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.
- Bees at risk -
In recent years, bees started dying off from "colony collapse disorder," a mysterious scourge blamed partly on pesticides along with mites, viruses, and fungi, or some combination of these.
Scientific studies have since 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 UN has warned that nearly half of insect pollinators, particularly bees and butterflies, risk global extinction.
This is particularly concerning in the context of a 2016 study which found that about 1.4 billion jobs and three-quarters of all crops depend on pollinators, mainly bees, which provide free plant fertilisation services worth billions of dollars.
Some French farmers are angry over the ban, however, and say there is not enough evidence that neonicotinoids are responsible for bee decline.
"A large number (of agricultural producers) find themselves at a dramatic technical dead-end," a collection of farmers' bodies said in a joint statement calling for exemptions in sectors "where there are no alternatives, or insufficient ones" to neonicotinoids.
The ban, the groups claimed, "will exacerbate unfair competition with European and non-European producers" still allowed to use the pesticides.
A report by France's ANSES public health agency said in May there were "sufficiently effective, and operational" alternatives to the majority of neonicotinoids used in France.
- Not enough -
Some believe the measures do not go far enough.
"We should not limit ourselves to this family" of pesticides, argued Francois Veillerette of environmental lobby group Generations Futures. "Many others need banning too."
Many are concerned that neonicotinoids will continue to be authorised for use in non-agricultural pest control, such as in flea collars for pet cats and dogs, or in household fly traps.
The ANSES said in a report in February these products pose no risk to human health, provided they are used as specified.
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.