Bruce' side have hit a serious dry spell - notching just two goals in seven games, their last three matches have all resulted in goalless draws.
Their lack of options has not helped, with Heskey leaving the club in January and his replacement Mido struggling with injury problems.
Egyptian forward Amr Zaki has not scored since December after a promising start in the Premier League, whilst Hugo Rodallega is still adapting to English football.
Few optionsWith Wilson Palacios leaving for Spurs and Antonio Valencia injured, the Latics boss admits he has little in the way of options but insists the goals will come soon.
"We have lost Heskey, Palacios and Valencia and of course Zaki - who started the season so well - has dried up a bit," said Bruce.
"Emile and Wilson gave us something going forward and I do believe we have lost that cutting edge.
"It is one area where I always say it is the most difficult part of the club, the top end of the pitch.
"We have brought in two or three players who we think will add to that - Charles N'Zogbia, Rodallega, Mido - and so we hope we will be okay on that.
"But it would be more of a concern if we couldn't keep a clean sheet at the other end."
DefenceWigan have built their league position on defence this term, conceding just three goals in eight league games, albeit that six of those have resulted in a draw.
"We have hung in there and the resilience of the squad is still there," he added.
"A manager wants his best players on the pitch and quickly - especially when you have paid big money for them - but we are going to have to be patient.
"We are limited at the moment but we've got to the end of February and I can't complain.
"We've had a good run in that respect. It is always disappointing when you lose people through injury but it is part of it."