France bans Syngenta pesticide linked to bee colony collapse

by | Jun 4, 2012 | Agriculture, Biodiversity & Habitat Destruction, Toxification

By Jeremy Hance / Mongabay

Following research linking neonicotinoid pesticides to the decline in bee populations, France has announced it plans to ban Cruiser OSR, an insecticide produced by Sygenta. Recent studies, including one in France, have shown that neonicotinoid pesticides likely hurt bees’ ability to navigate, potentially devastating hives. France has said it will give Sygenta two weeks to prove the pesticide is not linked to the bee decline, known as Colony Collapse Disorder (CCD).

France’s decision comes after its National Agency for Food, Safety, and the Environment (ANSES) confirmed the findings of two recent studies published in Science. The two studies found that neonicotinoid pesticides, although not immediately lethal, likely hurt bee colonies over a period of time.

In the French study, researchers glued tiny microchips to free-ranging honeybees and then administered small doses of thiamethoxam, a primary ingredient in Sygenta’s Cruiser OSR to some of the bees. Bees exposed to the pesticide were two to three times more likely not to return from foraging trips, allowing researchers to hypothesize that the pesticide impairs the bee’s ability to navigate its surroundings successfully.

Because neonicotinoid pesticides work by impacting insects’ central nervous systems, they have long been a target for researchers trying to understand Colony Collapse Disorder, but the difficulty has been proving that pesticides harm hives even though they don’t kill bees outright.

However, Sygenta denies that their pesticides have played any role whatsoever in the bee collapse.

“All Syngenta’s crop protection products are thoroughly tested to ensure that there are no unwanted effects on beneficial insects such as bees or excessive residues in food or risks to human health,” the company says on its website.

The French government disagrees and has stated it would also raise the question of a ban on the pesticide for the entire European Union (UN).

Evidence of harm piling up

Despite Sygenta’s statements, studies continue to appear that find a link between neonicotinoid pesticides and Colony Collapse Disorder. Recently, researchers in the U.S. fed tiny doses of neonicotinoid pesticide-laced high-fructose corn syrup, which is commonly used to feed bees, to 16 hives in the field and left four hives untreated. For months all the hives remained healthy, but after around six months over 90 percent (15 out of 16) of the hives fed with the pesticidal corn syrup had collapsed, while the four control hives remained healthy.

“There is no question that neonicotinoids put a huge stress on the survival of honey bees in the environment,” lead author Chensheng (Alex) Lu, an associate professor at the HSPH, told mongabay.com.

Meanwhile another U.S. study published last month in the Journal of Experimental Biology, found that bees hit by neonicotinoid pesticides underwent behavioral changes. Exposed bees only fed on very sweet nectar, ultimately limiting their feeding choices. In addition the bees ability to communicate was injured.

Foraging bees communicate via ‘waggle dances’ whereby they show the hive where to find food sources. But says lead author Daren Eiri, “Remarkably, bees that fed on the pesticide reduced the number of their waggle dances between fourfold and tenfold. And in some cases, the affected bees stopped dancing completely.”

Scientists first started recording alarming declines in bees in North America in 2006. Shortly thereafter similar declines occurred throughout Europe, and have also been noted in Taiwan. While periodic colony collapses have been recorded since the 19th Century, the current crisis has proven much worst than past ones with some producers losing 90 percent of their hives. A number of theories for the collapse have been posited, including disease, parasitic mites, habitat loss, and, of course, pesticides. Many researchers have suggested a combination of these factors.

Studies link common pesticides to 50% decline in honeybee populations

by | Mar 30, 2012 | Agriculture, Biodiversity & Habitat Destruction, Toxification

By Damian Carrington / The Guardian

Common crop pesticides have been shown for the first time to seriously harm bees by damaging their renowned ability to navigate home.

The new research strongly links the pesticides to the serious decline in honey bee numbers in the US and UK – a drop of around 50% in the last 25 years. The losses pose a threat to food supplies as bees pollinate a third of the food we eat such as tomatoes, beans, apples and strawberries.

Scientists found that bees consuming one pesticide suffered an 85% loss in the number of queens their nests produced, while another study showed a doubling in “disappeared” bees – those that failed to return from food foraging trips. The significance of the new work, published Science, is that it is the first carried out in realistic, open-air conditions.

“People had found pretty trivial effects in lab and greenhouse experiments, but we have shown they can translate into really big effects in the field. This has transformed our understanding,” said Prof David Goulson, at the University of Stirling and leader of one of the research teams. “If it’s only one metre from where they forage in a lab to their nest, even an unwell bee can manage that.”

Prof Mickaël Henry, at INRA in Avignon, France, who led a separate research team, said: “Under the effects we saw from the pesticides, the population size would decline disastrously, and make them even more sensitive to parasites or a lack of food.”

The reason for the huge decline in bee numbers has remained uncertain, but pesticides, the varroa mite and other parasites, and destruction of the flower-rich habitats in which bees feed are believed to be the key reasons. Pesticide manufacturers and the UK government deny a class of the chemicals called neonicotinoids cause significant problems for bees, but Germany, Italy and France have suspended key insecticides over such fears.

A spokesperson from Department for Environment, Food and Rural Affairs (Defra) said the new research did not change the government’s position. “The UK has a robust system for assessing risks from pesticides and all the evidence shows neonicotinoids do not pose an unacceptable risk to honeybees when products are used correctly. However, we will not hesitate to act if presented with any new evidence.” Henry said the new research showed current approval processes for the pesticides are inadequate: “We now have enough data to say authorisation processes must take into account not only the lethal effects, but also the effects of non-lethal doses.”

The pesticides investigated in the new studies – insect neurotoxins called neonicotinoids – are applied to seeds and flow through the plants’ whole system. The environmental advantage of this is it reduces pesticide spraying but chemicals end up in the nectar and pollen on which bees feed. Goulson’s group studied an extremely widely used type called imidacloprid, primarily manufactured by Bayer CropScience, and registered for use on over 140 crops in 120 countries.

Bumblebees were fed the toxin at the same level found in treated rape plants and found that these colonies were about 10% smaller than those not exposed to the insecticide. Most strikingly, the exposed colonies lost almost all of their ability to produce queens, which are the only bee to survive the winter and establish new colonies. “There was a staggering magnitude of effect,” said Goulson. “This is likely to have a substantial population-level impact.”

The French team analysed the effect on honey bees of a new generation neonicotinoid, called thiamethoxam and manufactured by Syngenta. They fitted tiny electronic tags to over 650 bees and monitored their activity around the hive. Those exposed to “commonly encountered” levels of thiamethoxam suffered high mortality, with up to a third of the bees failing to return. “They disappeared in much higher numbers than expected,” said Henry. Previous scientific work has shown insect neurotoxins may cause memory, learning, and navigation problems in bees.

A spokesman for Syngenta said: “Although we take good research very seriously, over the last four years, independent authorities in France have closely monitored the use of Cruiser – the product containing thiamethoxam – on more than 1.9m hectares. When properly used no cases of bee mortality have been recorded.”

Julian Little, spokesman for Bayer Cropscience, criticised Goulson’s study because the bees were exposed to imidacloprid in the labaratory, before being placed outside in a natural field environment to feed. “All studies looking at the interaction of bees and pesticides must be done in a full field situation,” he said. “This study does not demonstrate that current agricultural practices damage bee colonies.”

Goulson dismissed as “nonsense” Little’s suggestion that the doses given to the bees were higher than in reality. Both Bayer and Defra suggested other field studies had shown no harmful effects to bees. Goulson said: “If they have done these studies, where are they? They are not in the public domain and therefore cannot be scrutinised. That raises the question of just how good they are.”

From The Guardian: http://www.guardian.co.uk/environment/2012/mar/29/crop-pesticides-honeybee-decline