A report from the European Food Safety Authority (EFSA) has suggested that neonicotinoids – insecticides used to kill unwanted pests – may also be harming bees, spurring calls for a ban on the pesticides.
In the report, more than 1,500 studies were analysed, looking at the effect of neonicotinoids such as clothianidin, imidacloprid, and thiamethoxam. They found that all outdoor uses of the substances indicated a high risk for bees.
Bees can be exposed neonicotinoids in a variety of ways, such as foraging nearby, while the soil can also be contaminated, leading to residues that end up on pollen. This was found to affect honeybees, bumblebees, and to some wild bees.
“The conclusions on risk varied according to factors such as the bee species, the intended use of the pesticide and the route of exposure,” the report noted. “However, taken as a whole the conclusions confirm that neonicotinoids pose a risk to bees.”
The EFSA said it was merely a scientific risk assessment body and thus was not able to recommend an EU-wide ban on the insecticides. However, The Guardian noted that it was likely they would be banned from all European fields next month when EU nations vote on the issue.
"Given that risk is considered confirmed it seems highly likely that neonics will be banned," Toby Bruce, a Professor of Insect Chemical Ecology at Keele University in the UK, said in a comment emailed to IFLScience.
He noted, though, that the it was not entirely clear from the report how much of a risk they were to bees. "High risk appears to be above a trigger level for causing an effect but how much of an effect is it?" he said.
Evidence has been mounting for the damage caused by neonicotinoids to bees in recent years, which have a similar chemical composition to nicotine. Some like the National Farmers’ Union have opposed the ban, however, saying alternative pesticides are much less effective.
Nonetheless, it looks like a ban is probably quite likely. Jose Tarazona, head of EFSA’s Pesticides Unit, said the amount of data available had allowed for detailed conclusions to be drawn.
“There is variability in the conclusions, due to factors such as the bee species, the intended use of the pesticide and the route of exposure,” he said in a statement. “Some low risks have been identified, but overall the risk to the three types of bees we have assessed is confirmed.”
About 2.5 million acres of farmland in the UK uses neonicotinoids. In November 2017, the UK environment secretary Michael Gove backed a ban on bee-harming pesticides, following a study that found three-quarters of flying insects had disappeared in Germany.
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