Lesson 2: Terminology and Uncertainty in Pest Risk Analysis

Topic 1: Important Terms and Concepts in PRA

In this topic, you will learn about the terms and definitions that are important for PRA. The IPPC has a reference standard, ISPM No. 5—Glossary of Phytosanitary Terms—which lists the terms and definitions with specific meaning to plant protection activities worldwide. ISPM No. 5 was developed to provide a harmonized, internationally agreed upon vocabulary associated with the implementation of the IPPC and its international standards.

Objectives:

Explain the importance of internationally agreed upon plant health definitions in promoting harmonization and improving communication when addressing plant protection issues
Understand how phytosanitary terminology is added, revised, and updated
Review and explain the term pest risk analysis
Explain the concept of quarantine pest, including its essential components
Explain the concept of measures and define related terms

Phytosanitary Terminology and PRA

One of the most important reference standards adopted by the IPPC is ISPM No. 5—Glossary of Phytosanitary Terms (IPPC, 2013). This reference standard is a compilation of terms (and definitions) that are commonly used in plant protection. ISPM No. 5 promotes harmonization and improves communication and understanding of phytosanitary issues among the contracting parties to the IPPC. ISPM No. 5 is updated annually to add, remove, revise, or further clarify terms and definitions important to all plant protection activities, including pest risk analysis. Below, we will examine some of the most important terms and definitions for pest risk analysis and study their specific meaning. The importance of harmonized terminology lies not only in defining the terms, but in describing the concepts and nuances contained in the terms.

Pest Risk Analysis

ISPM No. 5 defines pest risk analysis as

“the process of evaluating biological or other scientific and economic evidence to determine whether an organism is a pest, whether it should be regulated, and the strength of any phytosanitary measures to be taken against it.”

Let’s examine each part of the definition more closely.

“The process of evaluating biological or other scientific and economic evidence” reminds us that pest risk analysis should be based on different types of evidence.
Pest risk analysis is done “to determine whether an organism is a pest.” This means that relevant biological evidence should be used to decide if the organism in question is harmful to plants.
If the pest is deemed harmful, a determination must be made as to “whether it should be regulated.” This determination is made by assessing whether the organism meets the definition of a quarantine pest or a regulated non-quarantine pest. See Quarantine Pest, below.
You will see below that the definition of quarantine pest requires that the organism has the potential to cause economic harm. The need to examine economic evidence is therefore clear.
Finally, pest risk analysis must determine “the strength of any phytosanitary measures to be taken” against the pest. This part of the definition indicates that there should be a clear relationship between the level of risk (a pest might represent) and the level (or strength) of risk management (measures) applied for that pest.

Quarantine Pest

ISPM No. 5 defines quarantine pest as

“a pest of potential economic importance to the area endangered thereby and not yet present there, or present but not widely distributed and being officially controlled.”

This term is central to pest risk analysis.

The definition contains a number of important concepts and principles related to the IPPC and to the SPS Agreement. Let’s consider its components separately and examine the regulatory implications behind each one.

“A pest of potential economic importance” This statement clearly indicates that there must be some potential for economic harm associated with the pest. ISPMs Nos. 5 and 11 provide guidance on what factors to consider when determining a pest’s potential economic importance. This supplemental guidance tells us that social as well as environmental effects can be considered economic effects.
“to the area endangered thereby” This statement suggests that a specific area should be defined when considering the pest’s potential for causing economic harm. A pest might or might not be able to establish in the entire PRA area (area in relation to which a pest risk analysis is conducted). It is therefore useful to distinguish between the endangered area, which is the area where a pest can establish, and the PRA area, which is the area considered in the pest risk analysis. Sometimes these areas are the same, but for large countries with many different climatic zones, the endangered area may be a small part of the PRA area.

“and not yet present there, or present but not widely distributed and being officially controlled” The first statement tells us that in order for a pest to be a “quarantine pest” of a country, it must not occur in that country. Recall that the principles of technical justification and national treatment in the SPS Agreement and the IPPC say that measures against a pest are not technically justified if the pest already occurs in a country and is not being officially controlled. The next part of the statement indicates that an exception can be made if the pest has a limited distribution and is under an official control (containment or eradication programs officially conducted by the NPPO).

The definition of “quarantine pest” does not make a distinction over taxon; the term applies to all relevant taxa including arthropods, other invertebrates (such as mollusks and nematodes), pathogens, and weeds.

Pathway

ISPM No. 5 defines pathway as “any means that allows entry or spread of a pest.” When conducting PRA, it is important to define the pathway(s) by which the pest can enter and/or spread. PRAs may be conducted on groups of pests that follow a single well-defined pathway (e.g., plants and plant products) or may focus on a single pest that is capable of following one or more pathways.

Other “Pest” Terms

In addition to the definition for quarantine pest described above, ISPM No. 5 has a number of additional terms used to define and describe pests. It is important to be able to distinguish between these terms and understand the relationships between them. Hold your computer mouse over the terms in the diagram below to learn more.

Interrelationship Between “Pest” Terms

Phytosanitary Measures

When discussing pest risk management (which is the subject of a later module in this series), it is important to understand a set of terms related to phytosanitary measures that might be used to reduce, eliminate, or manage risk. Let’s briefly look at the definitions of these terms in ISPM No. 5. The terms will be discussed again, in detail, in the Risk Management Module.

Phytosanitary measure

Any legislation, regulation, or official procedure having the purpose to prevent the introduction and/or spread of quarantine pests or to limit the economic impact of regulated non-quarantine pests.

Phytosanitary measure is a very broad or “umbrella” term that encompasses several narrower definitions related to managing pest risk. These narrower terms are defined below.

Terms to Know and Understand: Measures

Other terms related to the application of phytosanitary measures in particular situations (such as emergency measures, provisional measures, and redundant measures) will be explained in the Risk Management Module.

Other terms related to PRA

These definitions come from ISPM No. 5.

Pest risk (for quarantine pests)

The probability of introduction and spread of a pest and the magnitude of the associated potential economic consequences.

Pest risk assessment (for quarantine pests)

The evaluation of the probability of the introduction and spread of a pest and the magnitude of the associated potential economic consequences.

Pest risk management (for quarantine pests)

Evaluation and selection of options to reduce the risk of introduction and spread of a pest.

The definition given below does not come from the phytosanitary community. Nevertheless, it highlights the importance of the components of risk analysis (risk assessment, risk management, and risk communication) mentioned earlier in this module.

Risk analysis

The practice of evaluating (or assessing) risk, managing risk, and communicating about risk.

In its broadest sense, risk communication is the process of explaining risk. Risk communication is not defined in ISPM No. 5, but is mentioned in ISPM No. 2 (Framework for Pest Risk Analysis). ISPM No. 2 states that risk communication is an interactive process allowing exchange of information between the NPPO and stakeholders. Risk communication will be the subject of a later module.

PRA Terminology Example

Now that you’ve had a chance to become familiar with some basic phytosanitary terminology, check your understanding of these definitions in the following example.

Bugus terribilis is found in Exportland, but appears to not be present in Importland. Importland is interested in importing an agricultural commodity from Exportland, but is unsure if Bugus terribilis poses a risk to their country.

What might Importland need to do to determine if Bugus terribilis poses a risk to their country?

A PRA should be conducted for Bugus terribilis.

From Importland’s perspective what kind of pest might Bugus terribilis be?

Bugus terribilis might be a quarantine pest for Importland.

A quarantine pest is defined in ISPM No. 5 as “a pest of potential economic importance to the area endangered thereby and not yet present there, or present but not widely distributed and being officially controlled.”

In order to qualify as a quarantine pest for Importland, in this example Bugus terribilis would need to satisfy the following conditions:

Bugus terribilis has potential economic importance to (the plant resources present in) Country B. A pest risk assessment can be used to determine this (see definition for pest risk assessment above).
Country B would need to confirm that Bugus terribilis is not present in its own country (Country B), perhaps with surveillance (which is a phytosanitary action—see definition above).
If Bugus terribilis is determined to be present in Country B, then the extent of its distribution must be known (again, perhaps with surveillance which is a phytosanitary action—see definition above), and the status of any official programs by the NPPO (official control) must be verified.
If Bugus terribilis is determined not to be present in Country B and the pest risk assessment determines that the risk for economic harm is high, then Country B and Country A must come to an agreement concerning which phytosanitary measures (see definition above) are acceptable to both countries in order to manage the risk posed by Bugus terribilis.

In this topic, we carefully examined some important plant health terms directly related to pest risk analysis and its components (risk assessment, risk management, and risk communication). You were reminded that the Glossary of Phytosanitary Terms (ISPM No. 5) promotes harmonization and improves communication and understanding of phytosanitary issues among the contracting parties to the IPPC.

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