A widely-used group of pesticides has been ruled unsafe for bees, in a report that has raised concerns over the EU’s safety assessment process.

This week, the European Food Safety Authority (EFSA) found that three kinds of “neonicotonoid” pesticides ‒ clothianidin, imidacloprid and thiamethoxam ‒ could be damaging to honey bees, even when applied at “sub-lethal” levels, which could damage the bee colonies without killing them outright.

A lack of bees leads to a lack of pollination, which can decrease the quality and quantity of fruit and vegetable produce.

EFSA recommended that the harmful pesticides should only be used on crops that do not attract bees, but conceded that the findings needed more work to be entirely conclusive, and that the report had largely drawn its conclusions from existing research rather than a new study. 

This has worried environmental campaigners, who say that it proves neonicotinoids shouldn’t have been authorised for use in the first place.

“Given that there is no new data here, it is extremely worrying that these pesticides were authorised for use in the European Union in the first place,” said Joan Whalley MP, chair of the environmental audit committee.

“This raises important questions about the whole European pesticides assessment regime, which the Environmental Audit Committee will now be looking into.Defra and the UK Advisory Committee on Pesticides have previously stressed their confidence in the safety of these products so they must now examine EFSA’s risk assessment carefully before deciding whether UK farmers can continue to use these chemicals on crops.”

Bee numbers in Western Europe and the United States have been falling for over a decade, with suggested factors ranging from the impact of GM crops to mobile phone signals.