Trackback / Pingback feature of WordPress may not be suitable for many blogs. If you receive too much spam related with this trackback and pingback or if you receive too much trackback/ pingback URL errors in Google Webmaster Tools, it is better to disable this feature of WordPress.
Goto Settings-Discussion and uncheck “Allow link notifications from other blogs (pingbacks and trackbacks)”
This will prevent trackback and pingback for all future posts. Now you need to disable the same for existing posts. For that purpose you should run SQL statement as follows:
UPDATE wp_posts SET ping_status='closed' WHERE post_status = 'publish' AND post_type = 'post';
UPDATE wp_posts SET ping_status='closed' WHERE post_status = 'publish' AND post_type = 'page';