Geraldine Ferraro is adding the ingredient that had been missing in Walter Mondale's campaign recipe: excitement. The challenge now before the Democrats is to translate that excitement - and curiosity - into extra votes. In a region where Mr. Mondale's strategists say they must win some states, even a modest number of extra votes could make a difference in who sits in the White House next year. By choosing to come to the South with Congresswoman Ferraro at his side in his first week of post-convention campaigning, Mondale clearly hopes she can rouse some much-needed additional support for the Democratic ticket.
''I came out of curiosity,'' said Judy Parker, at a noontime outdoor rally here Wednesday that drew a modest-size crowd to the front of the Governor's Mansion. ''There's a lot of people up in those office buildings (overlooking the rally) who wouldn't come down here,'' she said. They are, like her, people who have been supporting Ronald Reagan. But she adds, ''I'm here to listen.''
A few feet away amid the crowd in the street stood Jiny Wood, who also voted for Ronald Reagan in 1980. ''I think Geraldine Ferraro is the greatest thing that's happened to women,'' she said. ''This is our day; this is my day.''
''I'm at the bottom of the ladder; I need help. I need a job, I need money, I need power,'' she said. Before Ferraro's remarks here she said she was still undecided. After the Ferraro speech, she said the same thing. Then she added that she would ''probably'' switch from the Republicans to the Mondale-Ferraro ticket.
But the Ferraro appeal is far from universal here. ''I'm very much against her,'' said Emily Jeenings, also in the crowd. ''She's too liberal.''
And on a grassy knoll beside a church, with a view of the speakers, Frank and Sue Beasley of Alabama said they were Reagan supporters. ''I never liked Mondale ,'' whispered Mrs. Beasley.
When Ferraro walked toward the podium at Mondale's side, the crowd cheered, ''We want Fritz, we want Fritz.'' But an echoing chant grew in strength as the cheering continued: ''Gerry, Gerry.''
''Wow,'' said the vice-presidential candidate after long applause greeted her introduction. ''Do I have to worry about the South?'' she asked. ''No,'' the crowd chanted.
But the answer is, in fact, yes.
Despite some signs that Ferraro is arousing interest in the region, there also is the risk that some Southern Democrats will find the Mondale-Ferraro combination too liberal for their taste.
In Texas, the Democratic duo's next stop, pollster David Hill says Southern white females show the most doubt about women taking part in politics. But, he adds, they also have one of the lowest voter turnout records of any group in the United States. The key, he says, is whether the Republicans can motivate them to vote against Ferraro.
Among the nation's black voters, there is a danger that the attraction of a woman on the ticket might be canceled out in part by lingering resentment over results of the Democratic convention in San Francisco. Black votes are considered crucial to Mondale's chances in the South.
''Whites got Mondale; women got Ferraro; the South got Bert Lance (as general chairman of the Mondale-Ferraro campaign); blacks didn't get nothing at all,'' complained Joseph Delaney of Oxford, Miss. Mr. Delaney was a Jesse Jackson delegate at the state Democratic convention.
Victor McTeer, a black lawyer in Greenville, Miss., and a Jackson delegate to the San Francisco convention, said Mondale might rekindle enthusiasm among black Jackson supporters by adding blacks to his campaign staff, and to Ferraro's staff. And, he said, the Democratic Party should provide campaign financial assistance to Robert Clark, a black running for Congress in Mississippi. (Mondale on Tuesday named US Rep. Charles B. Rangel of New York City, a black, as a cochairman of his campaign.)
Even without such actions, blacks who vote are generally expected to back the Democratic presidential ticket, since most have strong anti-Reagan views. But there is a third alternative.
''We can go with Mondale or go fishing (not vote),'' says Leslie McLemore, a black political scientist at Jackson State University, who was a Jesse Jackson delegate at San Francisco. He adds, ''There's a real danger that a lot of people are going fishing.''
A countersentiment, however, is that blacks may be ''energized'' by Geraldine Ferraro's presence on the ticket, Professor McLemore says. ''The notion is that if a white woman is on the ticket, that not too far in the future a black person will be on the ticket,'' he explains.
''The curiosity factor (about Ferraro) can be translated into votes,'' Mr. McLemore says, but she will have to campaign often and hard ''in the lions' den (the South).''
Despite some liberalizing trends, the South remains fairly conservative. In central Florida, however, two widely disparate types of women are excited about the Ferraro candidacy, says T. Wayne Bailey, a longtime Democratic Party activist in DeLand. One is the conservative, professional woman ''who doesn't need someone to liberate her.'' The other is the more ''passive, traditional'' woman, he says. Among the latter, ''there is a view that this (the Ferraro factor) is not threatening to the traditional role of women.''
''Unless this so-called Ferraro factor goes sour - and it could - this will be the chemistry that could change 1984,'' predicts Dr. Bailey, a political scientist at Stetson University.
Former Mississippi Lt. Gov. Evelyn Gandy says there is ''an air of excitement about her (Ferraro) being on the ticket. I think she'll attract voters to the Democratic ticket who might not (otherwise) vote Democratic.
When one woman breaks a barrier, it helps all women who are interested in fairness.
''I'm hearing that from a lot of women,'' she says.
But Geraldine Ferraro's task in the South is no easy one. And some of that has little to do with her.
Vaughn Galloway, mayor of Pearl, Miss., says, ''I don't think she will do well in Rankin County,'' which is next to the city of Jackson.
Rankin, one of the South's many fast-growing counties, contains many young-to-middle-aged affluent residents. It votes Democratic in local elections and Republican in national elections, says Mayor Galloway.
Sam W. Waggoner, a Mississippi highway commissioner with two decades of experience in politics, says, ''I don't like liberalism.''
President Reagan, he adds, is very popular in the state. So far, Mr. Waggoner says, the Ferraro candidacy has not even been discussed by a church discussion group on public affairs of which he is a member.