Autumn varroa treatment

Now that we have taken off this year's honey crop we can start thinking about the bees' health before they go to bed for the winter.

There are many pests and diseases that can afflict a bee colony but the one that requires the most careful management is the varroa mite. These are tiny mites less than a millimetre long that stick to and feed on the bees, and especially the larvae.

Varroa is endemic now in the UK so you cannot just hope your bees are not affected. There are a number of ways to reduce the number of varroa mites in the hive and this autumn we have chosen to treat the hives with Apivar which is a pesticide developed for this purpose.

Apivar treatment is dead easy. It comes impregnated into plastic strips which are simply hung between the brood frames using matchsticks.

We did a rough count of the number of mites in each hive before treatment. Hives 1, 2 and 4 had pretty low varroa, but hive 3 had high infestation so needed pretty urgent treatment.

After the Apivar being in for a week we did another varroa count (you count the number of mites that drop out of the hive onto a special board that is slid under the hive). Sure enough, hive 3 had dropped a massive number of mites - I lost count but it was 300-400 mites.

We'll be inspecting the bees less frequently from now on. Our main check will be to ensure that the colonies are big enough and have enough food to get them through the winter.

You can read more about varroa and how we managed it earlier in the year in this previous post:
http://cpbees.blogspot.com/2019/02/winter-varroa-treatment.html

Honey Extraction – in photos

We extracted 44 frames of honey, making over 150 jars. The profits from the sale will be going to Autistica.

 Five supers, containing 44 frames of honey.

Two full super frames. The white caps are wax, applied by the bees to seal the honey in.

Using an uncapping fork to remove the wax caps.

 

 Centrifuge extractor that can take 9 frames at a time.
 

Running honey out of the extractor through a double sieve. That is the only treatment the honey receives. Spun. Sieved. Jarred.

 Extracted honey in settling tank, plus two other buckets because we had so much.
 

Extracted super frame, called a “wet super”.

Queen Marking

When inspecting a hive it makes a huge difference to be able to quickly see the queen, so beekeepers generally paint a coloured dot on the back of the queen’s thorax. This is either a blob of paint or a coloured dot attached with glue.
We have new queens now that we have reared following splitting our hives at the end of April. We have now marked two of them.
The colour of the dot is used to show which year the queen was born.

• Years starting with 0 or 6 have a white dot.
• Years starting with 1 or 7 have a yellow dot.
• Years starting with 2 or 8 have a red dot (our two original queens, born last year, have red dots)
• And so on with green, followed by blue.

So our 2019 queens have been marked with a green dot.
Catching and marking a queen is tricky. She is delicate and the last thing you want to do is damage her. Fortunately our beekeeping mentor Mark was on hand to help.
There are various ways of catching your queen. Experienced beekeepers just pick her up and hold her by the legs. We used a “one handed queen catcher”, which is a plastic tube that is placed over the queen on the honeycomb. A slotted screen is then rolled across the tube entrance to catch her in it. A foam-coated plunger is then pushed up the tube, which allows you to secure her between the screen and the foam top of the plunger. Then she is held firmly and can be marked with a paint pen. The photos below hopefully make it a bit clearer!

New Queens

We’re pleased to report that we have new queens in the colonies we divided four weeks ago. These young queens will have been reared by the worker bees following being split away from the “mother” colony. The new queens will have emerged a week or two ago. In some colonies we have already found that the she is laying eggs so will have been out on her mating flight.

I caught a photo of one of our new queens, which is nice because it shows the new (as yet unmarked) queen, and also a worker and a drone.

You can see that the queen is longer and has bigger sections to her abdomen and no stripes.

The worker has a much shorter but striped abdomen.

The drone (male) on the other hand is all round much larger, wider and darker than the workers. And they have huge eyes that meet at the top of their head.

Honey

We’re very pleased to see that more nectar is coming into the hives and the bees are busy converting it to honey. We have some more “supers” (the smaller top boxes that hold honey) on order as the current ones are getting full already! Honey will be extracted in late
summer.

Hive splits

April is a busy time for honeybee colonies, and with the good weather we have had over the last couple of weeks, our hives have been expanding rapidly. We’re delighted with this, because the “supers” (the top boxes where the bees store honey) on both hives are now full of honey!














So rapid expansion is good news in a way for the beekeeper, but it is also a big concern. When a colony gets too full and runs out of space they will generally form a swarm, and half of the worker bees and the existing queen will leave the colony to set up home elsewhere. Beekeepers put a lot of effort into trying to avoid that happening, because it is rare that you can catch them and get them back. So you suddenly end up with a colony half the size.

One way to deal with potential swarming is to split the hives before they get chance to swarm. The queen and half of the workers are moved into a new hive (so they think they have swarmed), and the remaining bees are left behind in the original hive (as if the bees had already swarmed and left).

So with the guidance of our mentor Mark we split both our hives into two. But the orange hive was so close to swarming (literally a day or so) we were also able to set up two new “nucs” (nucleus colonies) in the small box.



During this work on Wednesday I caught the photo below, which I have annotated to show some of the interesting features of a hive.



Unsealed worker larvae. These are the baby bees before they pupate. Look for the white grubs, curled in the bottom of the cells. These are fed by the worker bees.

Sealed worker brood. Once the larvae are ready to pupate, the workers seal the cells with “biscuit” coloured wax caps. From these will emerge young adult work bees.

Sealed drone brood. Drones (male bees) are bigger. You can recognise sealed drone cells because they have a dome-shaped wax cap. So our colonies are rearing drones, which tells us they are preparing to swarm (drones are needed to mate with the new queens).

Queen cup. When a colony is preparing to swarm it will build a number of “queen cells”, one of which will produce the new queen to head the colony after the old queen has left with the swarm to set up camp elsewhere. The workers start by building a “queen cup”, into which the current queen lays an egg.

Sealed Queen Cell. Once there is an egg in the queen cup, the workers build it into a long cell that hangs down vertically (rather than being horizontal like all other cells). The presence of this cell in our orange hive was the red flag: once a queen cell is sealed the queen is encouraged to leave the hive with a swarm. So we caught it just in time.

Looking forward, we have a lot to keep an eye on over the next few months. We still need to inspect the old colonies to ensure they do not build up and try to swarm again. And we need to see that the new colonies get a new queen, and that she goes out and mates and starts laying eggs.

First inspection of 2019

It was a very nice day today and Ste and I did our first inspection of 2019.
We were very pleased to see that both colonies are doing well and have survived winter fine. They have lots of stored food and are bringing in lots of pollen at the moment. The queens were well in both colonies and have both started laying eggs so new young worker bees are now starting to emerge.
Here are a few photos.

Winter Varroa Treatment

The Varroa mite is a parasitic mite that feeds on honeybees and their
larvae. It rejoices in the latin name varroa destructor.
It first appeared in the UK in 1992, and has since spread across the
entire country and is found in every beehive. Despite its latin name, the
varroa mite does not immediately destroy a colony. To do so would
result in killing itself as well. Instead the mites reproduce gradually, build
their numbers over time. Beekeepers have learnt to monitor and manage
varroa mite numbers so they do not get too high.
Varroa mites prefer to feed on larvae when they are sealed in their
honeycomb cells developing into adult bees. This results in weak and
disabled bees emerging. These are unable to contribute to the work of
the colony and are instead a burden. If the number of varroa mites gets
too high the final result is colony collapse, where the healthy bees can
no longer sustain the colony.

Varroa mites on the back of a bee.

How do we monitor varroa mite numbers?

Modern beehives incorporate a tray at the bottom of the hive that allows a sheet of board to be inserted to catch anything that falls from within the hive. Much of what falls is pollen, but occasionally a varroa mite will fall too. The “varroa board” is generally left under the hive for a week and then removed and the number of varroa mites counted. The number of mites on the board can be used to extrapolate the varroa population in the hive.
Varroa mites are tiny (less than 1mm across), but they have a distinctive shape and shine to their outer shell. With practice they can be counted fairly easily. This is my daughter counting mites from our bees.

How do we reduce the number of varroa mites?

It is not possible to eliminate varroa mites all together. But there are a number of techniques that can be used to reduce their numbers. Once the numbers are reduced to tens rather than thousands in the hive it takes some months for their numbers to increase again.
Mite numbers can be reduced by using various pesticides that have been developed specially for beekeeping. In addition, there are non-chemical techniques that can help to reduce mite numbers, such as having an open mesh floor rather than a solid floor to the hive. Most beekeepers use a mixture of these techniques to keep the mite numbers as low as practical.
One very effective pesticide treatment is oxalic acid, which is mixed with sugar syrup and applied directly to the bees. This is best done when there is no brood – that is, no larvae sealed in honeycomb cells. This tends to happen in winter when the bees are dormant. With all the mites out of honeycomb cells they are much more vulnerable to the effect of the pesticide.
So in mid January we applied oxalic acid treatment to our bees. It’s a quick job: once the chemical is mixed with the sugar syrup it simply needs to be gently squirted over the bees in the hive. Because it is cold outside the hive should not be open for long. We made sure the hives were only open for a couple of minutes. As you can see from the photos, we still got covered in sleepy bees!

A week after the treatment we checked the varroa boards again. If you look closely at the photo below you can see hundreds of mites have died and dropped out of the hive. Result.