David's blog posts tagged with 'insecticide'

The neonicotinoid saga continues



Yesterday saw publication of my review of the evidence for broader impacts of neonicotinoids on wildlife other than bees in the Journal of Applied Ecology. If you'd like to read it, please go to Goulson Lab publications page, scroll down, and click on the link to the pdf.

The key points are as follows:

1) Neonicotinoids are very widely used, and have extremely high toxicity to all insects and many crustaceans. They are commonly applied as a seed dressing to crops.

2) Most (<90%) of the active ingredient do NOT go into the crop, but get washed into the soil and ground water. They also leach into streams. Levels found in streams and California and the Netherlands commonly exceed lethal concentrations for aquatic wildlife. Data from UK waterways appear to be absent.

3) They have a half life in soil which commonly exceeds 3 years, meaning that they rapidly accumulate in soil if they are used annually. The effects of this on soil organisms and soil health are not understood.

4) Neonicotinoids have been found in field-margin vegetation, which is hardly surprising if they are accumulating in soils. Impacts of this on farmland wildlife such as butterfly caterpillars feeding on field margin vegetation have not been studied.

5) If dressed seeds are consumed by granivorous birds such as partridge, or by rodents such as voles, they need only eat a few seeds to recieve a lethal dose. During drilling, seed is inevitably spilled, but we do not know whether it is consumed by wildlife.

6) Evidence that neonicotinoid seed dressings actually increase yield is absent (or is not available for public scrutiny). Some US studies suggest that they have negligible benefit to farming. In short, modern farming practices do not seem to be EVIDENCE BASED, but are driven by marketing by the agrochemical industry.  

7) We seem to have forgotten all about Integrated Pest Management (IPM), an approach which emphasizes minimising pesticide use through monitoring of pest numbers, crop rotations, encouraging natural enemies etc... Instead we are simply using pesticides prophylactically.  

Although I supported the 2 year moratorium on use of neonics, which comes into effect in December 2013 (better than nothing), it is entirely unclear what it will achieve, or what will happen afterwards. Neonics will continue to be used extensively for non-flowering crops such as winter wheat. Even if we completely stopped using them they would be in soils for years to come. So any benefits from the partial moratorium will not be apparent in 2 years. In any case, there seems to be no plan to monitor the benefits, so if they did occur (which is unlikely) we wouldn't know.....

It is hard for most of us to make sense of what is going on here.....

 Dave Goulson's research lab website




USA finally considering action over neonicotinoids, spurred on by doubts as to whether they actually work



Two US Congressmen have launched a bill to suspend uses of neonicotinoid insecticides in the US, following the lead of the European Union. Representatives John Conyers of Michigan and Earl Bluemenauer or Oregon introduced the “Saving America’s Pollinators Act”. They were prompted by widespread honeybee colony losses and a major bumblebee kill in Oregon where 50,000 dead bumblebees were found beneath two lime trees as a result of their being sprayed with neonicotinoids for ornamental reasons (note that lime trees often have a few dead bumblebees under them for separate reasons that have never been fully explained). I was recently invited over to speak in Capitol Hill in support of this bill.   

The debate over neonicotinoids and bees rolls on and on, with new studies emerging every day. It seems to me that the evidence on bumblebees is clear and convincing - realistic doses are very likely to be doing harm to wild colonies – but the evidence for honeybees remains muddier. However, most of the studies finding no impact on honeybees have been funded by or performed by the industry that manufactures the chemicals, so murky waters are to be expected. 

My visit coincided with the launch of a fascinating review of the economic value of neonicotinoids, produced by the Centre for Food Safety, a US-based non-profit organisation. They review 19 studies that have evaluated how much neonicotinoid seed dressings (the usual way of using these chemicals) increase yield of a range of crops, including wheat, corn, soya beans, and oilseed rape. The findings are astonishing – in every case, the studies either found no benefit whatsoever, or weak and inconsistent benefits unlikely to offset the cost of the pesticide. As Dr Christian Krupke (a leading researcher on this topic at Purdue University) said to me, “There may be places in the US where the pests are so bad that farmers need neonicotinoid seed dressings, but we can’t find them”.

In short, the most widely used pesticides in the world - prophylactically applied to arable crops across the globe - appear to be ineffective, and to have been widely miss-sold. It reminds me a little of the Payment Protection Insurance scandal – farmers are advised to use seed dressings as an insurance against something which, it seems, almost never happens.

Remarkably, no similar studies seem to have ever been performed in the UK or elsewhere in Europe to evaluate how much, if at all, neonic seed dressings increase yield here. It would be easy to do – experimental plots of crops that are treated exactly the same, except for the presence or absence of the seed dressing. How did these chemicals come to be so widely used without the manufacturers demonstrating clearly that they worked? If they did perform such studies, why can nobody find them? Sceptics such as I might also point to Italy, where neonics were banned on corn some years ago and where yields have remained stable and corn farming profitable.   

For me, this turns the whole bee debate on its head. If neonic seed dressings were essential to grow crops, one might have to accept a risk of harm to bees. But it seems that they are not.

In Europe, a decision will need to be made in the next year or so as to whether the current EU moratorium is extended or allowed to lapse. This new evidence will hopefully help to prevent the latter.

Prof Dave Goulson, University of Sussex.

[An abbreviated version of this Blog is published in the newsletter of the BBKA, June 2014]

Are crops being devastated without neonicotinoid protection?



Response to article by Matt Ridley in the Times, 6 October. Note that the Times refused to publish a (shorter) response that I sent to them:

To: letters@thetimes.co.uk


Dear Sir,


On 6 October, the Times published an opinion piece by Matt Ridley on the impacts of the neonicotinoid moratorium on farming. These insecticides are the subject of a partial 2 year ban introduced by the EU because of the perceived risk they pose to bees. Ridley asserts that oilseed rape crops are now being devastated because they are not being protected by these insecticides, claiming that in some regions up to 50% of the crop has been lost. He argues that there is “literally no good science linking neonics to bee deaths in fields” and that the moratorium only came about because “green lobby groups… have privileged and direct access to... European officials”. He goes on to claim that there is no evidence that bees are declining, and that they will be worse off if there is less oilseed rape for them to feed on as a result of the moratorium. He even sneaks in a quick go at badgers, suggesting that they may be the main problem that bumblebees face. In short, he says the moratorium is a typical barmy bit of EU legislation that is crippling farming for no good reason, no better than the apocryphal EU restrictions on the shape of bananas.


I’m one of the scientists who have been conducting this “no good” science, so you might not be surprised to hear that I have a rather different view of the situation. The EU decision was taken only after a team of scientists at the European Food Standard’s Agency had spent 6 months reviewing all the scientific evidence. They concluded that neonics pose an “unacceptable risk” to bees, and hence a majority of EU counties voted for the moratorium. The UK’s Environmental Audit Committee, a cross-party group of MPs, came to the same conclusion, and urged our government to support the ban. The US Fish & Wildlife Service also concurred, and have banned use of all neonics on land they administer. Most recently, a team of 30 scientists, of which I was one, reviewed 800 papers on this topic and in a series of 8 articles published in the journal Environmental Science and Pollution Research, concluded that “The combination of prophylactic use, persistence, mobility, systemic properties and chronic toxicity [of neonicotinoids] is predicted to result in substantial impacts on biodiversity and ecosystem functioning”.


These neurotoxins persist in soils for years, and they are now known to be found in hedgerow plants, streams and ponds. One teaspoon is enough to deliver a lethal dose to 1.25 billion honeybees (it would kill half of them, and leave the others feeling very unwell).  But they do not just pose a threat to bees; any insect living on farmland or in streams that flow from farmland, and any organisms that depend on insects for food (e.g. many birds and fish) are likely to be affected.


The backdrop to all this is that over the last 60 years arable farming has become highly dependent on a blizzard of chemical inputs. Many crops are treated with twenty or more pesticides each year, and grown in vast monocultures with minimal use of rotations and negligible attention paid to encouraging natural enemies that can help to control pests.

There is little space left for nature. As a result, European wildlife populations are collapsing. RSPB’s 2013 “State of Nature” report summarizes the state of play, and it is bleak reading – most farmland wildlife groups for which we have data are overwhelmingly in decline. According to British Trust for Ornithology data, 44 million breeding birds vanished from the British countryside in the last decades of the 20th century.  


Conservation organizations are fighting a losing battle. To claim that they have “privileged” access to politicians is bizarre; never have green politics been so low on the agenda. It seems rather more plausible that those who profit from promoting intensive farming, particularly the agrochemical industry, are the ones with access to regulators and policy makers. Sales of neonics alone are worth $3billion pa, so that industry can afford to employ armies of lobbyists. Many EU countries have folded under pressure from industry and allowed farmers derogations to use neonics during the ban. Following the recent stories of oilseed rape losses in the UK, Defra have allowed farmers to spray different types of neonics onto their crops, while others have resorted to sprayed their rape seedlings up to 5 times with pyrethroid insecticides already this autumn, at the same time complaining that pyrethroids don’t work because the pests are resistant (so why use them?). In these circumstances the moratorium is worse than useless, but surely there is a better, more sustainable way forwards? We need to find ways to grow crops without damaging the environment. If rape cannot be grown in some areas without blitzing it with neurotoxins, then perhaps farmers should consider growing something else entirely? If they tried to wean themselves off their chemical dependency, introduced more diverse crop rotations, left small areas for wildlife, and tried to encourage natural enemies of their pests, they might find that their problems got better.


What of Ridley’s claim that oilseed rape crops are being wiped out because they are no longer protected by neonicotinoids? He is not the first to say this. In May, the NFU Vice President Guy Smith claimed on Farming Today that 70% of the Swedish spring oilseed rape crop had been wiped out by pests following the introduction of the neonic moratorium. This was wildly incorrect – when eventually official figures emerged, the yield was down just 5%. Two days ago Defra revealed official figures on the extent of the damage in the UK – 1.35% of the crop has been lost (http://www.hgca.com/press/2014/october/08/csfb-crop-losses-estimated-at-27-in-hgca-funded-%E2%80%98snapshot-assessment%E2%80%99.aspx). Note that some crops are lost every year, with or without neonics. So why would a senior politician (Matt Ridley is a tory Lord and brother-in-law to Owen Paterson) and VP of the NFU want to grossly exaggerate the damage, and hence by implication suggest that farmers cannot grow crops without neonics? This is not in the farmer’s best interests, or that of the environment, or that of consumers. One might be forgiven for wondering if they weren’t actually working for the agrochemical industry.


Finally, will bees suffer if farmers grow less oilseed rape because of the moratorium, as Ridley asserts? I doubt it. Bees need a steady supply of food through the year, not a four week spring glut followed by famine because there are few wildflowers. In any case, if you were offered a feast of food laced with a neurotoxin, or a more modest meal of unpoisoned food, which would you opt for? In a sense, that is the choice that we all face right now.


Dave Goulson is Professor of Biology at the University of Sussex. He is author of the bestselling A Sting in the Tale and A Buzz in the Meadow, the latter describing the neonicotinoid controversy.


“Bee Informed” – but not by this propaganda




Pop in to your local Homebase, find the long aisles where the plethora of garden pesticides are arrayed, and you will now find glossy leaflets prominently displayed with a picture of a bumblebee on the front, entitles “BEE INFORMED - WHEN USING INSECTICIDES IN YOUR GARDEN”. So far so good, I can’t really argue with that. But read on.

Inside the leaflet, you will learn that bees are important. Excellent stuff. Then you will be told that bee health has been compromised, and that “A number of culprits have been identified, including:

• Parasitic mites such as Varroa

• Bacterial, fungal and viral diseases

• Habitat loss and degradation

• Genetic factors”

All true, but you might be thinking that there is an obvious omission from this list. Read on, and you will learn that “Some claims have also been made of a possible link between the decline in bee populations and the use of some insecticides. This has not been shown scientifically”. Hmmm.

The “some insecticides” they refer to are presumably neonicotinoids, the controversial chemicals that have been at the heart of a ferocious debate for ten years or more. Neonicotinoids are the active ingredient in many garden insecticides, and you may well also drip them on the neck of your dog or cat to prevent fleas. A group of scientists at the European Food Standards Agency spent six months examining the safety of these chemicals, and concluded that they pose an “unacceptable risk”. As a result, a majority of European countries voted for a ban on several of the most widely used neonics on flowering crops that bees might visit (the UK government opposed, of course). Since then, a huge review of over 1,000 scientific papers was written by 28 scientists from all over the world (I was one), under the auspices of the International Union for the Conservation of Nature, and it concludes that neonics are harmful to bees and pose a serious threat to biodiversity. On top of that, The European Academy of Sciences published a huge report on the subject last year, written by a team comprising a leading scientist from every European state. Their findings echoed the earlier reviews; these chemicals are damaging to bees and other wild insects. None of this is particularly surprising; these are highly poisonous neurotoxins that kill insects of any sort in minute, near-infinitesimal doses. They are also highly persistent, sometimes lasting for years in soil and plants.       

So who produced this wildly misleading leaflet? The Crop Protection Association, the Horticultural Trades Association, and the British Beekeepers Association (BBKA). The first two come as no surprise; these are essentially wings of the agrochemical industry, pushing their poisons as usual. But the BBKA? Really? Shame on you.

The leaflet goes on to say that “Provided that garden care products are used as directed on the label, they will not pose a problem to bee health.” Yet a recent Swedish study, published in the most prestigious scientific journal in the world (Nature), showed huge impacts of neonics on bumblebees and solitary bees when the chemicals were used by farmers ‘as directed on the label’. Remember that, 50 years ago, the agrochemical industry assured us the DDT was safe, until it turned out that it wasn’t. Later, they told us that organophosphates were fine, except they weren’t. Do you believe them this time? I don’t. 

The simple truth is that none of the array of chemicals on sale in your local garden centre are necessary. I have a two acre garden that I manage singlehandedly, while having a full-time job, and I manage to grow heaps of flowers and veg. It isn’t the tidiest garden ever, but it looks wonderful (to me anyway!). Every year my broad beans are attacked by a horde of black bean aphids, but after a week or two an army of ladybirds, hoverflies, lacewings and tiny parasitoid wasps come to the rescue, and in no time they are gone. The bean plants look a bit dog-eared, but they recover and give a great harvest. No need for insecticides. I’m ashamed to admit I used to use glyphosate, and I still have an old pot of it in the shed still, but since the World Health Organisation announced that it is highly likely to be carcinogenic[1] I have stopped using it. Hoeing works just fine, and I have kids and pets in the garden.   

To be honest, I expect nothing else from the pesticide industry. They are a hugely powerful and rich lobby that spends a fortune trying to convince us that we need their products. But why does Homebase push their propaganda? I guess money is the answer. Why does the BBKA support it? Do their members agree? I’m pretty sure that most of them don’t. The senior management of BBKA have always had an oddly cosy relationship with the agrochemical industry, to the horror on many of the BBKA members who I have spoken to. I guess that money has changed hands at some point.

The leaflet also mentions the Royal Horticultural Society as a source of further information, though it is not clear if RHS endorse it. I sincerely hope not.

We should boycott Homebase until they stop displaying this leaflet (my boycott started today, but on my own I don’t think that will bring them to their knees). We should campaign for these chemicals to be withdrawn entirely from garden use. I would love to see ALL pesticides banned for use in the garden; there is just no need, no need at all.  


The leaflet can be downloaded from the Crop Protection Association directly here:


[1] Glyphosate, a herbicide, is the most widely used pesticide in the world. It is in most foods we eat. Recent studies have found significant levels of glyphosate in urine of almost every German of 2,000 tested, with the highest levels in children.