Treviso is now unbeaten in eight matches across all competitions — winning seven — after putting the Dragons to the sword, scoring nine tries at Stadio di Monigo.
Luca Sperandio and Niccolo Cannone grabbed doubles, while Antonio Rizzi, Ratuva Tavuyara, Giovanni Pettinelli, Monty Ioane and Robert Barbieri also crossed on a chastening afternoon for the Dragons, who have lost four in a row.
Edinburgh dropped to fourth after Cardiff rallied in spectacular fashion in the second half to win 19-17 at Murrayfield.
The Blues were staring back-to-back defeats in the face when they trailed 17-0 after tries from Nathan Fowles and Viliame Mata, but Jason Harries claimed a brace against his former club after Lloyd Williams touched down to stun Richard Cockerill's men.
Meanwhile, Rob Herring scored a first-half hat-trick as rampant Ulster moved up to third with a 54-7 demolition of Zebre.