A ban on five neonicotinoid pesticides enters into force in France on Saturday, placing the country at the forefront of a campaign against chemicals blamed for decimating critical populations of crop-pollinating bees.

The move has been hailed by beekeepers and environmental activists, but lamented by cereal and sugar beet farmers who claim there are no effective alternatives for protecting their valuable crops against insects.

With its ban, France has gone further than the European Union, which voted to outlaw the use of three neonicotinoids — clothianidin, imidacloprid and thiamethoxam — in crop fields.

Heavily agriculture-reliant France banned these three neonicotinoids plus thiacloprid and acetamiprid, not only outdoors but in greenhouses too.

These are the only five neonicotinoid pesticides hitherto authorised for use in Europe.

Introduced in the mid-1990s, lab-synthesised neonicotinoids are based on the chemical structure of nicotine, and attack the central nervous system of insects.

They were meant to be a less harmful substitute to older pesticides, and are now the most widely-used to treat flowering crops, including fruit trees, beets, wheat, canola, and vineyards.

Studies has shown that neonicotinoids harm bee reproduction and foraging by diminishing sperm quality and scrambling the insects’ memory and navigation functions.

Exposure also lowers their resistance to disease.

Some research has suggested that — like nicotine for humans — neonicotinoids hold an addictive attraction for bees, which shunned healthy food for pesticide-laced treats in lab tests.

The ban pitted French agriculture minister Stephane Travert, who lobbied for an easing, against environment minister Nicolas Hulot who refused to back down.

Hulot resigned on Tuesday, saying he felt “all alone” in the government on environmental issues.

Earlier this month, Canada announced plans to phase out clothianidin and thiamethoxam.

The French ban allows for case-by-case exemptions on the use of acetamiprid until July 1, 2020.

(AFP)