Disabling directory listing is an important. By removing access to the list of files within your directory your making your site more secure, as no one will be able to find loop holes in your software security.
We strongly recommend that you place this line into your .htaccess in the /public_html/ folder:
Options +Indexes
This line will disable the listing of directories for your whole website.
Or another way to do this is upload a blank index.html file inside each folder
