All plants or plant parts of each genus imported for propagation are classified by APHIS-PPQ into one of three risk categories (restricted, postentry or prohibited) based on our ability to detect the regulated pests of that genus in imported plant material.
Restricted plants or plant parts are inspected and treated if necessary for large pests, such as insects, at a port of entry or at an APHIS-PPQ inspection station.
Postentry plants or plant parts are inspected upon entry but must also be grown at an approved site where a state official inspects the growing plants for pests. Both restricted and postentry genera can be imported in commercial quantities.
Prohibited plants or plant parts for propagation are known to carry small plant pathogens or insects that can not be reliably detected by inspection, because the pests are too small, they occur inside the plant tissue, and/or they do not cause consistent symptoms in dormant or growing plants. Prohibited plant material for propagation can only be imported in small quantities through an APHIS-approved quarantine program, unless they originate from an approved source listed in 319.37-5.
What is meant by 'Prohibited genera'?
U.S. Plant Quarantine Programs
Who do I contact to import prohibited plants?
Plant Germplasm Quarantine Program
Information about the screening program for the various prohibited crops tested by the PGQP.
Contacting the PGQP
How does one contact the program managers in order to import material of a prohibited genera?