The poll findings, based on likely voters being more Republican this year, have Democrat Jerry Brown leading Meg Whitman 49%-44%. Barbara Boxer leads Carly Fiorina 51%-43%. Brown's lead is largely due to his 19-point edge among Latino voters, and also this according to the Times story:
The Democratic candidates were benefiting from their party's dominance in California and the continued popularity here of President Obama, who has retained most of his strength in the state even as he has weakened in other parts of the country. Support for Obama may play a key role in the Senate contest, one of a handful nationally that could determine which party wins control of the chamber.
At the same time, the survey showed, Republicans Whitman and Fiorina have yet to convince crucial groups of voters that their businesswoman backgrounds will translate into government success....
Both Republicans were hamstrung by voters' negative impressions of them — particularly Whitman, who has poured a national record $119 million of her own money into an advertising-heavy campaign yet has seen her unpopularity rise, the survey showed.
Still, in this year of political tumult, the Democrats were facing stiff challenges too. As they do nationally, Republicans in California held a fierce edge in enthusiasm among likely voters. The poll defined likely voters based both on past voting history and enthusiasm about voting this year — a measure that projects an election turnout that is more heavily Republican than is typical in California. If the Democratic turnout ends up being even more sharply depressed, that would put the party's candidates at risk.
The poll is branded by the Los Angeles Times and USC's College of Letters, Arts and Sciences, but it's actually conducted by the Democratic firm of Greenberg Quinlan Rosner and the Republican firm American Viewpoint. Here's their analysis and raw data. In the last Field Poll, reported last week, Brown and Whitman were tied.