Varroa – feasibility of clearing?

[Kate Atchley]

Varroa has been found in Acharacle, just north of Ardnamurchan, in the midst of a previously Varroa-free area. No idea how it came in here but some 10 colonies and a bunch of nucs are infested or in close proximity.

Some local beekeepers are pressing for the removal of all infested colonies to protect others and prevent the mite spreading. Some beekeepers see little point in clearing out infested bees as early detection is difficult and it may already have spread more widely than is known, as well as to feral colonies.

Bees currently testing as free of Varroa are at distances of 1 mile, 1.5 miles, 4 miles and more from the infested colonies.

Please tell us if you know of areas where they have sought to clear an area of infestation. Did it work? What are the best conditions for success? It is important we have as full and informed a discussion about this locally as possible so for now I prefer to be the messenger and not share my thoughts on this. Your help is much appreciated.

[Dark Bee]

.........................Please tell us if you know of areas where they have sought to clear an area of infestation. Did it work? What are the best conditions for success? It is important we have as full and informed a discussion about this locally as possible so for now I prefer to be the messenger and not share my thoughts on this. Your help is much appreciated.

Varroa was first discovered in Ireland after some helpful gentleman imported an infested colony from the UK. The area effected was in Sligo/Leitrim, the Dept. of Agriculture immediately set out to have every colony of bees, in and remotely near the area destroyed. They were unsuccessful in their attempts to eliminate the parasite and within 6/8 years the whole country was infected, there are many stories of incredibly irresponsible beekeepers moving colonies about during that period. Compensation was paid for the colonies destroyed and this being Ireland, every derelict or discarded hive that could be acquired anywhere, was pressed into service with a frame or two of brood and compensation claimed. The area on paper had the highest density of hives in Europe.
I think you should try, but chances of success are slim.
In the peninsular areas of south west Ireland, local beekeepers made attempts to reduce the risk of spread by not importing bees from outside the area - again no success, except perhaps to slow down the arrival. In one notable incident varroa spread from the eastern boundaries of Kerry to it's western maritime boundary apparently almost overnight.

PS. In the have we/have we not got varroa days here, a jar half filled with alcohol into which a number of bees were placed, was used to check for the mite. It was a good system - it might be something you should consider.
In those days I used to put my bee suit into a zipped bag and let loose with a can of fly spray after being in a varroa area. I was rather taken by Gavins suggestion that bees squashed on a vehicle front could be a source of infection - it is quite plausible, I had never thought of it. Birds and transported potted plants are also believed to spread the mite.
It may be of some slight comfort to realise you can now import AMM queens from o/s the area.

[gavin]

Hi Kate

Sorry to hear that - I know how hard you've tried to keep the area clear.

I think that you are answering your own question. Bees at 1, 1.5, 4 miles from the known site? Those three sites almost definitely have it already, so are you proposing to move all these out of the area too? Then the affected beekeepers manage their colonies at a great distance? By the time you find Varroa in a colony there will be hundreds if not thousands of them, and given that the workers and especially the drones will move around to other colonies and apiaries it is inconceivable that other apiaries do not already have it. Where it is known that Varroa (well, bees from a Varroa-infested area) were moved into an area (often a sale to naive beginner from a trader of some kind), and then the bees and the Varroa died out (I know of several examples) beekeepers and honeybees were extremely scattered. It sounds like in this case there will be sufficient colonies around to sustain the infestation unless you clear the whole of the area from the Mallaig road to the Sound of Mull of all bee colonies.

It doesn't really matter now how the infestation came in. Could have been someone (known to you or unknown) buying/bringing in bees or queens recently. Could have been an older infestation, thought to have been removed but lurking in a feral colony to infest this apiary. Could have been a far-flying drone (40 miles some say, and so I doubt that even Mull has been fully safe since Varroa appeared on the adjacent mainland around Oban). Some have even speculated that dead bees stuck on the front of vehicles could vector mites and be picked up by bees after the sticky stuff (no real evidence that I know).

None of that is important now. You have the mite. Trying to rid the area of it would be painful and probably unsuccessful. Much better to share knowledge on how to deal with it, and keep your guard up about infecting the more isolated areas.

Gavin

[Jon]

I feel for you Kate. That is the worst possible news.
I agree with the previous two posts.
I don't know of a case where varroa has ever been eliminated.

Gerry Coyne wrote an article in the most recent NIHBS magazine about how varroa arrived overnight in Connemara a few years ago when someone who knew no better introduced a colony from Dublin.

This is really unfortunate but from here on your beekeeping has just got a lot more complicated.
varroa can be kept in check under proper management but one thing is for sure, all the let alone beekeepers will lose their bees as there will be no resistance at all in your stock.

This is a perfect illustration of why some of us are so vocal about imports.
Importing bees brought us varroa to these islands in the first place and some day we will likely get small hive beetle, tropilaelaps and a cocktail of new and unknown viruses via the same route.
The UK bee dealers are sourcing queens wherever they can and selling bees to every point of the uk and Ireland.

Google any of them to verify the origin of their queens.

http://www.fragile-planet.co.uk/


Please note that the Buckfast queens we sell may be imported.

Easy Bee

http://www.easybeeproducts.co.uk/bees-queens.html


ORDERS ARE NOW BEING TAKEN. We breed and supply to the trade, Early Imported- Australian Queens - Carnolian Queens- Nucleus- UK Package bees, Brand new Plywood hives of bees, We send them all over the UK.

Paynes bee farm


You are in luck; - as part of "Paynes Bee Farm" we are well rehearsed in both the breeding and importing of Honeybee Colonies, and take pride and care in every order placed. We have been supplying locally bred honeybees and New Zealand bred bees for many years and look forward to helping you.

I believe there are suppliers based in Scotland doing the same.

[Black Comb]

Sorry to hear that Kate.
Your beekeeping just got more complicated.

[The Drone Ranger]

Hi kate

The chances of complete eradication are slim but not impossible
Everybody needs to insert something to check if they have mites apiguard or api life var at this time of year would be suitable
The new MAQS strips are apparently effective and safe with supers on (check that I don't use them)
Everybody needs to be able to recognise varroa when they drop out
Everybody needs to use a varroa screen floor and insert to collect the dead mites
Everybody needs to treat using effective methods and at exactly the same time
Check out this graph of 22 hives I had in 2008
https://docs.google.com/document/d/1-y577u2BGL0i6zBwwnKxfLAHwT0sl3v29seJjfeVMCQ/edit?authkey=CP2F0pIK&authkey=CP2F0pIK
I was and still am surrounded by people who don't treat or treat but using idiot methods like sugar powder
If everyone round here reduced their varroa populations like in the graph at the same time that's virtual eradication
I jump out of my pram every time someone suggests not treating /breeding for resistance etc
Best of luck you can do it but not alone

[drumgerry]

I wonder if it'd be possible to find where the mites originated? Probably not. But if they've been brought in by someone from down south (Scotland or England) it might be worth doing a check for pyrethroid resistance if you're thinking of using Apistan or Bayvarol.

My condolences but I hate to say it - in this society you can pretty much guarantee all of the varroa free areas will eventually get mites. "We" are a selfish bunch.

[gavin]

If everyone round here reduced their varroa populations like in the graph at the same time that's virtual eradication

Let's assume that there are thousands in the hive(s) discovered, and hundreds, maybe thousands in total, in other colonies in the area. How could existing treatments with their 90-98% efficiency remove all mites? I don't think eradication will work unless all the bees in a very wide area, and all their contacts over the last 2-3 yrs, are destroyed.

Sent from my BlackBerry 8520 using Tapatalk

[Kate Atchley]

Sorry to hear that Kate.
Your beekeeping just got more complicated.
I kept bees with Varroa for 14 years and well remember the complications. Treatments have moved on a little in the 4 years since I had to apply them but not dramatically so. Ah well ....

[The Drone Ranger]

Let's assume that there are thousands in the hive(s) discovered, and hundreds, maybe thousands in total, in other colonies in the area. How could existing treatments with their 90-98% efficiency remove all mites? I don't think eradication will work unless all the bees in a very wide area, and all their contacts over the last 2-3 yrs, are destroyed.

Sent from my BlackBerry 8520 using Tapatalk
over first 4 days of treatment 8000 mites dropped over 22 hives
over last 6 days of treatment 7 mites dropped over 22 hives
ie 0.05 mites dropped/day
Or put another way just over one mite /month in the whole apiary
A single treatment might be 90/95% but we don't rely on one treatment
so 100 x 90% becomes 10 x 90% becomes 1

[lindsay s]

Sorry to hear about the varroa Kate.:( We’ve had a few close shaves up here because people intending to bring bees in didn’t know about varroa or that we are free of it. I expected it to arrive here years ago. I now count each varroa free year as a bonus.

[Jon]

It is too late DR.
There will be untreatable ferals and beekeepers who don't treat.
This has all been tried before and it never works.
All you can do is control it and slow down the advance to other areas as much as possible.

[Black Comb]

The "natural drop" method of measuring is not reliable.
Usually only a few before Apiguard etc., hundreds after.

[Kate Atchley]

All your comments are much appreciated ~ thank you so much. This will help to inform our members too. There will be a sharp learning curve for those who meet Varroa for the first time.

[Phil Moss]

Kate
A very sad situation given all you have done.
As you don't know the source, I would recommend you assume they have resistance to Apistan and Bayvarol, and don't use them unless you first test for resistance. You need to start an IPM program ASAP.
I know of one beekeeper who got bees from an infected beekeeper who had really hit them with formic. I have done a sugar roll test, and there has been no mite drop for 2? years, so perhaps it is possible to clear one colony. But with the number already infected, I would say there is little hope of clearing the area.
Phil

[The Drone Ranger]

I agree with Phil they will be resistant to apistan
MAQS strips are new + thymol treatments both are for periods when there is brood-- oxalic in broodless periods or on swarms
there must always have been a boundary zone between varroa infested and non infested
Can you establish a new varroa free zone it might be smaller now
Everyone needs to check by inserting something now like Api var or MAQS to find out where they have got to

[gavin]

It would make sense at this stage to go overboard with treatments to very strongly reduce the mite populations - just to slow any further spread from the site. But as there are other apiaries in the area it will have spread already. Apivar should be good (from the Dumfries vet, reported to be highly effective for now anyway) and Apiguard should be helpful though its efficacy is variable.

(now I'm the slow typist!)

[lindsay s]

Hi Kate what’s the latest news on the arrival of varroa in your area. Has it spread very far over the summer and what treatments are being carried out at the moment?

[Kate Atchley]

Hi Lindsay

A depressing Summer here as far as varroa's concerned. Within Lochaber, varroa has been found in Acharacle, Kilchoan, Strontian, Mallaig and Morar. The first three of these areas are linked by the distribution of colonies by a beekeeper moving away (no idea how his bees became infested) and someone is known to have brought bees into the Morar/Mallaig area, presumably bringing varroa with them. A couple of other areas are believed to have the mite but this has not yet been confirmed by members.

MAQ strips were used on a number of colonies which had tested negative with careful sugar rolling and drone uncapping and, in two of these cases, varroa showed up. Goes to show how hard it can be to identify varroa in the early stages unless the mites are knocked down with a varroacide. Few of our colonies are housed over mesh floors (there's been no need) so monitoring floor debris is not straightforward.

For treatment, some have used MAQS (one queen was killed by the strips, perhaps with insufficient ventilation on a hard floor) and others Apiguard, though it's late to use that after the heather. We'll help everyone treat with oxalic trickling come mid-Winter. None of the mite levels were very high.

Look out for a request for the latest varroa information in The Scottish Beekeeper some time soon. Gavin has kindly agreed to update the map published last year though we still hope the information will be available on BeeBase one of these days.

[The Drone Ranger]

Hi Kate
Sorry to hear about the queen done in by the MAQS -- but as far as I know it's the only treatment that can be applied with supers still on
If you use the oxalic trickle in winter it can remove a high % maybe 95% of mites

The varrox vaporiser can be used twice during winter so that can mean 95% on the first pass and then 95% of the survivors in the second pass

A good treatment program is 2 passes of thymol at about 70% effectiveness each pass in autumn
Then two passes of oxalic vapour in winter
say 1000 mites first drop leaves 300 second drop leaves 90 (it will be more if they are breeding)
Assuming numbers treble before oxalic 270 becomes 27 after first oxalic then 5 mites left after second oxalic
Course if you have a neighbour doesn't bother treating then his mites will be invading your hives next year

[Kate Atchley]

.....Course if you have a neighbour doesn't bother treating then his mites will be invading your hives next year

Yes, the first four years or so are the most tricky.

I learned beekeeping in the London around the 4th year of varroa and again, when I moved back to Scotland, Edinburgh was in about its 4th year of the mite. So in both places it was beginning to settle ... the absconding from neglected or wild colonies had largely happened and head-in-the-sand beekeepers had mostly given up.

So we've a way to go here. I keep bees in 3 places, two of which have not yet been infested but distances suggest that won't last long.

MAQS seems more risky than it says on the packet, especially when mesh floors are not in use, but it's very helpful in half doses for knocking down as-yet-unseen varroa. As you say, Drone Ranger, it is said not to affect the honey.

I'd prefer to go back to using my old formic acid frame-fitted vapourisers which were highly effective but more bother. I know folk don't like us to use acid ... but hey, I still have some so may as well use it up.

[The Drone Ranger]

Yes, the first four years or so are the most tricky.

I learned beekeeping in the London around the 4th year of varroa and again, when I moved back to Scotland, Edinburgh was in about its 4th year of the mite. So in both places it was beginning to settle ... the absconding from neglected or wild colonies had largely happened and head-in-the-sand beekeepers had mostly given up.

So we've a way to go here. I keep bees in 3 places, two of which have not yet been infested but distances suggest that won't last long.

MAQS seems more risky than it says on the packet, especially when mesh floors are not in use, but it's very helpful in half doses for knocking down as-yet-unseen varroa. As you say, Drone Ranger, it is said not to affect the honey.

I'd prefer to go back to using my old formic acid frame-fitted vapourisers which were highly effective but more bother. I know folk don't like us to use acid ... but hey, I still have some so may as well use it up.
Hi Kate
I have been chatting with a fellow beekeeper down South who lost 2 queens this Autumn
He is sure MAQS was the reason
I think it might be safest as a spring treatment rather than the risky Autumn one
I'm another retiree from London who came home again :)
I hope the new Vita hop based treatment is a good one
Your local bees could very vulnerable as they have had no exposure until now
Best of luck Kate rallying the troops and getting them to work together on the varroa problem

[Calum]

Hi
sorry to hear the further spread of Varroa, but take heart, there are countries that have lived with varroa for decades now.
The greatest shame is that feral colonies can not survive longterm as a result. For beekeepers its a hassle dealing with varroa, but you get used to it.
The problem of treatment of colonies at this time of year (imperative for good quality winter bees) in Scotlands climate is a serious one. Is anyone spray treating with lactose acid? Works excellently on a colony so long as it is brood free, over 90% effectiveness if I remember right. Getting them brood free is more work though.

[fatshark]

Calum
In my experience Apiguard treatment often results in colonies being brood free for a significant period in the autumn. I've always assumed that the resulting mite loss more than compensated for the loss of bees going into the winter. Perhaps another way to achieve this more quickly would be, immediately after the honey harvest, to do a shook swarm onto drawn comb and then treat with OA or lactic acid. It's obviously too late for foundation alone. It would take some organisation and you might have to also transfer frames of stores ... however, assuming you take the honey off relatively early (not heather then!) there should be ample time to generate new brood, and almost no interruption to the laying queen.
Has anyone tried this?

[Calum]

Hi
we tried something similar one year, after the harvest all closed brood was removed and the colonies were treated with formic acid.
The closed brood was packed together in a couple of extra colonies, and also treated as soon as everything had emerged - these were then used to make shook swarms.

It did not go badly, but there were losses due to (most probably) reinvasion. Reinvasion cannot be underestimated.
Doing an OA treatment so early would mean that a later OA treatment around December wouldn't be possible (I think you should not treat the same bees twice)?

[The Drone Ranger]

Hi
we tried something similar one year, after the harvest all closed brood was removed and the colonies were treated with formic acid.
The closed brood was packed together in a couple of extra colonies, and also treated as soon as everything had emerged - these were then used to make shook swarms.

It did not go badly, but there were losses due to (most probably) reinvasion. Reinvasion cannot be underestimated.
Doing an OA treatment so early would mean that a later OA treatment around December wouldn't be possible (I think you should not treat the same bees twice)?

You can treat them twice using the Varrox Vaporiser Calum
Not with the trickle treatment though

[Jon]

Is there any solid evidence that treating twice with Oxalic via trickle does harm or is it one of those statements which does the rounds without any science behind it.
I think that might be advice from Fera or similar but it would be nice to see a paper which showed that it shortens the life of the bees treated or has some other adverse effect.

[mbc]

Is there any solid evidence that treating twice with Oxalic via trickle does harm or is it one of those statements which does the rounds without any science behind it.
I think that might be advice from Fera or similar but it would be nice to see a paper which showed that it shortens the life of the bees treated or has some other adverse effect.

There is solid evidence that even a single trickle does harm, there is no doubt about this to my mind, the question is, will a treatment do more harm than good ? and the likelyhood of this being the case increases hugely when considering a second treatment with the stuff.

[Jon]

Is there a peer reviewed study on the matter though?
Most bee treatments do some harm and some good so that in itself is not unusual.
Look at all the threads about MAQS and queens at the moment.

[Pete L]

Hi Jon, here is one oxalic study, if the link works, there are a few more.....

http://www.nand.be/ambrosius/nieuws/oxaalzuurtest.pdf

[EmsE]

It would be handy to know in what period the twice refers to and whether the restriction is based on the effects on the workers or the Queen (safe to say both are affected with each treatment?). I've always assumed it was just once a year and so have been reluctant to treat swarms with OA during the summer so that I can use it during the winter instead. They stay in the garden until after the Autumn treatment when I put them in the apiary with the others, but it would be handy if I could move them straight to the apiary.

[The Drone Ranger]

Hi EmsE
The queen will be the same but the summer bees won't be there in the winter

[EmsE]

Hi EmsE
The queen will be the same but the summer bees won't be there in the winter

Hi DR, the way some colonies have behaved this year I couldn't count on that;) (having the same queen that is)

so if the concern is the affect on the workers / brood of giving the OA twice, then doing the treatment 6 months apart would be fine? The queen could receive about 3 treatments in her lifetime if just treated during winter- could she cope with more?

[gavin]

Hi DR, the way some colonies have behaved this year I couldn't count on that;) (having the same queen that is)

so if the concern is the affect on the workers / brood of giving the OA twice, then doing the treatment 6 months apart would be fine? The queen could receive about 3 treatments in her lifetime if just treated during winter- could she cope with more?

Could be wrong (that caveat always applies to my posts) but I doubt that the queen will be much affected by the oxalic. If it is the mouthparts - or even the insides - of a bee that get affected then workers lapping up oxalic-syrup or cleaning up deposited oxalic will be at risk. The queen walks about and generally gets fed by workers rather than picks it up directly herself (and does no cleaning duties), so any exposure she gets is secondhand and should be at a lower, less dangerous level and more easily repaired (so temporary).

G.

[Jon]

Hi Jon, here is one oxalic study..

That's not a great study Pete as it looks at Oxalic treated bees hatched in an incubator and treated individually with Oxalic and introduced to an observation hive when there is brood present. That is not how Oxalic is used by beekeepers ie, it is used during broodless periods.

Negative effects looked pretty marginal as well.

Even so the final paragraph of the discussion states:


Regardless to the findings of this study, the
advantages of OA as a treatment against the
mite V. destructor
still outweigh the possible
negative consequences to the honeybee colony
and it should remain as one of the main
varroacides

[Pete L]

I treated 54 full colonies five times with oxalic...five days apart, no ill effects at all, but not trickling.

[Calum]

You can treat them twice using the Varrox Vaporiser Calum
Not with the trickle treatment though

Hi
thats (Varrox Vaporiser ) not legally allowed in Germany.
Doesnt stop some people, stops me though.
All treatments are only allowed after the last honey harvest of the year to ensure nothing pollutes the honey.. Its disconcerting for me to read about the treatment timings in use in the UK...

The weather here is not good for any treatment other than 15% Lactic, so I'll be doing that at the end of the month with my main colonies to reduce their varroa load, the rest should make it through to Christmas as they are, Santa will bring them all Oxalic treats....

[The Drone Ranger]

Hi Calum
All the honey is off before any treatments same as yourself
Wonder why the vaporiser is not allowed? That's probably due to the risk of inhaling vapour?
Long leads then stand upwind is the answer to that, but I do have a full filtered face mask with breathing filters rated for all dangerous chemicals :)
I'm a belt and braces man myself

Lots of people follow this treatment pattern which is :-
After the supers are off treat with thymol -- that can be Api life Var Or Apiguard or just thymol crystals or a dissolved thymol in achohol
Then in Winter Oxalic trickle treatment -once
or Oxalic vapourised twice

The MAQS strips recently licensed here are Formic acid and although the manufacturers say it can be used with supers on I think the majority of users would avoid that.

Apistan is still available and if it's used in alternate years may still be fairly effective (haven't had any recent experience with it)
Lactic acid is also available here in a spray bottle but because the hive needs to be gone through spraying both sides of each frame it is used much less

Only Oxalic acid is of much use in low temperatures so the other treatments are generally applied in Autumn when there is still brood and that reduces the effectiveness considerably, so they need to be applied over a long period of around 4 weeks to get the varroa emerging with the brood

I haven't much experience with the Lactic acid although I do have the spray bottle from Thornes
It would seem to be short acting so presumably you are using this in nearly broodless conditions or repeated spraying as the brood emerges ?

I believe you use Formic as a treatment in Germany.
What time of year is that applied ?

[Calum]

Hi
yes I think the vaporisor is not allowed because of the inhalation risk, especially as so many beeks have their hives in Beehouses.
Here form April-August treatments are biological - drone removal and artificial swarms/ brood removal (also for making new colonies-whateve thats called in english)
Autumn (end august-Sept) Formic 60 (or with vet permission 85%) / Thymol in Apiguard or Thymovar and some others linked (http://www.lwg.bayern.de/bienen/info/krankheiten/28880/linkurl_5.pdf)/ brood removal & lactic acid
December Oxalic solution, or lactic acid..