California almond growers have their orchards pollinated by bees, some of which are trucked across the country afterward for work on the East Coast. The trip could be a factor as bee populations decline yearly. Photo Credit: U.s. Department Of Agriculture

By Adrian Higgins
Monday, March 15, 2010

…More than three years after beekeepers starting seeing the sudden disappearance of hive populations, scientists have yet to find the cause -- let alone the fix -- for a condition called colony collapse disorder (CCD). Meanwhile, the commercial beekeeping industry is struggling to provide pollination services to the nations' farmers. One-third of food crops rely on insect pollination.

A recently published survey suggests that hive losses have stabilized at around 30 percent a year, but that high figure is based on last winter's data. Anecdotally, the losses have climbed this winter, although a formal tally won't occur until the spring.

"I am very concerned about this year based on what we have seen in California and other parts" of the United States, said Jeffery S. Pettis, research leader for the Agricultural Research Service's honey bee laboratory in Beltsville. He has visited the almond farms of California three times this winter to assess losses. The state's growers produce 80 percent of the world's almond crop and require 1.5 million of the nation's estimated annual peak of 2.5 million managed hives. In the halcyon days after World War II, there were more than 5 million managed hives in the United States, and countless feral honeybee colonies that are now gone.

Hackenberg said he and other major commercial beekeepers have seen "50 percent or better" losses since late fall and in the winter, when bees typically are clustered in a warm and fuzzy ball within the hive. "We started seeing losses in late October, early November -- and they just kept going through the middle of January," he said. Some of the losses will be made up by beekeepers splitting one strong hive into two weaker ones.

Eighty percent of his afflicted hives showed signs of CCD, Hackenberg said. With the condition, foraging worker bees don't return to a hive even if a full brood is waiting to hatch. One theory is that the foragers, knowing they are sick, fly off to die rather than compromise the hive.

Scientists at first figured that they would identify a single virus or pest responsible for the collapse after the phenomenon surfaced in fall 2006, and an early suspect was a bloodsucking parasite called the Varroa mite. If bees were the size of humans, said Jerry Hayes, of the Florida Department of Agriculture, the mite would be as large as a rat. Another was a pathogen named Israeli acute paralysis virus, which showed up in collapsed colonies.

After three years of research, scientists think the cause is not a single factor but a cocktail of maladies that together weaken and sicken the bees. "We know CCD bees get all the pathogens causing the symptoms; it doesn't leave answered what's the underlying cause," said Dennis van Engelsdorp, Pennsylvania's acting state apiarist.

Environmental stress, including pesticides and the strain of being trucked across time zones and climates, may also be a factor. Poor nutrition may also contribute, a diet of corn syrup or the nutritionally inferior nectar or pollen of crops such as cranberry, cucumbers or melons. …

Bees are busier than ever as disease besieges colonies

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