* Brown increases support among Latino voters
* Whitman camp says poll is old, out of sync with others
* Calif. marijuana legalization looks headed for defeat
* Boxer narrowly leads Republican challenger Fiorina (Adds comment from Whitman campaign, paragraphs 5-6)
LOS ANGELES, Oct 24 (Reuters) - Democrat Jerry Brown has more than doubled his lead over Republican rival Meg Whitman in the California governor's race, gaining support from Latino voters after an illegal immigration furor over the former eBay chief's former housekeeper.
A Los Angeles Times/University of Southern California poll on Sunday gave Brown, the state's attorney general who first served as California governor from 1975 to 1983, a 13 percentage point lead over Whitman. Brown has 52 percent support, compared to 39 percent for Whitman among likely voters.
In the same poll a month ago, Brown had a 5 percentage point lead over Whitman. The election is Nov. 2.
Sunday's poll, conducted Oct. 13-20, showed Brown has a 36 percentage point lead over Whitman among Latino voters, up from 19 percent in September.
Latinos make up a fifth of the California electorate and are seen as pivotal in deciding the governor's race.
Whitman's camp on Sunday dismissed the poll as old and inaccurate given that three more recent surveys show her gap with Brown to be nearer to 3 percentage points.
"Statistically, given the clear average of multiple public and private polls fielded in a similar time frame, the LA Times poll should be categorized as an outlier poll and can be dismissed as simply inaccurate," said Whitman pollster John McLaughlin.
The poll also found that three-term Democratic U.S. Senator Barbara Boxer maintains an 8 percentage point lead over Republican challenger Carly Fiorina, the former Hewlett-Packard CEO.
MAJORITY OPPOSE LEGAL MARIJUANA
In other findings, California's ballot measure to become the first U.S. state to legalize and tax marijuana is opposed by 51 percent of likely voters, compared to 39 percent in favor -- most of them young, white men.
Whitman, a billionaire political novice making her first run for office, has poured some $140 million of her own money into a bid to beat Brown in a year when voters, angry over the still-sluggish economy and high unemployment, are expected to punish Democrats at the ballot box.
Sunday's poll showed, however, she had taken a hit from revelations last month that she employed, and later fired, an undocumented Latina housekeeper.
Some 52 percent of likely voters thought Whitman handled the issue poorly, compared to 41 percent who said she handled it well.
Whitman, who supports a guest worker program but no citizenship for those in the United States illegally, may also have been damaged by some hard-line comments on immigration in a televised Spanish-language debate, University of Southern California researchers said.
"There are events beyond her control that Whitman didn't manage well," said USC political scientist Darry Sragow, the interim poll director. "Voters are making a judgment about Whitman's character and how she handled a crisis."
California has been considered a reliably Democratic state but has elected a string of Republican governors since the 1960s, including former President Ronald Reagan and current Governor Arnold Schwarzenegger.
The new governor will inherit a state struggling with double-digit unemployment, a budget deficit of tens of billions of dollars and an unpopular, often gridlocked legislature.
The Los Angeles Times/University of Southern California survey was conducted among 1,500 people, including 922 likely voters. The poll has a margin of error of plus or minus 3.2 percentage points for likely voters.
(Additional reporting by Dan Whitcomb, Editing by Sandra Maler)