Friday 6 April 2012

What are Neonicotinoid Pesticides and How Are They Killing Bees?

So much has been written over the last few years about Neonicotinoid Pesticides and their devastating impact on the world's bee population, but it is only recently, since the publication of three new scientific reports, that the effect these pesticides are having upon bees is finally being talked about openly in the mainstream media.

Although neonicotinoids have already faced bans and/or restrictions in varying degrees in countries such as Italy, Germany France and Slovenia, the UK government have, so far, ignored the mountain of evidence, including this in depth report from the charity Buglife - published back in 2009 - which shows quite clearly that neonicotinoids are contributing to bee decline.

I will attempt to explain as clearly as I am able in this article what neonicotinoids are and why it is imperative, in my opinion, that they should be banned. This is an extremely complex issue so I have provided links throughout to give more in-depth information when/if required.

Before I begin I just want to say that pesticides are only one part of the problem and also that it's not just honeybees that are suffering. There are other reasons for the decline in bee numbers (and species) including: the exploitation and over farming of honeybees and bumblebees by some commercial beekeepers; pollution; climate change; and - of enormous significance - habitat degredation, fragmentation and loss caused by intensive agriculture and urban sprawl. There's no point in us addressing the pesticides issue if we don't simultaneously start treating bees with more respect, reducing atmospheric pollution and conserving/creating suitable habitat for bees and other pollinators.

So, what exactly ARE 'neonicotinoid' pesticides?

Neonicotinoids are a group of insecticides that include 'imidacloprid', 'clothianidin' and 'thiamethoxam'. They are neurotoxins (nerve poisons) that have been designed to attack the insect's central nervous system; causing paralysis and eventually death. Their target insects include vine weevils, aphids, whitefly, colorado potato beetle and termites.  As well as causing paralysis and death, neonicotinoids also produce other symptoms, (both in target and non target insects) such as interfering with the insect's navigation systems and, crucially, impairing their ability to groom themselves. (I'll come back to the grooming issue later)

Another insecticide, Fipronil, acts in the same systemic manner as the neonicotinoid group of insecticides.

Neonicotinoids were introduced in the early nineties and are now the world's most widely used group of pesticides.

N.B. Neonocotinoids are water soluble. Some, including the most widely used (Imidacloprid) remain in the soil for many years. Their high persistency in soil and water results in a sustained exposure to these pesticides, not only to bees, but to other non-target organisms and pollinators, including aquatic invertebrates, moths, butterflies and hoverflies and (indirectly) bats, amphibians and insect eating birds.  

"Neonicotinoid insecticides act by causing virtually irreversible blockage of postsynaptic nicotinergic acetylcholine receptors (nAChRs) in the central nervous system of insects. The damage is cumulative, and with every exposure more receptors are blocked. In fact, there may not be a safe level of exposure."  Dutch toxologist, Henk Tennekes

"Imidacloprid, Clothianidin and Fipronil exert sub-lethal effects, ranging from genotoxic and cytotoxic effects, and impaired immune function, to reduced growth and reproductive success, often at concentrations well below those associated with mortality. Use of imidacloprid and clothianidin as seed treatments on some crops poses risks to small birds, and ingestion of even a few treated seeds could cause mortality or reproductive impairment to sensitive bird species" Dr David Gibbons RSPB  

Which crops are treated with neonicotinoids?

Neonicotinoids are used as treatments on over 140 different crops including soy, corn, wheat, cotton, legumes, potatoes, sugar-beet, sunflowers, rapeseed and flax. Until 2011, they were used on the 740,000 acres of Californian Almond Trees. One third of all arable land in the UK now grows crops treated with neonicotinoids.

Less well known is the fact that 'Fipronil' (which works in the she way as the neonicotinoid insecticides) is used in flea treatments for dogs and cats.

How do neonicotinoids differ from other pesticides?

Until the introduction of insecticides such as neonicotinoids we were able to see pesticides with our own eyes as they were being sprayed as foliar applications onto our crops. Neonicotinoids, and some other groups of modern pesticides, work in a very different way. As well as being applied as foliar applications, they are also applied as seed dressings and soil treatments. These are less obvious than foliar applications, so many people, including some farmers, are unaware that they are even using them. Also, instead of being used reactively (i.e. after a problem has been identified) neonicotinoids are used 'prophylactically' which means crops are treated as a matter of course to safeguard them against the possibility of an attack by the pesticide's target insect. This is like human beings taking antibiotics all year round to protect us from the possibility of succumbing to a sore throat or flu.

The biggest difference between neonicotinoids and all other pesticides is that neonicotinoids work  'systemically'.  This means that once the seed (or the soil in which the seed has been planted) has been coated/treated with the insecticide, that insecticide is then taken up through the entire plant via it's vascular system.  So, it ends up in the plant's roots, stem, leaves, flowers, fruit, sap (guttation), pollen and nectar.....and it - does - not - wash - off.

We are told by DEFRA and by the agri-chem industry that this is ok. It is, apparently, 'safe' for bees and other pollinators to forage on crops whose seeds have been treated with neonicotinoids because they only ingest the pesticide in sub-lethal doses i.e. 'doses not large enough to cause death'. This might be ok if each bee only visited one plant and took one dose of 'sub-lethal' pollen in it's life time - but this, of course, is not the case.

How do neonicotinoids affect bees?

The introduction of neonicotinoids has coincided with honeybees dying in their billions and it has been known for at least 5 years, since Professor Joe Cummins wrote  this report  that they are likely to be one of the causes of CCD (colony collapse disorder). Unfortunately, despite there being a mountain of evidence stacking up against neonicotinoids, it is still an uphill struggle trying to persuade the 'powers that be' in the UK and in the USA to act on behalf of our beleaguered pollinators. In the mean time, the bee population continues to plummet.

Over a period of time, as it forages for pollen and nectar from neonicotinoid treated crops, each bee ingests a significant amount of 'sub-lethal' doses of neonicotinoids. Bees also take pollen and nectar from the treated crops back to the hive (honeybees) or nest (bumblebees and solitary bees) to provision their larvae.

A great many scientific reports have now been published showing evidence that a build-up of this pesticide over a period of time impairs the bee's nervous system (interfering with it's navigation system so it can't find it's way back to the hive after foraging) and it's immune system.

It is also known, but not as well reported, that neonicotinoids impairs the ability of bees to groom themselves. Indeed, Bayer CropScience boast about the effectiveness of their product  Premise 200SC  (active ingredient Imidocloprid) which interferes with a termite's natural ability to groom itself....therefore making it more susceptible to disease caused by microorganisms and fungi. If Imidacloprid interferes with a termite's ability to groom itself, it will also interfere with a bee's ability to groom itself....inevitably making it more susceptible to varroa mite. A double whammy for the poor honeybee.

To understand more about the grooming issue please listen to this excellent interview with Amanda Williams on the Barefoot Beekeeper website  

More effects reported in recent scientific reports

I mentioned earlier that new scientific reports have been published recently.

The first was written by Dr Jeffrey Pettis of the US Department of Agriculture. Dr Pettis showed that bees exposed to microscopic doses of neonicotinoids were much more vulnerable to disease. This report, bizzarely, was only published earlier this year.....a full two years after the research had been completed.

The second report, published at the beginning of April 2012, came from the University of Stirling's Professor David Goulson. It showed that "Growth of colonies of the common buff-tailed bumblebee, Bombus terrestris, slowed after the insects were exposed to field-relistic levels of imidacloprid, a common neonicotinoid insecticide. The production of queens, essential for colonies to continue, declined by a massive 85% in comparison with unexposed colonies used as controls.

"Given the scale of use of neonicotinoids, we suggest that they may be having a considerable negative impact of wild bumblebee populations across the developed world" the Stirling team said.

Do, please, watch this important short video of Prof Dave Goulson talking about the Stirling team's findings

Please also watch this short video about Bee deaths in France.  

Can we do anything to help?

With such overwhelming evidence against neonicotinoid pesticides it beggars belief that they have not yet been banned by the UK government. I cannot understand how seemingly intelligent people can reach positions of such power - yet be so blind to the horrors of these chemicals. Those in power are, I suppose,  more concerned with short term profits and 'economic growth' than the long term health of our pollinators and struggling eco-systems. Very short sighted.

There was some hope, when Professor Bob Watson, Chief Scientific Advisor to DEFRA, announced (after the publication of the Stirling University report) that he would review the evidence and reassess Defra's current stance on neonicotinoids, but unfortunately this review ended up in with Government scientists advising that  neonicotinoid pesticides should not be banned despite four scientific studies strongly linking them to sharp declines in bees around the world.

Equally unfortunate, is the fact that even when/if a ban is imposed upon the entire family of neonicotinoid insecticides, we will still be left with a crazy, mixed up Pesticides Regulatory System....where the responsibility to prove pesticides safe seems to rest with the pesticides companies that manufacture them. 

So, in the mean time, whilst we wait for the 'powers that be' to wake up and come to their senses, we can help speed up the banning of this particular group of pesticides by doing the following.....

1. Email your MPs asking them to put pressure on the Secretary for the Environment, to vote for a ban on neonicotinoids as proposed by the European Commission. Excellent advice on who to contact and what to write here -

2. Here are some lists of products containing neonicotinoids so you can avoid using them in your home and garden -

3. The Soil Association have published a letter that you can use to write to retailers asking them to remove products containing neonicotinoids from their shelves -

4. Follow journalist Michael McCarthy's articles in the Independent. He deserves a medal for the reporting he has done on this issue!  -

5. Check the provenance of all your seeds and plants to make sure they have not bee produced from neonicotinoid coated seeds or in soil treated with neonicotinoids. Buying from a trusted organic source is the safest way to ensure this.

6. Sign Neal's Yard petition asking our government to ban the use of neoicotinoid pesticides

A few last thoughts on the subject....

I do hope I haven't over faced you with too much information. Or not given given sufficient. I've tried to make this as basic and easy to understand as possible but it's a tricky issue to get your head around. I must stress that I have written this article based on the conclusions I have reached myself, having read dozens of peer reviewed scientific papers, reports and articles that speak both for and against the use of neonicotinods.

I am well aware that if/when neonicotinoids are banned then new ways must be found to protect the world's mono crops from pests. Unfortunately, our reliance upon just a few crops to feed the world has put us in a very precarious position. Large scale, intensive monoculture farming relies on ever more toxic herbicides, fungicides, and insecticides to keep it going. Ironically, the end result is that the food we are eating probably contains more chemicals than nutrients.

Small scale, organic farming, with its more diverse range of crops, is the only sustainable way forward, but we need some stepping stones to take us from what we have created to where we need to go next...........

Thank you for reading this blog. If anyone has further information or useful links please do post them as comments. 

Brigit x

P.S. This blog was written back in 2012. Far more research has since been published which leaves me even more concerned about the effects these insecticides are having upon our wildlife. For up to date information please follow Professor Dave Goulson's Blog and Matt Shardlow's blog - both are far more qualified and informed than I am to write about Neonicotinoids.

There is also now an EU temporary, partial restriction on 3 of the neonicotinoid insecticides. This restriction is being contested in the EU courts by Bayer & Syngenta who produce the insecticides. 

Some interesting links......

Video showing 'guttation' from neonicotinoid treated maize killing bees -

'A Disaster in the Making': Hugely important research by Henk Tennekes -

Neonicotinoid Pesticide Toxicity Profile -

Harvard University March 2012 report on Neonicotinoids and CCD

Buglife Report 2009 -

Pesticides Action Network UK -


  1. This comment has been removed by the author.

  2. A superb article - thank you.

    While not wanting to belittle the impact on bees and other wildlife (it's hugely important!) I am concerned about what these pesticides are doing to humans, especially children. When my children were small (decades ago!) it was discovered, after several very painful years, that they were "intolerant" of pesticides in food. They had uncontrollable diarrhoea and incontinence - and one was already on the waiting list to see an educational psychologist (diagnosed by a paediatrician as having a psychological problem!) when the cause was finally discovered. The eldest still can't tolerate certain things (grapes and wine being among the worst).

    I will certainly find time to look at your links and find out more and do what I can to help.

    Thank you for the time you spent in putting this together!

    1. Thank you for reading this and for your comments Wendy. I'm afraid I haven't any information on what these insecticides are doing to humans....but there may be something on the PAN website.

      Also, if you haven't already come across Georgina Downs, you may be interested in her campaign/website -

      B x

  3. Well written Brigit.

    It's about time the rest of the world woke up to these pesticides. Amazing that Germany has banned a product from a German manufacture, but the UK fails to see the same connection. I have a Warre style hive and hope to gain some 'residents' this year.

    1. It is indeed a strange thing that Germany have taken action against a german company but the UK haven't.

      Good luck with your Warre hive! I have been observing a wild swarm for a couple of years in an ancient oak near my home - and am trying to decide whether to get a Warre or Top Bar hive in the hope that they may swarm this year and take up residence...

      B x

  4. Hi Brigit - great piece - I just want to point out this new letter with far greater detail and a call for people to email Bob Watson

    1. Brilliant...thanks Amanda...I'll add the link now x

  5. Thanks for these valuable info. More power!

  6. I wonder why most of the talk about neonicotinoids applies to bees and there is so little mention or studies about beneficial insects of all sorts. Birds need insects; an important protein source for their babies. It bothers me that his is not taken more seriously.

    1. This worries me too Beatriz. There's some useful information on this site about the connection between neonicotinoids and bird decline -

  7. Thanks for a very interesting and informative piece
    have you seen this from Guy Watson:

    1. Will check out this link now Philip...thank you

  8. We were shown 'Who Killed the Honey Bee?' the other evening. Looking you up I found this blog post, which is very interesting and informative as it is a topic I am trying to find out more about.

  9. Hi Karin, I'm glad you found it interesting. I hope the links help you with your research...

  10. Thankyou very much for this interesting and informative article!

    1. Thank you for taking the time to read it Leonora! x

  11. Great read, and very well written and referenced. Keep up the great work. :)

  12. Excellent article - clear, simple and to the point. Fab!!

  13. I am stunned, so are the bees, as a long term agriculture forestry Hydrology soils and with Geology so geochemical soils aware and with farm (grandfather) garden family and bees grandfather connections it is beyond my comprehension as to why anybody would put pesticide coatings on seeds. Oil seed rape as noted BBC may be important Cash Crop for layover and industrial oil, but it is hardly a necessity that needs that sort of care. I also note the other plant seeds coated. I see no need at all for such extremes, as Soils started there are many Research University aspects which would show alternative means such as plant compatibility to soil zones. As water rseearch I am obviously appalled that having convinced there should be a reduction that we now have more persistent forms of chemicals, ones that could be transferred in biochemical mutations in time. Thanks BBC and your sites read, it appears from my review that these are what we would effectively call biological warfare substances in terms of their actions which have no specific target, general plastering of insect responses and thus affecting more than bees ? I have seen some papers but cannot read Wiley they expect lots of money for already tax paid research prints, many of which are relevant in my own work and were definitely paid for by government and University not privately as I know they are basic texts and references, that is they are already public access legally. Such is Wiley but then I am in all out confrontation with thme for this as it is. How can we be rational (a request from D Cameron) when we the Science are banned from our own works events of our own success decades. No wonder stuff like neonicotinoids gets through. Only Governments have secrets, not us, our research is Open System accessible but then Maggie wanted more money, even from poor people overseas and tried to have the lot of us banned while the sales progress. This is our work. They made Quota systems not us. I do not mind being paid in a rational legal manner, I object to people being ripped off and bees killed. I shall pursue good biology and chemistry lines of enquiry immediately as I have on hand top quaity experts and maybe we see if these substances may also be damaging to people, then start a fuss. Thanks Mike Stagg Hydrology Geology soils.

    1. Thank you for your comments Mike. I would be extremely interested to hear if you find anything about these substances being damaging to people via your lines of enquiry...

  14. Your post really helpful for my Pesticides Market Research and development.

  15. Is there a list of the 140 different crops neonicotinoids are used on? Please email to

  16. Brilliant post,thanks so much for all your research. here in NZ all the insecticides are being used with no consideration to any pollinator or living creatures, including humans !!
    I teach beekeeping and am also involved with organizing our first Natural Beekeeping conference in June, would I beable to use your info, credited to yourself of course ? I am gathering as much info as I can at the moment, you have written about this awful insecticide so well I am sure it would be of tremendous interest here.
    Thanks so much again ..bless our bees !

  17. I am having difficulty in corrolating the devastating effect that neonicotinoids are supposed to be having on honeybees with my own experience of the situation. I have been a beekeeper for over 60 years and for many of those years was employed to look after over 300 colonies.
    I have had my own bees for 56 years running, at one time, 70 colonies.
    I first dicovered varroa in my colonies in 1995 and since that time, when I have successfully managed the mite, I have had one of the best periods since I started beekeeping. I have had record honey takes, twice what I was getting in the 70`s and 80`s and triple what they were in the 50`s and 60`s. Average colony losses have been below 7% (excluding the two years when I did not treat for varroa when my losses were 33% and 56%!!)with no losses at all during seven of those years.
    I know many beekeepers and the pattern seems to be the same with most of them ie varro arrives then two years later colonies collapse with symptoms similar to those reported as "CCD". When they treat properly and at the correct time of year they have few problems.
    Many counties in the south of England have reported collecting record numbers of swarms over recent years, a good indication that there are plenty of strong healthy colonies about. I know of a colony in atree that is now it its fifth.
    I know this is anecdotal evidence but it convinves me that the varroa mit with its associated viruses is the main culprit for large scale colony losses.
    Treating bees with doses of neonicotinoids, which have little relevance to the ammount they may encounter in a very short ( 5 days average) foraging life span, and demonstating this may have a detrinental effect on them does not, in my opinion, in any way justify they should be banned at this moment in time.
    If ytou fed a person enough carrots they would kill him/her!!

  18. This is obviously of great concern, but also is the importation of bumblebees from foreign lands to pollinate our crops. This includes the commercially available UK strain Bombus terrestris audax. New bee pathogens could have long term irreversible consequences to our native species.

    1. The importation of bumblebees to pollinate out tomato crops etc is something I am also extremely concerned about and always include in my talks. I know a little about crithidia bombi but it's difficult to find information other than second hand reports about this issue without paying to have sight of the original research. If you have any pointers/links that I could refer to I would be extremely grateful to know of them! Thank you.

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  21. a more useful list of products containing neonicotinoids:

  22. You have clearly demonstrated a lack of knowledge in your opening paragraphs by stating Fipronil is categorised as a neonic. Nitenpyram (which is actually a neonic) is more widely used a flea and tick control than fipronil. Also, not all neonics are persistent "for many years" in the environment; many have a short half life. Foliar applications are also more frequently used than seed treatments or soil applications. You really should research before you go blogging. You're doing untold damage to farmers, industry and giving the public an uninformed interpretation. I understand that you did also state this is your opinion in an early passage, nonetheless you have inaccuracies a-swathed through you argument.

    1. Dear Anonymous,

      Many thanks for your comments, which I have taken on board. I have adjusted my post (which I wrote over 2 years ago) accordingly.

      Since writing this blog post I have done a lot more research, and have to say I am more convinced than ever that theses insecticides are doing long term damage not only to bees, but to other wildlife and to entire eco systems.

      I cannot reconcile the dangers of the long term damage neonicotinoids are causing with the (massive) short term profits they provide their producer's and manufacturer's shareholders. Not do I believe that farmers are being correctly informed - indeed much of the advice they receive comes from agronomists, many of whom are paid by the agrichem industry -

      I am not naturally someone who relished any kind of conflict, in fact I usually avoid it at all costs. A part of me would therefore chose to remain quiet and not publish my thoughts on this, or other issues I am concerned about. However, if I did that I would not be able to live with myself. People are free to do their own research on this and any other issue….and to draw their own conclusions. I would rather people questioned the use of these neuro-toxins than continue to believe they are safe just because the agrochemical industry (and the UK Govt) says they are safe. Too many vested interests going on there from what I can see.

      I would rather die knowing that I had spoken up for what I believe than sit at home complaining about things and doing nothing about them. I am very grateful to anyone who has the courage to speak out for a better world and wonder where we would be, for instance, if no-one had ever questioned the safety of DDT?

      I respect your beliefs, but I disagree that I'm 'doing untold damage to farmers and giving the public an uninformed interpretation'. Most of what I say is backed up with extremely 'informed' research and scientific evidence. Without pollinators, most of our insect pollinated crops would suffer and farmers would lose their livelihoods, so we need to look for other ways to produce food before we end up having to use hunan pollinators as they do in China. Would that someone had spoon up there about pesticides before it was too late!

      As for doing 'untold damage to industry', I don't know which industry you mean? If the agri-chem industry, then I would argue that the health of the planet is far more important than the health of a giant multinational industry and its shareholders.

      You have an advantage as I do not know your name or anything else about you.

      If you have time, maybe you would read Prof Dave Goulson's blog posts and see what you think of his research….

      Yours sincerely,