Risk Management Proposal:  
Amendment to the testing requirements for Pepino 
mosaic virus in the specific requirements for tomato 
(Solanum lycopersicum ) in import health standard 
Seeds for Sowing  (155.02.05)  
 
 
 
 
 
 
 
 
 
 
 
 
Prepared for  public consultation   
by Plant Germplasm Imports  
Animal and Plant Health Directorate  
 
 
 
 
 
 
 
 
October  2021 
 
 
Disclaimer  
 
While every effort has been made to ensure the information in this publication is accurate, the  Ministry  for 
Primary Industries does not accept any responsibility or liability for error of fact, omission, interpretation or 
opinion that may be present, nor for the consequences of any decisions based on this information.  
 
This publication is also available on the Ministry for Primary Industries  website at  
http://www.mpi.govt.nz/news -and-resources/publications/   
 
 
© Crown Copyright – Ministry  for Primar y Industries   
i Contents  Page 
 
Submissions  1 
1 General information  2 
1.1 Purpose  2 
1.2 Background  2 
1.3 Timing and consultation  2 
1.4 General context to consultation  2 
1.5 Background to proposed changes to the testing requirements for Pepino mosaic virus in the 
specific requirements for tomato ( Solanum lycopersicum)  3 
2 Proposed changes to the Standard  5 
2.1 Non-regulatory changes to the Standard  5 
3 Rationale for the proposed change to the Standard  6 
3.1 Proposed change to the testi ng requirements for Pepino mosaic virus  6 
3.2 Inclusion of guidance regarding the use of a bioassay in seed testing for the presence of pepino 
mosaic virus  7 
4 Feasibility of the proposed change to the Standard  8 
5 References  10 
6 Appendix 1  12  
Ministry for Primary Industries   Risk Management Proposal – Amendment to the testing requirements for Pepino mosaic viru s • 1 Submissions  
The Ministry for Primary Industries (MPI) invites comment from interested parties on proposed 
amendments to  the import health standard (IHS)  Seeds for Sowing  (the Standard).  
 
An import health standard  “specifies requirements to be met for the effective ma nagement of risks 
associated with arrival of craft or risk goods” (section 22, Biosecurity Act 1993).  
 
MPI would like feedback  on the following proposed changes to the Standard:  
• Amendment to the testing requirements for Pepino  mosaic virus  in the specific requirements 
for tomato  (Solanum lycopersicum ) 
 
Include the following in your submission:  
• The title of the consultation document in the subject line of your email  
• Your name and title  
• Your organisation’s name (if applicable)  
 
Send submissions to plantimports@mpi.govt.nz  by 22 November  2021 . 
 
Feel free to include any technical information you have that supports your submission. While we 
prefer email, if you would like to send your submission by post, you can mail it to : 
 
Plant Germplasm Imports  
Animal and Plant Health  Directorate  
Biosecurity Ne w Zealand  
Ministry for Primary Industries  
PO Box 2526  
Wellington 6140  
New Zealand  
 
Submissions received by the 22nd of November  2021  will be considered during the development of the 
amended standard . Submissions received after the closing date may be held on file for consideration 
when the standard  is next revised/reviewed.  
 
 
Official Information Act 1982  
Please note that your submission is public information , and it is MPI policy to publish submissions 
and the review of submissions on the MPI website. Submissions may also be the subject of requests 
for information under the Official Information Act 1982 (OIA). The OIA specifies that information is 
to be made a vailable to requesters unless there are sufficient grounds for withholding it, as set out in 
the OIA. Submitters may wish to indicate grounds for withholding specific information contained in 
their submission, such as information  being commercially sensiti ve or personal. Any decision to 
withhold information requested under the OIA is reviewable by the Ombudsman . 
  2 •  Risk Management Proposal – Amendment to the testing requirements for Pepino mosaic virus  Ministry for Primary Industries  1 General information  
 
1.1 PURPOSE  
(1) The purpose of this proposal  is to:  
• Provide relevant background information about the  import health standard Seeds for 
Sowing  (the Standard);  
• Outline the  propose d changes  to the  testing requirements for Pepino mosaic virus  
(PepMV)  in the specific requirements for  tomato  (Solanum lycopersicum ) in the 
Standard ;  
• Notify the intention to i nclude guidance information in the Standard regarding  the use of 
a bioassay for detection of  PepMV in seed samples . 
• Provide the rationale for the proposed changes  to the Standard and how they manage 
biosecurity risk; and to  
• Seek feedback on the proposed Standard.  
1.2 BACKGROUND  
(2) The Standard was issued on 20 September 2021  and came into effect on 20 September 2021 . 
The Standard was issued under section 22 of the Biosecurity Act (1993) and applies to seeds for 
sowing that are imported into New Zealand from forei gn countries and territories . 
1.3 TIMING AND CONSULTATION  
(3) The proposed amendments to the  Standard  was released for consultation on 22 October 2021  and 
will remain open for consultation until 22 November  2021 . 
1.4 GENERAL  CONTEXT TO CONSULTATION  
1.4.1 International regulation of risk goods  
(4) “The World Trade Organi zation Agreement on the Application of  Sanitary and Phytosanitary 
Measures (SPS Agreement)  sets in place rules that protect each country’s sovereign right to take 
the measures necessary to protect the life or health of its people, animals, and plants , while at 
the same time facilitating trade. It embodies and promotes the use of science -based risk 
assessments to manage the risks associated with the international movement of goods. The SPS 
Agreement guide s how New Zealand sets standards and makes decisions related to biosecurity. ” 
(MAF et al. , 2009 , p. 1 ) 
 
(5) “In particular, [it is] important to maintain  the standards of transparency and scientific rigour 
required by the SPS Agreement and to make decisions as quickly as possible. This will 
encourage other countries to comply with the rules of the SPS Agreement and also demonstrate 
that New Zealand’s stric t controls are justified to countries that challenge them. ” (MAF et al. , 
2009 , p. 13 ) 
1.4.2 Domestic regulation of biosecurity risks associated with craft arrivals  
(6) The N ew Zealand  biosecurity system is regulated through the Biosecurity Act 1993 (the Act). 
Section 22 of the Act describes a n import health standard and requires all risk goods imported 
into New Zealand  to be managed by one. MPI is the N ew Zealand  government ministry 
responsible for maintaining biosecurity standards for the effective management of risks 
associated with the importation of risk goods into N ew Zealand  (Part 3, Biosecurity Act 1993).  
Ministry for Primary Industries   Risk Management Proposal – Amendment to the testing requirements for Pepino mosaic viru s • 3 MPI is committed to the principles of transparency and evidence -based techn ical justification 
for all phytosanitary measures, new and amended, imposed on importing pathways. MPI 
periodically reviews all import health  standards, related documents and other standards so that 
the legal requirements are clear and information is consi stently presented and as easy as 
possible to understand.  
1.4.3 Biosecurity risk associated with seeds for sowing  
 
(7) Seeds for sowing can be a high -risk pathway for the introduction of regulated pests and diseases 
into New Zealand. Importation of seeds for sowing m ay be associated with risks arising from 
entry, establishment and spread of seed -transmitted and contaminating pests when infested 
seeds are introduced to an environment favourable to the pest. The transfer of seed -transmitted 
and contaminating pests to su itable hosts in the wider environment, can lead to them 
establishing and spreading to cause unwanted economic, environmental and social impacts. To 
mitigate these risks, MPI has established the Seeds for Sowing import health standard which 
specifies biosec urity measures that must be met before seeds imported for the purpose of 
sowing can be imported into New Zealand. These measures ensure that the likelihood of pests 
and diseases that could cause unwanted impacts entering New Zealand on imported seeds for 
sowing is reduced to a very low level.  
 
1.5 BACKGROUND TO PROPOSED CHANGES TO THE TESTING 
REQUIREMENTS FOR PEPINO MOSAIC VIRUS  IN THE SPECIFIC 
REQUIREMENTS FOR  TOMATO  (SOLANUM LYCOPERSICUM )  
 
(8) Pepino mosaic virus  (PepMV) ( species Pepino mosaic virus ; genus Potexvirus ; family  
Alphaflexiviridae ) is a regulated1 quarantine pest and an unwanted2 organism in New Zealand. 
PepMV mainly infects solanaceous species  such as tomato, capsicum, eggplant  and potato, 
although it is also known to infect several wild and weedy plants from the families 
Amaranthaceae , Asteraceae , Boraginaceae , Brassicaceae , Chenopodiaceae , Convolvulaceae , 
Malvaceae , Plantaginaceae , Polygonaceae  and Solanaceae  (DAWE , 2021).  
 
(9) Tomato is the primary  natural host of PepMV  (CABI , 2021) . Currently, f ive strains of PepMV  
that infect tomato can be distinguished genetically , namely, the  Peruvian strain (LP) (Jones et al, 
1980), the North American  / Chilean strain (US1/Ch1) (Maroon -Lang o et al, 2005; Ling, 2007); 
the European tomato strain (Eu) (van der Vlugt et al. 2000); the Chilean  strain (Ch2) (Ling, 
2007) and the Peruvian wild tomato strain PES (More no-Pérez et al. 2014).  All currently 
 
1 An organism is ‘regulated’ by MPI if the Chief Technical Officer ( CTO) has assessed the organism to be of potential 
importance to New Zealand and not yet present here, or present but not widely distributed and being officially controlled, or  
the organism is a vector for another organism that is regulated. The CTO identifies actions required t o manage any risk of 
entry and establishment from specific regulated organisms.  
 
2 The Biosecurity Act 1993 defines an unwanted organism as ‘ any organism that a chief technical officer believes is capable 
or potentially capable of causing unwanted harm to any natural and physical resources or human health; and  
(a)includes — 
(i)any new organism, if the Authority has declined approval to import that organism;and  
(ii)any organism specified in  Schedule  2 of the Hazardous Substances and New Organisms Act 1996; but  
(b)does not include any organism approved for importation under the Hazardous  Substances  and New Organisms  Act 1996 , 
unless — 
(i)the organism is an organism which has escaped from a containment facility; or  
(ii)a chief tec hnical officer, after consulting the Authority and taking into account any comments made by the Authority 
concerning the organism, believes that the organism is capable or potentially capable of causing unwanted harm to any 
natural and physical resources o r human health .’  
 4 •  Risk Management Proposal – Amendment to the testing requirements for Pepino mosaic virus  Ministry for Primary Industries  identified strains of PepMV, apart from LP, can cause  symptomatic, systemic infection in 
tomato. Symptoms in tomato plants can include marbling, discolouration and splitting of fruit, 
leaf blistering or bubbling, chlorosis and yellow angular leaf spots, severe leaf mosaics and leaf 
and stem necrosi s. These symptoms range in severity, depending on the PepMV  strain  and/or 
variants  present, and the age, vigour and variety of tomato plant, and growing conditions in 
greenhouses. The literature suggests that PepMV does not significantly reduce bulk yields of 
tomato  (although this will depend on tomato variety, strain/variant and growing conditions ). 
However , the quality of the fruit harvested can be reduced significantly  (MPI, 2012) .  
 
(10) PepMV is highly contagious in tomato and is capable of being efficiently transmitted 
mechanically  i.e. through natural or artificial injury of the plant cuticle . It spreads easily  by 
standard crop handling procedures in a glasshouse through contaminated tools, hand s and 
clothing and direct plant -to-plant contact. Invertebrates are also capable of mechanically 
transmitting PepMV. In glasshouse experiments PepMV has been shown to be transmitted 
mechanically by  bumblebees ( Bombus terrestris ). Bumblebees have been shown  to carry 
PepMV when exposed to infected plants (Crop Protection Compendium, 2021; Shipp et al. 
2008)  and have  a widespread distribution in New  Zealand  (NZOR, 2021) . PepMV can also be 
transmitted by the root -infecting parasitic fungus vector Olpidium virulentus  through soil and 
water. Olpidium virulentus  is considered present in New Zealand under the name Olpidium 
brassicae  (MPI, 2012). PepMV has also be en reported to be  transmitted between tomato plants 
by the greenhouse whitefly Trialeurodes vaporariorum  which is also present in New Zealand  
(Noël et al, 2014) .  
 
(11) Infected seed can be a pathway for PepMV  because  it is seedborne and seed -transmitted in 
tomato. Seeds for sowing are considered a high -risk pathway for the introduction of PepM V. 
PepMV  has been detected many times in consignments of traded tomato seeds since 2001. 
Although transmission from contaminate d seeds to seedlings occurs infrequently, at an 
incidence reported to range between 2% and 0.005%, it is believed that transmission via 
contaminated seeds is responsible for initiating outbreaks and for transport of the virus to new 
regions (DAWE 2021, Han ssen and Thomma 2010). Although PepMV is transmitted at a low 
rate, the sheer volume of traded tomato seed for commercial sowing results in a high likelihood 
of spread on this pathway.  The potential economic impacts caused by  PepMV enter ing and 
becoming establish ed in New Zealand have been assessed as low to high . The potential impact  
depend s on factors such as the PepMV  strain, tomato cultivar, environmental factors, and co -
infection with O. virulentus . (MPI, 2012).  
 
(12) MPI i ntroduced requirements in the Standard t o manage the risk from PepMV entering 
New  Zealand on tomato seeds for sowing imported from all countries in 201 2. The requirements 
are: 
• The seeds are produced in a ‘pest -free area’, free from PepMV; or 
• The seeds are produced in a ‘pest -free place of production’, free from PepMV ; or 
• The seeds are officially tested, on a representative sample, and using appropriate 
methods, and found to be free from PepMV.  
 
(13) If testing is the chosen phytosanitary measure, it can be  completed offshore prior to export, or 
on arrival in New Zealand. Pre -export testing for each seed lot must be endorsed by the NPPO 
on the phytosanitary certificate, or if tested on arrival in New Zealand, must be completed by an 
MPI-approved testing laboratory . 
 
(14) In April  and May 2021, PepMV  was detected in tomato plants in four commercial tomato 
growing greenhouse facilities in the Auckland region of New Zealand (MPI, 2021) . Infected 
plants tested positive for the  mild variant of the Ch2 PepMV  strain . MPI and industry partners  
Ministry for Primary Industries   Risk Management Proposal – Amendment to the testing requirements for Pepino mosaic viru s • 5 under the Gove rnment Industry Agreement (GIA) initiated  a joint biosecurity response to 
manage the incursion , which is ongoing . Strict hygiene measures and movement controls are in 
place at the affected properties. Additional surveillance and testing activities are being 
undertaken, including tracing and testing inputs to affected properties. Investigation is ongoing 
to determine the source of the virus in N ew Zealand . While imported tomato seeds for sowing 
have not been determined as the source of the outbreak, they are  a possible source.  
 
(15) Tomato seeds for sowing can be imported into New Zealand from all countries . Between 
January 2018 and December 2020, 899 lines of tom ato seeds for sowing were imported into 
New Zealand in 382 consignments. Seed was imported from 25 countries, including from 
countries where PepMV is known to be present. Almost all N ew Zealand -grown fresh tomato 
produce is grown from imported seed.  
 
(16) The post-border detections of PepMV in New Zealand  in 2021 indicate an increased likelihood 
of the virus entering New Zealand on tomato seeds imported for sowing.  It is important that the 
measures in the Standard are sufficiently robust to ensure that the risk of PepMV entering New 
Zealand on imported tomato seed is reduced to a very low level. One way to gain a higher level 
of assurance that risk is reduced to a lo w level is by specifying testing parameters that provide 
high confidence that low levels of virus on the seeds will be detected by the test.  
 
(17) MPI propose s strengthening the current testing requirements  for PepMV  (currently  “official 
testing on a representa tive sample using appropriate methods ”). We propose  a specif ied seed 
sample size , sampling methodology and  diagnostic testing method that an NPPO may use to 
demonstrate that seeds exported to New Zealand are free from PepMV.  This declaration on 
phytosanita ry certificates will provide increased  assurance that risk is managed appropriately on 
the pathway and will match  the seed testing requirements for  PepMV performed  onshore.  
 
(18) At the time of drafting this risk management proposal , PepMV is a regulated quarantine pest for 
New Zealand . Although there has been an incursion from the Ch 2 strain of PepMV in New 
Zealand , it is currently being officially controlled. If the regulatory status of PepMV or the 
specific Ch2 variant  of PepMV change s during the course of this consultation , this may impinge  
on MPI’s ability to require measures to manage the pest . In this case,  MPI will reconsult 
affected parties on the proposed strengthening of testing requirements for PepMV in the 
Standard . 
2 Proposed change s to the Standard  
 
(19) MPI proposes a change to the testing requirement for PepMV  in the specific requirements for  
tomato  (Solanum lycopersicum ) in the Standard  to require that see ds are “officially tested, on a 
representative sample of a minimum of 3 ,000 seeds officially drawn according to the ISTA or 
AOSA sampling methodology, using an NPPO -approved ELISA or NPPO -approved PCR 
testing method and found free from Pepino mosaic virus ”. The change as it will appear on the 
Standard can be found in Appendix 1 of this risk management proposal . 
2.1 NON -REGULATORY CHANGES TO THE STANDARD  
 
(20) MPI has included guidance in the specific requirements for Solanum lycopersicum  in the Standard 
to state that:  
 
(i) MPI does not accept  bioassay s to detect the presence of PepMV  on seed samples .  6 •  Risk Management Proposal – Amendment to the testing requirements for Pepino mosaic virus  Ministry for Primary Industries   
(ii) Additional declarations on phytosanitary certificates to meet the offshore testing 
requirements for PepMV  in the import health standard Seeds for Sowing  should be 
based only on a negative result obtained in an NPPO -approved ELISA or NPPO -
approved PCR and not on results from a bioassay.  
 
(21) None of these  non-regulatory  changes alter the intent of or the requirements within the 
Standard. The inclusion of guid ance is considered a minor amendment  in accordance with 
section 24B(2)  of the Act and , as such , do not require consultation under section  23(2) of the 
Act. Please note that these minor amendments have  only been included for clarity and 
transparency purpose s, and they do not  form part of the consultation . The inclusions in guidance 
as they will appear in the Standard can be found in Appendix 1 of this risk management 
proposal . 
3 Rationale for the proposed change to the Standard  
3.1 PROPOSED CHANGE TO THE TESTING REQUIREMENTS FOR PE PINO 
MOSAIC VIRUS  
 
(22) For tomato seeds for sowing imported into New Zealand that are tested before export, MPI 
gains assurance that seeds are free from PepMV by the exporting country NPPO endorsing the 
measure in an additional decla ration on the phytosanitary certificate. MPI propose s an 
amendment to the current additional declaration for PepMV  to prescribe  a seed sample size for 
testing  (3,000 seeds) , seed sampling methodology  (ISTA or AOSA methodology) and a 
diagnostic test ing method  (NPPO -approved ELISA or PCR) .  
 
(23) PepMV was the first quarantine pest on tomato seed for which specific measures were 
introduced in the Standard in 2012. Prior to this, tomato seeds for sowing were eligible to 
import into New Zealand under basic requ irements. The additional declaration for seed testing 
for PepMV in the Standard was modelled on the declaration on phytosanitary certificates that 
was required by the European Union for tomato seeds originating in non-EU c ountries.  
 
(24) Since introdu cing measures for PepMV, MPI ha s regulated other quarantine viruses on tomato 
seeds for sowing in  the Standard , with more prescriptive requirements . For example, for Tomato 
mottle mosaic virus , testing is to be performed on a representative sample of a minimum of 
3,000 seed s drawn according to ISTA or AOSA methodology using an NPPO -approved ELISA 
or NPPO -approved  PCR testing method. MPI has concluded  that the testing requirement s for 
PepMV should be  aligned in  their strength and specificity with viruses of a similar risk profile . 
  
(25) PepMV is a seedborne pathogen, and it can be detected by testing a representative sample from 
a seed lot. Sampling of the seed lot performed according to ISTA or AOSA methodology will 
ensur e that the sample drawn for testing accurately  reflects the characteristics of the whole seed 
lot (International Rules for Seed Testing, 2021) . A 3,000-seed sample is a suitable sample size 
for testing for the presence of PepMV. Testing a representative sample of 3 ,000 seeds , drawn 
from a large, well -mixed seed lot, will detect pest infestation at levels as low as 0.1% with 95% 
confidence  (FAO, 2008 ). The  prevalence of virus pests in seed lots is assumed to be at 0.1%. 
Testing a 3 ,000-seed sample is in line with the sample size requirements for testing for other 
quarantine viruses such as tomato brown rugose fruit virus and tomato mottle mosaic virus in 
the specific requirements for  tomato  (Solanum lycopersicum ) in the Standard.  
  
Ministry for Primary Industries   Risk Management Proposal – Amendment to the testing requirements for Pepino mosaic viru s • 7 (26) Molecular (PCR) and serological (ELISA) diagnostic methods are routinely used to detect 
seedborne pests . Both methods are sensitive for detecting specific viruses, including PepMV . 
Both ELISA and PCR tests are developed for testing for PepMV. The European Plant Protection 
Organi zation (EPPO) recommends both ELISA and PCR tests for detecting and identifying 
PepMV on tomato seeds  (EPPO, 2013) . For qualitative detection and identification of PepMV, 
double antibody sandwich ELISA (DAS -ELISA) is recommended as the initial test of choice. 
Real-time reverse transcription PCR (real -time RT -PCR) is recommended as the  molecular test 
of choice.  The ELISA and PCR diagnostic protocols for PepMV are both based on a 
recommended minimum sample size of 3 ,000 seeds with a maximum sub -sample size of 250 
seeds and are both able to detect one infected seed in a sub -sample of 250 seeds  (EPPO, 2013).  
 
(27) Amending the testing requirements for PepMV to specify a sample size (3 ,000 seeds), sampling 
methodology (ISTA or AOSA sampling) and testing method (PCR or ELISA) will align the 
offshore testing requirements with the onshore testing requirements for PepMV. Currently, 
onshore testing is performed by the MPI Plant Health and Env ironment Laboratory on a tomato 
seed sample of 3,000 seeds, officially drawn using ISTA methodology, using a real -time RT -
PCR assay. PHEL’s accredited PepMV assay i s based on primers designed by Ling et al. (2017 ) 
and is in accordance with the recommended PCR diagnostic protocol in the EPPO diagnostic 
standard for PepMV.  
3.2 INCLUSION OF GUIDANCE REGARDING THE USE OF A BIOASSAY IN SEED 
TESTING FOR THE PRESENCE OF PEPINO MOSAIC VIRUS  
 
 
(28) MPI does not accept the use of a bioassay to detect PepMV in tomato seed samples exported to 
New Zealand. This guidance has been included in the Stan dard to clarify the phytosanitary 
requirements concerning offshore testing of tomato seeds for sowing for the presence of PepMV  
and to facilitate compliance with these requirements by importers, exporters and exporting 
countr ies’ NPPOs .  
 
(29) Bioassay results  do not provide  New Zealand with an  appropriate level of protection against  
PepMV on imported tomato seeds for sowing. This guidance is included in the Standard 
because there are certain diagnostic protocols that rely on a bioassay on susceptible herbaceous  
indicator plants to draw conclusions on whether a seed lot is infected with PepMV. For 
example, the International Seed Health Initiative for Vegetable Crops (ISHI -Veg) has published 
a diagnostic protocol for detect ing PepMV on tomato seeds usin g ELISA  that relies on a 
bioassay  (ISHI-Veg, 2021).  The ISHI -Veg protocol approves two bioassay methods for 
detecting infectious PepMV  in tomato seed extracts. MPI does not approve of either of these 
methods.  
i. In the first method,  Nicotiana benthamiana  plants  are inoculated  and then ELISA  is 
conducted on  the new non -inoculated leaves of the plant to confirm the presence of 
systemic infect ion by PepMV.  
 
ii. In the second method,  ELISA is used on seed extracts as a pre -screen.  
- If the pre-screen by ELISA  does not detect  PepMV , the protocol con cludes  that the 
seeds are free from the virus .  
- If the pre -screen by ELISA detect s PepMV , the protocol involves  using  a bioassay to 
confirm the presence of infectious PepMV. If no symptoms are observed in the 
bioassay , the protocol  concludes that seeds are free from PepMV .  
- If symptoms are observed in the bioassay , the protocol involves  confirmat ion by  
ELISA. If the results of this confirmatory ELISA  detect s PepMV , then the seed lot is 8 •  Risk Management Proposal – Amendment to the testing requirements for Pepino mosaic virus  Ministry for Primary Industries  considered infected with PepMV.  
- If the confirmatory ELISA does not detect  PepMV , the protocol concludes  that the 
seed lot is free from the virus , despite the positive result obtained in the initial pre -
screen ELISA . The protocol concludes  that the pre -screen ELISA identified 
biologically inactive PepMV .  
 
(30) The EPPO diagnostic standard recommends DAS -ELISA as the initial test of choice for 
qualitative detection and identification of PepMV . It does  not recommend a bioassay  as a test 
for detecting PepMV in seeds (EPPO, 2013).  Bioassay s are less sensitive  than ELISA s and are 
more  prone to variability and false negatives. The two methods , as described above , are prone to 
false negative results  at low incidence of infected seed. This mean s tomato seeds that are 
infected with PepMV  and tested with either of these methods  could be passed as healthy and  be 
approved for export.  
 
(31) MPI has concluded that  the advice of the EPPO, that a bioassay is not recommended for 
detecting PepMV in seeds , is suitable for the New Zealand context . 
4 Feasibility of the proposed change to the Standard  
 
(32) Procedures  for detectin g and identif ying PepMV in a representative sample from a tomato seed 
lot comprising 3 ,000 seeds using ELISA and PCR methods are available for exporting NPPOs 
to use for pre -export testing.  The NPPOs of exporting countries  routinely certify  tomato seeds 
for export to New Zealand as free from PepM V based on  seed testing for PepMV by ELISA or 
PCR. This amendment brings the wording of the additional declaration in line with the 
declarations required for other quarantine pests of tomato in the S tandard.  
 
(33) ELISA and PCR diagnostic protocols for detect ing and identif ying PepMV on tomato seed have 
been available for more than 10 years . These protocols are published, validated and have been 
used internationally for phytosanitary testing of seed. The EPPO Standard (PM 7/113 (1) 
Pepino mosaic virus ), first published in April 2013 describes a diagnostic protocol for detection 
of PepMV in tomato seeds using DAS -ELISA and real -time RT -PCR. MPI recognises the ISHI -
Veg diagnostic protocol “Detection of Pepino mosaic virus  in tomato seeds ” as effective for 
detect ing and identify ing PepMV on tomato seeds, as long as the method is not used in 
conjunction with a bioassay.  
 
(34) DAS -ELISA kits containing all necessary components n eeded for the test are widely available 
commercially and can be used  in the diagnostic protocol described in the EPPO Standard PM 
7/113 (1) . Commercial antisera against PepMV that detect all known strains of PepMV  are 
included in these kits that are available worldwide , for example from Prime Diagnostics and 
Bioreba  (Prime Diagnostics 2021; Bioreba 2021) .  
 
(35) PCR primers and probes have been published for a highly sensitive and specific  real-time RT -
PCR assay  in Ling et al 2007. PCR testing of tomato se eds for phytosanitary certification using 
this assay has been adopted by  exporting NPPOs such as Australia , as well as by PHEL for 
onshore testing of tomato seeds  for PepMV  for import and export certification .  
 
(36) Allowing both ELISA and PCR will be trade -enabling. The EPPO standard for seed health 
testing for PepMV recommends both DAS -ELISA and real -time RT -PCR -based assays. Several  
tomato  seed-producing countries exporting to the EPPO region are likely to be using  either of 
these methods to test their tomato seeds for export. Re-export is integral to the international  
Ministry for Primary Industries   Risk Management Proposal – Amendment to the testing requirements for Pepino mosaic viru s • 9 movement of seeds , and Europe is a key destination from which tomato seeds are re -exported to 
New Zealand. Given the acceptance of ELISA and PCR testing of tomato seeds exported to the 
Europ ean Union for PepMV, it could become trade -restrictive if New Zealand only specif ies 
PCR testing as a requirement , which would necessitate retesting seed lots already tested by 
ELISA and certified as free from PepMV. Tomato seeds are often imported into New  Zealand 
in shipments comprising low volumes of seed. Requiring PCR for PepMV of se ed shipments to 
New Zealand  that may have already been tested by ELISA could lead to destruction of a 
significant proportion of seeds in the shipment, which could become prohibitive to importers.  
 
(37) The proposed testing requirements for PepMV align with the sample sizes for testing for other 
quarantine virus and viroid pests of  tomato seed in the Standard , namely , Columnea latent 
viroid , Potato spindle tuber viroid , Tomato chlorotic dwarf viroid , Tomato brown rugose fruit 
virus , Tomato apic al stunt viroid , Tomato planta macho viroid  and Tomato mottle mosaic virus . 
PCR is a common option for all these pests , and it is likely that testing for all these pests can be 
done on a single  sample of 3 ,000 seeds with a maximum subsample size of 250 seeds  (or 400 
seeds if the seeds do not need to be tested for tobamoviruses) . Therefore, at a minimum a total 
of 3,000 seeds needs to be sacrificed per tomato seed lot for testing for all the quarantine pests 
in the Standar d. 
 
(38) Onshore testing for PepMV  at PHEL is routinely performed using PCR. The indicative cost of 
RT-PCR testing of a sample of 3,000 untreated seeds for PepMV  onshore at PHEL  is NZ $1,020 
(excl. GST). This testing would be done on 12 subsamples of 250 seeds each. However, seeds 
normally received by PHEL for testing for PepMV also require testing for the other quarantine 
pests of tomato seed in the Standard. PHEL can combine test ing efficiencies for PCR  testing for 
PepMV and the pospiviroids ( Columnea latent viroid, potato spindle tuber viroid, tomato 
chlorotic dwarf viroid, tomato apical stunt viroid and tomato planta macho viroid ) by testing 
3,000 seeds as subsamples of up to 400 seeds, i.e. eight  subsa mples at the cost of $720 (excl. 
GST). However, if the seeds also need to be tested for Tomato brown rugose fruit virus  and 
Tomato mottle mosaic virus , the testing is done on 12 subsamples of 250 seeds each.  On the 
other hand, the indicative cost of an ELISA assay is NZ $650 (excl. GST).  Note that PHEL do es 
not currently offer onshore  seed testing for PepMV by ELISA.  
  10 •  Risk Management Proposal – Amendment to the testing requirements for Pepino mosaic virus  Ministry for Primary Industries  5 References  
Bioreba AG  (2021)  Startseite.  http://www.bioreba.com/  Accessed 29 August 2021.  
Blystad, D -R; van der Vlugt, R; Alfaro -Fernández, A; del Carmen Córdoba, M; Bese, G; Hristova, D; 
Pospieszny, H; Mehle, N; Ravnikar, M; Tomassoli, L; Varveri, C; Nielsen , S L (2015) Host range and 
symptomatology of  Pepino mosaic virus  strains occurring in Europe. European Journal of Plant 
Pathology 143(1): 43 –56. 
CABI (2021) Pepino mosaic virus . Crop Protection Compendium . 
https://www.cabi.org/isc/datasheet/43661  Accessed 27 August 2021.  
DAWE (2021) Final pest risk analysis for Pepino mosaic virus and pospiviroids associated with 
tomato seed. Australian Government, Department of Agriculture, Water and the Environmen t. Feb 
2021.  
EPPO (2013). EPPO Standard (PM 7/113 (1) Pepino mosaic virus). https://doi.org/10.1111/epp.12023  
Accessed 29  August 2021 . 
FAO (2008) International Standards for Phytosanitary Measures (ISPM) No. 31. Methodologies for 
sampling of consignments . Secretariat of the International Plant Protection Convention, Food and 
Agricultural Organization of the United Nations; Rome, Italy.  
Hanssen, I M;  Paeleman, A; Wittemans, L; Goen, K; Lievens, B; Bragard, C; Vanachter, A C R C; 
Thomma, B P H J (2008) Genetic characterization of Pepino mosaic virus  isolates from Belgian 
greenhouse tomatoes reveals genetic recombination. European Journal of Plant Patho logy 121(2): 
131–146. 
Hanssen, I M; Thomma, B P H J (2010) Pepino mosaic virus: a successful pathogen that rapidly 
evolved from emerging to endemic in tomato crops. Molecular Plant Pathology  11(2): 179 –189.  
https://www.agriculture.gov.au/biosecurity/risk -analysis/plant/pepino -mosaic -virus -pospiviroids -
tomato -seed 
ISHI -Veg (2021) Detection of Pepino mosaic virus  in Tomato Seed . International Seed Health 
Initiative for Vegetable Crops  (ISHI -Veg). International Seed Federation; Nyon, Switzerland. 
https://www.worldseed.org/wp -content/uploads/2021/03/Protocol_Tomato_PepMV_v5_March -2021 -
1.pdf  Accessed 29 August 2021.  
ISTA  (2021) Chapter 2: Sampling . International Rules for Seed Testing 2021.  International Seed 
Testing Association; Bassers dorf, Switzerland.  
https://www.seedtest.org/upload/cms/user/s4_ISTA_Rules_2021_02_sampling.pdf  Accessed 27 
August 2021.  
Jones, R A C; Koenig, R; Lesemann, D E (1980) Pepino mosaic virus,  a new potexvirus from pepino 
(Solanum muricatum ). Annals of Applied Biology 94(1): 61 –68. 
Ling KS, Wechter WP, Jordan R. (2007). Development of a one -step immunocapture real -time 
TaqMan RT -PCR assay for the broad -spectrum detection of Pepino mosaic virus. Journal of 
Virological Methods 144: 65–72.  
Ling, K -S (2007) Molecular characterization of two Pepino mosaic virus  variants from imported 
tomato seed reveals high levels of sequence identit y between Chilean and US isolates. Virus Genes 
34(1): 1 –8. 
MAF; MFAT; FSA  (2009) Balance in Trade.  Ministry of Agriculture and Forestry, Ministry of 
Foreign Affairs and Trade, New Zealand , Food Safety Authority ; Wellington , NZ. 
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Maroon -Lango, C J; Guaragna, M A; Jordan, R L; Hammond, J; Bandla, M; Marquardt, S K (2005) 
Two unique US isolates of Pepino  mosaic virus  from a limited source of pooled tomato tissue are 
distinct from a third (European -like) US isolate. Archives of Virology 150(6): 1187 –1201.  
Moreno -Pérez, M G; Pagán, I; Aragón -Caballero, L; Cáceres, F; Fraile, A; García -Arenal, F (2014) 
Ecolo gical and genetic determinants of Pepino mosaic virus emergence. Journal of Virology 88(6): 
3359 –3368.   
Ministry for Primary Industries   Risk Management Proposal – Amendment to the testing requirements for Pepino mosaic viru s • 11 MPI (2012) Import Risk Analysis: Tomato and capsicum seed for sowing from all countries.  
https:/ /www.mpi.govt.nz/dmsdocument/2887  Accessed 27  August 2021.  
MPI (2021) Pepino mosaic virus (PepMV) in Auckland . Ministry for Primary Industries; Wellington, 
NZ. https://www.mpi.govt.nz/biosecurity/major -pest-and-disease -threats/pepino -mosaic -virus -pepmv -
in-auckland/  Accessed 27 August 2021.  
Noël,  P; Hance, T; Bragard, C (2014) Transmission of the Pepino mosaic virus  by whitefly. European 
Journal of Plant Pathology 138(1): 23 –27. 
NZOR (2021) The New Zealand Organisms Register. http://nzor.org.nz  Accessed 29 August  2021.  
Prime Diagnostics (2021) https://www.wur.nl/en/show/Prime -Diagnostics -2.htm  Accessed 29/08/2021  
Shipp, J L; Buitenhuis, R; Stobbs, L; Wang, K; Kim, W S; Ferguson, G (2008) Vectoring of Pepino 
mosaic virus  by bumble -bees in tomato greenhouses. Annals of Applied Biology 153(2): 149 –155. 
Spence, N J; Basham, J; Mumford, R A; Hayman, G; Edmondson, R; Jones, D R (2006) Effect of 
Pepino mosaic virus on the yield and quality of glasshouse -grown tomatoes in the UK. Plant 
Pathology 55(5): 595 –606. 
van der Vlugt, R A A; Stijger, C C M M; Verhoeven, J T J; Lesemann, D -E (2000) First report of 
Pepino mosaic virus  on tomato. Plant Disease 84(1): 103 –103. 
  12 •  Risk Management Proposal – Amendment to the testing requirements for Pepino mosaic virus  Ministry for Primary Industries  6 Appendix  1 
 
 
 
 
 
 
 
 
Ministry for Primary Industries   Risk Management Proposal – Amendment to the testing requirements for Pepino mosaic viru s • 13  
 
 
 
 
 
 
 
14 •  Risk Management Proposal – Amendment to the testing requirements for Pepino mosaic virus  Ministry for Primary Industries