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Bat disease could allow insects to destroy crops

April 27, 2011


A deadly disease to bats could become a major financial headache for agriculture, costing Ohio farmers as much as $1.7 billion a year.

A new study is the first to tie a dollar value to the millions of crop-damaging insects that bats routinely devour each year. Now, the night-flying hunters face the threat of a fungal disease that kills most of the bats it infects.

White-nose syndrome, named for the fungus that spreads over bats while they hibernate, has killed at least 1 million bats in 15 states and Canada since it was discovered in New York in 2006.

On March 30, Ohio officials announced that they found the disease among bats hibernating in an abandoned limestone mine in the Wayne National Forest. They fear it will march through Ohio as it has nearly everywhere else.

“It’s serious,” said Katrina Schultes, a Wayne National Forest wildlife biologist. “There is anywhere from 80 percent up to 99 percent mortality, and, at this point, there is no cure.”

In the April edition of the journal Science, researchers estimate that U.S farmers would see annual economic losses of $3.7 billion to $53 billion if the nation’s bat population were wiped out.

Losses to Ohio farmers would range from $740 million to $1.7 billion a year through a combination of crop damage and costs to purchase additional pesticides.

The biggest losses, according to the study, would be felt in Darke, Putnam, Mercer, Wood and Pickaway counties, which have the most land in crop production. Losses in each county would range from $3million a year to more than $40million.

The estimates are based largely on studies that examined the benefits of bats to Texas cotton growers.

The spread of the disease in Ohio hasn’t been determined, Schultes said. A check of a well-known bat-hibernation area in Preble County found no sign of the disease.

But most of the areas in southern Ohio where bats tend to hibernate, including long-abandoned coal mines, are either inaccessible to people or unsafe to explore, she said.

Bats are prodigious insect eaters. Studies have shown that a single colony of 150 big brown bats can eat as many as 1.3 million insects a year.

White-nose syndrome causes bats to burn through their fat reserves before winter ends, leaving them starving and with no insects to hunt for food.

Paul Cryan, a U.S. Geological Survey research biologist and a co-author of the study, said the estimates should serve as a starting point for a discussion of bats’ importance to people.

In Ohio, bats eat pests that include cucumber beetles, stink bugs and leafhoppers, said Marne Titchenell, an Ohio State University Extension wildlife program specialist.

By eating moths that develop from crop-damaging worms, bats break the reproductive cycle, Cryan said.

Bats “are tremendously valuable creatures,” Cryan said. “We think it’s worth the effort now, to try to protect these (bat) populations.”

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