring, despite the low-ish count, and have a super frame in place for drone which I'll remove - they're ignoring it just now though.
The only thing I can think of is that my count at the end of March was off, and it was it too cold for the thymol to work - I removed the second tray on Saturday as it was empty, and figured that if it was empty then it must have been warm enough for it to evaporate therefore must've been OK. I've put a floor insert in yesterday to count varroa again. Is this the right thing to do?
All advice very welcome!

[Eric McArthur]

Hi Anne

Your Varroa is mostly in the brood cells! Treat your bees with 60% formic acid!

Eric

[drumgerry]

Treat your bees with 60% formic acid!
Eric

Where is it possible to get hold of 60% Formic acid Eric?

Thanks

Gerry

[gavin]

I bought some from Thornes many years ago but have never opened it. They don't seem to sell liquid formic now, but they are selling Mite Away II pads.

[gavin]

For anyone wondering what a bee with a heavy infection of DWV looks like:

[drumgerry]

Great video Gavin! Very interesting. Re the Formic/MiteAway it's collection only so a bit of a problem for me.

Gerry

[gavin]

Do you use HBS? Evelyn and Neil don't have it on their web site at present, but maybe they'd consider getting stock if you ask.

[Alvearium]

I don't believe you can rely on the mite fall count with open mesh floors; if there are bees with Deformed Wing Virus that you see there will be many more that you do not see as they try to crawl away from the colony or are removed by the healthy bees. It is likely there are significant varroa mite levels within the colony already. I think it is more reliable to uncap drone brood and if you start seeing 2 or 3 mites in several uncapped cells then there is a real problem!
Alvearium

[Neils]

Something I have been shown recently when looking for DWV is to look for bees head down in cells so you just have a little bee's arse visible showing no obvious sign of coming back out again, if you dig it out you'll frequently find it's suffering with DWV. It was put to me that they're basically hiding as they'll be turfed out the colony if discovered.

[Neils]

The floor insert should be in for the duration if you're applying a thymol treatment. I believe I'm right in saying that the vapour's heavier than air so without the floor in place it pretty much drops right out of the hive with an OMF and no floor in place.

You can leave the super frame in place, when they're ready they'll draw the comb out on the bottom. Is worth keeping an eye on it though, the first comb my bees drew on the super frame was worker cell sized.

I used an apiguard tray in the middle of March, after the first two weeks I'd had a whole 4 mites on the floor tray so I didn't actually bother with the second tray. While I think it was a little too cold for it to be truly effective, all the calculations I have and backed up by the beebase varroa calculator give that amount of mite drop, without Thymol, as basically "nothing to worry about, treat in autumn" and if there was a bigger problem I'd still have expected a much larger drop from the initial treatment.

I'll leave suggestions on DWV to those with more experience than me.