The NFU has questioned the results of a study suggesting a number of widely used synthetic pesticides harm moths, butterflies and birds as well as bees.
The European Commission placed restrictions on three neonicotinoid pesticides from December 2013, citing worries about potential impact on bees, but said it would review the situation within two years.
The European Academies’ Science Advisory Council (EASAC), a network of EU science academies that seeks to inform EU policymakers, has since assembled 13 experts to assess the relevant science.
In a new report, it has now claimed there is “an increasing body of evidence” that neonicotinoids, used in more than 120 countries, have “severe negative effects on non-target organisms”.
It also suggested the attention given to impact on bees - seen as the most important crop pollinators - had masked the effects on other pollinators such as moths and butterflies, as well as birds, which eat some pests.
Citing an increase in crops that require or benefit from pollination, the report noted “an emerging pollination deficit”.
Neonicotinoids are chemicals that act systemically, being absorbed and spread through the plant’s vascular system, which then becomes toxic for insects sucking the circulating fluids or ingesting parts of it.
Proponents say they have a major economic benefit because they destroy pests and help to ensure abundant food for a growing world population.
The report, however, cited the monetary benefits of protecting pollinators and natural pest controllers.
In reaction, the European Crop Protection Association (ECPA), which represents the pesticide industry, suggested the report was biased, and the NFU has now also added its criticisms.
Vice President Guy Smith said: “This research is not new and relies heavily on lab-based studies which are not reflective of what has been seen in the field.
“The motives behind the literature which has been studied are questionable; hence why the NFU continually lobbies for regulations to be based on balanced, sound science – not regurgitation of existing studies when new information is needed.
“The neonicotinoids restrictions have taken away a vital tool in the toolbox of UK farmers. Many farmers across the nation have seen their crops be compromised by cabbage stem flea beetle; a pest which was eating away at our plants before they even surfaced due to the absence of the neonicotinoid seed coating protecting the plant in its first growth stages.
“Its larvae are now inside many plants causing damage from the inside-out. We are yet to see the potentially destructive impacts of turnip yellow virus infections.”
He added that oilseed rape was an extremely important crop for pollinators including bees, providing an abundant, early, supply of pollen, and helping to create a varied habitat.
“Conversely, bees are essential to farmers in helping pollinate their crops,” he said.
“But with pests threatening acres of oilseed rape, it is likely farmers will reluctantly reduce the area of the crop grown or simply choose an alternative crop to grow.
“There is no evidence that the restriction has been beneficial to pollinators and the NFU remains concerned that it is politically motivated and the basis for it has oversimplified issues of pollinator numbers which is subject to multiple pressures such as varroa and habitat loss.”
The Commission welcomed the report and said it would start a review of new scientific information by the end of May.