SAN FRANCISCO, Sept. 15, 2015 /PRNewswire/ -- Diamond Foods, Inc. DMND, +1.29% ("Diamond") announced today that it has entered into a long-term strategic alliance agreement with Walt Disney World Resort and Disneyland Resort tied to its Pop Secret brand premium popcorn. Pop Secret popcorn is now the official popcorn of Walt Disney World Resort in Florida and Disneyland Resort in California.