Tag Archives: autumn

Use them or lose them

Colonies with queen problems at this time of the season are unlikely to get through the winter. It’s therefore better to identify these early enough to try and rescue the situation. Having completed my Varroa treatment I check colonies to determine whether they have a laying queen. If the colony is piling in the pollen, bulging with bees and has few, if any, drones I don’t even bother to open the box. In contrast, a colony with any of the following signs gets a more thorough check:

  • little or no pollen being taken in … remember this might be because there’s none available, another example of where comparisons between colonies are useful
  • slow to take the fondant down (or syrup, though I only now use fondant for autumn feeding), but not because the box is obviously already stuffed with stores
  • lots of drones (almost all of these should have been evicted by now), indicative of a drone laying queen
  • an obviously weak colony

With a perspex crownboard you can detect all of these without disturbing the bees or opening the box.

I checked the colonies in one of my apiaries as I’d noticed two that were causing some concern at the final OA vaporisation treatment. One had a good level of stores, but the colony was weak and there were no eggs, larvae or sealed brood. The clipped and marked queen – mated earlier this year – was still present but had clearly failed* and, this late in the season, there was no chance of the colony replacing her. The bees were otherwise fine, with no signs of disease, well tempered and were well worth saving.

Rescuing the situation

I disposed of the queen and united them over newspaper with a strong colony on a nearby hive stand. In a few days I’ll put a clearer board under the upper brood box, then rearrange the frames of stores to leave the remaining box packed. Any spare frames of stores – and there should be at least half a dozen – will be used to boost other colonies.

Uniting over newspaper ...

Uniting over newspaper …

Of course, I’m not really saving these bees at all. Instead I’m using their potential to strengthen another colony, so maximising the chances of getting the recipient colony through the winter. With no brood of any sort in the colony it’s likely the queen failed at least 3 weeks ago. This means that the bees present were unlikely to be ‘winter bees’ and would therefore be expected to perish over the next few weeks. However, in the meantime, they will help strengthen the recipient colony – enhancing it’s ability to raise new brood and increasing the pollen and nectar collected as the season winds down.

Nearly ready

Nearly ready

The second colony was weaker than I’d have liked, but – reassuringly – there were 2-3 frames of brood in all stages, together with an unmarked and unclipped queen. Since all the queens in the apiary were clipped and marked earlier in the season this was clearly a supercedure queen, raised in the last few weeks. The colony was beautifully calm so I gently closed them up. My bee house will be ready soon, so I’ll make sure this colony is one of the first to occupy it. The additional shelter should help them through the winter. With the new queen laying well and the weather set fair for the rest of this week, there’s a good opportunity for the colony to build up before they’re moved.

* Remember … some Varroa treatments can cause the queen to stop laying. For example, Apiguard is tolerated by some queens but not others who can stop laying for two or more weeks. The colony with the failed queen (above) had not been treated with Apiguard so I was pretty sure she was a dud.

Sublime sublimation

Sublimox vaporiser

Sublimox vaporiser …

Sublimation is the conversion of a substance in the solid phase into the gas phase without going via the intermediate liquid phase. With suitable heating oxalic acid (OA) powder can be converted into a vapour which, when spread through the hive, provides a quick and effective way to reduce the mite levels … hence it’s often referred to as oxalic acid vaporisation (or vaporization … if you search the web on this topic you’ll find at least four variant spellings). With too much heating OA decomposes to formic acid and carbon monoxide, so the temperature of the vaporiser is critical to generate the optimal cloud of OA vapour (or vapor!). I’ve been using a Sublimox vaporiser this season with good results and provide a description of the machine and its use here.

Vaporisation vs dribbling

Most beekeepers are familiar with midwinter treatment with 3.2% OA solution (in syrup), applied by ‘dribbling‘ 5ml per seam across the clustered colony. Under these conditions the colony needs to be broodless as a) it’s not effective against mites in capped cells and b) the OA dissolved in syrup is toxic to brood. It’s also reported that the ingested OA may be suppress subsequent brood rearing, at precisely the time the colony should be getting started for the upcoming season. Vaporisation or sublimation avoids this toxicity … the OA is introduced to the hive as a gas which permeates the entire colony, recrystallising as tiny crystals on all surfaces – bees, comb, internal walls etc. Studies of OA vaporisation has shown it is ~95% effective in reducing phoretic mite numbers. I recommend you read the extensive coverage by Randy Oliver @ Scientific Beekeeping who covers efficacy, mode of action and toxicity (though I’ll return to this last bit later).

Sublimox vaporiser

This is an active vaporiser which blows a jet of vaporised OA through a small (8mm) nozzle. The machine consists of a handle, a box of electrickery (which I’ve not opened) and a heating pan surrounded with a safety guard. The machine is rated at 230V AC and 300W so you need either a car battery and inverter or a suitable generator (which is what I use). The vaporiser is simplicity itself to use. One gram of OA powder is placed into a small plastic ‘cup’, the preheated vaporiser is inverted and the ‘cup’ engaged with the heating pan. The nozzle is pushed through a hole in the hive body and the vaporiser is inverted again (so it’s now the correct way up – see the top photo on this page). The OA drops into the heating cup, immediately vaporises and is blown through the nozzle into the hive. It takes 40-50 seconds to use all the OA, at which point you can move on to the next hive.

This video shows the effect of dropping a few millilitres of water into the heating pan … it’s almost exactly the same when using OA, but less likely to cover my camera with a fine dusting of OA crystals 😉

Preparing the hive

Entrance block

Entrance block …

To fill the hive with vaporised OA it’s important that as little as possible leaks out during the short period of treatment. I use a Correx Varroa tray underneath the open mesh floor. In addition, the kewl floors I use are easy to block using a simple L-shaped piece of softwood (I use these when transporting hives; when screwed onto the front of the floor there’s no danger of bees escaping). Part of the beauty of OA vaporisation is that the hive does not even need to be opened. I’ve drilled 9mm holes just above the open mesh floor level, through either the side or back of my floors. This is a better location to insert the nozzle of the Sublimox as there’s space under the frames to allow the gas to spread evenly and quickly throughout the hive. This is easier than the alternatives of using an eke with a suitable hole in it, or drilling through the side wall of the brood box (this is too close to the frames and you get poor spread of the gas – I’ve tried this on hives with a perspex crown board and it’s very obvious).

With a standard floor you could use a simple entrance block with a suitable hole in it. The nozzle gets hot … keep it away from poly hives or nucs! I treat my Everynuc poly nucs directly through the (cavernous) front entrance which I block using a thick piece of wood with a 9mm hole through the middle.

Preparing the beekeeper

OA vapour is pretty unpleasant and causes significant irritation to the eyes and lungs if exposed. Take care. You will need suitable eye protection and a mask of some sort. I use standard (and very inexpensive) safety goggles and a 3M dust/mist mask. You should also wear gloves when handling OA. It’s also wise to stand upwind of colonies being treated and to take care not to breath in any OA vapour that leaks out of gaps in the hive.

In use

I’ve treated four swarms this year using OA vaporisation. Three had very low mite levels, but the small churchyard swarm dropped several hundred mites in the 2-3 days following treatment. I don’t routinely count the mite drop on each day post treatment (I have a life) but have noticed it can increase over the first 2-3 days and then tails off over the following week or so. In large scale studies in Europe 95% efficacy was reported with mite drop continuing for up to a fortnight. There are a number of useful references on the Scientific Beekeeping site if you want to follow this up further.

I’ve also used OA vaporisation on almost all my colonies this autumn, instead of Apiguard treatment. If the colony has sealed brood the usual estimate is that at least 80% of the mites are occupying capped cells. These mites are unaffected by OA vaporisation (until they emerge) and it is therefore necessary to perform repeat treatments. Taking account of the life cycle of the mite and empirical measurements made by Hivemaker reported on the Beekeeping Forum, three treatments at five day intervals are required to have the maximum effect. Ideally this should be on a day or at a time when most of the colony is ‘at home’ … though the crystallised OA continues to be effective for several days after initial treatment. Fortunately, OA vaporisation has little or no effect on the queen, unlike many other mite treatments. The colony gets mildly agitated during treatment but calms down again within minutes and resumes foraging. In the colonies I’ve looked at after treatment there appears to be no gap in egg laying (I’ve also treated casts with virgin queens that have gone on to mate successfully). This is ideal for the autumn treatment when you want the colony to raise as many bees for overwintering as possible. In contrast, Apiguard regularly stops the queen from laying.

And finally …

There are other OA vaporisers made, and instructions on the web for a variety of DIY items – some looking more dangerous (to the operator, not the mite) than others. The majority of these are passive vaporisers, in which the OA is placed in a cool heating pan which is then placed on the floor of the colony and heated up. I’ve not used this type. They have the advantage of being less expensive and only require a 12V supply. However, they are slower to use as the pan takes longer to heat up and then needs to be cooled in a bucket of water between applications. They are also incompatible with the kewl floors I use and I presume – depending on how hot they get – with poly hives and nucs. I think the efficacy of the two types is supposed to be broadly similar.

I listened to Bob Smith talk at the MSWCC conference last week on shook swarms. I sat there thinking that a shook swarm followed shortly afterwards by a single shot of OA vapour would give a colony a really good opportunity to build up well, free of pathogens that have accumulated in the comb and free of the majority of phoretic mites and their viral payload.

Economics

The Sublimox vaporiser is not inexpensive. It costs about €380 from Icko Apiculture. This is a lot, but is about the same as three 3kg tubs of Apiguard (C. Wynn Jones list this at £87 a tub at the time of writing) which is enough to treat 90 colonies with two treatments per colony. In contrast, OA dihydrate powder in bulk (not from Thorne’s) is about £20 for 5kg … enough for 1250 colonies (assuming 4 treatments per colony – 3 doses in the autumn and one midwinter). For beekeeping associations, particularly those with large shared apiaries when treatments could and should – see a later post – be coordinated, it might be a very good investment.

 

MSWCC 2015

DWV symptoms

DWV symptoms

I spent last Friday and Saturday attending the Midland and South West Counties Convention at the Royal Agricultural University, Cirencester. It was a good venue for a meeting, complemented by an interesting and entertaining programme of talks. I presented our research on the influence of Varroa on the transmission of pathogenic strains of deformed wing virus, together with brief coverage of both high and low-tech solutions that might be useful in mitigating the detrimental impact of the mite on the virus population (and hence, the colony).

Queen rearing course

Queen rearing course

On the Saturday I donned my beekeepers hat (veil?) and discussed queenright queen rearing methods – a talk really aimed at encouraging beginners to ‘have a go’. I’m was aware there were people in the audience who earn their living from bees whereas I largely dabble at the weekends, and that they’ve probably forgotten more about queen rearing than I’m ever likely to learn. I’m always (silently) grateful they don’t ask tricky questions or interrupt with a “You don’t want to be doing that …” comment. I think only about 10% of beekeepers actively raise queens – by which I mean select suitable larvae and generate ‘spares’ for increase, sale or giving away. Without more learning how relatively easy it is to raise queen we cannot hope to be self-sufficient and will remain reliant on imported stocks, of largely unknown provenance (and with an unknown pathogen payload), particularly at the beginning and end of the season. There were excellent presentations on the analysis of pollen in forensic studies (Michael Keith-Lucas) and the use of the shook swarm (Bob Smith), together with a very interesting mead tasting event. I unfortunately missed the workshops and the Saturday afternoon presentations as I had to waste hours hanging around for three delayed trains to eventually get to Heathrow a few minutes after my flight back to Scotland departed 🙁

The MSWCC 2016 event will be running again next year (on the Gower) in mid-October hosted by Swansea and District BKA. The theme is “Meet the Natives” and – if this year is anything to go by – it promises to be a very worthwhile event.

I love the smell of propolis in the morning

[to paraphrase Lieutenant Colonel Bill Kilgore] … actually, I love the smell of propolis more or less anytime. During the quiet winter period the warm, spicy scent of propolis is a lovely reminder of hive inspections during warmer times. It’s one of the characateristic smells I associate with beekeeping, along with the lemony scent of the alarm pheremone – something best avoided – and the pretty rank smell of brood frames sterilised in the steam wax extractor (definitely best avoided).

Clearer boards

Clearer boards …

A couple of night ago I extracted the summer honey collected by the bees since moving to Scotland. There were only a small number of supers to extract; many of the colonies I brought North were nucs and have only recently moved up into full boxes, coupled with it being a rather poor summer. I’d added clearer boards under the supers the day before removing them then stacked the supers on top of my honey warming cabinet for a couple of days until I had time to do the extracting. By keeping the supers warm – the temperature in the headspace above the top super in the stack was only about 30ºC – the honey is much easier to extract than when cold and viscous.

The other effect of warming the supers is that the propolis softens and then sticks to just about everything it comes into contact with. The frames in these supers hadn’t been moved for 6-7 weeks and were heavily propilised to the runners and each other. Inevitably, prising the frames out and manhandling them in and out of the extractor meant my hands got covered with propolis. Like cooking with onions, the smell of propolis lingers well into the following day, irrespective of how well you wash your hands.

It’s been a rather poor second half of the season and many of the frames were uncapped. However, the honey – even when warmed – couldn’t be shaken out of the frames indicating that the water content was low enough to not ferment (and when measured it was almost all about 17%). The honey was sufficiently runny to filter through coarse and fine filters directly into 30 lb honey buckets for storage before jarring. This is the first honey produced by my bees in Fife and I’ll have to get some new labels designed that correctly lists its provenance.

Fondant block and Apiguard

Fondant block and Apiguard

Finally, before disappearing for a few days to  Andalusia I added a queen excluder and an empty super to every hive to accommodate a 12.5 kilo split block of bakers fondant. This is a really easy way to feed colonies up for the autumn. They take the fondant down more slowly than they would take thick (2:1 w/v) syrup which I think ensures that the queen has ample space to keep laying – these will be the important winter bees that get the colony through to the next season. It also doesn’t seem to encourage either robbing or wasps – perhaps because there’s nothing to spill. It’s also a whole lot easier to prepare … just slice a block in half with a breadknife. I simply add the fondant face down over the queen excluder, reduce the entrance if the colony isn’t at full strength, close them up and walk away*.


 

* I also added a tray of Apiguard to a couple of colonies as the first stage in autumn Varroa treatment. The majority of the colonies are going to receive vaporised oxalic acid but I wanted to do a side-by-side comparison of the effect on queen laying, so two colonies in one apiary received Apiguard.

Not beekeeping …

… pretty much describes my August. Having moved from the Midlands to Fife at the very end of July, with a new house and new job to sort out, I’ve had almost no spare time for my bees. Fortunately, August is usually a pretty quiet month. The swarming urge is more or less over and – with good weather – the colonies should be piling in the nectar. Unless you’re queen rearing – and I’m not – it’s a time to sit back and look forward to the fruits of their labours.

Tentsmuir fireweed

Tentsmuir fireweed

All the colonies I moved up in a van settled well in their new apiaries. The majority are in a temporary site while my beehouse (about which more in a later post) and main apiary are prepared. The remainder are in a friend’s garden, in a lovely sheltered South East facing spot. The fortnight after moving them the weather was very unsettled and there were reports on the SBAi forum about the risk of starvation. It’s been unseasonably wet throughout July (200% of the 30 year average rainfall) and there was nearly no nectar available. Large colonies were OK, surviving on their stores or even collecting a bit here and there. In contrast, nucs were very low on stores and dangerously close to starvation. I’ve noticed this type of threshold effect before, where only the larger colonies have sufficient foragers to exploit limited nectar sources. I know that others think that the colonies most at risk are those with a large proportion of open brood – whether nucs or full colonies. This might be the same thing, just described in a different way. These nucs were expanding fast and had quite a bit of open brood. I gave all of them a block or two of fondant, either dropped directly into the feeder of the Everynucs, or laid across the tops of the frames in Paynes poly nucs.

Within days the weather picked up, the colonies quickly used up their fondant and several of the larger nucs (the 8-framers in butchered Paynes poly nucs) all started running out of space. I moved these into full sized hives. At the same time the full colonies had started piling in the nectar so a few were given extra supers in the hope of getting a bit of honey late in the season.

Give them more supers ...

Give them more supers …

As soon as this period of settled weather looks like ending it’ll be time to start thinking about preparations for the winter. This means taking and extracting any honey, Varroa treatment and feeding up the colonies. I usually like to get my Varroa treatment completed early as Apiguard (which I routinely use) has a tendency to stop the queen from laying. On warm early autumn days the smell of thymol in Apiguard-treated hives can be overpowering. However, this year I’m going to use vaporised oxalic acid on the majority of colonies. I’ve used this a few times already this year – on colonies with undesirably high mite levels early in the season and on swarms – and think it’s very well tolerated by the colony, with no apparent interruption to egg laying by the queen. By treating three times at 5 day intervals – to account for the sealed brood in the colony – at the same time as I feed fondant I hope to let the queen lay well into the autumn, generating the all important winter bees that will get the colony through to the next season.

Note … this post has been sitting unfinished on my Mac for a week or more as I struggle with an endless pile of boxes to unpack. The weather looks to be gradually deteriorating and the supers will probably be taken off this weekend.