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

[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.

[Jon]

I wouldn't worry about the odd bee with DWV as long as there are not hundreds of them.
Apiguard (Thymol) needs a sustained temperature above 15c to be effective.
Nellie, that might have been your problem unless you have a more tropical climate in Bristol

http://www.vita-europe.com/Map_enscript/frmbuilder.php?dateiname=%2Fen%2Fproducts%2Fapigua rd.htm

[Neils]

Yep, temps around here were 12-16 during the daytime when I applied the treatment so it's not like there was still ice hanging off the roof. I wasn't expecting the full efficacy, but 4 mites over two weeks without Apiguard, let alone with, is a level I can deal with. The 15c recommendation is also due in part as the temperature that Vita feel is when the bees become active and will more readily try and clear the gel rather than continuing to cluster and ignore it. As the bees were active in the colony I felt that a degree or two under the recommended would still be enough to indicate a wider problem with the mite drop. I also felt that if it was warm enough in the hive for them to be drawing out Burr comb in the eke, it was warm enough for apiguard to be effective.

[beeanne]

Thanks all. I'm very very relieved about the idea that deformed wing virus on one or two bees isn't anything to panic over - I did spot a grand total of 2 bees with it (so I assume there's more, but that's all I saw) - so don't beleive there are hundreds.

I did fear it wasn't truely warm enough for thymol (apigaurd) to work - I did have the mesh floor blocked up when the thymol was on - well, as blocked as i could arrange anyway. I reckon I'll look at the varroa count at then end of this week (I'm overseas 'til Friday) and consider options then. I'm keen to increase number of colonies rather than having an enormous honey crop so would be prepared to put thymol on this late if necessary.

[gavin]

Mine also had two DWV bees and I saw a live Varroa on one. No panic, the bees are building up and not making drones yet, so the rate of Varroa increase should be much less than the rate of worker bee increase (for now). One thing that worried me about mine was a spotty brood pattern that suggested some problem, possibly too many mites.

I also had some DWV bees this time last year, didn't treat at all, and the problem seemed to go away until later in the summer.

If I was you I'd put Apiguard on again, as by the weekend it should be warm enough for it to work well. The removal of the gel is probably done by bees more than evaporation, but despite that you need relatively high temperatures for the treatment to work. I'd also keep that shallow frame in if the colony is building well. With no drone brood elsewhere, once they seal it you will be removing a high proportion of the mites in the colony. It also gives you a chance to open some and get a direct picture of the extent of your Varroa problem.

Eric is right in that formic will kill mites inside cells, but it comes with some risk to yourself and also to the queen.

G.

[beeanne]

Fantastic - thanks all! I was having visions of impending disaster.
It was suggested that DWV basically meant I must have a very high varroa count. It's good to know that this isn't necessarily the case.
Hopefully I'll get some drone brood soon enough which should further help.
I've read various things re: formic and whilst it does sound like it can work well, it also seems higher-risk than thymol.

[gavin]

Looking ahead you (like me!) will need a decent level of control to hold the numbers down so that by late summer they are not out of control. You want that late summer-early autumn set of bees to be healthy ones, not encumbered by the viruses that mine may have had from last summer's Varroa experiment. Then the idea is that a mid-winter oxalic treatment hits them so hard you'll not see any again until late summer the following year. In theory.

Next time look at the brood pattern - mine were awfy spotty.

Apiguard and drone trapping ought to do that though.

I still don't understand how John McL gets his bees through the winter so well given his tolerance of Varroa.

Enjoy your trip abroad!

G.

[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:


http://www.youtube.com/watch?v=nQ3gbT2LVac

[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 (http://www.highlandbeesupplies.com/)? Evelyn and Neil don't have it on their web site at present, but maybe they'd consider getting stock if you ask.

[drumgerry]

Haven't yet Gavin but I'm likely to be over there for a few poly national brood boxes in the near future so I'll maybe ask.

Gerry

[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.