bbPress Protected Forums adds a metabox, shown while editing a forum, that allows you to disable new topic creation for determined user roles.
The plugin is perfect for those situations that you may want your users to see the list of topics of a forum but don’t want them to create new topics.
Plugin fully compatible with bbPress 2.x
bbPress Protected Forums is currently in:
The plugin comes with .po files. Feel free to translate it to your language!
For more information about this plugin you can check the official site.