Category Archives: Wax moth

Autumn cleaning

Over the last fortnight, despite some occasional warm and sunny days, the autumn has made its presence known. 

Flaming autumn aspen

The aspen down the road are a stunning colour at this time of the year. Although I’ve planted a couple of dozen, they’re still not more than thigh-high and it will be quite a few years until they can match the display shown above.

Almost overnight hundreds of redwing have arrived from Scandinavia and many of the rowan have already been stripped bare 1.

In Fife, the leaden skies are filled with skeins of geese forming raggedy V’s as they fly in from the North Sea. It’s an evocative sight … it reminds me of my first weeks as an undergraduate student at Dundee University half a lifetime ago

And it also emphasises that the beekeeping season is over.

Of course, there will be jobs to do in the winter, but the bees are pretty much on their own for at least the next five months.

Apivar

The final essential task of the season for me is to remove the Apivar strips that went into the hives in August. Initially the strips were placed on either side of the – still large – brood nest. A few weeks ago I removed the strips, scraped them free of propolis and wax and re-inserted them around the, now shrunken, brood nest.

Mid-autumn and time for the Apivar strips to be removed

You can just about see them in the photo above, flanking the four central frames.

It is important to remove the strips. Although Apivar has a relatively short half-life, some residual activity will remain. If you leave them in the hive any surviving Varroa – and there will be survivors 2 – will continue to reproduce in the presence of trace levels of amitraz, the active ingredient in Apivar. 

With reduced – and possibly borderline for killing – levels of amitraz present, these are ideal conditions in which resistance may develop. Although this has been reported it does not appear to be widespread. 

Therefore, to ensure that Apivar remains an effective miticide it is important to remove any remaining strips before the winter.

Your next adventure in Glenrothes awaits!

Tragic isn’t it?

That’s the subject line on the emails I receive from Travelodge where I stay when I’m doing my beekeeping in Fife. 

Have you ever been to Glenrothes?

‘Adventure’ isn’t the word most people associate with Glenrothes. 

Good morning Glenrothes

GetMeOuttaHere is. 

This is a town where every third car being driven late at night has a raucous exhaust, lowered shocks, tinted windows and a spoiler. The drive-in queue for McDonald’s sounds like the pit lane at the Indianapolis 500 and there are more donuts in the car park than in the fast food outlets 3.

But none of that usually bothers me as, by the time I get to the hotel, I’ll have been driving for 5 hours and will have spent about the same amount of time inspecting colonies or lifting cleared supers. I may also have squeezed in a couple of hours of meetings at work.

The environment might be noisy, but the beds are comfortable. 

But visits in late autumn are a bit different.

No colonies to inspect, no grafting to do, no nucs to check for mated queens and no supers to remove.

All I need to do is gently lift a few crownboards and pull out the Apivar strips now that treatment is complete.

So, what do I do for the rest of the day?

Long range weather forecasting

Is that an oxymoron?

I book my trips to Fife to fit in with what the bees need. To make the hotel affordable I book many weeks in advance.

I therefore put up with whatever the weather throws at me. Usually it works out OK.

Furthermore, as regular reader know, several hives are in a bee shed, so the weather is largely irrelevant.

But ~60% of them are outside.

And Monday was really wet. 

Having driven for four hours through increasingly heavy rain – stopping en route to make a honey delivery – I fortified myself with a cappuccino and excellent almond croissant from Taste, the best independent coffee shop in St Andrews 4.

Essential fortifications

I then sat in the shed enjoying my late breakfast listening to the rain hammering on the roof.

I needed something to occupy me until either:

  • the rain stopped
  • it got so late in the day that I’d just have to open the hives and remove the strips anyway

And the obvious thing to do was a bit of spring autumn cleaning. 

During the season the bee shed is used on a daily or weekly basis depending upon the experiments underway. In addition, we have a storage shed on the same site and a number of additional hives in the same apiary. I also do most of my queen rearing in this apiary (the bee shed provides a near-perfect environment for grafting), distributing the nucs to other apiaries for mating.

And all that beekeeping tends to leave a bit of a mess. At least, it does where I’m involved.

Super job

For the last couple of years I’ve not bothered returning the extracted supers to the hives for the bees to recover the last of the honey.

Instead I’ve just stacked them ‘wet’ in the shed, protected from wasps, mice and robbing bees, by covering the top of the stack with a well-fitting roof.

Or a snug-fitting crownboard and a badly fitting roof.

Stacked ‘wet’ supers

Experience has taught me that the floor of the shed isn’t level and/or has gaps between the planking. Rather than seal all these gaps I simply stand the stack of boxes on the sort of closed cell foam sheeting used for packing furniture, or – when I run out – on double thicknesses of cardboard 5. This stops the wasps, ants and bees from getting access. 

So I started by tidying the stacks of supers. Inevitably this necessitated moving them first, sweeping the floor clean, laying out the foam/cardboard and then restacking them. There’s not enough space in the shed to move ~60 supers so they went out in the rain.

So I got wet 🙁

Floors, roofs, boards, unidentifiable objects and wax moth

Once they were back I could turn my attention to the other side of the storage shed which houses spare roofs, nuc feeders, floors, boards (split, crown, surf, Morris, Snelgrove etc. 6 ), a breeding colony of queen excluders 7 and a motley collection of other items that:

  • might come in useful
  • don’t logically belong anywhere else
  • appear valuable and/or difficult to make … but I don’t know what they are
  • are essential and were needed several times in the season … but I’d lost them 🙁

Sorting this lot out took another hour or two, and involved a further soaking as I needed to clear the space before I could refill the space.

Early on in the process … 

Is beekeeping the largest volume hobby?

… and when at least partial order had been restored …

Floors from Abelo, Pete Little and some homemade abominations

I also found several brood boxes full of drawn comb or sealed stores.

Excellent 🙂

And I found a nuc box lurking in the far corner containing comb riddled with wax moth 🙁

Wax moth larvae and damage

Aargh!

DiPel DF

Wax moth are something I’ve largely avoided or ignored for most of the last decade. The cold winters in Scotland seem to keep their numbers down.

Not this time … 

All of the infested frames were bagged up for burning at the earliest opportunity. The remaining brood frames were treated with DiPel DF, a suspension of Bacillus thuringiensis kustaki spores and toxins. If ingested by the larvae of wax moths, the δ-endotoxin component dissolves in the alkaline environment of the gut, is activated following cleavage by gut proteases and then ‘punches’ a hole through the gut wall.

Ouch.

And the spores germinate, allowing the bacteria to grow inside the larva.

As I wrote in a post several years ago about this treatment:

This isn’t good for the moth larva. Not good at all. Actually, it’s probably a rather grisly end for the moth but, having seen the damage they can do to stored comb, my sympathy is rather limited.

DiPel DF is non-toxic for bees.

DiPel DF

I’ve not had problems with wax moth infesting supers stored ‘wet’ … they’re after the old cocoons and other rubbish that accumulates in brood frames.

Vita used to sell a product called B401 – also a suspension of Bacillus thuringiensis spores and proteins – which was withdrawn from sale in 2019. Despite assurances that a replacement – imaginatively labelled B402 – would be available ‘soon’ it appears to only currently be sold in the US.

Out with the old … and the not fit for purpose

I was on a roll … 

All this organisation meant I discovered things that I’d lost … like a small stack of contact feeders hiding in the corner that had not been used this season as I hadn’t done any shook swarms.

There they are! Contact feeders lurking shyly in the furthest corner (unlike those brazen frame feeders at the front)

I also found some mini-nucs I’d built for queen mating almost 10 years ago. They were made of ply and housed a tri-fold full-size brood frame (you can now buy these, but couldn’t when I built them). 

Tri-fold brood frame

However, the ply was starting to delaminate and it was pretty clear that they wouldn’t survive a Scottish summer season so they were unceremoniously binned.

And I finally bit the bullet and got rid of all my XP Plus queen excluders. These were bought from Thorne’s a few years ago and had been used only when I ran out of everything else.

In principle they are a good idea. A white plastic queen excluder with bee space on the underside provided by a raised rim and a series of small X-shaped spacers that stand on the top bars.

XP Plus queen excluder (the plus must mean ‘plus warp’)

However, in practice, they’re rubbish. They were the ‘ugly’ in my 2017 description of queen excluders that included the phrase ‘the good, the bad and the ugly’.  

They warp really badly. The photo above – if anything – obscures the warp because the QE is not being held flat. When you place them under a super the centre bows up and contacts the underside of the super frames.

Rubbish. 

Out they went.

The little things

There’s something rather poignant about the death throes of the beekeeping season. It can end with a bang as autumn storms roll in, or it can end in a protracted stutter as intermittent good days allow the bees to forage late into October. 

Of course, it’s au revoir 8 and not a final goodbye

It forms such a large part of my life for six months of the year that little things found during the clear-out bring back a flood of memories …

Nicot cup and (partly squidged) queen cell amongst the debris on the shed floor

A Nicot cup and vacated queen cell reminded me what a good queen rearing season we’d had on the east coast. Although the first round of grafting was a near-total failure, successive rounds were excellent, and queen mating was very successful. One of the best seasons in memory 9.

Coffee stirrer … or AFB test kit

Not all the memories were good ones though. I received one of the dreaded ‘AFB alert’ warnings for the apiary and spent a very long couple of days checking every cell on every brood frame in every colony, and testing any that looked suspicious.

I don’t take sugar, and the coffee stirrer shown above is provided in the AFB LFD kit to lift the dodgy-looking larva into a tube for analysis. Everything looked clear, but it gave me a few very stressful days.

And … after all that tidying, and repeated trips to the industrial-scale bins, it finally stopped raining.

Finally … some practical beekeeping

I fired up the smoker and quickly, but gently, removed all the Apivar strips. The crownboards on all the hives were very firmly stuck down with propolis and the bees, although calm, weren’t exactly overjoyed to see me.

Autumn still life – smoker, hive tool, Varroa trays and Apivar strips

I still had another apiary to visit. With rain threatening there wasn’t time to monitor the level of brood present so I slipped cleaned Varroa trays under the hives. This will allow me to inspect both residual mite drop and look for the presence of the characteristic biscuit-coloured cappings when brood is uncapped.

And then, after about half an hour of practical beekeeping, I set off back to the west coast as the rain started again.

The Moidart hills – An Stac, Rois-Bheinn and Sgùrr na Ba Glaise

Two days later the Moidart hills had their first dusting of snow.

It’s official, autumn is here and the beekeeping season is over.


 

Being Certan

It’s November and the end of the ‘bee season’ is well and truly here. Inspections finished some time ago (or should have) and the winter Varroa treatments are completed (or should be).

My precious …

Preparation for the coming season should now be the priority. One of the first things that needs to be done is protecting any valuable drawn comb not covered with bees.

Drawn comb is a really precious resource and is well worth looking after carefully. All beekeepers are likely to have super frames of drawn comb after honey extraction. Some will additionally have drawn brood frames. Finally, beekeepers who do a lot of queen rearing may have drawn frames of drone comb. All can be re-used, in the case of super frames many, many times, so saving the bees the effort (and the nectar used) to draw fresh comb.

Super frames

I allow the bees to clean out super frames from which the honey has been extracted. I place them back on the hive in the evening and the bees clean out the traces of honey. After clearing them again I stack them outdoors carefully on a plastic or Correx ‘floor’ and a wasp-proof roof. Sometimes – though not every year due to forgetfulness – I treat them with acetic acid to kill Nosema spores. I’ll discuss this in a future post as I’ll be doing it this season. If I remember.

I’ve got super frames dating back to my first year of beekeeping that are still perfectly usable. Any with odd-shaped comb just get sliced back square to the sidebars with a breadknife.

Any which has had brood reared in it (for example, when the queen sneaks above the excluder, or I’ve run a colony as ‘brood and half’, both increasingly rare events) goes into the steam wax extractor.

Brood frames

Spare brood frames are a great thing to have at hand when making up nucleus colonies, during queen rearing or at a variety of other times. They deserve to be protected and stored properly.

Unless, of course, they’ve had more than about three years of use, in which case they are also usually rendered down in the steam wax extractor. Even these old ones sometimes get a reprieve. I give them one more season as the single frame of old brood comb in my bait hives. These manky old frames should also be treated with acetic acid to kill Nosema spores and protected and stored carefully.

Galleria mellonella and Achroia grisella

Lesser wax moth (12mm)

Lesser wax moth (12mm)

These are respectively the greater and lesser wax moth. They infest stored comb and favour brood comb with old cocoons, traces of pollen and larval faeces. If unchecked they can destroy your valuable comb, converting the lovely wax to a mass of silk-lined tunnels and dust. They much prefer brood comb to super comb and seem to avoid supers stored ‘wet’ i.e. extracted but not subsequently cleaned by the bees.

It’s difficult, but not impossible, to provide moth-proof storage for your comb. They can sneak through a surprisingly narrow gap in the joint of a brood box.

In early copies of Hooper’s Guide to Bees and Honey it was recommended to use paradichloro-benzene (or, more correctly, 1,4-dichlorobenzene) to protect your brood frames from the ravages of wax moths. This is the stuff that makes moth balls stink. It’s pretty unpleasant, potentially neurotoxic (for humans) and not something I want anywhere near my ‘honey for human consumption’ bees.

I’ve not got a current copy of Hooper, so don’t know what is recommended now, but there are much better alternatives.

Biological control

Wax moths lay their eggs in stored frames, the eggs hatch and the larvae (caterpillars) burrow through the wax, eating their way through the old cocoons and other rubbish, creating a huge network of silken tunnels which eventually trash the comb. They then pupate and subsequently emerge as moths to fly off and decimate more stored comb. Little blighters!

It’s the ‘eating’ in the paragraph above that makes them susceptible to biological control with Bacillus thuringiensis.

Bacillus what?

B401 Certan

B401 Certan

Bacillus thuringiensis is a bacterium. During its replication it generates spores and a so-called crystal protein that is lethal to the moth larvae in which it is replicating. I’ll return to the spores later … these are a thermally and environmentally stable form of the bacterium, protected by a thick cell wall. 

The crystal protein (or, more correctly, δ-endotoxin) dissolves in the alkaline environment of the insect gut, thereby making it susceptible to digestion by proteases present in the gut. This protease cleavage releases the active form of the toxin which inserts into the cells of the gut, paralysing the cells and finally resulting in the formation of a pore.

This isn’t good for the moth larva. Not good at all. Actually, it’s probably a rather grisly end for the moth but, having seen the damage they can do to stored comb, my sympathy is rather limited.

However, it’s very good news for the beekeeper. It’s particularly good because of the specificity of the toxin (which is often referred to as Bt-toxin). The vast majority of Bt-toxins used for biological control are specific for the larvae of the lepidoptera – the butterflies and moths. These have no activity against bees or other pollinators.

Since the only moth or butterfly larvae that occur in hives, or on stored comb, are the unwanted wax moths, this is an effective and safe way of preventing infestations.

Preventing, not curing. Once infestation is present the damage is largely done.

Biological control is compatible with organic farming methods, if that’s what floats your boat.

Certan

B401 Certan is the most commonly available and regularly used Bt-toxin for beekeepers. You can buy Certan from the majority of beekeeping suppliers. Certan is supplied in bottles containing the spores or protein toxin of Bacillus thuringiensis subspecies aizawai. You make it up in water and spray it onto both faces of the drawn comb you want to protect from wax moths.

Certan costs about £16 a bottle which is sufficient to treat 120 brood frames (~13p/frame). Certan is used at a 1:20 dilution in water i.e. a 5% solution. Full details are available from Vita Bee Health who are distributors for Certan. There’s a nice video on the Vita site which shows how easy it is to administer.

DiPel DF

DiPel DF

DiPel DF

As an alternative to Certan, some beekeepers use DiPel DF. This contains the kurstaki subspecies of Bacillus thuringiensis. Although a different subspecies, the toxin is equally effective and equally specific. DiPel DF is widely available from agricultural suppliers and costs about £55 for 500g. DiPel DF sourced from Italy is routinely listed on eBay at a much lower price.

Because DiPel DF isn’t specifically sold for beekeepers the recommended dilution to be used isn’t published. However, if you grow tomatoes under cover the recommended dose is 100g per 100 litres of water i.e. a 0.1% solution.

I’ve used DiPel DF at a 1% concentration. I mixed the powder thoroughly 1 part in 20 and then used this stock solution 1:5 to make the working-strength solution to be sprayed onto the frames. About 10 ml per side per frame is used, sprayed with a fine nozzle. At this dilution, DiPel DF costs about 2p per frame … a very considerable saving. It may be equally effective at 0.1% – I’ve not tried – in which case it would obviously be even more economical.

DiPel is listed as non-toxic for bees and it’s certainly effective against wax moth.

A pressurised hand sprayer works well to administer DiPel or Certan. You can usually get these sprayers from big supermarkets for a couple of pounds.

Spores store

The beauty of spores is that they’re very stable. This means you can store them for long periods without them ‘going off’. Neither Certan or DiPel DF make absolutely clear what the bottle contains – sometimes they refer to ‘active protein’, sometimes to ‘toxin’ and sometimes to Bacillus thuringiensis. Some even suggest a mix … Valent BioSciences, the manufacturer of DiPel DF claim that it contains an optimized blend of four potent Bt protein toxins and a spore. They should know. The DF suffix means ‘dry flowable’ by the way.

Whatever is actually in the bottle, it’s pretty stable. If you store the powder in a cool, dry, frost-free location it should be OK for several years. The safety data sheet for Certan states that it remains active for at least 5 years if stored unopened at 5°C or less.

Store frames

The Certan or DiPel-treated frames should be stored, dry, in empty brood or nucleus boxes. These are best stacked outside, protected from rain or being blown over, until they’re needed next season.

Which is a long way off, but slowly getting closer …


Hic!

Hic!

† Certan is also a well known and respected Bordeaux wine from the appellation Pomerol. The full name is Château Certan de May de Certan, which is both a bit of a mouthful and internally redundant. The middle ‘de May’ part of the name is derived from the Demay family, the original owners, who were of Scottish origin and lived in France from the Middle Ages.

Make sure you buy the right Certan … whilst the stuff from Thorne’s is not inexpensive, a 2005 Vieux Château Certan will cost about £360  🙁  However, this is a bargain when compared with a similar aged Petrus (which shares the same clay soil on the right bank of the Gironde) at ten times the price.

Oh yes … these prices are per bottle  😯