If you haven’t already started your end-of-summer varroa treatments, then you will be thinking about it now.
Here in Southeast England the heatwave ended the nectar flow earlied than usual, so I’m going to get started on the treatments.
First, work out the size of the varroa problem
I don’t routinely treat my colonies with varroacides at this time of year. I usually prefer to first do a mite count in each colony to see if a treatment is needed.
This approach can be risky, because you need a reliable method of obtaining an accurate varroa level. If you get it wrong and underestimate the varroa population – well, you know what can happen, and how devastating it can be.
The most accurate way of measuring varroa levels is actually an alcohol wash BUT this has the drawback of killing the bees that are used for the test.
So this year I chose to use the sugar roll method which also has good accuracy and doesn’t kill the bees.
Equipment needed for a sugar roll
I was inspired to try this method when Paul (my Beehive Jive co-host) gave me a kit from the University of Minnesota, which was put together to promote the sugar roll method that they developed.
It’s a really handy kit in a plastic tub that contains everything you need to do a sugar roll: a scoop to measure the right number of bees for the test (approx. 100 bees), a plastic ‘jar’ with a wire mesh lid to roll the bees in, icing sugar, and the tub itself, to shake the icing sugar and mites into at the end.
Obviously you could assemble the kit yourself very easily.
Simple and effective
The sugar roll is so simple: shake the bees from a brood frame or two into the plastic tub, then fill the scoop with bees and put them into the jar with the lid on. Just make sure that the queen doesn’t end up in there!
Put approx. two tablespoons of icing sugar into the jar, through the mesh, using your hive tool.
Then simply roll and shake the bees in the jar until they are coated with the sugar. Leave the bees in a cool place for a couple of minutes and then . . .
THE FUN PART: shake the icing sugar out of the jar, into the plastic tub. You can literally see the mites shaking out amongst the sugar! Scary but fascinating!
THE SERIOUS PART: count the mites that have shaken out into the tub (I find it easier to do this if I first spray some water into it). If there is brood in the colony when you do the test, you must then
DOUBLE the number of mites that you have counted.
The sugar roll method is essentially telling you how many mites you have per hundred bees. If the result is more than 10-12 mites per colony, you need to take action immediately.
Too many mites – treat immediately
Once you’re done, tip the bees in the jar onto the tops of the frames. They will look slightly dizzy but will be fine!
A win-win method for the bees and the beekeeper
I love this method because it’s simple, clean and almost instant. Just what you need when making the decision about how to manage your colonies at this crucial time of year, when the winter bees will start developing.
In the past I have used the varroa drop method, where you count the mites that drop onto the tray through the open mesh floor. I never felt completely confident about this because often it was difficult to find the mites amongst other debris on the tray, and some colonies seemed to clean the tray, so I had no idea how many mites were there to begin with.
It’s worth noting that the sugar roll is not the same as when you dust the bees with icing sugar to encourage them to groom their mites off. The sugar roll is a different method and an accurate one.
So, thanks to the University of Minnesota for this simple way of getting an accurate varroa reading in just a few minutes, without harming the bees.
It’s been a strange ‘swarming season’ in my apiary this year. Most of my colonies haven’t tried to swarm, and the ones that have have been rather half-hearted about the whole business. One colony started to make queen cells, then changed their minds and tore them all down. I’ve not seen that before in my own bees.
So far I’ve only had to do swarm control manipulations on four colonies, which is no problem at all now that I have my polynuc method so well-rehearsed that I could do it in my sleep!
Every year as the bees begin swarming preparations, I give thanks to whoever invented the polynuc . . .
Polynucs: possibly the most useful thing you can buy
New splits in polynucs with 14×12 ekes and a feeder on top
I started beekeeping just eight years ago but I don’t remember polynucs being a feature of my early learning. Perhaps that’s because many of the books I read as a beginner were written before polynucs came into use.
(If you want to learn about polynucs and polyhives, look online e.g. dave-cushman.net)
At any rate, everything I read advised that you need a spare complete hive for every colony that needs an artificial swarm.
This always worried me, because I didn’t have the cash (or the storage) for so much spare equipment.
Polynucs to the rescue
I needn’t have worried though as I was about to be rescued by a polymer (how poetic!). The polynuc has changed the way I approach swarm control, and many other aspects of my beekeeping.
When a colony starts to produce queen cells for swarming, I just grab an empty polynuc and within 10 minutes the situation is dealt with, with no dramas.
It’s as simple as this:
- Find the queen and put the frame she is on into the polynuc having checked it thoroughly for swarm cells and destroyed them
- Put in two frames of sealed brood that is ready to emerge – check there are no swarm cells on them first (or the bees will swarm just like in a full colony)
- Put in a frame of pollen and stores
- Put in a frame of empty drawn comb if you have one, or a frame of foundation, or just a dummy board
- Shake in a couple of frames of nurse bees from the main colony (to ensure there are enough bees to take care of the queen and brood)
- Close and move the polynuc straight to where you want it to sit (close to the parent colony if you think you may want to reunite, but you can move it further than three feet – just remember that the number of bees will be depleted by the flying bees returning to the parent hive).
That’s the first stage of the swarm control manipulation; you then need to deal with all the swarm cells in the parent colony as per usual. (My advice is to choose one unsealed cell, not two (always a contentious subject!), and don’t forget to do a second knock-down of queen cells 4 days later.)
Why this works to stop swarming immediately:
- The queen has been removed from the main colony, therefore it will not swarm (bees don’t swarm without a queen)
- The polynuc will not swarm either although the queen is there; obviously you need to keep an eye on it because it will grow rapidly and you may well find queen cells in there in a few week’s time if you don’t give it more space.
- Have your equipment clean and ready, on site. I stack mine up and leave it there
- As soon as you see a primed queen cell, go for it! In my experience this immediate action is crucial to success (I learned very early on that knocking down queen cells is not a method of swarm control!)
- It’s essential that no swarm cells go into the polynuc so check everything carefully. It can be a challenge to find every queen cell and I’ve missed queen cells many times . . .
- Ensure that your queens are marked beforehand, it makes everything faster and easier
- Having some spare brood comb is a real asset – you can get your bees to work on this for you during the active season, removing and storing the drawn comb for use when needed.
What to do with the colony in the polynuc
The new nuc establishes itself quickly. Just watch that they don’t run out of food especially during the ‘June gap’.
You may need the nuc if the new queen in the parent colony doesn’t mate successfully – just reunite the two. However very few of the nucs I make up in this way ever get reunited with the parent colony.
I always like to have a half dozen nucs in my apiary because they are just so useful. I use some of them as ‘factories’ to generate all the components that I need for my small-scale apiary such as drawn comb, frames of brood and bees. You can keep them going throughout the season with a bit of delicate management i.e. don’t take too much at any one time. Obviously you have to give them more space to keep them going like this, and I use the handy extensions that you can get.
Try new things in your beekeeping
One of my ‘factory’ nucs using a polynuc extension
Once I learned all the things I could do with polynucs, I started trying more and more new things in my beekeeping.
If a strong colony is building up very quickly, you can remove a couple of frames of brood and a frame of stores and pollen to make up a nuc (splitting the colony). Do you have a spare queen cell that is too nice to waste? Make up a three frame nuc and let the bees raise her. Do you have a spare unmated queen that has just emerged? You can try introducing her to a nuc and see if she mates.
It was all these little experiments in my own apiary that gave me the confidence to start queen rearing. Now, I’ve learned to use three frame nucs as mating nucs because I find they work better for me than apideas and are more suitable to my small scale beekeeping.
I have even just bought some supers for polynucs. When these first became available I laughed at the idea. But now that I’ve learned a little more about how polynucs can really be put to work, I am converted!
So for me, a polynuc is the way to go when dealing with swarming colonies and I hope they prove useful for you too.
I’ve just come back from a weekend course at the British Beekeepers Association in Warwickshire. I spent two days in the company of two Master Beekeepers, covering the syllabus for the ‘General Husbandry’ exam which – if I decide to do it this year – will put me through my beekeeping paces.
Exam preparation aside, it was great to pick up so many practical tips from the tutors. Simple but essential things like the right way to pick up queens; how to shake combs with queen cells on them (yes, it is possible) and the right way to give a colony a test comb when you suspect it might be queenless. Plus many more nuggets of information that you only get from beekeepers with a life-time of experience.
Right now I am still thinking about our discussions on the subject of oxalic acid. Having been concerned that I left my oxalic acid treatments too late, I was reminded by the tutors that oxalic acid isn’t just for the broodless periods of Christmas and New Year . . .
Why treat with oxalic acid?
Treating colonies for varroa with oxalic acid sublimation is now pretty standard where I live. When I started beekeeping ten years ago, the norm was to do a ‘trickle’ (or spray) treatment directly over the bees in the cluster during the broodless period roughly between Christmas and New Year.
But then the research done by Professor Ratnieks and his team at the Laboratory of Apiculture and Social Insects (LASI) at the University of Sussex demonstrated that it is more effective to sublimate the crystals (vaporise them using heat).
The LASI research said that 2.25g of oxalic acid applied to broodless winter colonies via sublimation killed 97% of the varroa. Furthermore, these colonies then had 20% more brood in spring than those treated via trickle or spraying, or untreated colonies.
Add to this the fact that you don’t need to disturb colonies when you treat with sublimation, and it seems a no-brainer . . .
From the ridiculous to the sublimation
I have a confession: I get put off by the need for extra equipment and by anything that sounds complicated. And at first the need for car batteries, cables etc. put me off trying sublimation. Trickle treatments continued to be the norm in my apiary – and there’s nothing wrong with that, they do work in knocking back varroa levels.
However this year a friend offered to lend me a Sublimox vaporiser. This was an opportunity to try a piece of kit that I couldn’t say no to.
Plenty has been written about this device elsewhere. Suffice to say that it is compact and efficient to work with. You can hold it in one hand. The dose of oxalic acid vaporises when it comes into contact with an integrated heated plate. You simply invert the device and put the ‘spout’ in the hive entrance, and it administers the does quickly and efficiently.
Sublimox ready for use
Using the Sublimox did make the process of treating all my colonies very quick and easy. There was no waiting around for it to heat up. Even I could handle the car battery/power set up. With a long extension cable I could leave the battery and adaptor in my car and run the power down to my apiary without any fuss. It was brilliant.
He’s wearing a safety mask, you just can’t see it in this photo
If you get the opportunity to try this lovely bee toy, be aware that you absolutely must have a proper full-face mask with breathing filter, because when you stand at the hive entrance and administer the vapour, you are bound to come into contact with some of it. This is very important because oxalic acid is highly toxic to humans.
What about the results of the sublimation? I had a hefty mite drop after each treatment, no surprise there. But as I said earlier, I’ve been wondering if it could have been even higher if I’d treated earlier, when there would have been less brood. I assume so.
Oxalic acid: not just for Christmas
Good news . . . oxalic acid treatments are affective at any time the bees are in a broodless state.
This is because oxalic acid acts on the mites that are attached to the adult bees (the mites in the phoretic stage of their lifecycle), rather than the mites in brood. It is thought that the acid burns their mouthparts, causing them to drop off the bees and out of the hive through the open mesh floor.
Phoretic mites on adult bees
So if you’re planning shook swarms, or swarm control that involves separating the queen and flying bees from the brood and nurse bees, it’s a good opportunity to administer another treatment. I think this will make a huge difference to my own management of varroa throughout the year.
A word of caution about using oxalic acid
Interestingly, oxalic acid has been used by beekeepers to reduce varroa levels for years. It is a naturally-occurring organic acid. But that doesn’t mean it isn’t highly dangerous to work with, requiring precautions and care.
Also, unless you use Api-bioxal (see below), the crystals used in sublimation treatments are not an ‘approved medicine’ in the UK for use with honeybees.
This is important to know about, especially if you sell your honey. There is the potential for any treatment to leave a residue in honey or in other hive products intended for human consumption. Obviously there was no honey on my hives at the time of treatment.
Api-Bioxal, is the only oxalic acid-based treatment that has been approved for use in the UK for trickle or sublimation (if you do use a Sublimox be aware that you can’t use Api-Bioxal in it because it has sugar in it, and it will mess up your lovely new toy).
You can of course buy oxalic acid crystals in the di-hydrate form and use those. I did and they are slightly cheaper. But when you buy your di-hydrate oxalic crystals and notice that it says ‘hive cleaner’ on the packaging, it’s because they aren’t approved for use as a varroa treatment and legally can only be sold for cleaning purposes.
For chapter and verse about licenced treatments search the National Bee Unit website for its leaflet on bee medicines.
And for further information about how to prepare oxalic acid, see The Apiarist’s blog.
Ultimately the choice as to how you treat your bees is yours. But don’t let indecision stop you treating your bees per se. In my opinion, anything we can do to keep varroa levels down without resorting to chemicals is a good thing.
So I’ll definitely be sublimating again. I just hope I can borrow that Sublimox. If not, it may be back to trickling for me!
How many times have you been asked by non-beekeepers whether bees hibernate over winter? It’s interesting that it’s such a common question. People are always amazed to learn that the colony doesn’t hibernate or die.
It’s incredible to think that right now, while a winter storm is roaring outside and I’ve turned the heating up, my bees are living in wooden boxes on a freezing field in Surrey!
We all know that our bees have a lot stacked against them in their quest for survival. Although the main preparations for winter are done in autumn, there are things we can do right now to give our bees a helping hand through winter.
Prevent winter starvation
This cluster has starved on the comb
This is one of the most critical threats our bees face over winter. Starvation happens either through running out of stores generally or through isolation starvation (when the cluster loses contact with stores and dies despite close proximity to food).
Starvation often happens in spring, when the colony is growing rapidly. However don’t wait that long to give them some fondant. I heft hives over winter, but it only makes sense if you’ve done it in autumn too and can make the comparison.
Even when I know there are enough stores, I always give them a block of fondant in early January. I put it over the feedhole in the crown board where the cluster can find it in the rising heat. It comforts me to think that if they lose contact with other stores they will probably find the fondant.
I don’t make my own fondant, I buy it. It’s better.
Remember too that its essential to remove the queen excluder in winter so that the cluster can move freely with the queen. If you didn’t do it last autumn, pick a relatively warm day and whip it off. Better late than never.
Take action on varroa during winter
Varroa feeding on larvae
What a nightmare varroa is. I have two colonies that, despite shook swarms, drone brood removal and MAQs, still went into winter with high mite drops. And now the problem requires action.
Oxalic acid is the treatment used at this time of year, now most widely done via sublimation (vaporising the crystals). It’s a good time to do it because there is less brood, so the phoretic mites are more easily knocked down.
Like starvation, varroa is something that you can’t take your eye off. I’ve been measuring the mite drop regularly over winter because I don’t want any nasty surprises in spring – I’ve had that before! Also I’d rather deal with the problem in winter while there is a good opportunity. I’d rather not put varroacides into the growing colony in spring, so better all round to do it now.
The varroa tray is also a very useful way of monitoring where the cluster is, how big it is etc. – the debris on the tray will tell you.
Too much condensation is a common winter problem which can be serious. Caused by the heat of the cluster meeting the cold surface of the hive walls or crownboard, condensation drips on the cluster and can kill a small or weak colony. I find it’s a real problem with polynucs.
The answer is simple: TOP INSULATION, BOTTOM VENTILATION. I haven’t looked back since someone helpfully pointed out that I should stop applying Ted Hooper’s methods to my open mesh floor hives! I once heard a bee inspector describe lack of top insulation as being like leaving the loft hatch open in your house so that all the heat flows out, and the ceilings grow cold.
So I now insulate the crown boards of my wooden hives with those foam quilts (I cut a hole for feeding). Floors are all open mesh for ventilation. No doubt there are other things you can use.
Polynucs get a piece of thick cardboard cut to size and inserted between crown board and roof.
The bees do use condensation in the hive for digesting winter stores but they really don’t need it dripping on them.
Bee poo: is it dysentery or nosema?
What a lovely sight
Bees get dysentery from eating fermented stores. Nosema is an adult bee disease caused by a fungal parasite. Both can show up over winter or in early spring and the visual signs are impossible to miss: squirts of bee poo on the outside of the hive – not just a few, LOTS. It’s obvious that there is a problem! Usually with nosema there’s also bee poo inside the hive, on the combs, simply because the infection gets that bad.
Nosema is diagnosed using a microscope and looks like lots of tiny grains of rice on the slide. In the UK, beekeeping associations often hold nosema clinics in the spring for you to have a sample of your bees tested. This is simple to do and well worthwhile even if you can’t see any visible signs.
There is no licensed treatment for nosema anymore so clean boxes and a comb change are needed in spring, although progress with comb changes tends to be slow because these colonies are weakened. Sometimes re-queening helps with nosema. There’s lots of info online about how to manage this. Check out the Beebase resources at www.nationalbeeunit.com.
Problems with hive or equipment failure during winter
Hives strapped for winter, with mouse guards and woodpecker netting
By this I mean the damp, leaky hive, the collapsed hive stand, etc. Hopefully you checked the condition of your hives and strapped them down in autumn. If not, you can still do it now. Sometimes replacing a roof is all that’s needed to fix damp. If hives do topple and they are strapped, your bees will probably be alright. Obviously try not to disturb the bees while you are making any necessary adjustments. I always think that I won’t need a veil when I’m checking hives in winter and the bees always tell me otherwise!
Green woodpeckers, mice and other pests
Continue to check that mouseguards remain firmly on. Strong winds and animals knocking against the hives can cause them to come loose. Boxes can also be knocked out of alignment.
It’s good to protect your hives with netting, even if you think you don’t have green woodpeckers. They can destroy hives and boxes by pecking through to eat the brood. The have a very distinct ‘swooping’ flight pattern which is a giveaway even when you can’t see the bird clearly.
When I went to check my apiary last week there was a woodpecker sitting on top of one of my hives. The first time I have seen one in five years on that site! Off I went to the hardware store for net.
Moving hives in winter
Of course one good thing about winter is that you can move hives within your apiary without recourse to the 3 feet/3 mile rule. But only after there has been a really cold snap for about two weeks and while the bees are still clustered (try not to disturb the cluster).
Those are, to me, the urgent essentials to watch when looking after your winter bees. I think observational skills are even more important in winter, simply because we can’t get inside the hive to take a look. I always take a look at how many dead bees are in the pile at the entrance, what debris is on the varroa tray and note any spots of bee poo on the outside. This takes seconds but helps in maintaining a picture of what might be going on.
Keeping your eye on a few important things can make the difference between survival and colony loss.
Happy winter beekeeping!
Today was day one of the National Honey Show here in Southeast England and it definitely delivered. I arrived early, found a seat in the lecture theatre and pretty much camped out all day. There were some good talks, but for me the highlights were the lectures by experts from the US and Canada.
The day began with a lecture by Tom Seeley. This was the first time that I had heard him speak in person. I should say that he is a hero of mine, not just because he is a truly great ‘bee scientist’, but because he clearly loves bees for the amazing and fascinating creatures that they are and he is brilliant at communicating this to ordinary beekeepers like me – whether through his books or in person. He is inspiring.
The title of his talk was ‘The Bee Colony as a Honey Factory’. This was not a talk about how to harvest more honey! Instead the emphasis was, as it always is with Tom Seeley, about the bees and their behaviour, in this case how they divide and regulate labour for efficient honey production, mobilising more foragers and also more bees to process and store food when there is a nectar flow.
Using video clips he showed us how the bees use dances to recruit help where needed: the waggle dance to recruit more foragers, shaking signals to wake up sleeping bees (yes, bees do sleep!) and tremble dances to recruit more bees to process incoming nectar.
And there are also the beep signals (like head butting with a buzzing squeak!) which bees inflict on waggle dancers to get them to stop, at times when the colony is already working at full capacity and doesn’t need more nectar.
His lecture gave us layer upon layer of insight and no doubt left many of us pondering yet again how a small creatures with tiny brains can gather and manage information within the hive to organise and direct a workforce of thousands.
I feel like I was given a glimpse into the incredible wonders and possibilities of the ‘bee universe’! I know that my bees are capable of mysterious and wonderful things, but to be shown the depth of possibilities was awe-inspiring!
In short, listening to Tom Seeley today was an absolute pleasure. He gave his talk with excellent awareness of his audience and talked about the bees in such a happy and affectionate way that it’s impossible not to feel good just by being there.
There were some other great speakers too:
Ohio-based Kim Flottum gave a light-hearted but very interesting talk about drones, a subject to which we should all pay more attention (and I include myself in that!). He showed us why drones are ‘special in so many ways’.
So often overlooked, they are of course central to the survival of our bees. As well as being a ‘gene transfer mechanism’, they are an important indicator of colony health and nutritional status.
He spoke about the need to make sure that queens mate with drones that are good genetic stock and how he has moved his bee yard close to particular drone congregation areas in order to facilitate this. He advised us to look for a combination of horizon, tree line and open area when seeking to locate our local drone congregation area.
When it comes to managing varroa, he recommended drone brood removal as an effective method of keeping the varroa population down. He has a weekly cycle of adding empty drone combs/foundation and removing sealed drone combs but warned that this must be done on a fastidious timetable before the brood hatches, or else we are just creating ‘varroa incubators’ (this is how he manages honey production hives; drone brood isn’t removed from mating hives obviously).
The last lecture of the day was given by Heather Mattila from Wellesley College. The title was “Hard Working Bees Need Pollen”. Heather’s research has shown how ‘pollen stress’ on larvae affects the performance of adult bees.
When pollen is in short supply, colonies respond by decreasing brood rearing at first, then, as the shortage progresses, by reducing the number of feeding visits that nurse bees make to larvae and by early capping of larvae. When the shortage becomes severe, bees will cannibalise larvae rather than try to feed them.
Bees that have been deprived of pollen as larvae are smaller, lighter and have a shorter life span. Interestingly, they do less foraging and are twice as likely to disappear while foraging. They also have limited hypopharyngeal gland development, and feed larvae less food, less frequently. And their dances are less precise.
A good supply of pollen is vital for the health of our bees, given that it provides almost all of a colony’s nutrients. Pollen that is stored properly in cells in the hive (processed, packed into a cell and sealed with honey) has a relatively stable nutritive value. We should make sure our colonies have plenty of it for overwintering, as pollen substitutes aren’t as good as the real thing.
Each of these speakers is giving further talks at the Honey Show over the next two days, including Tom Seeley, so head on down to Esher for some inspiration.