what to do after moving wordpress from sub to root

I am developing my first site in a sub dir (ex: http://www.sitename.com/wp) and want to move it to root (using http://codex.wordpress.org/Giving_WordPress_Its_Own_Directory -> Using a pre-existing subdirectory install)

After making the move do I need to block search engines from crawling the “wp” sub directory (I am afraid it will be detected as duplicate content if the directory is crawled)? If I have to block the subdir what are the steps to do it?