FRESNO -- Republican gubernatorial candidate Meg Whitman will seek to regain momentum in a debate scheduled for Saturday -- the second between Whitman and Democrat Jerry Brown.

The debate at California State University, Fresno is being hosted by Spanish-language network Univision and targets a Hispanic audience.

It follows on the heels of a tumultuous week for Whitman, in which she was confronted with allegations she knowingly had an illegal immigrant housekeeper for nine years.

Whitman maintains she did not know the immigration status of Nicky Diaz Santillan. She says when Santillan confessed to being an illegal immigrant in June 2009, she was let go.

The housekeeper's attorney, Gloria Allred, says Whitman and her husband should have suspected the worker's status because of a Social Security Administration letter mailed to their home in 2003.

The billionaire former chief executive of eBay has worked hard to court independents and Hispanics.

Her efforts have included Spanish-language radio and television ads. She took out spots during 15 games of the World Cup, as well as billboards and bus-stop posters.

Hispanics comprise 37 percent of the state's 38.6 million people and are expected to account for about 15 percent of voters on Nov. 2, according to a recent Field Poll.

Hispanic voters are crucial to the campaign of any Republican running in a state in which Democrats hold a 13.4 percentage point edge among registered voters.

She has focused a large share of her campaign account on the Central Valley, which has been hit hard by the recession and is filled with communities where unemployment affects a quarter of the population or more.

Immigration issues are expected to play a big role in Saturday's debate.

Job creation, education and water supply issues will also take center stage. Those issues are major concerns for Central Valley residents.

The first debate between Whitman and Brown was at the University of California, Davis on Tuesday.

The candidates talked only briefly about immigration. Whitman said California and other states need to stop luring illegal workers with jobs.

The housekeeper allegations against Whitman surfaced the next day.

A Public Policy Institute of California poll released this week showed Brown with only a slight lead over Whitman among Hispanic voters, but the survey was taken before the housekeeper controversy began dominating the race.

Brown and his supporters also are actively courting Hispanic voters.

The state's largest public employee union, the Service Employees International Union, is launching an ad campaign coinciding with Saturday's debate.

It will try to keep the housekeeper controversy fresh in the minds of Hispanic voters.

The $5 million Spanish-language media campaign accuses Whitman of saying one thing in her Spanish-language campaign ads and another when she speaks in English.