When Astronema learns that Jakarak can turn anything, including the Power Rangers, into stone; she expresses that she likes that plan a lot. In the next season, Power Rangers Lost Galaxy, the episode Facing the Past, Karone reveals that she was able to turn a warrior she was battling into stone before he was able to use his ultimate weapon against her. The event technically took place before this episode so why she never thought of turning the rangers into stone herself isn't explained. However, it could simply be that the writers haven't thought of that episode yet and overlooked this fact when doing so.