National Plant Board

Plant Quarantine, Nursery Inspection, and Certification Guidelines

Appendix D

Guidelines for Pest Surveillance, Pest Survey, and Pest Ratings Lists*


Pest prevention is a planned, organized and ongoing governmental program for the purpose of halting the introduction, colonization, and establishment of pests that would cause significant agricultural, environmental, and/or societal harm in an area where the pest does not already occur. There are many factors that limit the ability of government to accomplish this goal efficiently. The purpose of this Appendix is to set forth guidelines for pest surveillance, pest survey, and the development of pest rating lists. The product of these functions would be a pest distribution database that is a basic essential for pest prevention.

Pest prevention agencies must be able to 1) see the possibility for harm, 2) determine the probability for harm, and 3) take appropriate avoidance measures. Pest surveillance plays a critical role in the ability to see the possibility for harm; and pest prevention agencies are largely dependent on other pest prevention agencies to maintain pest distribution databases and make them readily accessible. Many countries simply do not have the resources to do this, leaving importing countries with the need to inspect pest host commodities arriving at ports of entry and using the pest interception data generated there as a means of identifying the possibility for harm.

To determine the probability for harm, pest risk analysis (PRA) is required. A pest prevention agency must know what pests are already present in the area it represents; the biologies and host ranges of quarantine pests of concern; when, where, why and how harm could occur and to what degree; how the pest could be introduced; and the likelihood of colonization and establishment. In order to know what pests are already present in the area it represents, a pest prevention agency must conduct its own surveillance and survey activities.

Once the risk is identified, a pest prevention agency must decide if the cost(s) associated with preventing the probable level of harm are worth the benefits. If so, then it must take appropriate avoidance measures. It must select the appropriate pest risk mitigation measures or strategies, codify (enact as law) those requirements, enforce them, and reevaluate and revise as appropriate.

*Adapted from “Draft FAO Guidelines for Survey and Monitoring Systems”, August 11, 1994.


1. “Area” means any political division or subdivision or any officially defined area including adjacent parts of contiguous political divisions or subdivisions. [Political divisions include nations and states or provinces within them. Political subdivisions include counties, parishes or municipios (in Mexico), and cities or municipalities. Officially defined areas also may include any other clearly defined and identifiable area including a specific property or facility.]

2. “Biotic agent” means any living entity.

3. “Delimitation survey” means a systematic search to determine the extent of an area infested by, or free from, a target pest.

4. “Detection survey” means a systematic search to determine the presence or absence of a target pest.

5. “Endemic pest” means native (indigenous) pests or pests permanently established in an area.

6. “Eradication” means elimination of a pest from a designated area. Eradication is determined by a negative, mutually agreed upon, verification survey for the target pest. (Pest Control is sometimes more broadly or generically defined to include all actions taken to reduce or eliminate pest populations including control, suppression, and eradication. See Appendix H, page 69, as an example.)

7. “Exotic pest” means a non-native (non-indigenous) pest or a pest not known to occur in an area.

8. “Mutually agreed upon” means agreement between or among trading partners as to pest eradication criteria or requirements, phytosanitary measures, or survey methods.

9. “New occurrence” means a pest occurrence not previously officially reported or a subsequent occurrence of a pest previously eradicated.

10. “Occurrence” means current presence of an endemic or exotic pest in an area.

11. “Official” means authorized, implemented and directed, or performed by a governmental plant protection organization.

12. “Pathway” means any natural or artificial means or avenue that allows for the movement of a pest from one area to another.

13. “Pest” means any biotic agent that causes harm or any abiotic disorder that is harmful. (See expanded definition in Appendix C.)

14. “Pest control” means the reduction of pest populations to the point that economic damage, injury or loss is reduced to an economically tolerable level. (Pest Control is sometimes more broadly or generically defined to include all actions taken to reduce or eliminate pest populations including control, suppression, and eradication. See Appendix H, page 69, as an example.)

15. “Pest free area” means an area kept free from a specific pest.

16. “Pest risk analysis” means characterizing the nature of pest hazard or harm; identifying the degree of probability or likelihood of harm; analyzing the degree to which risk mitigation measures or strategies can reduce the probability of harm to an acceptable level; and recommending pest risk mitigation measures or strategies.

17. “Pest Risk Management” means selection of pest risk mitigation measures; codification (enactment as law) of selected pest risk measures or strategies; enforcement of legal requirements; reevaluation; and revision or modification of requirements.

18. “Surveillance” means combined and ongoing acts of monitoring, collecting, confirming, documenting, and reporting pest data generated via private and public activities for the purpose of establishing and maintaining a valid and reliable (accurate and current) pest distribution database for any particular area.

19. “Survey” means the systematic search for pests in accordance with mutually agreed upon methods designed to assure confidence in their meaning and accuracy for pest prevention purposes such as control, suppression, eradication, verification of pest free areas, identification of possible harm, evaluation of the probability of harm, and taking appropriate actions to prevent predicted significant harm. Surveys may be performed for the purposes of detection, delimitation, or verification.

20. “Verification Survey” means a systematic, ongoing search to assure target pest freedom, determine the need for treatment, or determine the success of treatment. This kind of survey is sometimes called a monitoring survey.


A. Sources

Sources of plant pest distribution data include plant protection agencies, research institutions, university extension agents, consultants including pesticide advisers and dealers, scientific societies, nursery operators, growers, museums, and the general public. Information from these sources might be published or unpublished in the form of diagnostics and research reports; regulatory, scientific, and survey reports; trade articles; historical records; and contemporary observations.

B. Surveillance

Surveillance is a planned and well-managed system for periodic or ongoing access, verification, compilation and reporting of plant pest distribution data from as many sources as is economically feasible. The state plant protection agency should develop a central database and data retrieval system, verify all new data added, and provide for access by other agencies and interested or affected parties. Ideally, a read-only electronic system would be used.

C. Resources and Authority

Basic needs include adequate legal authority together with the staff, technical equipment and other resources necessary to operate the system.

To obtain the necessary pest distribution data might require legal mandates, cooperative agreements, memoranda of understanding, directives, or other vehicles that assure reporting.


Surveys may be categorized based on their purpose as “detection”, “delimitation”, or “verification”. As defined in this document, surveys are planned and often programmed systematic searches for pests. Survey plans should address the following:

Purpose Frequency

Area Quality Control

Pest(s) Diagnostics

Method(s) Documentation

Intensity Reporting

Discussions of the more important of these considerations follow:

A. Purpose

The purpose of the survey will be the most fundamental consideration in the design and conduct of a survey. Purpose relates to the size of the area to be surveyed, the pest(s) surveyed for, the methods used, and the intensity and frequency of the search. Is the survey needed simply to satisfy local concerns or is it needed to satisfy phytosanitary requirements such as pest free areas or growing season pest monitoring requirements? A survey to satisfy local concerns might not be very rigorous as to intensity and methodology whereas a survey to satisfy phytosanitary requirements would be jointly developed with trading partners to satisfy their levels of concern. The intensity and methodology is likely to be more rigorous.

B. Methods

The biology, life cycle and host range of a pest and its host(s) are fundamental survey factors that must always be taken into consideration. Other factors operate depending on the methods employed.

1. Trapping

Trapping considerations include:

level of confidence to be achieved

pest biology/life cycle

pest host range

pest colonization/establishment potential

availability of lures and traps

effectiveness and other factors associated with the lure

capture effectiveness of the trap(s)

trap density and placement

trap servicing and relocation intervals

trap durability


quality control

availability of resources

2. Sampling and Inspection

Sampling plans should always be biased toward discovery. Random or grid sampling plans can be overlaid with the appropriate bias to achieve the desired level of confidence.

Sampling considerations additionally include factors that influence:

the presence and distribution of the targeted pest(s)

detection of the pest [such as the selection of sampling sites, signs and symptoms, the accuracy or sensitivity of the technique(s) used, and the influence of cultural and pest management methods]


quality control

availability of resources

C. Quality Control

Every survey plan should make provision for quality control. This would include monitoring of those factors that significantly influence the effectiveness of the plan:

staff training in sampling methods, preservation and transportation of samples for identification and record-keeping associated with the sample.

proper use and maintenance of equipment and supplies.

D. Diagnostics

Timely and accurate diagnostics are essential. Professional diagnostic support for survey activities is characterized as follows:

professional staffing: expertise in the disciplines relative to pest and host identification

good laboratory practices

adequate facilities and equipment

access to specialists for verification where necessary

record-keeping, curation and storage facilities for voucher specimens

use of valid diagnostic methods

Quality management of diagnostics can be achieved by:

confirmation by other recognized experts

the submission of blind samples for diagnosis

unannounced inspections to check on laboratory practices.

One approach to management based on the foregoing and other appropriate criteria would be a laboratory accreditation program.

E. Record-Keeping and Reporting

Information maintained should be appropriate to the purpose(s) of the survey. Generally, it will include:

pest name (genus, species and possibly biotypes, strains, etc.)

host and plant part affected

means of collection (e.g. attractant trap, soil, sample, sweep net)

locality (e.g. location codes, addresses, co-ordinates)

additional information (e.g. nature of host relationship, Infestation status, other comments)

date of collection and name of collector

date of identification and name of identifier

Maintenance in an electronic database accessible by modem for read- only review by other agencies and interested and affected parties is encouraged.

Survey and other pest distribution data should be reported to cooperators, other agencies, and interested and affected parties as appropriate and requested.


Many states have good distribution and biological records of pests known to occur within their boundaries. They also have records of pest interceptions and a distribution-based system for rating pests. In some cases, the rating system and the resultant pest lists are codified (enacted or promulgated as state law). All states should establish such lists to assist the pest surveillance activities of other pest prevention agencies, as an aid to the performance of pest risk analyses and as a guide to regulatory action. The federal pest rating system is described in Appendix I on pages 71 and 72. Specific pest prevention actions are associated with each rating. The California Department of Food and Agriculture has a similar action-oriented pest rating system. As illustrated in the federal and the NAPPO rating systems, pest rating categories often are identified by letter designations, A being the category for the most serious (quarantine) pests and subsequent letters in the alphabet being used for pest categories of lesser regulatory significance. No letter rating system is specifically recommended but consistency with existing systems that do use the alphabetical approach is advised to avoid confusion. Generically, pest lists can be divided into categories as follows:

A. Endemic Pests [Native (indigenous) pests or pests permanently established in a state]

1. Common pests – Pests that exist in the state and which are generally distributed in those areas suitable for their survival.

2. Limited distribution – Pests that are known to occur in the state, but which are limited in distribution to a single small geographic area or a few small geographic areas which are widely separated within the state (widely but not generally distributed).

B. Exotic Pests [Non-native (non-indigenous) pests or pests not known to occur in a state]

1. Not known to occur – Pests that have not been found in the state; or which have been found and eradicated.

2. Intercepted pests – Pests that have been intercepted on quarantine shipments entering the state but eliminated by return out-of-state, destruction, or eradicative treatment applied to the infested commodity.

While the foregoing categories are adequate to deal with the matter of distribution, they do not address the issue of economic importance. However, such a categorization system serves well as a basis for establishing pest prevention guidelines for action. Economically important endemic pests might be regulated in settings where their presence is a factor in the quality of the commodity infested. For example, fruit and vegetable standards might be established to limit the incidence of a pest for human health reasons or pest freedom standards might be developed for nursery stock as a matter of pest control or consumer protection. From this viewpoint, the pests regulated could be considered “quality pests”. This concept is recognized in the North American Plant Protection Organization’s (NAPPO) rating system which refers to such pests as B-1 pests.

On the other hand, exotic pests are apt to be treated as quarantine pests. The level of risk, threat, or peril is a function of the introduction and establishment potential together with economic importance. In the NAPPO rating system, these would be A-1 quarantine pests if they do not occur and A-2 quarantine pests if they occur but are being officially controlled. One set of guidelines for determining the relative importance of quarantine pests is presented in Appendix E.

Pest prevention officials might elect to treat quarantine pests of moderate to low economic impact potential more like quality pests. The key to making this determination is the concept of “acceptable risk”. Measures selected to mitigate (reduce) pest risk might allow for tolerances (either specified or intrinsic to the mitigation measures selected) enforced by the pest prevention agency. The “acceptable level” is as defined in Appendix C.

As can be seen from the foregoing, pests endemic to one area (and not regulated or regulated as quality pests) could be considered exotics in an area where they do not occur (and might be regulated as quarantine pests and eradicated when discovered).