Risk Management Proposal: 
Myrtaceae nursery stock from all countries.  
Specific measures for the Puccinia psidii complex  
(Guava rust and Myrtle rust). 
 
 
 
 
FOR PUBLIC CONSULTATION 
 
 
 
 
June 2011 
 
 
Plant & Plant Product Imports 
Import & Export Standards Directorate 
Ministry of Agriculture and Forestry 
Pastoral House 
25 The Terrace 
PO Box 2526 
Wellington 6011 
New Zealand 
 
 
Tel: +64 4 894 0170 
Fax: +64 4 894 0662 
Email: plantimports@maf.govt.nz
 
 
 
 
 
 
 
  
 TABLE OF CONTENTS 
 
 
Summary .................................................................................................................... 3 
Purpose ...................................................................................................................... 4 
Background ................................................................................................................ 4 
Objective ..................................................................................................................... 4 
Analysis of the P. psidii  biosecurity risk and management options ............................. 4 
1. Commodity ....................................................................................................... 4 
2. Pest Description ............................................................................................... 5 
2.1 Distribution of Puccinia psidii .................................................................... 5 
2.2 Host range ................................................................................................ 5 
3. MANAGEMENT OF RISK ................................................................................ 7 
3.1 Requirements of t he current Nursery Stock IHS standard ........................ 7 
3.2  Efficacy of the current IHS requi rements for managing the increased 
biosecurity risk ...................................................... Error! Bookmark not defined. 
3.3 Additional management options to consider ............................................. 8 
3.3.1 Pest Free Area ............................................ Error! Bookmark not defined. 
3.3.2  Fungicidal Treatment ................................. Error! Bookmark not defined. 
3.3.3  Additional conditions for Tissue Culture .................................................. 10 
4. PROPOSED AMENDMENTS TO THE STANDARD ..................................... 10 
REFERENCES ......................................................................................................... 13 
Appendix 1:   Myrtaceous gener a with species susceptible to Puccinia psidii ... 15 
 
MAF Biosecurity New Zealand 
Document for consultation June 2011 Page 2 of 15  
Summary 
MAF is proposing a number of changes to the import requirements for Myrtaceae nursery 
stock, under the import health standard (IHS)  155.02.06: Importation of Nursery Stock. The 
import requirements were reviewed because bo th the distribution and the host range of 
Puccinia psidii  has rapidly expanded in the past 15 months.   
 
The Guava rust fungus ( Puccinia psidii) has the potential to cause moderate to high 
economic, environmental and socio-cultural impacts in New Zealand.   
 
Puccinia psidii  is a native of Central and South America, but is also known to be present in 
the United States of America (F lorida, California, and Hawai’ i) and the Antilles (Cuba, 
Jamaica, and Trinidad and Tobago). Most recently, Uredo rangelii  (a species within the 
Puccinia psidii  complex, which has been given the co mmon name Myrtle rust) was identified 
in Australia in 2010. 
 
Since being identified in Aust ralia, the known host range of Puccinia psidii  has expanded 
considerably, from 21 to 35 Myrt aceae genera susceptible to in fection (Appendix 1). In New 
Zealand there are many iconic native species in  the Myrtaceae family, such as pohutukawa 
and rata ( Metrosideros sp.) and manuka ( Leptospermum  sp.), as well as the economically 
important Eucalyptus  and Feijoa ( Acca sellowiana ). 
 
This Risk Management Proposal provides jus tification for the proposed  amendments to the 
IHS to manage the risks posed by P. psidii.  It is proposed that the two schedules Agonis  and 
Acca sellowiana  (feijoa) be amalgamated under the Metrosideros  schedule, which will 
include all Myrtaceae genera currently eligible under Agonis, Acca sellowiana, Metrosideros  
and those covered under the Basic conditions. The schedules for Eugenia  and Eucalyptus will 
continue to be maintained as separate schedules, as these cover additional pests to Puccinia 
psidii.  
 
The post-entry quarantine (PEQ) requirements for whole plants and cuttings have been 
amended to require Level 3 facilities, to ensure that structural and operational measures are in 
place to prevent the escape of spores which ma y be present on infected foliage.  The PEQ 
period has also been extended to 6 months in the Metrosideros schedule. 
 
Tissue cultures are a lower risk pathway compar ed to whole plants and cuttings. However the 
current requirements for tissue culture in the IH S are not considered sufficient to manage the 
low risk of contamination with P. psidii  spores.  As P. psidi i favours young, actively growing 
tissue and high humidity, visible disease sympto ms are expected to be apparent within 12 
days of contamination, if the plantlets are actively growing an d maintained at temperatures 
between 15 to 23 ˚C.  If tissue cultures have spent a peri od of at least four weeks in the same 
media prior to export, they may be given bi osecurity cleara nce on arrival in New Zealand 
provided the phytosanitary certificat e is endorsed with the specif ic additional declaration. If 
this additional declaration is not endorsed on the phytosanitary certificate, the tissue cultures must be imported under a permit to import into a Level 3 PEQ tissue culture laboratory for a 
period of 4 weeks.  
 
 
MAF Biosecurity New Zealand 
Document for consultation June 2011 Page 3 of 15 Purpose 
The purpose of this document is to: 
 
 update the distribution of Puccinia psidii  and the known host species,  
 describe the likelihood that P. psidii  could be accidentally intr oduced into New Zealand on 
imported nursery stock, 
 recommend appropriate import meas ures to mitigate the risk of P. psidii in nursery stock, 
 Seek stakeholder feedback on the recommended management options and import 
requirements. 
 
Background 
 
There are currently specific measures for the rust fungus  Puccinia psidii under five schedules 
in the nursery stock IHS 155.02.06: Importation of Nursery Stock - Acca, Agonis, Eucalyptus, 
Eugenia and Metrosideros . In addition, there are currently 62  other Myrtaceae species that are 
eligible for import under the Basic Conditions with no specific measures for P. psidii . 
 
In April 2010, a member of the Guava rust complex ( Uredo rangelii ) was found on Myrtaceae 
species in Australia, expanding the known dist ribution and the range of host species the 
fungus infects. Since April 2010, MAF has suspe nded the issuance of pe rmits for Myrtaceae 
whole plants and cuttings from Australia, a nd is considering requests to import Myrtaceae 
whole plants and cuttings from other countri es on a case by case basis.  Myrtaceae tissue 
cultures are still eligible for import. 
 
The rust has an extremely broad host range, wh ich now includes plants from 35 genera of 
Myrtaceae.  It is now known to infect Lophomyrtus and Metrosideros species in Australia, 
both of which have species in New Zealand.  Shou ld it arrive here, it is  expected to spread 
rapidly and easily, affecting many of our iconic  native species. Due to its biology, eradication 
would be impossible, as was the experience in  Hawaii and Australia (Killgore & Heu, 2007; 
Loope & La Rosa, 2008; Eyles & Burnip 2010).   
 
The current IHS does not have provisions for regulation of P. psidii on many of these newly 
described hosts and the IHS needs to be update d to manage the risk for imported nursery 
stock from countries where P. psidii  is present.  
 
 
Objective 
The objective of the proposed measures is to effectively manage the biosecurity risk of 
Puccinia psidii  on imported nursery stock, in a way th at is consistent with New Zealand’ s 
domestic legislation and international obligations. 
 
Analysis of the P . psidii  biosecurity risk and management options 
1. Commodity 
Nursery stock of approved Myrtaceae plant species are listed on the MAF Plants Biosecurity 
Index , and may be imported into New Zealand as  nursery stock (whole plants, cuttings, and 
tissue culture) under the import health st andard (IHS) 155.02.06: Importation of Nursery 
MAF Biosecurity New Zealand 
Document for consultation June 2011 Page 4 of 15 Stock.  Since January 2005, all imports of My rtaceae whole plants and cuttings have been 
sourced from Australia, while tissue cultures of Myrtaceae have been sourced from Australia, 
India, and the United States of America.   
 
Myrtaceae nursery stock can be imported as whole plants or cuttings, or as tissue cultures, 
under the following five schedules, as well as 62 species under the Basic Conditions: 
 Acca sellowiana  (feijoa) 
 Agonis 
 Eucalyptus 
 Eugenia 
 Metrosideros 
 
2. Pest Description 
Puccinia psidii  is a rust fungus which infects plants ex clusively within the family Myrtaceae.  
The plant disease it causes is known as guava rust, eucalyptus rust, O’ hia rust or myrtle rust.  
Symptoms of the disease begin as small, gold en-yellow, powdery eruptions in a circular 
pattern on the leaf or stem. These spots expand and become necrotic, sp reading over the entire 
leaf, stem or shoot, and can affect floral buds  and fruit also.  Leaves and stems become 
deformed and growing tips can die back in  severe infections (Killgore & Heu, 2007).   
 
P. psidii spores can be spread by rain, insects (e.g. honeybees (Carnegie et al.  2010)), and 
wind.  Eradication is technically exceedingly difficult once established in the environment 
(NSW Department of Primary Industries, 2010).   
 
2.1 Distribution of Puccinia psidii   
Puccinia psidii  originates from Brazil and has si nce been found in Central and South 
America, and in the USA (Florida since 1977, California since at l east 2005, Hawaii since 
2005). It was recently found in Japan (Kawanishi et al. 2009).  It was reported in Taiwan 
(Wang, 1992) but has not been found sin ce 1992.   In all of these locations P. psidii  affects 
only species of the family Myrtaceae. 
 
P. psidii was discovered in New South Wales in Au stralia in April 2010, and subsequently in 
Queensland in December 2010.   
 
The fungus has been recorded to be pres ent in the following countries (CABI 2010): 
 Asia:  India, Taiwan, Japan  
 North America: Mexico, USA [Hawai’ i, Florida, California],  
 Central America:  Costa Rica, Cuba, Dominica, Do minican Republic, El Salvador, 
Guatemala, Jamaica, Puerto Rico, Trinidad and Tobago,  
 South America:  Argentina, Brazil, Amazonas, Espirito Santo, Pernambuco, Sao 
Paulo,  Colombia, Ecuador, Paraguay, Uruguay, Venezuela,  
 Oceania:  Australia (New South Wales, Queensland). 
 
2.2 Host range 
The P. psidii  complex is unique among rusts in that  it has an extremely wide host range 
within the Myrtaceae family.  Myrtaceae is a large family of plants, containing about 155 genera and over 3000 species, predominantly distributed in the southern hemisphere 
MAF Biosecurity New Zealand 
Document for consultation June 2011 Page 5 of 15 (Govaerts & Lucas, 2008; Wilson et al.  2001).  The arrival of P. psidii in Hawaii resulted in a 
rapid increase in known hosts. In  Australia, it is currently kno wn in 101 host species and 44 
genera (as at 13 June 2011; up from 69 sp ecies and 35 genera as  of 9 May 2011: NSW 
Department of Primary Industries, 2011). The tall y is expected to continue to expand as the 
rust spreads further in the Australian environment.   
 
The potential for new hosts in Australia is extremely high because it is the centre of 
Myrtaceae biodiversity, being home to 70 gene ra and 1646 species of native Myrtaceae, 
approximately half of the world’ s Myrtaceae species (Glen et al,  2007).  Therefore all 
Myrtaceae species are consider ed to be potential hosts. 
 
 
2.3 Summary of the biosecurity risk of P. psidii  on nursery stock  
The biosecurity risk of P. psidii on nursery stock imports to New Zealand has been assessed 
by MAF. 
 
Likelihood of Import into New Zealand 
In the pest risk assessment, the likelihood of P. psidii  entering New Zealand on Myrtaceae 
nursery stock was considered as moderate to high because: 
 Myrtaceae nursery stock is only routinely imported from countries where P. psidii is 
known to occur (i.e. Australia and USA); 
 At least one country, Hawaii, is thought to have received P. psidii via nursery stock 
importation;  
 Plant nurseries have in the pa st been unknown reservoirs of P. psidii ; 
 Plant nurseries in countries where P. psidii is established are likely to harbour P. psidii 
from time to time; 
 Whole plants or cuttings can be readily contaminated with P. psidii spores or 
intracellular mycelia prior to export;  
 Plants in vitro  (i.e. tissue culture) have a very low likelihood of being contaminated 
with P. psidii  spores or intracellular mycelia, but if they were they could enter New 
Zealand before symptoms became apparent; 
 Established infections would be easily detect ed at pre-export qua lity inspections, but 
early-stage infecti ons or individual P. psidii  spores could go undete cted at inspection; 
 Invisible P. psidii  contaminants on nursery stock ar e likely to be viable because 
transportation to New Zealand takes less than  a day and urediniospores are viable for 
up to 150 days. 
 
Likelihood of Finding Suitable Hosts in New Zealand 
In the pest risk assessment, the likelihood of P. psidii  being transferred to a new host in New 
Zealand was considered as high because: 
 Nursery stock are initially planted and placed next to other suitable hosts of P. psidii 
in nurseries; and there is also a wide availa bility of suitable host s outside the nursery; 
 Climatic conditions in nurseries are suita ble for the germination and infection by 
contaminating P. psidii  spores; 
 An actively growing nursery stock plant w ith a primary infection would produce new 
urediniospores within 12 days;  
 Urediniospores are easily dispersed by wind, rain, insects and by human assistance. 
 
Likelihood of Establishment in New Zealand 
In the pest risk assessment, the likelihood of P. psidii  being able to establish and spread in 
New Zealand was considered as high because: 
MAF Biosecurity New Zealand 
Document for consultation June 2011 Page 6 of 15  The New Zealand climate, particularly  in the North Island is suitable for P. psidii ; 
 There are many natural and modified habitats  in New Zealand, occurring in suitable 
climate areas, that coul d support the biology of P. psidii, including amenity plantings, 
plantations and New Zealand’ s native scrub and forests containing Myrtaceae species; 
 All Myrtaceae species are cons idered potential hosts of P. psidii because the 
experience of Hawaii and Australia demonstrat es that it affects hosts not previously 
predicted and it is likely to behave the same in NZ; 
 The experience of Australia and Hawaii de monstrates that, once established beyond a 
confined area, it is highly likely that eradication will be t echnically unfeasible; 
 P. psidii spores are easily spread and the disease ha s spread fast when it has arrived in 
other new locations (e.g. Australia; Hawaii); 
 The rate of spread of P. psidii is influenced by the sever ity of Myrtaceae infections 
and the consequent spore inoculum loading. 
 
Likelihood of Economic and Environmental Consequences in New Zealand 
In the pest risk assessment, if P. psidii  became established in New Zealand it would be 
considered to have moderate to high econom ic, environmental and socio-cultural impacts 
because: 
 It has the potential to cause direct mortality to New Zealand’ s native forest plant 
species in the family Myrtaceae, including pohutukawa, manuka, kanuka and rata ; 
 Myrtaceous species have a large influen ce on the structure, co mposition and function 
of New Zealand’ s indigenous ecosystems, so any change  in the fitness of these species 
could have cascading effect s through these ecosystems; 
 If manuka is moderately susceptible to P. psidii, the manuka honey industry could be 
negatively affected; 
 It could negatively affect the feijoa ( Feijoa sellowiana  or Acca sellowiana ) industry, 
with commercial production for domestic and export markets.  
 It could adversely impact the Eucalyptus timber, log, and pulp industries. 
 
3. MANAGEMENT OF RISK 
In order to provide a practical way of dea ling with a host range which is still undergoing 
expansion, the risk management measures for P. psidii on nursery stock will apply to all 
genera of Myrtaceae, as they are all re garded as potentially susceptible to P. psidii. 
 
 
3.1 Basic conditions of the Nursery Stock IHS standard 
There are currently 539 species of Myrtaceae elig ible for import into New Zealand as nursery 
stock. Of these, 62 species are only required to  meet the Basic Conditions, with no specific 
requirements for P. psidii.  The other 477 species were previo usly determined by MAF to be 
hosts or potential hosts of P. psidii, and specific measures for P. psidii are required under the 
schedule, either prior to export or while in PEQ.  
Myrtaceae plants can be imported as whole plants or cuttings, or as tissue cultures. Each type 
of nursery stock import has different risks associated with it. 
 
Whole plants or cuttings:   P. psidii attacks young actively growing leaves, shoots, floral buds 
and fruits.  Therefore, Myrtaceae whole plants or cuttings coul d conceivably be contaminated 
with P. psidii  spores through exposure to an infected source plant. Under the current import 
health standard, the Basic Conditions for w hole plants and cutti ngs (section 2.2.1) reduce 
some, but not all, of the risk of P. psidii  entry and establishment.  These are: 
 
MAF Biosecurity New Zealand 
Document for consultation June 2011 Page 7 of 15  Cleanliness: plants must be packaged in in ert/synthetic material and free from soil 
and other extraneous matter. 
 
 Pre-export phytosanitary inspection: prior to issuing a phytosanita ry certificate, the 
exporting National Plant Protection Organisation (NPPO) must inspect the nursery 
stock to ensure it is free from visually dete ctable regulated pests, and it conforms to 
New Zealand’ s import requirements. 
 
 Post-entry quarantine: the whole plants and cuttings must undergo Level 2 post-entry 
quarantine (PEQ) on arrival in New Zealand, during which time they undergo 
growing-season inspection by a MAF Biosecurity Inspector. 
 
Plants in vitro, i.e. tissue culture:  Assuming that aseptic lines of a tissue culture have been 
developed, and the tissue culture has been prep ared for export under sterile conditions, plants 
in vitro  have a very low likelihood of harbouring P. psidii. Under the current import health 
standard, the Basic Conditions for tissue culture (section 2.2.2) reduce so me, but not all, of 
the risk of P. psidii entry and establishment.  These conditions include: 
 
 Pre-export phytosanitary inspection: prior to issuing a phytosanita ry certificate, the 
exporting National Plant Protection Organisation (NPPO) must inspect the nursery 
stock to ensure it is free from visually dete ctable regulated pests, and it conforms to 
New Zealand’ s import requirements. 
 
 Cleanliness and packaging: tissue culture must  be packaged in pest proof and rigid 
containers, and must be free of visual c ontamination based on inspection on arrival 
by a Biosecurity Inspector  
 
3.2 Pest Freedom  
The International Standards fo r Phytosanitary Measures number 4: Requirements for the 
establishment of pest free areas, 1995 (ISPM No 4) describes the requirements for the establishment and use of pest free areas as a risk management option for meeting 
phytosanitary requirements for the import of plan ts.  A pest free area (PFA) is defined under 
the International Plant Protecti on Convention as “an area in wh ich a specific pest does not 
occur as demonstrated by scien tific evidence and in which, where appropriate, this condition 
is being officially maintained” .  ISPM 4 identifies three main aspects that must be considered 
in the establishment and subsequent maintenance of a PFA:  
 Systems to establish pest-free status 
 Phytosanitary measures to maintain pest-free status 
 Checks to verify pest-free status has been maintained. 
 
When sufficient information is available to  support a PFA declara tion, this phytosanitary 
measure is usually considered to provide a very  high level of protecti on.  The PFA could be a 
country, or an area within a country that is free of P. psidii (based on official survey data), or 
an area not likely to have P. psidii  introduced by natural disper sion, or does not have a 
climate that is likely to be suitable for P. psidii  (e.g. arid parts of Au stralia are considered 
unsuitable for P. psidii  (Booth & Javonivic, 2000)).  MAF w ould need to assess the evidence 
for PFA in accordance with ISPM No. 4. 
 
Two schedules ( Acca sellowiana  and Eugenia ) allow import of whole plants and cuttings 
from approved countries only.  In these cases th e phytosanitary certificate  must be endorsed 
with the additional declaration that “ Puccinia psidii  is not known to occur in (the country or 
MAF Biosecurity New Zealand 
Document for consultation June 2011 Page 8 of 15 state of origin)” . This type of declarati on is not the same as a ‘ pest-free place of production’  
declaration, or a ‘ pest-free area’  declaration certified by the exporting national plant 
protection organisation because it is not based on official pest surveys or inspections. 
Current approved countries include countries that have P. psidii  e.g. Australia, USA. 
 
The declaration only gives assurance that P. psidii  is not known to occur.  It is possible that it 
does occur, but has not yet been identified.  This  situation would have occurred for a period of 
time in Australia and Hawaii prior to P. psidii being identified and t hus it would not be the 
only risk management measure in use. 
 
3.3 Post Entry Quarantine  
The Level 2 PEQ facilities minimise the risk of establishment of pests that are likely to be 
transmitted by wind, water, insects or other vectors.  However, these conditions are 
considered inadequate to reduce the risk of P. psidii spore exposure to the environment to an 
acceptable level, because spores could escape Level 2 PEQ facilities. Windows and vents in 
Level 2 PEQ facilities are insect-proofed us ing mesh with a maximum aperture of 0.6 mm1, 
but this will not prevent the escape of P. psidii spores (urediniospores are ≤  0.027 mm and 
teliospores are ≤  0.048 mm2) (Katan & Katan, 1997; Frinking et al., 1987; Pfender et al.,  
2006; Chavarria et al.,  2009).  The hygiene procedures in  a Level 2 PEQ facility are not 
sufficient to stop transfer of spores onto personal clothing and subseque nt movement outside 
the facility.  
 
There are three major inadequacies of Level 2 PEQ for risk management of P. psidii: 
 The mesh on vents is not capable of preventing escape fungal spores and so P. psidii  
spores could spread into the environment via exit through the vent s (vent aperture is 
0.6mm; urediniospore size is much smaller, 0.027 mm). 
 The climate cannot be controlled, therefore th e facility would not be able to ensure 
conditions are optimal for observing P. psidii contamination (see section below on 
quarantine period for further details). 
 The operational procedures and record keepi ng are not sufficient to enable audits that 
would give assurances about th e management of Level 2 PEQ. 
 
Level 3 PEQ greenhouses have addi tional requirements for: reco rd keeping; maintenance of 
operational procedures which relate to quality system requirements; an optional provision for 
spore-proof ventilation systems; climate control.   All three of the Level 3 PEQ facilities in 
New Zealand are climate-controlled and under nega tive pressure.  At least one is fitted with 
air filters that are effective against microbe s (i.e. HEPA filtrati on). Level 3 PEQ would 
provide adequate risk management of P. psidii, assuming that spore-proof ventilation systems 
and adequate climate control are installed. 
 
P. psidii can have a life cycle of 10-25 days.  Therefore a weekly inspection or plant health 
check by PEQ operators, or representatives, is  necessary to identif y possible infections. 
Weekly plant inspections by the facility Operator is mandatory in Level 3 PEQ facilities and all records must be maintained  by the operator or representativ es.  Therefore, only Level 3 
PEQ provides an adequate plant inspection regime. 
 
                                                 
1 See MAF Biosecurity Authority Standard  PBC-NZ-TRA-PQCON Specification for the Registration of a Plant Quarantine 
or Containment Facility, and Operator; http://www.biosecurity.govt.nz/regs/trans/stds
2 Refer to http://www.issg.org/database/species /ecology.asp?si=1538&fr=1&sts=&lang=EN  and references therein. 
 
MAF Biosecurity New Zealand 
Document for consultation June 2011 Page 9 of 15 If plants are grown at 15-23 ˚C, high humidity, including overhead watering to promote leaf 
wetness, then disease caused by P. psidii can be expected to be vi sible after three to12 days, 
and probably within the three month PEQ period (summarised by Glen et al.  2007).   
 
But under other conditions, uredin iospores can remain viable beyond 3 months; Salustiano et 
al, 2008 reported urediniospores being viable  for 150 days (about 5 months) (Salustiano et al, 
2008; Suzuki & Silveira, 2003).  Also, it is no t known how long teliospores remain viable; 
teliospores are theoretically more persistent, but there is no data a bout teliospore survival 
time.  Therefore, a quarantine period th at extends beyond the maximum period of 
urediniospore viability is required.  Six months  is expected to be an adequate quarantine 
period. 
 
Temperature and humidity conditions that will encourage P. psidii contaminations to become 
visible can currently only be guaranteed in Level 3 PEQ facilities with climate control (they 
are currently not availa ble in any Level 2 PEQ facilities).  If plants are housed under optimal 
conditions3 for P. psidii  development, spores would lose vi ability within six months (Suzuki 
& Silveira, 2003).  Therefore the risk of P. psidii would be eliminated in PEQ, negating the 
need for mandatory testing.   
 
For a six month PEQ period, there should be four growing-season inspections by the MAF 
Biosecurity Inspector (BSI). The first inspection would be expected to occur at four weeks, 
after the consignment enters the PEQ facility, and then at three weekly intervals until the final 
inspection at five and a half to six months, prior to release.   
 
3.4 Additional conditions for Tissue Culture 
Tissue cultures are seen as a lower risk path way compared to whole plants and cuttings, 
however the current requirements for tissue cultur e in the IHS are not considered sufficient to 
manage the risk of contamination with P. psidii spores.  No contamination of P. psidii in 
tissue culture have been reported, however it is conceivable that contamination could occur, 
as it is known for other rust fungi  (Liefert & Cassells, 2001).  P. psidii is not documented as 
having latent intracellular infections, and so it is  expected that if a ti ssue culture plantlet was 
contaminated with P. psidii , symptoms would be visible with in two to four weeks if the 
cultures are maintained at 15-23 ˚C in high relative humidity (Glen et al.  2007). 
 
Therefore it is proposed that ti ssue cultures spend at least four weeks in the container they are 
imported in (either prior to export or in post entry quarantine), and must be maintained between 15-23˚ C for this period. If this occurs prior to export, the exporting National Plant 
Protection Organisation (NPPO) must certify this on the phytosanitary certificate. 
Alternatively, the exporting NPPO can endorse an additional declarat ion on the phytosanitary 
certificate that “ Puccinia psidii  is not known to occur in  the country of origin” . 
 
4. PROPOSED AMENDMENTS TO THE STANDARD 
 
It is proposed to rationalise the number of schedules for Myrtaceae species in the standard 
from five to three, by merging the Acca sellowiana  (feijoa) and Agonis schedules with the 
Metrosideros  schedule. The remaining three schedules would be: 
 
 Eucalyptus 
                                                 
3 Sub-optimal climate conditions may a llow extended survival of spores.  
MAF Biosecurity New Zealand 
Document for consultation June 2011 Page 10 of 15  Eugenia 
 Metrosideros 
 
In addition, the Myrtaceae specie s currently eligible for import under Basic Conditions will be 
added to the Metrosideros schedule. The proposed amendmen ts to these schedules are 
provided in the accompanying IHS document. 
 
Updated 
Schedule Genus Approved 
exporting countries Quarantine pests Phytosanitary measures 
Eucalyptus 
263 species 
  Eucalyptus  (263) All 
 Puccinia psidii; 
Endothia havanensis; 
Mycosphaerella 
parva   Whole plants or cuttings: 
- Level 3 PEQ, 6 
months. 
 
 Tissue culture: 
- Pre-export 
declarations 
 
OR 
- Level 2 PEQ, 4 
weeks. 
Eugenia 
31 species  Eugenia  (22)  
 Syzygium  (9) Australia, Austria, 
Belgium, Denmark, Finland, France, 
Germany, Greece, 
Hungary, Ireland, Israel, Italy, 
Luxembourg, 
Norway, The Netherlands, Portugal, 
Spain, Sweden, 
Switzerland, United 
Kingdom. 
 Puccinia psidii; Xylella fastidiosa   Whole plants or cuttings: 
- Level 2 PEQ for 
6 months with 
Pest-free area declaration  
 
OR Level  
- Level 3 PEQ, 6 
months. 
 
 Tissue cultures: 
- Pre-export 
declarations 
 
OR 
 Level 2 PEQ, 4 
weeks. 
Metrosideros 
245 species  Acca sellowiana 
Feijoa (1)  
 Actinodium  (1) 
 (8)  Agonis  
 Angophora  (3) 
Astartea  (2)  
 Austromyrtus  (1) 
 Backhousia  (2) 
 Baeckea  (10)  
 Beaufortia  (3) 
 Callistemon  (25) 
 
  
 (44)   Calothamnus  (9) 
 Calytrix  (9) 
 Darwinia  (9)
 Hypocalymma
 Kunzea  (15)  
 Leptospermum
 Lophomyrtus  (3) 
 Lophostemon  (1) 
 Luma  (1) Australia, Austria, Belgium, Denmark, Finland, France, 
Germany, Greece, 
Hungary, Ireland, Israel, Italy, 
Luxembourg, 
Norway, The Netherlands, Portugal, 
Spain, Sweden, 
Switzerland, United 
Kingdom, USA 
 Puccinia psidii   Whole plants or cuttings: 
- Level 2 PEQ for 
6 months with 
Pest-free area declaration  
 
OR Level  
- Level 3 PEQ, 6 
months. 
 
 Tissue cultures: 
- Pre-export 
declarations 
 
OR 
 Level 2 PEQ, 4 weeks. 
MAF Biosecurity New Zealand 
Document for consultation June 2011 Page 11 of 15  Melaleuca  (48) 
 
 
)  Metrosideros  (19)
 Micromyrtus  (1) 
 Myrciaria  (2) 
 Myrtus (6) 
 Pimenta  (1)
 Psidium  (7)  
 Thryptomene  (8
 Verticordia  (4) 
 
MAF Biosecurity New Zealand 
Document for consultation June 2011 Page 12 of 15 REFERENCES 
 
Alfenas, A.C., Maffia, L.A., Macabeu, A.J.  and Sartorio, R.C. 1993. Efficiency of 
triadimenol, oxycarboxin and diniconazole for rust ( Puccinia psidii ) control in coppice 
of Eucalyptus cloeziana  under field conditions.  Revista Arvore  17(2): 247-263.  
 
Carnegie, A.J., Lidbetter, J R., Walker, J ., Horwood, M.A., Tesoriero, L., Glen, M., and 
Priest, M.J. 2010. Uredo rangelii , a taxon in the guava rust complex, newly recorded on 
Myrtaceae in Australia.  Australasian Plant Pathology  39(5): 463-466.  
 
Chavarria, G., Santos, H.P., Fin, E., Sone go, O.R., Garrido, L.R. and Marodin, G.A.B. 2009. 
Aerial dispersion of Plasmopara viticola  spores in covered and conventional cultivation 
of grapevine.  Revista Brasileira de Fruticultura  31(3): 710-717.  
 
Ferrari, J.T., Nogueira, E.M. de C. and Santos, A.J.T. 1997.Control of rust ( Puccinia psidii ) in 
guava ( Psidium guajava ). Acta Horticulturae (452): 55-57.  
 
Frinking, H.D., Gorissen, A. and Verheul, M.J. 1987. Dissemination of spores in a 
glasshouse: pattern or chaos?  International journal of biometeorology  31(2): 147-156.  
 
Glen, M., Alfenas, A,C., Zauza, E.A.V., Wi ngfield, M.J. and Mohammed, C. 2007. Puccinia 
psidii: a threat to th e Australian environment and economy– a review.  Australasian Plant 
Pathology 36(1): 1-16. 
 
Govaerts, R. and Lucas, E. 2008. World Checklist of Myrtaceae.  Royal Botanic Gardens Kew.  
 
Katan, T., Shlevin, E. and Katan, J. 1997. Sporulation of Fusarium oxysporum  f.sp. 
lycopersici  on stem surfaces of tomato plants and aerial dissemination of inoculum.  
Phytopathology 87(7): 712-719.  
 
Kawanishi, T., Uematsu, S., Kakishima, M., Kagiwada, S., Hamamoto, H., Horie, H. and 
Namba, S. 2009. First report of rust disease on ohia and the causal fungus, Puccinia 
psidii, in Japan. Journal of General Plant Pathology  75(6): 428-431. 
 
Killgore, E.M., Heu, R.A. (updated March 2007) Ohia rust. Puccinia psidii Winter: Hawaii 
Department of Agriculture. 
 
Liefert, C. and Cassells, A.C. 2001. Microbial hazards in plant tissue and cell cultures. In 
Vitro Cellular & Developmental Biology . Plant 37: 133-138.  
 
Loope, L. and La Rosa, A.M. 2008. An Analysis of the Risk of Introduction of Additional 
Strains of the Rust Puccinia psidii  Winter (Ohia Rust) to  Hawaii. U.S Geological 
Survey Open-File Report 2008 -1008. 
 
Maclachlan, J. D. 1936. The pimento rust disease.  Journal of the Jamaica Agricultural 
Society  40: 277-281. 
 
MAF. 2009. Update of Tissue Culture Import Requirements. An internal MAF report. 
Ministry of Agriculture a nd Fisheries, New Zealand. 
     
MAF. 2010.  A Review of Australia's Myrtle Rust Response 2010 . A report for MAF 
Biosecurity New Zealand. 
 
MAF. 2011. Risk analysis of the Guava Rust complex (including Uredo rangelii  and Puccinia 
psidii ) on nursery stock. A report for MAF Biosecurity New Zealand. 
 
NSW Department of Primary Industries (2011) Situation Update 2 February 2011.  
http://www.dpi.nsw.gov.au/biosecurity/plant/myrtle-rust/update   
 
Pfender, W., Graw, R., Bradley, W., Carney, M.  and Maxwell, L. 2006. Use of a complex air 
pollution model to estimate dispersal and deposition of grass stem rust urediniospores at 
landscape scale.  Agricultural and Forest Meteorology  139(1/2): 138-153.  
 
Ruiz, R.A.R., Alfenas, A.C., Ferreira, F.A. and Zambolim, L. 1987. Protective and systemic 
fungicides for the control of eucalypt rust caused by Puccinia psidii. Revista Arvore 
11(1): 56-65.  
 
Ruiz, R.A.R., Alfenas, A.C. and Demuner, N.L.  1991. Efficiency of fungicides for the control 
of rust ( Puccinia psidii ) on guava (Psidium guajava ). Summa Phytopathologica  17(2): 
147-153.  
 
Suzuki, M.S. and Silveira, S.F. 2003. In vitro  germination of Puccinia psidii  urediniospores 
stored under different combinations of  relative humidity and temperature.  Summa 
Phytopathologica  29(2): 188-192.  
 
Wang, W. 1992. Survey of Eucalyptus diseases in Taiwan. Bulletin of the Taiwan Forestry 
Research Institute  7(2): 179-194.  
 
Wilson, P.G., O’ Brien, M.M., Gadek, P.A. and Quinn, C.J. 2001. 
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MAF Biosecurity New Zealand 
Document for consultation June 2011 Page 14 of 15     
Appendix 1:   Myrtaceous genera  with species susceptible to Puccinia 
psidii   
 
Prior to the Australian incursion, the known num ber of genera with species susceptible to P. 
psidii was 21; they are printed below in black italics with no highlighting. 
 
As at 2 February 2011, the 14 genera that are highlighted with yellow were new to the host 
list since the detection of U. rangelii in Australia in April 2010, bringing the total to 35.  As at 
13 June 2011, 10 additional genera (highlighted in green) were new to the host list since 2 
February 2011, bringing the tota l to 45 genera.  This represen ts a 114% increase of new host 
genera.  
 
Acca  (synonym Feijoa ) 
Acmena 
Acmenosperma 
Agonis 
Anetholea 
Astereomyrtus 
Austromyrtus 
Angophora 
Backhousia 
Callistemon 
Calothamnus 
Campomanesia  
Chamelaucium 
Choricarpia 
Corymbia 
Decaspermum  
Eucalyptus  
Eugenia 
Gossia 
Heteropyxis 
Kunzea 
Lenwebbia 
Leptospermum Lophomyrtus  
Marlierea 
Melaleuca 
Metrosideros 
Myrcia 
Myrcianthes 
Myrciaria 
Myrtus 
Pilidiostigma 
Pimenta 
Psidium 
Rhodamnia 
Rhodomyrtus 
Ristantia 
Stockwellia 
Syncarpia 
Syzygium 
Tristania 
Ugni 
Uromyrtus 
Waterhousea 
Xanthostemon 
 
 
MAF Biosecurity New Zealand 
Document for consultation June 2011 Page 15 of 15