Are rhododendrons toxic to bees?

Rhododendron ponticum

By Rasbak – Own work, CC BY-SA 3.0,

Short answer: it depends upon the rhododendrons and also on the bees.

There was an interesting article recently in February’s BBKA News, ‘Bitter Sweet Nectar: Why Some Flowers Poison Bees’ by Stephanie Pain. It was all about sources of toxic nectar, including the common rhododendron, Rhododendron ponticum. This flower is known as a source of ‘mad honey’, used by European armies through the ages as a weapon of war. The honey would be left in the path of invading legions; the soldiers would eat the sweet treat and end up vomiting and dizzy from grayanotoxin, a toxin contained in rhododendron honey. The effects rarely prove fatal to humans but probably would have halted or slowed down armies for a while.

Rhododendron ponticum

Rhododendron ponticum By First Light at English Wikipedia, CC BY-SA 3.0,

R.ponticum was introduced to Ireland in the 18th century and has invaded large areas of the countryside, where it is regarded as a pest. Yet research led by Jane Stout, Professor in Botany and Dr Erin Jo Tiedeken, Research Fellow at Trinity College Dublin, has found that its flowers are visited almost exclusively by bumblebees, with occasional visits from solitary bees, flies, ants and wasps. They found that the nectar’s grayanotoxins cause palpitations, paralysis and death within hours for honey bees. In contrast the nectar has no apparent effect on worker buff-tailed bumble bees. Professor Stout suspects that the subspecies of honey bee that makes mad honey in the rhododendron’s native range has probably evolved to resist the toxins in a similar way to the bumblebees.

I tweeted about Professor Stout’s research and had some interesting responses. One Welsh beekeeper, @Greengrumbler,  disagreed with the research findings, arguing that they often see honey bees on R.ponticum in Wales:

However, Liverpool beekeeper Andrew Hubbard, @dunbarrover, thought he might have experienced it:

Meanwhile Emma shared a useful link from the Poison Garden website which suggested that most of us will be unable to tell what is R.ponticum and what is a hybrid – and therefore potentially less toxic – plant.

“Rhododendron is thought to appear in around 1,000 species and those species produce innumerable hybrids. This means there are very few people expert enough to identify exactly what Rhododendron a particular plant is.

In terms of appearance and flowering, that doesn’t matter too much but it has been found that the concentration of the main toxin is species/hybrid dependent so plants that appear to the layman to be identical may produce different degrees of poisoning.” – John Robertson,

Either way, it sounds like rhododendron is unlikely to cause British beekeepers many problems. If we do have R.ponticum near us, our bees will probably avoid it. If we only have hybrid rhododendron species nearby, the hybrids may well be less toxic. It may only be a problem for beekeepers surrounded by R.ponticum, which could smother out other plants and reduce the amount of forage available for honey bees.

See more:

  • Grayanotoxin Poisoning: ‘Mad Honey Disease’ and Beyond
    A scientific paper on mad honey. Contains a fascinating description from the Greek warrior-writer Xenophon in 401 BC on the effects of the honey on an army –  “those who had eaten a great deal seemed like crazy, or even, in some cases, dying men”.
  • A rare case of “honey intoxication” in Seattle
    Rusty at Honey Bee Suite reports on the rare case of a man who may have been poisoned by honey purchased at a local farmer’s market. Rusty’s observations have led her to believe “that rhododendron is not a preferred forage for honey bees and they probably collect it only in rare circumstances when other more favorable blooms are not available.”
  • “Mad Honey” sex is a bad idea
    That got your attention!
  • Hallucinogen Honey Hunters documentary
    A tribe in Nepal hunt wild rhododendron honey with natural psychoactive properties. One falls unconscious after overdosing on the honey.
  • The strange history of ‘Mad Honey’
    Emma Bryce writes about Turkey’s hallucinogenic rhododendron honey (deli bal), produced on remote mountainsides smothered with vast fields of cream and magenta rhododendron flowers.
Posted in Foraging, Honey | Tagged | 22 Comments

Notes from a talk by Norman Carreck – colony losses, native bees, pollen diversity and the small hive beetle

Yesterday I went to a talk by Norman Carreck, which was organised by the London Beekeepers Association (LBKA). One of the great things about being a beekeeper in London is being able to hear expert speakers like Norman. He is currently Science Director of the International Bee Research Association (IBRA), based at the Laboratory of Apiculture and Social Insects at the University of Sussex.  He has kept bees since he was 15, obtained the National Diploma in Beekeeping in 1996, is a member of the Technical and Environmental Committee of the British Beekeepers Association, a member of the Examinations Board for the National Diploma in Beekeeping, a member of the “Bee Health Advisory Forum” for the Defra “Healthy Bees Plan”, the UK member of the Executive Committee of the international honey bee research network “COLOSS” and Senior Editor of the Journal of Apicultural Research.

Norman Carreck

Norman Carreck

Despite all Norman’s achievements he came across as an unassuming and modest speaker, who took plenty of time to answer everyone’s questions afterwards. His talk was about research projects carried out by COLOSS  (which stands for Prevention of honey bee COlony LOSSes), on the themes of colony loss monitoring, local bee vs imported bee survival, pollen diversity and the small hive beetle.

How COLOSS works

It’s an international, non-profit association set up following the publicity surrounding colony collapse disorder in 2006, when many beekeepers first reported losing large numbers of colonies. There are 722 members in 89 countries worldwide, with membership open to scientific professionals interested in the well-being of bees. COLOSS holds regular meetings, but has very little money, so the individual members fund themselves to attend. Norman told us that in a way this lack of money is an advantage – as it means members aren’t competing with each other for central funding from COLOSS, which encourages mutual cooperation.

Colony loss monitoring

To try to gather data to establish whether honey bee losses are a genuine global phenomenon, COLOSS members came up with a standardised questionnaire for beekeepers. A lot of thought went into the questions in order to take account of the differing lengths of international beekeeping seasons and practices. Norman mentioned that although both the British Beekeeping Association and National Bee Unit do annual surveys which ask beekeepers some of the same questions, COLOSS has had difficulty getting the results of these surveys – which has been a frustrating situation.

A female varroa mite - © Crown copyright 2010 "Courtesy The Food and Environment Research Agency (Fera), Crown Copyright"

A female varroa mite – © Crown copyright 2010 “Courtesy The Food and Environment Research Agency (Fera), Crown Copyright”

The surveys carried out so far indicate that colony losses do in general seem to be higher than 30 years ago – but there are no obvious patterns to this – with losses varying between countries from year to year. Climate itself doesn’t appear to be a big factor, as beekeepers have developed their own systems to cope with their particular climates. Weather is important but doesn’t explain all the losses. Varroa is very important, with higher losses occurring when beekeepers don’t treat against mites. Areas of intensive agriculture also tend to have high losses – this may be due to a lack of forage diversity for the bees, particularly at times of the year when the main farming crops have finished flowering. The most recent results available are for losses over the 2014/15 winter.

Are people keeping bees suitable for where they live?

COLOSS scientists wanted to compare how successfully individual strains of the European honey bee (Apis mellifera) cope in a range of environments. To do this they set up an experiment comparing 16 genetically different strains at 21 locations, across 11 European countries. At each location, a local strain of bee was compared with two other strains. For three years, six colonies of each strain (so 18 in total) were monitored for honey production, disease, colony size etc at each site. They were not treated for varroa, which meant several died early on.

The results of this study were published in a number of papers, including ‘The genetic origin of honey bee colonies used in the COLOSS Genotype-Environment Interactions Experiment: a comparison of methods‘ (Francis, 2014) and Honey bee genotypes and the environment‘. Across all the locations, there was no one strain that consistently had better survival rates. BUT there was a statistically significant difference between the survival rates of local and non-local bees – local bees survived longer. One reason for this could be that local bees have adapted to cope with local strains of pathogens. Whatever the reason, the study indicated that local bees do better. Food for thought for beekeepers who regularly import queens from the other side of the world or buy in packages from hundreds of miles away.

Andrew Abrahams

Andrew Abrahams

There has been some doubt over whether it’s possible to keep your bees pure, considering the queen honey bee will mate with as many local drones as can catch her. Andrew Abrahams is the only beekeeper on the Isle of Colonsay in Scotland and asked one of the Scottish heritage bodies for assistance in getting legal protection for his dark European honey bees. He was initially refused it and told bees shouldn’t be on the island at all, but eventually he won protection in a new Scottish government order which makes it an offence to keep any honey bees on the islands except the dark European honey bee, Apis mellifera mellifera. For more on this, see:

I notice Andrew runs beekeeping courses on the island. My husband Drew spent many summer holidays as a child on Scottish beaches, including stays on Colonsay… hmm maybe he can be persuaded that we really need to show our new baby the beauty of the Scottish islands and their wildlife!

Anyway, a study on the ‘Genetic integrity of the dark European honey bee‘ (Pinto et al 2014) confirmed that Andrew Abraham’s bees are pretty pure Apis mellifera mellifera; more surprisingly, even openly mated bees from Sussex University campus had a lot of Apis mellifera mellifera in them. Local strains survive well. COLOSS are currently putting together a book on sustainable bee breeding, to advise beekeepers on making the most of the bees we have rather than importing them.

Pollen diversity

CSI Pollen logo

In 2014 COLOSS began a “C.S.I. Pollen” study asking beekeepers to help collect data on the diversity of pollen collected by their bees. To take part, each beekeeper needed three colonies, each fitted with a trap to collect pollen on ten dates over a year. After each collection, the beekeepers were asked to separate out 20g of the pollen on a white tray and count the number of different pollen colours they could see.  Norman commented that this is not a perfect test as one plant may produce pollen grains which look like different colours (for example maize pollen is darker when wet), but at least all the beekeepers have done the sampling in the same way, so the data is standardised.

During 2014, 465 beekeepers in 24 countries took part. The initial data gathered from English and Welsh beekeepers during 2014 indicated that pollen diversity declined as the beekeeping season went on. The study was expanded during 2015, with many more beekeepers from 27 different countries taking part. The original data is still being analysed and a draft paper has been written.

The surveying will continue in some countries during 2016, including England, Wales, Scotland, Ireland and France. More volunteers are needed, so contact Norman if you’re interested.

Small hive beetle (Aethina tumida)

Like the Asian hornets, most UK beekeepers will be aware of these pests and the threat that they may reach us sooner rather than later. Norman described the beetles as “fairly repulsive things”, which make varroa mites look attractive in comparison.

Small hive beetle, Crown copyright

Small hive beetle, “Courtesy The Food and Environment Research Agency (Fera), Crown Copyright”

The beetle larvae hatch out in the hive and feed on comb containing pollen or honey, damaging the comb by tunnelling through it and defecating, which makes the honey ferment and run out of the combs. Heavy infestations of the larvae turn the combs into a sloppy mess that U.S. beekeepers call a “slime out”.

Once ready to pupate, the larvae leave the hive and burrow into soil, before emerging as adult beetles 3-4 weeks later. The adult beetles seek out bee colonies to mate in, then the females lay masses of eggs within cracks and crevices amongst the hive to start the cycle again.

One of the challenges in keeping the beetles at bay is that we don’t know how far the larvae travel to pupate. Norman could only say that they can wander “quite a long distance”. Additionally, the adult beetles fly – again we don’t know how far. More research is needed to confirm this.

1996, Florida
The beetles are native to sub-Saharan Africa, where they are a minor pest but not a serious problem. As usual the activities of humans moved them around the world, with the result that in 1996 beekeepers in Florida suddenly found their colonies full of the beetles. They wiped out many colonies and rapidly spread to several different states, where they remain today.

2004, Portugal
Beetles turned up in Portuguese colonies containing queens imported from the US (another reason not to import foreign queens). Some were discovered in the cages the queens had been released from. The Portuguese authorities moved quickly to burn all infested colonies and fortunately the beetles were eliminated.

2014, Southwest Italy
Beetles were discovered in Italy in 2014, causing panic. The Italian authorities started destroying lots of hives by burning, then sprayed insecticides to kill any beetles which might have been pupating underground. They found 61 infected sites and destroyed over 3,500 colonies. However, due to the sheer number of beekeepers in the area, not all apiaries were inspected.

Around 20,000 packages of bees were exported from Italy in 2014. In the UK our National Bee Unit inspectors tracked down any packages imported from Italy and inspected them – all were found to be clear of beetles. Other countries were not so thorough; for example the Polish government said it did not have the financial resources to inspect imported packages.

To try to help, COLOSS ran articles on the beetle in IBRA’s Bee World journal and organised a task force. A book called The small hive beetle in Europe which Norman has edited will be available soon. At a conference organised to debate the options available, it was clear that the patience of Italian beekeepers for the government’s policy of destroying hives was wearing thin. Compensation from the government took a year to arrive and then only compensated the beekeepers for colonies destroyed, not for loss of income from queen exporting or honey sales. Rumours began that beekeepers were not reporting beetles to authorities and quietly destroying infected colonies instead (or perhaps not destroying them).

2016, Italy
Some more cases were found in December 2015… with virtually all sightings including adult beetles, which indicates that they’re breeding. Norman suspects the chances of eradicating the beetles in Italy are slim.

Coping with the small hive beetle

African bees have developed strategies to deal with the beetles, for instance entombing them in propolis traps. European honey bees do this too, to a certain extent. So we don’t entirely know why they are such a problem for European honey bees. One theory is that African plants provide more propolis, so African bees just have more of it available to contain the beetles.

After the initial problems in the US, many beekeepers there have now learnt to live with the beetles. Sloppy beekeeping seems to be the main issue which allows the beetles to get out of hand and reproduce in vast numbers. Good apiary hygiene, such as processing honey immediately, not storing old comb/keeping honey combs in fridges or freezers, helps keep numbers low. Smaller hives also assist the bees in keeping beetles contained, as does not inspecting too often (beetles are released as beekeepers move combs apart and break propolis seals open).

Norman is sure the beetles will reach the UK eventually. They are attracted to the smell of rotting fruit and have even reproduced in rotting bananas under laboratory conditions. This means they could potentially move around the world in fruit consignments or pupating in pot plants, not just through bee imports.

They like dry, sandy soil, so damp, waterlogged clay soil like we have in some areas would deter them. They could potentially do well in the New Forest, which has light, sandy soil. Unfortunately the early detection methods we have are not good. Traps work well if you have lots of beetles; but if you only have one beetle in your hive there are plenty of other nooks or crannies it could end up in. Our WBC hives would be perfect for beetles to hide in!

See also…

The Laboratory of Apiculture and Social Insects at the University of Sussex, which Norman is based at, is running some workshops this summer/autumn. These are only £10 to attend and must be booked in advance as they are popular. You can choose from:

And a couple of videos of Norman lecturing:

This post is dedicated to my cat Bob, in honour of his steely determination to stop me typing it. 

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Middlesex Federation Day Part 2: Pam Hunter, How nutrition affects colony health

My second post on the Federation of Middlesex Beekeepers’ Associations annual ‘Federation Day‘. Below are my notes from the second speaker, Pam Hunter.

Pam is a Master Beekeeper who has been keeping bees for over 25 years. She is now Chairman of the BBKA Examinations Board, sets and marks module exams and is an assessor for the Basic, the General Husbandry and the Advanced Husbandry exams. She has a particular interest in the interaction of plants, bees and the environment as well as the more biological/scientific aspects of bees and historical aspects of beekeeping.

Pam Hunter, How nutrition affects colony health

Pam explained in detail the different substances contained in nectar and pollen. She recommended an Australian government publication with the cute name ‘Fat bees, skinny bees‘, the pdf of which is free to download. This goes into the chemical composition of nectar and pollen and explains the nutritional requirements of honey bees.

Pam Hunter

Pam Hunter

Pollen is very precious, providing bees with protein, fats, minerals, organic acids and vitamins.

It is needed in large quantities when raising brood – partly because some is directly fed to the brood, but mainly because young nurse bees need to eat lots of pollen to produce ‘brood food’.

[After Pam’s talk I investigated exactly what’s contained in brood food – this special food for the growing larvae contains a mix of white food (from workers’ mandibular glands), clear food (from the hypopharyngeal glands in workers’ foreheads) and yellow food (from pollen). For workers the mix is on average white:clear:yellow in ratio 2:9:3 (ref. Mid Bucks Association Module 5 study notes, p.29).]


Nurse bees feed on pollen so that their hypo pharyngeal glands develop. The young nurse bees have puffed up, fat hypopharyngeal glands, full of enzymes busy turning pollen into brood food. In contrast, the glands of older foragers no longer producing brood food are all shrivelled up.

Most of us beekeepers know that the queen is not really in charge of the colony, but Pam went one step further by telling us that the older foragers are dominated by the young nurse bees. In her view, it is the nurse bees who are really in charge – they are at home keeping an eye on brood, pollen, honey, water and propolis levels, so know what the colony needs.

Not all pollen is equal
Pollen can have widely varying crude protein levels of between 2.3 – 67%, with at least 20-30% protein being desirable. Pam said it is highly likely that some pollens are lacking ‘essential amino acids’ like Isoleucine. Certain amino acids are ‘essential’ because they can’t be made by the bees themselves but have to be consumed through food.

In 2014 I went to a Middlesex Federation Day talk by Dr David Aston, who at the time was President of the British Beekeepers Association (BBKA). He showed us the below chart of the percentage of crude protein in various pollens, which I jotted down hurriedly (so any mistakes are mine). As you can see, he has blueberry, weeping willow and sunflower listed as particularly poor for bees.

% of crude protein in pollen (source David Aston)
Inadequate pollens
  • Pollens which are inadequate for honeybee nutrition: blueberry, weeping willows, sunflower
  • Coniferous trees such as pine, spruce, fir and cedars are also especially poor.
Poor pollens
  • Sunflower: 13%
  • Maize: 15%
  • Weeping willow: 15%
  • Lavender: 20%
Average pollens
  • Pussy willow: 22%
  • Oil seed rape: 24%
  • Vetch: 24%
  • Dandelions, sweetcorn, elm, ash have average pollens too
Above average/excellent pollens
  • Almond: 25%
  • White clover: 26%
  • Pear: 26%
  • Vipers Bugloss: 35%

Bee with orange pollen

Fresh is best
Research suggests that bees need a great variety of pollen and that it is not wise to stockpile pollen frames because its nutritional value deceases rapidly after collection – by about 75% after a year. This makes late pollen sources like Michaelmas daisies, sedums and ivy and early sources like hazel important, so that the bees can get fresh pollen with greater nutritional value.


Fatty goodness
The fats provided by pollen also play an important part in metabolism. Some fats are metabolised to fatty acids and glycerol, providing energy for muscle contractions in flight or when clustering. Fat is also needed for proper larval development. Experiments have found that honey bee larvae deprived of fat are more likely to die early on. Both humans and bees do need some cholesterol! The audience looked cheerful when Pam told us this.

Pollen is also needed so that the bees can store food reserves in their bodies, in the form of “magic stuff” called vitellogenin. It’s a ‘glycolipoprotein’ – a complex molecule containing protein, fat and sugar. It’s very important for building fat stores in winter bees. Winter bees are stuffed full of fatty deposits, including these vitellogenins. Pam mentioned that Randy Oliver has a lot of information on vitellogenin on his website and indeed he does:

  • Fat Bees – part 1 – Randy talks about brood food, the benefits of vitellogenin for larvae and nurse bees, how it helps bees overwinter and how vitellogenin levels influence foraging and swarming behaviour.

Nectar mainly provides the bees with carbohydrates, in the form of sugar. Nectars contain different combinations of sucrose, glucose and fructose. Foragers add the enzyme sucrase (contained in their saliva) to the nectar they collect, which breaks down sucrose to produce glucose and fructose.

Honey bee on borage. Courtesy The Food and Environment Research Agency (Fera), Crown Copyright.

Honey bee on borage. Courtesy The Food and Environment Research Agency (Fera), Crown Copyright.

A honey which contains a high amount of sucrose can be a sign that it’s been produced by feeding the bees sugar syrup – but not always. A Yorkshire beekeeper was once accused of feeding his bees sugar before it was discovered that borage is an unusually high sucrose nectar. The England Honey Regulations 2015 make allowances for this, requiring that honey has a sucrose content of not more than 5g/100g, with a few exceptions for certain honeys, including borage, which can have up to 15g/100g (see page 10 of the regs).

In this August 2010 Statford-upon-Avon & District Beekeepers’ Association newsletter, Peter Edwards writes “This high sucrose level combined with low glucose results in a honey that will not set – so this makes it popular with the packers as it can be used to produce clear honey with an almost indefinite shelf life. The next problem with borage honey is its total lack of flavour unless mixed with something else.  Pure borage honey is completely white and looks, and tastes, like sugar syrup with maybe just a hint of cucumber skin – yuck!”

Factors affecting nectar flow

Pam talked about some of the difficulties bees face in collecting nectar. There are all sorts of factors which affect how much nectar flowers provide:

  • Humidity
  • The moisture & PH of soil
  • Sunshine – it’s said that dandelions only produce nectar if they’ve been in sunshine for two hours. Many plants – oil seed rape for example – don’t produce nectar in cold temperatures. Pollen availability is much less affected by the weather.
  • Time of day – bees go to apple blossom for pollen in the morning and nectar in the afternoon.
  • Age & vigour of the plant – young blackberry plants produce more nectar.

What makes a good colony?

Pam concluded that a healthy colony needs a steady supply of nutrients. She gave us a couple of quotes she likes:

“The very best queens will not be produced except under the best conditions!” (A.L.Gregg)

“If queens were not well fed in the early larval stage, they will be superseded early” (A.I.Root, The ABC of Bee Culture)

Without protein, a colony can survive on pure sugars for some time, but the bees will not be able to develop their hypopharyngeal glands and rear brood. If pollen being collected has a low protein content, nurse bees can feed fewer larvae. During protein shortages brood may be eaten by the adult bees.

There is also evidence that a lack of pollen can reduce the immunocompetence of bees. In controlled trials by DeGrandi-Hoffman et al (2010), a reduction in virus levels was seen in bees fed good pollen supplies.

As discussed earlier on by Pam, not all pollen is equal – she quoted a study by Schmidt et al (1995), which involved feeding colonies either rape, sunflower or sesame pollens. The bees fed sesame or sunflower pollen lived shorter lives (31 days on average for the bees fed sunflower pollen, compared to 51 days for the bees fed rape pollen). The authors suggested that honey bees used to pollinate monocrops of sunflower or sesame flowers should be provided alternate floral or nutritional supplements to maintain colony health. This will have particular relevance to beekeepers in France, which has vast sunflower fields.

See also…

My hive partner Emma’s write-up of Pam’s talk: Federation of Middlesex Beekeepers Day 2016.

Pam mentioned that Professor Geraldine Wright‘s lab in Newcastle is doing the first new work on honey bee nutrition for many years. There is still lots we don’t know.

And a lot of Pam’s talk overlapped with the content of the BBKA Module 2 (Honey bee Products and Forage) and Module 5 (Honey bee Biology) exams, which the Mid Bucks Association have produced excellent study notes for: Module 2 study notes and Module 5 study notes.

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Middlesex Federation Day Part 1: Professor Field, Why do we use insecticides?

Yesterday I went to the Federation of Middlesex Beekeepers’ Associations annual ‘Federation Day‘. Each year the Middlesex associations (Ealing, Enfield, Harrow, North London, Pinner & Ruislip) take it in turn to host a day of beekeeping talks; this year the day was organised by the Enfield association, in a remote area of north London which took me around 2 hrs 45 mins to reach from my part of west London!

The travelling was worth it as I learnt lots from three expert speakers.  Below are my notes from the excellently-named first speaker, Professor Field. She works at Rothamsted agricultural research station, focusing on understanding insecticide mode of action and resistance at the biochemical/molecular level and then using this to develop better pest control strategies. Recently she has played a role in developing Rothamsted’s policy on the effect of neonicotinoids (neonics) on bees and a lot of her talk was spent giving us an update on the neonics situation.

Why do we use insecticides and what are the threats for bees?
Professor Linda M. Field. Head of Department, Rothamsted Research

Professor Linda Field

Professor Linda Field

Advantages of neonics: 

  • Very selective to insects, not toxic to mammals
  • Systemic – travels through plant to leaves and flowers if used as a seed dressing (this has turned out to be less of an advantage than initially thought, as it means neonics end up in the nectar and pollen). Avoids the need for costly sprays which are potentially more damaging to local wildlife.
  • Pests take a long time to develop resistance to neonics
  • If used properly, little evidence that they directly kill bees

Problems with neonics

  • The question is not “Are they killing bees?” but “Are they having a sub-lethal effect which causes problems for bees?” – for instance, stopping foraging bees finding their way home. There is evidence that this is the case, but we don’t understand why this might be.
  • To gather research in the field, large-scale experiments are required to find out if neonics are a problem. These studies are not being funded by governments.

Lots of other factors beside pesticides are causing bees problems – varroa, viruses, weather, loss of forage – these are important but less easy to control and stop.

Where are we with neonics now?

In 2013, Regulation No 485/2013, the European Commission restricted the use of three neonicotinoid pesticides, clothianidin, thiamethoxam and imidacloprid, preventing the use of seeds treated with them in EU member states.

No-one has monitored the overall effect of the ban! The EU is not providing money for research into neonics. We have some scientific papers from independent organisations, but the research has been done in varying ways using different methods, making it hard to compare. A decision is unlikely to be made on what to do next until spring 2017.

The most recent EU report was in April 2015, by the European Academies Science Advisory Council (EASAC): Ecosystem services, agriculture and neonicotinoids. Professor Field recommended the conclusions at the end of the report (p.29) to us as the “easy bit to read”. She went through some of the report’s conclusions and gave us her comments on them:

“There is an increasing body of evidence that the widespread prophylactic use of neonicotinoids has severe negative effects on non-target organisms that provide ecosystem services including pollination and natural pest control.” (Conclusion 5)

Professor Field agreed with this but added that equally there are also papers which have found the opposite.

“Current practice of prophylactic usage of neonicotinoids is inconsistent with the basic principles of integrated pest management as expressed in the EU’s Sustainable Pesticides Directive.” (Conclusion 7)

Professor Field commented that people often take the word ‘prophylactic’ as implying unnecessary usage, whereas most farmers can reliably predict that certain pests will turn up each year. As mentioned above, one of the advantages of neonics is that pests take a long time to develop resistance to them. When the neonics ban was put in place here, weevils began destroying oil seed rape crops, resulting in some farmers spraying with pyrethroids 4-5 times in an attempt to kill them – but the weevils had developed resistance to pyrethroids. By the time farmers and agricultural advisers realised this, the sprays had also killed beneficial insects that might have helped control the weevils.

“Widespread use of neonicotinoids (as well as other pesticides) constrains the potential for restoring biodiversity in farmland under the EU’s Agri- environment Regulation.” (Conclusion 8)

Professor Field said there is a lot of debate going on about how to combine habitat diversity and farming. Should we try to share farming land with native species and make it biodiverse? A nice idea but not optimal for either farmers or wildlife. Or farm some areas of land intensively while leaving other areas aside for biodiversity? There is evidence that this approach may help rare species more.

Current UK situation

The UK government temporarily lifted the ban and allowed about 5% of farmers to sow neonic treated oil-seed rape in autumn 2015. This applied to farmers in areas where there is high resistance to pyrethroids in cabbage stem flea beetles, a pest of oil-seed rape. There are a lot of oil-seed rape crops out there which survived the initial onslaught but are full of beetle larvae waiting to attack. We may see farmers start to plant more field beans and pulses.

The COLOSS 2014-15 winter losses data showed low honey bee colony losses in the UK compared to many other European countries. The overall proportion of colonies lost (averaged out across all 31 countries surveyed) was 9%, the lowest since the COLOSS international working group started collecting data in 2007. But we really need the 2015-16 winter data to try and see if the ban has had an effect. There will be all sorts of factors affecting colony losses in any case, including the weather and varroa. We still have limited national data on numbers of solitary and bumble bees, which the EASAC report noted are more vulnerable to the risks from neonicotinoid use.

Bramble flowers against the sky

Insecticides and pollinators – are they incompatible?

Professor Field concluded that we can have both, through:

  • Biological controls – for example plants that naturally repel insects or plants that are naturally resistant to pests. GM has the potential to engineer plants to be naturally resistant.
  • Cultural controls – rotating crops more, mechanical sowing.
  • Using pesticides as a last resort when other methods don’t work!

I was left feeling ambivalent about neonics. In some ways they are better than the pesticides that came before – none of us want to go back to DDT. At the same time, I would rather have a countryside which is more welcoming to pollinators. I support the EU ban because at least it’s trying something – at least it’s an attempt to protect pollinators, see what the effects of neonics are and if banning them can help.

See also Emma’s write-up of the day on her Miss Apis Mellifera blog, I missed the beginning of Professor Field’s talk but she was there for it all: Federation of Middlesex Beekeepers Day 2016.

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What’s flowering now: early February

Everything is early this year. So we have snowdrops at the apiary:


Crocuses at Northfields allotments:

Yellow crocuses

Purple crocuses

Blossom on the trees:


It were a mild day today, so the allotment bees were out and about.

Allotment hive

The plots were quiet except for birds hopping over the bare earth. The main crops in view were the strange shapes of brussel sprouts.

Brussel sprouts

All is quiet with the bees at the moment, but before we know it spring will be underway and the first swarms will be here.

Thanks to Margaret Anne Adams, who posted helpful December 2015 advice from the Regional Bee Inspectors on the BBKA Facebook page: INSPECTORS_ ADVICE.docx – apparently there have been outbreaks of European Foulbrood (EFB) in the Shropshire/Welsh borders. Part of the advice given to prevent these outbreaks is to change brood combs regularly and avoid re-using combs from colonies which have died out. Now is a good time to prepare new frames ready for spring Bailey or shook-swarm comb changes.

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Winter at last?

Last weekend brought a surprise – snowy rooftops. The white stuff melted fast, but the chilly air remained. Down at the apiary the ground was hard and all was quiet, with no bees flying.

Snowy roofs

When the bees are tucked up, the varroa boards provide a clue to the size and position of the cluster. The white flakes are particles of wax dropped by the bees as they uncap honey stores to feed. The dark brown oval shapes are varroa mites killed by oxalic acid trickling.

Varroa monitoring board

Each board tells a different story – some of the clusters are small and tight, others cover several frames. We have taken the boards out now as it’s not a good idea to leave them in all the time. This way the bees have ventilation at the bottom and plenty of insulation at the top, thanks to Tom’s specially built insulated roofs plus insulation foil from Wickes which we pack over the crown boards.

Varroa monitoring board

I checked the hive entrances and discovered that Melissa’s mouseguard had somehow come undone and fallen down on one side, leaving the entrance open. I put it back in place with extra drawing pins; hopefully I wasn’t trapping a mouse inside!

Varroa monitoring board

At this time of year I wish I could spend my winter huddling inside like the bees.  I don’t enjoy my winter commute – leaving for work and coming home from work in the dark, waiting at chilly bus stops.

Frolicking frost

The solution? A nice cup of tea. This lovely ‘Bee puffer mug‘ by Lush Designs was one of my Christmas pressies.

Beekeeper mug

I can put my bee mug down on a bee coaster from Chickidee too, another lovely Christmas present. Finding bee-themed baby clothes is my next mission 🙂

Bee coasters

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New LASI oxalic acid research published

A comment by the lovely Amelia from on my last post led me to look at the University of Sussex’s Laboratory of Apiculture and Social Insects (LASI) website.

I was dismayed to see a new press release, ‘Scientists determine how to control parasite without harming bees‘, which advises beekeepers not to use the trickling or spraying oxalic acid method (which is what most beekeepers I know use). Instead sublimation (also known as vaporisation) is recommended.

“Professor Francis Ratnieks, head of LASI, says that beekeepers should cease using the other two methods (“trickling” and “spraying”, in which a solution of oxalic acid is used) as they are harmful to the bees and less effective at killing Varroa.”

Research accompanying the press release was due to be published today (Tuesday 5 January 2016) in the Journal of Apicultural Research, but unfortunately this journal is not publicly accessible to non-subscribers. I’ll try to see if I can access it through work as I would like to read the research study – it’s called ‘Towards integrated control of varroa: comparing application methods and doses of oxalic acid on the mortality of phoretic Varroa destructor mites and their honey bee hosts’ by Hasan Al Toufailia, Luciano Scandian and Francis Ratnieks.

The press release says the trickling and spraying methods “cause harm to bee colonies, resulting in reduced winter survival”. I wonder why harm is caused, how great the harm is, and whether it outweighs the harm caused by not treating for varroa at all. Emma and I have never had any colony losses following oxalic acid trickling and I cannot recall other beekeepers having experienced this either, but perhaps LASI have found colonies to be weakened by it afterwards.

Hopefully Beecraft and BBKA News will mention the study in their February issues.

EDIT 29/02/16: The research has now been published and I’m grateful to the Journal of Apicultural Research for generously making it freely available to the public: Towards integrated control of varroa

Treating with oxalic acid. Courtesy The Food and Environment Research Agency (Fera), Crown Copyright.

Treating with oxalic acid. Courtesy The Food and Environment Research Agency (Fera), Crown Copyright.

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