The Canadian, a semi-finalist in Melbourne in 2014, had defeated You Xiaodi and Maddison Inglis in the first two rounds of qualifying, but will miss the first Grand Slam of the year for the first time since 2013.
Watch all courts and all matches of the Australian Open live on Eurosport and Eurosport Player
Bouchard had been strong on serve in the first set but succumbed to the pressure when bidding to stay in it at 5-4.
Australian Open
Women's round-up: Bouchard sets up Williams clash with routine win over Peng
15/01/2019 AT 06:19
In the second set, Trevisan threatened to run away with it, racing into a 5-0 lead, but Bouchard launched a mini-comeback, breaking back once to save face and limit the Italian to a 6-4, 6-3 win.

Bouchard falls to world No 154 Trevisan in Australian Open qualifying

Elsewhere in qualifying, Harriet Dart defeated another Italian, Giulia Gatto-Monticone, 6-1, 6-3, granting her a second chance at the Australian Open, following her double bagel loss to Maria Sharapova in last year's tournament.
French Open and Wimbledon doubles champion Barbora Krejcikova is also in the main draw for the first time in her career after beating Varvara Lepchenko 6-4, 6-4.
Shelby Rogers, a former Roland Garros quarter-finalist is also through, having defeated fellow American Caroline Dolehide 6-4, 6-4.
In the men's qualifying draw, Ernests Gulbis headlined the action, with the former French Open semi-finalist winning 7-6, 6-2 against India's Prajnesh Gunneswaran.
Australian Open women
World no.1 Halep makes light work of Bouchard in second round
18/01/2018 AT 08:33
US Open
Women's round-up: Makarova shocks Wozniacki, Rodina ends Bouchard hopes
30/08/2017 AT 16:49