A mysterious culprit is killing millions of honeybees in dozens of states, including Wisconsin. Local beekeepers are worried that the colony collapse disorder could spread to their bees.

The disorder has beekeepers and scientists baffled, and because the bees fly off and die away from the hive, its hard to figure out just what's going on.

John Spate has been a beekeeper for more than 50 years, and it's been almost that long since he's seen a threat like colony collapse disorder.

“Back in the 60's, there was something that came then that kind of decimated the bee colonies a long time ago, but nothing like what we have today,” Spate says.

Spate has 72 colonies pollinating the apple trees at the Eau Claire Orchard- that's about 500,000 bees and Spate is concerned.

Scientists aren't sure what's responsible for the buzz-kill. One theory is that a foreign fungus or bacteria is killing the bees. Another is that insects are attacking the bees in the hive and when the bees fly off, they're too weak to make it back. One study even blamed cell phone towers, saying the signal interferes with bees' navigation. Spate also says when a hive is going to collapse, insects that usually go into hives to attack bees won't enter.

“There must be something that is creating some type of a smell or odor that is keeping those particular predators out,” Spate says.

The U.S.D.A. says bees pollinate about one quarter of our entire diet, including lots of fruit and produce.

“Everything from almonds and apples to cucumbers and melons and most of the things you're going to grow in your own garden,” says Kelly Murray, an entomologist at UW-Eau Claire.

“Peaches, pears, plums, strawberries, blueberries,” Spate adds.

If honeybees keep dying, beekeepers say there aren't any other insects to take their place.

“Our food supply will go down and the food prices will go up and we are in big trouble if that happens,” Spate says.

The U.S.D.A. is working with Congress for funding money to figure out why the bees are dying before the problem gets any worse.