The midfielder tapped home from close range to cancel out Freddy Eastwood's early opener for the Shrimpers.
And that earned the Gulls a precious share of the spoils in their fight against relegation and left Southend six points off the play-off places.
Southend were initially on top at Roots Hall and went in front after just nine minutes when Ben Reeves picked out Eastwood on the right flank.
He then cut inside and fired a fine left-footed shot in to the bottom left-hand corner of the net for his first goal since November.
Southend failed to build on the goal though and Torquay started to get back in to the game with Lee Mansell and Jordan Chapell both being denied by Shrimpers goalkeeper Daniel Bentley.
But the visitors equalised in the 45th minute when Chapell's drilled cross picked out Labadie and he tapped the ball home.
The Shrimpers had the better chances during a quiet second half but both Reeves and Kevan Hurst had shots saved by the legs of Michael Poke.