MARION — Farmers are angry about an increasing number of crop circles popping up in their fields, costing them time and money.

The circles — crops that have been flattened to form geometric patterns — have nothing to do with supernatural or extraterrestrial beings. Farmers say it's probably rambunctious teenagers vandalizing their fields.

"Aliens don't typically leave beer cans or tire tracks," said Ron Burkhart of Bucyrus, about 60 miles north of Columbus.

About a dozen cases of crop circle vandalism have been reported in nearby Marion and Crawford counties. Bucyrus farmer Richard Grau said he's never seen more widespread damage in 40 years of farming.

Crawford County has extra sheriff's deputies on patrol at night, said Sheriff Ron Shawber. He's investigating seven crop circle reports in recent weeks. But finding the vandals on miles and miles of corn-lined roads has proved a difficult task.

Authorities said whoever is making the crop circles drives a large four-wheel vehicle and knows the area well.

"The farmers, they're upset," Shawber said. "I wouldn't want to be out in the field and get caught by them."

Bucyrus farmer Terry Crall said he'd punish the vandals by making them pick up the ruined corn one-by-one. Crall found misshapen circles cut into his 550 acres just weeks before the fall harvest. He estimated the damage at $470 for an acre of lost crops and the extra work he'll have to do next year to make sure the fallen corn doesn't spoil crop rotation.

"It's just mindless waste," Crall, 62, said. "It's a lack of respect for the corn plant and the process of growing food."

And while farmers can collect insurance on crop damage caused by weather and wildlife, vandalism isn't usually covered, said Chely Broerman, office manager of Broerman Insurance Agency in Fredericktown. Some damage falls under property and casualty policies.

"We don't get rich out here, and it just really ticks you off that they just go out and want to destroy stuff," Grau said. "That's the worst part of it. I can see having fun, but let's not get so destructive."

The Crawford County Farm Bureau is offering a $1,500 reward for information leading to the arrest and conviction of the culprits, who could face felony vandalism charges.