Wilco, Jamey Johnson, Phosphorescent and Jason Mraz are the latest additions to Farm Aids 2009 lineup. These four acts join festival mainstays Willie Nelson, Neil Young, John Mellencamp and Dave Matthews. As previously reported, the event will take place October 4 at St. Louis Verizon Wireless Amphitheater. Several additional acts will be added to the benefits lineup in the coming weeks.