bee cornflower
© Michael Probst
French bee keepers are up in arms over the authorisation of an insecticide they warn could sound the death knell of their already decimated bee population.

Bee hives have been hit in Europe, North America and elsewhere by a mysterious phenomenon called "colony collapse disorder". The blight has been blamed on mites, a virus or fungus, pesticides, or a combination of factors.

With the honey harvest in France down to just 10,000 tons this year - three times less than in the 1990s - the country's national apiculture union, UNAF, slammed what it called the "scandalous" authorisation of sulfaoxaflor, which attacks the central nervous system of insects. According to UNAF, sulfaoxaflor acts like a neonicotinoid, a pesticide based on the chemical structure of nicotine that many blame for being at least partially responsible for plummeting bee populations.

The European Union set down a temporary ban on the use of three out of five key neonicotinoids in 2013, and is mulling a permanent ban. France is due to outlaw them all from September next year, barring exceptional circumstances where no alternatives exist. "So why authorise a new one?," asked Gilles Lanio UNAF president. "It's shameful, scandalous, pitiful and irresponsible for future generations," he told Le Monde.

Studies have blamed the chemical for harming bee reproduction and foraging by diminishing sperm quality and scrambling memory and navigation functions. It has also been linked to lower disease resistance.

Neonicotinoids currently cover more than a fifth of French crops with 70 per cent of seeds from cooperatives already coated in the product.

Producers insist neonicotinoids are safe if used correctly. They also maintain that evidence linking these chemicals to a plunge in bee populations is flimsy and that the phenomenon is due to a number of factors, such as viruses and parasites.

Benoît Dattin, spokesman for makers Dow AgroSciences in France, said sulfoxaflor was at any rate not technically a neonicotinoid. "It's been authorised in 43 countries and used on millions of hectares and no negative impact on bees or pollinators has been signaled," he said.

The world's 20,000 species of bees play a vital role in fertilising more than 90 percent of the planet's 107 major crops.

Last year, the United Nations said 40 percent of invertebrate pollinators - particularly bees and butterflies- risk global extinction.

This week, researchers in Germany found that three quarters of flying insects in nature reserves across the country had vanished in 25 years, saying that agricultural pesticides may be to blame.

Entomologists have dubbed the drop "the windscreen phenomenon" as fewer and fewer insects end up squashed on car windscreens.

In September, a chief scientific adviser to the UK government warned that regulators around the world have falsely assumed that it is safe to use pesticides at industrial scales across landscapes and that the "effects of dosing whole landscapes with chemicals have been largely ignored".