Zeffirelli slammed Muti both for his artistic leadership and for forcing out superintendent Carlo Fontana last week. The dismissal has led to protests and strikes from the theater's staff.
"The problem with Muti is that he wants to be the absolute dictator of La Scala—and he is succeeding," he said "It's unprecedented, unbelievable."
Muti, Zeffirelli said, is "drunk with himself, drugged by his own art and his own personal vanity; he can only talk about himself, he's become a caricature of a conductor." Under Muti's leadership, he added, La Scala has staged "one horrendous production after another: constipated, anal, with no explosion of vitality on stage."
A spokesperson for La Scala, asked for comment, told the Guardian that "Maestro Muti did not intend to reply to Franco Zeffirelli's reiterated and gratuitous accusations."