Entomologist finds four-year consistency in losses 'mildly encouraging'
By TIM HEARDEN
PALO CEDRO, Calif. -- The national die-off rate for honeybee colonies from all causes was 30 percent last winter, according to an annual survey by the USDA and the Apiary Inspectors of America.
That's down slightly from the 32 percent of bees lost in the winter of 2009-10, and it's roughly consistent with losses in each of the past four winters, the two agencies state.
Beekeepers who reported colony losses with no dead bees present -- a key symptom of colony collapse disorder -- suffered colony losses averaging 61 percent, the survey found.
The fact that higher percentages of bees aren't dying each year is "mildly encouraging," said Jeff Pettis, an entomologist for USDA's Agricultural Research Service who helped conduct the study.
The problem doesn't appear to be getting worse, although continued losses of this size put tremendous pressure on the viability of commercial beekeeping, Pettis acknowledged in a USDA news release announcing the survey results.
However, for many beekeepers whose colonies have suffered steep losses year after year, the crisis is escalating, said Shannon Wooten, a Palo Cedro, Calif., queen bee breeder.
"If we're not gaining, then we're losing," said Wooten, who lost 2,000 of his 5,000 hives this past winter. "We still don't know what the problem is, we don't know what the cause is. We don't know what to do. If I knew what to do I would do it."
Researchers have yet to nail down the cause of colony collapse disorder, which has affected hives throughout North America and is marked by rampant bee disappearances. The presence of chemicals has been mentioned as one potential cause, as have tiny mites attaching themselves to bees.
Bees pollinate some 100 crops in California, including about 70,000 acres of almonds, mostly in the Sacramento and San Joaquin valleys, according to University of California statistics. The value of California crops pollinated by bees is $6.1 billion, UC-Davis apiculturist Eric Mussen has said.
The USDA and AIA surveyed 5,572 beekeepers nationwide, who manage more than 15 percent of the country's estimated 2.68 million colonies.
Among the survey's findings:
* The average colony loss for an individual beekeeper's operation in 2010-2011 was 38.4 percent, down from a 42.2 percent average loss the previous winter.
* Sixty-one percent of responding beekeepers reported losses greater than 13 percent -- the level they felt would be economically sustainable.
* Among surveyed beekeepers who lost colonies, 31 percent reported that they noticed the losses without finding dead bees inside -- a symptom that defines colony collapse disorder. The survey didn't differentiate collapse-related losses from other causes.
Winter honeybee losses survey: http://www.extension.org/pages/58013/honey-bee-winter-loss-survey
Colony collapse disorder information: http://www.ars.usda.gov/News/docs.htm?docid=15572