California growers are worried the latest crackdown on undocumented workers could end up creating a severe labor shortage, NBC11's Daniel Garza reported.

California growers estimate that as many as nine out of 10 of their workers are undocumented. They said that without them, crops would not get harvested.

New requirements by the U.S. Department of Homeland Security could force employers to monitor the fraudulent use of Social Security numbers and create a shortage of workers.

"It's totally necessary for California and agriculture to survive in the United States to have some kind of bill put in where workers can come over, and even if it's just the old Bracero Program, where they can come in to do the work and go back to Mexico -- but the workers are needed to harvest the crops especially here in California," said Bill Christopher of Christopher Farms.

There already is a guest worker program, but growers said it doesn't allow for enough workers and it has too much red tape to make it practical.

A new guest worker program won't materialize until Congress passes comprehensive immigration reform, which won't happen until at least after the 2008 presidential election, Garza reported.

Growers said the full brunt of a labor shortage would likely be felt next year.