In Washington Courthouse, Ohio, angry calls reporting teen-age vandalism come in about twice a week now.

"That's a lot more than we used to get -- none, except for Halloween, of course," says Sheriff Donald Thompson.

In Bemidji, Minn., Sheriff Tom Tolman tries to puzzle out the periodic rashes of vandalism that have been flaring up in his northern Minnesota county. "Hey," he says, "kids just have a lot more temptations today."

And when teen-agers knocked over the sheriff's mailbox and then ran their pickup back and forth across it in Texas' rural Marshall County, a local lawman complained, "It just seems like these county kids are breaking things and stealing things these days like we've never seen before."

All across the nation's farm belt the stereotype of the hard-working rural youngster, who had no time or energy left after chores to get into trouble, is fading -- like the family farm itself.

It is no surprise that crime in rural areas is up. Federal crime statistics show that all kinds of rural crime has climbed 407 percent in the last 20 years. But along with that increase -- which includes major crimes such as murder, armed robbery and rape -- juvenile crime and vandalism caused by young people out in the country has quietly increased at an even faster pace.

"Property theft in the rural areas has gone up 916 percent in the last 20 years," said David Phillips, the director of the National Rural Crime Prevention Center at Ohio State University. "I would argue that vandalism and other youth-type problems in rural sections of the country have climbed at a rate equal [to] or more than that."

When a research team from the Ohio State center studied youngsters in rural Ohio last year, they were startled to find that more than half of the teen-agers admitted to committing some type of vandalism. A similar study in Indiana this year showed 42 percent of the youths had been involvewd in vandalism.

"It appears that no matter where you live today you are not going to escape the same problems that we have always attributed to city youthh in the past," said sociologist Kathleen Natalino.

Natalino, a researcher at the University of Akron, compared farm area teen-agers with a similar group of youngsters from a large midwestern city last year and found that the two groups appeared to be almost equally prone to committing acts of vandalism and other petty crime.

But while the frequency of youth crime may be similar for country and city, there is a major difference in the types of crime being committed, said Natalino. Rural teen-agers, for example, are not nearly as likely to be involved in assaults or other violent crimes. They are also less deeply into drug use, with the exception of marijuana, she said.

Instead, she said, rural young people tend to get involved in petty theft, such as shoplifting, or vandalism. A lot of the misbehavior goes unreported, especially in remote areas where there is no one around much of the time, Natalino said.

Joseph Donnermeyer, another sociologist who has looked into the problem, notes that there are even fewer people in many rural areas now than in years past.

Donnermeyer, a staff member with the National Rural Crime Prevention Center, cites statistics that indicate the traditional rural family has changed dramatically in the last 20 years.

Only about 3 percent of the nation's rural population still farms for a living. In fact, 40 percent of rural women hold jobs outside their homes. Moreover, Donnermeyer said, most rural teen-agers now attend large, consolidated high schools far from their homes.

"You used to have grandma and Uncle George around to exercise some sort of informal control," he said. "They've gone and both parents now work. That doesn't leave anybody around when a lot of teen-agers come home in the afternoon."

The increasing number of empty houses in rural areas during the day presents easy targets for vandalism and theft, Donnermeyer said.

Donnermeyer's study of Indiana rural teen-agers indicated that most were involved in vandalism, such as destroying or stealing road signs and highway markers. About 20 percent also admitted to more serious thefts and arson, he said.

"Something is happening in the rural parts of the country," he said.

"Most of these kids will grow up okay. But the mass media today hazes over the concepts of right and wrong. You take away the traditional informal controls you've had in rural areas and you lower the threshold for young people to get in trouble."

The reality behind that thesis has already hit home in Washington Courthouse. On a Friday night, dozens of pickup trucks loaded with idle teen-agers circle the streets of the rural Ohio county seat.

"People here are just sick and tired of all the foolishness," said Sheriff Thompson. In what some officials found to be an alarming illustration of that feeling, a county jury recently freed a man accused of shooting two local teen-agers who had been taunting him. The verdict was temporary insanity.

The jury's verdict came after a story hit the local papers about another local youth who was accused of stabbing two young children.

Such troubles are rare in places like Washington Courthouse. Much more typical, said Thompson, are the calls from outraged residents about petty vandalism such as smashed windows or toppled mailboxes.

"Most of it comes from rural kids who don't live on the farm," said the sheriff. "Their folks have a couple acres but they work someplace else. They're not really bad kids, they're just isolated and bored."