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Laboratory bioassays conducted to determine the contact honey bee toxicity of commercial neonicotinoid insecticides showed that the nitro-substituted compounds were the most toxic to the honey bee with LD50 values of 18 ng/bee for imidacloprid and 30 ng for thiamethoxam. The cyano-substituted neonicotinoids exhibited a much lower toxicity with LD50 values for acetamiprid and thiacloprid of 7.1 and 14.6 µg/bee, respectively. However, piperonyl butoxide and propiconazole increased honey bee toxicity of acetamiprid 6.0- and 105-fold and thiacloprid 154- and 559-fold, respectively, but had a minimal effect on imidacloprid (1.70 and 1.52-fold, respectively). A broad survey of pesticide residues conducted on samples from North American apiaries during the 2007–08 growing seasons revealed the presence of 121 different pesticides and metabolites within wax, pollen, bee and associated hive samples, including acetamiprid, thiacloprid, imidacloprid, thiamethoxam, piperonyl butoxide and propiconazole. Thus, under practical circumstances, acetamiprid and thiacloprid can be as toxic to honey bees as imidacloprid and thiamethoxam.

Le premier novembre paraîtra le livre du toxicologue hollandais Dr Henk Tennekes, „A disaster in the making“ qui traite des causes de la mort des oiseaux et des abeilles dans toute l’Europe. Le Dr Tennekes y montre que le recul considérable de nombreuses populations avicoles est lié à la décimation que les pesticides infligent aux insectes. Les populations de coléoptères, mouches, papillons et teignes, dont se nourrissent les oiseaux, ont reculé principalement en raison de l’emploi des néonicotinoïdes. Le premier producteur de néonicotinoïdes, parmi lesquels les molécules actives imidaclopride, thiaclopride et clothianidine est la firme Bayer Cropscience. L’imidaclopride passe pour le pesticide le plus vendu dans le monde, et la société Bayer en a retiré pour la seule année dernière 606 millions d’euros. La clothianidine, également produite par Bayer, avait provoqué il y a deux ans la mort à grande échelle des abeilles d’Allemagne du Sud. Le Dr Tennekes exige une interdiction immédiate de ces traitements: « Les risques qu’entraînent des pesticides tels que l’imidaclopride et le thiaclopride sont énormément sous-estimés. Une catastrophe environnementale nous menace et la firme Bayer en est responsable. Il faut à mon avis interdire de toute urgence les néonicotinoïdes si l’on ne veut pas voir les abeilles et les oiseaux continuer à s’éteindre. »

Widespread use of insecticides is affecting bee populations but also causing decline in numbers of birds, butterflies and moths, warns Dutch toxicologist. A new book is blaming the significant decline of bird and bee numbers across Europe on the use of certain pesticides in agriculture. In The Systemic Insecticides: A Disaster in the Making, toxicologist Dr Henk Tennekes suggests that dangerous insecticides known as neonicotinoids are seriously affecting bird and insect life, and their continued use could result in an ‘environmental catastrophe’.

Could we be facing a future without birds? Our reliance on pesticides has cut a swathe through their numbers. We must act now, argues Kate Ravilious. It is nearly 50 years since Rachel Carson wrote Silent Spring, the book that warned of environmental damage the pesticide DDT was causing. Today, DDT use is banned except in exceptional circumstances, yet we still don't seem to have taken on board Carson's fundamental message. According to Henk Tennekes, a researcher at the Experimental Toxicology Services in Zutphen, the Netherlands, the threat of DDT has been superseded by a relatively new class of insecticide, known as the neonicotinoids. In his book The Systemic Insecticides: A Disaster in the Making, published this month, Tennekes draws all the evidence together, to make the case that neonicotinoids are causing a catastrophe in the insect world, which is having a knock-on effect for many of our birds.

Afgelopen woensdag (3 november 2010) was er een rondetafelgesprek over gif - of gewasbescherming zoals de sector het zelf graag noemt - in de Tweede Kamer. Dr. Henk Tennekes, die onderzoek doet naar de relatie tussen neonicotinoiden – een heel giftige insecticide - en bijensterfte, was daar ook aanwezig als deskundige. Dr. Tennekes is lang bezig geweest met onderzoek naar kanker. Hij vertelde mij dat hij betrokken raakte bij het onderzoek naar bijensterfte, toen hij ontdekte dat insecticiden zoals imidacloprid op een vergelijkbare manier werken als kankerverwekkende stoffen. Toen hij zich realiseerde wat dit betekent voor het milieu en de biodiversiteit, heeft hij besloten hier werk van te maken. Om zijn zorgen over de effecten van neonicotinoiden met een wijder publiek te delen, heeft Dr. Tennekes ook een boek geschreven over dit onderwerp: The systemic insecticides: a disaster in the making. Voorafgaand aan het rondetafelgesprek bood Henk mij zijn nieuwe boek aan. Hij wilde mij daarmee bedanken voor het feit dat ik al in 2007 Kamervragen heb gesteld over dit onderwerp.

Am 1. November 2010 erschien das Buch „A disaster in the making“ des holländischen Toxikologen Dr. Henk Tennekes über die Ursachen des europaweiten Bienen- und Vogelsterbens. Das Buch wird mit ganzseitigen Bildern des Künstlers Ami-Bernard Zillweger illustriert. Dr. Tennekes legt darin dar, dass der drastische Rückgang zahlreicher Vogelpopulationen, unter anderem Spatzen Bachstelzen, Stare, Kiebitze oder Feldlerchen, mit der Dezimierung von Insekten in Zusammenhang steht. Käfer, Fliegen, Schmetterlinge und Motten, die den Vögeln als Nahrung, werden vor allem durch die Anwendung von Pestiziden, sogenannten Neonicotinoiden, reduziert.

A 72-page 2010 publication raises new and troubling questions about a widely used insecticide's potential for harm to bees, beneficial insects, and bird populations. Using imidacloprid as an example, Dutch toxicologist Dr. Henk Tennekes reports on the hazards of imidacloprid to insects and birds. Imidacloprid is a neonicotinoid chemical, and has systemic action in plants. Other European researchers have linked this insecticide to significant risks for honey bee populations, including possible links to Colony Collapse Disorder.

Dr. Tennekes' findings indicate that imidacloprid (and possibly other neonicotinoid-type insecticides) can bind irreversibly to critical receptors in an insect's nervous system. If these receptors are permanently blocked, the insecticide would not follow a typical dose-response curve. He provides evidence that long term low level to imidacloprid exposure can lead to neurological problems and eventual death of insects.

Studies have shown imidacloprid to be highly persistent in the environment (RCC Compendium of Pesticide Information). In his book, Tennekes presents data showing that imidacloprid has contaminated most of the waterways in the Netherlands.

Systemic activity in plants combined with long-term persistence in the environment and toxicity at low concentrations can be a dangerous combination. Many vulnerable species over large areas could be exposed to this insecticide on land, in surface water following runoff from treated areas and in groundwater due to its potential for leaching through certain soil types.

Several previous studies have shown that imidacloprid is highly toxic to various forms of wildlife, including honey bees, certain beneficial insects, upland game birds, and crustaceans

Tennekes further suggests that imidacloprid has led to a general decline in the insect populations in the Netherlands, and this lack of food in turn has been responsible for declines in bird populations.