April 18, 2013, 1:43 PM — Here's how you can delete iOS backups from iTunes.
1. Open the iTunes application.
2. Go to iTunes Preferences.
3. Go to the Devices tab.
4. Select the backup you want to delete.
5. Click the Delete Backup button.
For more, see the original article at the link below.
Delete iPhone & iPad Backups Easily Within iTunes | OS X Daily