In order to delete a team there must be no other team members other than the team captain. If there are other team members, you will to move them to another team or make them individual participants. For instructions on how to do so, please see here first. 

How to get there:

Login to the Wizathon back end system.

Click on the "Teams" tab.

What to do:

Locate the team name and click on the pencil icon, "edit".

Click on the "Change/Leave Team" button from the menu on top, second from the left..

If the team captain is joining another team, click the team's name and then click "Save Team".

If the team captain is becoming an individual, click "Remove From Team"..

If the team captain is starting a new team, click "Create New Team".

Finally, click "Save My New Team Selection".

At that point, the team will automatically be deleted, since there are no members or captain, and all sponsorships for that team will move to the team captain if he chose to become an individual or to the team if he switched to.