Pesticides made by Syngenta and Bayer pose a threat to honeybees according to the European Union's Food Safety Authority.
The EFSA say, in a special Opinion, that three neonicotinoid insecticides made by the companies are responsible: clothianidin and imidacloprid, produced by Bayer's agricultural unit Bayer CropScience, and Syngenta's thiamethoxam, the active ingredient in Cruiser OSR.
The researchers have found that residues of the pesticide remain in the pollen and nectar of plants, and therefore they should only be used on crops which honey bees do not feed upon, such as sugar beet. Sunflowers, rape seed and maize, for example would have to be excluded.
They point out that the pesticide could also be carried on the wind after cereal seeds such as wheat and barley, treated with the chemicals, had been sowed.
However, the scientists could find no definite causal link between the use of these pesticides and bee colony collapse.
"Due to shortcomings in the data, EFSA was unable to finalize assessments for long-term risks to colony survival and development... and therefore conclusions could not be drawn on colony collapse disorder," the opinion said.
The reaction of Bayer CropScience was to assert that the opinion does not alter the conclusions of previous EU assessments of its products, which found no unacceptable risks in their use.
These findings had been echoed by Britain's Food and Environment Research Agency, who said last year that there was no evidence that use of neonicotinoids could cause the collapse of whole bee colonies.
The use of neonicotinoids has been banned in Germany, France and Italy.
And a study from Harvard University concluded in April last year that neonicotinoids are likely the primary cause of colony collapse disorder.
According to lead researcher Chensheng Lu: “It apparently doesn’t take much of the pesticide to affect the bees. Our experiment included pesticide amounts below what is normally present in the environment.”
The EFSA has recently completed a review of all its activities related to bees. Its Guidance on the Risk Assessment of Plant Protection Products on Bees will be published in the spring of 2013.
A further Scientific Opinion on the risk in the EU of two bee parasites, the small hive beetle (Aethina tumida) and Asian bee mite (Tropilaelaps), is currently being finalised by its Panel on Animal Health and Welfare.
In Britain, Defra is still considering its own scientific opinion on the matter, which is that: ″low doses of neonicotinoids could have sub-lethal effects on bees with consequences for bee populations″.
Its dedicated website contains the latest information and advice for beekeepers and farmers.
The EFSA warns that bees will also be threatened by guttation, or the secretion of droplets of water or sap from the pores of treated plants.
EFSA’s conclusions contain tables listing all authorised uses for seed treatment of the three substances, indicating for each route of exposure: where a risk has been identified; where a low risk has been identified; or where an assessment could not be finalised because of a lack of data.
They propose a much more comprehensive risk assessment for bees, and a higher level of scrutiny for the interpretation of field studies.
They say that it is possible that similar risks apply to other pollinators as well, but they had insufficient data to consider this.
The findings have been dismissed by the European pesticide lobby ECPA, and the EU farmers' association COPA-COGECA. They claim that the treatment of seeds using these pesticides provides over €2bn a year extra in crop revenues and that banning them could jeopardise 50,000 farm jobs.
Europe is determined to work with biotechnology companies. Its Bioeconomy Strategy, Innovating for Sustainable Growth: a Bioeconomy for Europe’, envisages public-private partnerships with companies such as Monsanto and Syngenta to drive investment.
However, the Commission's health spokesman, Frederik Vincent, said: "As far as we're concerned it's quite clear. If the report and ensuing studies highlight that there is a problem with these products, then the Commission, together with member states, will take the necessary measures".
Syngenta is a signatory of the World Business Council for Sustainable Development (WBCSD)'s Vision 2050 document, which sets out how a global population of 9 billion can live well within the resource limits of the planet by 2050.
Its CEO, Michael Mack said upon signing it that: "humanity has largely had an exploitative relationship with our planet; we can, and should, aim to make this a symbiotic one".
Story: David Thorpe, News Editor