John M. Couric, father of Katie Couric, has died. He was 90.Couric’s son, John M. Couric Jr., said Thursday night that his father died Wednesday at Virginia Hospital Center in Arlington of complications from Parkinson’s disease. Services will be private. The elder Couric, a Georgia native, retired in 1985 as a writer with the U.S. Food and Drug Administration. He started his career as a reporter for the Atlanta Constitution and United Press before going into public relations work in 1957.