Fri Mar 16, 2012, 02:06 PM
JDPriestly (37,727 posts)
Do neonicotinides cause bee decline?
What was killing all those honeybees in recent years? New research shows a link between an increase in the death of bees and insecticides, specifically the chemicals used to coat corn seeds.
The study, titled "Assessment of the Environmental Exposure of Honeybees to Particulate Matter Containing Neonicotinoid Insecticides Coming from Corn Coated Seeds," was published in the American Chemical Society's Environmental Science & Technology journal, and provides insight into colony collapse disorder.
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According to the new study, neonicotinoid insecticides "are among the most widely used in the world, popular because they kill insects by paralyzing nerves but have lower toxicity for other animals."
Beekeepers immediately observed an increase in die-offs right around the time of corn planting using this particular kind of insecticide.
Pneumatic drilling machines suck the seeds in and spray them with the insecticide to create a coating before they are planted in the ground. Researchers suspected the mass die-offs could have been caused by the particles of insecticide that were released into the air by the machines when the chemicals are sprayed.
Pesticide Toxicity Profile: Neonicotinoid Pesticides1
Frederick M. Fishel2]
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The mode of action of neonicotinoid pesticides is modeled after the natural insecticide, nicotine. They act on the central nervous system of insects. Their action causes excitation of the nerves and eventual paralysis which leads to death. Because they bind at a specific site (the postsynaptic nicotinic acetylcholine receptor), they are not cross-resistant to the carbamate, organophosphate, or synthetic pyrethroid insecticides, which was an impetus for their development. As a group, they are effective against sucking insects, but also chewing insects such as beetles and some Lepidoptera, particularly cutworms. All neonicotinoid products are classified as general use and have been registered under EPA's Conventional Reduced Risk Program due to their favorable toxicological profiles.
This could explain why I have so many bees here in Southern California. We don't grow corn for commercial sale much around here. Maybe some, but not much.
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Response to JDPriestly (Original post)
Fri Mar 16, 2012, 04:51 PM
Denninmi (5,558 posts)
1. I'm sure they probably do.
But I don't think "colony collapse" has one discrete cause. More likely a combination of things. Frankly, mite pressure is still strong. I took a beekeeping (for credit, and graded) class at Michigan State in the 1980s. Mites were known but hadn't arrived in Michigan yet at the time. Believe me, I see an overall decline in the vigor of colonies now. And, despite everything I throw at them, from Apistan to menthol to whatever, I can't eliminate mites, just keep them suppressed to tolerable levels.
Response to JDPriestly (Reply #2)
Mon Mar 19, 2012, 06:43 AM
Denninmi (5,558 posts)
No farming anywhere around here now, all suburban sprawl.
I think they would be just as likely to encounter imidacloprid (Merit) from treated lawns, since its the main active ingredient in retail lawn grub control products, and widely used by golf courses, etc. Probably the lawn services, too.