A federal report released on May 2 said there is no one cause for the collapse of honeybee populations since 2006.
It is a complex and intertwined set of causes, a combination of viruses, bacteria, substandard nutrition, loss of habitat, and pesticides, among other factors, revealed the U.S. Department of Agriculture (USDA) and the Environmental Protection Agency (EPA) in a joint study.
By far "the single most detrimental pest of honeybees" is the parasitic mite varroa destructor, the Associated Press reported. Although pesticides were listed by the U.S. as one cause of the mysterious decline, they were not considered a major factor, whereas in Europe certain pesticides were recently banned because of their detrimental effect on honeybees.
"It is not clear, based on current research, whether pesticide exposure is a major factor associated with U.S. honeybee health declines in general, or specifically affects production of honey or delivery of pollination services," the U.S. report said. “It is clear, however, that in some instances honeybee colonies can be severely harmed by exposure to high doses of insecticides when these compounds are used on crops, or via drift onto flowers in areas adjacent to crops that are attractive to bees."
Two new studies published last March found that the pesticides seemed to disrupt the bees' sense of direction so that they had trouble finding it back to the hive. (Related: Two Studies Tie Mysterious Decline in Bee Populations to Specific Pesticides)
On April 29 the European Commission imposed a two-year moratorium on use of pesticides containing neonicotinoid chemicals, which are the ones thought to harm bees. The ban will be in effect for the EU’s 27 member states by the end of the year. The three pesticides involved are clothianidin, imidacloprid and thiametoxam, The Guardian reported.
"The science is sufficiently strong to make it worth taking certain measures now. The costs in the short term are worth it given the potential costs over the long term," European Commission spokesman Roger Waite told CNNMoney.
Although farmers and crop experts countered that the data are insufficient, 15 countries voted to impose the ban, which was not enough of a majority for a permanent restriction, BBC News reported.
Neonicotinoid pesticides are chemicals with a makeup similar to nicotine that disrupt an insect’s nervous system, BBC News said. Sprayed onto seeds or applied to soil before planting, neonicotinoids are systemic, meaning they are taken up by the plant as it grows and essentially make the plant itself poisonous to pests. Mammals and the environment are thought not to be much affected by this type of insecticide.
U.S. researchers said that the numerous causes of colony collapse disorder make it extremely hard to treat.
"We're not really well equipped or even used to fighting on multiple fronts,” admitted May Berenbaum, a bee researcher at the University of Illinois, to the Associated Press.
One solution could come from the bees themselves. Another study, this one published on April 29, 2013 in the journal Proceedings of the National Academy of Sciences, suggested that chemicals in honey could enhance bees’ ability to fend off parasites and pesticide damage, according to LiveScience.com.
"The natural honey has components in it that help trigger defenses in the bees," Jay Evans, a USDA bee pathologist not involved in the study, told LiveScience.
At stake on this side of the Pond is the approximately $30 billion a year part of the agriculture industry that depends on healthy bees for pollination, the USDA's Sonny Ramaswamy told AP.