Agencies: Disappearing bees caused by swarm of factors

"Modern farming practices are leaving very little land for bees and other pollinators at this point," said Jeffery Pettis, the leader of bee research at the USDA's Agricultural Research Service, on a conference call with reporters.

One major factor for honeybee decline, the report finds, is a parasitic disease-carrying mite that can withstand the chemicals beekeepers use. New species of the tick-like bugs, known as the varroa mite, have been discovered in the country, which analysts have linked to the bee decline.

According to the report, the mite "remains the single most detrimental pest of honeybees, and is closely associated with overwintering colony declines."

Additionally, bee populations have been plagued by poor nutrition, increased pesticide exposure and lack of genetic diversity, which causes bees to be unable to withstand diseases or fluctuations in temperature.

The report lists a series of best management practices that farmers and beekeepers should consider to help colonies thrive, but steers clear of swift regulatory action.

The European Union this week began to roll out a two-year ban on three pesticides that have been linked with declining bee populations.

The Obama administration, however, is reluctant to blame pesticides solely for the declining bee colonies.

"As a matter of policy, we let the science lead our regulatory decision-making, and we want to make sure that we make accurate and appropriate regulatory decisions as opposed to things that could lead to meaningful societal cost without any benefit whatsoever," said Jim Jones, acting EPA assistant administrator for chemical safety and pollution prevention.

Instead, the report notes that more information is needed on pesticides' effect on bees and urges reporting bee deaths and inspecting bee yards as a tool to collect data.

In a statement, American Farm Bureau Federation President Bob Stallman said that the report "concludes what farmers and scientists have known for some time—that there isn’t just one cause to the decline in honey bee numbers."

The findings make "it even more important that we continue work on a solution through collaborative efforts among farmers, beekeepers, researchers, the federal government and the public," he added.

Bee pollination is credited for the existence of up to one-third of all food and beverages, and affects up to $30 billion in annual agricultural crops.

"There is an important link between the health of American agriculture and the health of our honeybees for our country's long term agricultural productivity," said USDA Deputy Secretary Kathleen Merrigan in a statement announcing the report.

"The forces impacting honeybee health are complex and USDA, our research partners, and key stakeholders will be engaged in addressing this challenge."

This post was updated at 3:39 p.m.