LOS ANGELES, Jan. 11 – Dep. Dist. Atty. Vincent T. Bugliosi announced his candidacy for Los Angeles district attorney today, declaring incumbent Joseph P. Busch “is not able to run an effective department.”

The 37-year-old Bugliosi, chief prosecutor at the Manson trial, launched his campaign at a news conference at the Greater Los Angeles Press Club.

The challenger is a Democrat. Busch is a Republican. The $40,644-a-year job is nonpartisan.

Bugliosi based his attack on Busch on what he considers ineffective prosecution by the downtown Los Angeles County district attorney’s office.

For the first 11 months of the year, the conviction rate was 48% in felony jury trials, according to court records, Bugliosi said. The year before it was 65%.

Bugliosi called this “by far the lowest of any major district attorney’s office in the entire nation.

“For instance, the conviction rate of the New York district attorney’s office is 81%, Chicago is 79% and San Francisco 72%,” he said.

“Either we are wasting taxpayers’ money by bringing innocent people to trial or we are not properly prosecuting guilty people and are turning criminals loose to commit. new crimes,” he said.

Busch has said that the felony jury conviction rate in the downtown office has dropped, but said that the department’s overall conviction rate — for jury and nonjury court cases — remains high.

Bugliosi, a 1964 UCLA law school graduate, moved into public prominence with his handling of the prosecution of Charles Manson and his followers in the Tate and LaBianca murders — a case which stretched over two years.

Busch, a 20-year veteran of the office, is also a well-known prosecutor. After serving as then Dist. Atty. Evelle J. Younger’s chief deputy, he was appointed district attorney last year when Younger became attorney general.

By BILL BOYARSKY