Colony collapse disorder (CCD)—a malady wiping out entire hives of America’s honeybees—is not going away, according to the new Colony Collapse Disorder Progress Report prepared for committees of both the United States House of Representatives and Senate. Findings show the threat is worsening and that researchers have not uncovered the main cause.

Three years ago, hives of U.S. honeybees began to mysteriously disappear—baffling beekeepers and scientists. According to the report, CCD is worsening: 20-25 percent of U.S. bee colonies died in 2006, 31 percent in 2007, and 35 percent in 2008.

The disorder strikes at the heart of the U.S. farming industry, as honeybees are a main pollinator of food crops. According to the United States Department of Agriculture (USDA), honeybees pollinate 90 percent of America’s apples, oranges, sweet cherries, grapefruit and tangerines. Almond crops rely 100 percent on bee pollination. Without it, farming profits could plummet and drastic food shortages could become reality.

The new research (which included contributions from eight federal agencies, two divisions of the USDA, 22 universities and several private researchers) concluded that while “the cause of CCD is still unknown, research has lent credence to the hypothesis that CCD may be a syndrome caused by many different factors, working in combination or synergistically.” Possible factors include inadequate diet, stressful transportation, harmful chemical pesticides, and parasites, such as the varroa mite and honeybee tracheal mite.

Researchers are exploring alternative solutions to finding the main cause and a cure: breeding mite-resistant bee stocks, irradiating wax comb prior to reuse, and using pollinators not susceptible to CCD, such as the alfalfa leaf-cutting bee, mason bees and bumble bees.