Scientists in recent years have attempted to identify the factors behind the increasing numbers of honeybee deaths in North America and Europe -- and new research has found the use of a specific class of insecticides in cornfields may be responsible. 

The American Chemical Society recently published a study titled Assessment of the Environmental Exposure of Honeybees to Particulate Matter Containing Neonicotinoid Insecticides Coming from Corn Coated Seeds in its Environmental Science & Technology journal. The study explores the impact of industrial pesticides on honeybee colonies.

In recent years, scientists have observed a phenomenon known as colony collapse disorder (CCD), which is characterized by worker bees mysteriously disappearing from a colony, leading to its collapse. While many factors have been proposed -- from insect viruses to cell-phone radiation -- and they may all play a part, the new study shows a strong correlation between CCD and the use of neonicotinoid insecticides.

According to an ABC News report on the 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.

These insecticides are designed to target crop-eating pests, and are applied to corn seeds before planting. However, the study found the insecticides inadvertently affect honeybees when the seed-drilling machines emit particles into the air.

Experimental results show that the environmental release of particles containing neonicotinoids can produce high exposure levels for bees, with lethal effects compatible with colony losses phenomena observed by beekeepers, according to the article.

Industrial corn production has increased in recent years with its use as both a food crop and in the production of ethanol, leading to the application of more insecticides. As pests adapt and develop stronger resistances to the insecticides, more potent ones have to be developed. The effect has devastated honeybee populations.

Insecticides are a controversial but integral part of industrial agriculture, as crops are particularly vulnerable to pests. This is a result of being grown in isolation with artificial inputs, as opposed to more traditional and organic methods, which allow crops to naturally adapt resistance to pests and pathogens.

The researchers are exploring ways to make seed-drilling machines safer for bees, ABC News reported, but tackling the use of insecticides in industrial agriculture is a much more complicated task.

Honeybees, themselves, are an important part of agriculture, as they are responsible for the pollination of many crops, an estimated one-third of which is consumed by humans.