The visitors batted first at Edgbaston and had Stevens top score with 69 in a total of 176-6 in twenty overs.
Warwicks had Darren Maddy back in the side and he was one of the wicket takers.
The Bears started well getting to 40-1 in six overs but their run rate slowed and wickets of Trott (13),Troughton (22),Maddy (27) and Ant Botha (35) saw them close on 133-8 and a 42 run defeat.
Tomorrow,Warwicks play Bangladesh A in a tour match at Edgbaston and they have called Leamington wicketkeeper Michael Balac into the squad.
Andrew Miller could also make his Warwicks debut in the match which will see the return of Lee Daggett.
In the test match at Lords, Coventrian Ian Bell was 75 not out as England closed on 309-3 on the opening day of the first test against South Africa. Kevin Pietersen was 104 not out.