Beekeepers across the United States lost 44 percent of their honeybee colonies in the past year, nearly as bad as losses sustained in 2012-13, according to a survey by researchers. Losses were more than twice the economically acceptable rate for owners of the pollinators that add an estimated $15 billion to U.S. agriculture through higher yields.
High rates of population loss in colonies has been a vexing problem for more than a decade. The leading causes are thought to be parasites such as the Varroa mite, disease, poor nutrition and pesticides. Researchers say the Varroa mite is a clear culprit. Environmentalists want to restrict use of neonicotinoids, a popular pesticide among farmers and gardeners.
“We’re now in the second year of high rates of summer loss, which is cause for serious concern,” said Dennis vanEngelsdorp, project director of Bee Informed Partnership, which began surveying colony losses in 2006. “Some winter losses are normal and expected. But the fact that beekeepers are losing bees in the summer, when bees should be at their healthiest, is quite alarming.”
Annual losses hit 45 percent in the year ending in April 2013, fell to 34 percent the next year and began climbing again, to nearly 41 percent last year and 44 percent in the latest survey. Summer and winter losses rates were the same — 28 percent — in 2015-16.
“The high rate of loss over the entire year means that beekeepers are working overtime to constantly replace their losses,” said USDA entomologist Jeffery Pettis, a co-coordinator of the survey. The USDA provides funding for Bee Informed.
The agency is to release today its first Honey Bee Colonies report, based on a survey of beekeepers. Topics will include the number of colonies, colonies lost, colonies added and colonies affected by certain stressors.
Varroa mites are more abundant than previously thought and are linked to several damaging viruses, according to a recently published study. The mite is a particularly challenging parasite for small-scale beekeepers, says Bee Informed.
“Many backyard beekeepers don’t have any Varroa control strategies in place. We think this results in colonies collapsing and spreading mites to neighboring colonies that are otherwise well-managed for mites,” said Nathalie Steinhauer, a University of Maryland graduate student who leads data collection efforts in the annual survey.
More than 5,700 beekeepers, responsible for 15 percent of the estimated 2.66 million managed honeybee colonies, took part in the 2015-16 survey.
“About one mouthful in three in our diet directly or indirectly benefits from honeybee pollination,” says USDA’s Agricultural Research Service. “Commercial production of many high-value and specialty crops like almonds and other tree nuts, berries, fruits and vegetables depend on pollination by honey bees.”