U.S. beekeepers lost 44% of colonies in year to April
The results of the survey, which was completed by both commercial and small-scale beekeepers, showed both summer and winter losses worsened considerably, marking the second consecutive survey year in which summer loss rates rivalled winter losses.
"We're now in the second year of high rates of summer loss, which is cause for serious concern," said Dennis vanEngelsdorp, an assistant professor of entomology at the University of Maryland and project director for the Bee Informed Partnership which conducted the survey.
"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."
Almost 6,000 beekeepers responded to the survey, which is now in its tenth year, representing about 15 percent of domestically kept bees in the U.S.
Beekeepers’ losses of 44.1 percent of colonies marks an increase of 3.5 percent over the previous study year (2014-15), when loss rates were 40.6 percent.
Winter loss rates increased from 22.3 percent in the previous winter to 28.1 percent this past winter, while summer loss rates increased from 25.3 percent to 28.1 percent.
According to researchers, pests and disease are amongst a number of factors behind the losses.
They said one clear culprit is the varroa mite, a lethal parasite that can easily spread between colonies, but added that pesticides and malnutrition caused by changing land use patterns are also likely taking a toll, especially among commercial beekeepers. ■