The 36-year-old former England international broke his duck in the 35th minute, opening the scoring with a hooked volley at the far post following a Josh Mitchell flick-on.
Heskey almost doubled his tally 11 seconds after half time when he latched on to a clever reverse pass from Joel Griffiths before hitting a goalbound shot that was deflected wide by busy goalkeeper Glen Moss.
Moss was beaten from the resultant corner, as Griffiths found the net with a fierce half-volley.
It was 3-0 just before the hour mark. Zenon Caravella cut in from the right and floated in a cross for Adam Taggart, who headed home from eight yards.
Taggart found the net again 13 minutes from full time, beating Moss with a heavily-deflected shot from just inside the penalty area.