According to the article published in link

We knew that one fallout of the shocking 5 year leap on Desperate Housewives would be the loss of or recasting of certain characters on the show.

It seems that one of these instances will be with Susan's daughter Julie, played by Andrea Bowen.

Bowen first thought that she might have to cut her hair or something, in an attempt to look older; she was completely surprised when she learned that her character was being removed from the show entirely. Teri Hatcher - who plays her TV mother Susan - was really upset about this news and has said, "This is a totally producer/network decision that I have nothing to do with, and I guess I can go out on a limb and say I don't support."

Says Marc Cherry, the show's creator, "We'll have her back at some point. Maybe when she's older, who knows? She might get married and become a desperate housewife on the Lane." But for now...will you guys miss Julie or do you think her story has played out??

I guess we will have to wait for the beginning of Season 05 and see who is in and who is out...but if Hatcher and Cherry confirmed Andrea is no longer in the show and assured it isn't their fault, we will have to believe them..it would be a real pitty to feel Julie's absence in Wisteria Lane.

"I WILL MISS YOU ANDREA"