In a long-awaited assessment, the European Union’s food-safety agency has concluded that three controversial neonicotinoid insecticides pose a high risk to wild bees and honeybees. The findings by the European Food Safety Authority (EFSA) in Parma, Italy, raise the chances that the EU will soon move to ban all uses of the insecticides on outdoor crops.

In 2013, the EU prohibited applications of the three chemicals on crops attractive to bees — such as sunflowers, oilseed rape and maize — after an EFSA assessment raised concern about the insecticides’ effects. Since then, researchers have amassed more evidence of harm to bees, and the European Commission last year proposed banning all outdoor uses, while still allowing the pesticides in greenhouses. The latest EFSA assessment strengthens the scientific basis for the proposal, says Anca Pduraru, a European Commission spokeswoman for public health and food safety. EU member states could vote on the issue as soon as 22 March.

Neonicotinoids (often abbreviated to neonics) are highly toxic to insects, causing paralysis and death by interfering with the central nervous system. Unlike pesticides which remain on plant surfaces, neonicotinoids are taken up throughout the plant – in the roots, stems, leaves, flowers, pollen and nectar.

The EFSA assessment covered the three neonicotinoids of greatest concern for bee health — clothianidin, imidacloprid and thiamethoxam. The agency considered more than 1,500 studies, including all the relevant published scientific literature, and data from academia, chemical companies, national authorities, NGOs and beekeeper associations. The assessment found that the three chemicals posed at least one type of high risk to bees in all outdoor uses.

The agency found that foraging bees are exposed to harmful levels of pesticide residues in pollen and nectar of treated fields and contaminated areas nearby, as well as in drifting dust. It also concluded, on the basis of more limited evidence, that neonicotinoids can sometimes persist and accumulate in the soil, and so can affect generations of planted crops and the bees that forage on them.

"EFSA's advice is often criticized by interested parties such as NGOs and companies, but this is a good demonstration of how EFSA gives scientifically sound and impartial advice," says José Tarazona, head of the agency's pesticides unit.

A spokesperson for Syngenta, which produces neonicotinoids, says that the EFSA's conclusions are overly conservative. "When regulators make decisions about crop-protection products, what should matter is science, data and that the processes in place are respected and that the public interest is served," the spokesperson says. "Any further restrictions based on this report would be ill-conceived."

EU member states were scheduled to vote on the proposal to outlaw outdoor uses on 13 December, but postponed it partly because many wanted to wait until the EFSA completed its evaluation.

Member states plan to discuss the EFSA assessment at a meeting of the Commission's Plant Animal Food and Feed Standing Committee sometime in March, says the EC’s Pduraru. "The protection of bees is an important issue for the commission since it concerns biodiversity, food production and the environment."

This article is reproduced with permission and was first published on February 28, 2018.