You may need to remove an item from the Moodle gradebook. That item will fall into one of these categories:
A graded Moodle activity that is linked to the course site homepage.
A non-Moodle activity (i.e., a Grade Item) that was manually added to the gradebook.
Moodle activities must be deleted from the course home page in order to remove its connection and appearance in the gradebook. This is a common problem for instructors who inherit sites from other instructors. Once the activity is removed, the corresponding Gradebook column will also disappear.
Items in the gradebook that were added with the Add a Grade Item to the Gradebook feature are not tied to course site activities and can be deleted directly from the Categories and items view (Categories and items in Moodle 2.8).
Removing a Moodle activity from the gradebook
Go to the course homepage and click Turn editing on.
Find the activity you want to remove.
Click the Edit menu to the right of the activity.
Click Yes when asked if you want to delete the activity.
Click Turn editing off. The activity is removed from the course site as well as its corresponding column in the gradebook.
Removing a non-Moodle activity from the gradebook
Go to the course homepage.
Find the Administration block:
Click Gradebook setup (Categories & Items in Moodle 2.8)
Scroll to the row where the item to delete is located:
Click the Edit link in that row
When ask to confirm your choice, choose Yes; click Continue if prompted.
Scroll to the bottom of the Gradebook setup page (Categories & Items page in Moodle 2.8) and click Save changes.