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SAN JOSE, March 5 (Reuters) - Costa Rica ruling party candidate Johnny Araya is abandoning his campaign to become president of the coffee-producing Central American nation a month before the election goes to a run-off vote, a source close to his camp said on Wednesday.
The source said Araya, of the centrist National Liberation Party, would no longer campaign, although under the constitution his name would remain on the ballot.
The move appeared to guarantee victory for left-leaning former diplomat Luis Guillermo Solis, who emerged as the surprise front-runner in February after polls had shown him in fourth place.
"What is going to happen is that he is not going to campaign any more," said the source, who spoke on condition of anonymity ahead of a planned announcement by Araya.
Araya, previously the favorite to win, has been beset by voter resentment over government corruption scandals under President Laura Chinchilla and rising inequality.
A former mayor of San Jose, Araya has faced criticism from equality-conscious voters for gaffes like underestimating the price of milk in an interview.
The national prosecutor's probe of allegations of abuse of authority and embezzlement have also dampened his appeal, after Chinchilla sparked outrage by accepting flights on a private jet despite laws barring public officials from accepting sizable gifts.
A University of Costa Rica survey published late on Tuesday showed Araya trailed center-left rival Solis 20.9 percent to 64.4 percent ahead of the April 6 run-off.
The lead marks a dramatic upswing for Solis, who won 30.64 percent of the ballot last month ahead of Araya, who garnered 29.71 percent.
Neither of the candidates reached the minimum 40 percent plus one vote threshold needed to avoid a second round run-off.
Tuesday's poll surveyed 1,200 Costa Rican adults with a 2.83 percentage point margin of error. (Reporting by Alexandra Alper and Zach Dyer; Editing by Dan Grebler)