Hello Mosaik,
Thanks for your question about enabling or disabling the "submit new article" option in your Joomla category list. Unfortunately, after searching for this issue in regards to Joomla 3.x, I didn't find much. I found this post that talks about controlling certain functions using the users. However, I found nothing specific to the Joomla 3.x version regarding the option to enable or disable that query. You may need to find an extension or speak with a Joomla developer for this specific issue. Our apologies that we do not have a direct answer. If you have any further questions or comments, please let us know.
Regards,
Arnel C.