Tag Archives: winter

Oxalic acid (Api Bioxal) preparation

This post updates and replaces one published three years ago (which has now been archived). The registered readership of this site has increased >200% since then and so it will be new to the majority of visitors.

It’s also particularly timely.

I will be treating my own colonies with oxalic acid in the next week or so.

Mites and viruses

Varroa levels in the hive must be controlled for successful overwintering of colonies. If you do not control the mites – and by ‘control’ I mean slaughter 😉 – the viruses they transmit to the overwintering bees will limit the chances of the colony surviving.

The most important virus transmitted by Varroa is deformed wing virus (DWV). At high levels, DWV reduces the lifespan of worker bees.

This is irrelevant in late May – there are huge numbers of workers and they’re only going to live for about 6 weeks anyway.

In contrast, reduced longevity is very significant in the winter where more limited numbers of overwintering bees must survive for months to maintain the colony through to the Spring. If these bees die early (e.g. in weeks, not months), the colony will dwindle to a pathetic little cluster and likely freeze to death on a cold winter night.

Game over. You are now an ex-beekeeper 🙁

To protect the overwintering bees you must reduce mite levels in late summer by applying an appropriate miticide. I’ve discussed this at length previously in When to treat? – the most-read post on this site.

I’d argue that the timing of this late summer treatment is the most important decision about Varroa control that a beekeeper has to make.

However, although the time for that decision is now long-gone, there are still important opportunities for mite control in the coming weeks.

In the bleak midwinter

Miticides are not 100% effective. A proportion of the mites will survive this late summer treatment 1. It’s a percentages game, and the maximum percentage you can hope to kill is 90-95%.

If left unchecked, the surviving mites will replicate in the reducing brood reared between October and the beginning of the following year. That means that your colony will potentially contain more mites in January than it did at the end of the late summer treatment.

Mid September

Late summer mite treatment and no midwinter treatment.

Over several years this is a recipe for disaster. The graph above shows modelled data that indicates the consequences of only treating in late summer. Look at the mite levels (in red, right hand vertical axis) that increase year upon year.

The National Bee Unit states that if mite levels exceed 1000 then immediate treatment is needed to protect the colony. In the modelled data above that’s in the second year 2.

In contrast, here is what happens when you also treat in “midwinter” (I’ll discuss what “midwinter” means shortly).

Two optimal treatments

Two optimal treatments

Mite numbers remain below 1000. This is what you are aiming for.

For the moment ignore the specific timing of the treatment – midwinter, late December etc.

Instead concentrate on the principle that determines when the second treatment should be applied.

During the winter the colony is likely to go through a broodless period 3.

When broodless all the mites in the colony must, by definition, be phoretic.

There’s no brood, so any mites in the colony must be riding around on the backs of workers.

A phoretic mite is an easy mite to kill 4.

A “midwinter” double whammy

A single oxalic acid based treatment applied during the winter broodless period is an ideal way to minimise the mite levels before the start of the following season.

Oxalic acid is easy to administer, relatively inexpensive and well-tolerated by the bees.

The combination – a double whammy – of a late summer treatment with an appropriate miticide and a “midwinter” treatment with oxalic acid should be all that is needed to control mites for the entire season.

However, “midwinter” does not mean midwinter, or shouldn’t.

Historically, winter mite treatments were applied between Christmas and New Year. It’s a convenient time of the year, most beekeepers are on holiday and it’s a good excuse to avoid spending the afternoon scoffing mince pies in front of the TV.

Or with the outlaws inlaws 😉

But by that time of year many colonies will have started brooding again.

With sealed brood, mites have somewhere to hide, so the treatment will be less effective than it might otherwise have been 5.

Why go to all the trouble of treating if it’s going to be less effective than it could be?

The key point is not the timing … it’s the broodlessness of the colony.

If the colony is broodless then it’s an appropriate time to treat. My Fife colonies were broodless this year by mid-October. This is earlier than previous seasons where I usually have waited until the first protracted cold period in the winter – typically the last week in November until the first week in December.

If they remain broodless this week I’ll be treating them. There’s nothing to be gained by waiting.

Oxalic acid (OA) treatment options

In the UK there are several approved oxalic acid-containing treatments. The only one I have experience of is Api-Bioxal, so that’s the only one I’ll discuss.

I also give an overview of the historical method of preparing oxalic acid as it has a bearing on the amount of Api-Bioxal used and will help you (and me) understand the maths.

OA can be delivered by vaporisation (sublimation), or by tricking (dribbling) or spraying a solution of the chemical.

I’ve discussed vaporisation before so won’t rehash things again here.

Trickling has a lot to commend it. It is easy to do, very quick 6 and requires almost no specialised equipment, either for delivery or personal protection (safety).

Trickling is what I always recommend for beginners. It’s what I did for years and is a method I still regularly use.

The process for trickling is very straightforward. You simply trickle a specific strength oxalic acid solution in thin syrup over the bees in the hive.

Beekeepers have used oxalic acid for years as a ‘hive cleaner’, as recommended by the BBKA and a range of other official and semi-official organisations. All that changed when Api-Bioxal was licensed for use by the Veterinary Medicines Directorate (VMD).

Oxalic acid and Api-Bioxal, the same but different

Api-Bioxal is the VMD-approved powdered oxalic acid-containing miticide. It is widely available, relatively inexpensive (when compared to other VMD-approved miticides) and very easy to use.

Spot the difference ...

Spot the difference …

It’s very expensive when compared to oxalic acid purchased in bulk.

Both work equally well as both contain exactly the same active ingredient.

Oxalic acid.

Api-Bioxal has other stuff in it (meaning the oxalic acid content is a fraction below 90% by weight) and these additives make it much less suitable for sublimation. I’ll return to these additives in a minute or two. These additives make the maths a bit more tricky when preparing small volumes at the correct concentration – this is the purpose of this post.

How much and how strong?

To trickle or dribble oxalic acid-containing solutions you’ll need to prepare it at home, store it appropriately and administer it correctly.

I’ve dealt with how to administer OA by trickling previously. This is all about preparation and storage.

The how much is easy.

You’ll need 5ml of oxalic acid-containing solution per seam of bees. In cold weather the colony will be reasonably well clustered and its likely there will be a maximum of no more than 8 or 9 seams of bees, even in a very strong colony.

Hold on … what’s a seam of bees?

Three seams of bees

Looking down on the colony from above, a seam of bees is the row visible between the top bars of the frames.

So, for every hive you need 5ml per seam, perhaps 45ml in total … with an extra 10% to cover inevitable spillages. It’s not that expensive, so don’t risk running out.

And the strength?

The recommended concentration to use oxalic acid at in the UK has – for many years – been 3.2% w/v (weight per volume) in 1:1 syrup. This is less concentrated than is recommended in continental Europe (see comments below on Api-Bioxal).

My advice 7 – as it’s the only concentration I’ve used – is to stick to 3.2%.

Calculators at the ready!

The oxalic acid in Api Bioxal is actually oxalic acid dihydrate. Almost all the powdered oxalic acid you can buy is oxalic acid dihydrate.

The molecular formula of oxalic acid is C2H2O4. This has a molecular weight of 90.03. The dihydrated form of oxalic acid has the formula C2H2O4.2H2O 8 which has a molecular weight of 126.07.

Therefore, in one gram of oxalic acid dihydrate powder (NOT Api Bioxal … I’ll get to Api Bioxal in a minute! Have patience Grasshopper) there is:

90.03/126.07 = 0.714 g of oxalic acid.

Therefore, to make up a 3.2% oxalic acid solution in 1:1 syrup you need to use the following recipe, or scale it up as needed.

  • 100 g tap water
  • 100 g white granulated sugar
  • Mix well
  • 7.5 g of oxalic acid dihydrate

The final volume will be 167 ml i.e. sufficient to treat over 30 seams of bees, or between 3 and 4 strong colonies (including the 10% ‘just in case’).

The final concentration is 3.2% w/v oxalic acid

(7.5 * 0.714)/167 * 100 = 3.2% 9.

Check my maths 😉

Recipe to prepare Api-Bioxal solution for trickling

Warning – the recipe on the side of a packet of Api-Bioxal makes up a much stronger solution of oxalic acid than has historically been used in the UK. Stronger isn’t necessarily better. The recipe provided is 35 g Api-Bioxal to 500 ml of 1:1 syrup. By my calculations this recipe makes sufficient solution at a concentration of 4.4% w/v to treat 11 hives. 

There’s an additional complication when preparing an Api-Bioxal solution for trickling. This is because Api-Bioxal contains two additional ingredients – glucose and powdered silica. These cutting agents account for 11.4% of the weight of the Api-Bioxal. The remaining 88.6% is oxalic acid dihydrate.

Using the same logic as above, 1g of Api-Bioxal therefore contains:

(90.03/126.07) * 0.886 = 0.633 g of oxalic acid.

Therefore, to make up 167 ml of a 3.2% Api-Bioxal solution you need to use the following recipe, or scale up/down appropriately:

  • 100 g tap water
  • 100 g white granulated sugar
  • Mix well
  • 8.46 g of Api-Bioxal

Again, check my maths … you need to add (7.5 / 0.886 = 8.46) grams of Api-Bioxal as only 88.6% of the Api-Bioxal is oxalic acid dihydrate.

Scaling up and down

8.46 g is not straightforward to weigh – though see below – and 167 ml may be too much for the number of hives you have. Here’s a handy table showing the amounts of Api-Bioxal to add to 1:1 syrup to make up the amount required.

Api-Bioxal recipes for 3.2% trickling in 1:1 syrup

The Api-Bioxal powder weights shown in bold represent the three packet sizes that can be purchased.

I don’t indicate the amounts of sugar and water to mix to make the syrup up. I’ll leave that as an exercise for the reader … remember that 100 g of sugar and 100 ml of water make 167 ml of 1:1 (w/v) syrup.

Weighing small amounts of Api-Bioxal

The amount of Api-Bioxal used is important. A few grams here or there matter.

If you are making the mix up for a limited number of hives you will have to weigh just a few grams of Api-Bioxal. You cannot do this on standard digital kitchen scales which work in 5 g increments.

Buy a set of these instead.

Digital scales … perfect for Api-Bioxal (and yeast)

These cost about a tenner and are perfect to weigh out small amounts 10 of Api-Bioxal … or yeast for making pizza dough.

A few words of caution

I don’t want to spoil your fun but please remember to take care when handling or using oxalic acid, either as a powder or when made up as a solution.

Oxalic acid is toxic

  • The lethal dose for humans is reported to be between 15 and 30 g. It causes kidney failure due to precipitation of solid calcium oxalate.
  • Clean up spills of powder or solution immediately.
  • Take care not to inhale the powder.
  • Store in a clearly labelled container out of reach of children.
  • Wear gloves.
  • Do not use containers or utensils you use for food preparation. A well rinsed plastic milk bottle, very clearly labelled, is a good way to store the solution prior to use.

Storage

Storage of oxalic acid syrup at ambient temperatures rapidly results in the acid-mediated breakdown of sugars (particularly fructose) to generate hydroxymethylfurfural (HMF). As this happens the colour of the oxalic acid-containing solution darkens significantly.

This breakdown happens whether you use oxalic acid or Api-Bioxal.

Stored OA solution and colour change

Stored OA solution and colour change …

HMF is toxic to honey bees at high concentrations. Studies from ~40 years ago showed that HMF concentrations below 30 mg/l were safe, but above 150 mg/l were toxic 11.

At 15°C HMF levels in OA solution can reach 150 mg/l in a little over a week. At room temperature this happens much faster, with HMF levels exceeding 150 mg/l in only 2-3 days. In the dark HMF levels build up slightly less quickly … but only slightly 12.

Therefore only make up OA solutions when you need them.

If you must store your oxalic acid-containing syrup for any length of time it should be in the fridge (4°C). Under these conditions HMF levels should remain well below toxic levels for at least one year. However, don’t store it for this long … use it and discard the excess.

Or prepare excess and share it with colleagues in your beekeeping association.

Don’t use discoloured oxalic acid solutions as they’ve been stored incorrectly and may well harm your bees.

Another final few words of caution

I assume you don’t have a fridge dedicated to beekeeping? That being the case please ensure that the bottle containing stored oxalic acid is labelled clearly and kept well out of the reach of children.


Notes

A quick trawl through the Veterinary Medicines Directorate database turns up several oxalic acid-containing solutions for managing Varroa. These include:

  • Oxuvar – approved for trickling or spraying, an aqueous solution of oxalic acid to which you add glucose if you intend to use it for trickling.
  • Oxybee – approved for trickling (and possibly other routes, but the paperwork was a minefield!), contains oxalic acid, glycerol and essential oils and is promoted as having a long shelf life.
  • VarroMed – approved for trickling, contains oxalic acid and formic acid and can be used throughout the year in one way or another.

I’ve not read the documentation provided with these and so don’t know the precise concentration of oxalic acid they contain. It will be listed as an active ingredient. I have not used these products. As with everything else on this site, I only write about methods or products I am familiar with. I therefore cannot comment on their relative efficacy compared to Api-Bioxal, to Apivar or to careful siting of your hives in relation to ley lines … or 5G phone masts.

 

Preparing for winter

The beekeeping season is fast receding into the distance as the first frosts of autumn appear and, finally, the wasp numbers start to diminish. By now colonies should be heavy with stores, either collected by the bees or provided by the beekeeper.

Winter is coming … be prepared

There is relatively little actual beekeeping to be done this late in the year.

Colonies do not need to be disturbed unnecessarily. They certainly don’t require the usual weekly inspection … they’re not going to swarm, you’ve already applied your miticide of choice and fed them with fondant or syrup 1.

Late queen mating

With temperatures during the day in the low to mid-teens (°C) it is still warm enough to open a colony if you need to.

One of the few reasons I’d open a colony in very late September/early October would be to check if a new queen that had emerged at the end of August had successfully mated. If she had, then all is good. She will continue to lay late into the autumn and should produce sufficient winter bees to get the colony through to the following Spring.

When I lived in the Midlands I would regularly get queens successfully mated in early/mid September. It was pretty dependable, and in good years I’d be actively queen rearing through much of August.

Now, back in Scotland, late queen mating is not something I would want to rely on. I’m certain it happens now and again, but only in very exceptional years.

It’s a tough life being a drone in late August … but not for much longer

This year, many of my colonies turfed their drones out a month ago, and queen mating is not going to happen unless there are plenty of drones about.

A quick peek

It takes just minutes to check whether the queen is mated and laying. Although you don’t need to see the queen, it’s worth using just a whiff of smoke so you have the option of searching for her if needed. If you smoke the colony heavily she’ll end up rushing about or buried under a mass of disturbed bees.

Just a whiff …

You will need to remove the feeder (if using syrup) or the queen excluder and fondant block. Place these aside gently and remember that there are likely to be large numbers of bees adhering to the underside, so balance them on the rim of an upturned roof. This is the time you realise the benefit of using framed rigid wire QE when feeding fondant … removing the block on a flexible plastic QE is a right palaver.

The hive should be busy with bees. Gently remove the dummy board and outer frame. This should be full, or in the process of being filled, with stores. There’s no need to shake the bees off. Just stand it aside out of the way.

‘Guesstimate’ the approximate centre of the brood nest, based upon the density of bees in the seams. Gently lever the frames apart a centimetre or so, then release one of the frames adjacent to the gap you’ve created from its neighbours.

Lift the frame and look for sealed brood, open brood and eggs. By knowing the development cycle of workers bees (3E,5L,13P 2) you can determine approximately when the queen started laying 3.

If she started laying …

Snatching victory from the jaws of defeat

… if there are no eggs or larvae by very late September I would assume that the queen had failed to mate.

You need to use your judgement here. If the weather was poor in the first half of September, but excellent since then, it remains a distant possibility that she has only just mated and has yet to start laying.

Look carefully for polished cells where the centre of the broodnest should be.

And cross your fingers.

Polished cells are a sign that the nurse bees are preparing the comb for egg laying. However, in my experience, they do this even if the queen remains unmated, so it is not a reliable sign that all is well.

You therefore need to use your judgement and be realistic.

Miracles do happen, but you can’t depend upon them 4.

If the weather has been consistently poor – windy, low temperatures (for queen mating, which really needs ~18-20°C) or wet – then assume the worst and ‘save’ the colony by uniting it with a nearby strong colony.

A colony without a laying queen in late autumn will not survive the winter in any state that will make it a viable colony the following year 5.

In Scotland, I routinely unite colonies that do not have a laying queen at the end of August. As described in the last couple of weeks, I do my final colony checks with feeding and miticide treatment.

I know the chances of a queen getting successfully mated after that are effectively zero.

Quick uniting – air freshener

If you need to unite two colonies quickly, without the usual week long wait while they gently mingle after stacking them separated by a sheet of newspaper, you can use a few squirts of household air freshener.

  • Open the queenright recipient colony, removing the feeder and carefully placing it aside to avoid crushing bees (see above)
  • Find the unmated/unlaying/uncooperative queen in the broodless box and remove her (permanently I’m afraid)
  • Spray the top of the recipient colony with a a few squirts of air freshener
  • Do the same with the underside of the now queenless broodless colony
  • Stack the latter on top of the recipient colony
  • Add the feeder back, again giving a squirt or two of air freshener at the interface to stop the bees from fighting

The air freshener masks the distinctive pheromone ‘smell’ of the two colonies, allowing the bees to mingle without fighting.

That’s it.

Job done.

Caveat emptor

Like everything else on this site, I only write here from direct experience. I have successfully united quite a few colonies like this, though nothing like the number I’ve united using newspaper 6.

Given time and the choice I’d always use newspaper 7.

But this late in the season you might not have time.

A day after uniting with air freshener you can, if needed, revisit the hive and go through the double brood box to reduce it to a single box for the winter.

Does it matter which air freshener you use?

I have no idea.

I use Glade Citrus Sunny Beat as it was the cheapest I could find at the time I needed it 8.

Securing the queenright overwintering colony

If you consult the COLOSS records for overwintering colony losses they include a small percentage that are lost to ‘natural disasters’. COLOSS record queen failures and things like that separately, and – in an earlier paper – they define natural disasters as:

… rather loosely defined, as the causes can be very different in participating countries, including fire, storm, flooding, vandalism, bears, martens, woodpeckers, falling trees, suffocation from snow and many more.

The small percentage (0.1 – ~5%) lost to natural disasters vary from country to country, and from year to year.

What is notable about several of these natural disasters is that they should be avoidable.

If your colonies are strong and queenright, and if you’ve fed and treated them to give them the best chance of surviving the winter, it makes sense to do what you can to avoid these natural disasters.

The hive

I use a combination of polystyrene and cedar hives. Sometimes I even combine the two together in a single hive. The majority of my poly hives are from Abelo or Swienty which, for reasons explained elsewhere, are compatible with all the woodenware I own.

The apiary in winter ...

The apiary in winter …

I see no difference in the overwintering colony success between poly and cedar hives.

This doesn’t mean there isn’t one.

I’ve only run about 20 colonies for the last decade. That’s ~200 overwintered colonies. If there were wildly different survival rates I would have noticed. Since I haven’t noticed it either means there is no difference or there is a subtle difference but my sample size is too low 9.

All my colonies overwinter on open mesh floors, usually with the Varroa tray removed. The hives in the photo above are being monitored for mite drop in early December following oxalic acid treatment.

DIY insulation over a perspex crownboard

In addition, all of my hives have a 50 mm thick block of Kingspan under the roof, integrated into the roof, or integrated into the crownboard. In the bee shed my hives have no roof, and are just capped with a block of Kingspan over the crownboard.

Look, no roof … but insulation present all year round

Make sure the stack of boxes in the hive are stable and secure. If the apiary is exposed, strap everything together securely. A colony might survive a week or two of summer showers with no roof, but will surely perish if exposed for any length of time to cold, wet winter weather.

Apiary security

It is unlikely that you will visit the apiary much in the winter. Once a fortnight is more than enough.

It might therefore be worth considering whether it is sufficiently secure from the attention of unwanted human visitors. Unfortunately, incidents of vandalism occur throughout the season, but a hive kicked over in midwinter has less chance of being detected quickly.

Or of surviving.

Although it should probably be included within the ‘Varmints’ section below, large animals – cows, deer, elk, bear, rhino, kangaroo 10 – might also inadvertently, or deliberately, overturn a hive.

Apiary gate

Safe and secure

Fences, either a couple of strands of barbed wire, an electric fence or a full-blown razor-wire topped security barrier, are usually sufficient to keep large two and four-legged visitors at bay.

COLOSS mention both falling trees and flooding as natural disasters.

Winter storms can and do wreak havoc in some years, though I always associate the summer with storm-toppled trees because they’re in full leaf and therefore offer more resistance. It’s certainly worth looking to see if trees adjacent to your apiary might threaten the hives.

Where did Noah keep his bees? In his Ark hive.

Where did Noah keep his bees? In his Ark hive.

Flooding appears to be on the increase. I have experienced minor flooding in one of my apiaries. None of the hives were threatened, but it made access inconvenient for weeks at a time. Again, it’s worth imagining the worst and preparing for it.

Hives often float, but not necessarily the right way up 🙁

Varmints

Having dealt with the threat of large animals 11 it’s also worth considering the damage some small animals can do to hives.

The two main culprits are woodpeckers and mice. Both can be a menace once the frosts set in, but rarely before that.

Woodpeckers, and specifically green woodpeckers (yaffles 12), can learn that beehives contain a wonderful bounty of pupae and larvae. It is learned behaviour. Some green woodpeckers never go near hives, others routinely target them.

In Warwickshire, hives needed to be protected from yaffles. Here in Fife the bird is very much less common and I’ve never had any hives targeted.

Wrapped for winter

Wrapped for winter …

Protection is straightforward. If needed, I simply wrap the hives in a single sheet of DPM (damp proof membrane), pinned in place with drawing pins. The bird need to cling onto the vertical side of the hive to easily burrow through to the brood. The DPM stops them doing this. Leaving bits of the roof or sides of the floor exposed is therefore not a problem 13.

Pixie or Dixie?

Pixie or Dixie?

Mice access hives through overly large entrances. I only have problems with the stupidly cavernous maw of my preferred Everynuc. Mice eat pollen and stores, destroy the brood and wee everywhere 🙁  Thoroughly unpleasant.

Everynuc entrance

Open wide …

A standard mouseguard pinned in place throughout the coldest months of the winter prevents them accessing the hive. Alternatively, on a full-sized colony, the kewl-style underfloor entrances are very effective at excluding rodents.

Kewl open mesh floor showing L-shaped entrance slot

Kewl floor entrance …

That’s not the end of winter-related tasks, but it’s just about all you need to do for your colonies before winter proper starts.

There are some midwinter checks that are needed, but we’ll deal with them nearer the time.


Note

We also have pine martens at one of my apiaries. They are reported to vandalise hives and steal honey (and presumably brood) in late winter. Pine martens are incredibly agile and no fence exists that could keep them out. Time will tell whether they are a problem.

In the meantime, here’s one living up to its name, stealing a pine offcut used to slow down the rate at which they empty the squirrel feeder of peanuts 🙂

2018 in retrospect

How was 2018 for you?

It was a good year here in Fife, with more of everything; more snow, more colonies, more honey (much more honey 🙂 ), more sheds, more wasps, more swarms and more dead Varroa.

Actually, the ‘more dead mites’ isn’t quite correct but I’ll return to that later.

The Beast from the East

There’s not much to say about the winter, but as we moved from February into March Storm Emma (also called the Beast from the East) arrived. The wind whipped the snow across the Howe of Fife (the largely flat centre of the county), dumping large drifts whenever it eddied over hedges or buildings. I had to dig us out of the house and the road from the village was impassable for 2-3 days.

The Beast from the East ...

The Beast from the East …

The colonies were all snug, if not warm, and weathered the storm without mishap. The reality is that if colonies are properly prepared for winter there’s almost nothing to do – or nothing you can do – until the weather picks up again in the Spring.

During the early part of the year I finished preparing our new bee shed. The bees were installed at the very end of March, soon followed by installation of a solar lighting system.

As I write this (early December 2018) the old apiary site has recently been bulldozed flat to make way for a new road. The contractors felled most of the beautiful trees in the well-established arboretum that surrounded the apiary.

All that’s left now is a muddy, ugly scar across the landscape waiting to be tarmac’d. Every time I drive past the line from The Last Resort by The Eagles, Some rich men come and raped the land”, comes to mind.

That’s progress 🙁

On a slightly brighter note, we did save the original shed and it’s recently been reassembled on the new apiary site. This will provide some much needed storage space. The new shed is bigger, but still a bit cramped when used for storage, work and bees.

In like a lion, out like a lamb

Well, almost. March continued cold but the weather had picked up by mid-April. I’d lost just two colonies in the winter, both due to failed queens. By the third week of April I’d started inspections 1 and colonies were all looking pretty good.

The weather got better and better, the oil seed rape (OSR) flowered and the bees started hammering it. Only one of my apiaries had OSR in range and they did really well.

Capped honey super frame ...

Capped honey super frame …

By the middle of June the OSR was over and the honey was all extracted. The high glucose content of OSR nectar means it crystallises fast and very hard. It needs to be extracted before this happens in the frames. Some find OSR honey rather bland or an acquired taste. However, I’ve just processed the first couple of buckets into soft set honey and it’s excellent on toast.

The June gap

In terms of beekeeping it was non-stop. June was frantically busy. Even before the the Spring honey was off the crowded colonies had started to make preparations for swarming.

Just as the bees were preparing to move house I was also busy moving into a new house. It was manic. As fast as I put split boards into colonies more queen cells would appear. I started to run out of frames and brood boxes. I managed to hold some colonies back by slicing out great slabs of drone comb. This takes just a few seconds using foundationless frames and gives the bees something to do rather than make swarm preparations.

And in between all this I was interminably packing, driving and unpacking rental vans doing my own move.

I know I lost a couple of swarms – from about 20 colonies in total 2 – which left me feeling a bit guilty. At least they left with very low Varroa levels so, for a time at least, they would not contribute to the mite levels in the local environment. To ‘compensate’ for colonies that might establish themselves somewhere unwanted I donned my beesuit and destroyed a huge wasps nest in a neighbours roof space.

I also gratefully received a good-sized swarm in a bait hive.

The ‘June gap’ refers to the dearth of nectar that often occurs at this time of year. This year – despite excellent weather – was no exception. I didn’t feed colonies but many around me did. A few were a bit light but were OK until the summer flow started … which it did in late June or early July.

The flow must go on

Lime, blackberry, clover, rosebay willow herb and goodness knows what else. It was excellent. Coupled with continued good weather, hives got taller and taller as more supers were added. I ran out of supers altogether.

With lots of nectar and great weather for inspections it was my best beekeeping year since I moved back to Scotland.

Laden foragers returning ...

Laden foragers returning …

The good weather also aided queen mating which helped with requeening and preparing nucs for overwintering. About 75% of my colonies were requeened this year, almost all through splits of one type of another.

And then it was all over

The flow eventually stopped and the extraction was interminable. Not that I’m complaining. Super after super after super looked like this:

Ready to extract

Ready to extract …

Wasps were a big problem in late summer. I lost a queenless colony and a nuc to the stripey blighters. Amazingly I managed to save the queen from the nuc 3 and she’s now heading a strong colony through the winter.

After a fortnight or so tidying, stock-taking (uniting colonies, cleaning cleared supers, making up a few additional nucs) and ‘final’ inspections it was time to start Varroa treatment and feeding colonies up for winter.

I’ve deliberately finished the season with fewer colonies than I started, but with more overwintering nucleus colonies for sale or making up losses. The absence of a work/life balance means I want to reduce my personal colony numbers by about a third for the next couple of years (to ~10), with another 6-8 overwintering for work. I’ll still be busy 🙁

Mite news

Mite levels have been extraordinarily low this season. For work we uncapped many hundreds to low thousands of individual pupae 4 and found no more than half a dozen mites all season. We’ve seen no evidence of DWV symptoms and irregular mite counts on the Varroa trays have yielded very low numbers.

All colonies were treated by sublimation with an oxalic acid-containing treatment in early September, with three applications at five day intervals. The mite drop was so low (<200 from eight colonies in total in one apiary) that I was concerned that the treatment had failed. I therefore followed it up with Apivar strips in half the colonies. One or two additional dead mites appeared, but that was all.

So, not more dead Varroa, but probably a much greater proportion of the mite population were killed.

The Apiarist in 2018

This is the 300th post over the last five years. Yes, I’m surprised as well. I missed only one Friday when my hosting service was either not hosting or not providing a service 🙁

A few weeks ago I moved the site to a cloud-based virtual server (Amazon LightSail) which, to me at least 5 appears faster and more stable. Processor load is 10% what it was and page response times seem much better. Tell me if it isn’t.

Unique visitor numbers and page reads continue to increase year on year with both up ~33% on last year. What is particularly reassuring is that articles I’ve written on disease management now feature as the most read over the course of the year (though several were written in previous years). The ‘top five’ are:

  1. When to treat? – the importance of correctly timing the early autumn Varroa treatment.
  2. Feeding fondant – quicker, easier and possibly better for the bees.
  3. Oxalic acid preparation – making Api-Bioxal solution properly for trickle treating.
  4. Vertical splits and making increase – manipulations for swarm control and expansion.
  5. Making soft set honey – making all that OSR honey look good and sell well.
"When to treat" monthly page views

“When to treat” monthly page views (5/2/16 to 13/12/18)

The composite page on ‘Equipment‘ also featured amongst this top five, but takes visitors off to all sorts of articles on bee sheds, DIY and hive reviews.

And the future …

This post is already too long. I’ve just checked and see I have 55 posts with working titles and scrawled notes in my drafts folder 6. That suggests there’s likely to be something written next year.

Until then … Happy New Year 


 

Convenience or laziness?

It’s cold and dark and all is quiet in the apiary. Hives appear somnolent. Colonies are clustered 1 and, other than the odd corpse or two on the landing board, I’ve not seen a bee for at least a fortnight.

The apiary in winter ...

The apiary in winter …

Based upon previous experience I suspect colonies are – or very soon will be – broodless. I usually reckon that the first extended (2-3 weeks) period of cold weather 2 in the winter is the most likely time for the colony to be broodless.

In 2016/17 this was the first week in December.

In 2017/18 it was just a day or two later.

In both instances, when the hives were checked, they had no brood.

What’s all this about being broodless?

If a colony is broodless there are no capped cells in which the Varroa mite can ‘hide’. As a consequence it’s an ideal time to apply a miticide like a trickled solution of Api-Bioxal 3.

There are very good reasons why a midwinter OA treatment is necessary, particularly if you treated early enough in the autumn to protect the overwintering workers from the ravages of Deformed Wing Virus (DWV). High DWV levels reduce the lifespan of bees and contribute to many (possibly most) winter colony losses. I’ve even suggested here that “isolation starvation” might actually be due to Varroa-transmitted viral disease.

Time of treatment and mite numbers

Time of treatment and mite numbers

Early autumn treatment protects the winter bees but also leaves the long autumn for the residual mites to continue replicating.

And there will be residual mites. No treatment is 100% effective.

So, paradoxically, if you treated early enough in the autumn to really help protect the winter bees, your mite levels will be higher at the end of the year.

Which also means they’ll be higher at the beginning of next year.

Not a good start to the 2019 season 🙁

Convenience or laziness?

Many beekeepers, for convenience, laziness or historical precedent, choose to apply the winter OA treatment between Christmas and New Year. I suspect that this is often too late. If the queen starts laying again around the winter solstice there will be sealed brood – and therefore unreachable Varroa – by the end of the month.

I’d prefer to have a cold and damp afternoon in the apiary slaughtering Varroa now than the convenience of treating them less effectively during the Christmas holiday period.

The latter might be more convenient … the office will be closed, I’ll be replete with turkey and sprouts and it will be a good excuse to ‘escape’ visiting relatives and yet more mince pies 4.

But is it the best time for your bees?

We have the technology

We have a couple of hives with Arnia hive monitors fitted 5. These have a temperature probe inserted into the brood nest. Brood rearing temperature is around 34°C. Here is a trace of one colony over the last month.

Arnia hive monitor temperature

Arnia hive monitor temperature

The colony temperature was pretty stable (around 33-35°C) until about the 19th of November and has dropped about 10°C since then. Although I’ve not opened the colony I think that this is additional evidence that the colony is broodless 6.

Beekeeping by numbers

Keeping bees properly involves being aware of the seasons, the available forage and the state of the colony. This varies from month to month and year to year 7.

You can’t mechanically (‘by the numbers’) add supers on the 5th of May and harvest honey on the 15th of June. Sure, it might work some years, but is it the best time to do it?

Similarly, you can’t optimally treat a colony for Varroa on the 30th of December unless the climatic conditions and state of the colony coincide to make that the best time to treat.

It might be, but I suspect that generally it’s a bit late if there is a brood break.

If you’re going to the trouble of preparing the OA treatment, donning the beesuit and disturbing the colony you might as well do it at the right time for the bees.

I’ll be treating in between the predicted sleet showers and sunny periods this weekend.

Time to treat

Time to treat

Isn’t evolution a wonderful thing? This post started with a working title of Know your enemy” and was on a different topic altogether. I’ll save that for next week.


STOP PRESS

The above was written at the beginning of the week. Now the weekend is closer it’s clear the weather is going to be cold with heavy snow predicted. Unless the forecast is wrong (and how often does that happen?!) I’ll hold off treating until a) it’s over 5°C, and b) the roads are safe.

Survival of the fattest

Winter bees have high levels of vitellogenin, a glycolipoprotein 1, deposited in their fat bodies which act as a food reservoir for the long winter.

These fat winter bees are essential for the successful overwintering of the colony.

Last week I discussed the major points that need attention for overwintering i.e. strong, healthy colonies with ample food in a weathertight hive.

This week I want to explore the relationship between colony strength, health – specifically with regard to Varroa and deformed wing virus (DWV) – and isolation starvation.

Isolation starvation describes the phenomenon where a small colony of tightly clustered honey bees gets isolated from the honey stores laid down in autumn, resulting – typically during protracted cold periods – in the colony starving to death.

Isolation starvation ...

Isolation starvation …

It’s both a pathetic and distressing sight. Bees, with their heads crammed into the bottom of cells searching for food, dying from starvation when literally inches away from capped stores.

Deaths and births

In temperate climates the winter is characterised by low temperatures and little or no forage for the bees. The queen usually stops laying sometime in autumn and starts again around the turn of the year. During the intervening period she may lay intermittently, but generally in limited amounts.

The fat bodied winter bees that are reared in late summer and early autumn are long-lived (about 6 months) and are responsible for getting the colony through the winter. They protect the queen, thermoregulate the hive and they help rear the brood raised in the autumn and through the winter.

In their absence – or if there are just too few of them – the colony will perish.

Winter bees do not all live for 6 months. The usual figure quoted is ~175 days 2. Some live shorter lives, some longer … up to 9 months under certain conditions.

Importantly, in studies I’ve discussed at length previously, high levels of DWV reduces the lifespan of winter bees. We know this because, in Varroa-infested colonies, researchers 3 have shown that the winter bees die off faster 4.

Live fast, die young

Winter bees with high levels of DWV don’t really live fast … but they do die young. In the studies above the average lifespan of winter bees was reduced by 20% in the colonies that died overwinter.

There are a couple of important things to note here. Dainat and colleagues were not looking at bees in the presence or absence of Varroa, or in the presence or absence of high or low levels of DWV. They simply looked at hives that succumbed in the winter or that survived, then measured DWV and Varroa levels. It’s a subtle but important difference. Their surviving colonies still had Varroa and DWV.

From analysis of hives that died or survived, and having marked known numbers of bees in late summer, they could determine the life expectancy of workers – in their surviving colonies it was ~88 days, in those that died it was ~71 days.

Healthy colonies

The gradual death of bees through the winter coupled with the reduced lifespan of winter bees with high levels of DWV explains why colonies need to be strong and healthy.

The following graphs are based upon modelled data 5, but show the influence of colony size and winter bee lifespan.

The first graph – the least important – simply shows the lifespan of bees. The graph plots the number of bees (on the vertical axis) in a population that die at a particular time (on the horizontal axis) after the start of the experiment. The blue bees have a longer average lifespan than the red bees 6.

Lifespan of winter bees

Lifespan of winter bees

In the following graphs remember that the blue bees are healthy, with low levels of Varroa and – consequently – low levels of DWV. The red bees are unhealthy and have high levels of Varroa and DWV.

Using this lifespan data we can look at the influence on the total number of winter bees in a colony (on the vertical axis) over time (horizontal). Imagine that the horizontal axis is the long, dark, wet and cold months of winter. Starting in early September and running through until late March.

Brrrr 🙁

Winter bee numbers in healthy (blue) and unhealthy (red) colonies

Winter bee numbers in healthy (blue) and unhealthy (red) colonies

It is clear, and of course entirely predictable, that the numbers of bees in the healthy (blue) colony are higher than those in the unhealthy colony at each time point. If the average lifespan is reduced (by disease) more bees will have died by a particular time point when compared with a healthy colony at the same timepoint.

Finally, consider that the shaded section of the graph represents the lower limit of bee numbers for viability. If the number of bees in the colony drops into this region the colony will perish.

Simplistically – and in reality – starting with similar numbers of bees a healthy colony will survive longer than an unhealthy colony.

Strong colonies

Using a similar approach we can also look at the influence of the average lifespan of winter bees on the survival of strong or weak colonies.

The following graph shows the numbers of bees in the colony over time for a strong colony (solid line) and a weak colony (dashed line) where worker bee lifespan is identical 7.

Winter bee numbers in strong and weak colonies.

Winter bee numbers in large (strong) and small (weak) colonies with the same average lifespan.

The shaded section of the graph again represents colony oblivion.

Large (strong) colonies take longer to drop below the threshold for viability and so – all other things being equal – will survive longer 8.

Mix’n’match

A strong colony with high levels of Varroa and DWV might actually survive less well than a weak but healthy colony.

Strong unhealthy colonies might survive less well than weak healthy colonies.

Large unhealthy colonies might survive less well than small healthy colonies.

In this graph the weak but healthy colony drops below the ‘viability threshold’ after the strong but unhealthy colony 9.

Winter bees and brood rearing

This is modelled data, but it makes the point clearly. Large and/or healthy colonies retain more of the all-important winter bees and so survive longer.

Simples.

The differences might not appear marked. However, for convenience 10 I’ve omitted the influence of winter bee numbers on the ability of the colony to rear brood.

If there are more winter bees, the colony is able to thermoregulate the hive better. It’s therefore able to keep any brood present warm. It’s therefore able to rear more brood.

As a consequence, the differences in bee numbers between the large or small, or the healthy and unhealthy, colonies will be much more striking.

Critically 11 the strength of the colony coming out of the winter is often the rate-limiting determinant for spring build-up to exploit early season nectar flows. Weak colonies develop less well.

Isolation starvation

Finally, returning to that pathetic little cluster of starving bees in the image at the top of the page. What is the relationship between colony health, strength and isolation starvation?

It’s now time to dust off my weak-to-non-existent Powerpoint skills …

Isolation starvation schematic

Isolation starvation schematic

Again, it’s straightforward. A large (strong) overwintering colony (A above) only has to move a short distance to access stores in midwinter. In contrast, a small (weak) overwintering colony has to move much further.

Consequently, small colonies become isolated from their stores during long, cold periods when the colony is clustered.

Prediction

Many beekeepers will be familiar with isolation starvation of overwintering colonies.

Most would explain this in terms of “very cold weather and the cluster was unable to reach its stores”.

Some would explain this in terms of “the colony was far too small to reach the stores when clustered”.

Very few would explain this in terms of “the Varroa and DWV levels were too high because of poor disease management last autumn. Inevitably most of my winter bees died off early in the winter, leaving a very small cluster of bees that were unable to reach the stores..

I suspect the real cause of isolation starvation is probably disease … specifically poor management of Varroa levels and consequently high levels of DWV in the colony.


Colophon

Herbert Spencer

Herbert Spencer

Another post, another poor pun in the title. Survival of the fittest encapsulates the Darwinian evolutionary principle that the form of an organism that survives is the one able to leave the most copies of itself in future generations. Darwin didn’t actually use the term until the 5th edition (1869) of his book On the origin of the species. Instead, the phrase was first used by Herbert Spencer in 1864 after reading Darwin’s book. Whilst ‘survival of the fittest’ suggests natural selection, Spencer was also a proponent of the inheritance of acquired characteristics, Lamarckism.

Fondant topups

Perhaps surprisingly if the weather is still very wintery, inside your hives brood rearing has probably started 1. It’s about half way through the winter, there’s no forage available and the colonies are surviving on the stores they laid down in the autumn last year.

But now they have a few more mouths to feed … as a consequence, they’re likely to start using the stores at a higher rate.

I’ve recently written about the importance of hefting hives in the winter to judge (very approximately) how much stores they have remaining. It’s an imprecise science at the best of times, but it is important to ensure they don’t run out.

If they do, the colony will starve to death.

Fondant topups

If the colony is feeling a bit light you need to give it sugar as soon as practical and as close to the clustered bees as possible. The most convenient type of sugar to give is bakers fondant. This is the same stuff you get on Chelsea buns. You can buy fondant in 12.5 kg blocks for about a tenner (in bulk … one-off purchases are likely to be more expensive) from wholesale suppliers.

Fondant keeps well for several years and so it’s worth stockpiling some for emergencies. Since I use fondant for all my autumn feeding as well I buy in bulk (200+ kg) every year or two and stack it somewhere safe, dry and protected from vermin (and other beekeepers 😉 ).

Feeding fondant can be as simple as cutting a thick slice of fondant off the block and laying it across the top bars of the hive. You’ll need an eke or a reversible crownboard to provide the ‘headspace’ over the colony. Replace the roof and any insulation and the colony should be OK … but don’t stop checking for the rest of the winter.

Fondant block ...

Fondant block …

Don’t be stingy and don’t delay

It’s not worth adding a measly few ounces of fondant. If it’s midwinter and the colony is already light, a couple of hundred grams is going to only last a few days.

Don’t be stingy. Add at least a couple of kilograms.

Don’t wait for a balmy midwinter day to add the fondant. Add it as soon as you realise they’re light. It won’t harm the colony to open it up for the few seconds it takes to add the block.

Wear a veil … some colonies can be semi-torpid, others can be quite feisty. How would you feel about having the roof ripped off on a grey midwinter afternoon? You might be trying to save them from starvation, but their reaction might be something a little less than appreciative 😉

Add the fondant as close to the clustered bees as possible. A small cluster cannot move far in very cold weather. Even inches is too much. There are few sights more tragic than a cluster of starved bees just a few centimetres from lashings of sealed stores or a large lump of fondant.

Finally, don’t spend ages clearing bees off the top bars with little puffs of smoke. The colony will be getting chilled and the disturbance will be worse than the loss of the few bees you might inadvertently squash under the fondant block.

Think of the greater good … speaking of which.

Takeaways

When I feed colonies in the autumn I simply slice a complete block of fondant in half with a spade, open it like a book and lay it on top of the colony. With smaller amounts you can use a breadknife to (carefully … mind your fingers!) cut the block up. It’s a lot easier if the block is at room temperature.

For real convenience you can pack plastic food trays with fondant, wrap them in clingfilm and take a couple with you when you visit the apiary. If needed, simply unwrap them and invert them over the top bars of the hive. Large takeaway food containers or one of the many semi-solid types of plastic packaging used by supermarkets are ideal. Tortellini packets are good and just about fit the ekes I’ve built.

Preparing fondant

Preparing fondant …

Wash them thoroughly before use rather than subjecting your bees to last nights Chef’s Special Chow Mein 😉

Finally, remove the clingfilm completely before use. Bees tend to chew through clingfilm and drag it down into the broodnest, even incorporating it into the bits of brace comb they build. Getting rid of the traces of clingfilm during the first spring inspection is a pain, and best avoided.


 

Weighty matters

During irregular midwinter visits to the apiary you need to check if the hive entrances are clear and to determine whether the colony has sufficient stores for the remaining winter. The rate at which stores are used depends upon the number of bees in the colony, the strain of bees, the temperature and whether they’re rearing brood or not.

The apiary in winter ...

The apiary in winter …

The easiest way to ‘guesstimate’ the level of stores is to gently lift the back of the hive an inch or two, and to judge the effort required. Beekeepers call this ‘hefting‘ the hive. Colonies should feel reassuringly heavy. After all, you’re only actually lifting half the weight of the hive – the front remains on the hive stand – and if that feels light it might indicate a problem.

Be gentle

The hive will be full of torpid bees on a freezing cold winter day. On really cold days the wooden floor of the hive might actually be frozen onto the stand. Don’t force it and jar them. And if you can gently lift one side, don’t just drop the hive back onto the stand afterwards. Ideally you want to judge the weight of the colony without the bees being disturbed at all.

Be gentle ...

Be gentle …

However, judging the weight takes experience. Is it a lot less than last week? Is it less than it should be? In the picture at the top there are 5 hives, only two of which (those on the closest stand, and above) are comparable. You can’t easily compare hives if you have only one or if they’re not made of the same material.

But that doesn’t mean you shouldn’t try. Over time you will get experience for what feels OK, and what feels a bit light.

And if any do feel dangerously light then you need to intervene and give them more stores – in the form of fondant – as soon as possible. At least, you need to intervene if you don’t want to risk them starving to death. I’ll discuss topping up the fondant in a future post.

Technology to the rescue

You can get a much better insight into changes in the weight of a colony by, er, weighing it. Luggage weighing scales are widely available, cheap and accurate. With a little ingenuity you can fashion a means of attaching them to the side of the floor. I drilled a 6mm hole through the side runners of the floor and securely tied an eye bolt to some strong polypropylene attached to the scales.

In a similar way to hefting a hive, lift each side carefully, but this time note the weight and add them together. It’s helpful to use scales which automagically record the maximum stable weight. Note the weight down in your hive records and see how it compares over time.

As before, be gentle with these colonies in winter. Don’t go bouncing them up and down. The bees will not appreciate it. With care you can weigh the colony and barely disturb them at all.

What? You want even more accuracy and even less work? Look at the hive monitoring equipment from Arnia, SolutionBee or others. These use under-hive scales hooked up to a mobile phone to upload weights (and lots of other data) for analysis from the comfort of your armchair.

At a price  😯

Frugal bees are better bees

Different strains of bees use their winter stores at different rates. ‘Black bees’ (Apis mellifera mellifera, or Amm) are well known for being frugal. In contrast, some Italian strains chomp through their stores like there’s no tomorrow (and if you don’t feed them, there won’t be).

My Heinz strain 1 of locally-reared bees exhibit variation in the amount of stores they use. The two comparable hives on the same stand in the top picture both started the winter packed with stores. By Christmas one of them remained reassuringly heavy, whereas the other one was feeling light and was given a fondant supplement.

All things being equal, I’d prefer my bees use less rather than more. When the time comes to rear queens later in the season the thrifty colony will be favoured.

Some beekeepers take a harder line than this … if a colony can’t store enough to get it through the winter they let it starve and so allow ‘natural selection’ to operate.

I’d prefer to have the luxury of an additional colony in Spring. I won’t rear queens from it and I’ll minimise drone brood to prevent it contributing to the next generation. Instead, I’ll build it up in the spring and then split it for nucleus colony production in late May or early June.

Unnatural selection perhaps, but it’s a solution I’m comfortable with.

Given the choice, I suspect it’s what the bees would prefer as well 😉

Frosty apiary

Frosty apiary


 

Bring out your dead

It’s midwinter. There’s very little to do in the apiary. Time is probably better spent planning and preparing for the coming season (and drinking tea in the warm).

However, there are a few jobs that shouldn’t be forgotten.

Let the undertakers do their work

The first job is to ensure that the hive entrances are clear. This allows bees to readily exit and re-enter the hive for ‘cleansing’ flights during warmer days. During these days the bees will also remove some of the many corpses that accumulate during the winter. If the hive entrance is clear these can be removed easily. If the entrance is blocked they continue to build up and – on warm days – you can hear a panicky roar of trapped bees from inside the hive.

Corpses at hive entrance ...

Corpses at hive entrance …

Don’t worry about the loss of these bees. It’s what happens. The colony goes into the autumn with perhaps 30,000 adult workers. Four months later, at the end of December, there may be only about one third of this number remaining. Brood rearing is limited during this period (and at times non-existent), but picks up in early January.

Attrition rate

Even assuming no brood rearing, this means that 150-200 bees a day are expiring. If they are rearing brood, even at a significantly diminished rate, it means that more than 200 bees a day are dying.

For comparison, 300 bees is about a ‘cupful’ … the number you’d do a Varroa count on. Imagine dropping a cupful of dead bees on the hive floor every day for a fortnight. Unless these corpses are cleared away the hive entrance gets blocked. This is what the ‘undertakers’ clear.

On calm warm days you can find the corpses littered on the hive roof, or in front of the entrance, dropped there by workers carrying them away from the hive.

Since ‘flying’ days may be infrequent at this time of year and/or bees have other jobs to do, like go on cleansing flights or collect water, they may not carry the corpses very far … don’t be alarmed by the numbers of corpses around the hive entrance.

Don't count the corpses ...

Don’t count the corpses …

A bent piece of wire to the rescue

I mainly use kewl floors with a dogleg entrance slot (see the top image on this page) that reduces robbing by wasps and negates the need for a mouse guard. I’ve fashioned a simple piece of bent wire to keep the entrance slot clear of corpses on my irregular visits to the apiary during this time of the year.

Kewl floor unblocker ...

Kewl floor unblocker …

I’ve only ever had problems with large, double-brood colonies after very extensive cold periods (~4 weeks with hard frosts every night) when the entrance has got blocked. One colony I managed to save despite it showing signs of Nosema after the bees were trapped for several days.

It takes just seconds to check that the entrance is clear and gives considerable peace of mind. If you use mouseguards it’s worth checking the holes aren’t all blocked after an extended cold period.

Next week I’ll discuss the other important winter check … are there enough stores remaining to stop the colony starving?


Colophon

Anyone familiar with Monty Python will recognise the post title.

This was one of the well-known scenes from Monty Python and the Holy Grail, a 1975 film parody about the Arthurian legend and a low-budget quest for the Holy Grail. The film usually ranks close to the top in surveys of the best comedies of all time, with another Monty Python film (The Life of Brian) often topping the tables.

In the film there’s a further scene (A self-perpetuating autocracy) which involves a political argument with interesting parallels between the public perception 1 of a colony of bees and the biological reality. This is topical, with the recent Deloitte report on women in leadership roles holding back the careers of other women they perceive as a threat.

Perhaps a topic for a future article … ?

Queen bees and the self-perpetuating autocracy.

 

2017 in retrospect

The end of the year is a good time to look back at the highs and lows of the season. What worked … what didn’t work … what on earth happened to our weather in June?

Early June 2017 ...

Early June 2017 …

June is an important month here in Fife. Early season colony buildup should be pretty much complete, most colonies will have had some sort of swarm control measures in late May, virgin queens may well be present in many hives, the OSR is over and colonies need to consolidate for the main summer flows.

But instead it just rained.

Rainfall in Fife was 225% the 40 year average, access to apiaries was problematic due to flooding and queens could only get out to mate if they were wearing ‘water wings‘.

Big mistake

Many colonies needed to be, or should have been fed, during June. Mine had reasonable levels of stores as I’d not taken much early season honey. I therefore chose not to feed them. In retrospect I think this was a big mistake.

Although not monitored carefully, I suspect brood rearing slowed, so reducing the colony size to effectively exploit the July/August flows. It was my worst summer honey crop in years.

Lesson one … If this happens next season I’ll continuously feed thin syrup to keep the queen laying strongly.

Doing the splits

Notwithstanding the incessant rain, swarm control – and the inevitable associated queen mating – went pretty well. I generally use splits of one form or another and most queens got out to mate, albeit a little slower than I’d have liked. If swarm control is needed for colonies in the bee shed we can’t do vertical splits (because of the way entrances are organised) and instead just take a nucleus colony away and let them rear a new queen.

Only ‘pretty well’ though because I suspect I lost a cast from a vertical split that went calamitously wrong. I’d left the queenless half far too strong and inadvertently also left multiple developing queen cells.

D’oh!

This wasn’t going to end well  🙁

I did manage to capture and hive another cast from the same colony, but the first virgin queen and well over half the workers were long gone.

So, lesson two (which I’ve been taught many times before 😥 ) is to be decisive when there are multiple queen cells in a split. Either knock them back appropriately (which I’ll explain next year) or split the box up into multiple nucs. Don’t dither. Don’t prevaricate and don’t – as I think I did this year – simply forget to check.

All the gear, some idea

I blatantly poached how to build foundationless frames with bamboo skewers from the internet. I claim zero originality here. It isn’t my idea. However, I’m pleased to say it was a great success. Simple wooden starter strips were also a roaring success. It’s very satisfying when you realise you don’t need to spend £1 per frame on foundation.

Nearly completed ...

Nearly completed …

I’ve used quite a few Abelo poly hives this season. They’re a strident colour – blue and yellow – but reasonably well made. Colonies checked this winter are doing well in them, with bees right up to the side walls on sub-zero days. This suggests to me that they are well insulated.

An Abelo/Swienty hybrid hive ...

An Abelo/Swienty hybrid hive …

There are some aspects of these hives I have yet to be fully convinced by; upper entrances, the crownboard, high condensation levels and a small Varroa tray. I’ll review them more fully when I’ve been using them for at least a full year.

Old invasives …

The bête noire of most beekeepers, the Varroa mite, has featured heavily throughout the year. In print, though thankfully not in my colonies. I’ve tried to emphasise the need to treat appropriately, using the right miticide at the right time. Since most approved (and even some unapproved 😉 ) miticides are all pretty effective, the timing of treatment is probably the most important point.

2016 temperature data and OA treatment ...

2016 temperature data and OA treatment …

In three recent posts I presented the importance of midwinter treatment, how to prepare the oxalic acid-containing miticide and how to administer it. These should probably be read in conjunction with an earlier article on when to treat, which I’ll come back to in a minute. Finally, as far as Varroa is concerned, I discussed potential ways to optimise the timing of the winter treatment by watching the weather. I suspect that most beekeepers treat too late in the winter.

If you have yet to treat this winter … get a move on!

… and new ones

The new invasive that got some coverage was, inevitably, the Asian hornet. Having first arrived in 2016 I think we’ll be subjected to annual incursions until it gets established here. Constant vigilance is going to be needed to help postpone what might be inevitable. Just because it is inevitable doesn’t mean we shouldn’t try and delay it’s permanent arrival.

Devon beekeepers got some first-hand experience of how vigilant you need to be to both spot and photograph Asian hornets in September. Martin Hocking has written about his experience in the Devon Beekeeper (pp172 and also in November’s Bee Craft)  which should be required reading for beekeepers, with a follow up article about his experience in December (see pp196). There’s an open meeting on the 20th of January at Harberton Parish Hall, TQ9 7SD where the threat posed by the Asian hornet – and how to mitigate it – will be discussed.

Although rarely mentioned this year, Small Hive Beetle now appears to be established in the Calabria region of Southern Italy. Data updated in late September and November indicates that positive wild colonies and sentinel nucleus colonies are still being found, indicating that attempts to eradicate the beetle have failed. Infested colony numbers are perhaps a bit lower than previous years, but since there’s no readily-available data on the level of surveillance, it’s not clear whether this shows that control is having an effect, or if people are just not looking as hard.

www.theapiarist.org

Posts have been made every Friday of the year, with a few additional ones when something important happened (Asian hornets or I was ‘advertising’ a Convention I was speaking at … OK, my talk wasn’t important, but the Welsh Beekeepers Convention was 😉 ).

Regular as clockwork ...

Regular as clockwork …

The Friday posts are intentional. It’s when most of us have time to read stuff. The regularity was not and, frankly, it’s a bit of a surprise I’ve achieved it. However, there it is. No promises it’ll continue like that. You can register to receive email notification of new posts in the right hand panel.

Visitor numbers to the site are markedly increased from last year. Page views per visit are down fractionally, but not significantly. It’s clear that more are finding the site as it becomes better indexed by the search engines, and as pages are referenced by other sites.

24 months on www.theapiarist.org ...

24 months on www.theapiarist.org …

My attempts at generating a presence on Facebook was an abject failure. I simply don’t have time to do anything other than automagically post updates from here on Facebook (as I do on Twitter, which I’m a bit more familiar and competent with … follow me on @The_Apiarist). Apologies if you tried to ‘Friend’ me (or whatever) on Facebook. I’ve cancelled all the email updates as I simply couldn’t keep up. Or, when I tried, I didn’t know how to! I belong to the pre-FB generation, or the one before that.

Beekeeping is international, with different problems – but many shared ones – globally. I’m grateful to the visitors from 161 different countries and the European Union 🙂 Less than 50% of the readers are from the UK, despite the UK-centric bias I inevitably exhibit (°C, colour, no mention of queen castles or slatted racks, precious little discussion of Langstroth hives etc.). Southern hemisphere beekeepers don’t even do things at the same time of the year, so many of the posts aren’t even topical for readers in Australia, New Zealand and South America. Whatever, I’m grateful people took the time to visit and read stuff.

And the winner is …

I don’t publish visitor numbers, but I do comment on the popularity of particular pages. For several years a post on my honey warming cabinet has been the most popular. It was originally posted ‘way back’ in 2014. Frankly, it was useful, but not particularly challenging or exciting.

But it’s all change this year. Aside from the homepage, the archive and blog pages, all of which people arrive at to to get the most recent posts, the honey warming cabinet post was a distant fourth in the 2017 rankings.

Above it were posts on vertical splits and making increase, feeding fondant and – particularly pleasingly and top this year – when to treat colonies with miticides against Varroa. I say particularly pleasingly as the When to treat? post is a serious article on an important subject, underpinned by scientific arguments. The timing of the late summer treatment is probably one of the most important events in influencing the health and overwintering success of the colony. This post was almost twice as popular as any other post this year which – because it originally appeared in early 2016 – suggests it is finally being widely cited and accessed by beekeepers.

When to treat?

When to treat? Finally getting read when it should be.

And what does the future offer?

Frankly, as I write this in mid-December with a streaming cold, a box of tissues and slathered in Vicks VapoRub (really, it’s not a pretty sight) I don’t know. I have two priorities at the moment; getting the new bee shed properly setup and (with my researcher hat and lab coat on)  starting studies of Chronic Bee Paralysis Virus. Both will get coverage here.

Bee Shed 2 ... the windows still need some work.

Bee Shed 2 … the windows still need some work …

In terms of the website I’m acutely aware there’s no proper indexing or rational list of articles on particular subjects, perhaps other than Varroa. I hope to bring some order to the chaos, allowing me to not repeat myself, to develop some themes more fully and to not repeat myself 😉 . I also know I have a load of unwritten stuff on queen rearing.

Winter time is also DIY time … dabbling with wood, perspex, Correx and Elastoplasts. Something will surely result from this, in addition to the blood loss and bad language.

If there are things you’d particularly like to read drop me a note. I’m interested in the science underlying beekeeping and have little patience with some of the dogma and That’s the way we’ve always done it stories. I’ve already written about the importance of training and the responsibilities of beekeepers. I’ve got some more on these areas planned as I think they’re too often ignored by beekeepers in the UK.

With Best Wishes for 2018. May your colonies be docile, your supers unliftable, your queens well-mated and your swarms (again) in my bait hives 😉

Happy New Year


 

 

Weather to treat

Not Whether to treat? … to which the answer is yes. Instead, a poor pun on the choice of how I use temperature as an indication of when to treat colonies in midwinter …

Midwinter OA-based treatments

Oxalic acid-based treatments for midwinter Varroa control are most effective when colonies are broodless. This is because oxalic acid (OA) treatments only kill phoretic mites and are ineffective against mites in sealed cells. They are therefore ideal for use on swarms, packages and broodless colonies in midwinter.

Winter in the apiary

These OA treatments include Api-Bioxal, the VMD-approved treatment, and unmodified oxalic acid, it’s active ingredient. The importance of midwinter treatments, the preparation of the OA solution and how to trickle treat have recently been covered. I’ve previously discussed sublimation and will do so again in a longer article in the future.

The beekeepers winter dilemma

How can you tell whether your colonies are broodless in midwinter?

On a warm, sunny, Spring afternoon this takes just a couple of minutes … remove the roof, crack off the crownboard, gently lift out the dummy board and the adjacent frame, look carefully at the mass of bees covering the top bars, aim for about the middle and gently prise apart those two frames, lift out a frame from one side of the ‘gap’ and – Hey presto – brood.

Just writing that in early December makes me hanker for much warmer days …

Memories of midseason

Memories of midseason

Actually, you can do exactly the same in midwinter. There are videos on the internet showing an experienced and (in)famous Finnish beekeeper opening his colonies at -10ºC.

I’ve opened and briefly inspected colonies at low temperatures (though not sub-zero). The bees are usually pretty torpid, reluctant to fly – or simply too cold to – and you can be in and out in just a minute or so. Bees cope pretty well with this. It undoubtedly disturbs them a bit and it breaks the propolis seal on the crownboard, but – done carefully and quickly – it’s the only foolproof way to determine whether a colony is broodless in midwinter.

But what if they’ve got brood and it’s therefore not the optimal time to treat? Do you go back and repeat the entire process in 1-2 weeks? What if it’s snowing next time, or there’s a howling gale blowing?

An alternative approach is needed.

The annual brood rearing cycle

As the colony moves from summer to autumn the egg laying rate of the queen drops. It goes on dropping, although not necessarily smoothly, as the days shorten further, the temperature drops and the sources of pollen and nectar disappear. If the queen stops laying altogether then the colony will become broodless about 21 days later.

At some point, perhaps early in the New Year, the queen starts laying again. Slowly at first, but at increasing levels as the season starts. Once foraging starts in earnest the egg laying rate increases markedly and peaks sometime in June.

The precise timing of all these changes cannot be predicted. It’s likely to be dependent on a range of factors – nectar and pollen availability, the strain of bee, day length (and whether it’s increasing or decreasing) and temperature.

Of these, temperature probably has the greatest influence.

Probablyß.

Generalised annual brood and worker numbers ...

Generalised annual brood and worker numbers …

Here’s a quick’n’dirty graph put together with BEEHAVE showing a generalised annual cycle of total brood (blue) and adult bee (red) numbers. Under the conditions in this model the colony is broodless for ~30 days at the end if the year.

Temperate(ure)

Part of the problem with being definitive about the annual brood cycle is the temperature variation with latitude. Temperate regions stretch – in Europe – from Northern Finland to Southern Spain. Bees are kept throughout this range, but obviously experience wildly different climates.

And then there’s the year to year variation.

So if you can’t predict when the colony is going to be broodless, perhaps you can observe the weather – and in particular the temperature – and make an educated guess.

Watch the weather

Over the last few years I’ve applied my midwinter treatment soon (<6 days) after the end of the first extended cold period of the season. This is generally earlier than most beekeepers, who often treat between Christmas and New Year, or early in January.

So, how do we reasonably accurately monitor the weather for a suitable time to treat?

Ho ho ho

Ho ho ho

Most of us live in centrally-heated splendour, protected from the day-to-variation of temperature by heated car seats, air conditioning, hot water bottles, Thinsulate and wood-burning stoves. Do you know what the temperature was today? Rather than trust the wildly-variable (in accuracy) national weather reports for the actual temperature near my apiaries, I instead use very much more local data from Weather Underground.

There are hundreds of ‘amateur’ weather stations across the country that upload data to wunderground.com. Most of these provide current and historic data, including temperature (max, min and average). Here’s one for Auchtermuchty in Fife (on wunderground.com) and directly from the weather station.

Once the weather cools I keep an eye on the average temperature over an extended period of a fortnight or so. If it remains low I wait a bit more … but I then treat as soon as practical after it warms up to 8-10°C or so.

The proof of the pudding

Here’s a graph of the temperature data for 2016§. As indicated on the graph, I treated colonies on the 7th of December.

2016 temperature data and OA treatment ...

2016 temperature data and OA treatment …

I didn’t open my colonies, but others opened on the same day nearby were all broodless. The 7th was chosen as it was the first warm (relatively!) day after a 19 day window in which the average temperature had barely climbed above 5°C.

These treated colonies went into the New Year with vanishingly low Varroa levels.

And again …

This year appears to be repeating a very similar pattern. We’ve had frosts most nights since the 10th of November. It started to warm up significantly in early December as storm Caroline bore down on Scotland and I treated most of my colonies on the 6th 

… by the light of a head torch, in light rain and strengthening wing at 7pm after work.

No, I didn’t open any of the hives to check if they were broodless  😉

It was over 11°C in the apiary when I treated, the barometer was plummeting and the forecast was for near-zero temperatures within 24 hours and remaining that way for another 10 days.

Some of my hives have perspex crownboards. These allow me to check both the state of the colony and if the vapour from my Sublimox has permeated to every corner of the hive. All the colonies were very loosely clustered, with a few bees even wandering out briefly onto the landing board in the dark as I bumbled around preparing things.

The Varroa trays will now be checked in a week or so to work out the mite infestation levels. In the meantime, I can start planning for the coming season knowing I’ve done the best I can to reduce virus levels in the colonies, so giving them a good start to the year.

A Hi tech solution?

Colonies rearing brood maintain a higher, and stable, broodnest temperature (32-35°C) than colonies without brood. It is therefore possible to determine whether a colony has brood by monitoring the temperature directly, rather than trying to infer it from the ambient temperature.

Brood rearing starts ...

Brood rearing starts …

Arnia make hive monitors that allow this sort of thing to be measured. It would be interesting to relate the brood temperature to the ambient temperature (described above) to determine how accurate or otherwise simply ‘watching the weather’ is. Of course … what you’d really want to do is monitor when brood rearing stops and treat soon after that.

Stop press

I treated colonies in our research apiary the following day – the 7th – with dribbled Api-Bioxal. The temperature had dropped almost 7°C since the previous evening and colonies were again beginning to cluster tightly. Under these conditions I’m never confident that the OA vapour penetrates fully, so prefer to trickle treat.

I briefly checked one strong colony in a poly hive for brood.

It was broodless, as I’d hoped  🙂

Of course, this doesn’t guarantee all the others are also broodless, but it does give me some confidence that I’d chosen the correct weather to treat.


† This article, like most on this site, discuss beekeeping issues relevant to temperate climates. It’s important to make this clear now as most of what follows is irrelevant to readers from warmer regions.

∞ Even if there is brood in midwinter, it’s going to be in pretty small amounts. The rate at which this brood emerges is going to be low. The chances of determining what’s going in the colony by ‘reading the tea leaves’ from the debris falling through the mesh floor of the hive is therefore not great. It would probably also require repeated visits to the apiary.

ß This needs qualifying … in midseason, when the temperature varies but it’s not generally cold, the nectar flow is probably the rate-limiting step for brood rearing. The June gap is regularly associated with the queen shutting up shop for a while. However, in late autumn and early winter I’m sure the plummeting temperatures is a major influence on egg laying by the queen.

‡ National … Ha! Most are only national if you live within the M25. Anywhere else and you’re usually much better off accessing some data from closer to home. It’s worth noting that the sort of ‘amateur’ weather stations I discuss do vary in data quality. For example, they’re a bit dodgy recording temperatures in full sun (they tend to over-read). However, if you find a local one, check the temperature in comparison to a thermometer in your apiary, you’ll find it’s a useful way to monitor what might be happening in the hives.

§ I don’t routinely generate these graphs – I have a life (!) – but did specifically to illustrate this post. It’s sufficient to simply monitor the average temperature.

Colophon

Whether the weather be fine
Or whether the weather be not,
Whether the weather be cold
Or whether the weather be hot,
We’ll weather the weather
Whatever the weather,
Whether we like it or not.

Anonymous

 

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