This pretty much pins it down. It was taken from here:
http://www.aphis.usda.gov/publications/plant_health/content/printable_version/faq_citrus_fruit.pdf
"Q. Can homeowners ship backyard citrus interstate?
A. Under the final rule, homeowners have the same
opportunity to ship citrus interstate as commercial
producers. Homeowners need to meet the same
requirements as producers, including having their citrus
treated, packed, and inspected at a packinghouse
that has entered a compliance agreement with APHIS.
The citrus must be shipped in an appropriately marked
box."
Ned