A Bush administration plan for combating illegal immigration will exacerbate a shortage of farm workers in the Northwest, agricultural groups are complaining.

"Right now, there's an immense level of fear – panic – in the worker community," United Farm Workers spokeswoman Alisha Rosas tells the Capital Press, an agriculture newspaper based in Salem, Ore.

The new rules, announced in August, came after Congress failed to reach an agreement on a broader immigration bill. They require that all workers have a Social Security number that matches their name. Farmers submit both to the Department of Homeland Security. If the name doesn't match the number, a 90-day clock starts ticking, during which the worker must either provide valid documents or get fired.

If the worker leaves before then, the farmers still must prove to federal officials they tried contacting the worker, or face penalties including possible jail time.

There was already a shortage of farm workers in the Northwest. The Tri-City Herald reported in July that state farmers plowed under an estimated 7.5 million pounds of asparagus – worth $9 million – because they couldn't find workers to pick it. Shortages were also affecting the harvest of cherries, raspberries and blueberries, and work tending onions and hops was not getting done.