New kind of pesticide, widely used in UK, may be helping to kill off the world's honeybees

A bee collecting pollen hovers above a golden rape bloom. AFP

By Michael McCarthy, Environment Editor
Thursday, 20 January 2011

A new generation of pesticides is making honeybees far more susceptible to disease, even at tiny doses, and may be a clue to the mysterious colony collapse disorder that has devastated bees across the world, the US government's leading bee researcher has found. Yet the discovery has remained unpublished for nearly two years since it was made by the US Department of Agriculture's Bee Research Laboratory.

The release of such a finding from the American government's own bee lab would put a major question mark over the use of neonicotinoid insecticides – relatively new compounds which mimic the insect-killing properties of nicotine, and which are increasingly used on crops in the US, Britain and around the world.

Bayer, the German chemicals giant which developed the insecticides and makes most of them, insists that they are safe for bees if used properly, but they have already been widely linked to bee mortality. The US findings raise questions about the substance used in the bee lab's experiment, imidacloprid, which was Bayer's top-selling insecticide in 2009, earning the company £510m. The worry is that neonicotinoids, which are neurotoxins – that is, they attack the central nervous system – are also "systemic", meaning they are taken up into every part of the plant which is treated with them, including the pollen and nectar. This means that bees and other pollinating insects can absorb them and carry them back to their hives or nests – even if they are not the insecticide's target species.

In Britain, more than 1.4 million acres were treated with the chemical in 2008, as part of total neonicotinoid use of more than 2.5 million acres – about a quarter of Britain's arable cropland.

The American study, led by Dr Jeffrey Pettis, research leader at the US government bee lab in Beltsville, Maryland, has demonstrated that the insects' vulnerability to infection is increased by the presence of imidacloprid, even at the most microscopic doses. Dr Pettis and his team found that increased disease infection happened even when the levels of the insecticide were so tiny that they could not subsequently be detected in the bees, although the researchers knew that they had been dosed with it.

Dr Pettis told The Independent his research had now been put forward for publication. "[It] was completed almost two years ago but it has been too long in getting out," he said. "I have submitted my manuscript to a new journal but cannot give a publication date or share more of this with you at this time."

However, it is known about, because Dr Pettis and a member of his team, Dennis van Engelsdorp, of Penn State University – both leaders in research focusing on colony collapse disorder (CCD) – have spoken about it at some length in a film about bee deaths which has been shown widely in Europe, but not yet in Britain or the US – although it has been seen by The Independent.

In The Strange Disappearance of The Bees, made by the American film-maker Mark Daniels, Pettis and van Engelsdorp reveal that they exposed two groups of bees to the well-known bee disease nosema. One of the groups was also fed tiny doses of imidacloprid. There was a higher uptake of infection in the bees fed the insecticide, even though it could not subsequently be detected, which raises the possibility that such a phenomenon occurring in the wild might be simply undetectable.

Although the US study remains unpublished, it has been almost exactly replicated by French researchers at the National Institute for Agricultural Research in Avignon. They published their study in the journal Environmental Microbiology and said: "We demonstrated that the interaction between nosema and a neonicotinoid (imidacloprid) significantly weakened honeybees." …

Exclusive: Bees facing a poisoned spring

0 comments :

 

Blog Template by Adam Every . Sponsored by Business Web Hosting Reviews