Study: neonicotinoid pesticides are killing bees


Bees aren’t just the makers of delicious honey, they play a crucial role in the world’s agricultural systems. But they are slowly vanishing – mainly due to loss of habitat and exposure to pesticides.

Pesticidesare present all around us, from the flowers in our gardens to our meals, our soaps and our swimming pools.

Insecticides are generally the most toxic pesticides, at least in terms of direct, short-term effects, according to the Pesticide Action Network.

Particularly controversial are neonicotinoids, a family of insecticides used to control destructive crop pests. In 2013, the EU restricted their use after detecting environmentally harmful effects – particularly on bees.

But the debate still rages between supporters of a full ban of neonicotinoids and those who defend their use.

The neonicotinoids controversy

A new study – financed by pesticide producer Bayer CropScience and Syngenta – supports previous evidence that the chemicals do have negative effects on bee colonies. 

But the companies argue the results do not show the whole picture.

The European Commission, meanwhile, is preparing to review limits on the use of neonicotinoids set out in 2013. By fall this year, these pesticides could be under much tighter control.

Pesticide over a crop (picture alliance / Dinodia Photo)

The use of pesticides has created controversy around the world

However, several studies have shown these pesticides reduce the fertility and the life span of bees and other insects.

Once the risk these products pose to biodiversity became clear, in 2013 the European Union restricted the use of three neonicotinoids – clothianidin, thiamethoxam and imidacloprid.

Opponents have argued that evidence for the restrictions came from studies conducted under artificial exposure conditions, and that the insects were exposed to higher levels of the pesticides that they would in the real world.

Life in the field

Now, German chemical company Bayer and agribusiness Syngenta have financed the first study of neonicotinoid effect on bee colonies at exposure levels typical in the field. 

The study was carried out in the UK, Hungary and Germany with three different bee species. In the first two countries, honeybee colonies’ success at overwintering was reduced after exposure to crops treated with neonicotinoids.

Labor - Hummel (Paul Fisher)

Scientists have analyzed three species of bees in three different countries

However, in Germany no harmful effects on overwintering honeybees were found. That’s partly because the UK and Hungary colonies had weaker health due to local diseases. But above all, they were feeding regularly on nearby oilseed rape crops treated with one of the pesticides restricted by the EU.

“Up to 50 percent of their food came from crops treated with pesticides,” Richard Pywell, co-author of the study, told DW.

This shows that despite the EU moratorium, there is a strong presence of these toxic substances in the fields, Pywell said.

However, Peter Campbell, head of research collaborations with Syngenta, told DW researchers have only published the negative effects, while the findings actually show many potential benefitial ones.

“The results are much more complex than the simplistic conclusion the researchers have presented,” Campbell said.

Biene - Lucy Holmes Osmia Bicornis-rufa (Paul Fisher)

Bees’ future may depend on upcoming political decisions

Economics vs. the environment

The European Commission plans to revise the ban on neonicotinoids to prevent them being used in any outdoor space, limiting them to greenhouses, Anca Paduraru, spokesperson for Health and Food Safety at the European Commission, told DW.

The European Commission will present the revised regulation mid-July to be approved by member states, and is hoping for a resolution by the end of November.

However, recent debate over the herbicide glyphosate has shown such processes tend to take longer than planned, particularly if large member states such as Germany drag their feet.

Experts fear Germany may prioritize the economic advantages of the pesticides over their environmental impact.

Pywell said he wouldn’t give a personal opinion on the controversial issue. “We are independent scientists and it is not our role to make political decisions,” he commented.

However, he highlighted the need for greater consistency between regulations in different EU countries.