Phytosanitary and Regulatory Issues in the Movement of Plant Genetic Resources: A U.S. Perspective

Karen A. Williams and Gary Kinard

Corresponding author:

The purpose of this chapter is to provide an overview of regulatory considerations in the U.S. when importing or exporting germplasm.


  1. Introduction
    1. Overview
    2. Definitions and regulatory organizations
  2. Importing germplasm into the United States
    1. Introduction
    2. Plants for planting manual
    3. Import permits
    4. Phytosanitary certificates for importing germplasm
    5. Inspections of imported plant material
    6. Quarantine of imported prohibited genera
    7. Preparation of plant material for export to the United States
  3. Exporting germplasm in the United States
    1. Introduction
    2. Import permits from recipient countries
    3. Phytosanitary certificates for exporting germplasm
    4. Phytosanitary Certificate Issuance and Tracking System (PCIT)
  4. Movement of threatened and endangered plant material
  5. Conclusion
  6. Additional Information
  7. Acknowledgments

1. Introduction

1.1 Overview

Introduction of exotic (non-native) plants has played a vital role in agricultural and horticultural development in every country in the world. It remains essential to import new plant material for plant breeding and research, enhancement of collections in plant genebanks, and other purposes. Regulating imported plant material minimizes the risks of also introducing species that may be harmful to local agriculture, forestry, industry or the natural environment. Exotic species designated as plant pests may cause or transmit diseases, displace native plant species, and diminish the economic or aesthetic value of a product or the environment. These unintentionally introduced exotic species may include insects and other arthropods, microorganisms, and other plants. Citrus greening disease, Dutch elm fungus, chestnut blight fungus, citrus canker bacterium, plum pox virus, European corn and Emerald Ash borers, Japanese beetle, brown marmorated stink bug, fire ant, purple loosestrife and cheatgrass are just a few examples of pests that have caused severe damage and economic losses in the U.S. after being introduced and becoming established. Conversely, grape phylloxera is an insect that originated in North America and was spread with plant material to become a threat to grapevine cultivation worldwide.

This introductory eBook chapter, phytosanitary issues in germplasm movement, is written for genebank employee training and as a teaching resource for college courses. It is an overview of the factors to be considered when importing and exporting germplasm, but does not provide extensive detail nor should it serve as a checklist guide. It focuses on U.S. applications, but also notes there are international authorities that aim to minimize global risk when germplasm is exchanged. Regulatory guidelines are vital in genebank management, where the receipt and distribution of plant material are an inherent and critical components of the genebank mission.

Upon completion of this eBook chapter, learners will be able to:

  • Describe the importance of regulatory oversight when importing and exporting germplasm.
  • Describe the basic documentation requirements when importing and exporting plant genetic resources.
  • Identify the regulatory authorities in the U.S. that issue permits and conduct inspections needed for the movement of plant genetic resources, based on the type of plant material.

1.2 Definitions and Regulatory Organizations

The term “phytosanitary” relates to plant health conditions, especially in agricultural crops as it relates to trade and commerce.


Figure 1. The emerald ash borer (Agrilus planipennis), was first identified in the U.S. in 2002 (left). It causes severe damage to ash trees, such as the green ash (Fraxinus pennslyvanica) shown here (right). Photo credit: USDA.


Figure 2. Citrus canker caused by the bacterium Xanthomonas axonopodis pv. citri was introduced to the U.S. in the early 1900s. Shown here is damage to immature citrus fruit. Photo credit: USDA-APHIS.


Figure 3. Cheatgrass (Bromus tectorum), introduced in the late 1800s, is an aggressive weed, especially in the western U.S., where it outcompetes native grasses and forbs. Photo credit: Bureau of Land Management.


Each country’s National Plant Protection Organization (NPPO) is usually responsible for enforcing regulations on importing foreign plant material. The NPPO in the U.S. is the United States Department of Agriculture Animal and Plant Health Inspection Service (APHIS); specifically, their Plant Protection and Quarantine (PPQ) programs. The NPPOs in some countries have formed regional or hemispheric alliances to discuss phytosanitary issues and develop common standards that balance the requirements of trade with the need to protect plant and ecosystem health. In 1976, the United States, Canada, and Mexico formed the North American Plant Protection Organization, which is now recognized by the three countries as the authority for setting phytosanitary standards in the three countries. The International Plant Protection Convention (IPPC) governs the setting of phytosanitary standards at the international level.

The IPPC is a multilateral treaty under the auspices of the Food and Agriculture Organization (FAO) of the United Nations. There are currently 184 countries as contracting parties to the treaty, which entered into force in 1951. The IPCC is recognized by the World Trade Organization (WTO) as the sole organization with authority to set international phytosanitary standards.

2. Importing germplasm into the united states

2.1 Introduction

The first phytosanitary and quarantine import regulations were enacted in the U.S. with the passage of the Plant Quarantine Act (PQA) in 1912. The Plant Protection Act (PPA) of 2000 consolidated the PQA and other legislation related to plant pests and noxious weeds into a single statute. This legislation also adopted using the single word “pest” in regulations to describe the entire range of organisms and infectious agents that can adversely affect plant health, including insects, noxious weeds, invertebrates, protozoans, and microorganisms such a bacteria, fungi, and viruses. The PPA gives the Secretary of Agriculture the authority to reduce the risk of introducing these pests by restricting importation of specific plants. Based on that authority, APHIS-PPQ developed regulations on the importation of commodities (such as fruits and vegetables), whole plants, plant products, and plant propagation materials that might harbor pests. These regulations protect against the entry, establishment, and spread of pests that could threaten U.S. agriculture and natural resources. The regulations are enforced by federal agents at seaports, borders, and airports where they intercept restricted items such as food carried by tourists, and detect known pests that contaminate commodities, packing materials, and shipping containers. APHIS agents also inspect plant materials (seeds, whole plants, cuttings, etc.) that are imported for planting (Plants for Planting), which includes material for research and germplasm curation.

The complete U.S. regulations related to plant protection and quarantine administered by APHIS are found in the Code of Federal Regulations (CFR), Title 7, Parts 300 – 399

For many years, regulations on specific plants and pests were published in the Code of Federal Regulations (CFR 319.37). However, this became unwieldy due to both the increasing number of regulations and the lengthy process required to modify the CFR. In 2009, APHIS proposed publishing the regulatory actions under a new authority called Not Authorized Pending Pest Risk Analysis (NAPPRA). This action was finalized in 2011 with a statute in CFR 319-37-4. Taxa of plants on NAPPRA lists cannot be legally imported to the U.S. until a Pest Risk Analysis (PRA) is completed, except through the various inspection and/or permitting routes described in the sections below. The PRAs are formal studies conducted by APHIS to evaluate the threat a plant and/or pest poses to agriculture and ecosystems in the U.S., and where possible devise strategies to mitigate significant risks and allow importation of the taxa.

The plants and pests covered by NAPPRA are listed in a publicly available manual, Plants for Planting, published by APHIS (see details in the section below). APHIS announces changes to the NAPPRA lists through the Federal Register. A public comment period, typically 60 calendar days, is required before the actions can be finalized. Two separate NAPPRA lists are maintained:

  1. Quarantine Pest Plants – these are plants that themselves pose threats, typically for their potential to become invasive and/or weedy.
  2. Hosts of Quarantine Pests – these are the plants that host quarantine pests. This list specifies the quarantine pest that is regulated as well as its host plant.

To date, two lists have been finalized for both quarantine pest plants and hosts of quarantine pests (in 2013 and 2017). As of this writing, a third round of NAPPRA updates proposed in November 2019 awaits finalization. The NAPPRA lists, even at the proposal stage, include publicly available data sheets summarizing the scientific information that justifies the regulatory action.

2.2 Plants for Planting Manual

Restrictions on importing propagative plant material into the U.S. are listed in the Plants for Planting manual (download here). This manual covers all imported regulated plants and plant parts that are capable of propagation, including buds, bulbs, corms, cuttings, layers, pollen, scions, seeds, tissue, tubers, and similar structures (i.e., any type of germplasm). Plant nucleic acids are not currently regulated as propagative material. The manual includes general requirements, requirements and restrictions for specific taxa, requirements for plants to be entered in quarantine and post quarantine programs, and information on importing and exporting plants for planting that are protected by the Convention on International Trade in Endangered Species of Wild Fauna and Flora (CITES), the Endangered Species Act (ESA), or both (see section IV of this eBook chapter for more informative on CITES and ESA). Note: There are separate supplemental manuals with additional regulations (import and export) prepared for non-continental U.S. state and territorial islands.

The following are all attributes or conditions that can be regulated when importing plant propagative material to the U.S.:

  • taxon of plant
  • plant part
  • country (or more specific within country location) from which entry is restricted
  • taxa specific restrictions and requirements

2.3 Import permits

APHIS-PPQ import permits are required for much of the plant material entering the U.S. Applications may be submitted online using the ePermits system or printed and submitted by mail. Information on applying for permits may be found on the APHIS website.

There are several types of import permits, all of which are provided by APHIS free of charge. The type of permit required depends on the plants being imported and the federal regulations covering the plants. Each type of permit specifically indicates the plants and plant parts that it covers and the special handling procedures required after receipt and inspection of these materials. The specific restrictions requiring a special import permit are listed for each plant in Table 6.2 in the Plants for Planting manual.

Some of the APHIS permits that are relevant to importing germplasm are:

Post-entry Quarantine Permit. The post-entry quarantine (PEQ) permit applies to plant material that must be inspected by state regulatory officials after entering the U.S. to ensure that it complies with phytosanitary and import regulations of both authorities. The length of the post-entry quarantine period is usually two years. Seeds are exempt from post-entry quarantine. Post-entry quarantine must be conducted in a state that has a State Post-entry Quarantine Agreement with APHIS. PEQ is used by nurserymen, botanic gardens/arboreta, and clonal germplasm repositories. Plants that require post-entry quarantine are listed in Table 5-2 in the Plants for Planting manual.

Controlled Import Permit. The controlled import permit applies to regulated plants whose importation is not authorized under NAPPRA or is prohibited for other reasons. The allowed uses of plants imported under this permit are limited to experimental, therapeutic, or developmental purposes. The recipient of a plant authorized for propagation under this type of permit must have access to a facility adequate for containing any potential pests associated with growing the applicable plant.

Federal Noxious Weed Permit. Taxa that are designated as noxious weeds have been determined by the federal government to be detrimental to U.S. agriculture. They are prohibited from entry into the U.S. from all countries unless a permit has been issued. A federal noxious weed permit applies to maintenance/transportation of seeds/plants of these taxa. Many states also have established additional weed regulations and permitting requirements, usually enforced by an agricultural or environmental department within the state.

 Protected Plant Permit. This permit is applicable to importing plants protected under the Convention for International Trade in Endangered Species of Wild Fauna and Flora (CITES) or the United States Endangered Species Act (ESA). See section IV of this chapter for more information.

Permit for Small Lots of Seeds without a Phytosanitary Certificate. APHIS issues permits for importation of small quantities of seeds without the need for securing a phytosanitary certificate. The permits allow importation of lots with 50 seeds or 10 grams of seed of 1 taxon per packet; and a maximum of 50 seed packets per shipment. The complete requirements for this type of permit and instructions on applying for it are found on the APHIS web site.

2.4 Phytosanitary permits for importing germplasm

Phytosanitary certificates (see: Example of Phytosanitary Certificate) provide health inspection documentation for plants and plant products being shipped to another country. They certify that the material meets the importation requirements of the recipient county. This typically includes inferences that the material is pest-free based on, singly or in combination, growing conditions, visual inspection, or testing. In the U.S., phytosanitary certificates are issued by APHIS, but can also be issued by approved inspectors from state departments of agriculture.

Original phytosanitary certificates are required for most plants and plant parts entering the U.S. for planting. They must conform to specific regulations, including being patterned after the model certificate designed by the International Plant Protection Convention (described in the Introduction). A phytosanitary certificate must be issued by the NPPO of the country of origin. Other requirements for these certificates are found in the Plants for Planting manual. Without the original phytosanitary certificate, APHIS will refuse entry of materials at the port of entry or inspection station. Materials entering under a Controlled Import Permit or a Small Lots of Seed Permit are exempt from the requirement for phytosanitary certificates because they are covered under other regulations.

2.5 Inspections of imported plant material

All plant materials, even those not regulated as restricted or prohibited, entering the U.S. must be inspected by APHIS. The inspection aims to ensure that the materials are free from exotic pests, pathogens, noxious weeds, soil and extraneous materials.

Regulations require that most imported plants and seeds be sent to plant inspection stations operated by the APHIS-PPQ. Specialists examine the plants and/or seeds to ensure that they do not harbor pests that are not known to occur in the U.S. and to ensure that they comply with federal regulations on importing. APHIS-PPQ currently maintains 16 plant inspection stations at or near major ports of entry. In addition, PPQ operates a National Plant Germplasm Inspection Station at the National Plant Germplasm Quarantine Center (NPGQC) in Beltsville, Maryland. The NPGQC at Beltsville emphasizes inspecting and testing germplasm intended for use in plant breeding and other research programs.

The PPQ officers at the APHIS Inspection Stations also enforce regulations that apply to the import, export and re-export of plant species protected by the Endangered Species Act and the Convention on International Trade in Endangered Species of Wild Fauna and Flora (CITES).

2.6 Quarantine of imported genera

Some plant material imported to the U.S. requires a period of quarantine and diagnostic testing, in addition to the inspection process. Such additional safeguards are to exclude pests whose absence cannot easily be inferred by visual inspection or observations, such as viruses and other obligate parasite pathogens for which signs and symptoms of infection might not be apparent without testing. Plant material that requires quarantine is referred to as Prohibited Genera. Included among Prohibited Genera are the germplasm of many clonally propagated crops such as fruits (tree, small, and vine), potatoes and sweet potatoes, sugarcane, rice and other grasses, and some trees and shrubs. The plant parts that are prohibited vary by taxa and can include vegetative propagative material, seeds, or both. The Plants for Planting manual documents the regulations for Prohibited Genera material. Once the plant material has received the import inspection, it is transferred to an APHIS operated or approved quarantine program for the required testing. These facilities have enhanced containment and advanced diagnostic capabilities needed for quarantine. The material might be tested by a range of methods for target pests including biological, serological, and molecular assays. The recent trend has been to adopt increasingly nucleic acid amplification (e.g. PCR) and high throughput sequencing detection assays to increase the sensitivity and reliability of the testing, as well as potentially shorten the quarantine period. Some quarantine programs offer therapy options if material is infected. Once the plant material is determined to be free of target pests it can be released from quarantine to the recipient and further propagated and distributed without federal restrictions other than any that apply exclusive of the prohibited status (e.g. CITES, noxious weed, genetically-engineered, state regulated). Some programs also offer a provisional release from quarantine, based on preliminary negative pathogen test results, while additional testing is ongoing. Provisional releases require additional safeguarding restrictions from the recipient, but can be especially beneficial to researchers by enabling expedited access to the material while quarantine testing is completed.

2.7 Preparation of plant material for export to the United States

Careful preparation increases the likelihood that plant material sent from another country to the U.S. complies with regulations and can be processed successfully by APHIS-PPQ. Cooperators shipping material to the U.S. should follow these guidelines:

  • Carefully clean all plant material. The plant material must be free of soil and must not be established in growing media except as indicated in the General Restrictions chapter in the Plants for Planting manual.
  • When shipping plants or cuttings, ensure that material is within the size-age range limitations presented in the General Restrictions chapter in the Plants for Planting manual. Incorporate approved packing materials.
  • Make sure the individual packets for all accessions are clearly labeled with scientific names.
  • Group germplasm requiring special permits in separate packages from non-permit material. Also, group bulbs, corms, cuttings, plants, etc. in separate packages from the seed packets.
  • Carefully seal all accession packets to prevent mixing during shipment.
  • Place a copy of the plant material list and the original Phytosanitary Certificate and Import Permit inside one of the packages of plant material.

Additional details on importing plants into the U.S. may be found in the Plant Importer’s Responsibilities, APHIS PPQ Circular Q.37-2 (download here). This stand-alone document is a useful overview of the U.S. importation requirements for any plant material.

3. Exporting germplasm from the United States

3.1 Introduction

It is a common misconception that the U.S. government regulates the export of plants and plant products to other countries. This is true only for material covered by ESA/CITES regulations discussed below in section IV. USDA-APHIS does not require entities in the U.S. to obtain a phytosanitary certificate to ship plant material to other countries; the burden for compliance with phytosanitary regulations always resides with the foreign importer or recipient. However, APHIS and authorized state agencies in the U.S. perform agricultural inspections as a service (usually fee-based) to facilitate the safe movement and international exchange of plant material, including germplasm. After ascertaining that the phytosanitary condition of the germplasm meets the import requirements of the foreign country, the phytosanitary certificate is issued. APHIS-PPQ certificates are internationally recognized and accepted under the terms of the IPPC. All U.S. phytosanitary certificates are currently printed and packaged with shipments, although there are international efforts underway to implement a common platform, paperless, digital format for exchanging them.

APHIS Plant Health Export Information

The primary source for online information about export programs is the APHIS-PPQ Plant Health Export Information page, which contains:

  • links to export certification forms
  • state contacts for export certification
  • information about user fees
  • FAQs

The most detailed content on this page is the Export Program Manual (download here) which provides extensive documentation about the process for obtaining export certification for various categories of plants and plant products. Export certification attempts to document compliance with the foreign/importing country’s phytosanitary requirements, which vary based on the taxa and plant parts just as in the U.S.

3.2 Import permits from recipient countries

Any country that is a party to the IPPC is required to provide an import permit to those requesting foreign plant material. The import permit specifies the plant health conditions that must be met for the material to legally enter that country. The form itself varies by country, but all must contain a clear indication that it is an official import permit issued by the NPPO, a unique and traceable identifying number, an expiration date for the permit, and the signature of an appropriate NPPO official. Import permits contain general conditions on the phytosanitary certificate that must be stated as having been met and can also include requirements designed to help that country exclude specific, stated pests. These are often called Additional Declarations and can even include precise testing or observational requirements or treatments that must be documented on the phytosanitary certificate before the material leaves the U.S. The germplasm recipient is responsible for supplying, electronically or by paper, an import permit obtained from their NPPO.

3.3 Phytosanitary certificates for exporting germplasm

Exporting germplasm from the U.S. usually involves obtaining an inspection and phytosanitary certificate from APHIS through PPQ Form 577, which is used for live, domestic plant material. There are separate forms for processed plant material (PPQ 578), and for material that is transiently passing through the U.S. and is being re-exported or is of blended domestic and foreign origin (PPQ 579). Both the original import permit and U.S. issued phytosanitary certificate are currently included in the package of plant material that is shipped to a foreign country.

3.4 Phytosanitary Certificate Issuance and Tracking System (PCIT)

Individuals or organizations that regularly obtain phytosanitary certificates will benefit from establishing an account in the online Phytosanitary Certificate Issuance and Tracking System (PCIT) of APHIS. The PCIT enables submitting the PPQ Form 577 and paying the inspection fee. It is also used by inspectors to create the phytosanitary certificate, all in a secured format to ensure data integrity and enable electronic archiving and reporting features. Additionally, PCIT account users have access to the Phytosanitary Export Database (PExD). APHIS populates this database with information summarizing foreign countries’ phytosanitary requirements. It is a useful resource for planning a foreign shipment from the U.S. to another country. However, the conditions specified by the foreign import permit or correspondence with their NPPO take precedence over PExD in determining the requirements for the plant material to enter a foreign country.

4. movement of threatened and endangered plant material

The international movement, either import or export, of threatened and endangered plant material is a special and complex operation, with separate processes from those described in the preceding sections. The U.S. regulations are based on the Endangered Species Act (ESA) which became law in 1973, and the Convention on International Trade in Endangered Species of Wild Fauna and Flora (CITES), which entered into force in 1975.

The ESA is designed to protect and recover critically imperiled species and their habitats in the U.S. Information on plants regulated under the ESA can be found on the USFWS Environmental Conservation Online System. Amendments to the ESA also help the U.S. to meet its obligations under CITES.

CITES is a multilateral international treaty designed to ensure the survival of about 36,000 species of threatened and endangered animals and plants. The list of about 30,000 plant species covered by CITES is recorded in three updates (Appendices I, II, II) issued by the Conference of Parties. Some are relevant to agricultural genetic resource collections and research, especially for medicinal and ethnobotanical plants. Because CITES covers animals and plants, both the U.S. Fish and Wildlife (FWS) Service of the Department of Interior and USDA-APHIS have regulatory authority over, and issue permits for, their international movement. Useful sources for further information about movement of plant material covered by CITES, confer a searchable database of the appendices maintained by the UN Environment Programme World Conservation Monitoring Centre, and content from the FWS and APHIS.

There are also restrictions on movement of threatened and endangered plants within the U.S. at both the federal and state levels. The searchable Plants Database, maintained by the USDA Natural Resources Conservation Service, is a comprehensive source for information about such plants. Permitting for movement of in situ threatened and endangered plants within the U.S. is delegated to the federal or state entity with jurisdiction over the area where the plants are precisely located.

5. Conclusion

The international and national movement of plant material, including germplasm, is essential for trade, commerce, and research. Such exchanges, however, risk introducing pests to the importing country or region. Regulations are enacted and enforced to minimize these risks, and it is essential for both those sending and receiving plant material to be aware of, and comply with, them. USDA-APHIS implements and enforces federal regulations, in partnership with state departments of agriculture, in the U.S. Both inspections and proper documentation are key for protecting against the unintentional movement and establishment of pests.

6. additional information

Banner images (from left to right): Wheat stem rust symptoms (Photo credit: USDA-Agricultural Research Service (USDA-ARS)); Plum pox virus symptoms (Photo credit: USDA-ARS); Asian longhorned beetle (Photo credit: USDA-APHIS); Potato cyst nematode (Photo credit: USDA-ARS).

7. Acknowledgments

Citation: Williams KA, Kinard G. 2020. Phytosanitary and Regulatory Issues in the Movement of Plant Genetic Resources: A U.S. Perspective. In: Volk GM (Ed.) Fundamentals of Plant Genebanking. Fort Collins, Colorado: Colorado State University. Available from:

Chapter editors: Gayle Volk, Katheryn Chen

The authors appreciate content reviews provided by Shailaja Rabindran and Matthew Travis (USDA-APHIS), and Jennifer Freidman (USDA-ARS).

This content pertains to a topic subject to frequent revisions and change. Current and authoritative information is most appropriately obtained from the National Plant Protection Organization of the country in which the reader resides, which is USDA-APHIS in the U.S. This project was funded by the USDA-ARS and grant 2020-70003-30930 from the USDA-National Institute of Food and Agriculture-Higher Education Challenge Grant Program. USDA is an equal opportunity provider and employer. Mention of trade names or commercial products in this article is solely for the purpose of providing specific information and does not imply recommendation or endorsement by the U.S. Department of Agriculture.


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