Concern over Imidacloprid - Systemic Insecticide used on Oilseed Rape in UK

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This article is written by Graham White which is a digest of his letter sent to the UK Advisory Committee on Pesticides with regard to a systemic insecticide called IMIDACLOPRID.

Imidacloprid is produced by Bayer Crop Sciences and marketed in the UK under a variety of trade names including:

• 'Chinook' for seed dressing of oil-seed rape seed.
• 'Gaucho and Montur' for seed dressing of sugar beet seed.
• 'Prestige' for dressing of potato seed before planting.
• 'Confidor' for treatment through irrigation water in greenhouses (ornamental plants, tomatoes, cucumber and sweet pepper).
• ' Merit Forest' for treatment of forest plants against insect attacks.

I have confirmed the widespread use of 'Chinook' for oilseed rape and for sugar beet but have not been able to find out whether it is also used for potato sets, commercial greenhouses and forest plantations.

My concerns are threefold:

1. As a beekeeper I am concerned that we are beginning to see evidence of unusual collapse of bee colonies in the UK.
2. As a conservationist I am concerned that the large scale use of this highly toxic, systemic and persistent insecticide in the UK is effectively sterilising fields of all soil-invertebrate life including: earthworms, beetles, ladybirds, butterflies, moths etc. This has profound ecological implications, especially for insectivorous birds and mammals.
3. Imidacloprid is highly persistent in the environment and is absorbed into all parts of the crop-plant: pollen, nectar and seeds. If collected by bees it is progressively concentrated in honey as the nectar is evaporated. It seems likely that it will be present in sunflower and rape-seed oil, - even if in small quantities. As a neuro-toxin this may have implications for the food chain and human health.

Banned in France - Approved in the UK?
I became aware of Imidacloprid due to articles about massive loss of bee colonies in France, Switzerland, Sweden and Canada. I append a number of articles from government agencies, bee-research laboratories and other sources in those countries. Beekeeping is a very large and influential industry in France and concern at the economic loss from colony-deaths was very widespread. Large demonstrations were held in Paris and intense lobbying went on. The outcome was that the use of Imidacloprid as a seed-dressing for sunflowers, oilseed rape and potatoes was banned in France and it remains so.

Situation in the UK
When I consulted the Pesticides Safety Directorate online database and searched for the term ‘Imidacloprid’ I found just one reference to its approval as a seed-treatment for sugar beet (do try searching yourself). This implied that the use of this insecticide here in the UK was rather limited. However, after a great deal more searching on other sites I found that it is actually used on a truly massive scale as the dominant seed-treatment for oilseed rape, marketed under the trade name ‘CHINOOK’ in the UK or 'GAUCHO' in France. This discrepancy in the PSD database seems odd and I have emailed them directly to ask why this is so?

The obvious question is: why does a pesticide that has been banned throughout France continue to be approved for very wide scale use across the UK ? Moreover, why is it so hard to find in the PSD database?

Impact on Beekeeping in the UK
Currently there is growing concern in the UK about the unexpected collapse of bee colonies in summer (a time when they normally thrive) and a sporadic incidence of failure of queen bees to mate or prosper. As yet the evidence is anecdotal and a national survey/ study is urgently needed but if the pattern follows that observed in Sweden, France and Canada, it seems a reasonable hypothesis that Imidacloprid may be a causal factor. Imidacloprid is a systemic insecticide which attacks the nervous system of all invertebrates; the target pests are flea beetles and wireworms etc but beneficial species such as bees, earthworms and beetles are also killed. The pesticide is dusted onto seeds before they are planted and is used on a worldwide scale on crops including: sunflowers, oilseed rape, potatoes, wheat etc.

French and Swiss researchers found that after Imidacloprid is dusted onto sunflower seed, or oilseed rape, it permeates the entire plant, including the nectar, pollen and seeds. The loss of bee colonies in France was concentrated in sunflower or oilseed rape growing areas. Imidacloprid only needs to be present at 10 parts per billion to kill bees outright. Bees exposed to 5 ppb simply do not return to their hives.

A definitive Swiss study reported:

ABSTRACT:

“Klaus Wallner confirmed in his study of Imidacloprid prepared Phacelia with a burden of 50 g/hectare, that the bee’s honey-sac average contamination was 5ppb and the pollen taken from the 'pollen baskets' of the bees contained 7ppb. The centrifuged honey contamination level could not (yet) be ascertained. The level was less than the 3ppb trace ability level for honey.

Clarification in France:
In a report issued by the French Agriculture Ministry it was stated: According to the sunflower variety the residues in the flower on the 65th day (at start of blossom period) varied between 2.5ppb (Pharon) and 8.7ppb (Natil). These values could possibly be higher at point of harvest. The sunflower pollen is contaminated at an average level of 3ppb (up to 11 ppb max.). In untreated plantings (sunflower, rape and corn), which were planted in Imidacloprid-contaminated-soil, up to 7.4ppb was detected in the flowers.

“The Bayer study produced a mortality rate due to Imidacloprid for bees as follows: The LD 50 (the lethal dose which kills 50% of test organisms within 48 hours) lay between 3.7 and 40.9 Nanogrammes of Imidacloprid per bee. Long term injury was investigated by Bonmatin. He achieved an LD 50 after 8 days by feeding individual bees an Imidacloprid/ sugar solution of 0.1 ppb. The substance showed itself to be highly toxic when delivered over time.”

END ABSTRACT

Conclusion
I would be grateful if, in your capacity as a member of the Advisory Committee on Pesticides, you might raise this issue with your colleagues and convey to them the widespread international concern regarding this systemic pesticide, which has led to the ban in France and attempts to ban it in Canada. I append a number of documents and web site links. I would particularly recommend the PDF file from the 'Journal of Pesticide Reform' for a definitive scientific summary of ecological impacts and current lab research. Also the Swiss research appended as a PDF article is very concise. Graham White, 3 Oxenrig Farm Cottages, Lennel, Coldstream TD12 4EY 01890 882 713.

Update:12/10/05
I wrote to Dr Miles Thomas of the Central Govt Science Lab and asked him for current usage figures for Imidacloprid and formulations containing the chemical. See his reply below with figures which are not published yet but he seems happy to let us have them. I added the figures up and it comes to 734,203 hectares (over 1.5 million acres) of crops treated with Imidacloprid, or formulations including Imidacloprid in 2004. That is a truly massive amount of systemic insecticide. The actual report will give actual weights of pesticide involved.

"Hi Graham,
We have not yet published the report for the 2004 survey but it is nearly complete. We estimate the following seed treatment use:

Straight imidacloprid seed dressing
Sugar beet 114,948 ha

Beta-cyfluthrin/imidacloprid mixture
OSR 311,620 ha
Linseed 22,821 ha
OSR or linseed grown on set-aside 31,815 ha (29,537 ha OSR)

Bitertanol/fuberidazole/imidacloprid mixture
Cereals 196,568 ha

Fuberidazole/imidacloprid/triadimenol mixture
Cereals 33,963 ha

Imidacloprid/tebuconazole/triazoxide mixture
Cereals 12,468 ha

Regards Miles
--
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Dr Miles R Thomas Phone: +44 (0)1904 462 410
Head, Pesticide Usage Survey & GTN: 5129 2410
Knowledge Management Systems Fax: +44 (0)1904 462 253
Central Science Laboratory Email: m.thomas@csl.gov.uk
Sand Hutton York YO41 1LZ Web: http://liaison.csl.gov.uk
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Concern over Imidacloprid - Systemic Insecticide used on Oilseed Rape in UK

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