It is nearly impossible to listen to popular radio stations in Central Florida without hearing candidate ads.

ALTAMONTE SPRINGS, Fla. — If President Obama’s campaign believes, as he told The Des Moines Register last week, that it will be Latinos who help tip the election in his favor, the Mitt Romney campaign is trying its best to persuade Latinos to vote another way.

It is nearly impossible to listen to popular radio stations in Central Florida without hearing candidate ads.

Though conventional wisdom says Cuban Americans in Florida will go for Romney and Puerto Ricans and other Latinos favor Obama, the proliferation of radio messages indicates that both campaigns believe the Latino vote is not necessarily locked up.

A poll by Florida International University, El Nuevo Herald and The Miami Herald found that Obama leads Romney 51 percent to 44 percent among Latinos statewide, a much smaller edge than Obama has among Latinos in the country as a whole.

Among Puerto Ricans in Florida, who traditionally lean Democratic and make up a big percentage of the population in the Orlando area, 61 percent said they’d support Obama, compared with 70 percent nationally.

One study found that voter turnout jumped by 4 percentage points in Spanish-speaking areas that received get-out-the-vote messages over radio, compared with areas not exposed to them, said Costas Panagopoulos, a Fordham University professor who has studied radio outreach to Latinos.

In the statewide poll, 51 percent of Latinos in Florida said they thought Obama had not fulfilled his promises to the Latino community, compared with 38 percent polled nationwide who felt that way.

Aside from radio ads, the Romney campaign has employed bilingual phone banks and door-to-door canvassing. Surrogates such as former Gov. Jeb Bush, Sen. Marco Rubio and Cuban-American politicians and brothers Lincoln and Mario Diaz-Balart have appeared on television and radio programs as the campaign also runs ads.

Jim Jimenez, one of the Republicans appearing on a radio show on Romney’s behalf, says he thinks Puerto Rican voters, while traditionally Democrats, are open-minded.

“The idea is to bring balance, and balance makes people think things over,” he said. “And I really think the issue of the economy is resonating.”

The Romney campaign is outspending Obama 15-to-1 at WONQ-AM, said station manager Manny Arroyo.

Obama has outspent Romney in Spanish-language radio in the Miami, Orlando and Tampa areas this month, according to Media Monitors, which tracks radio and TV ads.

His campaign also has been on the ground in Florida for a long time. Democrats also have a registration advantage: Republicans led among Florida Latinos by 25,000 in 2008, but now trail Democrats by 112,000.