Bees are essential to life because they pollinate plants. (HEINZ-PETER BADER/REUTERS)

Honeybees are disappearing in United States, and there’s new information on the reasons why.

A recent government report puts the blame on a parasitic mite (a tiny spiderlike creature that feeds on other species), viruses, bacteria, poor nutrition, genetics, loss of living areas and pesticides.

The many causes make it harder to do something about what’s called colony collapse disorder, experts say. The disorder has caused as many as one-third of the nation’s bees to die each winter since 2006.

Bees, especially honeybees, are needed to pollinate crops. They are a necessary link in the food supply.

The federal report, issued last week by the Agriculture Department and the Environmental Protection Agency, said the biggest culprit is the parasitic mite, called Varroa destructor.

Colony collapse disorder has also hit bee colonies in Europe, where government officials are considering a ban on a type of pesticide that some environmental groups say is to blame. The U.S. report puts some blame on pesticides but ranks them near the bottom of the list of factors. Federal officials and researchers advising them said there’s not yet enough scientific evidence to warrant banning the pesticides.

The report is the result of a large conference of scientists that the government brought together last year to figure out what’s going on. Participant May Berenbaum, a top bee researcher from the University of Illinois, said there is no proof that the group of pesticides known as neonicotinoids is the only culprit in the bee loss.

Berenbaum said she doubts that banning neonicotinoids would have any effect on bee health. She was the chairwoman of a major National Academy of Sciences study on the loss of pollinators.

Dave Gaulson of the University of Stirling in Scotland, who conducted a study last year that blamed the chemical, said he can’t disagree with the overall conclusions of the U.S. government report. However, he said, it should have emphasized pesticides more.

Agriculture Department bee researcher Jeff Pettis said modern farming practices often leave little area for bees to find food.

Berenbaum said that there’s no single solution to the problem and that scientists and government agencies aren’t able to tackle all of the causes at once.

— Associated Press