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Beekeeping methods Landrace The Driest The Wageningse Eng Varroa mite

The year 2023

Sun and frost on The Driest.

The year 2023 has been a good year for bees and beekeeper alike. All 11 hibernated colonies have survived, but one had been seriously weakened by chalkbrood. Therefore, I had to eliminate this colony.

There was a lot of rain this year. This was not only beneficial for nature, but also for the main honey flows in spring and summer and on the heather. Only a dry period from mid-May to the end of June caused a break in the development of the vegetation.

Due to the warm autumn, the colonies continued to breed for a long time, which resulted in high Varroa pressure, which had to be reduced by using oxalic acid in almost all colonies in December, during one of the rare cold mornings. This year I did not perform three-day mite counts on the Varroa board in autumn, but only monthly counts. This is certainly less accurate and does not allow for the construction of mite drop curves, but it is considerably less work…

All young queens on The Driest are locally mated. I didn’t bring any virgin black queens to the Neeltje Jans mating station this year. This had to do with the fact that I had created a lot of brood splits to relax the production colonies and thus suppress the swarming mood. As a result I had obtained many small splits. What also plays a role is that I have some doubts about the quality of the breeding material from Texel: the colonies are selected exclusively based on morphological characteristics but not on behavioral characteristics. The result of the local mating was very good: only 1 of the 14 young queens was not fertilised.

I have not made any temporary splits: all young colonies have been made by tapping bees and brood. This resulted in many small splits, but these can easily be united in autumn into colonies that are strong enough to hibernate.

This year we grew summer barley on our plot. The drought in May-June resulted in the crop remaining very low. When it started raining again in July, the weeds quickly started overgrowing the barley. This made it a bit of a challenge whether the quality of the grain would be sufficient, as the barley barely became dry enough. In the end we harvested a mediocre, but qualitatively acceptable harvest.

We sowed winter rye in October. Let’s hope that the heavy rain of winter 2023-24 will not throw a spanner in the works…

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The Driest Varroa mite

Varroa on The Driest winter 2022-23

The Varroa load was high this year, because autumn stayed warm for a long time. As a result, the colonies continued to breed for a long time, which played into the hands of the Varroa population. The consequences of this will become apparent in the spring of 2023.

I determine the Varroa pressure solely by counting mites on the bottom board. Hence, the natural mite drop, determined over a long period, from the beginning of autumn to deep winter, and also from the beginning of the year to late spring. I convert the counting results into the average mite fall per day. There appear to be large fluctuations, resulting in an erratic curve. That is why I also calculate the 12-day moving average and the cumulative mite fall over the entire counting period. These values give a much more reliable picture of the dynamics of the mite population. This makes differences between colonies more clearly visible.

The cumulative mite drop generally shows an S-shape, as we often see in nature. After a slow start, a more or less steep slope follows, which eventually flattens out again. In some colonies the curve is linear, so a straight line, without flattening. Still other colonies show an exponential curve, leading to an explosion of mites. Colonies with these kinds of curves drop out for propagation.

At some point of time in fall or early winter, the mite drop per day decreases. This is a sign that the brood nest is decreasing in size. The mite fall per day will remain low from now on until brood appears again in spring. The often used threshold value for chemical control of 1 fallen mite per day in December seems rather strict to me. In addition, this value does not take into account the size of the bee colony. After all, in a large colony more mites fall than in a small colony. That is why this threshold value is not very useful in practice.

In fact, each colony shows its own mite drop pattern. The issue now is whether these differences in mite drop patterns per day are indicative for the ability of the colony to deal with and survive Varroa. By now, we know from research that untreated colonies develop various mechanisms to survive Varroa.

The cumulative mite drop curves previously discussed are defined by a number of parameters: a_ = the curvature at the beginning of the curve; b_ = the deflection at the end of the curve; r_ = the rate of mite drop (in mites per day), i.e. the steepness of the curve; Y0 = the mite drop at the start of the count; and K = the maximum number of mites fallen.

Absolute (left) and cumulative mite drop (right) of colony 22-06 from 10/10/2022 to 26/12/22. Highest average mite drop was on 22/11/22. Parameter values of the curve are: a_=0,62; b_=066; r_=0,36; Y0=17; K=213.

Below, in a graph for 8 untreated colonies in my apiary, the values for (a_, r_) are plotted, with r_ on the horizontal and a_ on the vertical axis. All r_ values above 2 are bad in my estimation. Based on this assumption, at least the colonies 22-02, 22-05 and 22-08 are eliminated for propagation. The colonies 22-03 and 22-06 have a low a_ and a low r_ and are therefore eligible for propagation, provided they are also satisfactory in other respects, of course.

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Dark bee Landrace The Driest The Wageningse Eng

The year 2022

The mild winter of 2021-22 induced the colonies towards an early brood nest formation. However, in March and April the weather was cold and dry. This hampered colony development considerably. Consequently, the honey crop on the spring fruit trees was negligible. Still, it helped colony build-up.

In the late summer and early autumn, there was a severe drought once again. As a result, the heather honey harvest has largely failed. The autumn rains came just too late.

We had sown lupine on our field this year. More information on this crop can be found on the website of the ‘Golden Bean’ (in Dutch). There were many insects to be seen on the flowers, but interestingly enough few honey bees.

The autumn remained warm for a very long time, so the bees continued to breed until very late in the season. Fortunately, there is a lot of ivy around our field, so that pollen supply was not endangered.

However, the Varroa population build-up also continued for a long time, so that Varroa numbers in the colonies are still high at this moment, at the beginning of December. That means I will have to treat most colonies with oxalic acid, unfortunately. The Varroa population is determined by continuous counting of natural mite drop on the bottom board over a period of at least three months. A one-off count, as is often prescribed, is not sufficient, as the natural mite drop fluctuates strongly. By determining the mite drop over a longer period, a growth curve of the mite population can be constructed. The parameters that determine the shape of the curve give an indication of whether treatment is necessary or not.

The fertilisation of the purebred black queens at the Neeltje Jans mating station was disappointing. On average, only 60% of the young queens came back fertilised, but my result was even poorer than that… The first mating period had been called off: it was too cold and there were hardly any drones around. I had not prepared myself well for the second period, so that the selected breeder colony was not strong enough. This has negatively affected the quality of the young virgin queens. The fertilisation of the landrace queens on De Driest, on the other hand, was flawless: 100% fertilised. The difference could be that these virgin queens were not in small mating nuclei, but were obtained with the 2×9 method (see link).

As a result, the majority of the colonies now contain queens of the ‘landrace of the Wageningse Eng’. Only a few (fairly pure-bred) black queens remain.

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Beekeeping methods Dark bee Landrace The Driest The Wageningse Eng

The year 2021

Every year is different in beekeeping. This was no different in 2021. Spring started cold and remained cold. Consequently, there was no honey to harvest from the fruit trees. Contrarily to previous years, there were good rains during the summer of 2021. Very good for the Wageningse Eng, which is very drought-prone, as we know from experience.

The summer crop was average. I have to mention, though, that I haven’t migrated the bees to the lime trees this year and no doubt this has had a negative effect on the production.

On the plus side, the heather crop was very favourable this year. Thanks to the good rainfall in July the heather was in great shape. The ancient Dutch skep beekeepers knew that a wet July is a precondition for a good heather honey harvest. Temperatures in August were mild and the weather generally sunny.

Gathering Holland’s finest honey…

The transition of the colonies to the dark bee has been a priority this year. I have produced a fair number of pure-bred black queens, that have mated at the breeding station of Neeltje Jans. This mating station on an artificial island in Zeeland is run by De Duurzame Bij (The Sustainable Bee). There are only pure-bred drone-producing colonies on Neeltje Jans, which guarantees racial purity to a high degree (but maybe not completely).

Some 62% of the young queens I produced this year have been fertilised and went into egg-laying, slightly more than the long-term average. A lot of nuclei had to be produced to accommodate all these virgin queens, which required a lot of bees and hence has gone to the cost of the productivity of the colonies.

All in all, my apiary now has 75% of reasonably pure-bred dark queens. This is slowly becoming quite remarkable for Dutch conditions, for the dark bee is seriously threatened, here as well as in the rest of northern Europe, by continuous hybridisation provoked by introgression of foreign genes. Producing a 100% pure black queen, while at the same time avoiding inbreeding, remains a challenge and will require many more years of arduous selection.

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The Driest The Wageningse Eng

Cold spell in February 2021

We had almost forgotten about the cold in this country. The cold spell in February has changed the looks of the apiary dramatically. There is no harm for the colonies, provided food stores are sufficient. Because of the increased food uptake stores may become somewhat low in spring, though.

The snow has coaxed some bees outside. That meant sure death for them, and their bodies were lying scattered around in the snow. Were these the old winter bees, which left the hive to die outside? We will see in a month if the colonies have survived winter.

The apiary is getting emptier… The hives are standing outside now.

My new placement of the hives in small, loose groups. No more hives in long rows, in order to minimise drift among hives. In this manner, spread of Varroa is considerably reduced as well.

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The Driest The Wageningse Eng

Spring 2020 at De Driest

We’re experiencing an exceptionally warm spring this year and nature reacts accordingly. The colonies have clearly started breeding and are using up winter stores rapidly now. Therefore, I have given packs of sugar patty to a number of colonies today.

In our field we will be sowing barley this year, to be used for brewing our Wageningen beer.
Also, we will be sowing a flowering border again this year, this time with indigenous species and no longer the Tübinger mixture, as this contains too many cruciferous species to my taste.

Remains of mustard and wild flower border in February.

But first the couch grass must be removed and that’s quite a job for the wild flower border had been overgrown considerably by couch grass in recent years.

Removing couch grass before sowing the wild flower border.