Risk Management Proposal:  
Proposed Amendments to the Specific 
Requirements for Cannabis sativa , 
Capsicum , Chrysanthemum coronarium , 
Petunia , Phaseolus , Pisum , Solanum 
lycopersicum  and Vicia  in Import Health 
Standard Seeds for Sowing (155.02.05)  
 
 
 
 
 
 
 
 
 
 
 
Prepared for  public consultation   
by Plant Germplasm Imports  
Animal and Plant Health Directorate  
 
April 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 Primary Industries   
i Contents  Page 
 
Submissions  1 
1 General information  3 
1.1 Purpose  3 
1.2 Background  3 
1.3 Timing of consultation  3 
1.4 General context of consultation  3 
1.5 Background for proposed changes to testing requirements for Tomato brown rugose 
fruit virus  on Capsicum  sp. and Solanum lycopersicum  seeds for sowing  4 
1.6 Background for proposed changes to pest lists  5 
1.7 Background for proposed requirements for Potato spin dle tuber viroid  (PSTV d) on 
Chrysanthemum coronarium and Petunia  seed  6 
1.8 Information sources  7 
2 Proposed changes to the Standard  8 
2.1 Proposed removal  of elisa as a testing option for tomato bro wn rugose fruit virus on 
capsicum sp. and solanum lycopersicum seeds for sowing  8 
2.2 Proposed requirements for Hemp mosaic virus and Hemp streak virus on Cannabis 
sativa  8 
2.3 Proposed requirements for Artichoke yellow ringspot virus  on Phaseolus  8 
2.4 Proposed requirement s for Pea enation mosaic virus  on Pisum  and Vicia  9 
2.5 Proposed requirements for Peanut stunt virus  on Phaseolus  and Vicia  9 
2.6 Proposed requirements for Potato spindle tuber viroid on Chrysanthemum  coronarium  
and Petunia sp. 10 
3 Rationale for the proposed changes to the Standard  11 
3.1 Removal of ELISA as a testing option for  Tomato brown rugose fruit virus  on Capsicum  
sp. and Solanum lycopersicum seeds for sowing  11 
3.2 Non-viral nature of Hemp mosaic virus and Hemp streak virus on Cannabis sativa  12 
3.3 Host status of Phaseolus  for Artichoke yellow ringspot virus  13 
3.4 Seed transmission of Pea enation mosaic virus  on Pisum  and Vicia  13 
3.5 Seed transmission of Peanut stunt virus  on Phaseolus  and Vicia  13 
3.6 Rationale for the proposed requirements for Potato spindle tuber viroid on 
Chrysanthemum  coronarium  and Petunia sp. 14 
4 Feasibility of the proposed changes to the Standard  16 
4.1 Proposed removal of ELISA as a testing option for Tomato brown rugose fruit virus  on 
Capsicum  sp. and Solanum lycopersicum seeds for sowing  16 
4.2 Proposed removal of measures for Hemp mosaic virus and Hemp streak virus on 
Cannabis sativa  seed for sowing  17 
4.3 Proposed removal of measures for Artichoke yellow ringspot virus  on Phaseolus  17 
4.4 Proposed removal of measures for Pea enation mosaic virus  on Pisum  and Vicia  18 
4.5 Proposed removal of measures for Peanut stunt virus  on Phaseolus  and Vicia  18 
4.6 Feasibility of the proposed requirements for Potato spindle tuber viroid on 
Chrysanthemum  coronarium  and Petunia sp. 19 
5 References  20 
6 Appendices  22 
6.1 Illustration of proposed changes applied to the Standard  22 ii 
 6.2 Technical advice on whether Phaseolus  spp. is a natural host of Artichok e yellow 
ringspot virus (AYRSV), and seed transmission of Hemp mosaic virus and Hemp 
streak virus on Cannabis sativa  43 
6.3 MPI technical assessment: seed transmission of Pea enation mosaic virus  (PEMV) on 
Pisum  sp. and Vicia  sp. and Peanut stunt virus (PSV) on Phaseolus  sp. and Vicia  sp.
 46 
6.4 Scientific and technical advice on whether measures are required to manage the risk 
from Potato spindle tuber viroid  (PSTV d) on seed for sowing of the ornamental species 
Dahlia, Ch rysanthemum and Diascia , eligible to import under IHS 155.02.05: S eeds for 
Sowing  50 
  
Ministry for Primary Industries   RMP: Proposed Amendments to Seed for Sowing IHS  • 1 Submissions  
The Ministry for Primary Industries (MPI) invites comment from interested parties on 
proposed amend ments to the  Import Health Standard 155.02.05: Seeds for Sowing  (the 
Standard) .  
 
An import health standard (IHS) “specifies requirements to be met for the effective 
management of risks associated with importing  risk goods” (section 22 Biosecurity Act 
1993).  
 
MPI is seeking comment on the following proposed changes to the Standard:   
• Removal of ELISA as a testing  method for Tomato brown rugose fruit virus  on 
Capsicum  sp. and Solanum lycopersicum seeds for sowing from all countries .  
• Removal of Hemp streak virus  and Hemp mosaic virus  from the pest list for 
Cannabis sativa , and removal of measures for these pests  on Cannabis sativa  
seeds for sowing from all countries . 
• Removal of Artichoke yellow ringspot virus from the pest list for Phaseolus  sp., 
and removal of measures for this pest on Phaseolus  sp. seeds for sowing from all 
countries . 
• Removal of Pea enation mosaic virus  from the pest lists for Pisum  sp. and Vicia  
sp., and removal of measures for this pest on  Pisum  sp. and Vicia  sp. seed for 
sowing from all countries . 
• Removal of Peanut stunt virus  from the pest lists for Phaseolus  sp. and Vicia  sp., 
and removal of measures for this pest on Phaseolus  sp. and Vicia  sp. seeds for 
sowing from all countries . 
• Addition of requirements for Potato spindle tuber viroid  (PSTVd) on Glebionis 
coronaria (synonym Chrysanthemum coronarium ) and Petunia sp. seeds for 
sowing.  
 
MPI encourages respondents to forward comments electronically. Please include the 
following in you r submission:  
• The title of the consultation document in the subject line of your email;  
• Your name and title (if applicable);  
• Your organisation’s name (if applicable); and  
• Your address.  
 
Send submissions to plantimports@mpi.govt.nz . 
 
However, should you wish to forward submissions in writing (hard copy), please send them to 
the following address to  arrive by close of business on 21 May 2021 :  
 
Plant Germplasm Imports  
Animal and Plant Health  Directorate  
Biosecurity New Zealand  
Ministry for Primary Industries  
PO Box 2526  
Wellington 6140  
New Zealand  2 • RMP: Proposed Amendments to Seed for Sowing IHS  Ministry for Primary Industries   
Submissions received by the closure date will be considered during the development of the 
final standard . Submissions received after the closure date may be held on file for 
consideration when the issued 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 request s for information under the Official Information Act 1982 (OIA). The OIA 
specifies that information is to be made available 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 that is  
commercially sensitive or personal. Any decision to withhold information requested under the 
OIA is reviewable by the Ombudsman . 
 
 
   
Ministry for Primary Industries   RMP: Proposed Amendments to Seed for Sowing IHS  • 3 1 General information  
 
1.1 Purpose  
(1) The purpose of this document is to:  
• Provide relevant background information about the Import Health Standard 
155.02.05: Seeds for Sowing  (the Standard) ; 
• Outline a set of proposed changes to the  testing requirements for Tomato brown 
rugose fruit virus  on Capsicum  spp. (capsicum)  and Solanum lycopersicum  
(tomato) seeds for sowing required by the Standard ; 
• Outline a set of proposed changes to the  regulated pest lists for Cannabis sativa , 
Phaseolus , Pisum , and Vicia  seed listed in the Standard ; 
• Outline a set of proposed changes adding requirements for Potato spindle tuber 
viroid  on Chrysanthemum coronarium  and Petunia sp.; 
• Provide the rationale for the proposed changes to the Standard ; and  
• Seek feedback on the proposed Standard . 
 
(2) The subject of public consultation is the specific amendments proposed in the draft 
Standard. This risk management proposal supports the draft Standard and should be 
read in full, and in conjunction with the draft standard, to understan d the rationale 
behind the proposed import requirements. The risk management proposal itself is not 
the subject of public consultation  
 
1.2 Background   
(3) 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 foreign countries and 
territories . 
 
1.3 Timing of consultation  
(4) The proposed changes to the Standard were released for consultation on 20 April 
2021  and will remain open for consultation until 21 May 2021 . 
 
1.4 General context of consultation  
 
1.4.1 International regulation of risk goods  
(5) The World Trade Organi zation Agreement on the Application of  Sanitary and 
Phytosanitary Measures (the 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 scien ce-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. 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 demonstrate that 
New Zealand’s strict controls are just ified to countries that challenge them. ” (MPI, 
2009 ) 
 4 • RMP: Proposed Amendments to Seed for Sowing IHS  Ministry for Primary Industries  1.4.2 Domestic regulation of biosecurity risks associated with seeds for sowing  
(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 an import health standard . 
MPI is the N ew Zealand  government ministry responsible for maintaining biosecurity 
standards for the effective management of risks asso ciated with the importation of risk 
goods into N ew Zealand  (Part 3, Biosecurity Act 1993). MPI is committed to the 
principles of transparency and evidence -based technical justification for all 
phytosanitary measures, new and amended, imposed on importing p athways.  
 
 
1.5 Background  for proposed changes to testing requirements for Tomato brown 
rugose fruit virus  on Capsicum  sp. and Solanum lycopersicum  seeds for 
sowing  
(7) Tomato brown rugose fruit virus  (TBRFV/ToBRFV )1 (Tobamovirus: Virgaviridae) is 
a regulated quarantine pest of concern that is not known to be present in New Zealand 
(Official New Zealand Pest Register, 2020). TBRFV  causes natural infection in its 
major hosts tomato ( Solanum lycopersicum ) and capsicum ( Capsicum annuum ) 
(EPPO, 2020  a). It is an unwanted organism , which,  if introduced to New Zealand , 
could have unwanted impacts  on New Zealand’s tomato and capsicum indu stries.  
 
(8) TBRFV can be associated with seed s. The virus is efficiently transmitted 
mechanically , but it has a low transmission rate from seed to seedling (1.8 -2.8%)  
(Davino et al., 2020) . TBRFV is highly stable and can persist in the environment for 
many years. The virus can cause 30 -70% loss of tomato yield, reducing plant vigour  
and the length of the production period during which fruits are harvested, as well as 
fruit quality (EPPO , 2020  b). 
 
(9) Seeds for sowing are considered a high -risk pathway for the introduction of TBRFV. 
The high potential risks associated with the introducti on of TBRFV into a new area 
are attributed mainly to the virus’s stability and high infectivity, through to 
mechanical transmission by workers, tools and equipment during handling of infected 
plants.  TBRFV was first reported in 2014 from southern Israel. T he virus further 
spread in Israel across the entire country within one year through human -assisted 
spread and local trade of infected seeds or seedlings. By 2020, TBRFV was reported 
to have spread to a number of countries including Germany, China, Turkey, Italy, the 
UK, Netherlands, Greece, Spain and France (Crop Protection Compendium, 2020).  
 
(10) MPI implemented emergency measures for TBRFV on tomato and capsicum seeds for 
sowing in March 2019, as the likelihood of introduction on these pathways to cause 
unacceptable economic and social impacts to New Zealand was considered  high. The 
following meas ures were required:  
• Sourcing seeds from a ‘pest -free area’, free from TBRFV, or  
• Sourcing seeds from a ‘pest -free place of production’, free from TBRFV, or  
• Official testing for TBRFV on a representative sample of a minimum of 3,000 seed s 
drawn according to  ISTA or AOSA methodology, using an NPPO -approved 
enzyme -linked immunosorbent assay (ELISA)  testing method.  
 
 
1 Both TBRFV and ToBRFV are commonly used abbreviations for Tomato brown rugose fruit virus . This Risk Management 
Proposal uses the abbreviation TBRFV.   
Ministry for Primary Industries   RMP: Proposed Amendments to Seed for Sowing IHS  • 5 (11) At the time these measures were introduced , there was a validated ELISA t est for 
TBRFV available for exporting national plant protection organisations ( NPPOs ) to use 
to test capsicum and tomato seeds for export to N ew Zealand . Polymerase chain 
reaction ( PCR ) assays  for the virus  were still being developed and validated  at the 
time. Therefore, testing using ELISA  was considered a feasible risk management 
measure  for TBRFV.  
 
(12) In 2020, MPI added to the Standard the option of testing tomato and capsicum seeds 
for TBRFV using an NPPO -approve d PCR test , because  sensitive and specific 
validated PCR assays for detectin g and identif ying TBRFV in seed samples had been 
developed.  
 
 
(13) The ELISA testing  option for TBRFV in the Standard is not currently considered to 
provide an appropriate level of protection from the virus. There is current awareness 
that PCR tests (RT-PCR and RT -qPCR2) are more sensitive and specific for detecti ng 
TBRFV than ELISA. Furthermore,  the likelihood of entry of TBRFV on the capsicum 
and tomato seed import pathways is  considered high . There were  two post -border 
detections of TBRFV on capsicum and tomato seeds for sowing that were imported 
into New Zealand  in 2020 . The first post -border detection was on a capsicum seed lot 
destined for re -export . None of the contaminated seeds entered the New Zealand 
market , and all the seeds were destroyed. The second post -border detection  was on a 
tomato seed  lot that entered the New Z ealand market . Seed samples from this lot 
tested positive for a low titre of virus . This incursion  resulted  in a joint MPI –GIA 
biosecurity  response  being undertaken  to eliminate the virus , as entry of low levels of 
the virus were deemed a biosecurity risk for New Zealand.   
 
(14) Following the TBRFV incursion and response, MPI propose d strengthen ing its 
phytosanitary import requirements for TBRFV on capsicum and tomato seeds for 
sowing. The post-border detections of the vi rus in 2020 indicate  an increased 
likelihood of entry of the virus into New Zealand on commercial capsicum and tomato 
seed for sowing imports. Given the serious risk that TBRFV pose s to New  Zealand’s 
capsicum and tomato industries, it  is important that measures in the Standard  provide a 
high level of assurance  that seeds imported on these pathways are free from even low 
levels of the virus.  
 
(15) MPI propose s strengthen ing its import requirements to manage biosecurity risk from 
TBRFV on th e capsicum and tomato seeds for sowing import pathways by removing 
ELISA as a testing option and requiring that official testing of imported consignments 
is performed using an NPPO -approved PCR testing method.  
 
 
1.6 Background  for proposed changes to pest lists  
(16) The International Standard for Phytosanitary Measures 38 (ISPM 38 ) is the 
international standard that covers  the international movement of seeds and provides 
detailed guidance for the commodity class “seeds  for planting” (known as “seeds for 
sowing” in the Standard).  ISPM 38 was issued by the International Plant Protection 
 
2 Because TBRFV is an RNA -virus, a reverse transcription PCR assay is required to detect the virus. In this Risk Management 
Proposal, ‘PCR’ refers to a reverse transcription PCR assay for TBRFV. This can be undertaken as an endpoint reverse 
transcription PC R (RT -PCR) or as a real -time quantitative reverse -transcription PCR (RT -qPCR).  6 • RMP: Proposed Amendments to Seed for Sowing IHS  Ministry for Primary Industries  Convention (IPPC) to provide agreed guidelines and principles for countries to 
implement phytosanitary measures and procedures.  
  
(17) New Zealand is a contracting party  to IPPC, and supports coordinated, effective action 
to prevent and control the introduction and spread of pests of plants and plant 
products. In keeping with New Zealand’s obligations under the SPS Agreement and 
the IPPC (International Plant Protection Convention), phytosanitary measures must be 
scientifically justified and only for regulated pests.  
 
(18) With the adoption of ISPM 38 (IPPC, 2020) on the international movement of seeds 
for sowing, the national plant protection o rganisation ( NPPO ) of the Netherlands has 
begun reviewing the import requirements placed on seeds they export. The focus of 
their review was whether there is sufficient evidence of seed transmission for the 
organisms requiring import measures.  
 
(19) Following t heir review, the NPPO of the Netherlands concluded that some of the 
regulated pests requiring measures in the Standard are not seedborne or seed -
transmitted. For these pests, they have corresponded with MPI, providing technical 
information on host and pest  transmission status and requesting that MPI provide the 
rationale for why the organism is regulated. They have also requested that the 
organisms be removed from the import requirements for seeds where evidence 
indicates regulation is not justified.  
 
(20) MPI h as considered the technical information in the letters from the Netherlands ’ 
NPPO, and additional scientific reports related to the pests, to assess whether the 
current import requirements for these organisms in the Standard are justified. After 
assessing this evidence, MPI considers  that continued regulation of some of the pests 
identified by the NPPO of the Netherlands is unjustified and that the Standard should 
be amended to remove  requirements for these organisms after public consultation.  
 
(21) The requirements MPI is proposing to remove from the Standard relate to:  
• Hemp streak virus  and Hemp mosaic virus  on Cannabis  sativa   
• Artichoke yellow ringspot virus  (AYRSV) on Phaseolus  
• Pea enation mosaic virus  (PEMV) on Pisum  and Vicia  
• Peanut stunt virus  (PSV) on Phaseolus  and Vicia  
 
 
1.7 Background for proposed requirements for Potato spindle tuber viroid  
(PSTV d) on Chrysanthemum coronarium and Petunia  seed  
(22) MPI risk assessment provided scientific and technical advice on potential seed 
transmissibility of PSTVd in several ornamental species. It was found that PSTVd is 
seed-transmitted and pollen -transmitted in Petunia  x hybrida  and seed -transmitted in 
Glebionis coronaria  (the acc epted name of the synonym Chrysanthemum 
coronarium ). 
 
(23) The risk associated with PSTVd on Chrysanthemum  coronarium  and Petunia  is being 
considered  here for the seeds for sowing pathway only, because  the plants for planting 
pathway for these species  already has measures in place to manage PSTVd. The  
Ministry for Primary Industries   RMP: Proposed Amendments to Seed for Sowing IHS  • 7 current phytosanitary measures in the seed IHS are insufficient to manage the risk of 
PSTVd.  Currently  Chrysanthemum  coronarium  must only comply with the b asic 
requirements, and Petunia must comply with the basic requirements and the specific 
requirements of Part 2.58 Petunia .  
 
(24) Due to the knowledge that PSTVd is seed -transmitted on Chrysanthemum  coronarium  
and Petunia , and because the pathways are open and active , MPI considers that there 
is a lack of measures in place to manage th e risk of introduction .  
 
(25) PSTVd is the type member of the family Pospiviroidae . It is known to have an 
extremely high mutation rate. It has a wide host range asymptomatically (including 
Chrysanthemum  coronarium  and Petunia ) and experimentally. Severe symptoms and 
large -scale outbreaks are mainly known to occur on Capsicum annuum , Solan um 
lycopersicum  and S. tuberosum ; all of which are important species for the New 
Zealand economy (see Table 1).  
 
Table 1: FreshFacts 2019 report summary ( Horticulture New Zealand, Plant & Food Research, 
2019)  
Species  Domestic (2018)  Exports (2019)  
Capsicum annuum  
(capsicum)  NZ$25 million NZ$20.6 million 
Solanum lycopersicum  
(tomato)  $184.5 million $14.5 million 
Solanum tuberosum   
(potato)  $139 million $129.4 million 
 
(26) PSTVd is on the New Zealand Priority Plant Pests and Diseases list  and is already 
managed on the  Seeds for Sowing  IHS under the special requirements for Capsicum , 
Solanum  and Solanum lycopersicum .. 
 
 
1.8 Information sources  
(27) The following information was used to assess the risk organisms related to the 
proposed changes, and the appropriate measures to manage their entry and 
establishment in New Zealand:  
• The MPI Emerging Risks biosecurity ri sk monitoring system  
• Technical advice in appendices 6.2, 6.3 and 6.4 of this RMP  
• Relevant literature and database searches  
• Technical information provided by the Netherlands ’ NPPO  
• Stakeholder discussions prior to, and during , the development of this RMP  
  8 • RMP: Proposed Amendments to Seed for Sowing IHS  Ministry for Primary Industries  2 Proposed changes to the Standard  
2.1 Proposed removal  of ELISA as a testing option for Tomato brown rugose fruit 
virus on Capsicum sp. and Solanum lycopersicum seeds for sowing  
(28) MPI propos es remov ing ELISA as a testing method for TBRFV  from the Part 2: 
Specific requirements for Capsicum  and Solanum lycopersicum  in the Standard.  
Remov ing ELISA as a testing option will mean that capsicum and tomato seed 
consignments imported into New Zealand will need  to be officially tested using an 
NPPO -approved PCR method (RT-PCR or RT -qPCR) and found free from TBRFV if 
they are not sourced from a ‘pest -free area’ or a ‘pest -free place of production’ free 
from TBRFV. The testing may be performed onshore or offshore o n a representative 
sample of a minimum of 3 ,000 seeds officially drawn according to the ISTA or AOSA 
sampling methodology.  
 
(29) The impact of the proposed changes to the Standard is illustrated in Appendix 6.1. 
 
 
2.2 Proposed requirements  for Hemp mosaic virus  and Hemp streak virus  on 
Cannabis sativa  
(30) MPI propos es the following changes to the Standard:  
• Remove “Hemp mosaic virus” and “Hemp streak virus” from the regulated pest 
list for Cannabis sativa  seed for sowing . 
• Remove the requirement for an additional declaration on phytosanitary certificates 
that Cannabis sativa  seed for sowing has been sourced from a ‘p est-free area’ free 
from “Hemp mosaic virus” and “Hemp streak virus” . 
• Remove the requirement for an additional declaration on phytosanitary certificates 
that Cannabis sativa  seed for sowing has been sourced from a ‘pest -free place of 
production’ free from “Hemp mosaic virus” and “Hemp streak virus” . 
 
(31) These proposed  changes apply to Cannabis sativa  seed for sowing imported from all 
countries.  
 
(32) The impact of the proposed changes to the Standard is illustrated in Appendix 6.1.  
 
 
2.3 Proposed requirements  for Artichoke yellow ringspot virus  on Phaseolus  
(33) MPI propos es the following changes to the Standard:  
• Remove Artichoke yellow ringspot virus  from the regulated pest list for Phaseolus  
seed for sowing . 
• Remove the requirement for an additional declaration on phytosanitary certificates 
that Phaseolus  seed for sowing has been sourced from a ‘pest -free area’ free from 
Artichoke yellow ringspot virus . 
• Remove the requirement for an additional declaration on ph ytosanitary certificates 
that Phaseolus  seed for sowing has been sourced from a ‘pest -free place of 
production ’ free from Artichoke yellow ringspot virus . 
  
Ministry for Primary Industries   RMP: Proposed Amendments to Seed for Sowing IHS  • 9 (34) These proposed  changes apply to seed for sowing imported from all approved 
countries currently listed in the Standard.  
 
(35) The impact of the proposed changes to the Standard is illustrated in Appendix 6.1. 
 
 
2.4 Proposed requirements  for Pea enation mosaic virus  on Pisum  and Vicia 
(36) MPI propos es the following changes to the Standard:  
• Remove Pea enation mosaic virus  from the regulated pest list s for Pisum  seed for 
sowing  and Vicia  seed for sowing . 
• Remove the requirement for an additional declaration on phytosanitary certificates 
that Pisum  seed for sowing has been sourced from a ‘pest -free area’ free from Pea 
enation mosaic virus . 
• Remove the requirement for an additional declaration on phytosanitary certificates 
that Pisum  seed for sowing has been sourced from a ‘pest -free place of production ’ 
free from Pea enation mosaic virus . 
• Remove the requirement for an additional declaration o n phytosanitary certificates 
that Vicia  seed for sowing has been sourced from a ‘pest -free area’ free from Pea 
enation mosaic virus . 
• Remove the requirement for an additional declaration on phytosanitary certificates 
that Vicia  seed for sowing has been sourced from a ‘pest -free place of production ’ 
free from Pea enation mosaic virus . 
 
(37) These proposed  changes apply to seed for sowing imported from all approved 
countries currently listed in the Standard.  
 
(38) The impact of the proposed  changes to the Standard is illustrated in Appendix 6.1. 
 
 
2.5 Proposed requirements  for Peanut stunt virus  on Phaseolus  and Vicia 
(39) MPI propos es the following changes to the Standard:  
• Remove Peanut stunt virus  from the regulated pest lists for Phaseolus  seed for 
sowing  and Vicia  seed for sowing . 
• Remove the requirement for an additional declaration on phytosanitary certificates 
that Phaseolus  seed for sowing has been sourced from a ‘pest -free area’ free from 
Peanut stunt virus . 
• Remove the requirement for an additional declaration on phytosanitary certificates 
that Phaseolus  seed for sowing has been sourced from a ‘pest -free place of 
production ’ free  from Peanut stunt virus . 
• Remove the requirement for an additional declaration on phytosanitary certificates 
that Vicia  seed for sowing has been sourced from a ‘pest -free area’ free from 
Peanut stunt virus . 
• Remove the requirement for an additional declaration on phytosanitary certificates 
that Vicia  seed for sowing has been sourced from a ‘pest -free place of production ’ 
free from Peanut stunt virus . 
 
(40) These proposed  changes apply to seed for sowing imported from all approved 
countries currently listed in the Standard.  10 • RMP: Proposed Amendments to Seed for Sowing IHS  Ministry for Primary Industries   
(41) The impact of the proposed changes to the Standard is illustrated in Appendix 6.1. 
 
 
2.6 Proposed requirements for Potato spindle tuber viroid on Chrysanthemum  
coronarium  and Petunia sp. 
(42) MPI propos es the following changes to the IHS: 
• Add a Glebionis  subpart in Part 2 specific requirements . 
• Add Glebionis coronaria  to the Plants Biosecurity Index with the seed for sowing 
import specification “see 155.02.05 under Glebionis ” and the nursery stock import 
specification “L2 see 155.02.06 under Chrysanthemum ”. 
• In the Plants Biosecurity index, change the  entry for Chrysanthemum coronarium 
to show that it is a synonym of Glebion is coronaria , thereby giving 
Chrysanthemum coronarium  a blank import specification and being subject to the 
import specification of the accepted name Glebionis coronaria .   
• Add PSTVd to the pest lists for Glebionis  and Petunia  sp. seed for sowing.  
• Add a requirement for Glebionis  and Petunia sp. seed for sowing for a 
phytosanitary certificate with the following options for additional declarations : 
i. Produced in a pest  free area free from Potato spindle tuber viroid . 
ii. Produced in a pest  free place of production where  parent  plants have been 
tested according to an NPPO  approved methodology and found free Potato 
spindle tuber viroid . 
iii. Officially tested, on a representative sample of a minimum of 3000 seeds 
officially drawn according to the ISTA or AOSA sampling methodology using 
an NPPO  approved PCR testing method , and found to be free from Potato 
spindle tuber viroid . 
 
(43) These proposed  changes apply to seed for sowing imported from all a pproved 
countries listed in the Standard.  
 
(44) The impact of the proposed changes to the Standard is illustrated in Appendix 6.1.  
There is also a proposed minor change to Part 2.58.2(1) for Petunia . This corrects the 
labelling of the subclauses to the letter “b” for option 2.  
   
Ministry for Primary Industries   RMP: Proposed Amendments to Seed for Sowing IHS  • 11 3 Rationale for the proposed change s to the Standard  
(45) The following section outline s information that provide s the reason for the proposed 
changes to measures  in the Standard . 
 
3.1 Removal of ELISA as a testing option for Tomato brown rugose fruit virus  on 
Capsicum  sp. and Solanum lycopersicum  seeds for sowing  
(46) ELISA is a less specific and less sensitive method than PCR for detection of TBRFV. 
The ELISA test for TBRFV has been found to  cross -react with other tomato viruses , 
and the commercially available ELISA kits are not species -specific (Dombrovsky & 
Smith, 2017; EPPO, 2020  c). Several specific molecular tests have been described for 
the detection and identification of TBRFV , and development of new RT-PCR primers 
and validation of existing tests is in progress (EPPO , 2020 c) .  
 
(47) In general, analytical sensitivity of ELISA is lower than PCR. The sensitivity of RT -
qPCR for detecti ng Cucumber green mottle mosaic virus  (CGMMV ), a cucurbit -
infecting virus in the same Tobamovirus  genus as TBRFV, was demonstrated to be 
10,000 times more sensitive than double -antibody sandwich E LISA  (Torre et al. , 
2019). Conventional RT -PCR methods were found to be 100 times more sensitive 
than ELISA . 
 
(48) The c urrent phytosanitary import regulations of a number of countries, including 
Australia, the E uropean Union  and Japan now require  seed health testing for TBRFV 
to be performed using PCR and do not allow  ELISA due to its lower sensitivity and 
specificity for detecting the virus compared to PCR.  
 
(49) Onshore seed testing for TBRFV is performed by RT -qPCR using primers from the 
International Seed Federation’s International Seed Health Initiative for Vegetable 
Crops ( ISHI -veg) Protocol: Detection of Inf ectious Tomato brown rugose fruit virus  
(TOBRFV) in Tomato  and Pepper Seed . Their test can detect  the virus at low titres in 
imported tomato and capsicum seeds. The sensitivity and specificity of the test to 
allow detection of low levels of the virus ensures that an appropriate level of 
protection for New Zealand is achieved that reduces the likelihoo d of introduction of 
TBRFV into New Zealand to a very low level. It is necessary that the diagnostic 
testing for TBRFV performed on all seed lots imported into New Zealand, whether 
they are tested onshore or offshore, is sensitive and specific enough to detect the 
presence of low levels of the virus. Removal of ELISA as a testing option in the 
Standard  will ensure that the level of protection achieved by offshore testing for 
TBRFV meets this requirement.  
 
(50) The option to test capsicum  and tomato  seeds for TBRFV using ELISA was 
introduced in the Standard  in March 2019 as an emergency measure to manage risk 
from TBRFV on the se import pathways . The strength of the measure  was calibrated 
on the level of perceived risk from TBR FV based on assessment of available scientific 
information about this pest  available  at the time. Since then , new information has 
become available about the biology and epidemiology of TBRFV as well as its rapidly 
expanding distribution to countries where it was previously not known to be present  
(Crop Protection Compendium datasheet, 2020). This indicates an increased 12 • RMP: Proposed Amendments to Seed for Sowing IHS  Ministry for Primary Industries  likelihood of entry of the virus into New Zealand , as tomato and capsicum seeds can 
be imported into New Zealand from all countries.  
 
(51) In December 2020, a joint MPI –GIA biosecurity response was undertaken  to contain 
and eradicate TBRFV that had entered New Zealand on an imported tomato seed lot 
that tested positive for the virus at a low titre. The decision to undertake the response 
was based on consideration that entry of even low levels  of virus in the seeds had 
potential to establish and spread to cause unwanted impacts to  New Zealand’s 
capsicum and tomato industries .  
 
(52) The likelihood of introduction of TBRFV to cause unwanted impacts for New 
Zealand’s capsicum and tomato industries is non -negligible if multiple imports of 
seeds contaminated with TBRFV at levels below the limits of detection of ELISA 
testing occur. While a lo w level of virus may not immediately establish an infection, 
due to the virus’ stability, there is potential for an environmental reservoir to build up, 
this could lead to future TBRFV outbreaks. V iral particles of tobamoviruses are 
extremely stable and in fectivity is preserved in seeds for up to several years 
(Dombrovsky & Smith, 2017). TBRFV can survive in contaminated soils, crop debris 
and on implements for years. Contaminated soils, irrigation water and nutrient 
solutions are also potential sources of the virus (Crop Protection Compendium 
datasheet, 2020).  
 
 
3.2 Non-viral nature of Hemp mosaic virus  and Hemp streak virus  on Cannabis 
sativa  
(53) The proposed changes reflect the conclusion by MPI that there is insufficient scientific 
evidence to support measures for “Hemp mosaic virus” (HMV) and “Hemp streak 
virus” (HSV) on Cannabis sativa  seed for sowing.  
 
(54) This conclusion is based on a recent assessment of available scientific information  
(MPI, 2 020). This assessment (see Appendix  0) found insufficient evidence to support 
the existence of “Hemp mosaic virus” and “Hemp streak virus” as causal agents for 
these similarly  named diseases.  
 
(55) The recent assessment by MPI was con sistent with an earlier technical advice about  
growing season inspection for detection of HMV and HSV on C. sativa  (MPI, 2018) . 
That assessment by MPI recommended removing HMV and HSV from the list of 
pests regulated by the Standard , unless further evidence was found that these are 
actual biotic entities causing unwanted impacts.  
 
(56) A further literature search using the terms “  ‘hemp mosaic’ OR ‘hemp streak’  ” and 
“cannabis” has now been conducted in CAB Abstracts and Google Scholar to check if 
there is any other causal agent that has been attributed to hemp mosaic or hemp streak 
disease since 2018.  
 
(57) No study has identified the causal agent of hemp mosaic or hemp streak disease since 
2018 . As such, seed transmission of these diseases cannot be determined, as no 
causative agent has been confirmed for the diseases.   
Ministry for Primary Industries   RMP: Proposed Amendments to Seed for Sowing IHS  • 13  
 
3.3 Host status of Phaseolus  for Artichoke yellow ringspot virus   
(58) The proposed changes reflect the conclusion by MPI that there is insufficient evidence 
to support measures for Artichoke yellow ring spot virus  (AYRSV ) on Phaseolus  seed 
for sowing.  
 
(59) This conclusion is based on an assessment of available scientific information (MPI, 
2020) . 
 
(60) Technical  assessment of evidence (see Appendix 0) found that natural host status 
could not be confirmed from the available evidence , although Phaseolus  spp. have 
been reported as experimental hosts of AYRSV in some studies (Avgelis et al. , 1992; 
Maliogka et al. , 2006; Paylan et al. , 2013; Rana et al. , 1980 ). 
 
(61) Literature searches using the terms “Artichoke yellow ring spot” and “Phaseolus” and 
“seed” did not provide evidence for seed transmission of AYRS V on Phaseolus  spp.. 
Hence, i n the absence of seed transmission , the virus is not a risk on the seed pathway.  
 
 
3.4 Seed transmission of Pea enation mosaic virus  on Pisum  and Vicia 
(62) The proposed changes reflect the conclusion  by MPI that there is insufficient evidence 
to support measures for Pea enation mosaic virus  (PEMV) on Pisum  seed for sowing 
and Vicia  seed for sowing . 
 
(63) This conclusion is based on  an assessment of available scientific information (MPI, 
2019).  
 
(64) The technical assessment by MPI (see Appendix 6.3) concluded:  
• There is insufficient evidence to confirm  that PEMV is seed -transmitted in 
Pisum  sp. or Vicia  sp., in agreement with the conclusion of the Netherlands’ 
NPPO.  
• There is evidence to suggest PEMV is seedborne in Pisum  sp. and may also be 
seedborne i n Vicia  sp. However, no evidence was found PEMV is seed -transmitted 
in any host.  
• Historical references cite that PEMV is seed -transmitted in Pisum  sp. However, 
this obs ervation has not been reproduced in recent literature.  
 
(65) Literature searches using Google, Google Scholar  and of CAB Abstract s did not 
provide evidence for seed transmission of PEMV in Pisum or Vicia  spp. 
 
 
3.5 Seed transmission of  Peanut stunt virus  on Phaseolus  and Vicia 
(66) The proposed changes reflect the conclusion by MPI that there is insufficient evidence 
to support measures for  Peanut stunt virus  (PSV) on Phaseolus  seed for sowing and 
Vicia  seed for sowing.  
 14 • RMP: Proposed Amendments to Seed for Sowing IHS  Ministry for Primary Industries  (67) This conclusion is based on  an assessment of available scientific information (MPI, 
2019) .  
 
(68) The technical assessment by MPI (see Appendix 6.3) concluded  there is insufficient 
evidence to confirm that Peanut stunt virus  is seed -transmitted on Phaseolus  sp. or 
Vicia  sp., in agreement with the conclusion of the Netherlands’ NPPO . 
 
(69) Literature searches using Google, Google Scholar  and CAB Abstracts did not provide 
evidence to contradict older reports that indicated PSV is not seed -transmitted in 
Phaseolus nor did they provide evidence that it is seed -transmitted in Vicia  spp. 
 
 
3.6 Rationale for the proposed requirements for Potato spindle tuber viroid on 
Chrysanthemum  coronarium  and Petunia sp. 
(70) There  is risk associated with PSTVd entering New Zealand by the Chrysanthemum  
coronarium and Petunia  seeds for sowing pathways, and specific requirements  are 
needed for the following reasons:  
 
• PSTVd has the potential to enter New Zealand on the Chrysanthemum  coronarium  
and Petunia  sp. seeds for sowing pathway.  
i) PSTVd is known to be seed -transmitted on both Chrysanthemum  coronarium  
and Petunia  sp. 
ii) PSTVd is globally widespread and is found in Africa, Asia, Australia, Central 
America, Europe and South America.  
iii) PSTVd is asymptomatic in both Chrysanthemum  coronarium  and Petunia  sp., 
meaning that interception of the viroid without testing requirements is highly 
unlikely.  
iv) The Chrysanthemum coronarium  and Petunia  sp. seeds for sowing pathways 
are open  and active . 
 
• If entry occurred, spread and establishment of PSTVd is highly likely within New 
Zealand.  
i) PSTVd is  not limited to insect vector transmission and is easily spread through 
mechanical transmission, pollen, distribution of seed and physical contact 
between healthy and diseased plants. This gives PSTVd  the potential  to infect 
symptomatic hosts of economic importance.  
ii) Asymptomatic host plants have the potential to serve as a reservoir for the 
disease . 
iii) Historic detections of PSTVd in New Zealand  and PSTVd’s  wide global 
distribution  suggest that climate will not be a limiting factor.  
 
• If establishment and spread occur s, the likelihood of impact is high.  
i) Spread from asymptomatic hosts to symptomatic hosts has potential to cause 
undesirable economic impacts.  
ii) Severe symptoms and large -scale outbreaks of PSTVd are mainly known to 
occur on Capsicum annuum , Solanum lycopersicum  and S. tuberosum  with 
decreases in yield corresponding to increases in infection.   
Ministry for Primary Industries   RMP: Proposed Amendments to Seed for Sowing IHS  • 15 iii) Losses of yield in Capsicum annuum , Solanum lycopersicum  and S. tuberosum  
could res ult in significant impact to their million -dollar industries (see table 1).  
 
(71) It is worth noting that  a concern that some may have is that the proposed changes 
concern  managing a pest on seeds of a plant species , where th ose plant species 
themselves would be unlikely to be impacted.  However, due to PSTVd being a high 
risk to the Capsicum annuum , Solanum lycopersicum  and S. tuberosum  industries, 
being managed on th ose pathways , and being easily spread between host species, 
management is necessary  on Chrysanthemum coronarium and Petunia seeds for 
sowing.  
 
(72) The measures for PSTVd are being proposed at a genus level for Petunia sp. as the 
evidence for seed transmission comes from a species within the genus Petunia  
(Petunia x hybrida ). The level of reported seed transmission is also very high (81%), 
so the risk of other species within the genus having unreported seed transmission is of  
concern and measures are considered necessary for the entire genus.  
 
(73) The measures for PSTVd are being proposed for the accepted name Glebionis 
coronaria  and synonym Chrysanthemum coronarium  because  these are the only 
members of the genus Glebionis currently eligible for import.  The evidence for seed 
transmission comes from a report on the accepted name Glebionis coronaria , with a 
1.2% rate  of seed transmission . Therefore, the h igh volumes of imported 
Chrysanthemum  coronarium  seed combined with the potential for PSTVd to build up 
an asymptomatic reservoir means  even a low level of seed transmission is a concern 
for imports of this species.  
 
(74) MPI propose s requir ing pest-free places of production to be established and 
maintained based on parent plant testing according to an NPPO -approved 
methodology. This requirement aligns with the requirements for PSTVd on the 
Chrysanthemum sp. and Petunia sp. nursery stock pathways. The need for parent plant 
testing  is a result of PSTVd being asymptomatic on these hosts, and growing season 
inspection being insufficient for detecting infection  and establishing a pest -free place 
of production .  
 
  16 • RMP: Proposed Amendments to Seed for Sowing IHS  Ministry for Primary Industries  4 Feasibility of the proposed change s to the Standard  
 
4.1 Proposed removal  of ELISA  as a testing option for Tomato brown rugose fruit 
virus  on Capsicum  sp. and Solanum lycopersicum seeds for sowing  
(75) The proposed removal of ELISA as a testing option, thereby requiring ‘official 
testing’ of all capsicum and tomato seeds for sowing imported into New Zealand to be 
performed using an NPPO -approved PCR method , is feasible , as laid out below.  
 
(76) Several specific molecular tests are now described for identif ying TBRFV and are 
available for exporting NPPOs to use for testing capsi cum and tomato seed lots to be 
exported to New Zealand if testing is done offshore  (EPPO, 2020  c).  
 
(77) The Standard  does also offer the option for capsicum and tomato seeds to be tested for 
TBRFV onshore. MPI ’s Plant Health & Environment Laboratory  is able to test 
imported capsicum and tomato seeds onshore for TBRFV using RT-qPCR . The 
indicative cost of RT -qPCR testing of a sample of 3 ,000 untreated seeds  for TBRFV is 
NZ$1,020 (excl. GST). In the case of a positive RT-qPCR test , an additional 
sequencing charge of $100 to confirm virus identity would apply , bringing the cost to 
$1,120. On the other hand, the indicative cost of an ELISA assay is $650 (ex cl. GST). 
However, in the event of a positive ELISA result, confirmation of virus identity will 
require nucleic acid extraction, PCR and sequencing at an additional cost of $295 
(excl. GST) , bring the total cost to $945 (excl. GST) . This is because the ELISA assay 
is generic for tobamovi ruses , and molecular testing and sequencing would be required 
to confirm a TBRFV detection.  
 
(78) Work on development  and validation of RT-PCR tests is ongoing, which is expected 
to widen exporting NPPOs’ access and ability to undertake RT-PCR testing for 
TBRFV on seeds exported to New Zealand in future. This includes work on an EPPO 
diagnostic protocol for TBRFV covering diagnosis of TBRFV on seed. An Euphresco  
project  and activities within the H2020 Valitest Project (https://www.valitest.eu/) were  
also underway in 2020 to validate a number of RT-PCR and real -time RT-PCR tests 
for the detection and identification of TBRFV on seed. (EPPO, 2020  c). 
 
(79) It is acknowledg ed that there may be shipments of capsicum and tomato seeds for 
sowing currently en  route to New Zealand accompanied by phytosanitary certificates 
that certify official testing of the seeds for TBRFV using ELISA. To ease the 
compliance costs for these impo rters, a one-month implementation period is proposed 
before  the new IHS measure comes into force.  
 
(80) Requiring on -arrival PCR testing for TBRFV for these consignments instead of a one-
month implementation period is not proposed , due to the additional testing costs that 
this would pose to importers. Furthermore, onshore RT-PCR testing will require 
testing a 3 ,000 seed sample from the consignment. This could potentially lead to 
destruction of a considerable proportion  of the consig nment , especially if small seed  
lots are being imported , incurring losses to the importer. Recogni sing that ELISA 
testing does provide a level of protection against TBRFV, a one-month 
implementation period is considered justified . This will allow importers  to make the 
necessary arrangements with their overseas suppliers to ensure that the seeds are tested  
Ministry for Primary Industries   RMP: Proposed Amendments to Seed for Sowing IHS  • 17 offshore for TBRFV using an NPPO -approved  PCR or alternatively  are shipped to 
New Zealand to be tested onshore.  
 
 
4.2 Proposed removal  of measures for Hemp mosaic virus and Hemp streak virus 
on Cannabis sativa  seed for sowing  
(81) The proposed changes will align the requirements of the Standard with those requested 
by an exporting country. Those proposed changes  would  remove an existing 
requireme nt for an additional declaration to the phytosanitary certificate required by 
the Standard for imported seed consignments (see Appendix 6.3 for proposed changes 
to applied to the current IHS).  
 
(82) The proposed changes apply to the requirements for Cannabis s ativa seed for sowing  
only and do not affect measures required by the Standard for any other commodity.  
 
(83) The proposed changes would  not involve imposing new requirements for imported 
seed and do not affect other requirements of the Standard.  
 
(84) The proposed changes will facilitate trade by removing a potential barrier to an 
offshore NPPO issuing a phytosanitary certificate for import ation of Cannabis sativa  
seed for sowing  into New Zealand . 
 
(85) The proposed changes will not impose additional costs on Ne w Zealand importers.  
 
 
4.3 Proposed removal  of measures for Artichoke yellow ringspot virus  on 
Phaseolus   
(86) The proposed changes will align the requirements of the Standard with those requested 
by an exporting country. Those proposed changes would  remove an existing 
requirement for an additional declaration to the phytosanitary certificate required by 
the Standard for imported seed consignments (see Appendix 6.3 for proposed changes 
to applied to the current IHS).  
 
(87) The proposed changes apply to the requirements for Phaseolus only and do not affect 
measures required by the Standard for other commodit ies3. 
 
(88) The proposed changes would  not involve imposing new requirements for imported 
seed and do not affect other requirements of the Standard.  
 
(89) The proposed changes will facilitate trade by removing a potential barrier to an 
offshore NPPO issuing a phytosanitary certificate for import ation of Phaseolus seed 
for sowing  into New Zealand . 
 
(90) The proposed changes will not impose additional costs on New Zealand importers.  
 
 
 
3 The current Standard requires measures to manage risk from Artichoke yellow ringspot virus  on Vicia  seed for sowing.  18 • RMP: Proposed Amendments to Seed for Sowing IHS  Ministry for Primary Industries  4.4 Proposed removal  of measures for Pea enation mosaic virus  on Pisum  and 
Vicia 
(91) The proposed changes will align the requirements of the Standard with th e 
requirements  requested by an exporting country. Those proposed  changes would  
remove an existing requirement for an additional declaration to the phytosanitary 
certificate required by  the Standard for imported seed consignments (see Appendix 6.3 
for proposed changes to applied to the current IHS).  
 
(92) The current Standard requires measures to manage risk from Pea enation mosaic virus  
only for Pisum  and Vicia . 
 
(93) The proposed changes do not affect measures required by the Standard for other 
commodities.  
 
(94) The proposed changes would  not involve imposing new requirements for imported 
seed and do not affect other requirements of the Standard.  
 
(95) The proposed changes will facilitate trade by rem oving a potential barrier to an 
offshore NPPO issuing a phytosanitary certificate for import ation  of Pisum seed for 
sowing  into New Zealand . 
 
(96) The proposed changes will not impose additional costs on New Zealand importers.  
 
 
4.5 Proposed removal  of measures for Peanut stunt virus  on Phaseolus  and Vicia 
(97) The proposed changes will align the requirements of the Standard with those requested 
by an exporting country. Those proposed changes would  remove an existing 
requirement for an additional declaration to the phytosanitary certificate required by 
the Standard for imported seed consignments (see Appendix 6.3 for proposed changes 
to applied to the current IHS).  
 
(98) The proposed changes apply to th e requirements for Phaseolus and Vicia  only and do 
not affect measures required by the Standard for other commodities4. 
 
(99) The proposed changes would  not involve imposing new requirements for imported 
seed and do not affect other requirements of the Standard.  
 
(100)  The proposed changes will facilitate trade by removing a potential barrier to an 
offshore NPPO issuing a phytosanitary certificate for import ation of Phaseolus and 
Vicia seed for sowing  into New Zealand . 
 
(101)  The proposed changes will not impose additional costs on New Zealand importers.  
 
 
 
4 The current Standard requires measures to manage risk fr om Peanut stunt virus  on Medicago  seed for sowing and Pisum  
seed for sowing .  
Ministry for Primary Industries   RMP: Proposed Amendments to Seed for Sowing IHS  • 19 4.6 Feasibility of the proposed requirements for Potato spindle tuber viroid on 
Chrysanthemum  coronarium  and Petunia sp. 
(102)  MPI propose s addin g specific requirements for Chrysanthemum coronarium  seeds,  
which currently only have to meet the  basic conditions of the IHS . This means when 
importing Chrysanthemum coronarium  seeds, a phytosanitary certificate will now be 
required  which will incur an additional cost to importers . 
 
(103)  MPI propose s requiring  another additional declaration on phytosanitary certificates for 
Petunia sp. seeds,  which already require a phytosanitary certificate. The re will be an  
additional cost for importers if testing is the option used to declar e the consignment 
free from PSTVd.  
 
(104)  The proposed requirements  are feasible , as they align with the established measure s 
for PSTVd set out in the specific requirements for Capsicum , Solanum , and Solanum 
lycopersicum . While it is recognised that the proposed measures will incur an extra 
cost to importers, they will manage the risk of PSTVd on Chrysanthemum coronarium  
and Petunia sp. to an appropriate level of protection. Measures are  deemed necessary 
to prevent the establishment in New Zealand of the high -priority pest PSTVd  and the 
subsequent loss of yield  to economically important symptomatic host species . 
 
  20 • RMP: Proposed Amendments to Seed for Sowing IHS  Ministry for Primary Industries  5 References  
• Avgelis, A D; Katis, N; Grammatikaki, G (1992) Broad bean wrinkly seed caused by 
artichoke yellow ringspot nepovirus. Annals of  Appl ied Biology, 121: 133 –142.  
• Crop Protection Compendium (2020)  Tomato brown rugose fruit virus datasheet: 
https://www.cabi.org/cpc/datasheet/88757522  (Accessed 19/02/2020)  
• Davino , S; Giovanni -Caruso , A; Bertacca , S; Barone , S; Panno , S (2020) Tomato 
brown rugose fruit virus : Seed transmission rate and efficacy of different seed 
disinfection treatments. Plants , 9(11): 1615.  
• Dombrovsky A ; Smith E (2017) Seed transmission  of tobamoviruses: aspects  of 
global disease distribution . In Adva nces in Seed Biology  (INTECH, Vol. Chapter 12, 
pp. 233 –260).  
• EPPO (2020  a) Tomato brown rugose fruit virus  datasheet. Tomato brown rugose fruit 
virus (TOBRFV)[Datasheet]| EPPO Global Database  (Accessed 19/02/2020)  
• EPPO (2020  b) Tomato brown rugose fruit virus  – A threat to tomato and pepper . 
EPPO_poster_ToBRFV.pptx (live.com)  (Accessed 19/02/2020)   
• EPPO (2020 c) Pest Risk Analysis for Tomato brown rugose fruit virus   
https://pra.eppo.int/pra/e1e025c7 -a704 -46b8 -90da -b26015bc6068  (Accessed 
19/02/2020)  
• Horticulture New Zealand, Plant & Food Research (2019). Fresh Facts 2019 edition, 
https://www.freshfacts.co.nz/files/freshfacts -2019.pdf  
• IPPC (2020) International Standard for Phytosanitary Measures 38: International 
movement of seeds. 
https://www.ippc.int/static/media/files/publication/en/2017/05/ISPM_38_2017_En_20
17-05-15.pdf  
• Maliogka, V I; Dovas, C I; Lesemann D E; Winter, S; Katis, N I (2006) Molecular 
identification, r everse transcription -polymerase chain reaction detection, host 
reactions , and specific cytopathology  of Artichoke yellow ringspot virus  infecting 
onion crops . Phytopathology , 96: 622 –629. 
• MPI (2009 ) Balance in Trade. Ministry for Primary Industries, Wellington. [online 
reference. ISBN 978 -0-478-33881 -2] 
• MPI (2019 ) Technical advice (17 Dec 2019 ), Plant Import Risk Assessment. Ministry 
for Primary Industries, Wellington.  
• MPI (2020 ) Technical advice (21 April 2020 ), Plant Import Risk Assessment . 
Ministry for Primary Industries, Wellington.  
• MPI (2020a) Scientific and technical advice on whether measures are required to 
manage the risk from Potato spindle tuber viroid  (PSTVd) on seed for sowing of the 
ornamental species Dahlia , Chrysanthemum  and Diascia , eligible to import under IHS 
155.02.05: Seeds for Sowing.  
• Official New Zealand Pest Register (2020) 
https://pierpestregister.mpi.govt.nz/PestsRegister/ImportCommodity/  (Accessed 
10/02/2021)  
• Paylan, C; Ergun, M; Erkan, S (2013) First report  of Artichoke yellow ringspot virus  
in globe artichoke  in Turkey. Plant Disease , 97(10): 1,388.1 –1,388.1. 
http://dx.doi.org/10.1094/PDIS -04-13-0423 -PDN  
• Torre , C; Agüero, J; Gómez-Aix, C; Aranda , M A (2019) Comparison of DAS -ELISA 
and qRT -PCR for the detection of cucurbit viruses in seeds. Annals of Applied Biology , 
176(2): 158–169. https://doi.org/10.1111/aab.12543   
Ministry for Primary Industries   RMP: Proposed Amendments to Seed for Sowing IHS  • 21 • Rana, G  L; Gallitelli, D; Kyriakopoulou, P  E; Russo, M; Martelli, G P (1980) Host 
range and properties of artichoke yellow ringspot virus. Annals of  Appl ied Biology, 
96(2): 177 –185.  
  22 • RMP: Proposed Amendments to Seed for Sowing IHS  Ministry for Primary Industries  6 Appendices  
6.1 Illustration of p roposed changes applied to the Standard  
Proposed changes applied to requirements for Cannabis sativa  seed for sowing  
 
  
 
Ministry for Primary Industries   RMP: Proposed Amendments to Seed for Sowing IHS  • 23  
24 • RMP: Proposed Amendments to Seed for Sowing IHS  Ministry for Primary Industries    
 
Ministry for Primary Industries   RMP: Proposed Amendments to Seed for Sowing IHS  • 25 Proposed changes applied to requirements for Caps icum seed s for sowing  
 
 
 
 
 
 
 
26 • RMP: Proposed Amendments to Seed for Sowing IHS  Ministry for Primary Industries   
 
 
 
Ministry for Primary Industries   RMP: Proposed Amendments to Seed for Sowing IHS  • 27   
28 • RMP: Proposed Amendments to Seed for Sowing IHS  Ministry for Primary Industries  Proposed new schedule for Glebionis  (including Chrysanthemum coronarium ) seed for sowing  
 
 
Ministry for Primary Industries   RMP: Proposed Amendments to Seed for Sowing IHS  • 29 Proposed changes applied to requirements for Petunia  seed for sowing  
 
30 • RMP: Proposed Amendments to Seed for Sowing IHS  Ministry for Primary Industries   
 
Ministry for Primary Industries   RMP: Proposed Amendments to Seed for Sowing IHS  • 31 Proposed changes applied to requirements for Phas eolus seed for sowing  
 
32 • RMP: Proposed Amendments to Seed for Sowing IHS  Ministry for Primary Industries   
 
 
Ministry for Primary Industries   RMP: Proposed Amendments to Seed for Sowing IHS  • 33  
 
 
34 • RMP: Proposed Amendments to Seed for Sowing IHS  Ministry for Primary Industries   
 
 
 
 
Ministry for Primary Industries   RMP: Proposed Amendments to Seed for Sowing IHS  • 35 Proposed changes applied to requirements for Pisum  seed for sowing  
 
 
36 • RMP: Proposed Amendments to Seed for Sowing IHS  Ministry for Primary Industries   
 
 
Ministry for Primary Industries   RMP: Proposed Amendments to Seed for Sowing IHS  • 37  
 
38 • RMP: Proposed Amendments to Seed for Sowing IHS  Ministry for Primary Industries  Proposed changes applied to requirements for Solanum lycopersicum  seed for sowing  
 
 
 
 
 
 
 
Ministry for Primary Industries   RMP: Proposed Amendments to Seed for Sowing IHS  • 39  
 
 
 
 
 
 
40 • RMP: Proposed Amendments to Seed for Sowing IHS  Ministry for Primary Industries   
 
Ministry for Primary Industries   RMP: Proposed Amendments to Seed for Sowing IHS  • 41 Proposed changes applied to requirements for Vicia  seed for sowing  
 
42 • RMP: Proposed Amendments to Seed for Sowing IHS  Ministry for Primary Industries    
 
Ministry for Primary Industries   RMP: Proposed Amendments to Seed for Sowing IHS  • 43 6.2 Technical advice on whether Phaseolus  spp. is a natural host of Artichoke 
yellow ringspot virus  (AYRS V), and seed transmission of Hemp mosaic virus 
and Hemp streak virus on Cannabis sativa  
Background  
With the adoption of ISPM 38 (IPPC 2017) on international movement of seed, the NPPO -NL 
has started with the analysis of import requirements for seeds on its merits. The focus of the 
analysis is on whether or not organisms are seed -transmissible. For those organisms which 
the NPPO -NL concludes are not seed -borne or seed -transmitted, or that the plant species is 
not a host, the NPPO -NL will request the rationale for having such organisms regulated fro m 
the counterpart NPPO, and if possible, to have these organisms removed from the import 
requirement for seeds.  
  
Definitions of seed -borne pest and seed -transmitted pest (IPPC 2017):  
• Seed -borne pest: A pest carried by seeds externally or internally that may or may 
not be transmitted to plants growing from these seeds and cause their infestation.  
• Seed -transmitted pest: A seed -borne pest that is transmitted via seeds directly to 
plants growing from these seeds and causes their infestation.  
Summary of advi ce  
• This advice agrees with the NPPO -NL conclusion that there is insufficient 
evidence suggesting that Phaseolus  spp. are natural hosts of AYRS V. Also, there 
is no evidence showing that AYRS V is seed -transmissible on Phaseolus  spp.  
• This advice agrees with  the statement made by the NPPO -NL that the virial nature 
of hemp mosaic disease and hemp streak disease is unknown, and there is no 
such virus as HMV or HSV. Given that:  
o A previous advice on hemp mosaic and hemp streak disease provided by MPI 
and drafted  in 2018, provides supporting evidence for the statement made by 
the NPPO -NL.  
o No study has identified the causal agent of the hemp mosaic disease and 
hemp streak disease since 2018.  
Supporting information  
1. Is a Phaseolus  spp. a natural host of Articho ke yellow ringspot virus  (AYRSV)?  
The NPPO -NL concludes that Phaseolus  sp. is not a natural host of AYRS V. The following 
information is collected by MPI. It is concluded that Phaseolus  sp. is an experimental host of 
AYRS V, but there is insufficient evidence indicating Phaseolus  sp. is a natural host of 
AYRS V. The experimental conditions for infection of Phaseolus  are not likely to be replicated 
in field situations. Namely, the informati on MPI has found supports the conclusion made by 
the NPPO -NL.  
 
A literature search has been conducted in CAB Abstract and Google Scholar using terms 
“Artichoke yellow ring spot” and “Phaseolus”. Phaseolus  spp. have been reported as 
experimental hosts of A YRSV in some studies (Avgelis et al. 1992; Maliogka et al. 2006; 
Paylan et al. 2013). Systemic mosaic, reddish necrotic, local lesions, and malformation 
symptoms were observed when P. vulgaris  was mechanically inoculated with sap from globe 
artichoke ( Cyna ra cardunculus  L. subsp. scolymus  (L.) Hayek) that were infected by AYRSV.  
Phaseolus aureus  has also been reported to be infected by AYRS V after artificial inoculation, 
and symptoms include necrotic local lesions, and vein clearing (Rana et al. 1980).  
 
Two online databases (Descriptions of Plant Viruses – Rana et al. 1983; Plant Viruses Online 
– Brunt et al. 1996) indicate that P. vulgaris  is a natural host of AYRS V, however, source 44 • RMP: Proposed Amendments to Seed for Sowing IHS  Ministry for Primary Industries  publications could not be found. Rana et al. (1983) claim that, in nature,  the virus was found 
infecting 32 different plant species including French bean ( P. vulgaris ). However, the natural 
host information of AYRS V from this database cited unpublished information from P E 
Kyriakopoulou, and the source of this unpublished inform ation could not been found. 
Symptoms on P. vulgaris  are described in Brunt et al. (1996) under the “Natural host range 
and symptoms” section, but there is no reference cited for its natural host status. As such, 
this is an unconfirmed record.  
 
Another lit erature search was conducted in CAB Abstract and Google Scholar using terms 
“Artichoke yellow ring spot” and “Phaseolus” and “seed”, and no evidence for seed 
transmission of AYRS V on Phaseolus  spp. was found.  
 
2. Seed transmission of Hemp mosaic virus (HMV) and Hemp streak virus (HSV) on 
Cannabis sativa  
The NPPO -NL suggests removing HMV and HSV from the import requirement for Cannabis 
seeds, and concludes that: 1) the virial nature of hemp mosaic disease and hemp streak 
disease is unknown; 2) there is no such virus as hemp mosaic virus and hemp streak virus 
(ICTV, 2020). A recent technical advice provided by MPI, which was drafted in 2018, and any 
new information collected and examined by MPI, supports the conclusi on made by the 
NPPO -NL. A summary of the previous MPI technical advice and the new information 
collected is present ed in the following paragraphs.  
 
The previous technical advice on growing season inspection for detection of HMV and HSV 
on C. sativa  recomm ended removing HMV and HSV from the list of pests of concern in the 
IHS unless further evidence is found that these are actual biotic entities causing unwanted 
impacts. However, the advice suggests that the diseases of unknown aetiology referred to as 
hemp  streak and hemp mosaic disease should still be considered a biosecurity concern to 
New Zealand and be included in the IHS.  
 
As the above technical advice was drafted in 2018, a literature search using terms “’hemp 
mosaic’ or ‘hemp streak’” and “cannabis”  was conducted in CAB Abstracts and Google 
Scholar to check if there is any other causal agent that has been attributed to hemp mosaic 
or hemp streak disease since 2018. No study has identified the causal agent of hemp mosaic 
or hemp streak disease since 2 018. As such, seed transmission of these diseases cannot be 
determined, as no causative agent has been confirmed for the diseases.  
References  
• Avgelis, A D; Katis, N; Grammatikaki, G (1992) Broad bean wrinkly seed caused 
by artichoke yellow ringspot nepovi rus. Ann. Appl. Biol., 121: 133 – 142.  
• Brunt, A; Crabtree, K; Dallwitz, M; Gibbs, A; Watson, L; Zurcher, E (1996) Plant 
viruses online and lists from the VIDE. Available at: http://bio -
mirror.im.ac.cn/mirrors/pvo/vide/descr044.htm#Range    
• CPC (2020) Crop Protection Compendium. Available at: https://www.cabi.org/cpc , 
accessed on 30/04/2020. EPPO (2020) EPPO Global Database. Available at: 
https://gd.eppo.int/taxon/CORBSE , accessed on 30/04/2020.  
• ICTV (2020) International Committee on Taxonomy of Viruses. Available at: 
https://talk.ict vonline.org/taxonomy/    
• IPPC (2020) International Standard for Phytosanitary Measures 38: International 
movement of seeds. Available at: 
https://w ww.ippc.int/static/media/files/publication/en/2017/05/ISPM_38_2017_En_2017 -
05-15.pdf    
• Maliogka, V I; Dovas, C I; Lesemann D E; Winter, S; Katis, N I (2006) Molecular 
Identification, Reverse Transcription -Polymerase Chain Reaction Detection, Host  
Ministry for Primary Industries   RMP: Proposed Amendments to Seed for Sowing IHS  • 45 Reactions , and Specific Cytopathology of Artichoke yellow ringspot virus  Infecting 
Onion Crops. Phytopathology, 96: 622 -629.  
• Paylan, C; Ergun, M; Erkan, S (2013) First Report of Artichoke yellow ringspot 
virus  in Globe Artichoke in Turkey. Plant Disease, 97(10): 1 ,388.1 – 1,388.1. 
Available at: http://dx.doi.org/10.1094/PDIS -04-13-0423 -PDN   
• Rana, G; Gallitelli, D; Kyriakopoulou, P; Russo, M; Martelli, G (1980) Host range 
and properties of artichoke yellow ringspot virus. Ann. Appl. Biol., 96: 177 – 185.  
• Rana, G; Kyriakopoulou, P; Martelli, G (1983) Artichoke yellow ringspot virus . 
Descriptio ns pf plant viruses. Available at: 
http://www.dpvweb.net/dpv/showdpv.php?dpvno=271    
  46 • RMP: Proposed Amendments to Seed for Sowing IHS  Ministry for Primary Industries  6.3 MPI technical assessment: seed transmission of Pea enation mosaic virus  
(PEMV) on Pisum  sp. and Vicia sp. and Peanut stunt virus (PSV) on 
Phaseolus  sp. and Vicia sp. 
Background  
With the adoption of ISPM 38 on the international movement of seeds for sowing, the NPPO 
of the Netherlands has begun reviewing the import requirements placed on seeds they 
export.  The focus of their review is whether or not there is sufficient evidence for the 
organisms requiring import measures being seed -transmissible. For organisms that the 
NPPO of the Netherlands concludes are not seed -borne or seed -transmitted, they will 
reque st the rationale from the counterpart NPPO as to why the organism is regulated. 
Furthermore, if possible, to have the organism removed from the import requirements for 
seeds.  
Summary of advice  
• This advice agrees with the conclusion by the Netherlands’ NP PO that there is 
insufficient evidence to suggest that Pea enation mosaic virus  (PEMV) is seed -
transmitted in Pisum  sp. or Vicia  sp.  
• There is evidence to suggest that PEMV is seed -borne in Pisum  sp. and may also 
be on Vicia  sp. However, no evidence was found that PEMV is seed -transmitted 
in any host.  
• Historical references cite that PEMV is seed -transmitted in Pisum  sp. However, 
this observation has not been reproduced in recent literature.  
• This advice agrees with the concl usion by the Netherlands’ NPPO that there is 
insufficient evidence to suggest that Peanut stunt virus  (PSV) is seed -transmitted 
on Phaseolus  sp. or Vicia  sp.  
• Peanut stunt virus  (PSV)  has been reported to be seed -transmitted at low rates on 
Arachis hypogae a (peanut) and Glycine max  (soybean) seeds.  
Supporting information  
Seed transmission of Pea enation mosaic virus  on Pisum  sp. and Vicia  sp.  
The Dutch NPPO conclude that seed transmission of Pea enation mosaic virus  in Pisum  sp. 
is unlikely. They also co nclude that the virus is not seed transmitted in Vicia  sp. The 
information outlined below was collected by MPI for this advice. It is concluded that the 
evidence found supports the conclusions made by the Dutch NPPO that there is insufficient 
evidence that  PEMV is seed transmitted in Pisum  sp. or Vicia  sp. However, there is evidence 
to suggest that PEMV is seed -borne in Pisum  sp. and may also be on Vicia  sp.  
 
Pea enation mosaic disease is caused by two obligatory symbiotic viral genomes, PEMV -1, a 
member o f the Enamovirus  genus (family Luteoviridae ) and PEMV -2, in the Umbravirus  
genus (Demler et al, 1993; ICTV, 2019). There are no known examples of Enamoviruses or 
Umbraviruses being seed - transmitted (ICTV, 2019).  
 
Infection of many cultivars of Pisum  sp. with PEMV results in morphological changes. Small 
growths originating from  the underside of the leaves (enations) can develop. Seed pods may 
appear bumpy, twisted and deformed. On plants that are infected before flower bloom, the 
pods do not develop or fill normally (Kraft and Pfleger, 2001). This would reduce the risk of 
infect ed seeds being produced. However, plants may appear normal if infected after the 
flower bloom stage. The virus is transmitted in a persistent manner by eight species of 
aphids, with Acyrthosiphon  pisum  (pea aphid) being the most significant (Kraft and Pfle ger, 
2001). Acyrthosiphon  pisum  is present in New Zealand (NZOR, 2019). Kraft and Pfleger 
(2001) do not make any reference to the virus being seed transmitted.   
Ministry for Primary Industries   RMP: Proposed Amendments to Seed for Sowing IHS  • 47  
Seed transmission of PEMV in Pisum  sativum  was reported by Kovachevsky (1978) (cited in 
Timmer man-Vaughan et al, 2009 and Sastry, 2013). They reported the early -season 
development of PEMV disease in seedlings grown in the field from seeds collected from 
infected plants. They concluded that the spread of PEMV was due to seed transmission of 
the viru s, rather than de novo infection (Kovachevsky (1978); cited in Timmerman -Vaughan 
et al, 2009). The Kovachevsky paper was not able to be checked in full, as an English 
version could not be found. However, Timmerman -Vaughan et al (2009) state that the 
experi ment described in Kovachevsky (1978) is described as being conducted in the field 
and does not mention that measures were put in place to prevent aphid vectors becoming 
associated with the plants. Therefore, the PEMV symptoms may have been due to 
transmiss ion of the virus to the plants via aphids. Furthermore, no work has been found that 
substantiated the results mentioned by Kovachevsky (1978).  
 
The description of PEMV by Skaaf and de Zoeten (2000) states that PEMV is seed 
transmitted at low levels (1.5%) , citing Kovachevsky (1978). However, the original paper did 
not quantify the frequency of seed transmission (Timmerman -Vaughan et al, 2009). 
Therefore, this is considered incorrect. Sastry (2013) cite Blattry (1956), Kovachevsky 
(1978), Kheder and Eppler (1988) as reporting seed transmission of PEMV in Pisum  sativum . 
However, no details were given and the papers were not able to be checked as they were 
not published in English. Given that there has been no corroboration of the results described 
by Kovachev sky (1978) and a viable alternative explanation for the results has been put 
forward by Timmerman -Vaughan et al, 2009 this paper is not considered strong, reliable 
evidence that PEMV is seed -transmitted.  
 
Timmerman -Vaughan et al, (2009) investigated the a ccumulation of PEMV in P. sativum 
seeds and seed transmission of the virus in this host. The conclusion of the study was that 
the virus can be seed -borne, but there was no evidence of seed transmission. It was found 
that PEMV -1 and PEMV -2 genomic RNA accum ulated to high levels in all pod and seed coat 
samples tested. The genomes of PEMV -1 and PEMV -2 were also detected in some seed 
embryo tissue samples, but at much lower levels. Seeds collected from P. sativum  (variety 
Medora) plants infected with PEMV was used in one set of seed transmission experiments. 
Approximately 5000 seeds were grown out in an aphid free environment. No symptoms of 
PEMV disease were observed in any plants. A further 3000 of the seeds from the diseased 
Medora plants were grown under fi eld conditions and inspected for PEMV disease. Again, no 
symptoms of PEMV were observed. In another seed transmission test, 286 seedlings were 
grown from seeds collected from PEMV infected P. sativum  (variety Joel) pods. The plants 
didn’t show any symptoms  of PEMV disease at 27 days post germination and PEMV was not 
detected in the plants by ELISA testing.  
 
The evidence of Timmerman -Vaughan et al, (2009) suggests that it is unlikely that PEMV is 
seed transmitted in Pisum  sp. However, their data does sugges t that the virus is seed -borne. 
As mentioned in the paper ‘The possibility that altering factors such as plant genotype, virus 
strain, presence of other viruses, or environmental factors would result in PEMV seed 
transmissibility cannot be completely ruled  out because these possibilities have not been 
tested exhaustively’. Therefore, if new evidence was to become available, it may warrant the 
risk associated with PEMV to be reassessed.  
 
No evidence for seed transmission of PEMV was found using Google or Google Scholar, 
using the search terms ‘seed transmission pea enation mosaic virus Pisum ’, ‘seed 
transmission pea enation mosaic virus Vicia’  or ‘seed transmission pea enation virus’. The 
description by Skaaf and de Zoeten (2000) was found, however as mentioned above this 
information is not considered to be correct. A CAB Abstract using the search term ‘seed 48 • RMP: Proposed Amendments to Seed for Sowing IHS  Ministry for Primary Industries  transmission pea enation mosaic virus’ did not produce any results. There are no al erts 
relating to PEMV in the emerging risks system.  
 
Seed transmission of Peanut stunt virus (PSV) on Phaseolus  sp. and Vicia  sp.  
The Dutch NPPO conclude that Peanut stunt virus  is not seed transmitted in Phaseolus  sp. 
or Vicia  sp. The information outlin ed below was collected by MPI for this advice. No evidence 
was found that PSV is seed transmitted in Phaseolus  sp. or Vicia  sp. Therefore, the 
conclusion of this advice agrees with the Dutch NPPO.  
 
The Peanut stunt virus  is a virus in the genus Cucumovirus , family Bromoviridae  (ICTV, 
2019). A characteristic of PSV disease is the sudden outbreak of disease, with an 
unexplained origin (Schwarz et al, 2005). The virus is easily transmitted mechanically and by 
several aphid species. Symptoms of PSV i nfection include leaf mosaic, plant deformation 
and stunting. Infected plants produce fewer seed pods than healthy plants. Pods that are 
produced are small, malformed and produce few seeds (Schwarz et al, 2005). Therefore, 
infected plants rarely produce vi able seeds and seeds are unlikely to be an important source 
of viral inoculum.  
 
Evidence was found of low rates of PSV seed transmission in Arachis hypogaea  (peanut) 
(Troutman et al, 1967; Sastry, 2013). Transmission rates of 3 -4% in seeds of 2 cultivars of 
Glycine max (soybean) have been reported (Iizuka and Yunoki 1974; Sastry, 2013). As only 
the abstracts of the papers are available, it is not known how the seed transmission 
experiments were carried out.  
 
The virus is not reported to be seed transmitte d in Phaseolus  sp.. Echandi and Hebert (1971) 
collected seeds, large enough for sowing, from infected commercially grown Phaseolus  sp. 
plants ( variety Dade). The disease incidence of PSV in the field was reported to be 100%. 
The seeds were grown out in a g lasshouse and examined for disease symptoms. Of the 
2000 seedlings, no infection was observed. In a separate experiment it was observed that 
infection with PSV reduced flower and seed pod production in beans by 50 and 90% 
respectively. Iizuka and Yunoki (1 974) report that the virus is not transmitted through P. 
vulgaris  or cowpea seeds. No more recent studies were found contradicting this evidence on 
Google, Google Scholar or CAB Abstracts using the search term ‘Peanut stunt virus seed 
Phaseolus’.  
 
No evid ence was found of PSV being seed transmitted in Vicia  sp. seeds on Google, Google 
Scholar or CAB Abstracts using the search term ‘Peanut stunt virus seed Vicia’ .  
References  
• Demler, S A; Rucker, D G; De Zoeten, G A (1993) The chimeric nature of the genome 
of pea enation mosaic virus: the independent replication of RNA 2. Journal of General 
Virology, 74(1): 1‒4.  
• Echandi, E; Hebert, T T (1971) Stunt of beans incited by peanut stunt virus. 
Phytopathology, 61: 328‒330. ICTV (2019) https://talk.ictvonline.org/taxonomy/   
https://talk.ictvonline.org/taxonomy/    
• Iizuka, N; Yunoki, T (1974) Peanut stunt virus  isolated from soybeans, Glycine max 
Merr. Bulletin of the Tohoku National Agricultural Experiment Station , (47): 1‒12. 
[Abstract only]  
• Kraft, J M; Pfleger, F L (2001) Compendium of pea diseases and pests (No. Ed. 2). 
American Phytopathological Society (APS Press). NZOR (2019). Available at: 
http://www.nzor.org.nz/names/d7e1fbf8 -f846-4f18-952c -579b1a804cec  (Accessed 
6/12/19) http://www.nzor.org.nz/names/d7e1fbf8 -f846-4f18-952c -579b1a804cec  
(Accessed 6/12/19)   
Ministry for Primary Industries   RMP: Proposed Amendments to Seed for Sowing IHS  • 49 • Sastry, K S (2013) Seed -borne plant virus diseases. Springer Science & Business 
Media. Skaaf and de Zoeten (2000) Available at: 
http://www.dpvweb.net/dpv/showadpv.php?dpvno=372  (Accessed 6/12 /19) 
http://www.dpvweb.net/dpv/showadpv.php?dpvno=372  (Accessed 6/12/19)  
• Schwartz, H F; Steadman, J R; Hall, R; Forster, R L (2005) Compendium of bean 
diseases (No. Ed. 2). American Phytopathological Society (APS Press).  
• Timmerman -Vaughan, G; Larsen, R; Murray, S; McPhee, K; Coyne, C (2009) 
Analysis of the accumulation of Pea enation mosaic virus  genomes in seed tissues 
and lack of evidence for seed transmission in pea ( Pisum  sativum). Phytopathology, 
99(11): 1281‒1288.  
• Troutman, J L; Bailey, W K; Thomas , C A (1967) Seed transmission of Peanut stunt 
virus . Phytopathology, 57(11): 1280‒1281. [Abstract only]  
 
  50 • RMP: Proposed Amendments to Seed for Sowing IHS  Ministry for Primary Industries  6.4 Scientific and technical advice on whether measures are required to manage 
the risk from Potato spindle tuber viroid  (PSTV d) on seed for sowing of t he 
ornamental species Dahlia, Chrysanthemum and Diascia , eligible to import 
under IHS 155.02.05: S eeds for Sowing  
Background  
TomatoesNZ has requested MPI to assess the risks of PSTVd on Dahlia , Chrysanthemum  
and Diascia  seeds for sowing. Introduction  of PSTVd in New Zealand could  have serious 
implications on export assurances  for other important host crops (for example Solanum 
tuberosum , S. lycopersicum  and Capsicum annuum ). 
 
Summary of Advice  
• Potato spindle tuber viroid  (PSTVd) is reported to be seed -transmitted in Glebionis 
coronaria  (=Chrysanthemum coronarium ); seed -transmission has not yet been tested 
in Dahlia  and Diascia  but seems likely based on the biology of PSTVd and known 
seed -transmission of PSTVd in asymptoma tic non -Solanaceous hosts.  
• Seed -transmission is reported for a range of other hosts, such as Solanum 
tuberosum, S. lycopersicum, Capsicum annum, Petunia x hybrida , likely for Physalis 
peruviana . The biology of the viroid supports possible embryo infection  in many 
hosts.  
• PSTVd is reported as mainly asymptomatic in Dahlia , Chrysanthemum  and Diascia ; 
many other ornamental hosts are known to serve as an asymptomatic source of 
inoculum.  
• The potential for PSTVd  to establish and spread in New Zealand is likely to  be high, 
with low uncertainty.  
• The potential impact of PSTVd  to New Zealand is likely to be high, with low 
uncertainty.  
 
 
Supporting information  
 
Taxonomy and evolution  
Potato spindle tuber viroid  (PSTVd) is the type member of the family Pospiviroidae. Its 
genome (~359 nucleotides) consists of a small, circular, single -stranded RNA molecule that, 
unlike viruses, is not associated with proteins. Consequently, PSTVd relies entirely on their 
sequence,  structure and host factors for replication and propagation. PSTVd is known for 
one of the highest known mutation rates among all organisms and for a constant change in 
sequence variation throughout infection (so -called quasispecies, Adkar -Purushothama et al. 
2020) . An arbitrary level of less than 90% sequence identity and distinct biological properties 
are the main criteria for separating viroid species within a genus ( Adkar -Purushothama et al. 
2020).  PSTVd is also known as Tomato bunchy top virus , potato gothic virus , potato spindle 
viroid  and spindle tuber viroid .  
 
Biology  
Variants consisting of 356 -363 nucleotides have been described and , because of its 
extremely high mutation rate , PSTVd is highly adaptable (i.e. hosts, environment and highly 
variable in terms of symptoms) (CPC 2020). PSTVd replicates autonomously in susceptible 
plant hosts via a rolling circle mechanism. Viroids are low molecular weight infectious nucleic 
acids pre dominantly located in the nuclei of infected cells (CPC 2020). Therefore, PSTVd is 
usually found in all parts of the susceptible plant and is efficiently transmitted by propagation, 
cutting knives, contaminated sap, physical contact between healthy and dis eased plants 
(even asymptomatic), tractor wheels,  seed, pollen, irrigation water and occasionally insects, 
such as aphids (CPC 2020, Mackie et al. 2016 ). 
  
Ministry for Primary Industries   RMP: Proposed Amendments to Seed for Sowing IHS  • 51 Host range  
Severe symptoms and large -scale outbreaks are mainly known from potato, tomato and 
pepper ( Capsicum annuum ). Sometimes m ild variants of PSTVd cause no obvious 
symptoms in these hosts (CPC 2020). Reported asymptomatic hosts include avocado 
(Persea americana ), Brugmansia  spp., Chrysanthemum  sp., Calibrachoa  sp., Cestrum  spp., 
Dahlia  sp., Datura  sp., Lycianthes rantonnei , Petunia  sp., Physalis peruviana , Solanum 
pseudocapsicum , Streptosolen jamesonii , Solanum jasminoides , Solanum muricatum , sweet 
potato ( Ipomoea batatas ) and wild Solanum  spp. (CPC 2020). The experimental host range 
of PSTVd includes a wide range of Solanaceous species, as well as species from other 
families, such as Convolvulaceae and Lauraceae (CPC 2020).  
 
Potential to establish  
 
The potential for PSTVd  to establish in New Zealand is likely to be high, with low uncertainty.   
Host plants the viroid can cause considerable damage on (e.g. potatoes, capsicum, and 
tomatoes) are commonly grown in and economically important for New Zealand. Reported 
asymptomatic hosts, which may act as a source of inoculum for the viroid, such as a vocado, 
black nightshade and petunia, are also common. The viroid does not require an insect vector 
for transmission. Furthermore, the aphid described as being possibly able to transmit the 
viroid ( Macrosiphum euphorbiae ) is present in New Zealand. PSTVd i s easily spread, for 
example, through botanical seed and pollen. The New Zealand climate does not seem to be 
a limiting factor for PSTVd as it has been found on Capsicum annum  in the Auckland region 
and on Physalis peruviana  in Christchurch prior to its eradication (Lebas et al. 2005, Ward et 
al. 2010). Its global distribution (all continents, from the tropics as far north as Russia) 
reinforces this conclusion (EPPO 2020). Suitable host plants are widely distributed in New 
Zealand and PSTVd has the ability to spread asymptomatically. Thus, the likelihood to 
establish naturally in New Zealand is considered high.  
 
Potential impact  
The potential impact of PSTVd  to New Zealand is likely to be high, with low uncertainty.  
Direct i mpacts would likely occur on the tomato, potato and capsicum industry. Yield losses 
vary with host cultivar, PSTVd variety and season, but are particularly severe under dry 
conditions (CPC 2020). The general pattern is of a progressive decrease in yield as  infection 
increases. FreshFacts (2019) estimated New Zealand’s tomato exports at around 15 million 
NZD, capsicum exports at around 20 million NZD and potato exports at around 130 million 
NZD. Likely there would be additional implications from export or tr ade restrictions imposed 
by other countries and costs from eradication attempts or a response which are hard to 
estimate but would likely be high. Furthermore, indirect impacts would likely occur on other 
industries, such as the avocado industry, which cou ld face trade restrictions due to avocado 
being an asymptomatic host of PSTVd (FreshFacts 2019, 105 million NZD export value).  
 
Seedborne, seed - and pollen -transmission reports of PSTVd  
 
Many Pospiviroids, including PSTVd, are seed -transmitted due to their  low molecular weight 
and are predominately located in the nuclei of infected cells (CPC 2020). However, the rate 
of seed -transmission of Pospiviroids is also dependent on the viroid strain, host plant 
species, cultivar and distribution of viroids in seed parts ( Matsushita et al. 2018 ). For 
example, the rate of seed -transmission of PSTVd was found to be 0 –90.2 % in tomato, 0.3 % 
in Capsicum annuum  var. grossum , 0.5 % in C. annuum  var. angulosum , 1.2 % in Glebionis 
coronaria , and 81 % in Petunia  × hybrida  (Matsushita and Tsuda 2016), while no seed -52 • RMP: Proposed Amendments to Seed for Sowing IHS  Ministry for Primary Industries  transmission was observed for C. annuum  cv. Yolo Wonder (Verhoeven et al. 2020). 
Contaminated seed is an important source of PSTVd infection for crops that are grown from 
seed but efficiency of transmission of PSTVd  can be highly variable in the same and in 
different hosts (CPC 2020). Table 1 summarises published reports of seed and pollen 
transmitted incidences of PSTVd.  
 
Table 1. Reports of seed - and pollen -transmitted PSTVd.  
Host plant 
species  Seed -transmitted  Pollen-
transmitted  Reference  
Solanum 
tuberosum  yes yes Fernow et al. 1970, Hunter 
et al. 1969, Singh 1970  
S. lycopersicum  yes yes Benson and Singh 1964, 
Constable et al. 2019, 
Kryczyński et al. 1988, 
Matsushita and Tsuda 
2016, Singh 1970  
Capsicum 
annum  yes  Botermans et al. 2020, 
Constable et al. 2019, 
Matsushita and Tsuda 2016  
Glebionis 
coronaria  yes  Matsushita and Tsuda 2016  
Petunia × 
hybrida  yes Yes Matsushita and Tsuda 
2014, Yanagisawa and 
Matsushita 2017  
Physalis 
peruviana  highly likely   Ward et al. 2010 
(contaminated seed 
imported from Germany 
was considered the cause 
of the outbreak ) 
 
 
Significance of ornamental hosts in the spread of PSTVd  
Ornamental asymptomatic hosts are significant for the introduction and spread of PSTVd.  
For example, comparison of the respective nucleotide sequences of PSTVd indicated 
connections between PSTVd infections in several lots of tomato and infections in lots of the 
ornamental Solanum jasminoides  (CPC 2020). As vegetatively propagated plan ts of S. 
jasminoides  were kept in greenhouses year -round, they could serve as a permanent source 
of inoculum for tomato crops, which were removed from the greenhouse after every 
production cycle. This indicated that S. jasminoides  was the original source o f PSTVd 
infection in various outbreaks in tomato (CPC 2020).  
Recent analyses demonstrated spreading of a PSTVd population in ornamentals that 
included isolates from species like Brugmansia  sp., S. jasminoides , S. muricatum , S. 
pseudocapsicum , S. rantonneti i, Datura  sp., Chrysanthemum  sp., Cestrum  sp., Dahlia  sp., 
Petunia  sp., Matricaria chamomilla , Argyranthemum frutescens  and Diascia  sp. (citations 
within Matoušek et al. 2014).  
 
Dahlia , Chrysanthemum  and Diascia  species as asymptomatic hosts of PSTVd  
• PSTVd has been reported as being mainly asymptomatic from Dahlia  spp. (Fujiwara 
et al. 2013, IPPC 2014, Monger 2018, Tsushima et al. 2011, Tsushima et al. 2016).  
• PSTVd has been reported mainly asymptomatic from Chrysanthemum  spp. (citations 
within Matoušek et al. 2014).   
Ministry for Primary Industries   RMP: Proposed Amendments to Seed for Sowing IHS  • 53 • PSTVd has been reported mainly asymptomatic from Diascia  spp. (Matoušek et al. 
2014).  
 
Although reported as mainly asymptomatic in these ornament al host species, the same 
isolates of PSTVd have been reported to be able to induce symptoms in tomato ( Tsushima et 
al. 2016).  
 
 
Dahlia , Chrysanthemum  and Diascia  species allowed for import  
There are several species of Dahlia , Chrysanthemum  and Diascia  allowed for import under 
the specifications for seed for sowing and nursery stock (see Table 1).  
 
Table 1. Dahlia , Chrysanthemum  and Diascia  allowed for import under the import 
specifications for seed for sowing and nursery stock (Plant Biosecurity  Index 2020) . 
Dahlia spp. Chrysanthemum spp. Diascia spp. 
Dahlia coccinea  Chrysanthemum alpinum (= 
Leucanthemopsis alpina) Diascia barberae  
Dahlia coccinea x 
pinnata  Chrysanthemum anethifolium (= 
Argyranthemum foeniculaceum)  Diascia cordata (= 
Diascia barberae)  
Dahlia excelsa  Chrysanthemum arcticum (= 
Arctanthemum arcticum)  Diascia elegans  
Dahlia imperialis  Chrysanthemum atlanticum (= 
Rhodanthemum atlanticum)  Diascia fetcaniensis  
Dahlia merckii  Chrysanthemum balsamita (= Tanacetum 
balsamita)  Diascia flanagani  
Dahlia pinnata  Chrysanthemum carinatum  Diascia integerrima  
Dahlia tenuicaulis  Chrysanthemum catananche (= 
Rhodanthemum catananche)  Diascia lilacina  
Dahlia variabilis  Chrysanthemum cinerariifolium (= 
Tanacetum cinerariifolium)  Diascia mollis  
Dahlia xhortensis  Chrysanthemum coccineum (= Tanacetum 
coccineum)  Diascia patens  
 Chrysanthemum coronarium  Diascia racemulosa  
 Chrysanthemum frutescens (= 
Argyranthemum frutescens)  Diascia rigescens  
 Chrysanthemum haradjanii (= Tanacetum 
haradjanii)  Diascia stachyoides  
 Chrysanthemum hosmariense (= 
Rhodanthemum hosmariense)  Diascia tugelensis  
 Chrysanthemum indicum (= 
Dendranthema indicum)  Diascia vigilis  
 Chrysanthemum inodorum   
 Chrysanthemum leucanthemum (= 
Leucanthemum vulgare)   
 Chrysanthemum mawii (= Rhodanthemum 
gayanum)   
 Chrysanthemum maximum (= 
Leucanthemum maximum)   
 Chrysanthemum morifolium (= 
Dendranthema xgrandiflorum)   
 Chrysanthemum paludosum (= 
Leucanthemum palu dosum)   54 • RMP: Proposed Amendments to Seed for Sowing IHS  Ministry for Primary Industries   Chrysanthemum parthenium (= 
Tanacetum parthenium)   
 Chrysanthemum ptarmiciflorum (= 
Tanacetum ptarmiciflorum)   
 Chrysanthemum rubellum (= 
Dendranthema zawadskii)   
 Chrysanthemum segetum   
 Chrysanthemum weyrichii   
 
 
Seedborne/seed transmission reports ( Dahlia , Chrysanthemum  and Diascia  species)  
A seed -transmission rate of 1.2 % of PSTVd has been reported for  Glebionis coronaria 
(=Chrysanthlemum coronarium ) (Matsushita and Tsuda 2016).  
No publications about seed -transmission tests of PSTVd in Dahlia  and Diascia  species were 
found. However, seed -transmission of PSTVd in Dahlia  and Diascia  seems likely considering 
1) the biology of PSTVd (especially the low molecular weight and the ability to infect every 
susceptible plant cell including the embryo, ovules and pollen ), and 2) known seed -
transmission in asymptomatic non -Solanaceous hosts, su ch as Glebionis coronaria 
(=Chrysanthlemum coronarium ) (Matsushita and Tsuda 2016).  
 
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