In the Environmental Risks of Neonicotinoid Pesticides a review of the evidence post-2013 Goulson and Wood conclude that "exposure from non-target plants clearly represents a greater risk" to bee health, when looking at evidence from non-crop field margin plants.
They add another area of "greater risk" was "exposure to neonicotinoid-treated flowering crops has been shown to have significant negative effects on free flying wild bees under field conditions and some laboratory studies continue to demonstrate negative effects on bee foraging ability and fitness using field-realistic neonicotinoid concentrations."
The scientists said: "Within this context, research produced since 2013 suggest that neonicotinoids pose a similar to greater risk to wild and managed bees, compared to the state of play in 2013.
"Given that the initial 2013 risk assessment was sufficient to impose a partial ban on the use of neonicotinoids on flowering crops, and given that new evidence either confirms or enhances evidence of risk to bees, it is logical to conclude that the current scientific evidence supports the extension of the moratorium, and that the extension of the partial ban to other uses of neonicotinoids should be considered."
A Crop Protection Association representative said neonicotinoids were safe, adding: "The UN Food and Agricultural Organisation estimates that to feed a global population set to reach 9.5 billion by 2050 we will need to increase global agricultural productivity by 70 per cent," the spokesman said.
"Farmers will need to use every available technology – including pesticides – to ensure food production keeps pace with this burgeoning demand, while at the same time protecting the natural environment and conserving precious natural resources.
"It is estimated that there would be a 40 per cent increase in UK food prices without pesticides.
"Globally we already lose up to 40 per cent of our food every year to weeds, pests and diseases.
"Without pesticides, these losses could double and 60-70 per cent more land would need to be brought into production just to maintain current yields, with clear consequences for wildlife and the environment."