Pineapples are in a special class, not restricted, as Carol said.
Here's the APHIS list:
http://www.aphis.usda.gov/lpa/pubs/fshee...awaii.html
Permitted Items from Hawaii into the U.S. Mainland and Guam (after passing inspection):
Beach sand
Coconuts
Cooked foods
Dried seeds
Dried decorative arrangements
Fresh flowers (except gardenia, jade vine, and Mauna Loa)
Hinahina (Spanish moss)
“Irish” or white potatoes
Pineapples
Rocks or stones
Seashells (except land snail shells)
Wood (including drift wood and sticks)
Note: Papayas require treatments before they can be shipped to the U.S. mainland. Commercially canned and thoroughly cooked foods are permitted.
Items from Hawaii Not Permitted into the U.S. Mainland:
Berries of any kind, including coffee berries and sea grapes
Cactus plants or parts
Cotton and cotton bolls
Fresh flowers of gardenia, jade vine, and Mauna Loa
Fresh pulpy fruits and vegetables (except pineapple)
Kikania and fresh pandanus
Live insects and snails
Plants in soil
Seeds with pulp and fresh seed pods
Soil
Sugarcane
Swamp cabbage (unchoy)
Sweet potato (raw)