APHIS (USDA) emailed me the regs that went into effect last May. You can import from Canada and, with some conditions, may be able to import from Costa Rica, Dominican Republic, Guatemala, Mexico, Thailand and may be able to import from China, Netherlands, Taiwan if cuttings are coming from a beetle-free area. But all other countries are prohibited. And you must have an import permit to legally import cuttings.
APHIS is monitoring the transactions from international eBay sellers.
Here is a heading in the regulations which you can search online if you want to find it online:
FEDERAL ORDER
DA-2013-18
May 09, 2013
For the Importation of Host Material of
Anoplophora chinensis, the citrus longhorned beetle, and
Anoplophora glabripennis, Asian longhorned beetle
This Federal Order is effective on May 20, 2013