GREENE COUNTY — Think the 2009-10 winter was tough on you? Consider the state’s honeybees.

An estimated 50 to 70 percent of hives kept by beekeepers died, said Cindy Kalis, spokeswoman for the Ohio Department of Agriculture.

The losses are in keeping with heavy fatality rates experienced since 2006 — a year when 600,000 bee colonies in the U.S. mysteriously fled their homes and disappeared, said James Tew, Ohio State University’s state honeybee specialist.

“The average person should care,” he said. “Bees of all species are fundamental to the operation of our ecosystem.”

Without bees to pollinate vegetables like squash and fruits like pears, apples and blueberries — a third of the human diet — you’d be looking at a menu of wheat and corn, Tew said.

Bees annually pollinate Ohio crops worth $44 million, including berries, fruits and vegetables. Honey sales yield $1.4 million, according to Agriculture Department entomologist Barb Bloetscher.

Honeybees are under siege from many foes: Destructive mites, too many pesticides showing up in pollen, a mysterious disorder that causes them to abandon hives, stress from overwork to pollinate cash crops.

In the 1920s, Ohio beekeepers kept 120,000 colonies. Today, there are about 30,000.

“How low should these numbers go before it’s a crisis?” Tew asked. “Do you wait until you can’t get vegetables? The public should be concerned.”