OREGON STATE UNIVERSITY

Honeybee “Colony Collapse Disorder” an Overstated Crisis

07/12/2007

CORVALLIS, Ore. – The “colony collapse disorder” that has alarmed beekeepers and agricultural experts all over the United States is, in all likelihood, a normal variation on problems already known to plague North American honeybees, one expert says. It is not a new and mysterious syndrome.

The cause of unusual levels of bee colony die-offs at specific locations probably relates to local weather issues, bee colony management, pesticide effectiveness, or locally severe concerns with known bee pests, said Michael Burgett, a professor emeritus of entomology at Oregon State University.

Looked at in a broader geographical and historical concept, Burgett said, the existing situation is neither unprecedented nor particularly severe, and certainly not a cause for repeated claims that American agriculture is facing a crisis.

Burgett is one of the world’s leading experts on honeybees. He has done research on them for decades in many locations including their ancestral homes in Asia, Africa and Europe, and was the first scientist in the world to warn 25 years ago of the oncoming plague of tracheal and varroa mites that now are a major threat to U.S. honeybees.

The self-professed old-timer said he is unconvinced that the new problems are, in fact, anything new.

“Calling something a new syndrome or disorder makes for good headlines, but it’s probably not true,” Burgett said. “This field is full of rumor and innuendo, but I haven’t seen any verified statistics or data that would persuade me this is anything but a variation on existing problems. It’s almost certainly something we can address with research, better beekeeper education and colony management.”

In recent months, numerous stories have filled the news with alarming stories of bee colony die-offs, an estimate of 25 percent losses in the nation’s honeybee population, billion dollar crop loss concerns, and other issues.

Some documented losses have clearly been severe, Burgett noted. But in a larger context, they aren’t all that unusual, compared to the last couple decades since parasitic mites spread across the country.

“Some losses have clearly been related to unusually severe winter weather in certain locations, especially in the East,” Burgett said. “And I think there may be some other issues we’re dealing with, mainly variations on known problems that we can address with research and bee colony management. But the losses overall are just slightly higher than normal.”

A regular Pacific Northwest survey of winter bee colony losses was begun in the late 1980s following the invasion of tracheal and varroa mites, Burgett said, and it shows 22 percent average colony losses; the 1998 figure was 27 percent for commercial bee colonies. Some experts are now calling the national losses of 25 percent a “colony collapse disorder,” when on a broader basis those losses are often typical.

A leading suspect for any increased problem, Burgett said, is growing resistance to the pesticides used to control tracheal and varroa mites, and also the increasing use of “softer,” less toxic pesticides that have a lighter environmental touch. They can be effective, but only if used by highly knowledgeable beekeepers in a fairly sophisticated management program.

“When the tracheal and varroa mites first arrived in the 1980s, there were huge losses early on, and the first thing we saw was a lot of marginal operators, who didn’t really know what they were doing, go out of business,” Burgett said.

Other possible concerns, Burgett said, include rising levels of stress from some over-worked bee colonies being moved too often, sometimes to crops that don’t give them adequate nutrition. There’s a theory about pesticide buildup in beeswax that may have some validity, he said, and deserves further research. And a new pathogen called “Nosema ceranae” has been found in a few U.S. honeybees, which might raise some concerns.

The best approach to the issue, Burgett said, is continued research programs and effective Extension outreach to beekeepers and farmers, to make sure they learn the latest techniques needed to keep colonies healthy.

The world of U.S. beekeepers, Burgett said, changed permanently with the arrival two decades ago of two types of parasitic mites that can impact the health of bee colonies or lead to their death. The mites pose an ongoing challenge to commercial beekeepers and are slowly wiping out wild honeybee colonies all over North America.

Some of the reported evidence of colony collapse disorder, Burgett said, such as bee hives with lots of honey but no bees, are in fact the most common symptom of a severe varroa mite infection.

“In the late 1970s we had another scare similar to this, they called it ‘disappearing disease’ at the time,” Burgett said. “But we never found a specific cause for it, we continued to improve our bee management programs, and ‘disappearing disease’ disappeared.”

In the Pacific Northwest, Burgett said, aggressive programs of farmer and beekeeper education have been implemented through many years of university Extension programs, trade journals and other approaches; coincidentally, there is no current problem in the Northwest with “colony loss syndrome.” Winter colony losses this past year were about normal.

“I’m not suggesting this is much ado about nothing,” Burgett said. “But it’s pretty close. Higher levels of colony loss in specific places are probably the result of various causes that can be identified and dealt with. It’s always good to see some funding for bee research and to keep that industry healthy, because it’s important. But the sky is not falling on American agriculture.”