Villavicencio's Build party, or Construye in Spanish, announced on social media it had tapped Andrea Gonzalez to replace the slain 59-year-old as its presidential candidate in the Aug. 20 vote.
Villavicencio, an ex-lawmaker and journalist with a long track record of exposing corruption, was gunned down last week after leaving a campaign event in the capital Quito despite his own government-provided security detail.
Six suspects - all Colombian nationals whom police accuse of links to criminal groups - have been charged with the murder and remain in custody after a judge on Thursday ordered they remain behind bars as the investigation into the crime continues.
His replacement, Gonzalez, is an environmental activist who has not previously held public office. She had been selected by Villavicencio to be his running made in the snap election called by outgoing President Guillermo Lasso.
While ballots have already been printed, by law votes for Villvicencio will automatically transfer to Gonzalez.
The South American nation of some 18 million has seen a rising tide of violence in recent years, including a sharp increase in the murder rate.
Villavicencio had been polling around the middle of the pack in a field of eight candidates prior to his assassination.
Beyond security, employment and migration have emerged as major campaign issues.
(Reporting by Alexandra Valencia; Writing by David Alire Garcia; Editing by Sandra Maler)
