Saturday, February 23, 2008

Hard winter for honeybees

Local beekeepers attribute unusual loss of hives to strange disorder, many other factors


Sonoma County beekeepers are reporting significant losses among their honeybees this winter including what some describe as cases of Colony Collapse Disorder, the mysterious scourge that has wiped out thousands of colonies around the nation.

Some local beekeepers have lost up to two-thirds of their inventory, though the reasons remain unclear.

"You can ask 100 beekeepers and get 100 different answers," Sebastopol beekeeper Glen Murphy said.

The losses are critical because honeybees play an important role in crop production by pollinating about 130 different fruits, nuts, vegetables and berries, adding an estimated $18 billion annually to national crop values, the U.S. Department of Agriculture reports.

About one in three mouthfuls consumed by the average American is the direct or indirect result of pollination, USDA Agricultural Research Service spokeswoman Kim Kaplan said.

But honeybees are not native to North America. And while there are feral colonies, they do best when managed by beekeepers now desperate to discover what's killing the bees.

Many beekeepers cited poor nutrition due to inadequate rainfall and the early disappearance of nectar-abundant flowers last fall as a likely factor.

Mike Johnson, president of the Sonoma County Beekeepers Association, believes some of his bees succumbed to starvation, freezing temperatures or a combination of the two.

But four hives showed symptoms of Colony Collapse Disorder, or CCD, a catch-all phrase developed in 2006 to described massive colony die-offs around the United States and elsewhere.

"Basically, I had 12 hives, and now I'm down to one," Johnson said.

The classic sign of CCD, whose cause is still undetermined, is that affected hives are basically empty of adult bees or corpses, save for a live queen in most cases, and a small number of larvae or brood. There's also usually plenty of honey.

In the developing CCD research, that's about the only way to determine when it's hit, UC Davis entomologist and beekeeping expert Eric Mussen said.

Though scientists have mounted several research projects since reports of mass collapses began, examining potential links between parasites, viruses and other pathogens, they remain stumped.

"It would be real nice to make it simple and clear-cut and say, 'It's this,' but we're not there yet," Kaplan said.

Her agency, like many researchers, suggests a "perfect storm" of stressors that have compromised bees' immune systems, making them more susceptible to existing or still-unidentified pathogens.

"Right now we're still thinking it's just a number of, I don't know, all the things that are stressful to bees sort of ganging up on them and hitting them at one time," Mussan said.

Some level of hive loss is natural during the winter, when the bees cluster together with whatever stores of honey they can gather to try to stay warm and healthy.

The queen bee, meanwhile, lays some eggs in December and kicks into high gear producing eggs in January.

But the queen may fail to produce enough larvae to replace short-lived adults. There may be starvation, if stores are inadequate, or too small a population to maintain a high enough temperature.

An increasing variety of parasites, especially mites, viruses and diseases have contributed to a steady decline in bee populations, which are also impacted by pesticides.

Managed bee colonies, estimated at 5 million in the 1940s, have been cut to about 2.5 million, according to the Department of Agriculture.

California almond growers alone require about 1.2 million colonies to pollinate the crop, the California Almond Board said.

Demand for bees increasingly means large commercial beekeepers truck their hives around the state and country, for a price.

Some beekepers blame the species' fragility in part on the stress of being trucked and the intermixing of species from different regions.

Sonoma County -- what Sebastopol beekeeper Doug Vincent described as "very close to bee heaven" -- boasts a number of commercial honey producers.

But few are part of the migrating pollination force.

One who is, Fulton beekeeper Hector Alvarez, has hundreds of hives at work in the Central Valley for the almond season.

He said he lost about 100 of his 700 or so colonies over the winter, but said he thinks the problem affecting most area hives is Varroa mite, a widespread pest that disables developing bees before they hatch.

Kathy Cox, who owns Bloomfield Bees Honey, attributed her losses of more than a third since July to everything from predatory yellowjackets, a bacterial disease called American foulbrood and harsh weather conditions to genetically engineered plants and the pesticides in flea-control products.

Vincent, who with his wife owns beekind honey shop in Sebastopol, said he's down to about 65 hives from 120 last season.

But he said he escaped CCD, instead losing weaker hives to normal attrition.

What marks CCD is rapid destruction of a colony that appears to be thriving weeks or days before.

That is what's so frustrating, said Ettamarie Peterson of Peterson Farms in Petaluma.

"You always lose some, maybe because they weren't all that great a hive to begin with," said Peterson, who lost six of her 11 hives this winter.

Several of them, she said, were weak going into the season, but two were so strong and healthy she hoped to split them into separate hives soon.

"Before, I was reading all this stuff (about CCD) and patting myself on the back and saying, 'Well, my hives are OK.' And now it's hit home," she said. "All of a sudden malaria has come to town."

You can reach Staff Writer Mary Callahan at 521-5249 or mary.callahan@pressdemocrat.

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