WASHINGTON — Two years ago, Steve McDaniel’s bees started dropping like flies.
“This has all the marks of a pesticide kill,” he said, describing the piles of dead bees that appeared outside his hives in Manchester, Maryland, 65 miles north of here. “It’s the only thing that makes sense.”
McDaniel, a master beekeeper, has been safeguarding his honeybee colonies from mites, viruses and other maladies for 35 years. Now he and some other beekeepers blame a class of pesticides called neonicotinoids that have gained widespread use in the past decade and have been linked to a mysterious die-off of bees called Colony Collapse Disorder.
They want the EPA to follow the lead of the European Union in December and ban its use.
Chemical makers Bayer, Syngenta and Dow Chemical say neonicotinoids aren’t to blame for the bee deaths and have stepped up their own lobbying to counter calls for a ban as well as legislation now in Congress. Eliminating the products will do little for bees and force farmers and gardeners to go back to more harmful products, they say.
At stake are billions of dollars in agricultural production. Bees pollinate scores of plants from apricots to zucchini and are responsible for increasing crop values by $15 billion each year, according to the Department of Agriculture. Recent surveys have shown almost a third of bees in an estimated 2.6 million colonies fail to survive the winter dormant season.
More than half the nation’s commercial bees are needed to pollinate one crop: the $4.8 billion annual harvest of almonds, the country’s most lucrative nut. Companies using pollinator- aided crops range from Hershey, maker of Almond Joy candy bars, to Burt’s Bees lip-balm producer Clorox.
Neonicotinoids work by permeating a plant, protecting it throughout the growing season. This eliminates repeated spraying and represents “a revolution in pest control,” said Dave Fischer, an environmental director at Bayer CropScience. “These products are being used in sustainable agriculture and is not causing widespread losses of pollinators.”
The EU in December banned three pesticides for two years, citing studies showing that the neonicotinoids — clothianidin, imidacloprid and thiametoxam — may pose a risk to bees while acknowledging that conclusive proof is elusive. Environmental groups in Canada, including the Sierra Club Canada Foundation, have pushed for tighter regulation of the products there.
Bee deaths reached alarming proportions in 2006 when scientists identified Colony Collapse Disorder, a syndrome of unknown cause marked by disoriented bees failing to find their way back to their hives and dying. Beekeepers suddenly reported losing roughly a third of their colonies — up from 15 percent in previous years.
The cause remains a subject of fierce debate and no effective antidote has been discovered. Suspicion has ranged from the varroa mite, a parasite that has infested U.S. hives since 1987, to viruses and a loss of habitat.
In recent years, research has also linked neonicotinoids to bee mortality. A study released last week by a researcher at Harvard School of Public Health found a link between sub-lethal levels of neonics in winter bee losses. The study found that both exposed and unexposed insects survived other times of year equally well, while pesticide-treated groups fared much worse at the end of the winter, exhibiting symptoms of Colony Collapse Disorder.
This suggests that the chemicals trigger the disorder in bees, possibly by impairing their neurological functions, according to the study.
“We demonstrated again in this study that neonicotinoids are highly likely to be responsible for triggering CCD in honey bee hives that were healthy prior to the arrival of winter,” lead author Chensheng Lu, associate professor of environmental exposure biology, said in a statement.
Bayer dismissed the study, saying the colony failures were prompted in part because bees were fed artificially high levels of pesticides. The study “provides no meaningful information regarding honey bee risk assessment,” the company said in a statement.
The chemicals have been on the market for two decades, though lower-toxicity neonics such as clothianidin, marketed by Bayer as Poncho, emerged a decade ago and opened the door to widespread use in corn and soybeans, the two largest U.S. crops.
Jeff Pettis, who leads the USDA’s bee research laboratory in Beltsville, Maryland, told lawmakers in a congressional subcommittee hearing April 29 that the best action Congress could take to help beekeepers would be to better fund research into varroa, which he called a “modern plague” for bees. He characterized pesticides as a secondary concern.
Still, “exposure to pesticides in the environment may be weakening bee colonies, possibly making them more susceptible to other stresses,” he said.
Tim Tucker, president of the American Beekeeping Federation, called pesticides the No. 1 problem for beekeepers.
“Our loss numbers are unsustainable,” said Tucker, a Niotaze, Kansas, beekeeper who quit traveling to California to pollinate almonds in 2007 because it’s become more profitable to concentrate on building hives he then sells to others who have suffered colony collapse. “We are constantly rebuilding, and it’s not getting any better.”
Tucker and his group have stopped short of supporting an outright ban on neonicotinoids, preferring to find ways to cut back chemical use that would then make bee losses more manageable.
“I don’t know what would replace them” for farm needs, he said. Still, current application “is way overboard,” he said. “I would like to see how we could do the job with the least amount of pesticides possible.”
Bee loss rates have leveled off in recent years, but remain high enough to create seasonal shortages that threaten to raise food prices, according to the USDA.
Rep. Earl Blumenauer, D-Ore., has introduced a bill to ban neonicotinoids The Center for Food Safety, Friends of the Earth and the American Bird Conservancy have all backed a ban, while the American Seed Trade Association, CropLife America and Bayer have all lobbied to discourage one.
Blumenauer called evidence of a pollinator tie “overwhelming” while Sen. Heidi Heitkamp, D-N.D., said habitat loss has been the main factor behind declines in her state, the leading U.S. honey producer.
Supporters of a ban say the pesticide link can’t be denied.
“The weight of the evidence shows this is a problem,” said Lisa Archer, food and technology director for Berkeley, California-based Friends of the Earth, comparing chemical companies to climate-change deniers who insist on standards of proof that can’t be met. “It would be smarter to have fewer pesticides.”
The EPA, which regulates neonicotinoids, has ordered six new studies of the chemicals, and last August issued guidance on pesticide labeling intended to aid users in reducing chemical risk to bees. The agency, which periodically re-evaluates all pesticides, is due to look at neonicotinoids beginning in 2016.
That isn’t soon enough for McDaniel, the Maryland beekeeper, who said continued use of the chemicals may push beekeepers out of business. He attributes the sudden impact on his colonies to suburban development that’s bringing more home gardeners, and their pesticides, to the area.
“People who take good care of their hives can’t protect themselves against this,” he said. Claims that pesticides aren’t hurting his bees are “an outright lie.”
“This stuff is really nasty.”
— With assistance from Jack Kaskey in Houston.