Piero Gritti, Nicholas Gasperini (2), Mirko Belloni, Marco Scalabrin and Patrick De Villiers all scored tries after the break as the Azzurrini made it four wins in a row against Scotland at U20 level.
Gritti also scored a first-half try, while Scotland’s Euan McVie and Fergus Watson gave them the half-time advantage but were unable to match Italy after the break.
After defeating France 23-20 in Round 3, Italy have won two in a row and will be eyeing a top-half finish if results go their way in Round 5.
The hosts, backed by a raucous crowd, made a fast start in Treviso and scored the first try of the match in just the eighth minute when Gritti muscled over under the posts after a sustained spell of pressure inside the Scotland 22. Martino Pucciarello added the first of six conversions.
Scotland struggled to contain Italy’s powerful ball carriers but they levelled the match just 10 minutes later when McVie charged down a box-kick from scrum-half Mattia Jimenez inside the Italy five-metre line and reached first to pounce on the loose ball and score a try.
With their tails up, Scotland took the lead mid-way through the half. Inside centre Findlay Thomson made a brilliant line-break from midfield, and then found Watson on the wing. The No.11 put his foot down, held off a couple of tackles and managed to ground the ball in the corner. Isaac Coates added his second conversion to make it 14-7.
Scotland held a that lead to half-time but Italy made a strong start to the second half. Gritti scored his second try within 10 minutes when he spotted a gap from the base of the ruck and went through unchallenged to score.
That gave Italy some momentum and they hit the front five minutes later when Gasperini managed to ground the ball from a metre out after a series of phases near the Scotland line.
He mirrored that score in the 59th minute as Italy started to dominate, securing the bonus point in the process. Italy added a fifth try – and fourth in 12 minutes – shortly after as Belloni split two defenders and slid over in the corner.
Scotland stemmed the flow of tries but Italy still managed to score two more before the end, as replacement scrum-half Lorenzo Casilio, just 10 metres out, sent a high kick towards the corner for Scalabrin to leap high, catch and score.
De Villiers then added icing to the cake as a tired Scotland could do little to stop the hosts from turning a scrum in midfield into a try, as they moved the ball wide, made a couple of offloads and released De Villiers to the corner.