apacite package supports two sorts of citation commands, its own version, or the
natbib versions (loaded with the
natbibapa package option.)
The citation commands support both a pre-note and a post-note. The basic syntax is:
\cite gives you (pre-note Author, Year, post-note),
\citeA gives you pre-note Author (Year, post-note).
So to get your example, you would use:
If you are using the
natbibapa option, the command syntax is slightly different:
yields pre-note Author (year,post-note) while
yields (pre-note Author, Year, post-note).
Since square brackets are used to delimit both the pre-note and the post-note, you need to provide an empty post-note to get a pre-note only. So your example would be:
You can find the full set of citation commands in the
apacite documentation, or for a quick summary see: What is the relationship between natbib, apacite package, and apa document class?.