Wordpress appending /feed to pages and google indexing them

[leporello]

I've recently found what seems to be a major problem on one of my sites. Every page on the site (2-300) has an extra page with the same url but with feed at the end.

eg. mysite.com/article-1/feed , mysite.com/article-2/feed

In my robots file i have the following 2 lines:

Disallow: /feed
Disallow: */feed

However, all those rubbish pages are indexed in Google.

Does anyone know why/how this is happening and how to prevent it? I've been manually removing them via GWT for the last few days.

Thanks guys.

[Mr-AJ]

I'm also interested in this one. I only saw it on a couple of posts but not on every one. In my case only posts are affected and not pages.
Maybe there's a plugin that submites feed URLs automatically with the intention to get posts indexed faster?