Wilson could have restored the three-goal advantage in final seconds, but he pulled his shot wide from a favourable position.
United, the current holders, will now meet Manchester City in the final at L.F.A. County Ground, Leyland, before the start of next season.
United: Johnstone; Hendrie, McCullough, Blackett, James (Love 74); Grimshaw, Weir (Wilson 69), Pearson (A Pereira 69), Daehli; van Velzen, Lawrence. Subs not used: Sutherland, Rudge.