I have not independently been able to confirm this but Hoseheads has posted the two following stories on Manzanita. Manzy's website has not been updated to reflect the stories below.

Manzanita Speedway AZ)I saw a post on my message board today about Manzanita Speedway being sold. I called the the track office and they verified it that the track was sold Wednesday and the last race will be April 11th. An official press release will be sent out soon.3/12


Lucas Oil Studio)Manzanita Speedway, renown as one of the fastest half-mile dirt tracks in the world, will be closing its doors April 11, 2009 after years of legendary racing. The facility has been sold and according to the Speedway the facility will no longer be operating as a race track. Lucas Oil Studios was fortunate enough to do the television production of the final Copper on the Dirt event at Manzanita Speedway and encourages all of its loyal fans to tune in to VERSUS this Sunday, March 15, 2009 - 4:00 PM Eastern to witness racing history (Re-air March 19, 2009 5:00 PM) . The Copper on Dirt classic has been an annual event that showcases the best-of-the-best in open wheel dirt track racing; hosted by Ken Stout with Rob Klepper as color commentator. 3/12

If these stories are true, then that is highly unfortunate.