He is survived by two sons and four daughters, family sources said.
Appa Rao had been undergoing treatment for a spine related ailment for the past six months.
Besides Ramakrishnudu, state Deputy Chief Minister N Chinarajappa, East Godavari District Collector Neetu Prasad, MLAs and other party activists paid their last respects.
The last rites were performed at Rao's native village in Thondagi Mandal in the presence of Ramakrishnudu.