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 -