Why dont you just hide Farmville instead? You can keep the friend and not have anything to do with Farmville show up.
Do you know if your way is possible for my iPhone app?
I'm pretty tech ignorant. I've heard of iphones...that's it. Don't know if you can hide stuff on it as well.
Hiding an apps messages is something you do at the facebook level. When you get one of those farmville things hover over it, there will be an X in the upper right corner, click that, you’ll get the option to hide that post, hide all the posts from that user, or hide all the posts from that app. Chose as you wish.