Paul Jewell`s side were on top throughout and deserved the three points which leaves Scunthorpe staring at a return to League One.
Caretaker boss Tony Daws took charge of the visitors for the first time after Ian Baraclough was sacked in the aftermath of the 3-0 home defeat to Preston in midweek but saw his charges fail to threaten as they were passed off the Portman Road pitch.
Edwards whistled in a 30-yard drive before the break and the victory was assured by a trademark Bullard free-kick early in the second half.
Scunthorpe are now four points adrift of safety and have just eight games left to preserve their Championship status.
Source: PA
Source: PA