COLUMBUS, Ohio (AP) -- Ohio beekeepers lost 50 to 80 percent of their honeybees over the harsh winter, threatening the farming industry, state agriculture officials say.
Honeybees also have faced increasing numbers of diseases, pests and pesticides that have thinned colonies in recent years, according to The Columbus Dispatch .
This winter's losses come on top of 30 to 60 percent of bees dying off last year.
"It's a pretty devastating loss," said Barry Conrad, a beekeeper in Canal Winchester near Columbus who maintains 76 hives. "It's been getting worse each year."
Ohio farmers rely on bees to pollinate more than 70 crops, including apples, strawberries and pumpkins. The U.S. Department of Agriculture says honeybees pollinate more than $14 billion in crops nationwide each year.
The bitter winter didn't help, but Conrad said pesticides were the main killer. Other threats, including the Varroa mite, are spreading diseases among colonies. Bees that survive are weaker and can't endure long, cold winters.
New research suggests that pesticides can suppress the immune system, which might make bees more susceptible to mites and other pests.
"A combination of insecticides, mites and diseases are all coming together," said Reed Johnson, an entomology professor at Ohio State University who studies the effects of pesticides on bees.
Last year, Ohio had 4,390 registered beekeepers who tended an estimated 37,000 colonies at 7,199 apiaries. Since 2008, the number of beekeepers has increased by 27 percent.
Johnson said that could be why Ohio's honeybee losses tend to be higher than the national rate of about 30 percent.