A federal study attributes the massive die-off in American honey bee colonies to a combination of factors , including pesticides, poor diet, parasites and a lack of genetic diversity. Nearly a third of honey bee colonies in the United States have been wiped out since 2006. The estimated value of crops lost if bees were no longer able to pollinate fruits and vegetables is around $15 billion.

The report comes on the heels of an announcement Monday by the European Union that they are banning the use of pesticides that may be harmful to bees for two years. The measure is being closely watched here because the insecticides, known as neonicotinoids, have been in wide use for the past decade. Many studies, including the study released today by the USDA, have made a link between the insecticides — which are used to ward off pests such as aphids and beetles — and honeybee deaths. European researchers will conduct further experiments over the two-year period to assess whether the chemicals are a contributing factor in “colony collapse disorder.”

U.S. beekeepers have been reporting annual hive deaths of about 30 percent or higher for much of the past 10 years, but this past winter marked the worst loss ever — nearly 40 to 50 percent or more. The loss was so bad that California’s almond growers had to scramble to find enough bees to pollinate the state’s 800,000 acres of almond trees this spring. Tim Tucker, vice-president of the American Beekeeping Federation and owner of Tuckerbees Honey, which lost half of its hives this past winter, told The Guardian: “Other crops don’t need as many bees as the California almond orchards do, so shortages are not yet apparent, but if trends continue, there will be. Current [bee] losses are not sustainable. The trend is down, as is the quality of bees. In the long run, if we don’t find some answers, and the vigor continues to decline, we could lose a lot of bees.”

In a “show of concern,” the Environmental Protection Agency sent three representatives to the San Joaquin Valley in California for discussions. A coalition of beekeepers, environmental and consumer groups sued the EPA last week for its failure to protect bees from harmful pesticides.

In Europe, the decision to institute the moratorium was not without controversy. BBC News reports that leading up to Monday’s decision, lobbying was “ferocious” on both sides. Nearly three million signatures were collected in support of a ban. Chemical and pesticide manufacturers argued that the science is inconclusive and that a ban could inhibit food production.

Experts at the USDA, EPA and others involved in the federal bee study concluded that there was not enough evidence to support a ban in the United States, and that the cost of imposing one could outweigh the benefits. They recommended further research be done.

Jay Feldman, the executive director of Beyond Pesticides, said in a statement, “we’re happy to see the EU take a leadership role to remove from the market these chemicals associated with colony collapse disorder and hazards to bee health. We’ll continue to push EPA through legal and advocacy means to follow-up with urgent actions needed to protect bees.” Find out more about the BEE Protective campaign and how you can protect wild bees in our Take Action section.

Watch Dance of the Honey Bee, a short film by Peter Nelson, narrated by Bill McKibben.