The NFU has reacted to new research showing widespread exposure of bees to pesticides by highlighting that the researchers admit they don’t know what effect it is having on numbers.

Published last month in Environment International, the research carried out by scientists at the University of Sussex looked at concentrations of insecticides and fungicides in pollen collected by bees.

Led by Dave Goulson, the team was investigating the potential exposure of bumblebees and honeybees to pesticides in pollen from oilseed rape crops and wildflowers growing near arable fields.

See also: Honeybees can recover from neonicotinoid damage in the wild

“Our data shows that the pollen of oilseed rape crops is contaminated with a broad range of pesticides,” they concluded.

These pesticides included spiroamine, carbendazim, neonicotinoids thiamethoxam and clothianidin, and a range of fungicides such as trifloxystrobin.

Although these chemicals have been detected in pollen before, the researchers said the study was the first to provide data showing the presence of this mixture of pesticides in bee-collected pollen.

These pesticides were also found, although at slightly lower concentrations, in pollen from wildflowers growing next to neonicotinoid-treated crops in UK farmland.

NFU chief horticulture adviser and bee health specialist Chris Hartfield said: “The study clearly says that while traces of neonicotinoids and other pesticides are found in a variety of wild plants fed on by bees, the researchers don’t know what effect this exposure is having on bees in the field.

“Technology is getting so advanced that we are increasingly able to detect the presence of substances in many places, but the critical question remains: does this exposure actually have an unacceptable impact on pollinator populations? This study is clear in saying that this question remains unanswered.”

However, Peter Melchett, policy director of the Soil Association, which partially funded the research, believes the results demonstrate that the use of safe-haven strips next to fields will fail.

He explained that to combat bee decline, the government’s pollinator strategy has focused on creating safe havens for bees by increasing flower habitats next to fields.

“This research suggests these supposedly safe havens are actually potentially dangerous chemical cocktail bars,” he said.

Therefore, the pressure group is calling for a full ban on neonicotinoids for all crops, extending the current ban for neonicotinoid seed treatments for oilseed rape and maize.

Mr Hartfield added that while the NFU, like other organisations, is very concerned that there have been significant declines in the biodiversity of bees and other pollinators, the evidence shows the most drastic declines are historical and happened decades before neonicotinoids were introduced.

“The general consensus of the scientific community remains that declines in bee and pollinator populations aren’t due to a single factor – the issue is multifactorial,” he said.

“The most recent, independent and comprehensive review of the evidence around neonicotinoids and insect pollinators concluded that the major gap in our understanding still remains whether or not harm caused by neonicotinoids results in widespread declines in pollinator populations.”

On top of this, the University of Sussex researchers said that the bulk of pesticides found in honeybee and bumblebee pollen were fungicides, which generally have low toxicity to bees.