Washington, May 7 (EFE).- The population of honeybees in the United States declined by 31 percent last winter, a situation that endangers a number of crops requiring bees for pollination, the Department of Agriculture said Tuesday.
A study released by the federal agency warned that the survival rate of bee colonies is too low to ensure that pollination needs are met for U.S. crops.
According to the figures presented in the report, bee colonies have been reduced by 800,000 nationwide and the cause for this so-called "colony collapse disorder" it not clear. The recent reduction in the number of bees has been sharper than the ongoing decline in the bee population that has been under way since 2006.
During the winter of 2011-2012, the number of bee colonies dropped by 22 percent.
In the United States, more than $20 billion worth of annual crop harvests - everything from almonds to pears - depend on pollination by honeybees.
Almonds are the main crop needing bees for its pollination, especially in California, where it is a $4 billion-per-year industry that requires about 60 percent of the currently-existing bee colonies.
But honeybees pollinate almost 100 flowering crops, including apples, nuts, avocados, soybeans, asparagus, broccoli, citrus fruits and cranberries. About a third of the human diet is made up of plants pollinated by bees and the honeybee, in particular, is responsible for 80 percent of that pollination.
"We're just one adverse climatological event or one big loss of bees in winter away from a pollination disaster," said scientist Jeff Pettis, one of the report's authors.
However, scientists have not found a single, well-defined cause for the decline in the bee population and, instead, point to "multiple factors."
Among those factors, they cite exposure to certain pesticides, parasites, poor nutrition, loss of habitat and other diseases.