University of California-Davis
An annual survey of commercial beekeepers shows a decline in the number of hives lost over the winter, but concerns about bee health remain and the cause of colony collapse disorder is unresolved.
The USDA said 23.2 percent of managed honey bee colonies died off over the 2013-14 winter. That’s an improvement compared to the 30.5 percent loss reported in the 2012-13 survey and below the eight-year average of 29.6 percent. In this year’s survey, commercial beekeepers identified a die-off rate of 18.9 percent as the limit of economic sustainability. Two-thirds of this year’s respondents reported rates above that mark.
In a news release, USDA chief researcher Jeff Pettis said the yearly fluctuations “demonstrate how complicated the whole issue of honey bee health has become.” A combination of viruses, pathogens, parasites, pesticides and lack of nutrition diversity are thought to weaken and kill colonies, said Pettis, co-author of the survey and research leader of the Agricultural Research Service (ARS) Bee Research Laboratory in Beltsville, Md.
Pacific Northwest beekeepers didn’t fare better than their counterparts elsewhere.
Washington keepers lost about 42 percent of their bees over the winter, said Mark Emrich, president of the Washington State Beekeepers Association. Emrich based his estimate on information he gathered from eight of the state’s 26 local beekeeper associations.
Emrich believes verroa mites, lack of forage and pesticides are responsible for the decline in Washington state.
Mites reduce bee numbers to the point they are unable to form the large hive balls necessary to keep themselves warm in winter, he said. Meanwhile, the campaign by state and local governments to remove invasive weeds has cost bees a valuable forage source. Many noxious or invasive weeds, such as Scotch broom, are flowering plants that provide food at distinct points in the calendar.
“As they take this stuff out, they’re not replacing it with anything,” said Emrich, who has 21 hives at his home south of Olympia and describes himself as a craft beekeeper. “Certainly mono-culture farms don’t help much either — one bloom and after that it might as well be a desert as far as bees are concerned.”
Emrich said even home gardners can help by using alternatives to pesticides and herbicides.
“If you can pull it, burn it, mow it — do anything else besides whip out the pump bottle,” he said. “You have no idea how many bees you’re saving in the long run. If you’ve got aphids, buy ladybugs.”
Oregon survey figures haven’t been finalized. Paul Andersen, president of the Oregon State Beekeepers Association, said commercial keepers may have kept losses at 25 percent or less, but hobbyists may have seen 40 to 50 percent losses.
Like most researchers and keepers, he believes a combination of factors are causing problems for bees. He acknowledged there are some in the industry who think the neonicotinoid class of insecticides is causing colony collapse disorder.
“There is a group who will stand up and say that is the smoking gun, but the evidence isn’t really there yet,” Andersen said. “Everyone agrees it’s one of the straws breaking the camel’s back, but verroa mites are a bigger piece of straw.”
Pollinators, including commercial bees trucked up and down the West Coast as food, seed and forage crops come into season, are responsible for pollinating 75 percent of the world’s flowering plants, according to the USDA.
The survey includes responses from 7,183 U.S. beekeepers who managed a total of 564,522 colonies in October 2013, 21.7 percentof the country’s 2.6 million colonies.