Varroa project 2014 –>

Posted on April 22, 2017 by Erik

This test is accomplished and funded by LP:s biodling bee equipement supplier, Arne Andersson sideline beekeeper and Erik Österlund sideline beekeeper.

GOAL FOR THE PROJECT

The goal for this test is to see if it is possible:

to improve mite resistance in apiaries with 5-10 colonies,
to understand the impact of ”isolation” of 3-5 km (3-4 miles) to other beekeepers
to understand the role of small cell size in the broodnest
to see the role of differentiated treatment of varroa mites, that is treatment of only those colonies that exceed a defined varroa level

PLANNED MANAGEMENT

Avoid silent robbery

The colonies should be managed as similar as possible to a beekeeper that want to increase the number of colonies with an extensive management method. It should interfere as little as possible with the bees activities and avoid disturbing parameters, which could happen when you open the colonies often, like for example starting robbing in nectar droughts. It could be enough with silent robbery, a robbery activity that you don’t notice. That could be enough to destroy a test, in that the varroa populations are evened out

3% strategy

Therefore we decided to maximize the number of hives for the two main groups in this test to 10 hives (5+5). We also decided to make two or three alcohol washes with 1 dl of bees to monitor the varroa level during the season. When the Varroa level was higher than 3% we planned to treat with thymol. If it appeared wingless bees in or in front of a hive treatment was also to be performed.

Use of thymol

We decided to use dish cloth pads drenched with fluid thymol mixed with a minimal amount of rubbing alcohol (to lower the melting point of the thymol crystals) as treatment against mites when decision was made to treat. You can see how they are done and used in this article: http://elgon.es/resistancebreeding.html

Crop and feeding

If possible a harvest should be taken and sugar solution (or honey) fed at the end of season after harvest to ensure enough food for winter. The goal should be to leave a fair amount of honey for winter, if possible as much as you think your bees have got genetics to make it through the length of your winters.

Nucs and splits

Increase are made by making so called walk away splits that remain in the same apiary as the mother colony. These are allowed make there own queens, or supplied with mature queen cells made from a good colony in the apiary. This should also be the swarm prevention method.

Elgon and Carnica/Carniolan

We choose to use two different types of bees in the project. One type that has been selected for varroa resistance during many years, Elgon, that has been bred with this purpose since 1989. Another type that hasn’t been selected less, but in other traits are good, pure bred Carnica/Carniolan bees.

FITNESS

Increase of the number of colonies

The number of colonies wintered each autumn would be a way to measure the difference in success between the two parts (large and small cell size) of each main group, Elgons and Carniolans. To be counted in the increase would be the colonies that are brought out from the apiaries and the project, a kind of crop. What we measure will thus be the production of new colonies and survival of colonies to the next season, the difference of fitness. If colonies survive to the next season is not only dependent on the varroa and virus levels in the colonies, but also on other circumstances that influence the survival and how a colony thrive, for example other pathogens like nosema and quality of food like pollen throughout the season.

Start and number of years

Instead of starting the project with 5+5 colonies with each type of bees, we have choosen to start from a fewer number of hives and increase the numbers. And we plan to continue the project for at least 3-4 years. We have choosen areas for the test that are low in nectar and pollen sources. That’s also a reason why the number of hives are restricted to five in each part, which makes a total maximum for each type of bees 5+5 colonies, 5 small cell and 5 large cell.

CARNICA

Four Carniolan colonies, all of them being sister queens from a pure bred Carnica/Carniolan stock, were divided in two groups with 30 m between the groups. These groups were placed in a deeply forested area far enough from the Elgon bees. Here it was no farm in the neighborhood, like it is where the Elgon bees are placed. One group was established on Mann Lake’s standard plastic frame, 4.95 mm cell size. The other on Anel plastic frames with 5.5 mm cell size. Frame size medium (448 x 159 m). Hive type well insulated styren plastic boxes.

The Carnica bees 2014-2015

The Carniolan queens we received in 2013 were introduced into Elgon small cell (SC) colonies on 4.9 mm cell size shallow sized frames (448 x 137 mm). The Elgons are adapted to SC during many years and if nurse bees fed and born in SC should be of importance that criterium should then be met for this test. The Carniolans in their homeland could not draw and thus live well on ”SC”. Here they were adapted immediately through this process, but they could not draw wax foundation 4.9 well even though they lived well on 4.9. Probably because they were not genetically adapted to small cells. Mann Lakes 4.9 they could draw well. Probably because of the high plastic cell wall starters which they couldn’t remodel

In 2014 half of the Carniolans got only Mann Lake’s 4.9 (SC), half got Anels 5.5 (large cell, LC). During 2014 they were this way transferred to these two types of frames. Increasing cell size in the LC-group up to 5.5 was no problem either as they were adapted to 5.5 in their genetics before they came here.

All the Carnica/Carniolan colonies were treated with thymol in 2013, but not much, and in September 2014 after they were moved to their test destination. No DWV-bees were observed in 2014.

The LC part of the Carnica bees 2015

In 2015 in June the LC-group (both colonies) showed 6% varroa level and crippled winged bees, one colony quite badly. They both got one treatment with two homemade thymol pads with about 5 gr thymol each. The LC-bees gave no crop. The Varroa level had not increased again very much and was only about 1 %.

The SC part of the Carnica bees 2015

The SC colonies had 0.3% and 1% varroa level respectively. In beginning of June a so called walk away split was made from one of the SC-colonies. The new queen then of course mated to very closely related drones.

The strongest SC-colony gave a small crop.

In September the SC-colonies still had only around 1% Varroa level. None of the colonies got any treatment in the autumn due to the low varroa levels. The SC-colonies thus got no treatment at all in 2015.

The Carnica bees 2016

The LC part of the Carnica bees 2016

The weakest of thee LC colonies didn’t make it through winter. The second one looked fine in May.

The weather was then rainy and chilly for several weeks, and when the beekeeper returned in late May to monitor varroa levels, in the remaining LC-colony he only found some dead brood and a few dead bees on the bottom.

The SC part of the Carnica bees 2016

In spring 2016 the now three SC-colonies were doing fine, two of them though small in size.

In the three SC-colonies the varroa levels were 3-4% in late May and some crippled winged bees appeared. Thymol pads were applied in June. A walk away split was made from the strongest SC-colony. The weather was unfavorable and the other three robbed the split. It thus died.

In September the three SC-colonies looked fine and got no treatment. The bees superceded the three year old queen.

The Carnica bees 2016-2017

The three SC-colonies were moved to an apiary with better resources for nectar and pollen. Some more pure bred Carnica queens were received in 2016. They will be used to biuld up the test apiaries again. Daughters will be bred from these and mated in the apiary with drones from the survivor colonies of the SC bees.

The whole season of 2016 was bad in producing nectar and pollen. The colonies had a hard time growing in size. It was late in the season when complementary feeding in preparation for winter was done that they grew somewhat in strength. That was the reason these bees were moved to a better place for food.

All three colonies actually were weaker than wanted going into winter. Two colonies made it through winter. The third and weakest died. This colony had probably survived if it had been fed honey (or fondant) and pollen during the worst nectar- and pollen drought periods.

ELGON

Six Elgon colonies of two different mother lines divided in two groups with 3 colonies each were set up. These groups were placed in a deeply forested area with a small farm in the neighbourhood. The two groups were placed about 700 meters from each other. One group got Mann Lake’s standard plastic frame with small cells (SC), 4.95 mm cell size. The other got Anel plastic frames with Large cells (LC), 5.5 mm.

Two sister groups were used. One sister group consisted of 4 queens, 2 SC and 2 LC. The other sister group had two queens, 1 SC and 1 LC. Frame size is medium, (448 x 159 mm). Hive type with well insulated styren plastic boxes.

The Elgon bees 2014-2015

The Elgon groups were established with new queens in 2014 and transfered successfully to Mann Lake’s 4.9 and with big difficulties to Anels 5.5.

The queens in the LC colonies were very hesitant to lay in their large cells. One queen totally refused.The broodnest of that queen consisted of only two shallow SC-frames. The resulting colony was of course small going into winter in 2014, but it wintered together with the other two LC colonies in their test apiary.

Most of the colonies, SC and LC, were treated in 2014 with thymol but mostly only in May. So this Elgon test groups of 3+3 were not managed in regard to the Varroa mites, similar to the Carnica groups. In the Carnica colonies the varroa populations were evened out between them, by treating them with home made thymol pads in September 2014.

The Elgon test colonies were taken from different apiaries and the varroa level in the colonies were not known when they were brought to the test site in late August. Earlier in 2014 the colonies who had wingless bees were treated with thymol, in May that was.

The LC part of the Elgon bees 2014-2015

In spring 2015 the Elgon LC group continued to create problems as the bees protested against using LC combs for brood by supersedure their queens, probably in an adaption process.

In April before grafting time and any drones were flying one LC-colony was queenless. The new virgin queen had of course failed to mate and was gone. I combined the queenless colony with the mini colony (the one with the queen that had refused to lay but in the two shallows). This queen still refused to lay in any other comb than the two shallows, so I tried to fool them by giving them a couple of 5.3 mm cell sized plastic frames on each side of the SC combs. That worked. When the 5.3 were filled on each side of the 4.9 they started on the 5.5 next to the 5.3.

It seems it is the workers that prepare the cells for laying, not the queens that are deciding in which cells to lay. (This experience is also in line with what is written in old books from beginning of 1900, that when broodnest have 5.1 you could use 5.6 in honey supers without excluder as the queen didn’t lay in the 5.6.)

In late April 2015 the third (now the second as the other two were combined) LC-colony had a virgin. They were also trying to supersedure their queen. No drones available yet. So she failed. The colony got a queen cell in second half of May. That queen got laying. This colony had 5% varroa level in August and got thymol.

The first colony (former first and second combined) got a small piece of thymol (actually both parts that were combined got half a piece each) early in spring to help against eventual patoghen problems as they had different kind of problems (weak but queenright and queenless). This colony showed only 0.3% Varroa level in August and got no treatment.

The SC part of the Elgon bees 2014-2015

In 2015 the three Elgon SC colonies developed well. Splits were made from two of them. One failed, but finally got a laying queen very late in season. It ended up weak. It was lost during coming winter, the only loss of the Elgons. The smallest of the overwintered colonies had a queen that was laying badly. It was killed and replaced by a ripe queencell.

Four of the now five colonies showed crippled winged bees in July and had Varroa levels between 2-7%. Even the 2% colony showed a few DWV-bees telling me the virus levels in the colonies were quite high. One 3% had no DWV, the weak one mentioned above and it was the only one that didn’t get treatment.

Because the varroa populations in the colonies weren’t allowed to grow strongly (still there were enough viruses in 2015 after years of somewhat higher varroa and virus pressure in the Elgon apiaries of Erik Österlund), the virus amounts in the colonies decreased and also there was no silent robbery. And the varroa populations were evened out at a low level. Thus the situation now was much more comparable with the varroalevels in the Carnica colonies in autumn 2014

The Elgon bees had better nectar flows than the Carnica in 2015 and the Elgon colonies gave a good crop from the Heather in 2015. The average crop was about the same for both SC and LC colonies. In August none of the SC Elgons had above 3% varroa level. They had 0%-3%, and got no more thymol. No colony swarmed in any of the test apiaries.

The Elgon bees 2016

In spring 2016 one of the Elgons, the very weak one in the SC-group died (as mentioned above). Both LC colonies survived.

The LC part of the Elgon bees 2016

In the LC-group splits were made from both colonies. Weather was bad and one failed to produce a laying queen. It got a new ripe queen cell. The parts with the ”old” queens (from the year before) both superseded their queens, in line with experiences in 2015. This year they waited until beginning of summer when there were drones around. Maybe the bees had adapted somewhat to LC now.

The season of 2016 was very bad so no crop was secured from the LC-group. In spring the varroa levels were 0.3% in all four colonies (they became four after splitting in late May). In early September it was 0% – 8.6% – 0.9% – 4%. The two with highest levels were treated with thymol. The other two not. We can see that two colonies had very low levels of Varroa mites. This indicates a good genetic set up for Varroa resistance, also to be able to work with large cells apparently. The queens in the colonies with low Varroa level are sisters, mated in the test apiary. They are daughters to one of the colonies in the apiary, one in a split. The other as a result of supersedure in the mother colony producing this split.

The SC part of the Elgon bees 2016

The four remaining colonies in the SC-group gave a split each. Season was bad and two of the splits failed. A small crop was secured from the strongest of the colonies.

The two colonies with two year old queens supersedured these later in season. The 6 colonies all had 0.3% varroa levels in spring. In August the varroa levels were between 0-1.7%. As we had decided not to keep more than five colonies in each of the four parts of the test, colony no 6 of the SC-ones (the one with 1.7%) was removed from the test area. It wastreated with a small amount of formic acid to get an idea of the mite load and also test the shaker method. It fell 10 mites in a couple of days. The other 5 colonies remaining at the test site didn’t get any treatment.

The Elgon bees in the beginning of 2017

All four colonies in the LC group wintered well, in spite of that two of them were almost too weak, those that had had the highest Varroa levels and been treated.

One of the five SC colonies defecated a lot on the outside of the hive, though not much inside. They did not have a large amount of honey left for winter the previous autumn. And it was of good wintering quality. The winter before all colonies had had a large amount of difficult winter honey, from heather. The colony that died was the strongest and smallest Varroa level. It measured 0% on 400 bees. The was a good amount of food left in the hive after it had died. The colony had an old queen, and just a few meters there had been quite some traffic during late winter from a tree harvester. The other colonies looked fine, with almost no defecation.

Harvest and Varroa level 2015 and 2016 in SC and LC parts of the Carnica bees. The sites for Carnica and Elgon bees are not comparable as the Carnica site was didn’t have the same amount of food sources. Click on the picture to get it bigger and of better quality.

Harvest and Varroa level 2015 and 2016 in the SC and LC parts of the Elgon bees.

RESULTS

Losses

The losses in the Elgon groups have been quite normal, on the lower side. It has in percentage been higher in the Carnica groups, especially among the LC bees. The higher amount of losses can be explained by the low availability of pollen and nectar, especially during 2016. That’s why the test site for the Carnica bees has been moved. One conclusion is that during times with small amounts of available pollen and nectar a solution could be to feed the colonies fondant/honey and pollen to develop healthier and stronger colonies better adapted to survive winter.

The strategy of 3 %

The strategy to measure the Varroa level a couple of times during the season and use Varroa treatment (dish cloth pads, about 50 x 58 x 1.5 mm [2”x2”x1/16”], drenched in thymol) when/if the Varroa level is higher than 3 % (only treatmnent in these colonies, not in those below 3 %) has minimized reinfestation, maybe altogether. You thus get a true picture of the Varroa level in the colonies and thus a better selection of the most resistant colonies and the most susceptible ones. You could for example have expected that the different cell size groups had affected each other so that eventual difference in the varroa levels had evened out, especially among the Carnica bees as the two groups there were only 30 m apart.

Little need for Varroa treatment

Relatively little of Varroa treatment has been used, probably partly explained by the absence of reinfestation, no silent robbing. Most treatment has been used in the LC colonies of both the Elgon (2016 when reinfestation had been removed) and Carnica (2015, in 2016 there was no LC left) colonies.

The strategy of 3 % seems to have eliminated the need of Varroa treatment in the SC part of the Elgon bees due to elimination of reinfestation and enough good development of the varroa resistance with the Elgon bees.

This strategy has also lessened the need for varroa treatment to every second year with the SC part of the Carnica colonies and the need for treatment then has been small. Thymol in this context has been effective.

Cell size and fitness

In the LC part of the Carnica bees the need for treatment has been bigger probably because of a quicker development of the Varroa population. It seems fitness has been lower here probably partly due to the bad pollen and nectar availability. But fitness may also be lower because of other reasons. The Carnica LC colony that died in May did not die due to high varroa level. Lack of protein and/or other pathogens (like nosema) can be the cause. The Carnica test site is moved to a place with better food sources.

One can object to this conclusion of lower fitness for LC bees because the number of colonies are low.

On the other hand were all original queens in the Carnica group sisters and all colonies in SC and LC groups (Elgon and Carnica) are behaving consistent in this respect. And any difference in fitness between the two cell size groups among the Carnica bees should have been to the advantage of the LC colonies because the SC colonies had become inbred. Usually follows a lower immune system with inbreeding. Possible impact of this small distance would have been small(-er) difference in the varroa levels between the two groups due to evening out of the varroa populations. The 3% strategy, measuring varroa levels and treatment when it was above 3%, lowered the varroa populations enough to eliminate (totally or enough) the silent robbery.

In 2016 the only colonies that needed treatment were in the LC colonies of the Elgon bees. It should though be noted that with a stock of bees that have been selected for Varroa resistance it is possible to find colonies that are resistant also on large cells. Two colonies (with sisters queens) had very low levels of Varroa mites.

The honey crops, the bee strength of the colonies indicates, and the resulting number of colonies in the SC and LC parts of the stocks of bees indicates that it is no disadvantage to use small cells in the broodnest, rather the contrary.

Summary of production of new bee colonies, increase in the number of wintered bee colonies. These figures could be seen as a measure of the vitality of the different cell size groups. There is a difference to the benefit of SC bees both in the E group (Elgon bees) and the C group (Carnica bees). Click on the pictures to get them bigger and of better quality.

Suggestion on a breeding program for increasing Varroa resistance in a bee population. The background for these suggestion is the results of this project, so far.

Reworked website with new info

Posted on December 26, 2016 by Erik

Hello dear beekeepers!

I’ve been reworking my old website. not my blogs. The English part became ready enough to be published and I launched it on http://elgon.es

There are quite some new material there. In the article “Resistance breeding” some of the experiences from 2016, very positive and quite important experiences. On that topic there will be more info later on.

This website is so called responsive, which most are these days. It means that it automatically adapt to different screen sizes, down to that of a cell phone. It’s made with and easy working and free app called Rocket Cake.

Lasting learning?

Posted on October 3, 2016 by Erik

In one of the recent blogposts I wrote about non-resistant bee colonies against varoa mite, learning from resistant worker bees how to deal with the mites and being resistant. It seems now that these colonies that has learned resistance have to have worker bees from genetically resistant colonies drifting into them continuously to stay resistant.

This resistance went on for at least a couple of years. I referred to experiences of Hans-Otto Johnsen and Terje Reinertsen (http://www.elgon.es/diary/?p=880)in Norway and Magnus Kranshammar (http://www.elgon.es/diary/?p=890)in Sweden.

A.) In the Norwegian cases colonies with queens from non-resistant stock originally were kept in apiaries together with resistant bee colonies. Bees are kept on small cells.

B.) In Magnus’ case it was somewhat similar as the colony of the original queen, which was the result of genetically selected resistance, and splits from it with queens of originally non-resistant stock, were kept in the same apiary. The total number of colonies was not big here. These bees were kept on large cells.

A.) A couple of years ago Hans-Otto started a variety of the first tests he made mentioned in the blogpost above. He introduced virgin queens of non-resistant stock into splits from his Elgon-stock. In this test he didn’t place these new colonies in apiaries together with his resistant stock. Instead he placed them in an apiary of their own in the forest, a lot more than 2 miles (3 km) from other bees. For two years these colonies functioned without problems concerning Varroa.

This autumn they all showed crippled winged bees. He made a test with the Bee Shaker (http://www.elgon.es/diary/?p=794). About 35 mites from 300 bees. 11-12% Varroa level. Probably there was resistance in the colonies at least the first year as long as the old worker bees were alive.

In an apiary all colonies will share more or less worker bees with each other. The whole apiary works more or less together. This depends of course also on how much worker bees from different colonies drift. In an apiary with resistant colonies, bees from resistant colonies will help keeping non-resistant colonies resistant. (And if the non-resistant colonies are many compared to for example a single resistant, this may create problems for the resistant one.)

B.) Two splits from a colony with a queen of non-resistant stock, which anyway were resistant, were moved to an apiary of their own in a forest about 2 miles (3 km) from other bees.

The mother colony of the splits was kept in the same apiary as the colony with a resistant queen (which was still alive this year). It was this resistant queen’s colony that gave bees to this mother colony of the described splits. So you could expect some drifting had occurred with resistant worker bees now living in the colony with the non-resistant queen. Thus some good resistant worker bees were living in the splits as well to begin with, until they died their natural death.

Drones from the non-resistant queen of the mother colony of the splits were of course present in these. But of course there were also drones in some colonies 2 miles (3 km) away. Those colonies were of Elgon heritage, but not of the very best variety of resistant stock. The splits got virgin queens from an Elgon colony of good resistant quality. The Varroa level was initially very low in the splits, about 0.3% (without treatment this year or the previous year).

The splits developed very well after the queens were mated and laying. In the beginning of September the Varroa level was 2% and 3.3% respectively. It had increased more than expected, but was not alarmingly high. The cell size in those splits was initially 5.4 mm, that is large cell size. (Resistant thus in spite of the large cells.) The story of those bees are told here: http://www.elgon.es/diary/?p=890. But the virgins came from established small cell size colonies since many years. The plastic combs used for increase were small cell. The 3.3% part had relatively somewhat more left of large cell combs.

One of the splits in case B. The original large cell combs are of an old Swedish (as well as an American) size, 12”x12” (30 x 30 cm). With the help of adapters these combs are placed in boxes which hold Jumbo sized frames (448 x 286 mm) plus a deeper bottom board. The combs used for increase are small cell plastic Langstroth from Mann Lake (http://www.mannlakeltd.com/beekeeping-supplies/category/page19.html).

C.) In a project that has been going for a couple of years now, one apiary was placed a lot more than 2 miles (3 km) from other bees. The queens were of non-Elgon, non-resistant, large cell bees. They were introduced into Elgon colonies on small cells in 2013. In autumn 2014 they were moved to their test apiary and treated with a small amount of Thymol to ensure an in the test initially small and quite even population of Varroa mites. They had during 2014 been standing in apiaries with Elgon colonies. Thus probably containing some drifted Elgon worker bees. The test apiary was poor from a nectar point of view. In 2015 the Varroa level in autumn was low, around 1%. A split was made during 2015 and queens shifted to daughters made in the split in two of the units. The virgins were mated in this apiary. One of the originally queens, all had been sisters initially, were still left in its colony. The new queens were of course very inbred as the available drones were very closely related to the virgins.

In the middle of the summer 2016 the Varroa level was 3-4%. A couple of weeks later all three colonies showed crippled winged bees. They were treated with two pads with 5gr Thymol each (once) after which they recovered.

Conclusions

The experiences given here makes it probable that there are more than one component necessary for a queen of a non-resistant stock to have a resistant colony. First the colony with a non-resistant queen must become resistant. It can become resistant quickly in two ways. (One may ask whether it is desirable to deliberately do this.)

1.) Worker bees from a resistant colony can be united with a non-resistant colony through shifting the places of a resistant and a non-resistant colony. Most of the other colones in the apiary are resistant. It is uncertain how many of the colonies that should be genetically resistant.

2.) Splitting a resistant colony and giving the split(s) virgin or laying queens of non-resistant stock.

To maintain this resistance achieved, still with a queen of non-resistant stock in the colony, when the first resistant worker bees that came along with the splits are worn out and dead, new resistant worker bees have to come into the colony in some way. (Resistant worker bees are bees in colonies that show resistant behavior to such an extent that their colony can rid themselves of mites through different kind of hygienic traits.) It seems the number of resistant worker bees needed to come from other colonyies “per time unit”, are not very many. By just keeping the colony in an apiary with resistant colonies this seems to be achieved, probably through drifting of worker bees between the colonies in the apiary.

In all cases above, A, B and C there were no new resistant worker bees drifting into the colonies. In case B though virgin queens from a resistant queen were introduced, but no new bees from the original resistant stock were re-introduced. Instead new workers with probably better genetic set-up for resistance were born. But there were now probably no, or very few, resistant worker bees left that could teach newborn bees. At least this is a conclusion that is close at hand, to explain the increase of the Varroa level. It will be interesting to see what will happen further on in these two colonies. Hopefully the virgins were mated to other drones than those that came along in the splits from the genetically non-resistant queen.

No shortcut

It is thus no shortcut to get resistant bees, to split genetically resistant colonies and introduce whatever kind of queens into those splits (of non-resistant heritage)! What these experiences tell us is how important it is to increase your number of colonies and replacing the dead outs by splitting the best resistant colonies. The very best might many times be to let those splits raise their own queens. And in addition to this breed queens from good resistant colonies of good heritage in being resistant.

Small cell size important in breeding Varroa resistance

Posted on July 30, 2016 by Erik

After reading the blogpost ”Breakthrough?” an European PhD-Scientist wrote me an email with the following comment:

”After reading your post I realized that you do have small cell size, but you’re not mentioning it in the actual post. To make sure that the reader’s get the full picture, the main components of your management system, this should be explained for them.

For instance, for me it’s a fact, that the cellsize used in a selection program is a factor incorporated in the population just like springfeeding appears to create a dependency of that feed to make bees start an explosive spring behavior.

As our bees are still wild animals, you can select whatever you like (or forget to see as selection-factor) to specialize your bees. Feel very good that your selection works.

But looking at the picture I have, some more ’vitality’ comes with better Varroa control. More or less ’Race’-independent. Question for me: ’slight inbreeding effect’?”

A valuable comment which gives food for thought. Thanks!

Small cell size (SC) is so natural for me, that it’s the normal thing. I forget it sometimes. Those small quick bees flying directly into the entrance are what I expect when looking at a bee colony.

It’s interesting Eric Erickson in Tucson when he started his breeding project for Varroa resistance found that many survivors that he used in his program were on 5.1 mm cell size. This was quite smaller than the most common 5.4 mm. http://www.elgon.es/diary/?p=457

Eric Erickson when I and Hans-Otto Johnsen visited him and Lenard Hines about ten years ago talking Varroa resistance.

Erickson is said to have been forced to retire earlier than he should have. He died earlier this year (2016) well above his 70th year. There were nice obituaries, but I couldn’t find a word about his Varroa resistance program. Strange.

Every spring since I started to take my bees down to small cell size, when I took care of the dead outs after winter I saw that many combs were poorly drawn. The bees had many times failed to follow the 4.9-pattern and drawn patches of sometimes bigger worker cells and sometimes a lot of drone cells. Also when managing struggling colonies during the season the same observation was many times made. This year very little of this was seen. But I still have some colonies that can’t follow the 4.9 pattern when drawing their own combs (but they do well on already drawn small cell combs, especially colonies with heritage from queens from other beekeepers I have found interesting to try.

At the same time I’m aware that there are beekeepers that havn’t treated against Varroa for many years that still use large cell sizes. I draw he conclusion that it is possible to keep bees on large cell size and still be treatment free. But I see very little reason for not going down in cell size. The most important reason is that the bees themselves go smaller when given the chance. It must have something to do with their fitness and survival, not actually in first place in relation to Varroa.

Concerning the earlier blog post “Breakthrough?” and that I have used very little Thymol this year. Last year at the end of July I had used Thymol on about 70% of the colonies. This year at the same time of the year I have used Thymol on 2 colonies out of about 150 (I had about 150 last year too). I find it hard to believe that the only reason would be a successful breeder queen. I think better pollen availability this year has given a better immune system. And reinvasion I think is less problematic. With the latter in mind, I can imagine that adaptation to better control the mites is developing in the bees. And the absence of chemicals, in this case thymol, do not disturb this adaptation.

Another change in management is that I don’t move bees between apiaries. When making splits they stay in the same apiary. If there’s only one colony in a yard I split that colony and build up the apiary again this way (from now on). Some minor movements of bees have been done though.

Struggles for the survival of honey bees

Posted on June 6, 2016 by Erik

SB is a relatively new and dedicated beekeeper in southern Germany. She is interested in different kinds of bees and their place in the ecological system. I asked her to tell her story and her struggles helping her bees to survive and thrive on their own as much as possible without chemicals. She writes:

After watching wild bees for some years I wanted to have honeybees and took lessons given by an organic beekeeper. In the year 2014 I bought my first colony from him. It was a Carnica cross on natural comb, built by the bees without the help of wax foundation. They had been treated with oxalic and formic acid against the varroa. But they were sick anyway!

My first colony was a Carnica (Carniolan) colony on natural comb.

I tried to find a way out of this chemical strategy that seemingly didn’t help. I got some information on internet and started watching how bees defend themselves against illnesses. I don’t want to have them close to other bees. I tried to help them with sugar powder dusting to rid them of the mites sitting on bees. After treatment with formic acid in summer, they had a natural downfall of 30 mites per day. After sugaring the whole hive ten times with 2 days in between the natural downfall of mites were 5 per day. This involved a lot of work and still didn’t do the job. The bees had chalk brood too!

I measured cell size on their natural comb. It was 5.0 mm in the brood area, 5.4 in food area and drone cells began at 5.6. All honey was taken when harvested, so they lived on sugar syrup for a long time of the year. They died in february 2015, not having enough bees to warm the hive!

The AMM queen

I had found some contacts through internet and was able to get 4 hives in 2015 which weren`t treated with chemicals for some years. One was of the dark bee Apis mellifera mellifera (AMM) , three were Carnica (Carniolans). I made some splits and wintered 3 of the AMM origin and 5 of the Carnica origin.

The former owner had a crisis being the victim of a migratory beekeeper whose hives most probably caused reinfestation bringing a lot of mites into his hives. He overcame this crisis combining the weakest of his hives, so they became strong enough to defend themselves. Some survived. In some of these he introduced a AMM variety of queens that had a reputation of being more resistant.

My aim was to follow Dee Lusby`s in Arizona way of beekeeping as much as possible (http://beesource.com/point-of-view/dee-lusby). Using small cell foundation, leaving with the bees enough honey for food, using so called housel position of the combs, what she calls unlimited broodnest and using no treatment (if possible).

Now I have 11 colonies and high hopes.

All 8 hives survived winter, but in spring 2016 I had to eliminate one of them because its bees were too susceptible to virus (another than DWV). I have made some splits and have now in May 11 hives and high hopes. The bees are my teachers. I want them to survive.

The AMM I have are showing hygienic behaviour against mites in the brood. Now I have seen it also in my Carniolan crossings (the picture).

I don’t do drone brood cutting as I want the mite to continue being a drone parasite in first place and not a worker bee parasite. I’m happy to see more and more of hygienic behavior against the mite, also in drone brood. Now also in the Carniolan crossings.

At last I want to quote Kirk Webster (http://kirkwebster.com):

“Beekeeping now has the dubious honor of becoming the first part of our system of industrial agriculture to actually fall apart. Let’s stop pretending that something else is going on. We no longer have enough bees to pollinate our crops. Each time the bees go through a downturn, we respond by making things more stressful for them, rather than less – we move them around more often, expose them to still more toxic substances, or fill the equipment up again with more untested and poorly adapted stock. We blame the weather, the mites, the markets, new diseases, consumers, the Chinese, the Germans, the (fill in your favorite scapegoat), other beekeepers, the packers, the scientific community, the price of gas, global warming – anything rather than face up to what’s really happening. We are losing the ability to take care of living things.”

We are at big risk losing the ability to take care of living things. Thank you everyone who is helping me to improve myself as a beekeeper.

Learning and teaching

Posted on April 4, 2016 by Erik

Hans-Otto Johnsen was very skilled already in his youth keeping old American cars and trucks going. That skill can be very handy for a commercial beekeeper.

For many years he worked as an expert on explosives, but he got poisoned by nitroglycerine and had to change his job for making a living, so he turned to beekeeping.

At the university

For a number of years he worked as a technician under Prof. Stig Omholt in Norway and at the same time developing his commercial operation. His experience from these years has helped him in developing his Varroa resistant bee stock.

A good brood comb in one of his Norwegian type of combs before he switched to medium Langstroth size.

Quite soon he got to know me and wanted Elgon stock to work with. He imported quite a number of splits from me. He kept track of the Varroa levels in the colonies and stopped using any type of chemical to fight anything in the hives. He wanted his bees to develop their ability to survive, which they did.

Ed Lusby and Hans-Otto discussing small cell beekeeping at a fuel filling stop on our way to one of the apiaries of Lusbys’ in the Sonoran desert.

In America

We travelled together several times to America and studied small cell beekeepers and wax foundation producers. Hans-Otto bought equipment and started producing wax foundation, small cell and large cell as well as different sizes of drone foundation. His mechanical and engineer abilities showed themselves to be very useful as he changed and improved the equipment, for example the cooling of the drum for producing rolls of uniform sheet for feeding the plain and foundation rollers. Also the setup of plain and foundation rollers needed according to his opinion more controls of individual speeds for different parts of the production process, which he included in the setup.

Hans-Otto and Gary Dadant discussing wax foundation production during a visit with Dadant’s in Hamilton.

Research

He started to plan and set up different tests for looking at the effects of different cell sizes in brood combs and to produce virus free drones to mate with virgin queens. He saw that bees easier recognized (and removed) when drone brood was infested with mites when these cells were smaller, which they naturally are with smaller worker brood cells. He also saw that mites more readily infested the biggest drone cells.

He was involved in small cell tests, of his own and together with others. One can be found here: http://beesource.com/point-of-view/hans-otto-johnsen/survival-of-a-commercial-beekeeper-in-norway/

Today Hans-Otto has research money from the Department of Agriculture in Norway.

Resistant stock

He developed his bees in quite isolated areas, but not totally isolated, so sometimes the bees were mated to carniolans, buckfasts and the native brown bee (Mellifera mellifera). He also worked together with Terje Reinertsen, another Norwegian beekeeper, very similar to him when it comes to beekeeping. They exchanged breeding material. Both of them have discovered that their bees teach other bees how to get rid of mites. It seems this ability to teach new bees is very important knowledge when developing a Varroa resistant stock.

Today Hans-Otto hasn’t treated his bees for 15 years. The levels of mites are normally very low in his and Terje’s colonies and he never sees any wingless bees. In 2014 the bees of Terje were tested for Varroa levels by the Norwegian Beekeeping Association in preparation for planned research. (Birøkteren, vol 131, 2015(1), pages 13 and 24. The Bee Journal of the Norwegian Beekeepers Association.) The levels were so low it was difficult to calculate the reproduction rate.

When Hans-Otto moves his bees to the heather in late summer, for producing heather honey, his bees quickly pick up quite some mites. The natural downfall of mites will then be higher until about a month before the frost will make the bees form winter cluster. Then the downfall is almost zero again.

Book contribution

In 2010 Georgia Pellegrini (https://en.wikipedia.org/wiki/Georgia_Pellegrini) published her first book on natural food: Food Heroes (http://www.amazon.com/Food-Heroes-Culinary-Preserving-Tradition/dp/1584798548) She included a chapter about Hans-Otto and his focus on natural production of honey. For example he concludes that small cell bees are more biologically optimized than large cell bees. Thus research done with small cell bees are more reliable concerning what bees are and how they react naturally. In short, research results with small bees are more reliable.

In this context it’s interesting to notify that Norwegian wax is almost pesticide free.

An important part in his quality control is producing wax foundation as he thinks will be the best help for the bees.

Learning and teaching

Today we understand that adaptation of bees to fighting Varroa isn’t only selection breeding, natural or beekeepers’, for changing the DNA composition, but also epigenteic adaptation, the change of expression of the DNA as a result of changed environmental pressure on the bees. This turns the focus to the importance of locally adapted bee stock. Now research is going on with a third adaptation step, how bees learn how to deal with challenges and how they pass on this knowledge to other bees, worker bees to worker bees.

Hans-Otto caught a carniolan swarm of not resistant large bees that choose one of his swarm traps for their new home. After establishing this swarm in one of his apiaries he shifted its place with one of his resistant colonies. So this nonresistant colony received the field bees of a resistant colony. Afterwards they both behaved like resistant colonies.

One year he bough buckfast virgin queens not selected for Varroa resistance. He put them in splits made from his bees. The virgins mated in his apiaries. These splits were spread out in different apiaries of his. For two years they kept their colonies working fine and resistant to mites as good as his other colonies.

Now these two experiments absolutely are food for thought.

More than15 minutes of fame

Definitely Hans-Otto Johnsen is worthy of more than the 15 minutes of fame, one commentator thought was enough.

Cell size affects water content

Posted on October 26, 2015 by Erik

I started taking down my bees to small cell size 15 years ago. 10 years ago I had combs with 4.9 mm, 5.1 mm and 5.4 mm cell size in the supers. At one time I did some measurements of moisture content in honey from the capped cells in supers.

The supers were square sized for 12-frame Shallows. Single walled wood, not very thick to keep the weight down. Almost all my supers are like that. I measured moisture content in honey from cells close to the top of the frame, in the middle. When comparing the different cell sizes in the same box it was done from two frames, comb sides next to each other.

What I found then was that the moisture content in the center of the box was 1% lower than from the outer combs. This was the case when all combs in the super had the same cell size. I speculated that this was due, at least partly, to the fact that the uninsulated walls of the super made the temperature vary more in the super during day and night, especially close to the walls. During nights water drops could well be formed on the outer frames. And the honey could thus take up more moisture.

The moisture content was then 1% lower in cell size 5.1 than in 5.4. And it was 1% lower in 4.9 compared to 5.1.

The moisture content was so low in the smaller cell sizes that I became braver to harvest combs that were not fully capped. I started harvesting whole boxes even if the outer combs was not fully covered or even 2/3 covered. Sometimes outer combs were and also are today only capped at the top. Shallow frames are low, 137 mm, so it will not be as large area of non-capped honey compared to a higher frame where only uppermost part of the honey is covered.

Water content in my honey is usually around 16-17%, rarely above 18%, sometimes below 16%. Before I used small cell size, moisture content was often around 18%, even though I tried to harvest only capped honey.

Project with plastic frames and insulated boxes

This year (preparations began last year) we (I and two others) started a project to test a number of different things (will probably come back with a report). The project uses insulated plastic foam supers for 10-frame Medium frames (159 mm high). All frames are supposed to be plastic with plastic foundation. Two different cell sizes are used, 4.95 mm and 5.5 mm. Thus a group of colonies have only 4.95 and another group 5.5. Not all combs are completely that way in all colonies. Next year it will.
Yellow plastic frames with 4.95 mm cellsize and black with 5.5 mm.

Low moisture Heather honey

This year cell sizes were somewhat mixed for different reasons, especially in supers. So when I harvested a number of supers with well capped Heather honey combs with different cell sizes in the same super I took the opportunity to measure the moisture content again in a similar way as 10 years ago.

This time, I could compare 4.95 with 5.5. And 5.3 with 5.5 (I had some plastic frames with cell size 5.3 also for a certain reason I will come back to in the report to come).
The notes I had from the test 10 years ago I have not found. But I found those I made this year. They are seen in the table.

Super	4.95 mm	5.3 mm	5.5 mm	capped honey	uncapped honey
1	16.0%		17.0%	X
2	16.5%		17.5%	X
3		16.0%	16.2%	X
4		17.0%	17.3%	X
5		15.9%	16.0%		X

Similarities and differences

The tendency that smaller cell sizes means less moisture in the honey holds. But the differences between cell sizes are smaller this time. Another difference is that the difference between the middle frames and the outer ones in supers with the same cell size was not found now with well insulated supers.

The difference between the cell sizes are greatest when 5.3 and 4.95 are compared. The difference between 5.3 and 5.5 was not as big (not per 0.1 mm cell size either).
The moisture content was for me surprisingly low considering that it was almost pure heather honey in the combs checked. Usually Heather honey has higher moisture content, probably due to it’s gathered late in season when temperature difference between day and night is bigger. But it was unusually warm in August this year when the Heather was in bloom and remperature was not very low in nights.

When trying to understand the results I think it helps being aware that when bee colonies build their own combs without the help of foundation many have observed they build (when they are adapted after a period of perhaps several years) mostly between about 4.7 and 5.1 mm cell size in the brood nest and 5.2-5.5 (approximately) in honey area.

When the bees have collected a lot of honey for the winter period, most of the empty cells are small. When spring comes the first brood is reared in small cells. Low moisture honey is closest to brood then. Is that of any importance for the bees? Later in season some brood is reared in slightly larger cells as well. Towards the end of the season the queen lays almost only in small cells again.

Free bees

Posted on June 19, 2015 by Erik

This year is a year of swarms in Sweden. The weather is chilly and damp. Bees are sitting a lot inside having little to do but making queen cells. Maybe like many others in such a situation, thinking of reproduction.:)

In my home yard I have up till now have hade one swarming attempt, which I stopped with rain from my garden hose.

During this week I’ve had two swarms flying into my home yard from my neighbor beekeeper less than half a mile away (half a km). He has Elgon bees as well, but a smaller frame size than me, which I think contribute to increase swarming.

The first one flew to the pile of boxes with crap combs, but couldn’t get in. http://www.elgon.es/diary/?p=722 I opened up after discussing with them. They behave well, even when I pass very close to them getting things in the container. The pile sits in the opening of the container and the door is always open. After a couple of weeks I will move those boxes where the bees reside to another yard.

The bees liked the box better than the pallets.

A couple of days ago another swarm flew into my garden and landed on a pile of pallets. Another bad place. With the help of may hand I scooped most of the bees into a swarm box and put it on top of the pallet pile and hope the bees would like the box better than the pallet pile.

I hived the swarm from above, easy and quick.

And they did. In the evening all of the bees were sitting still in the box. I hived the bees in two square shallow boxes. Corresponds to two 10-frame mediums. Now they are doing fine.

Church bees.

Yesterday I got a call from a church in the north part of my little town. A big swarm had landed the day before. They wanted me to remove it. It must be Abbey bees I concluded, Buckfasts. And they behaved well. A biig swarm. Probably from my friend Karlsson about 1 mile away over the fields. Elgons too.

I climbed the ladder, held the box in my left hand and scooped again most of the bees with my right hand into the box, and hanged it on the gutter, hoping that the rest of the bees would gather into the box through the excluder.

In the evening the bees were inside the box ready for transport to their new home.

The bees had in one day drawn 5 small combs with cellsizes 5.0-5.4 mm. 5.4 at the top and 5.0 at the bottom. Some nectar in the top of the biggest and two eggs. Laying queen:

In the evening all bees were inside the box with a few sitting outside on it. I transported them to on of my yards and hived them.

Three nice colonies in less than a week!

Treatment free feral bees

Posted on March 23, 2015 by Erik

Up till now anyway, this colony of bees (and their ancestors forming this colony’s ancestor colonies) that has lived in a wall since several colony generations, has never been treated with any kind of chemicals ever, against Varroa mites or anything else.

June 29 last year I caught a swarm that came from this wall in a non-heated old house. (http://www.elgon.es/diary/?p=515) Towards the outside of the wall from the bees they had no insulation whatsoever. Just a thin board of wood. At the inside though a thick log wall.

For a couple of years there’s been an Elgon apiary 3 km away (2 miles). But the bee colony has been longer than that in the wall. Further back in time the closest apiary was 6 km (4 miles) away. At that time the Varroa mite had not arrived to these bees. For many years this colony has swarmed every year.

The swarm I caught was not big, but it had an egglaying queen and built up strength well enough to winter safely. To help it make a lot of brood I provided it with a shallow super above an excluder. I shouldn’t have done that I think as it was too easy for me to just take away this honey super when it was time to prepare the colony for winter. That is stressful time.

Now the bees hadn’t much honey left so I gave them 20 kg (44 pounds) of sugar in sucrose solution. If I hadn’t taken the small amount of honey it would have had about 10 kg (22 pounds) of honey for winter storage. Seeing how the colony behaved I think it would have made it well through winter with that amount. My first colony ever in 1974 had about that amount its first winter.

I saw no wingless bees during the season last year, so they got no Thymol against mites. I didn’t then have any quick way to measure the mite population (but here is at least one: http://www.elgon.es/diary/?p=354) And as I mentioned it was stressful times for me.

The queen stopped laying entirely in late summer. In November I saw through the plastic sheet used as kind of inner cover that the bees was sitting tight together like vacuum-packed peanuts.

About 10 March this year when the bees had their main cleansing flight after winter the cluster had spread out and filled more room than in November. It was very few dead bees on the bottom board. And not one defecate spot at the entrance.

These bees seems at least to be more winter hardy and be more Varroa resistant than common beekeepers’ bees, which have not been selected for Varroa resistance.

A possible scenario

A swarm of Elgon bees flying from the Elgon beekeeper 6 km away finds the cavity in the wall. Varroa mites havn’t arrived yet to the area. No beekeeper robs the honey or exchanges it for sugar. The cavity is not bigger than maximum two big boxes a beekeeper uses. The amount of brood can’t be as big as in a beekeepers hive. And the restricted area makes the volume finally too small for the bees (no beekeeper puts on boxes) and they swarm, every year mostly. Insulation is almost none. No beekeeper renews the wax and the bees build what they want when it comes to for example cell sizes. The Elgon beekeeper used small cell size to begin with. Here the cell sizes may become still smaller due to cocoon residues.

The bees adapt to the new environment now when they are on their own, like they were before there were any beekeepers around. In this adaption process the epigenetic process is most important, at least at first. The different environment created by a different “hive”, different food (more natural) and different cell sizes (also still smaller) gives a different chemical environment of many aspects. For example the different cell sizes give somewhat different food for the larvae, amount and probably composition also. This results in switching off some genes and turning on others in the DNA. Disturbing chemicals like pesticides and treatments in the hive can hinder this epigenetic process. But not for this swarm. It lived in a non-farming area and no beekeeper put chemicals in their hive.

There were no neighbor bees. Thus no bad influences from non-resistant bees drifting into their hive and no reinvasion of mites.

When the Varroa mites arrived the drones that became “fathers” were those that the mites didn’t parasitize. Maybe they avoided those drone larvae. And also those drones that were parasitized but were not as affected as others, became “fathers”. Thus also an adaption for resistance took place with a change of the DNA. Natural selection thus took place.

As the colony swarms every year there is a break in the brood production. This hinders the reproduction of mites. Also there is both an epigenetic and a genetic adaption with the new generation.

The smaller cells give less attractive food for the mites. They get less fertile on larvae in smaller cells. http://www.elgon.es/diary/?p=596

Drone cells get smaller in colonies on smaller worker brood cells. With smaller worker brood cells you get worker bees that get more hygienic. http://medycynawet.edu.pl/index.php/component/content/article/336-summary-201412/5234-summary-med-weter-70-12-774-776-2014 or http://alturl.com/a8scb Small cell beekeepers, including me, reports a widespread occurrence of uncapping and chewing out of capped brood in both worker and drone brood parasitized by mites. http://www.elgon.es/diary/?p=544 But VSH is said sometimes to not occur on drone brood. But those bees are kept on large cells. At least it doesn’t occur as much in drone brood. But it is observed quite a lot sometimes in small cell colonies as mites are observed to be much more common there in drone brood than in worker brood. http://resistantbees.com/blog/?page_id=2471

What happen with feral bees in a beekeeper’s hive?

If a swarm from feral bees end up in a beekeeper’s hive with large cell size, the environment changes and a “reverted” epigenetic process takes place. If there are more bee colonies in the apiary or close by all bees will be drifting (as is common) in all colonies and be mixed more or less. If these other bees have no or very little resistance against Varroa they will have a negative impact on the more resistant feral bees. These were enough resistant in the wall. Are they enough resistant now in this beekeeper’s hive? Maybe not.

If the feral swarm ends up in a beekeeper’s hive with small cell size, and there are neighboring bees that have substantial resistance against the mite, it may be that this swarm will do very well fighting the mites. Especially if there are no or very few bees around that can’t make life miserable for Varroa mites.

What will happen with my feral bees? Will they continue to be treatment free?

Meeting the sun

Posted on March 17, 2015 by Erik

The second Sunday in March the temperature, wind and sun, together with filled intestines of the bees that had produced the heat for the winter cluster took these bees out to meet the sun. The main cleansing flight took place. What a relief!

Most often in Sweden you reach well into March before the main cleansing flight takes place. Now the colony has been brooding for some time, and this accelerates now. If the colonies started to make brood too early, for example due to a warm spell in January, or if you have Italians that have a hard times taking a break in brooding, this last winter was hard at them as winter never really came until February for two weeks. Those colonies have produced many Varroa and filled their intestines early because they have used a lot of food. The immune system is thus weak. Virus, Nosema and chemical residues contribute to the risk of defecating inside the hive, if there are bees left there. Many may already have left just flying out away from the hive (due to virus) leaving it sometimes empty of bees.

This winter should have been easy for the bees due to its mildness. But for many beekeepers that have trusted oxalic acid in late autumn and drone brood cutting in beginning of season (and just that) to fight the mite, this winter has been a bad experience. For a couple of years this concept may have worked okey. And the beekeepers, perhaps beginners, have thought they are safe.

But last year the longer brood season together with no or little checking of the mite population in July/August (mite population should not be too high then when the winter bees are produced), the mite population was too high when oxalic acid treatment came in October. The weakened bees then were still more weakened by the acid and overwintering became still harder. And it became even harder as the bees still had brood when the oxalic were used. Most mites were in that brood (that of course had well developed virus population by now) and escaped the oxalic. So it’s easy to explain the winter losses of such hives.

Now a beekeeper named Bengt Haglund just north of Stockholm have used thymol gel (Apiguard) with 25 grams of thymol in the gel in one small tray in spring. Upside down directly on the top bars, just above the brood. Next treatment was directly after late summer harvest. Another tray of Apiguard with the opening upward this time, between the two brood boxes. Winterlosses for five years in average 1 % for Bengt.

My goal is treatment free. I’m close. To get there I have chosen to use small cells, breed for resistance and use good quality natural food as much as possible. On my way to this goal I made the conclusion that I was about to loose almost all my colonies when the Varroa arrived. Therefore I treated, reluctantly, and lost “only” 50 %. The only season I have lost that much, in 2008-09.

So I used Thymol. But I don’t use anything until I see wingless bees. The virus causing it is the most common associated with Varroa mites. And I use as little as possible. I’ve found a piece of dishcloth with 4 grams of soaked in thymol is enough to start with, on top of the top bars close to the brood. Every ten days another piece as long as I see crippled wings. Strong hives might get two pieces at a time. Most hives get it in spring and later just after harvest. If there is some smelling left in the boxes when I harvest, it stays in the wax actually, and in the woodenware. The honey does not get any extra flavor (if it should it’s not unhealthy at all). Thymol residues are finally ventilated away.

Yes, Thymol kills microbes. But sometimes it’s better to have dead microbes and live bees, than dead bees and with them dead microbes. And Thymol is much less dangerous for me than oxalic acid – when making the oxalic solution, when handling it, when handling eventual fumigation and when handling equipment with crystals when cleaning up dead colonies.

But again, the goal is treatment free. And I’m almost there. Last year many colonies didn’t need any Thymol. Many got only 4 grams. Another lot 8 grams, and 12, and 16. A few more, and up to 40 grams at the most. Those that got 16 and more will have their queens shifted this year.

Winter losses for me up till now is about 5 %. Still some more % will not make it until May I’m sure.

Most colonies look very fine. And it seems I have several fine breeders to use. I’m happy the investment in breeding for resistance pays.