Science in Society Archive

Emergency Pesticide Ban for Saving the Honeybee

Prof. Joe Cummins’ warning against neonicotinoid pesticides in the killing of honeybees was dramatically confirmed, resulting in swift action on the part of the German Government. Dr. Mae-Wan Ho

Germany’s emergency ban

The German Federal Office of Consumer Protection and Food Safety (BVL) suspended the registration of eight neonicotinoid pesticide seed treatment products used in oilseed rape and sweetcorn. a few weeks after honeybee keepers in the southern state of Baden Württemberg reported a wave of honeybee deaths linked to one of the pesticides, clothianidin [1, 2]. Prof. Joe Cummins had warned specifically against this class of new pesticides [3] (Requiem for the Honeybee, SiS 34), widely used in dressing seeds and in sprays, and “highly toxic to insects including bees at very low concentrations.”  His contribution to ISIS’ Briefing in the European Parliament in June 2007 [4] (Scientists and MEPs for a GM free Europe, SiS 35) drew attention to the danger of sub-lethal doses of neonicotinoids and Bt biopesticides in GM crops, which could act synergistically with pathogenic fungi in causing Colony Collapse Disorder in the honeybee, and resulted in a question to the European Commission by German MEP Hiltrud Breyer [5] (Emergency Motion on Protecting the Honeybee, SiS 35), shortly after she has submitted an emergency motion to ban the neonicotinoids.

Unequivocal evidence of pesticide poisoning

Walter Haefeker, president of the European Professional Beekeepers Association, reporting to Chemical and Engineering News said [1], “Beekeepers in the region started finding piles of dead bees at the entrance of hives in early May, right around the time corn seeding takes place.”

It's a real bee emergency,” said Manfred Hederer, president of the German Professional Beekeepers' Association told The Guardian [2], “50-60 percent of the bees have died on average and some beekeepers have lost all their hives.”

The incriminating evidence was so convincing that a press release from the Julius Kuehn Institute (JKI), the German federal agricultural research agency, stated: “It can unequivocally be concluded that a poisoning of the bees is due to the rub-off of the pesticide ingredient clothianidin from the corn seeds.”

Tests on dead bees showed that 99 percent had a build-up of clothianidin.(sold in Europe under the trade name Poncho) produced by Bayer CropScience,  approved for use in Germany in 2004, and with some restrictions in the US in 2003.

The pesticide was applied to the seeds in advance of being planted or sprayed while in the field. The company blamed an application error by the seed company which failed to use a substance that glues the pesticide to the seed, resulting in the chemical getting into the air. Bayer spokesman Dr Julian Little told the BBC Farming Today that misapplication is highly unusual. It transpired that this year’s corn seed in Baden Württemberg was coated with a double dose to counteract a corn beetle infestation [2]. Unusual circumstances yes, but the lethal effect of the pesticides has been suspected for a long time.            

Beekeepers had pointed the finger for a long time

According to the report in The Guardian [1], a group of beekeepers from North Dakota in the United States is taking Bayer CropScience to court after losing thousands of honeybee colonies in 1995, during a period when oilseed rape in the area was treated with imidacloprid. A third of honeybees were killed by what has since been dubbed colony collapse disorder.

Imidacloprid is Bayer’s best-selling pesticide sold under the name Gaucho in France, but has been banned as a seed dressing for sunflowers in that country since 1999, when a third of French honeybees died following its widespread use; the ban on its use in sweetcorn was imposed five years later. A few months ago, the company’s application for clothianidin was rejected by French authorities.

Bayer has always maintained that imidacloprid is safe for bees if correctly applied. “Extensive internal and international scientific studies have confirmed that Gaucho does not present a hazard to bees,” said Utz Klages, a spokesman for Bayer CropScience. Last year,

Germany’s Green MEP, Hiltrud Breyer tabled an emergency motion calling for this family of pesticides to be banned across Europe while their role in killing honeybees is thoroughly investigated. Her action follows calls for a ban from beekeeping associations and environmental organisations across Europe.

As Cummins pointed out [3], these pesticides are nerve poisons and inhibit the brain enzyme acetylcholine esterase. Sub-lethal levels of the pesticide which fails to kill the bee will nevertheless impair its ability to return to the hive. Furthermore, these and other pesticides also impair the bee’s immune system, leaving it much more susceptible to attacks by parasitic fungi and other disease agents [6, 7] (Parasitic Fungi and Pesticides Act Synergistically to Kill Honeybees? SiS 35, Mystery of Disappearing Honeybees, SiS 34).

Article first published 09/06/08


  1. “Pesticides: Germany bans chemicals linked to honeybee devastation”, Allison Benjamin,, Friday May 23 2008
  2. “Honeybee Loss”, Sarah Everts, C&EN, Chemical and Engineering News 21 May 2008.
  3. Cummins J. Requiem for the honeybee. Science in Society 34, 37-38, 2007.
  4. Burcher S. and Ho MW. Scientists and MEPs for a GM free Europe. Science in Society 35, 20-25, 2007.
  5. Hiltrud B. Collapse of honeybee colonies worldwide. Written Question to the European Commission Science in Society 35, 39 2007.
  6. Cummins J. Parasitic fungi and pesticides act synergistically to kill honeybees?  Science in Society 35, 38 2007.
  7. Ho MW and Cummins J. Mystery of disappearing honeybees. Science in Society 34, 35-36. 2007.

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