To deadlines, sending emails and submitting stuff in appropriate time.. replying to emails..etc
Is this a new situation, or has he/she been like this for a long time?
If it's new, it may be demotivation, stress, or some other cause (possibly personal circumstances). Try raising it as a discussion point - "We really need to get <x> done to meet deadlines. Is there anything I can do to help / take some of the load?". It might lead to explanations, or at least some insight.
Next step is, I suppose, to take it to a higher level, but I'd be inclined to try to find the cause and work out the problems before resorting to that.
