The 22-year-old from Lima, who won the first ATP title of his career at Hamburg in May, cruised past surprise Wimbledon semi-finalist Fery to win 6-3, 6-2.
The fourth-seeded Buse, currently ranked 36th in the world, sealed victory on his third match point when Fery smacked a backhand long.
France-born Fery enjoyed a fairytale run to the last four at Wimbledon last month before losing to Germany's Alexander Zverev.
The 24-year-old started brightly in Saturday's final in North Carolina as the match went with serve for the first seven games.
But Buse broke in the eighth to make it 5-3 and then held to take the first set.
The South American went a double break up for a 3-0 lead at the start of the second and although Fery clawed one of those breaks back, Buse broke again to take a 5-2 lead before closing out the match.
Both players will now head to New York where they are playing in the US Open first round.