miticide Archives - The Apiarist

The poor cryptic crossword clue in the title of course refers to an eke.

In beEKEeping, an eke is a wooden frame, the same dimensions as the hive, used to provide temporary additional volume to the hive.

They are useful and versatile pieces of equipment.

Etymology

The word eke can be traced back to Middle English (eke or eake) when it meant “an addition” and was derived from the the Old English (ēaca) and the Old Norse (auki) words of the same meaning.

In Old English it usually referred to a reinforcement of troops, but in 1549 it was first used ¹ to indicate an addition to the tag end of a bell-rope.

And then, a mere 308 years later it was used to describe a cylinder on which a beehive was placed to increase its capacity.

Swarm in a skep …

‘Cylinder’ of course, because in 1857 most beehives were probably still straw skeps ². A more extensive definition from the same period was a small addition to the bottom of a beehive, often just a few strands of straw, on which the hive was temporarily raised.

Most of us don’t use skeps any longer (other than for swarm collection) but we do use ekes.

Don’t buy it, build it

For some time I’ve reckoned that the appropriately-named dummy board represent the single item with the largest profit margin for manufacturers of beekeeping equipment.

I’m wrong. It’s the humble and unassuming, but oh so useful, eke.

At its most simple, an eke is a made of four bits of wood, screwed, nailed or glued together at the corners, square ³ and true. It doesn’t need to be made out of the best quality cedar.

In fact, it doesn’t need to be made of cedar at all. Any readily-available softwood with a couple of coats of wood-preservative slapped on top will be just fine.

Look back at the definition of an eke. Now, as in 1857, it was meant as a temporary addition to the hive. Cuprinol is just fine, best western cedar is overkill.

A cute rabbit, not rabbet, from http://www.bbbvet.org.uk

No … rabbet. R a b b E t.

I shall leave the precise design and details of building an eke as ‘an exercise for the reader’. You can achieve ‘square and true’ by using a simple square of plywood as a template. I’d suggest gluing and screwing the corners using a simple rabbet joint. Paint the entire thing with a couple of coats of bee-friendly wood preservative and you’ll have saved at least £20 on the prices some of the commercial suppliers charge.

Dimensions

Length and width are the same as the hive, depth is the important one.

You can make an eke any depth you want. You can usually buy them in only two depths.

Shallow (~20mm) – to provide just enough space over the brood frames when applying Apiguard treatment in the autumn. I can’t think of alternative uses that need an eke this shallow.
Deep (~90mm) – to convert a regular brood box for use with 14 x 12 frames ⁴.

Rabbit, er, rabbet joint …

All my ekes are made from 20 x 44mm (thickness x depth ⁵) softwood. This just happened to be the wood I could easily get when I first started building them, but has turned out to be a very useful depth overall.

Build more than one. Unless you only have one hive. In which case buy another hive and then build another eke. I’ve got about two-thirds the number of ekes as I have hives and I regularly run out.

Feeding and treating

Use your wellie …

The most frequent use for an eke is to provide space above the frames and below the crownboard, for example when feeding a colony fondant or applying Apiguard. It takes just seconds to lift the roof and crownboard, position the eke, add the fondant or tray of Apiguard and cover the hive again. In the days when I used to use Apiguard I’d often add the fondant at the same time ⁶. What could be simpler?

With care (or a lot of flattening the block by standing on it repeatedly) it’s possible to easily squeeze 6-8kg of fondant into the void provided by a 43mm eke. Since I usually feed a full 12.5kg block of fondant in one go – sliced in half and opened up like a book – I simply pop an eke under an inverted insulated crownboard to provide the ‘headroom’ needed.

Vaporising with an eke …

Whilst we’re on the subject of applying miticides … I also use ekes when administering vaporised oxalic acid-containing treatments to colonies in polystyrene hives. The nozzle of my Sublimox vaporiser gets hot enough to melt polystyrene. Rather than messing around trying to aim the billowing cloud of vapour through the entrance it’s much easier simply adding a wooden eke to the top of the brood box and pushing the nozzle through a 7mm hole in one side. The vapour easily permeates to every corner of the hive ⁷.

Travelling

Travel screens are used in place of crownboards and roofs when colonies are being moved any distance. They are usually framed wire mesh of some sort. They are important as they stop colonies overheating during the stress of transporting them. You can also easily spray water onto the colony to help cool it if needed.

They are yet another thing that spends 98% of the time stacked up in a corner with all the other oddities of beekeeping – clearer boards, Miller feeders, weirdo split boards and custom-made shims for uniting mismatched hives.

Travel screen mesh and eke …

I don’t bother with travel screens, but instead use robust ‘glassfibre’ insect mesh held securely in place with – you’ve guessed it – an eke. I just lay the mesh over the open colony, add the eke and then strap everything thing up tight. This works a treat. The eke ensures that the mesh is held securely around the edges.

Abelo hives in transit …

Insulation and crownboards

I’m a firm believer in providing a block insulation over the crownboard, ideally all season, but certainly through the winter. I’ve built a number of reversible, insulated perspex crownboards … but I didn’t build enough

I’ve also bought, inherited or otherwise acquired several standard framed plywood or perspex crownboards. Using a 44mm deep eke and a suitably sized block of 50mm thick expanded foam you can easily cobble together a perfectly function insulated crownboard.

Another use for an eke …

And the rest …

There are all sorts of additional uses for ekes … stacking supers on, providing space under brood frames with protruding queen cells (for example, when moving a frame from one colony to another ⁸, doubled up to provide depth for 14 x 12 frames etc.

It’s worth keeping a couple of ekes stacked up with spare supers and broods in the apiary. They’re more useful than you’d think a simple square frame of wood should be.

Winter colony with eke, fondant and insulation …

There goes a few pence …

My recent comments on the cost of Api-Bioxal prompted me to look in a little more detail at the cost of miticides routinely available to beekeepers. The figures quoted below are the best prices listed by one of three leading beekeeping suppliers in the UK (E.M. Thorne, Maisemore’s and C. Wynne Jones – there are lots of other suppliers, but I’ve used these three and been satisfied with their service). I made the following assumptions: the beekeeper is purchasing sufficient to treat three single-brooded full colonies for three years (i.e. something with a reasonable shelf-life) with as little left over as possible. Costs per colony treatment were calculated for 9 colonies (3 x 3 years) only … any ‘spare’ can therefore be considered as free. This means that for Apiguard, available in packs of ten trays (5 colony treatments) or a 3kg tub (30 colonies), the cost is calculated per colony from two packs of 10 trays as a full course of treatment for one colony requires two trays. Obviously, buying in bulk – for example through a co-operative purchasing scheme in your beekeeping association – should reduce these costs significantly. No postage costs were included.

Apiguard – two boxes of 10 trays (C. Wynne Jones) = £41 = £4.55/colony

Apistan – two packs of 10 strips (C. Wynne Jones) = £41 = £4.55/colony

MAQS – one 10 dose tub (all suppliers) = £57.60 = £6.40/colony

Api-Bioxal – one 35g sachet (C. Wynne Jones) = £8.20 = £0.91/colony

Oxalic acid (OA) crystals – one 300g tub (Maisemore’s) = £4.32 = £0.48/colony

Note that this simplistic comparison hides a number details.

These various treatments should be broadly similar in their efficacy (see below) in reducing the mite population, but must be used according to the manufacturers instructions for maximum efficiency. Under optimal conditions all quote at least 90% reduction in mite levels. However, Apistan (and Bayvarol, not listed) is pyrethroid-based and resistant mite populations are very widespread. In the presence of totally or partially resistant mites, Apistan will be of little or no benefit. Interestingly, Apistan resistance (which, like resistance to pyrethroids in other species, is due to a single amino acid substitution, so readily selected) appears to be detrimental to the mite in the absence of selection. This means that it may be possible to use Apistan effectively every 3-5 years as part of an integrated pest management as long as other beekeepers in the area follow the same regime. During the years Apistan is not used the pyrethroid-resistant mites should reduce in number, so restoring the efficacy of the treatment. I’m not aware that this idea has been properly tested, but it might be worth investigating.
Only the first four treatments are approved for use in the UK by the VMD.
Both the oxalic acid-containing treatments – Api-Bioxal and OA crystals – require preparation before use, or specialised equipment for delivery. OA vaporisation (sublimation) also necessitates both care and personal protection equipment to prevent exposure to the chemical which is a lung irritant. The costs indicated do not include these additional requirements.
The treatments are not equivalent or necessarily interchangeable. For example, a) only MAQS should be used when honey supers are present, b) Apiguard is moved around the hive by active bees, so treatment is recommended when average daytime temperatures are above 15ºC , and c) there are reports on discussion forums of repeated OA vaporisation treatment – 3 at 5 day intervals – for colonies with brood present. The costs indicated above assume a single treatment (in midwinter or of a swarm/shook swarm in the case of OA) with any of the listed compounds.
Finally, the ‘excess’ amount spare after treating the colonies over three years differs significantly. The first four have sufficient left over for one further treatment. The OA crystals will have enough left over for a further 190 colonies … and buying a 300g tub is probably about the most expensive way to purchase OA per gram 🙂

Bang for your buck

As indicated above, all of the Varroa treatments listed should give 90+% knockdown in mite numbers if used properly. This means following the manufacturers’ instructions – in terms of dose, time and duration of application. A key point to remember is that the mite is only susceptible when outside the capped cell and that 80% or more of the Varroa in a colony at any one time will be inside capped cells if there is brood present. For this reason, it is preferable to treat during natural (or induced e.g. a shook swarm) broodless periods. It has even been suggested that the midwinter OA treatment should be preceded by destruction of any brood present. Although this makes sense, I can understand why some beekeepers might be reluctant to open a colony to destroy brood in the middle of winter. There have been numerous reviews of individual and comparative efficacy of the various Varroa treatments – for example this well-referenced article on mite treatment in New Zealand from 2008. If used properly there’s little to choose between them in terms of efficacy, so the choice should be made on the grounds of suitability, convenience and cost.

‘Suitability’ is a bit of a catch-all, but requires you broadly understand how and when the treatment works – for example, Apistan is a pyrethroid so works well against sensitive mites, but is pretty-much useless against resistant populations, and resistance is widespread in the UK. ‘Convenience’ is generally high in the ready-prepared commercial treatments – it takes seconds to insert a tray of Apiguard – and much lower if the compound has to be prepared or you have to get dolled up in protective gear. In this regard, the absence of a pre-mixed liquid version of Api-Bioxal is a disappointment. Thorne’s still supply (at the time of writing) Trickle 2, a very convenient pre-mixed 3.2% w/v OA treatment for mid-winter trickling, but for how much longer? Similarly, the gloves, mask, goggles and power needed to treat a colony by OA sublimation makes it far from convenient for a single treatment.

Closing thought …

1 lb jar of honey …

Despite the great differences between the cost/treatment/colony it’s worth noting that even the most expensive is not a lot more than the price of a 1 lb jar of top quality local honey … just like the stuff your bees produce 😉 So, in the overall scheme of things, Varroa treatment is relatively inexpensive and very important to maintain colony health and to reduce overwintering colony losses.

See also Managing Varroa (PDF) published by the Animal and Plant Health Agency

The Apiarist

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