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International Plant Protection Convention
Develop guidelines for choosing a substitute pest for next meeting
2010_TPPT_Jul_79
Agenda: 13.1
Using surrogate species in the development of
phytosanitary treatments
Background
Extract from: Report of the meeting of the Technical Panel on Phytosanitary
Treatments (excerpts), 26-30 January 2009, Tokyo, Japan
6.4 TPFQ (December 2008)
A member enquired whether there were any criteria for determining appropriate
surrogates. The TPPT noted that the draft criteria for future ISPM No. 15 treatments
use the terms ‘equal biological characteristics and response to the treatment’, but the
Secretariat indicated that additional work could be done to define criteria for
choosing surrogates. It was agreed that the TPPT should develop draft guidelines for
choosing a surrogate pest and put this on the work programme. Some members
expressed the view that the new system may be very strict in regard to the provision of
data and these may limit the number of applications for the approval of treatments.
Extract from the Report of the Standards Committee (November 2008)
101.

The SC agreed the following criteria should be used when considering treatment
suitability for inclusion in ISPM No. 15:
that all treatments submitted in response to the 2006 and 2007 call for treatments for
inclusion in ISPM No. 15 should be evaluated for equivalence to the current ISPM
No. 15 methyl bromide treatment in the following manner. It must be demonstrated in
compliance with ISPM No. 28 and to be at least 99.99683% effective against
Anoplophora glabripennis (Asian longhorn beetle) and Bursaphelenchus xylophilus
(Pinewood nematode) or appropriate surrogates.

Box 1
Target species: The species that is of quarantine concern to an importing country.
Surrogate species: The species that is tested instead of the target species.
Target treatment: The quarantine treatment being demonstrated by the exporting
country to protect the importing country from a quarantine pest (i.e. the target species)
that is present in the importing country.
It is assumed (usual approach), or can be demonstrated (preferable), that the surrogate
species responds to the target treatment in the same way (or preferably is less tolerant)
as the target species.
It is acknowledged that surrogate species are not the same as the target species and
that they may not react to a treatment in the same way as the target species may. It is
also acknowledged that many target species are very difficult to use in scientificallybased studies due to a number of good reasons and that it is desirable that more
tractable surrogate species can be used instead. We need to produce selection criteria
that takes account of the positives while acceding to the possibility of negatives. Such
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International Plant Protection Convention
Develop guidelines for choosing a substitute pest for next meeting
2010_TPPT_Jul_79
Agenda: 13.1
negatives may be used in bilateral negotiations and in reviewing proposed treatment
schedules for future regional and international approval.
Some definitions
1. Simply put, a surrogate species is one that can be studied so that data from it
will also apply to another species (which I will label “target species”). One can
use a set of species or just one species (“umbrella” species) to represent all
target species. One species can be used to represent another single target
species. The surrogate species concept is used in environmental as well as
dose-response studies.
2. Surrogate Species: A species that is tested to estimate responses of other
species, for which direct testing is impractical (ASTM, 2002).
3. When target species are not available to a research group, more readily
available surrogate species may be used if these have been shown to be more
tolerant of the treatment (Ormsby, 2009). This is applicable to the “most
treatment-tolerant species” concept where treatments are applied to a set of
similar target species and the most treatment-tolerant of those species is then
used as a “surrogate” representing all target species in that group.
4. Definition of Focal species (or Surrogate species) - small number of species
whose distributions and abundances are well known; used in conservation
planning; assumed to reflect the distribution and abundance of the regional
biota; subsumes indicators and umbrella species (Hannon and McCallum,
2003)
Examples in practise
USDA Fruit Fly Cooperative Control Program, 2001: “Risk was characterized by
comparing the estimated dose and the benchmark toxicity value. The benchmark
values were the LD1 and the LC1 (the calculated dose lethal to 1% of the population,
usually for a surrogate species).”
“The test organism selected as a surrogate for each species was the most
taxonomically similar species or one of similar size and trophic level. Generally, the
lowest literature toxicity value for this species was selected.”
“Toxicity data are available for very few species, requiring the selection of surrogate
species for analysis. This is particularly true for SureDye and spinosad which have
only recently been developed for use as pesticides. Often there were no data for
similar species, and selection was based primarily on sensitivity. The choice of a
surrogate had a great effect on the assessment of risk. Information about surrogate
species is given in the Nontarget Species Risk Assessment (USDA, APHIS, 1998b).”
(Author’s note: I was unable to obtain a copy of this document.)
“Surrogate Species: A substitute species that can be compared with a lesser known or
more rare species.”
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International Plant Protection Convention
Develop guidelines for choosing a substitute pest for next meeting
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Agenda: 13.1
Baker and Stuckey, 2008: “Current prioritisation assessment protocols for invasive
species tend to be based on species’ attributes and there is often variation in scope,
type and quality of information available. For example, predictions on a cryptic
species, environmental or economic impact are often reliant on expert opinion rather
than on specific data. Expert opinion is of substantial use, but the effect of linguistic
(context and definitions) and epistemic (knowledge about) uncertainty needs to be
accounted for when determining risk. The difficulty of measuring environmental and
social impact in financial terms has been noted by many authors using risk assessment.
Lack of life history data for many species can also be problematic, with closely
related species often being used as surrogates.”
Garcia et al., 2002: “We conducted a study to test the effect of anticoagulant
rodenticides on captive geckos. We used the Mona Island Gecko, Sphaerodactylus
monensis as a surrogate species because it is very abundant, lives in a comparable
habitat, and is similar in size and in feeding habits to the Monito Island gecko.”
Nishimoto, 1978: “For the purpose of bio-assay, Lyctus beetle should be used, but the
author has not been successful in rearing Lyctus continuously in his laboratory.
Therefore, the adult of Tribolium castaneum HERBST was used as its substitute
insect. Ten-day old adults were used. Those were previously reared in the laboratory
with wheat flour as food.”
Booth and Wickstrom, 1999: “Huberia brouni is difficult to maintain in captivity (the
colony died out when maintained in laboratory conditions), and due to its small size,
would require very large numbers of individuals in each group to obtain enough tissue
for 1080 residue analysis. Therefore, a related species of the same genus, H. striata,
was used as a surrogate. H. striata appears to have similar feeding habits to H. brouni,
but is approximately 4 times larger, is easy to maintain in captivity, and is
common…”
Fleming et al., 2005: “A native species, the cottonwood borer (CWB), Plectrodera
scalator (Coleoptera: Cerambycidae), was used as a surrogate cerambycid species for
our studies because ALB is under quarantine in the United States. The cottonwood
borer (CWB) is closely related to ALB and similar in size.”
Poland et al., 2002: “In the laboratory, we reared cottonwood borer larvae (CWB), a
surrogate for ALB, on artificial diet treated with various concentrations of
imidacloprid and azadirachtin.”
Romeis et al., 2008: “Despite recognized limitations, the application of the surrogate
concept is widely applied in related fields including regulatory toxicity testing and
environmental monitoring.”
“….more standardized, validated test protocols for surrogate test species may need to
be developed. These are needed to ensure data comparability and facilitate
international regulatory acceptance.”
Wenger, 2008: “(1) identify one or more candidate surrogate species, (2) model the
relationship between the stressor and the response variable of interest for the surrogate
species, (3) adapt the stressor–response relationship from the surrogate species to a
model for the target species, possibly using Bayesian methods, and (4) incorporate
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International Plant Protection Convention
Develop guidelines for choosing a substitute pest for next meeting
2010_TPPT_Jul_79
Agenda: 13.1
additional data as they become available and adjust the response model of the target
species appropriately.”
World Wildlife Fund Canada. (2005): “Submitted materials may be taken from
published or unpublished literature. If this kind of information is not available for the
exact organism in question, published or unpublished material from a surrogate species
may be acceptable, or data from original tests with the MPCA.”
USDA, 2010: “Web-ICE version 3.1 - release January 2010. Web-ICE estimates
acute toxicity (LC50/LD50) of a chemical to a species, genus, or family from the
known toxicity of the chemical to a surrogate species. Web-ICE has modules to
predict acute toxicity to aquatic (fish and invertebrates) and wildlife (birds and
mammals) taxa for use in ecological risk assessments, and also contains modules that
generate Species Sensitivity Distributions (SSDs) from Web-ICE generated data.”
(Also see Raimondo et al., 2010.)
Ecological Risk Assessment Focus Group, 2000: “Surrogate Species: Limited data is
available on sensitive species that represent wildlife at the national and state levels.
For this reason, EPA recommends use of surrogate species in laboratory toxicity
testing. Data obtained in these tests are extrapolated to evaluate potential effects to
organisms present on the site. At the end, the hazard quotient (HQ) is calculated using
a hypothetical dose which organisms at the site are exposed to, divided by a
toxicological value (LC50, NOEC). If the HQ is higher than 1, it is assumed that
adverse effects are possible. A number of ecological levels of concern (LOCs) have
been established by EPA for different endpoints to facilitate the decision making
process. The problem is, all of the numbers used to get to this point are not measured
values. The majority of the numbers are based upon data derived for other species,
under different conditions.”
USDA, 2002. “The CWB appears to be a useful surrogate model for ALB due to its
high genetic relatedness, similar behavior, host range, size, and response to artificial
diet, and other laboratory conditions”.
http://www.aphis.usda.gov/plant_health/plant_pest_info/asian_lhb/downloads/researc
h.pdf (Note: CWB - Cottonwood borer; ALB – Asian Longhorned Beetle)
Comments
Whether surrogates have been used to represent target species for environmental,
phytosanitary or invasion-potential studies there are positive and negative aspects.
The positive aspects include ease of study and the negatives include the difficulty in
demonstrating that the two species react in the same way to a treatment. Published
literature indicates a preference that the surrogate species should be less tolerant to the
treatment than the target species to ensure quarantine (if not scientific) robustness.
The overriding desire for an appropriate surrogate is that the surrogate should be
exactly the same as the target species in its habits, size, damage level and damage
potential but needs to be easy and cheap to work on whether they are laboratory
reared (more common) or wild-gathered (rarely used but possible).
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International Plant Protection Convention
Develop guidelines for choosing a substitute pest for next meeting
2010_TPPT_Jul_79
Agenda: 13.1
The US Environmental Protection Agency (EPA) has collated data on toxicity of a
range of chemicals to a range of species (at present mainly aquatic and avian) and has
developed a model for species comparisons to toxins. This is the Web-based
Interspecies Correlation Estimation (Web-ICE) for Acute Toxicity (see Raimondo et
al., 2010, below). As this is developed for other species, including invertebrates, it
may be used extensively in the future. But then this modelling system is being
targeted as lacking complete and unambiguous scientifically based data. However, it
is predicted that the model will improve as more data is added.
As shown above, Wenger, 2008, suggests the following course of action when
choosing surrogate species:
(1) identify one or more candidate surrogate species,
(2) model the relationship between the stressor and the response variable of interest
for the surrogate species,
(3) adapt the stressor–response relationship from the surrogate species to a model for
the target species, possibly using Bayesian methods, and
(4) incorporate additional data as they become available and adjust the response
model of the target species appropriately.
The Web-ICE model appears to parallel Wenger, 2008, in developing, and continuing
to develop, such models.
Score Test for Surrogate Species Suitability
For more immediate use within IPPC needs I propose something along the lines of a
Score Test for Surrogate Species Suitability as described in the two tables below.
You will see that Table 2 shows a scoring system for surrogate applicability. I have
made suggestions on what to score, and what values to give attributes but I have not
indicated how to treat the resultant final scores for decision-making.
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International Plant Protection Convention
Develop guidelines for choosing a substitute pest for next meeting
2010_TPPT_Jul_79
Agenda: 13.1
Table 1. The need for a surrogate species in developing phytosanitary treatments
Target species
Rare
Not endemic or established in region of
research, quarantine issue
No / insufficient quarantine infrastructure /
facility in which to research target species
Difficult to culture
No rearing techniques developed
Expensive to rear
Dangerous to handle
Difficult to find / grow sufficient numbers
Lack of knowledge of habits, phenology,
etc
Surrogate species
Common
Endemic, established in research
region
Can more easily be laboratory reared
Can rear sufficient quantities for
statistical correctness
Not expensive to rear
Safe to handle
Similar dietary requirements with
respect to quarantine problem (e.g.
both target and surrogate attack the
same product and the same part of the
product)
Similar life history in target product
OTHERS?
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International Plant Protection Convention
Develop guidelines for choosing a substitute pest for next meeting
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Agenda: 13.1
Table 2. Checklist for suitability as a surrogate species: Evidence of similarity
Attribute
Similarity Reason for given score B
score A
Reason
score C
Order
Family
Genus
Species (different
strain, sub-species,
variant, etc)
[“taxonomic distance”]
Host (i.e. target
product)
Host range
Life history
Feeding regime
Reaction to treatment
Tolerance to treatment
(preferably less tolerant
at same temperature,
duration of exposure,
dose concentration, etc)
[“toxicologically
representative”]
Habitat type (e.g.
tropical, temperature)
Level of damage to
target product
Part/s of target product
damaged
Phenology
Size
OTHERS?
A
4 (same), 3 (highly similar), 2 (similar), 1 (slightly similar), 0 (different)
There should be a reason for the score that is given: it may be scientific (based on
comparative research between the target and the surrogate species, published papers,
reports, etc), historical (the surrogate has been used for the target species for many
years without problems), based on consensus of knowledgeable opinion and expertise
(meeting reports showing agreement), etc.
C
A score for the quality of the Reason should also be given: 2 (internationally
acceptable, peer-reviewed publication OR expert consensus), 1 (unpublished data,
observations OR proceedings (not peer-reviewed) OR historical basis, 0 (anecdotal
evidence only OR no reason given, able to be given OR no scientific or anecdotal
evidence exists)
B
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International Plant Protection Convention
Develop guidelines for choosing a substitute pest for next meeting
2010_TPPT_Jul_79
Agenda: 13.1
References and further reading material
Antwi, Frank B. and Robert K.D. Peterson. (2009). Toxicity of δ-phenothrin and
resmethrin to non-target insects. Pest Management Science, 65: 300–305
ASTM. (2002.) Standard Terminology Relating to Biological Effects and
Environmental Fate. Standard E 943-00 in: Annual Book of Standards. Vol. 11.05
Biological Effects and Environmental Fate; Biotechnology; Pesticides. ASTM
International, West Conshohocken, PA (reference only)
Baker, Jeanine and Michelle Stuckey. (2008). Prioritising the impact of exotic pest
threats using Bayes net and MCDA methods. ACERA Project No. 07/07. Final Report,
February 2008. Australian Centre of Excellence for Risk Analysis (ACERA).
Booth, L.H. and M.L. Wickstrom. (1999). The Toxicity of Sodium
Monofluoroacetate (1080) to Huberia Striata, a New Zealand Native Ant. New
Zealand Journal of Ecology 23(2): 161-165.
Caro, T.M. and Gillian O’Doherty. (1999). On the use of surrogate species in
conservation biology. Conservation Biology 13(4): 805-814.
Ecological Risk Assessment Focus Group. (2000). Ecological Risk Assessment,
Florida Position Paper, Preliminary Draft, 6 May 2000. Report to the Florida
Department of Environmental Protection Contaminated Soils Forum.
Favreau, Jorie M., C. Ashton Drew, George R. Hess, Matthew J. Rubino, Frank
H. Koch and Katherine A. Eschelbach. (2006). Recommendations for assessing the
effectiveness of surrogate species approaches. Biodiversity and Conservation 15(12):
3949-3969.
Fleishman, Erica, Dennis D. Murphy, and Robert B. Blair. (2001). Selecting
Effective Umbrella Species. Conservation Magazine 2(2):17-23.
Fleming, Mary R., John J. Janowiak, John M. Halbrendt, Leah S. Bauer,
Deborah L. Miller, and Kelli Hoover. Feasibility of eradicating Cerambycid larvae
and pinewood nematodes infesting lumber with commercial 2.45 GHz microwave
equipment. Penn State College of Agricultural Sciences, School of Forest Resources.
35 pages. http://woodpro.cas.psu.edu/Nematodes1.pdf (accessed 21 June 2010)
Fleming, Mary R., Mahesh C. Bhardwaj, John J. Janowiak, Jeffrey E. Shield,
Rustum Roy, Dinesh K. Agrawal, Leah S. Bauer, Deborah L. Miller and Kelli
Hoover. (2005). Noncontact ultrasound detection of exotic insects in wood packing
materials. Forest Products Journal 55(6): 33-37.
García, M.A., C.E. Diez, and A.O. Alvarez. (2002). The eradication of Rattus rattus
from Monito Island, West Indies. In: Proceedings of the International Conference on
Eradication of Island Invasives. Eds: C. R. Veitch and M. N. Clout. Occasional Paper
of the IUCN Species Survival Commission No. 27. Pages 116-119.
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International Plant Protection Convention
Develop guidelines for choosing a substitute pest for next meeting
2010_TPPT_Jul_79
Agenda: 13.1
Hannon, Susan J. and Cindy McCallum. (2003). Using the focal species approach
for conserving biodiversity in landscapes managed for forestry. Sustainable Forest
Management Network Synthesis Paper. Dept of Biological Sciences, University of
Alberta. 59 pages.
Lagunas-Solar, M.C and C. Pina. (2005). Update on Metabolic Stress Disinfestation
and Disinfection. Annual International Conference on Methyl Bromides Alternatives
and Emissions, San Diego, CAL, October31 – November 4, 2005.
Niemi, Gerald J. and Michael E. McDonald. (2004). Application of Ecological
Indicators. Annual Review of Ecological Evolution Systems. 35:89–111.
Nishimoto, Koichi. (1978). Study of Insect Proof Plywood by Mixing Chlordane
with the Glue. Wood Research No. 64: 9-23.
Ormsby, Michael. (2009). Developing phytosanitary treatments for international
trade. In: IUFRO International Forest Biosecurity Conference Incorporating the 6th
International Forest Vegetation Management Conference. 16-20 March 2009, Rotorua,
New Zealand Eds: Margaret Richardson, Carolyn Hodgson, Adrienne Forbes. New
Zealand Forest Research Institute Limited.
Poland, Therese M., Robert A. Haack, Leah S. Bauer, Toby R.Petrice, Deborah
L. Miller, and Houping Liu. (2002). Overview of Asian Longhorned Beetle
Research by the USDA Forest Service, North Central Research Station, in East
Lansing, Michigan. Proceedings, U.S. Department of Agriculture Interagency
Research Forum on Gypsy Moth and Other Invasive Species. January 15-18, 2002.
Raimondo, S., D.N. Vivian, and M.G. Barron. (2010). Web-based Interspecies
Correlation Estimation (Web-ICE) for Acute Toxicity: User Manual. Version 1.1.
EPA/600/R-10/004. Gulf Breeze, FL.
Romeis, Jörg, Detlef Bartsch, Franz Bigler, Marco P. Candolfi, Marco M.C.
Gielkens, Susan E. Hartley, Richard L. Hellmich, Joseph E. Huesing, Paul C.
Jepson, Raymond Layton, Hector Quemada, Alan Raybould, Robyn I. Rose,
Joachim Schiemann, Mark K. Sears, Anthony M. Shelton, Jeremy Sweet,
Zigfridas Vaituzis and Jeffrey D. Wolt. (2008). Assessment of risk of insectresistant transgenic crops to nontarget arthropods. Nature Biotechnology 26(2):203208.
USDA Fruit Fly Cooperative Control Program. (2001). Final Environmental
Impact Statement,
USDA. (2002). Asian Longhorned Beetle. Proposed FY 2002 Research &
Technology. (Objective 2) Evaluate entomopathogens for utility for biocontrol and
(Objective 3): Evaluate Asian longhorned beetle, Anoplophora glabripennis
(Motschulsky), entomopathogens using a native cerambycid, the cottonwood borer,
Plectrodera scalator (Fabricius), as a surrogate host.
http://www.aphis.usda.gov/plant_health/plant_pest_info/asian_lhb/downloads/researc
h.pdf. (Accessed 21 June 2010)
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International Plant Protection Convention
Develop guidelines for choosing a substitute pest for next meeting
2010_TPPT_Jul_79
Agenda: 13.1
Wang, Baode, Victor C. Mastro, and Win H. McLane. (2000). Impacts of
Chipping on Surrogates for the Longhorned Beetle Anoplophora glabripennis
(Coleoptera: Cerambycidae) in Logs. Journal of Economic Entomology. 93(6): 18321836.
Wenger, Seth J. (2008). Use of Surrogates to Predict the Stressor Response of
Imperiled Species. Conservation Biology, 22(6):1564–1571.
Wiens, John A., Gregory D. Hayward, Richard S. Holthausen, and Michael J.
Wisdom. (2008). Using Surrogate Species and Groups for Conservation Planning and
Management. BioScience 58(3):241-252
World Wildlife Fund Canada. (2005). Critical regulatory path for biocontrol agents.
Prepared by Vijay Cuddeford for Agriculture and Agri-Food Canada, in preparation
for the workshop Microbial Biocontrol Agents: Registration, Commercialization &
Adoption Issues, Saskatoon, February 28 to March 1, 2005.
Wren, Sarah, D. Brent Gurd, Andrea Pomeroy, Kristen Gorman. (2006). Birds,
Bird Habitat and the Mackenzie Gas Project: Important Bird Areas and Migratory
Birds as Valued Components, Nature Canada Intervener Report For October 19 – 20,
2006 Topic-specific General Hearing (Topic #7 Wildlife and Wildlife Habitat,
including Birds and Bird Habitat). 25 pages.
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