Corn insecticide linked to honeybee die-off

New research has linked springtime die-offs of honeybees with insecticides used to coat corn seeds, according to a study in American Chemical Society’s journal Environmental Science & Technology on March 6, 2012. The finding might be a clue to the cause of the mysterious malady afflicting honeybees called colony collapse disorder. A honeybee that flies through the cloud of poison will die.

Colony collapse disorder, or the mass die-off of honeybees, has stumped researchers up to now.

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The chemicals – called neonicotinoid insecticides – are used to coat corn seeds and are among the most widely used insecticides in the world, popular because they kill insects by paralyzing nerves but have lower toxicity for other animals.

Almost immediately after neonicotinoid insecticides went into wide use in Europe in the late 1990s, beekeepers observed large die-offs of bees that seemed to coincide with mid-March to May corn planting, says the report. Scientists thought this might be due to particles of insecticide made airborne by drilling machines used for planting. These machines forcefully suck in seeds and expel a burst of air containing high concentrations of particles of the insecticide coating. In an effort to make the drilling method safer, the scientists tested different types of insecticide coatings and seeding methods.

How a honeybee is poisoned

But they found that all of the variations in seed coatings and planting methods killed honeybees that flew through the emission cloud of the seeding machine. The authors suggest that future work on this problem should focus on a way to prevent the seeds from fragmenting inside the pneumatic drilling machines.

Bottom line: A study in the March 6, 2012 issue of the American Chemical Society’s journal Environmental Science & Technology links springtime die-offs of honeybees with insecticides used to coat corn seeds. The finding might be a clue to the cause of the mysterious malady called colony collapse disorder.

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