Palace boss Dougie Freedman rested a number of key players and Graham Westley’s men seized their chance with Wroe putting them ahead in the second minute.
Akpo Sodje put Preston two up and while Aaron Wilbraham pulled one back, Jeffrey Monakana’s stunning strike restored the home side’s two-goal margin and Wroe sealed the win.
Preston took the lead after just 68 seconds, with Sodje nodding down Monakana’s cross to give unmarked Wroe an easy 12-yard finish.
Sodje bundled home Preston’s second on 18 minutes after Paul Huntington’s powerful header was cleared off the line by Darcy Blake.
Wilbraham’s easy six-yard header from Jonathan Williams’ cross seemed to have put Palace back in the game after 37 minutes, but Monakana hit a wonderful top-corner strike from the left wing just four minutes later to restore Preston’s two-goal lead.