Block Spam from my WordPress Blog by turning off trackback

My blog has been inundated with spam, I do not want to block valid comments only the spammers. The trackback option is enabled and this allows spammers to post comments without registering a valid email address. Turning off trackback or ping back would prevent this, I have known about this for a while but have been too lazy to get around applying the fix. But I finally applied the fix by turning off trackback, with this command in MySql, UPDATE wp_posts SET ping_status="closed".
Below is what I cut and pasted from the WordPress FAQ. I did not write it, simply cut and pasted it.

I have disabled comments, but comments continue to be posted

If you have unchecked Allow people to post comments on the article on the Options > Discussion panel, then you have only disabled comments on future posts. To completely disable comments, you will have to edit each past post and uncheck Allow Comments from the Write Post SubPanel. Alternatively, you could delete the wp-comments-post.php file, or run this MySQL query, from the command line on a shell account, or using phpMyAdmin: UPDATE wp_posts SET comment_status="closed";

I have disabled trackbacks, but trackbacks continue to be posted

If you have unchecked Allow link notifications from other Weblogs (pingbacks and trackbacks.) on the Options > Discussion panel, then you have only disabled trackbacks on future posts. To completely disable trackbacks, you will have to edit each past post and uncheck Allow Pings from the Write Post SubPanel. Alternatively, you could just simply delete the wp-trackback.php file, or run this MySQL query, from the command line on a shell account, or using PHPMyAdmin: UPDATE wp_posts SET ping_status="closed";