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Imidacloprid is a nicotine-derived systemic insecticide, belonging to a group of pesticides called neonicotinoids. Although it is off patent, the primary producer of imidacloprid is the German chemical firm Bayer CropScience. The trade names for imidacloprid include Gaucho, Admire, Merit, Advantage, Confidor, Provado, and Winner. Imidacloprid is a neurotoxin that is selectively toxic to insects relative to vertebrates and most non-insect invertebrates.〔http://www.fs.fed.us/foresthealth/pesticide/pdfs/122805_Imidacloprid.pdf〕 It acts as an agonist on the postsynaptic nicotinic acetylcholine receptors of motor neurones in insects. This interaction results in convulsions, paralysis, and eventually death of the poisoned insect. It is effective on contact and via stomach action.〔(【引用サイトリンク】title=Pesticide Information Profiles: Imidacloprid )〕 Because imidacloprid binds much more strongly to insect neuron receptors than to mammal neuron receptors, this insecticide is selectively more toxic to insects than mammals. As a systemic pesticide, imidacloprid translocates or moves readily in the xylem of plants from the soil into the leaves, fruit, flowers, pollen, nectar, and guttation fluid of plants. Bees may be exposed to imidacloprid when they feed on the nectar, pollen, and guttation fluid of imidacloprid-treated plants. Experts believe that imidacloprid is one of many possible causes of bee decline and the recent bee malady termed colony collapse disorder (CCD). In 2011, according to the United States Department of Agriculture, no single factor alone is responsible for the malady, however honey bees are thought to possibly be affected by neonicotinoid chemicals existing as residues in the nectar and pollen which bees forage on. The scientists studying CCD have tested samples of pollen and have indicated findings of a broad range of substances, including insecticides, fungicides, and herbicides. They note that while the doses taken up by bees are not lethal, they are concerned about possible chronic problems caused by long-term exposure. In January 2013, the European Food Safety Authority stated that neonicotinoids pose an unacceptably high risk to bees, and that the industry-sponsored science upon which regulatory agencies' claims of safety have relied may be flawed, concluding that, "A high acute risk to honey bees was identified from exposure via dust drift for the seed treatment uses in maize, oilseed rape and cereals. A high acute risk was also identified from exposure via residues in nectar and/or pollen."〔European Food Safety Authority (16 January 2013) ("Conclusion on the peer review of the pesticide risk assessment for bees for the active substance clothianidin" ) ''EFSA Journal'' 11(1):3066.〕 An author of a ''Science'' study prompting the EESA review suggested that industry science pertaining to neonicotinoids may have been deliberately deceptive, and the UK Parliament has asked manufacturer Bayer Cropscience to explain discrepancies in evidence they have submitted to an investigation.〔Damian Carrington (16 January 2013) ("Insecticide 'unacceptable' danger to bees, report finds" ) ''The Guardian''〕 April 2013 the EU decided to restrict thiamethoxam and clothianidin along with imidacloprid.〔(''EU to Restrict 'Bee-Harming' Pesticides'' ) April 29, 2013 Wall Street Journal〕 ==History== Imidacloprid was first registered in the United Kingdom in 1993 and in the United States and France in 1994.〔(Pesticide Action Network. Imidacloprid )〕 In the mid to late 1990s, French beekeepers reported a significant loss of bees, which they attributed to the use of imidacloprid. In 1999, the French Minister of Agriculture suspended the use of imidacloprid on sunflower seeds and appointed a team of expert scientists to examine the impact of imidacloprid on bees. In 2003, this panel, referred to as the Comité Scientifique et Technique (CST, or Scientific and Technical Committee) issued a 108-page report, which concluded that imidacloprid poses a significant risk to bees. In 2004, the French Minister of Agriculture suspended the use of imidacloprid as a seed treatment for maize (corn). Despite these bans, colony collapse disorder still is occurring. Like most insecticides, imidacloprid is highly toxic to bees, with a contact acute LD50 = 0.078μg a.i./bee and an acute oral LD50 = 0.0039μg a.i./bee. Imidacloprid was first widely used in the United States in 1996 as it replaced 3 broad classes of insecticides. In 2006, U.S. commercial migratory beekeepers reported sharp declines in their honey bee colonies. This has happened in the past; however, unlike previous losses, adult bees were abandoning their hives. Scientists named this phenomenon colony collapse disorder (CCD). Reports show that beekeepers in most states have been affected by CCD.〔 Although no single factor has been identified as causing CCD, the United States Department of Agriculture (USDA), in their progress report on CCD, stated that CCD may be "a syndrome caused by many different factors, working in combination or synergistically." In a British parliamentary inquiry in 2012, the Environmental Audit Committee accused European regulators of ignoring evidence of imidacloprid risk to bees. The committee said that imidacloprid data available in the regulators' own assessment report shows "unequivocally that imidacloprid breaks down very slowly in soil, so that concentrations increase significantly year after year with repeated use, accumulating to concentrations very likely to cause mass mortality in most soil-dwelling animal life." The committee submitted a lengthy list of failings in current regulations including concerns that current regulations were set up for pesticide sprays, not systemic chemicals like imidacloprid that is used to treat seeds. They also expressed concern that only effects on honeybees have been considered despite the fact that 90% of pollination is carried out by different species, such as bumblebees, butterflies, moths and other insects. The environment minister responded saying that he is presently "...satisfied that the that (regulatory system ) is working properly." 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「Imidacloprid effects on bees」の詳細全文を読む スポンサード リンク
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