Mid season varroa treatments

[Neils]

Have a swarm that turned up a while back. Normally I'd treat with OA as a matter of course but for various reasons I couldn't do that.

The varroa levels are starting to concern me, 5 frames of brood and I'm getting 20-30 mites dropping per week. 6-8 times what my full size hive is dropping. At the moment there's no drone brood to double check with but the first signs of DWV were also present today.

I'm considering that I probably need to take some action with this hive sooner rather than later.

OA is obviously out.

They're too small and, I don't believe, not badly infested enough to warrant a shook swarm/OA treatment.

I've swapped over the original foundationless frame they had because they've filled it full of stores and given them another hopefully that they'll draw drone comb on but I wonder if it's worth taking more immediate action. The varroa calculator recommends a months time so culling drones could be an option.

As they're still building up and have no supers I'm considering going with a thymol treatment, at least for two weeks to see what gets knocked down and I know that putting the queen off lay is a risk.

I did contemplate icing sugar but I don't think it has enough of an effect to consider that it will make enough of a difference.

[EmsE]

I know some bee keepers use formic acid for mid season treatments as it will 'get' the varroa in the cells. It is nasty stuff though and thought may need to be given to the effects it may have on the bees that may not be in the best of health if they are showing signs of a virus. I think Eric McArthur has mentioned this in his posts at some point.

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[Neils]

Keep forgetting about formic acid, probably because I've never tried using it.

[gavin]

Good time of year for thymol though. I use a super frame in colonies like that for drone trapping - they are usually comfortable drawing drone underneath and not many other places.

Eric who?!

[Neils]

I've found this year that despite rolling back my foundation-less experiment somewhat that giving them one foundation less frame with or without wires is good for drone brood. when they're mostly foundation-less the drone brood you want is inevitably supporting a big chuck of worker brood.

I was leaning towards thymol, I have a big bottle of the stuff already made up and a couple of hives that can provide donor brood if the queen goes off lay. Never seen that marked queen again in that hive but there continue to be eggs, the mystery of the elusive queen. I can find here in a box that is absolutely packed to rafters with bees, but not in this one seemingly that is only just bigger than a nuc.

[nemphlar]

I've just AS's a hive and as I was going through some drone brood and found lots of varroa, gone for a formic acid treatment for this split, read the msds notes, why are some wary of using it, what am I missing?

[mbc]

It seems quite dependant on outside weather conditions, too cold and the formic isnt very effective and too hot people have reported excessive queen loss.

[Calum]

I've just AS's a hive and as I was going through some drone brood and found lots of varroa, gone for a formic acid treatment for this split, read the msds notes, why are some wary of using it, what am I missing?

you really shouldn't harvest honey from that hive after treating as it will be in the wax & honey where the cells were still open, and if you use 85% in all the cells apparently... (at least in Germany that would fail a honey control check) - same goes for thymol treatment
A treatment with lactic acid 15% (sprayed directly on the bees, works well at temps above 4°C) for swarms is the only treatment I'd venture to at this time of year, plus of course my regular treatment of culling as many drone frames as they'll build for me (two frames added a week apart) and splitting to make new colonies.

[The Drone Ranger]

I've just AS's a hive and as I was going through some drone brood and found lots of varroa, gone for a formic acid treatment for this split, read the msds notes, why are some wary of using it, what am I missing?
Think it's mainly the danger involved in handling it Thymol does a pretty good job and is easier to use safely

[Calum]

Hi the 60%AS is really easy to use.
As said I would only ever use anything now if I was 100% sure I'#d not harvest an ounce of honey from the hive - all these treatments get in the honey!

[nemphlar]

After last years disastrous spring, I've a box of brood foundation and will be spending the year breeding queens and expanding, dont think I'll be getting any honey.
It's 60% i'm using evaporation seems quite consistent. When you say the FA gets in the comb is it persistent or will it clear in time for later supers?

[Calum]

Hi Nemphlar,
in germany they say it will not clear in time. Thats why only biological control methods are recommended.

[mbc]

So evaporating formic acid in a brood box at the end of May/begining of June precludes later harvesting of honey from an unexposed super in August or later ? This seems extreme to me.

[Silvbee]

Hi all,

Just to add my experiences to this thread. Early in the year I saw that one of my hives hadn't responded to winter oxalic acid treatment at all and varroa numbers were still very high with DWV present.

I looked at my options and after no real results from any of the other treatments in the past I decided to ask my vet to order me some Apivar, it was by far the best thing I've done. Varroa drop rates weren't remarkable in the beginning (as you get with an OA treatment) but they were steady and numbers soon built up. After 4 weeks I removed the strips and the hive has been back to normal for a further 4 weeks now. 3 days ago I opened up a frame of drone brood and didn't see a single varroa and no DWV at all in the hive.

It may seem like a bit of a hassle to get but if you know a good vet and you want (in my opinion) an effective non intrusive varroa solution try Apivar.

Cheers

[GRIZZLY]

I agree with beesinthezoo you can safely use Apivar and zap the mites.According to the blurb that is available from the Apivar people,you can use in a flow without affecting the honey at all.Certainly worked for me and John Mellis tells me thats the only treatment he uses.Hardly ever see varroa in my hives these days.The other advantage of Apivar is that it can be left on for up to ten weeks-more than covering two brood cycles and pretty well zapping most if not all of the mites.

[Neils]

Gone with an apiguard tray for now. The mite count was much lower this week and I didn't see as much dwv as last week but I suspect that as the amount of broods going up nicely that a lot of the mites are now in the brood. Going to see what happens in term of mite knockdown over the next two weeks and take it from there.

If enough are knocked down I might then leave it until the end of the season and give them a full 4 week course of thymol then.

I believe apivar is an Amitraz based treatment? I don't know too much about it but from what little I've read at the moment it doesn't appear to linger in wax or honey. What are the chances of resistance building in mites to it?

[mbc]

I believe apivar is an Amitraz based treatment? I don't know too much about it but from what little I've read at the moment it doesn't appear to linger in wax or honey. What are the chances of resistance building in mites to it?

There are already amitraz resistant mites in Pembrokeshire, mites already resistant to fluvalinates find resistance to amitraz quickly, or so I'm told.

[Neils]

Well I checked the hive after a week of apiguard and pretty much nothing, the week I put the apiguard on there were only 5 mites on the tray. I'm a little perplexed by this to be honest, the signs that I could monitor pointed to a fairly heavy varroa load. Lots of mites dropping and DWV evident on the bees themselves. There's only just the beginnings of drone brood so I couldn't check that. Despite the weather the temperature's been high enough for a decent efficacy so I was expecting to see something at least.