The home side had the better of the chances but failed to break Exeter down and ultimately paid the penalty.
Rovers started the better and in the 20th minute Damon Searle was unlucky with a powerful shot.
Exeter keeper Martin Rice produced a wonderful fingertip save to deny Searle to keep the scoreline at 0-0.
Exeter's first chance of the first half came in the 29th minute when Andy Taylor brought a sharp stop from Forest Green's Ryan Clarke.
Two minutes later Michael Brough fired wired for Rovers as they sought to break the deadlcok, before Mark Beesley forced Rice to make a brave block five minutres before the interval.
Exeter started the better after the restart and Dan Woodards was unlucky with a shop that was blocked.
In the 54th minute Woodards had another good chance but fired over from distance.
In the 56th minute Beesley had an excellent chance, but his shot was blocked as Rovers failed to find the back of the net.
Shortly after the hour mark Billy Jones fired high and wide for Exeter and in the 74th minute Jones was unlucky with a rasping drive which flews inches wide of the target.
At the other end Guy Madjo saw a shot blocked, before Jones fired over with three minutes remaing.
That was as good as it got and Rovers, rooted to the foot of the table, missed the chance to ease their relegation worries.
They are still two points adrift of the safety margin with Scarborough and Southport languishing near the foot of the table with them.