What’s The Buzz? Scientists Explore Pesticide Poisoning of Bees

WASHINGTON — Scientists and worried beekeepers agreed Tuesday to explore pesticide poisoning, diseases, parasites and management practices in an effort to find out why billions of honeybees in 25 states have died in the past six months.

Following two days of brainstorming, about 80 bee experts agreed to recommend an urgent research agenda aimed at sorting out the causes of “colony-collapse disorder,” an unusual die-off that became apparent last year.

The conference in Maryland was set up after a House agriculture subcommittee criticized the Department of Agriculture for not responding to the die-off quickly enough.

“We should have been doing this two months ago,” said Troy Fore, of Jessup, Ga., executive secretary of the American Beekeeping Federation.

For Michigan beekeepers, an answer can’t come too soon.

Beekeepers here are among those afflicted by the unexplained disappearance of entire colonies of bees, said David Anthony, president of the Michigan Beekeepers Association. Commercial beekeepers lost as many as 80 percent of the bees they transported south over the winter.

The colony-collapse phenomenon occurs when worker bees leave the hive and don’t return. Queens and bee larvae remain inside the hive until they die.

Colony-collapse phenomenon resembles many of the ways bees have always died, scientists agreed, but there’s one notable exception: The empty hive is shunned by other bees and insect scavengers.

Besides the honey they produce, bees provide billions of dollars worth of pollination services each year for American agriculture. A National Academy of Science committee warned a few months ago that their role in that area has been woefully neglected.

In southwestern Michigan, bees are used to pollinate cherries, apples and blueberries, and vegetable crops such as cucumbers.

Scientists at the conference had many hypotheses for the die-off but no answers.

They theorized that the disorder could have a tangle of contributing factors — each benign on its own but combining to create a deadly threat.

A spreading infestation of mites that invaded the U.S. bee industry in the 1980s could have weakened the insects and left them susceptible to infections they have resisted for ages.

Pesticides, especially a relatively new class of chemicals called neonicotinoids, could have sublethal effects that do the same thing. These chemicals are now America’s most widely used pesticides — applied to crops, at homes and on golf courses, for example — and they act by disrupting the insects’ nervous systems. This might be related to the failure of worker bees to return to hives, as if they have become disoriented.

“It’s too strong a coincidence to ignore,” said Maryann Frazier, a Pennsylvania State University entomologist.

She said samples have been sent to a U.S. Environmental Protection Agency lab in North Carolina to be analyzed for more than 200 pesticides.

Still another theory is that mites could be spreading a disease-causing virus among bees.

Bee-management practices also must be investigated, scientists said.

Jerry Hayes, a Florida Department of Agriculture entomologist, said bees are given a variety of antibiotics to ward off infections, and this may be interfering with natural bacteria in their guts that help ferment pollen to produce a hive food.

One experiment in countering the effects of the disorder involves treating hives with acids or irradiating them.

Kalamazoo Gazette staff writer Rosemary Parker contributed to this story.