FRESNO -- The health of the nation's honeybees may be improving slightly, but a mysterious combination of ailments is still decimating their colonies, federal officials said Tuesday.
U.S. Department of Agriculture researchers said bee colonies declined by 29 percent between September 2008 and early April, an improvement over the same period in the previous two years, when researchers found that 32 percent and 36 percent of all beekeepers surveyed lost hives.
Honeybees help pollinate many fruits and vegetables, including blueberries, tomatoes, apples and California's bountiful almond crop.
Domestic honeybee stocks have been waning since 2004, when scientists learned of a puzzling illness they called colony collapse disorder, which causes adult bees to inexplicably forsake their broods.
Last winter, only 26 percent of the apiaries surveyed reported that some of their bees died of colony collapse disorder, down from 36 percent in the year before, researchers found.
The disorder has killed off the weakest colonies in recent years, and now pesticide drift and old foes such as the parasitic varroa mite are more likely to be threatening those that survived, said Jerry Hayes, a former president of the Apiary Inspectors of America, whose members helped carry out the survey.
"Whether it's CCD or pesticides, fungicides, or chemicals affecting how the queens respond, I don't know that beekeepers care," said Hayes, chief of the apiary sector of the Florida Department of Agriculture. "The ones who I talk to are just beside themselves. If you are a small-businessperson, how many years of 30 percent losses can you take?"
Regardless of the cause, bees are still dying at rates that could put some keepers out of business, said Jeff Pettis, the USDA's top bee scientist.
The survey included 787 beekeepers who account for 20 percent of the country's approximately 2.3 million commercially managed bee hives. The data -- collected through a spring telephone survey in which researchers polled keepers about how many of their hives survived the fall and winter, when queens go dormant -- is being prepared for submission to a journal.
