What you are seeing there is the effect of the option Indexes in the directive Options. As you can see, if there is no index.html file in a directory, Apache2 will show you the contents of that directory. If you don't want the directory contents to be shown, add a file called index.html there with the contents that you do want shown.
Another, more complicated method, is to have the server return an error message when index.html is missing. You could choose specific options for that virtual host to deny browsing of directory contents. Specifically you could add something like the following to your vhost's configuration.
So that would go between the <VirtualHost></VirtualHost> tags.
Note that Location specifies a path relative to the one you see in the browser.