Imidacloprid represents the new generation of neurotoxic insecticides, which exhibit more selective toxicity for insects relative to mammals. Since being introduced in the insecticide market in 1992, the use of imidacloprid has increased yearly. It ranked as one of the top selling pesticides in the world in 2001-2002. For the most part, it is replacing the acetylcholinesterase inhibitors, the organophosphorus compounds and methylcarbamates. Many organophosphates are potent neurotoxins, functioning by inhibiting the action of acetylcholinesterase (AChE) in nerve cells. They are one of the most common causes of poisoning worldwide, and are frequently intentionally used in suicides in agricultural areas. Their toxicity is not limited to the acute phase, however, and chronic effects have long been noted. Neurotransmitters such as acetylcholine (which is affected by organophosphate pesticides) are profoundly important in the brain's development, and many OPs have neurotoxic effects on developing organisms even from low levels of exposure. examples: * malathion * diazinon * phosmet (Imidan(R)) * chlorpyrifos (Lorsban(R)) Some of the organophosphates are very toxic. Parathion, for example, is 30 times more toxic than DDT. Each year organophosphates poison thousands of humans throughout the world, causing hundreds of deaths. Medical personnel caring for poisoning victims are also at risk. They may be seriously poisoned by the excretions of, and even the vapors emanating from, their patients. Carbamate insecticides are also inhibitors of acetylcholinesterase, but their action is reversible. Some examples: * carbaryl (Sevin(R)) * aldicarb (Temik(R)) * methomyl (Lannate(R)) Features: * These compounds are rapidly detoxified and excreted so their risk to warm-blooded animals is less than the other agents we have looked at. * They are degraded rapidly in the environment so persistence is not a problem. * They are, however, a danger to many useful insects, especially honeybees. -- Peter L. Borst Danby, NY USA 42.35, -76.50 http://picasaweb.google.com/peterlborst ****************************************************** * Full guidelines for BEE-L posting are at: * * http://www.honeybeeworld.com/bee-l/guidelines.htm * ******************************************************