Courtesy of the American Chemical Society
New research has linked springtime die-offs of much-needed honeybees — part of a mysterious malady called colony collapse disorder — with a technology for planting insecticide-coated corn.
The research appears on the eve of spring planting seasons in some parts of Europe where farmers use the technology and widespread honeybees deaths have occurred. The study appears in the journal Environmental Science & Technology, published by the American Chemical Society.
The researchers, Andrea Tapparo of the University of Padova in Italy and colleagues, said seeds coated with so-called neonicotinoid insecticides went into wide use in Europe in the late 1990s. The pesticides are among the most widely used in the world, popular because they kill insects by paralyzing nerves but have lower toxicity for other animals.
But almost immediately, beekeepers noticed large die-offs of bees that seemed to coincide with mid-March to May corn planting, the investigators said. Scientists thought this might be due to particles of insecticide thrown aloft by drilling machines used for planting. These machines forcefully suck seeds in and expel a burst of air containing high concentrations of particles of the insecticide coating, according to the researchers.
In an effort to make the pneumatic drilling method safer, the scientists tested different types of insecticide coatings and seeding methods. But they found that all variations in seed coatings and planting methods killed honeybees that flew through the seeding machine’s emission cloud. One machine modified with a deflector to send the insecticide-laced air downwards still caused the death of more than 200 bees foraging in the field.
The authors suggest that future work on the problem should focus on a way to prevent the seeds from fragmenting inside the pneumatic drilling machines.