Consultation : 
Proposed measures to manage  
phytoplasmas on ornamental 
plants for planting  
Importation of Nursery Stock  (155.02.06)  
 
 
 
 
 
 
 
 
 
 
 
Prepared for  public consultation   
by Plant Germplasm Imports  team  
Animal and Plant Health Directorate  
 
 
January  2024 
 
 
 
 
 
 
 
 
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 
 
1 GENERAL INFORMATION  ................................ ................................ ................................ .........................  1 
1.1 PURPOSE ................................ ................................ ................................ ................................ ......................  1 
1.2 WHO SHOULD READ THIS  ................................ ................................ ................................ ................................ . 1 
1.3 WHAT IS CHANGING  ................................ ................................ ................................ ................................ .......  1 
1.4 HOW THE CHANGES WILL AFFECT YOU  ................................ ................................ ................................ ................  1 
1.5 WHAT YOU CAN DO  ................................ ................................ ................................ ................................ ........  2 
1.6 LEGAL NOTICE ABOUT YOUR FEEDBACK AND OFFICIAL INFORMATION ACT 1982  ................................ .........................  2 
1.7 SOURCES OF INFORMATION ................................ ................................ ................................ ..............................  2 
2 PHYTOPLASMAS: PLANT PATHOGENS THAT CAN CAUSE SERIOUS DISEASES  ................................ ...........  3 
2.1 PHYTOPLASMAS ’ CLASSIFICATION  ................................ ................................ ................................ ......................  3 
2.2 PHYTOPLASMAS IN NEW ZEALAND  ................................ ................................ ................................ ....................  3 
2.3 PHYTOPLASMAS ASSESSED IN THIS PROPOSAL ................................ ................................ ................................ .......  4 
2.4 HOSTS OF THE 11 TARGET PHYTOPLASMAS ................................ ................................ ................................ ..........  6 
3 PROPOSED MEASURES FOR THE MANAGEMENT OF PHYTOPLASMAS  ................................ .....................  6 
3.1 MEASURES FOR HOSTS OF THE 11 TARGET PHYTOPLASMAS  ................................ ................................ ....................  7 
3.1.1  Addition of the 11 target phytoplasma s to quarantine pest lists  ................................ ....................  7 
3.1.2  Addition of phytosanitary measures for target phytoplasmas on 43 new ornamental hosts  .........  7 
3.1.3  Amendment of the current measures for phytoplasmas in the Rosa  schedule  ...............................  9 
3.1.4  No change to current import requirements for hosts produced under MPI -approved Dutch 
propagation schemes  ................................ ................................ ................................ ................................ .. 10 
3.2 REMOVAL OF MEASURES FOR PHYTOPLASMAS FOR ACROCOMIA , HIPPEASTRUM  AND ZANTEDESCHIA ; REMOVING FOUR 
PHYTOPLASMAS FOR ROSA ................................ ................................ ................................ ................................ ...... 10 
3.3 REGULATORY CHANGES FOR THE REMAINING 75 PHYTOPLASMAS  ................................ ................................ ..........  10 
4 HOW THE MEASURES WILL MANAGE THE RISK  ................................ ................................ .....................  14 
5 REFER ENCES  ................................ ................................ ................................ ................................ ..........  18 
APPENDIX 1: PHYTOPLASMA SUBGROUPS THAT DID NOT MEET THE CRITERIA FOR ADDITIONAL MEASURES
 ................................ ................................ ................................ ................................ ................................ .......  19 
APPENDIX 2: RISK ASSESSMENT FOR THE 11 TARGET PHYTOPLASMAS  ................................ ..........................  25 
PHYTOPLASMA TRANSMISSION  ................................ ................................ ................................ ................................ . 25 
LIKELIHOOD OF ENTRY  ................................ ................................ ................................ ................................ ............  25 
LIKELIHOOD OF EXPOSURE  ................................ ................................ ................................ ................................ .......  26 
LIKELIHOOD OF ESTABLISHMENT AND SPREAD  ................................ ................................ ................................ ..............  26 
IMPACTS IN NEW ZEALAND  ................................ ................................ ................................ ................................ ..... 26 
APPENDIX 3: HOSTS ASSOCIATED WITH THE 11 TARGET PHYTOPLASMAS  ................................ .....................  30  
Ministry for Primary Industries  Amendments to the Import Health Standard 155.02.06: Importation of Nursery Stock  • 1 1 General information  
1.1 Purpose  
(1) This document outline s proposed changes  to the Importation of Nursery Stock  
(155.02.06)  standard (the standard) to manage the risk of phytoplasmas on imported 
ornamental plants for planting  (nursery stock) . Phytoplasmas can cause disease in many  
plant species,  so they  are a pest of concern to New Zealand.  
(2) The purpose of this risk management proposal  is to:  
a) explain  how the  changes  proposed by the Ministry for Primary Industries (MPI)  manage 
the risk of phytoplasmas ; and  
b) ask for  feedback on the se proposed changes . 
(3) After we have received all your feedback and finalised the changes, we will send out a 
draft of the amended standard for you to read and give feedback on again.  
1.2 Who should read this  
(4) Read this if you are:  
a) interested in the importation of  ornamental plants for planting;  
b) an exporter of ornamental plants for planting from New Zealand;  
c) a national plant protection organisation  (NPPO) ; or 
d) a post -entry quarantine operat or. 
1.3 What  is changing  
(5) We propose adding  phytosanitary measures to manage phytoplasmas on 43 ornamental 
plant  hosts and amending the current measures for Rosa . We propose identifying 
measures by using a new approach that considers  history of trade.  
(6) We also p ropose removing some phytoplasmas from the quarantine pest list s of 
Acrocomia , Hippeastrum , Rosa  and Zantedeschia , as well as updating the regulatory 
status of the phytoplasmas assessed in this proposal.  
1.4 How the changes will affect you  
(7) We sought  to strike a balance between  effectively managing the risk of phytoplasmas 
while provid ing maximum flexibility for importers  with no  significant cost increases . 
(8) There will be some changes to the import process for importers, exporters and NPPOs.  
(9) Some of the measures  propose managing risk offshore , and those are not expected to 
significantly increase costs.  If offshore measures are not feasible , we have also 
proposed measures  that manage  risks in New Zealand . However, we expect that these 
will generally increase  costs for importers.  
(10) Overall costs will decrease for Rosa  importers . Rosa importers will also have more 
options when importing  Rosa  plant material . 2 • Ministry for Primary Industries Amendments to the Import Health Standard 155.02.06: Importation of Nursery Stock   1.5 What you can do  
(11) If you want to comment on the proposed changes , we are accepting feedback until 5  pm, 
12 March 2024. If your  feedback arrives after the closing date, we will hold it on file 
and consider it the next time we review th e standard. Email your feedback to 
Plant Imports@mpi.govt.nz . 
(12) We are particularly interested in feedback on these questions:  
a) Are our proposed measures  feasible?  If not, why  and w hich other measures would 
you propose?  
b) Do you foresee any consequences from these measures  that we have not addressed 
in this proposal?  If so, which ones?  
c) Is there a risk we have not considered?  If so, which one? Please provide scientific 
evidence to support your answer  so we can review it . 
d) Is there any other information you think we should consider before we draft  the 
changes to the standard ? 
(13) We base our requirements on the best scientific information available to us at the time, 
but knowledge is always changing. If you have  more up -to-date sci entific information 
or industry experience  that could change our conclusions, include that information in 
your feedback.  
(14) This is a public consultation. We summarise the  feedback we receive in a document 
(review  of submissions ) that includes our responses a nd details of any changes we make 
based on feedback. We then publish the review  of submissions  on our website. This 
means you can see what other people have said to us and find out what we have done 
about it. It also means your own feedback, along with you r name and organisation, will 
be online and may be read by anyone. See the legal notice below.  
1.6 Legal notice about your feedback and Official Information Act 1982  
(15) Your submission is public information, and it is MPI policy to publish submissions and 
a review of these submissions on the MPI website. Submissions may also be the subject 
of requests for information under the Official Information Act 1982 (OIA). The OIA 
specifies that information is to be made 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 being commercially sensitive or personal. Any decision to withhold 
information requested under the OIA is reviewable by the Ombudsman.  
1.7 Sources of information  
(16) This proposal  is based on information from the following MPI risk a nalyses (availa ble 
in the reference section of this proposal):  
a) Pest Risk Assessment: Phytoplasma Associated with Nursery Stock (MPI, 2021) . 
b) Technical Advice: Host association of nursery stock genera with phytoplasmas, lethal 
yellowing in the  Acrocomia  and Phoenix schedu les, and phytoplasma detection in 
asymptomatic plants (MPI, 2020) . 
c) Risk Management Proposal: Rose ( Rosa  spp.) Nursery Stock from Australia, Austria, 
Belgium, Denmark, Finland, France, Germany, Greece, Hungary, Ireland, Italy, Japan, 
Luxembourg, The Netherl ands, Norway, Portugal, Spain, Sweden, Switzerland, United 
Kingdom (MPI, 2016) .  
Ministry for Primary Industries  Amendments to the Import Health Standard 155.02.06: Importation of Nursery Stock  • 3 d) Import Risk Analysis: Rosa  Nursery Stock (MPI, 2013) . 
(17) Where information has been used that is not included in these analyses, citations are 
provided.  
2 Phytoplasmas: plant pathog ens that can cause serious 
diseases  
(18) Phytoplasmas are bacteria that can cause disease in vegetable, cereal, fruit, medicinal, 
forestry, industrial, ornamental  and New Zealand native plants . In some plants, 
phytoplasma infection can cause  sterility, yellowing, dieback and death.  Other plants 
may not have any  symptoms.  
(19) Phytoplasmas  can be transmitted by propagati ng infected material and by insect vectors. 
The m ain insect vectors are leafhoppers, planthoppers and psyllids.  
(20) Much about phytoplasmas is unknown, and researchers continue to find out new 
information (which  can result in us changing import  requirements) . Since the mid -
1990s, the number of countries where phytoplasmas  are present has been increasing, 
along with the number  of plant hosts reported for each phytoplasma . It is not yet clear 
whether  phytoplasmas are  spreading to new hosts  and countries , or whether the 
phytoplasmas  were always there  and scientists are getting better at detecting them . 
(21) From June 2018 to February 2022, we have received and assessed 128 alerts related to 
phytoplasmas  through our Emerging Risks System (ERS) . We have conducted further  
risk assessment on 30 of these alerts  to determine whether we should  amend the 
standard with measures  for phytoplasmas. This proposal addresses the 
recommendation s of some of those assessments.   
2.1 Phytoplasma s’ classification  
(22) Phytoplasmas are classified into 16Sr groups and subgroups . There are currently over 
30 recognised groups . Each group has 1 to 35 subgroups  and there are over 160 
subgroups  known to date . However, not all phytoplasmas have a formally assigned 
subgroup.  
(23) Phytoplasmas can also be classified into ‘ Candidatus Phytoplasma’ species . There are 
currently 42 recognised candidat e species. Each candidat e species corresponds to a 16S r 
subgroup, but not every subgroup has been classified into a candidat e species.  
(24) Many  phytoplasmas have  common names  (for example , ‘lethal yellowing’)  as well as 
scientific names . These names are based on the symptom s the bacteria caused in the 
plants where the disease was originally identified.  However, the common names  can be 
misleading because  the same  phytoplasma  species  often affect  multiple plant species 
and caus e different symptoms in different hosts (Liu et al., 201 8). Also, different 
phytoplasma species can induce the same symptoms in a particular host.  
2.2 Phytoplasmas in New Zealand  
(25) Only two phytoplasma  groups  are known to be present in New Zealand:  
a) 16SrIII -H Poinsettia branch -inducing; and  4 • Ministry for Primary Industries Amendments to the Import Health Standard 155.02.06: Importation of Nursery Stock   b) 16SrXII -B (‘Ca. P. australiense’) 1. 
(26) So far, t here has been  no evidence  of other phytoplasmas  in New Zealand via gene ral 
surveillance . General surveillance  includes  reporting of pathogens by the public, 
producers , industry  and our export markets. General surveillance is internationally 
recognised as a method for determining pest status (presence or absence) in a country  
(FAO, 1998 ). 
(27) MPI also has a High -Risk Site Surveillance programme  (HRSS) that targets our priority 
list of  pests and diseases of concern to plant (and aquatic) health , which  includes two 
phytoplasmas ( Ca. Phytoplasma asteris  and Grapevine flavescence dorée phytoplasma) . 
Samples from plants showing disease symptoms are sent to MPI’s Plant Health and 
Environment  Laboratory (PHEL) for identification.  Given that a generic PCR2 test is 
used for phytoplasma detection , the HRSS programme would  alert us to  the presence of 
other  phytoplasmas  too. 
2.3 Phytoplasmas assessed in this proposal  
(28) We assessed 86 phytoplasma subgroups , belonging to 19 groups , associated with 
ornamental plants for planting  eligible for importation into New Zealand . We concluded 
that: 
a) Eleven phytoplasma  subgroup s (target phytoplasmas ) meet the c onditions  to be 
considered  quarantine  pests  (regulated organisms)  on their respective hosts (Table 1). 
As such, their hosts will require management measures  in addition to our basic entry 
requirements  (section 2 of the standard ). 
b) The remaining 75 phytoplasma subgroups do not meet the c onditions  to be considered 
quarantine pests  (Appendix 1). As such, no additional management measures are being 
proposed for their plant hosts.  
Table 1: Target phytoplasmas and their current regulatory status  in New Zealand  
Phytoplasma 16Sr 
group  Phytoplasma 16Sr 
subgroup  ‘Candidatus  
Phytoplasma ’ species  Regulatory 
status  in 
ONZPR3 
I - aster yellows  N/A4 N/A Not assessed  
II - peanut witches’ 
broom  II-D - Papaya mosaic  ‘Ca. P. 
australasiaticum’  Regulated5 
II - peanut witches’ 
broom  N/A N/A Not listed  
III - X-disease  N/A N/A Not listed  
V - elm yellows  V-D - “Flavescence dorée”  N/A Regulated6 
V - elm yellows  N/A N/A Not assessed  
 
1 Strains present in New Zealand are non -regulated (see  Official New Zealand Pest Register ). These are  strains that have been  found on the 
following plant species : Fragaria  sp., Solanum  spp., Gomphocarpus fruticosus , Rubus ursinus  and Apium graveolens . 
2 Polymerase Chain Reaction.  
3 Official New Zealand Pest Register . 
4 Not assigned . 
5 Listed as ‘Candidatus Phytoplasma australasiae’ . 
6 Listed as ‘Grapevine flavescence doree phytoplasma’ .  
Ministry for Primary Industries  Amendments to the Import Health Standard 155.02.06: Importation of Nursery Stock  • 5 Phytoplasma 16Sr 
group  Phytoplasma 16Sr 
subgroup  ‘Candidatus  
Phytoplasma ’ species  Regulatory 
status  in 
ONZPR3 
VI - clover 
proliferation  VI-A - Clover proliferation  ‘Ca. P. trifolii’  Regulated  
X - apple 
proliferation  X-A - Apple proliferation 
(AP)  ‘Ca. P. mali ’ Regulated  
XII - “stolbur”  XII-A - “Stolbur”  ‘Ca. P. solani’  Regulated  
XII - “stolbur”  XII-B - Australian grapevine 
yellows (strains not in NZ)  ‘Ca. P. australiense’  Regulated7 
XII - “stolbur”  N/A N/A Not assessed  
 
(29) The 11 target phytoplasma s meet the conditions to be considered quarantine pests 
because  they:  
a) are not known to be present in New Zealand ; and  
b) are associated with plants  eligible for importation  into New  Zealan d; and  
c) have k nown hosts present in New Zealand ; and  
d) have a ‘high’ to ‘very hi gh’ likelihood ( chance ) of causing negative economic, 
environmental or sociocultural impacts in New Zealand.  This is because they can 
impact:  
i) Hosts that are  economic ally importan t to New Zealand including food  and 
forestry crops (for example , apples, grapes, onions, potatoes, tomatoes, animal 
feed, oak and pine trees).  
ii) Hosts that are important for the  environment  or society and culture  includ ing oak 
trees grown as amenity trees and hopbush /akeake  (Dodonea viscosa ); or 
e) have a ‘moderate’  likelih ood of causing negative impacts but have:  
i) ‘high’ chances of entering New Zealand, establishing a population,  and 
spreading in the country ; or 
ii) ‘moderate’ or ‘low’ chance s of entering, establishing,  and spreading, but have 
known vector species in New Zealand, with at least one vector feed ing on many 
different host plants  (it is polyphagous) . This means vectors  could spread 
phytoplasmas to multiple plant species  within the country . 
(30) See Appendix 2 for a more  detailed assessment  of the target phytoplasmas .  
(31) The remaining 75 phytoplasma subgroups do not meet the conditions to be considered 
quarantine pests because  they:  
a) are known to be present in New Zealand; or  
b) could cause ‘negligible’, ‘very low’ or ‘low’ negative economic, environmental or 
sociocultural impacts in New Zealand ; or 
c) could cause  ‘moderate’ negative impacts but have : 
i) no known hosts of economic, environmental,  or sociocultural significance for 
New  Zealand ; or 
 
7 Strains not in New Zealand . 6 • Ministry for Primary Industries Amendments to the Import Health Standard 155.02.06: Importation of Nursery Stock   ii) ‘moderate’, ‘ low’ or ‘ very low’ chances of entering, establishing, and spreading  in 
New Zealand and no known vector species in the country.  
2.4 Hosts of the 11 target phytoplasma s 
(32) Our risk assessment identified 44 plant genera  as hosts of the 11 target phytoplasmas , 
one of which ( Rosa ) is already considered  a phytoplasma host in the standard  
(Appendix 3). We identified hosts at the genus level  because : 
a) The number of p hytoplasma hosts continue to expand . 
b) Some hosts have only been identified at the genus level in scientific literature . 
c) Our current approach for plants for planting is to regulate  for pathogens at the genus 
level unless  there are specific reasons for regulating at the species level . 
(33) Host genera included in this proposal are those that:  
a) are hosts of one or more of the 11 target  phytoplasmas ; and 
b) have been actively traded (i mported into New Zealand between January 2013 and 
December 2022); or 
c) were not imported into New Zealand between those dates  but have ‘Basic’ import 
specifications in the Plants Biosecurity Index (PBI).  
(34) We did not include h osts that did not meet conditions b) or c) above as those will be 
considered in a separate  MPI project  looking into the risk management efficacy of 
inactive  plant for planting pathways . 
3 Proposed measures  for the management of  phytoplasmas  
(35) We are proposing to:  
a) Add t he 11 target phytoplasmas to the quarantine pest  lists of their respective hosts.  
b) Add p hytosanitary measures for the target phytoplasmas on 43 new ornamental host s 
using a new approach that considers history of trade  to help identify measures.  
c) Amend the current measures for phytoplasmas in the  Rosa schedule .  
d) Keep current import requirements for hosts produced under MPI -approve d Dutch 
propagation schemes.  
e) Remove measures for phytoplasmas for Acrocomia , Hippeastrum  and Zantedeschia , 
and remove four phytoplasma s for Rosa . 
f) Make regulatory changes for the remaining 75 phytoplasmas that did not meet the 
conditions to be considered qu arantine pests.  
(36) We would like your feedback on the above  six major proposed changes  to the standard. 
As noted in section 1.5, we are specifically interested in the following:  
a) Are our proposed measures feasible? If not, why and which other measures would 
you propose?  
b) Do you foresee any consequences from these measures that we have not add ressed 
in this proposal? If so, which ones?  
c) Is there a risk we have not considered? If so, which one? Please provide scientific 
evidence to support your answer  so we can review it . 
d) Is there any other information you think we should consider before we draft  the 
changes to the standard?   
Ministry for Primary Industries  Amendments to the Import Health Standard 155.02.06: Importation of Nursery Stock  • 7 3.1 Measures for hosts of the 11 target phytoplasmas  
(37) The measures we are propos ing apply only to the host genera  identified in  Appendix 3. 
We are not changing or adding  measures for phytoplasmas on hosts not listed in 
Appendix 3.  
(38) The p roposed measures consider  current evidence indicating that these  hosts show 
symptoms when infected with phytoplasmas. However, it is not clear how long it takes 
for symptoms to appear . 
3.1.1 Addition of the 11 target phytoplasmas to quarantine pest lists  
(39) We are proposing to a dd the target phytoplasmas to the quarantine pest lists of the ir 
hosts’ respective schedules in the standard using the lowest taxonomic level possible 
(from lowest to hig hest level: ‘Ca. P. species’, subgroup and group) . Hosts currently  
listed as ‘Basic ’ in the PBI will be transferred to a schedule  within the standard8.  
(40) Additionally, the target phytoplasmas that are not currently listed as ‘Regulated ’ in the 
ONZPR will be listed as such.  
(41) See Appendix 3 for detailed information on host -phytoplasma association s. 
3.1.2 Addition of p hytosanitary measures for target phytoplasmas on 43 new ornament al 
host s 
(42) We are proposing multiple options  to manage  target phytoplasmas  on the 43 new 
ornamental hosts  listed in Appendix 3. Measures have been identified using a new 
approach that considers  history of trade regarding  phytoplasma infection . We have 
called this the  ‘Level of certainty ’ approach.  
3.1.2.1  Level of certainty  approach  
(43) We are proposing this approach because:  
a) Several  hosts listed in Appendix 3 have been imported into New Zealand in large  
quantities for decades  and from countries that have  the phytoplasmas  we are 
concerned about . However,  we have never intercepted  phytoplasmas or had an 
incursion  in New Zealand . 
b) Despite the extensive history of trade of some phytoplasma hosts, New Zealand 
remains free from nearly all phytoplasmas ( except fo r two phytoplasmas ; see section 
2.2). 
(44) This indicates that either our current import requirements or the production processes in 
exporting countries , or a combination of both,  are enough to manage the risk of 
phytoplasmas in these  hosts .  
(45) The proposed appro ach allow s us to recognise this by identifying ‘high certainty ’ and 
‘low certainty ’ pathways, with a pathway being a combination ‘host – country of 
export’  (for example, Alstroemeria  from Chile) .  
(46)  High certainty pathway s are ones for which we have a high degree of confidence , based 
on an extensive history of trade, that no phytoplasmas will be present  in a shipment . 
These pathways will require n o additional measures  for the manag ement of  
 
8 Species listed as ‘Basic ’ do not  have a schedule or quarantine  pests associated with them.  8 • Ministry for Primary Industries Amendments to the Import Health Standard 155.02.06: Importation of Nursery Stock   phytoplasmas . On the contrary, low certaint y pathw ays will require  additional measures  
as we have insufficient evidence to suggest that phytoplasmas will not be present . 
(47) There is no statistical tool to help us assign  a level of certainty  to a pathway . As such, 
we made a judgment call to identify the frequency and volume of past imports that 
would allow us to confidently say that phytoplasmas are highly unlikely to be present 
on future consignments . In this sense, the higher  the frequency and the larger the 
volume , the lower the probabilities of ph ytoplasma s entering the country  without 
detection . 
(48) After exploring various options, we considered the following t o identify the se values  
(frequency and volume  of past imports ): 
a) overall history of trade of all hosts from January 2013 to December 20229; 
b) history of trade of all hosts during  the above  10 years for each  country  of export ; 
c) median volume (349,121  units) and frequency (28) of imports for the most frequently 
imported  hosts  during the above  10 years10; and  
d) evidence of safe trade , in terms of phyto plasma infection , for each country  of export . 
(49) Considering th is, we propose  using the following  volume and frequency values  to 
identify high certainty and low certainty  pathways : 
Table 2: Values  for identifying high and low certainty  pathways  
Pathway  Volume  (units)  Frequency (no. of shipments)  
High certainty  > 300,000  > 20 
Low certainty  ≤ 300,000  ≤ 20 
3.1.2.2  Pathway reclassification  
(50) To recognise changes in trade patterns, we propose allowing pathways currently 
identified as low certainty to be  reclassified  as high certainty pathways. This could 
occur if over the most recent  10 years11 our proposed values (more than 300,000 units 
and more than 20 shipments are exported to New Zealand) are achieved with no 
phytopl asmas detected in the pathway .  
(51) Similarly, a high certainty pathway could be reclassified  as a low certainty one if at any 
time phytoplasmas are detected in a shipment (either at the border or post -border), or if 
other information comes to light ( for examp le, evidence of risk changes via ERS).  
(52) The standard will be amended to reflect pathway reclassifications when required.  
3.1.2.3  Proposed measures  
(53) The measures we propose  using the Level of certainty approach  for the 43 new 
ornamental hosts of phytoplasmas are detailed in table 3, ‘Forty -three n ew hosts ’ 
section . These measures vary depending on the commodity type  (that is , whole 
plants/cuttings vs bulbs vs tissue cultures ) as they have different risk profiles ( for 
example , tissue cultures are less likely to be infected with phytoplasmas than whole 
plants) .  
 
9 Period used to consider actively traded hosts (see section 2. 4). 
10 Excluding those imported under an MPI -approved Dutch scheme  as they would skew these values . 
11 For example, for 2024 the 10-year period would be from January 2015 to December 2024 and so on.   
Ministry for Primary Industries  Amendments to the Import Health Standard 155.02.06: Importation of Nursery Stock  • 9 3.1.3 Amendment of  the current measures for phytoplasmas in the Rosa  schedule  
3.1.3.1  Variation of the Level of certainty approach  
(54) Current measures for  all Rosa  plant material (whole plants, cuttings and tissue cultures) 
include  a minimum period of six months in post-entry quarantine (PEQ) with 
mandatory testing for phytoplasmas via PCR. These measures have been in place since 
2010.  
(55) Given that all Rosa  plant mate rial imported into New Zealand since 2010 has been 
tested for phytoplasmas, we propose  using a  variation of  the Level of certainty  approach 
that considers  this testing (and not import volumes and frequency) t o identify high  
certainty pathways  within the Rosa  schedule.  
(56) As such , high certainty  pathways refer to the seven countries that have exported Rosa 
plant material to New Zealand  to date. This is because  no samples  from these countries 
have tested positive for phytoplasmas12. For these pathways n o additional measures will 
be required for manag ing phytoplasmas . The countries are : 
a) Australia  
b) Denmark  
c) France  
d) Germany  e) Ireland  
f) Netherlands  
g) United Kingdom  
(57) The remai ning 13 countries allowed in the standard  to export Rosa  to New Zealand are 
considered as low certainty pathways as we have no evidence o f their performance. As 
such, plant material coming from these countries will requi re additional measures .  
(58) To allow for the harmonisation of measures on ornamental hosts across the standard, we 
propose applying the same measures we are proposing for the 43 new ornamental 
phytoplasma hosts : additional declarations or six months in PEQ for visual inspection  
(Table 3, ‘ Rosa ’ section).   
(59) Same as for the 43 new phytoplasma hosts , we also propose allowing pathways to be 
reclassified in the same way as described in section  3.1.2.2 Pathway reclassi fication . 
3.1.3.2  Additional changes  
(60) We also propose the following  changes to the Rosa  schedule : 
a) For whole plants and cuttings :  
i) We propose c hanging the minimum PEQ period from six to three  months13. This is 
because  the extended period was put in place in 2010 to ensure that there was 
sufficient plant material for phytoplasma testing.  
ii) An extended six-month period will only apply i f plant material requires testing for  
Xylella fastidiosa (as per current requirements in  the schedule) or visual inspection 
for phytoplasma s (depending on the country of export; current proposal ).  
b) For tissue cultures : 
i) We propose removing the mandatory PEQ period  and permit to import 
requirement , as this was also put in place  to allow for phy toplasma testing.  
 
12 2023 PHEL’s laboratory information management system data 
13 A minimum period of 3 months in PEQ is the baseline period for all imported whole plants and cuttings in the standard.  10 • Ministry for Primary Industries Amendments to the Import Health Standard 155.02.06: Importation of Nursery Stock   ii) A permit to import  Rosa  tissue cultures  will only be needed if the  plant material  
require s a period in PEQ .  
3.1.4 No change to  current import requirements for hosts  produced under MPI-approved 
Dutch propagation schemes  
(61) We do not propose any changes to current import requirements of host plants  produced 
under MPI-approved Dutch propagation schemes  (Naktuinbouw and 
Bloembollenkeuringsdienst (BKD) ), other than listing the appropriate target 
phytoplasma in the quarantine pest list (Table 3, ‘Dutch schemes’  section) . This means 
that these host  plant s can continue to be imported as they have so far . This is due to our 
knowledge of and confidence in these schemes (more information  can be found in table 
4).  
3.2 For Remo val of  measures for phytoplasmas for Acrocomia , Hippeastrum  and 
Zantedeschia ; remov ing four phytoplasma s for Rosa  
(62) We propose removing current measures for ‘regulated phytoplasmas ’ in the 
Hippeastrum  and Zantedeschia  schedules (additional declarations) , and for ‘Ca. P. 
aurantifolia’ and  ‘Ca. P. prunorum’ in the  Rosa  schedule (PCR testing)  as we did not 
find any evidence  of phytoplasma -host association.  
(63) We also propose removing current  measures for the phytoplasmas that  did not meet the 
conditions  to be considered  quarantine pests (see section 2.3) : 
a) ‘Lethal yellowing ’ on Acrocomia  (additional declaration) ; and   
b) ‘Ca. P. asteris’ and Ca. P. rubi’  on Rosa  (PCR testing).  
(64) This results in the removal of four phytoplasmas from  the Rosa schedule. However, we 
also identified three new  target  phytoplasmas , in addition to ‘ Ca. P. mali’,  that meet the 
conditions to be considered quarantine pests  on this genus  (see Appendix 3 ). 
3.3 Regulatory changes for the remaining 75 phytoplasmas  
(65) For th e remaining 75 phytoplasmas that did not meet the conditions to be considered 
quarantine pests (Appendix 1) , we propose updating ONZPR14 as follows:  
a) Phytoplasmas listed as ‘Regulated’: The field ‘A ctions upon interception’ will be 
amended to indicate that no action is required on their respective hosts  (listed in 
Appendix 1).  
b) Phytoplasmas listed as ‘Not assessed’: Their status will be changed to ‘Non -
regulated’.  
c) Phytoplasmas not listed: They will be added to the ONZPR as ‘Non -regulated’.  
 
14 As per our current process, proposed regulatory status changes or additions to ONZPR are consulted with other teams at MPI to  ensure 
there are no unintended impacts on other pathways.   
Ministry for Primary Industries  Amendments to the Import Health Standard 155.02.06: Importation of Nursery Stock  • 11 Table 3: Proposed measures for ornamental hosts of  the 11 target phytoplasmas  
Pathway  Proposed measures  
Whole plants/cuttings  Bulbs  Tissue cultures  
Forty -three n ew hosts  
High certainty15 
1. Anemone from Israel  
2. Anemone  from the Netherlands  
3. Ficus  from China  
4. Gerbera  from India  
5. Narcissus  from United Kingdom  
6. Paeonia  from the Netherlands  Addition of target phytoplasmas to 
quarantine pest list  Addition of target phytoplasmas to 
quarantine pest list  Addition of target phytoplasmas to quarantine 
pest list  
Low certainty16 
1. The five genera above from all other  
countries  
 
AND  
 
2. The remaining 3 8 host genera from 
Appendix 3 from all countries  
 
[Measures based on evidence that all 
hosts show symptoms of infection 
(section 3)]  1. Addition of target phytoplasmas to 
quarantine pest list  
 
AND  
 
2a. Additional declarations:  
 
i) “[Phytoplasma] is absent from [country] 
based on ISPM 8: Determination of pest 
status in an area” OR 
ii)"The [species] plants/cuttings were 
grown at a production site where there is 
monitoring and control against vectors 
of [phytoplasma]” AND  "The [speci es] 
plants/cuttings were inspected at the 
production site during the growing season 
and found to be free from  [phytoplasma]"  1. Addition of target phytoplasmas to 
quaran tine pest list  
 
AND  
 
2a. Additional declarations:  
 
i) “[Phytoplasma] is absent from [country] 
based on ISPM 8: Determination of pest 
status in an area” OR 
ii)" The [species] plants/cuttings were 
grown at a production site where there is 
monitoring and control against vectors 
of [phytoplasma] " AND  "The [species] 
bulbs were inspected at the production site 
during the growing season and found to be 
free from  [phyto plasma]"  1. Addition of target phytoplasmas to 
quarantine pest list  
 
AND  
 
2a. Additional declarations:  
 
i) “[Phytoplasma] is absent from [country] 
based on ISPM 8: Determination of pest status 
in an area” OR 
ii)"The [species] tissue cultures derive from 
parent plants free from [phytoplasma]"  
 
OR 
 
2b. Minimum 6 months in PEQ Level 2 for 
visual inspection of sy mptom expression  
 
15 ‘High certainty ’ pathways are ones for which we have a high degree of confidence, based on an extensive history of trade, that no phytoplasmas  will be present in a shipment  (section 3.2.1) .  
16 ‘Low certa inty’ pathways are ones for which  we have insufficient evidence to suggest that phytoplasmas will not be present  in a shipment  (section 3.2.1) .  12 • Ministry for Primary Industries Amendments to the Import Health Standard 155.02.06: Importation of Nursery Stock   Pathway  Proposed measures  
Whole plants/cuttings  Bulbs  Tissue cultures  
 
OR 
 
2b. Minimum six months in PEQ Level 2 
for visual inspection of symptom 
expression   
OR 
 
2b. Minimum six months in PEQ Level 2 
for visual inspection of symptom 
expression  
Rosa  
Rosa  from:  
1. Australia  
2. Denmark  
3. France  
4. Germany  
5. Ireland  
6. Netherlands  
7. United Kingdom  1. Addition of target phytoplasmas to 
quarantine pest list  
AND  
2. Current mandatory testing for 
phytoplasmas removed   N/A (bulbs do not apply to Rosa ) 1. Addition of target phytoplasmas to 
quarantine pest list  
AND  
2. Current mandatory testing for phytoplasmas 
removed  
Rosa from the remaining 13 countries  
currently allowed in the Rosa  schedule  
 
[Measures based on evidence that Rosa  
show s symptoms of infection (section 
3)] 1. Addition of target phytoplasmas to 
quarantine pest list  
 
AND  
 
2. Current mandatory testing for 
phytoplasmas removed  
 
AND  
 
3a. Additional declarations:  
 
i) “[Phytoplasma] is absent from [country] 
based on ISPM 8: Determination of pest 
status in an area” OR 
ii)" The [species] plants/cuttings were 
grown at a production site where there is 
monitoring and control against vectors N/A (bulbs do not apply to Rosa ) 1. Addition of target phytoplasmas to 
quarantine pest list  
 
AND  
 
2. Current mandatory testing for phytoplasmas 
removed  
 
AND  
 
3a. Additional declarations:  
 
i) “[Phytoplasma] is absent from [country] 
based on ISPM 8: Determination of pest status 
in an area” OR 
ii)"The [species] tissue cultures derive from 
parent plants free from [phytoplasma]"   
Ministry for Primary Industries  Amendments to the Import Health Standard 155.02.06: Importation of Nursery Stock  • 13 Pathway  Proposed measures  
Whole plants/cuttings  Bulbs  Tissue cultures  
of [phytoplasma] " AND  "The [spec ies] 
plants/cuttings were inspected at the 
production site during the growing season 
and found to be free from  [phytoplasma]"  
 
OR 
 
3b. Minimum 6 months in PEQ Level 2 
for visual inspection of symptom 
expression   
OR 
 
3b. Minimum 6 months in PEQ Level 2 for 
visual inspection of sy mptom expression  
Dutch schemes  
Genera/species from the Netherlands : 
 
1. Alstroemeria  
2. Begonia  
3. Dianthus caryophyllus  
4. Freesia  
5. Gladiolus  
6. Lilium  
7. Narcissus  Addition of target phytoplasmas to 
quarantine pest list (applies to D. 
caryophyllus  only as per the current 
requirements in the standard)  Addition of target phytoplasmas to 
quarantine pest list (applies to all genera 
except for D. caryophyllus , as per the 
current requirements in the standard)  N/A (tissue cultures are not imported under 
Dutch schemes)  
 14 • Ministry for Primary Industries Amendments to the Import Health Standard 155.02.06: Importation of Nursery Stock   4 How the measures will manage  the risk 
(66) Table 4 summarises how the measures we  are proposing will manage the  risk of 
phytoplasmas . It also comments on the impacts we think the  changes  will have on  
importers.  
(67) If infected plants were imported into New Zealand, they may need to be reshipped or  
destroyed to prevent the spread of phytoplasmas. However, the best course of action 
will be determined on a case -by-case basis.  
 
   
Ministry for Primary Industries  Amendments to the Import Health Standard 155.02.06: Importation of Nursery Stock  • 15 Table 4: Rationale and impact of the proposed measures for the management of phytoplasmas  
Proposed measures  How the risk will be managed  Changes for importers  
ONZPR update for the 75 
remaining phytoplasmas  The 75 remaining phytoplasmas do not meet the conditions to be considered 
quarantine pests. Adding them to ONZPR as ‘Non -regulated’ or with no 
‘Actions upon interception’, as appropriate, will ensure no unnecessary delays 
are experienced at the border or post -border if they are intercepted.  This is common procedure and does not 
affect importers directly.  
Addition of the 11 target 
phytoplasmas to quarantine 
pest lists  The 11 target phytoplasmas meet the conditions to be considered quarantine 
pests, so they will b e added to their respective hosts’ quarantine pests list.  
Even if the hosts do not have measures for phytoplasmas ( for example , hosts 
imported under MPI -approved Dutch schemes), this will ensure that measures 
such as destruction of plant material  can be q uickly applied if phytoplasmas are 
detected . It will also ensure that consignments are not exported to New Zealand 
if phytoplasmas are found prior to export.  This is common procedure and does not 
affect importers directly.  
Use Level of certainty 
approach  This approach uses  history of trade to identify management measures for 
phytoplasmas on ornamental hosts. By considering volume and frequency of 
imports, we can identify pathways for which we can  confidently say that 
phytoplasmas are highly unlike ly to be present . 
Although this approach uses past trade information as an indication of future 
risks in a pathway, we acknowledge risks can change. We expect to be made 
aware of any changes that would require us to re -assess this approach, and 
resulting m anagement measures, through our ERS, HRSS programme or through 
direct communications with our stakeholders and trading partners.  
This approach also recognises changes in safe trade patterns, allowing us to 
reclassify high and low certainty pathways  if phytoplasmas were detected.  This approach does not affect importers 
directly. We will monitor  the high and 
low certainty  pathways usi ng inhouse 
data analytics , and will amend the 
standard to account for changing 
patterns of trade or other changes in risk .  
High certainty pathways: no 
additional measures  These pathways have been active for decades with no phytoplasma interceptions . 
The volumes and frequencies of imports  associated with these pathways are 
large enough that we have confidence that our measures and the exporting 
countries systems are working well  in managing phytoplasmas . As such, no 
additional measures are required.  High certainty pathways will not require  
any additional  measures for 
phytoplasmas, so there should be no 
changes for importers  who use these 
pathways .  16 • Ministry for Primary Industries Amendments to the Import Health Standard 155.02.06: Importation of Nursery Stock   Proposed measures  How the risk will be managed  Changes for importers  
Howev er, if circumstances were to change and any of these pathways were no 
longer safe ( for example , phytoplasma are intercepted), then we would reclassify 
them as  low certainty  pathway s. This means that additional measures for the 
management of phytoplasmas wo uld be required.  
Low certainty pathways: 
additional declarations  The endorsement of any of the proposed  additional declarations on phytosanitary 
certificates will allow for trade to occur safely as these declarations will certify 
that a country is free from phytoplasmas or that the potential risks can be 
managed by production processes. For the latter, given that hosts show 
symptoms of infection, vector control and visual inspection during the growing 
season will give us assurance the consignment is free from phytoplasmas.  
If the declarations are endorsed, then there will be no other changes to t he 
current requirements in the standard  (for example, commodities can continue to 
be given clearance on arrival if that is currently the case).  
If new evidence comes to light showing that hosts can be asymptomatic, we 
would re -assess the appropriateness of the additional declarations.  Importers will need to ensure that the 
exporting country’s National Plant 
Protection Organisation (MPI’s 
counterparts) can endorse any of these 
declarations in the phytosanitary 
certificate.  
The country freed om declaration should 
be possible for countries where the 
target phytoplasmas have not been 
recorded as present.  
The production processes declarations  
should be possible from countries where 
these pathogens are known to occur but 
where production systems ensure the 
hosts are free from phytoplasmas.  
Low certainty pathways: 
minimum 6 months in Level 
2 PEQ for visual inspections  If none of the proposed additional declarations can be endorsed on phytosanitary 
certificates, a minimum period of six months in PE Q will be required for visual 
inspection of symptom expression.  
Given that hosts show symptoms of infection, visual inspection should be 
enough to detect infected plants. However, as it is not clear how long it takes for 
symptoms to appear, we propose dou bling the minimum PEQ period from three  
to six months, which is the same PEQ length recommended by PHEL when 
testing plant material for phytoplasmas via PCR. Considering that imported 
plants have been grown in the exporting country and that no diseased pla nts are 
used for propagation, we believe six months in quarantine should be enough to This should be feasible for importers of 
whole plant or cuttings, as these 
commo dity types already require a 
minimum period of three  months in PEQ 
Level 2. There would be additional costs 
related to the extra three  months.  
Costs could be significantly higher  for 
bulb and tissue culture importers  as 
these commodities do not all require 
PEQ  or require Level 1 .   
Ministry for Primary Industries  Amendments to the Import Health Standard 155.02.06: Importation of Nursery Stock  • 17 Proposed measures  How the risk will be managed  Changes for importers  
manage potential risks from phytoplasmas. However, if new information comes 
to light showing that it is not enough, then we would re -assess this measure.  
The structural r equirements of Level 2 PEQ facilities provide appropriate control 
against insect vectors of phytoplasmas, which will avoid their spread if infected 
plant s were to be imported.  MPI expects that these costs can be 
avoided  by providing any of the 
proposed additional declarations . 
MPI -approved Dutch 
schemes: keep current 
import requirements  Bulbs and whole plants produced under these schemes have b een allowed entry 
into New Zealand since at least 1993. We are well aware of how these schemes 
operate , based on previous visits to the Netherlands and discussions with Dutch 
authorities. As such, we have confidence in the Dutch NPPO  oversight of these 
schemes.  
We are satisfied that the current measures will manage the risk of phytoplasmas 
on these hosts. However, i f phytoplasmas are detected , we would re -assess this 
approach.  Plant hosts imported under a Dutch 
scheme will not require additional 
measures for phytoplasmas, so there 
should be no changes  for importers.  
Rosa : amend current 
measures  Since 2010 all Rosa  plant material imported to New Zealand has tested negative 
for the presence of phytoplasmas. As all this plant material has been exported 
from seven countries17, we are confident that they can be considered as high 
certainty pathways for the importation o f Rosa .  
Rosa  imported from the remaining 13  countries  allowed in the standard will be 
considered as low certainty pathways as we have no information on the 
performance of these countries.  
However, if safe trade patterns  change,  we would reclassify high a nd low 
certainty pathways as needed.  These changes should reduce costs for 
Rosa  importers and allow more 
flexibility when importing Rosa  plant 
material.  
 
 
17 Australia, Denmark, France, Germany, Ireland, Netherlands, United Kingdom  18 • Ministry for Primary Industries Amendments to the Import Health Standard 155.02.06: Importation of Nursery Stock   5 References  
FAO (1998) International Standard for Phytosa nitary Measures (ISPM) No. 8. Determination 
of pest status in an area. Secretariat of the International Plant Protection Convention, Food 
and Agricultural Organization of the United Nations; Rome, Italy.  
Liu, J ; Gopurenko, D; Fletcher, M J; Johnson, A C; Gurr, G  M (201 8) Corrigendum: 
Phytoplasmas –The “ crouching tiger ” threat  of Australian plant pathology . Frontiers in Plant 
Science  8: 599. 
MPI (2013) Import Risk Analysis: Rosa Nursey Stock from All Countries . Ministry for 
Primary Industries; Wellington, New Zealand.  https://www.mpi.govt.nz/dmsdoc ument/12903 -
Rosa -Nursery -Stock -from -All-Countries -Risk-Analysis   
MPI (2016) Risk Management Proposal: Rose (Rosa spp.) Nursery Stock  from Australia, 
Austria, Belgium, Denmark, Finland, France, Germany, Greece, Hungary, I reland, Italy, 
Japan, Luxembourg, The Netherlands, Norway, Portugal, Spain, Sweden, Switzerland, United 
Kingdom . Ministry for Primary Industries; Wellington, New Zealand.  
https://www.mpi.govt.nz/dmsdocument/12273 -risk-management -proposal -rose-rosa-spp-nursery -
stock -from -approved -countries   
MPI (2020) Technical advice on: Host association of nursery stock genera with 
phytoplasmas, lethal yellowing in the Acrocomia and Phoenix schedules, and phytoplasma 
detection in asymptomatic plants . Ministry for Primary Industries; Wellington, New Zealand . 
MPI (2021) Pest Risk Assessment: Phy toplasma Associated  with Nursery Stock . Ministry for 
Primary Industries; Wellington, New Zealand .   
Ministry for Primary Industries  Amendments to the Import Health Standard 155.02.06: Importation of Nursery Stock  • 19 Appendix 1: Phytoplasma subgroups that did not meet the 
criteria for additional measures  
The following phytoplasma subgroups do not meet the conditions to be  considered quarantine 
pests because they  (section 2.3) :  
a) are known to be present in New Zealand; or  
b) could cause ‘negligible’, ‘very low’ or ‘low’ negative economic, environmental or 
sociocultural impacts in New Zealand ; or 
c) could cause ‘moderate’ negative impacts but have:  
i) no known hosts of economic, environmental, or sociocultural significance for New 
Zealand; or  
ii) ‘moderate’, ‘low’ or ‘very low’ chances of entering, establishing, and spreading in 
New Zealand and no known vector species in the country.  
16Sr Group  16Sr Subgroup  ‘Candidatus  
Phytoplasma’ 
species  Regulatory 
status in 
ONZPR  Host  genus18 
I - aster 
yellows  I-A - aster yellows 
witches’ broom (AY -
WB)  N/A Regulated  Alpinia  
Chrysanthemu
m  
Coreopsis  
Dahlia  
Gladiolus  
Helichrysum  
Hyacinthus  
Hydrangea  
Limonium  
Monarda  
Petunia  
Phlox  
Rudbeckia  
Scabiosa  
Veronica  
Yucca  
I - aster 
yellows  I-AB newly described   N/A Not listed  N/A 
I - aster 
yellows  I-AD newly described  N/A Not listed  N/A 
I - aster 
yellows  I-AF newly described  N/A Not listed  N/A 
I - aster 
yellows  I-AH newly described  N/A Not listed  N/A 
I - aster 
yellows  I-AI newly described  N/A Not listed  N/A 
I - aster 
yellows  I-A-J newly described  N/A Not listed  N/A 
I - aster 
yellows  I-B - aster yellows 
(MAY)  ‘Ca. P. asteris’  Regulated  Acer  
Alstroemeria  
Argyranthemu
m 
Bidens  
 
18 We propose to update ONZPR to not e that these hosts do not require ‘Action upon interception’.  20 • Ministry for Primary Industries Amendments to the Import Health Standard 155.02.06: Importation of Nursery Stock   16Sr Group  16Sr Subgroup  ‘Candidatus  
Phytoplasma’ 
species  Regulatory 
status in 
ONZPR  Host  genus18 
Chrysanthemu
m  
Coreopsis  
Cyclamen  
Dahlia  
Echinacea  
Euphorbia  
Gladiolus  
Helichrysum  
Hyacinthus  
Hydrangea  
Jasminum  
Lavandula  
Lilium  
Limonium  
Monarda  
Ocimum  
Portulaca  
Primula  
Ranunculus  
Rosa  
Scabiosa  
Senecio  
Spiraea  
Verbena  
I - aster 
yellows  I-B - related  N/A Not listed  N/A 
I - aster 
yellows  I-C - clover phyllody 
(CPh)  N/A Regulated  Alstroemeria  
Anemone  
Cyclamen  
Echinacea  
Euphorbia  
Lilium  
Limonium  
Ranunculus  
Rhododendron  
I - aster 
yellows  I-D - paulownia 
witches’ broom (PaWB)  N/A Not listed  N/A 
I - aster 
yellows  I-L - aster yellows 
(AV2192)  N/A Not listed  N/A 
I - aster 
yellows  I-M - aster yellows 
(AVUT)  N/A Regulated  Gladiolus  
Hyacinthus  
Limonium  
Phlox  
I - aster 
yellows  I-S - pepper little leaf 
(PeLL)  N/A Not listed  N/A 
I - aster 
yellows  I-T - tomato little leaf 
(ToLL)  N/A Not listed  N/A 
I - aster 
yellows  I- newly described  N/A Not listed  N/A 
I - aster 
yellows  I-(B/L)L newly 
described  N/A Not listed  N/A  
Ministry for Primary Industries  Amendments to the Import Health Standard 155.02.06: Importation of Nursery Stock  • 21 16Sr Group  16Sr Subgroup  ‘Candidatus  
Phytoplasma’ 
species  Regulatory 
status in 
ONZPR  Host  genus18 
II - peanut 
witches’ 
broom  II-A - peanut witches’ 
broom (PnWB)  N/A Not listed  N/A 
II - peanut 
witches’ 
broom  II-B - lime witches’ 
broom (WBDL)  ‘Ca. P. 
aurantifolia’  Regulated  Dianthus  
II - peanut 
witches’ 
broom  II-C - faba bean 
phyllody (FBP)  N/A Not assessed  N/A 
II - peanut 
witches’ 
broom  II-E - picris echioides 
phyllody (PEY)  N/A Not assessed  N/A 
II - peanut 
witches’ 
broom  II-P - Cuban papaya 
phytoplasma  N/A Not listed  N/A 
II - peanut 
witches’ 
broom  II-W newly described  N/A Not listed  N/A 
II - peanut 
witches’ 
broom  II-Z newly described  N/A Not listed  N/A 
III - X-disease  III-A - peach X -disease 
(PX11CT1)  ‘Ca. P. pruni’  Regulated  Aralia  
Euphorbia  
Gentiana  
Pelargonium  
III - X-disease  III-B - clover yellow 
edge (CYE)  N/A Regulated  Crotalaria  
Echinacea  
Gaillardia  
III - X-disease  III-E - spiraea stunt 
(SP1)  N/A Not assessed  N/A 
III - X-disease  III-F - milkweed 
yellows (MW1)  N/A Not assessed  N/A 
III - X-disease  III-H - poinsettia 
branch -inducing (PoiBI)  N/A Not assessed  N/A 
III - X-disease  III-J - chayote witches’ 
broom (ChWBIII)  N/A Not listed  N/A 
III - X-disease  III-L - cassava frog skin 
disease (CFSD)  N/A Not listed  N/A 
III - X-disease  III-X - conyza  witches’ 
broom  N/A Not listed  N/A 
IV - coconut 
lethal 
yellowing  IV-B - Yucatan coconut 
lethal decline (LDY)  N/A Not assessed  N/A 
IV - coconut 
lethal 
yellowing  IV-D - Texas phoenix 
decline (TPD)  N/A Not listed  N/A 
IV - coconut 
lethal 
yellowing  IV-F - washingtonia 
robusta  decline  N/A Not listed  N/A 22 • Ministry for Primary Industries Amendments to the Import Health Standard 155.02.06: Importation of Nursery Stock   16Sr Group  16Sr Subgroup  ‘Candidatus  
Phytoplasma’ 
species  Regulatory 
status in 
ONZPR  Host  genus18 
IV - coconut 
lethal 
yellowing  N/A N/A Not listed  N/A 
V - elm 
yellows  V-A - elm yellows (EY)  ‘Ca. P. ulmi’  Not assessed  N/A 
V - elm 
yellows  V-B - jujube witches’ 
broom (JWB -G1) ‘Ca. P. ziziphi’  Not assessed  N/A 
V - elm 
yellows  V-B1 newly described  N/A Not listed  N/A 
V - elm 
yellows  V-E - rubus stunt (RuS)  ‘Ca. P. rubi’  Regulated  Rosa  
VI - clover 
proliferation  VI-A- related  N/A Not listed  N/A 
VI - clover 
proliferation  VI-D - periwinkle little 
leaf (PLL -Bd) N/A Not assessed  N/A 
VI - clover 
proliferation  VI-F - catharanthus 
phyllody (CPS)  N/A Not listed  N/A 
VI - clover 
proliferation  VI-H - portulaca little 
leaf phytoplasma (PLL -
Ind) N/A Not listed  N/A 
VI - clover 
proliferation  N/A N/A Not listed  N/A 
VII - ash 
yellows  VII-A - ash yellows 
(AshY)  ‘Ca. P. fraxini’  Regulated  Paeonia  
Polygonum  
VII - ash 
yellows  VII-B - erigeron 
witches’ broom (ErWB)  N/A Not listed  N/A 
VII - ash 
yellows  VII-C - Argentinian 
alfalfa witches’ broom 
(ArAWB)  N/A Not listed  N/A 
VII - ash 
yellows  N/A N/A Regulated  Hypericum  
IX - pigeon 
pea witches’ 
broom  IX-A - pigeon pea 
witches’ broom (PPWB)  N/A Not listed  N/A 
IX - pigeon 
pea witches’ 
broom  IX-C - naxos periwinkle 
virescence (NAXOS)  N/A Not listed  N/A 
IX - pigeon 
pea witches’ 
broom  IX-D - almond witches’ 
broom (AlWB)  N/A Not listed  N/A 
IX - pigeon 
pea witches’ 
broom  IX-F - almond and stone 
fruit witches’ broom 
(N27 -2) N/A Not listed  N/A 
IX - pigeon 
pea witches’ 
broom  IX-H - sarson phyllody  N/A Not listed  N/A 
IX - pigeon 
pea witches’ 
broom  IX-J newly described  N/A Not listed  N/A  
Ministry for Primary Industries  Amendments to the Import Health Standard 155.02.06: Importation of Nursery Stock  • 23 16Sr Group  16Sr Subgroup  ‘Candidatus  
Phytoplasma’ 
species  Regulatory 
status in 
ONZPR  Host  genus18 
IX - pigeon 
pea witches’ 
broom  IX- newly described  N/A Not listed  N/A 
IX - pigeon 
pea witches’ 
broom  N/A N/A Not listed  N/A 
X - apple 
proliferation  N/A N/A Not listed  N/A 
XI - rice 
yellow dwarf  N/A N/A Not assessed  N/A 
XI - rice 
yellow dwarf  XI-E - cirsium 
phytoplasma  ‘Ca. P. cirsii’  Regulated  Dahlia  
XII - “stolbur”  XII-D - Japanese 
hydrangea phyllody  ‘Ca. P. 
japonicum’  Regulated  Hydrangea  
 
XII - “stolbur”  XII-E - yellows diseased 
strawberry (StrawY)  ‘Ca. P. 
fragariae’  Regulated  Acer  
XII - “stolbur”  XII-F - “bois noir” (BN -
Op30)  N/A Not listed  N/A 
XIII - Mexican 
periwinkle 
virescence  XIII-F - strawberry red 
leaf N/A Not listed  N/A 
XIV - 
Bermuda grass 
white leaf XIV-A - Bermuda grass 
white leaf (BGWL)  ‘Ca. P. 
cynodontis’  Not assessed  N/A 
XIV - 
Bermuda grass 
white leaf  N/A N/A Not listed  N/A 
XV - hibiscus 
witches’ 
broom  XV-A - hibiscus 
witches’ broom 
(HibWB)  ‘Ca. P. 
brasiliense’  Regulated  Crotalaria  
Hibiscus  
XV - hibiscus 
witches’ 
broom  XV- newly described  N/A Not listed  N/A 
XV - hibiscus 
witches’ 
broom  N/A N/A Not listed  N/A 
XXII  - lethal 
yellowing -type XXII -A - lethal 
yellowing Mozambique 
(LYDM 178)  ‘Ca. P. 
palmicola’  Not listed  N/A 
XXIX  - cassia 
witches’ 
broom  XXIX -B - bindweed 
witches’ broom 
(RBiWB)  N/A Not listed  N/A 
XXXII  - 
Malaysian 
periwinkle 
virescence and 
phyllody  XXXII -A - Malaysian 
periwinkle virescence 
(MaPV)  ‘Ca. P. 
malaysianum’  Regulated  Elaeocarpus  24 • Ministry for Primary Industries Amendments to the Import Health Standard 155.02.06: Importation of Nursery Stock   16Sr Group  16Sr Subgroup  ‘Candidatus  
Phytoplasma’ 
species  Regulatory 
status in 
ONZPR  Host  genus18 
XXXII  - 
Malaysian 
periwinkle 
virescence and 
phyllody  XXXII -C - Malayan oil 
palm (MOP)  N/A Not listed  N/A 
Not classified. 
From 
Cenchrus  Not classified. From 
Cenchrus  N/A Not listed  N/A 
Not classified. 
From 
Gentiana  Not classified. From 
Gentiana  N/A Not listed  N/A 
 
   
Ministry for Primary Industries  Amendments to the Import Health Standard 155.02.06: Importation of Nursery Stock  • 25 Appendix 2: Risk assessment for the 11 target phytoplasmas  
Phytoplasma t ransmission  
Phytoplasmas are transmitted by two main mechanisms: propagation of infected material and 
insect vectors. In general, leafhoppers , planthoppers , and psyllids , which feed on the phloem 
tissues of infected plants, are the main vectors of phytoplasmas.  
A single phytoplasma may be dispersed naturally by its vectors within a habitat patch or from 
one patch to another. A single phytoplasma may also be d ispersed between plants of the same 
species or plants of different species, depending on the movement and feeding habits of 
vectors. Aerial drift of vectors can result in dispersal distances of up to hundreds or thousands 
of kilometres , along with human -assisted movement of infected plant material and/or vectors .  
Most of the target phytoplasmas  have vector species present and widespread in New Zealand. 
Those that do not , have either ‘high’ or ‘ very high’ potential s to cause  negative impacts  in the 
country . The vector species and the phytoplasmas they transmit are : 
a. Arawa variegata : 16SrXII -B 
b. Batracomorphus angustatus  (green jassid ): 16Sr II-N/A 
c. Batracomorphus punctatus : 16Sr I-N/A, 16Sr III-N/A, 16Sr VI-A 
d. Orosius argentatus (common brown leafhopper):  16Sr II-D, 16Sr II-N/A, 16Sr VI-A 
e. Philaenus spumarius (meadow spittlebug) : 16Sr III-N/A, 16Sr XII-A  
f. Zeoliarus atkinsoni : 16SrXII -B 
Phytoplasmas can also be transmitted by propagation techniques such as grafting, budding 
and micropropagation. Some plants can show no symptoms  or symptoms may take months to 
years to develop. Using these types of  plants for propagation can still spread ph ytoplasmas.  
Likelihood of entry  
The likelihood  of entry for the target phytoplasmas ranges from ‘ moderate ’ to ‘high’ 
(Table  5).  
Forty -four ornamental plant genera are known hosts of the target phytoplasmas (Appendix 3). 
These hosts are eligible for importation into New  Zealand from all countries  under the 
standard  (except for some hosts, such as Alstroemeria  and Rosa ). The target phytoplasma s 
have been reported in more than 90  countries so far , across  all continents . 
Phytoplasmas can be associated wi th all types of plants for planting , including cuttings, 
budwood, bulbs and tissue culture.  All but four of the identified hosts have been imported into 
New Zealand as plants for planting  between January 2013 and December  2022 (Appendix 3). 
Humans moving infected propagation materials is thought to play a major role in the long -
distance spread of phytoplasmas. A plant for planting is living tissue  that humans actively 
help to survive , meaning that  phytoplasmas are likely to survive transport in plants for 
planting . 
Plants for planting of the 44 host genera can be imported without post -entry quarantine (PEQ) 
or into either level 1, 2 or 3 PEQ . These hosts show symptoms of infection so visual 
inspection should be enough to detect infected plants . However, it is unknown how long it 
takes for symptoms to appear. As such, p hytoplasmas could enter the country on plants 
without  symptoms of infection if no PEQ was required or if the  PEQ period was  not long 
enough . 26 • Ministry for Primary Industries Amendments to the Import Health Standard 155.02.06: Importation of Nursery Stock   Likelihood of exposure  
The likelihood  of the target phytoplasmas  being exposed to a suitable host is ‘high ’ 
(Table  5).  
When a pest or pathogen arrives in a new area, it usually needs to come into contact with a 
growing host plant to establish a population.  In the case of plants for planting, imported plant 
material is maintained in a habitat favourable for plant growth and is likely to be multiplied in 
substantial numbers. Promoting the survival of the plant material also promotes the survival 
of any pathogens  that may be on the plant . 
Likelih ood of establishment  and spread  
The likelihood the phytoplasmas  establishing a population is ‘high ’ (Table 5). 
Establishment depends on the ability of the pathogen to move to other hosts. This likelihood 
depends on many factors, such as the availability of hosts  and the ways the pathogen can 
spread .  
All the target phytoplasmas  have known hosts available to them in  New Zealand ( Table 5). 
The host range of phytoplasmas depend s on the feeding habits and host range of their vectors, 
which means phytoplasmas often  have a very broad host range and can move to unrelated 
species  (although in some cases the host range is na rrow as the vectors only feed on a 
restricted number of hosts) .  
Phytoplasmas entering New Zealand need a suitable vector to establish a population  naturally . 
The target phytoplasmas have known insect vector species present in New Zealand, and they 
all hav e at least one polyphagous vector which feeds on a broad range of hosts.  
Phytoplasmas are present worldwide , so the New Zealand climate is unlikely to limit their 
establishment. However, their symptom expression on host plants or impacts may vary 
depending  on climate . 
Although symptomatic plants are unlikely to be used for propagation, infected plants with an 
early infection or no obvious disease expression (asymptomatic) could be. Moving infected 
plants or plant material through the country will increase t he spread and exposure to potential 
vectors.  
Impacts in New Zealand  
The magnitude of the impacts for the target phytoplasmas  ranges from ‘moderate’ to 
‘very high’ . 
The target phytoplasmas  have the potential to cause significant economic, sociocultural and 
environmental impacts if they become established in New Zealand, with the magnitude of 
those impacts depending on their host range.  
These phytoplasmas  have been reported overseas on several crops that are agriculturally or 
horticulturally important to New Zealand. For example : 
a. Grapes: export value of $ 2.4 billion as wine  to May 202319 
b. Apples: export value of $ 902 million  for 2022/2320 
 
19 New Zealand wine (2023) 2023 Vintage will support strong demand for New Zealand wine . 2023 Vintage will support strong demand for 
New Zealand wine | New Zealand Wine (nzwine.com)  
20 Fresh Facts (2023) New Zealand’s Fresh Fruit & Vegetable Industry. United Fresh New Zealand Incorporated. Fresh -Facts -–-Online -
version -2023.pdf (unitedfresh.co.nz)  
  
Ministry for Primary Industries  Amendments to the Import Health Standard 155.02.06: Importation of Nursery Stock  • 27 c. Onions: export val ue of $ 182.5  million, domestic sales value of $3 8 million  for 
2022/2320 
d. Potatoes: export value of $1 16.9 million , domestic sales value of $814.3 million  for 
2022/2320 
e. Tomatoes: export value of $ 3.8 million  for 2022/2320 
Crop losses vary depending on the phytoplasma and affected host. For example, phytoplasma s 
in the  16SrXII group have caused  serious disease among  potatoes in southeastern Europe, 
Russia and the Mediterranean region. Phytoplasmas in this  group can cause yie ld losses of 
30–80% and can also reduce seed potato quality. They  can also cause yield losses of up to 
60% in tomato, 90% in pepper, 100% in celery and 40 –90% in maize.  
Grapevine yellows phytoplasmas  belonging to various groups, such as 16SrXII and 16SrII I, 
can cause whitening and desiccation of flowers and grape bunches, drastically reducing yield. 
Crop losses of 20 –40% were reported  during an outbreak  in Slovenia . 
Flavescence dorée phytoplasma (16SrV) can decrease grapevine vitality, yield and wine 
quali ty. In the absence of control measures, the numbers of infected vines can reach 80 –100% 
within a few years. Flavescence dorée phytoplasma has destroyed large viticultural areas in 
France and Corsica and suppressed the crop from these areas since the 1950s . 
Apple proliferation phytoplasma (‘ Ca. P. mali’) can affect almost all apple varieties and can 
cause reduction in fruit size of up to 50%, fruit weight up to 63 –74%, as well as a reduction in 
fruit quality (through reduction in sugar and acid content) and tree vigour. Infection with 
apple proliferation phytoplasma can also increase the susceptibility of infected trees to other 
diseases. In some cases,  infection can le ad to tree death . 
 
 28 • Ministry for Primary Industries Amendments to the Import Health Standard 155.02.06: Importation of Nursery Stock   Table 5: Risks associated with the 11 target phytoplasmas  
Phytoplasma 16Sr 
subgroup  Likelihood of phytoplasma  
Impact type  Potential i mpact 
magnitude  Entry  Exposure  Establishment  
I-N/A High  High  High  Economic:  
Apples, capsicums, carrots, garlic, grapes, onions, 
potatoes, tomatoes, the dairy industry1, the forestry 
industry2 
 
Environmental/ sociocultural:  
Dodonaea viscosa3, poplars  and oaks4 Moderate  
II-D  
(‘Ca. P. australasiaticum’ ) 
 High  
 High  
 High  
 Economic:  
Aubergines, capsicums, carrots, grapes, lettuces, 
mandarins, potatoes, pumpkins, tomatoes, the dairy 
industry Moderate  
 
II-N/A  
 High  
 High  
 High  
 Economic:  
Aubergines, capsicums, carrots, grapes, lettuces, 
mandarins, potatoes, pumpkins, tomatoes, the dairy 
industry  Moderate  
 
III-N/A Moderate  High  
 High  
 Economic:  
Aubergines, carrots, garlic, grapes, peaches, 
potatoes, tomatoes, the dairy industry Moderate  
 
V-D - “Flavescence 
dorée”  Moderate  High  Low Economic:  
Grapes  High  
V-N/A Moderate  High  Moderate  Economic:  
Grapes  Very high   
Ministry for Primary Industries  Amendments to the Import Health Standard 155.02.06: Importation of Nursery Stock  • 29  
1 Through impacting clover and/or lucerne (crops of importance to the dairy industry) . 
2 Through impacting oak species grown in New Zealand as minor plantation trees . 
3 A species native to New Zealand, common in home gardens, which was historically used to make weapons and garden implements by M āori 
4 Grown as amenity trees in New Zealand . 
5 One of the most widely cultivated New Zealand native trees and popular as an ornamental tree .  
 Phytoplasma 16Sr 
subgroup  Likelihood of phytoplasma  
Impact type  Potential i mpact 
magnitude  Entry  Exposure  Establishment  
VI-A 
(‘Ca. P. trifolii’ ) Moderate  
  
 High  
 High  
 Economic:  
Aubergines, capsicums, lettuces, potatoes, 
tomatoes, the dairy industry Moderate  
 
X-A 
(‘Ca. P. mali’) High  High  Low Economic:  
Apples, peaches,  High  
XII-A 
(‘Ca. P. solani’ ) High  
 High  
 High  
 Economic:  
Grapes, potatoes, tomatoes  Very high  
 
XII-B 
(‘Ca. P. australiense’ ) Moderate  High  High  Economic:  
Strawberries, grapes  
 
Environmental/ sociocultural:  
Cordyline australis  (cabbage tree)5 High  
XII-N/A Moderate  High  Moderate  Economic:  
Potatoes, tomatoes, grapes, strawberries  Very high  30 • Ministry for Primary Industries Amendments to the Import Health Standard 155.02.06: Importation of Nursery Stock   Appendix 3:  Hosts associated with the 11 target phytoplasma s  
The h ost in bold  is not a new host as it already ha s measures for phytoplasmas in the 
standard.  
Host genus  Import quantity between 
2013 –2022 (units1) Target phytoplasma  to be 
managed2 
Adenium  0 ‘Ca. P. australasiaticum’  
Alstroemeria  825,868  16Sr I - aster yellows  
‘Ca. P. solani’  
Anemone  10,312,519  16Sr I - aster yellows  
Begonia  950,429 16Sr III - X-disease  
Brachyscome  896 16Sr I - aster yellows  
Chrysanthemum  240 16Sr I - aster yellows  
16Sr II - peanut witches’ broom  
‘Ca. P. australasiaticum’  
‘Ca. P. solani’  
Crotalaria  0 16Sr I - aster yellows  
16Sr II - peanut witches’ broom  
16SrV - elm yellows   
Cyclamen  0 ‘Ca. P. solani’  
Dahlia  1,562,007 ‘Ca. P. mali’ 
Delphinium  618 16Sr I - aster yellows  
16Sr III - X-disease  
Dianthus   43,875  16SrXII  - “stolbur”  
‘Ca. P. australasiaticum’  
‘Ca. P. solani’  
Echinacea  108,8 42 ‘Ca.  P. solani’  
Euphorbia  15,293  16Sr II - peanut witches’ broom  
16Sr III - X-disease  
‘Ca. P. australasiaticum’  
‘Ca. P. australiense’  (strains not 
in New Zealand ) 
Ficus  349,883  ‘Ca. P. solani’  
Freesia  26,341,763 ‘Ca. P. solani’  
Gerbera  979,873  16Sr I - aster yellows  
16Sr II - peanut witches’ broom  
‘Ca. P. australasiaticum’  
Gladiolus  10,881,154  16Sr I - aster yellows  
Goodenia  0 16Sr II - peanut witches’ broom   
Ministry for Primary Industries  Amendments to the Import Health Standard 155.02.06: Importation of Nursery Stock  • 31 Host genus  Import quantity between 
2013 –2022 (units1) Target phytoplasma  to be 
managed2 
Gypsophila  4,345  16Sr II - peanut witches’ broom  
Hemerocallis  21,970  16Sr I - aster yellows  
Hibiscus  19,104  16Sr I - aster yellows  
16Sr V-D - “Flavescence dorée”  
‘Ca. P. solani’  
Hydrangea  2,061  ‘Ca. P. solani’  
Hypericum  40 ‘Ca. P. solani’  
Jasminum  60 16Sr II - peanut witches’ broom  
‘Ca. P. solani’  
Lavandula  12,326  ‘Ca. P. trifolii ’ 
‘Ca. P. solani’  
Lespedeza  3 16Sr I - aster yellows  
‘Ca. P. trifolii ’ 
Lilium  71,926,604  16Sr I - aster yellows  
‘Ca. P. mali’ 
‘Ca. P. solani’  
Limonium  86,053  16Sr II - peanut witches’ broom  
16SrV -Elm yellows  
Monarda  2,855  ‘Ca. P. solani’  
Narcissus  28,972,7 43 ‘Ca. P. australasiaticum’  
‘Ca. P. solani’  
Paeonia  349,122  16SrXII  - “stolbur”  
‘Ca. P. solani’  
Pelargonium  23,218  16Sr I - aster yellows  
‘Ca. P. australasiaticum’  
Petunia  40,895  16Sr I - aster yellows  
‘Ca. P. australasiaticum’  
Phlox  3,005  ‘Ca. P. australasiaticum’  
Phormium  100,979  ‘Ca. P. australiense’  (strains not 
in New Zealand ) 
Portulaca  2,616  16Sr I - aster yellows  
16SrXII  - “stolbur”  
‘Ca. P. solani’3 
Rhododendron  3,305  ‘Ca. P. trifolii ’ 
‘Ca. P. solani’  32 • Ministry for Primary Industries Amendments to the Import Health Standard 155.02.06: Importation of Nursery Stock   Host genus  Import quantity between 
2013 –2022 (units1) Target phytoplasma  to be 
managed2 
Rosa  7,453  16Sr I - aster yellows  
16SrXII  - “stolbur”  
‘Ca. P. australasiaticum’  
‘Ca. P. mali’ 
Salvia  5,039  ‘Ca. P. solani’  
Senecio  820 16Sr I - aster yellows  
Spiraea  10 16Sr III - X-disease  
Thymus  45 16Sr I - aster yellows  
‘Ca. P. mali’ 
‘Ca. P. solani’  
Veronica  334 16Sr I - aster yellows  
Zamia  1 16Sr II - peanut witches’ broom  
1 As reported in MPI’s QuanCargo  database . 
2 Considering the lowest taxonomic level possible  (‘Ca. P. species’, subgroup or group ). For example, if a 
phytoplasma does not have an assigned Candidatus  species  or subgroup , then the group will be used  (for 
example, 16Sr I - Aster yellows ).   
3 Identified through our Emerging Risks System .