superann

This plugin filters the sitewide comments feed as well as individual post comment feeds.
Upon first-time installation and activation, all trackbacks will be removed from the default WordPress comments feeds. 
You can override this behavior on the options page and also use the comments or trackbacks only feeds described below.
URL for comments only feeds: add the variable “comments” to your feed query string.
<ul>
<li>http://mysite.com/comments/feed/?comments</li>
<li>http://mysite.com/?feed=rss2&withcomments=1&comments</li>
</ul>
URL for trackbacks only feeds: add the variable “trackbacks” to your feed query string.
<ul>
<li>http://mysite.com/comments/feed/?trackbacks</li>
<li>http://mysite.com/?feed=rss2&withcomments=1&trackbacks</li>
</ul>

Separate Feed Comments and Trackbacks

Remove trackbacks from your sitewide and individual post comment feeds, and/or have alternate feeds for comments or trackbacks only.

misteraon

This is a utility plugin that runs database operations on your WordPress database to change settings for and clean up unwanted trackbacks, pingbacks, and comments. Without this plugin you would have to change settings in WordPress and go through all your existing pages and posts and update those as well or have to manually execute SQL commands on your database. Simple Trackback Disabler does this for you…Automagically! It centralizes these functions so you can do what needs to be done all in one place. After you’ve done what you need to do you can simply uninstall the plugin or keep it around so you can do periodic checkups to make sure nothing has changed.
<ul>
<li>It tells you if comments, trackbacks/pingbacks, and the notify other blog settings are enabled in the WordPress settings and allows you to disable them from the plugin page with the press of a button.</li>
<li>It allows you to see how may pages/posts have pingbacks or comments enabled and allows you to disable each type in bulk.</li>
<li>It allows you to delete comments, trackbacks, and pingbacks from the plugin page….even the malformed ones.</li>
<li>You don’t have to manually edit your existing pages and posts individually.</li>
<li>You don’t need to run any SQL statements on your database.</li>
<li>Supports WordPress installations with non-standard database prefixes.</li>
<li>This plugin HAS NOT been tested on WordPress MultiSite. While in theory it should install and work fine when used on individual sites in the Network, there is currently no functionality to support the plugin functions across all the sites in the network at one time.</li>
</ul>

Simple Trackback Disabler

A utility plugin that runs database operations on your WP database to change settings and clean up unwanted trackbacks, pingbacks, and comments.

Separate Feed Comments and Trackbacks vs Simple Trackback Disabler