Varroa mites, other factors linked to colony collapse
By JOHN O'CONNELL
A new report analyzing honeybee losses outlines a host of factors behind the problem, but singles out the parasitic Varroa mite as the major culprit.
According to a USDA report released May 2, mites have developed widespread resistance to the chemicals beekeepers use to control them within hives, and several new viruses have been found in U.S. bees.
"Consensus is building that a complex set of stressors contribute to pollinator declines, and researchers are increasingly studying multiple factors of colony losses," the report says.
Since 2006, 10 million beehives have been lost, with a replacement cost to beekeepers of $2 billion, according to the report.
The Varroa mite, first found in the U.S. in 1987, is the major cause of increasing incidences of some bee viruses, according to USDA.
The report, which will be used to update a federal action plan outlining bee-related priorities for policymakers to follow for the next five to 10 years, calls for breeding bees with increased genetic diversity to protect them against diseases.
The report also highlights how poor nutrition may be making bees more susceptible to disease and parasites, and states that broadening the variety of forage for bees could improve colony health.
The report concludes that it's unclear what role pesticides may play in colony collapse and recommends additional research. It also suggests increasing outreach to farmers to help manage bees' exposure to pesticides.
Beekeepers involved in the report also said better and more timely bee-kill incident reporting and monitoring is needed.
The report came from the Colony Collapse Disorder Steering Committee, formed in early 2007 and led by USDA and the U.S. Environmental Protection Agency, which partnered with Pennsylvania State University to convene a conference in Alexandria, Va., last October, bringing together stakeholders to study the issue.