Following the Bush administration announcement that employers who knowingly keep undocumented workers will be held liable under a new enforcement push, many growers said their businesses would be hardest hit.

Particularly vulnerable would be fruit operations that are now hiring thousands of seasonal workers in preparation for the peak harvest months of July through September. The measure is to take effect in mid-September.

Andy Casado Jr. is a California farm labor contractor with nearly 800 workers who also grows and packs fruit himself.

"I'm guessing 80, 90 percent of the ag work force is illegal," he said. "Implementing this rule will be catastrophic."

One northeast Georgia poultry executive has been quoted as saying illegal labor is "indispensable" to the country's economy.

While it's long been illegal to hire anyone not authorized to work in the United States, farmers take their chances that documents presented by the 1.6 million farmworkers around the country are valid, said Howard Rosenberg, a farm labor at the University of California.

Think tanks that oppose illegal immigration praised the move, hoping it will turn off the job magnet has attracted new immigrants.

To farm workers, though, it's just another effort by the government to look good at the expense of the people who hold down the hardest and lowest paid jobs in the country.

"There's always more pressure on the immigrant community,'' said farm worker Gerardo Reyes of Immokalee, Fla. ``We're making sure food gets to everyone's tables."