WASHINGTON, D.C. - When a virus was discovered in Jim Lerew's Pennsylvania peach orchard in 1999, all 160 acres of trees had to be destroyed.

He hasn't planted any replacement trees since then for fear the virus would attack them, too.

The only way to halt the spread of the virus is to destroy the entire orchard that is infected, and that's a risk a grower can't afford to take when an acre of fruit trees can be worth $10,000.

"That's a difficult situation to get enthused about planting under," Lerew says.

But the government soon could approve the first fruit trees that have been genetically engineered to resist this virus, known as the plum pox, which attacks several types of trees, including plums, apricots, peaches and cherries.

It will be a milestone for agricultural biotechnology, which has so far mostly been limited to field crops like corn, soybeans and cotton.

The biotech trees also are unusual in that they were developed in the public sector and through collaboration between scientists in the United States and Europe, where the virus has destroyed 100 million trees.

Scientists found that trees can be made immune to the virus by inserting into the trees a gene from a virus protein.

Similar work earlier on papayas has been credited with saving Hawaii's papaya industry.

"I think it's a step in the right direction," Lerew says of the advance in biotechnology. "You still have to grow a piece of fruit that the consumer desires."

You also have to persuade the public to accept the idea of genetically engineered fruit.

"It's not a problem unless the consumers find out about it, which they probably will," says Lerew. "But we have to get over that."

The trees were developed by scientists who work for an arm of the U.S. Agriculture Department - the Agricultural Research Service. Another division of USDA - the Animal and Plant Health Inspection Service - will decide whether the trees, dubbed Honeysweet, are safe for the environment and public health and can be commercialized.

If the trees are approved for commercialization - and that appears likely - USDA would then offer to license the technology to tree producers.

USDA has received hundreds of letters and e-mails from people who argue that the pollen from the trees could contaminate conventional or organic orchards or that there isn't enough known about the safety of genetically engineered food.

The critics also don't like that USDA is both the developer and the regulator of the technology.

A typical concern in the comments to USDA: "People who care about what they eat do not want foods that have been tinkered with in their food supply."

The scientists at USDA responsible for evaluating the safety of the trees concluded that there is no danger to the environment.

Kent Bradford, director of the Seed Biotechnology Center at the University of California-Davis, agrees. Extensive trials of the trees over the past decade have shown that they are both safe and effective, he wrote USDA.

But the question still remains about whether consumers will buy biotech fruit.

A fresh peach, after all, is not quite the same as, say, soy lecithin or corn oil, food ingredients derived from crops that are genetically modified.

"Consumers probably feel a little bit differently about things they consume directly, fresh fruits and vegetables," says Michael Fernandez, executive director of the Pew Initiative on Food and Biotechnology.