Risk Management Proposal: 
Solanum lycopersicum  (tomato) seed for sowing, 
from all countries 
 
 
 
 
FOR PUBLIC CONSULTATION 
 
 
 
 
3 April 2012 
 
 
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
 
 
 
     
  
 
 1 
 
TABLE OF CONTENTS 
 
 
Purpose........................................................................................................................ ........................... 3  
Background..................................................................................................................... ........................ 3  
Object ive ...................................................................................................................... ........................... 4  
Analys is....................................................................................................................... ............................ 4  
1 Commodity...................................................................................................................... ..................... 4  
2 Risk assessment................................................................................................................ .................. 4  
2.1  Potato spind
le tuber viroid  (PSTVd).................................................................    5 
2.2 Tomato chlorotic dwarf viroid (TCDVd) ............................................................   6 
2.3 Tomato apical stunt viroid (TASVd) ..................................................................... 7 
2.4 Pepino mosaic virus (PepMV) .............................................................................. 8 
2.5 Pelargonium zonate spot virus (PZSV) ................................................................. 9 
3. Management of  risk............................................................................................................. ................ 9  
3.1 Seed preparation...................................................................................................... 12 
3.2 Pest free place of production................................................................................... 12 3.3 Pest free area ........................................................................................................... 12 3.4 Seed Testing............................................................................................................ 13 
Appendix 1: Proposed schedule for Solanum lycopersic
um, Import Health Standard 155.02.06: 
Importation of Seed for So wing ................................................................................................. ............ 14  
References............................................................................................................................................ 15  
 
 2 
  
Purpose 
The purpose of this document is to: 
 Provide a summary of the biosecurity risk analysis for imported  Solanum lycopersicum  
(tomato) seed for sowing, 
 Outline the technical justifi cation for the proposed phytosanitary measures to manage 
these risks, 
 Seek stakeholder feedback on the proposed changes to the import health standard.  
 
Background 
Tomato ( Solanum lycopersicum ) seed for sowing is eligible for import into New Zealand 
from all countries, under the import health standard (IHS) 155.02.05: Importation of Seed for 
Sowing . The import health standard sets out the basic requirements which must be met for 
imported seed, with specific schedules detaili ng additional requirements for plant genera with 
associated biosecurity risks in exporting countri es. Biosecurity risks include plant pests and 
diseases, such as nematodes, insects, inverteb rates, viruses, viroids, bacteria and fungi.  
 
Tom
ato seed can be imported into  New Zealand from all countries1 with the greatest volumes 
coming from the Netherlands, Australia, China a nd the USA. Tomato seed is a ‘Basic’ seed, 
meaning that it does not have a specific  schedule in the IHS and has no additional 
requirements other than the basic conditions. The seed must be clean and free of any 
additional plant material, weed seeds, or excess soil. It must be clearly labelled with the full 
botanical name (genus and species) and in a new, clean packet. The importer may provide a 
phytosanitary certificate or seed an alysis certificate, but this is  not essential, as there are no 
requirements for mandatory pre-export meas ures, phytosanitary inspections, pest free 
assurances, or treatments. The seed is then inspected by MAF on arrival in New Zealand for 
any visible contamination, and is given biosecu rity clearance on the ba sis of satisfactorily 
meeting these basic requirements. Seed compan ies, commercial growers, nurseries, and the 
general public may all import seed in this way.  MAF has completed a risk assessment for several viruses and viroids which are known to be transmitted in or on tomato seed. As visual inspection of seed at the border will not detect seeds infected with viruses and viroids, the current requirements do not specifically manage 
the biosecurity risks of these types of organism s. MAF has reviewed the current import system 
to assess whether the regulatory benefits of free and open trade in tomato seeds outweighs the 
biosecurity risks of the potential entry and esta blishment of these plant diseases. The technical 
justification for changi ng current requirements are pres ented in this document for public 
comment.  
                                                
 
1 Countries exporting tomato seeds to New Zealand: Argentina, Australia, Chile, China, Czech Republic, 
Denmark, France, Germany, Ghana, Guat emala, Hong Kong, Hungary, India, Israel, Italy, Japan, Korea-South, 
Malaysia, Mexico, Netherlands, Pakistan, Peru, Philippines, South Africa, Spain, Taiwan, Tanzania, Thailand, 
United Kingdom, USA, Vietnam, Zambia. 
 3 
Objective 
The objective of the review is to ensure that the biosecurity risks associated with imported 
tomato seed are effectively managed in a way that is consistent with both New Zealand’s 
domestic legislation and international obligations. 
 
Analysis 
This analysis is based on the Pest Risk Asse ssments for Tomato and Capsicum seed, prepared 
by the MAF Plants Risk Analysis Group http://www.biosecurity.govt.nz/regs/imports/ihs/risk  
The Risk Assessment document will be  available at the above website. 
 
1 Commodity 
Tomato ( Solanum lycopersicum ) is a member of the plant fa mily Solanaceae, which also 
includes the commercially im portant species potato (Solanum tuberosum ), chilli and bell 
peppers ( Capsicum spp.) , eggplant (Solanum melongena var. esculentum ), pepino ( Solanum 
muricatum ), and tamarillo ( Solanum betaceum ), as well as numerous ornamental and weed 
species introduced and natu ralised in New Zealand.  
 
Tomatoes are an important crop in New Zeal and: domestic sales of tomatoes in 2008/2010 
were worth $113 million, and exports worth $14 million (Plant and Food Research, 2010).   
 
Tom
ato seeds are classified by MAF as a ‘Basic ’ species, and are elig ible for import under the 
basic conditions of the IHS 155.02.05: Importa tion of Seed for Sowing (section 2.2.2). The 
seed must be clean and free of any additional pl ant material, weed seeds, or excess soil and 
clearly labelled with the full bot anical name (genus and species) in a new, clean packet. There 
is currently no requirement for mandatory pre-export measures, such as phytosanitary 
inspections and certification, pest free assurances, or treatments. 
 
2 Risk assessment 
MAF have reviewed the biosecurity risks asso ciated with tomatoes and identified five 
regulated viruses and viroids which are transmitted in seeds. One other viroid which can infect 
tomatoes was identified, but as there is no definitive evidence for seed-to-seedling 
transmission it has not been considered furthe r in this risk management proposal (RMP). 
A summary of the main points of the risk analysis for each of the following viruses and viroids 
are included in this document and risk management measures proposed: 
 
1. Potato spindle tuber viroid (PSTVd);  
2. Tomato chlorotic dwarf viroid (TCDVd);  
3. Tomato apical stunt viroid (TASVd); 
4. Pepino mosaic virus  (PepMV)  and  
5. Pelargonium zonate spot virus (PZSV). 
 Viruses and viroids are highly infect ious organisms which replicate inside plant cells and 
cause various types of plant dis eases. Common symptoms include ringspots, mosaic pattern 
development, fruit marbling, leaf yellowing and distortion, and deformed growth. The diseases 
do not typically result in plant deat h, but often result in yield losses.  
 4 
 
The percentage of infected seeds which grow s into infected plants  is called the seed 
transm
ission rate, and this rate depends on the st rain of the virus/viroi d, the variety of the host 
plant, and environmental conditions. Once an infect ed plant is established, the virus/viroid can 
be readily spread by mechanical means to other tomato plants through plant to plant contact, 
handling by people, contact with contaminated  clothing, through graftin g, or through the use 
of contaminated tools or equipment. Some viruses and viroids can also be transmitted by 
insects feeding on plant sap, or through pollen transfer. 
 
As tom
atoes are annual crops the diseases wi ll not persist beyond a single growing season 
unless infected seeds are saved and replanted, or infected self-sown tomato plants perpetuate 
the disease from year to year. In commercial pr oduction, seeds are not save d from year to year, 
but imported each season. Plants are destroyed at  the end of the season; in glasshouses, the 
growing areas are disinfected between crops; in  outdoor grown commerci al crops, fields are 
replanted in rotation with other crops. These practices help to eliminate the virus/viroid each season. In home gardens, some gardeners save seed for replanting th e following year, and 
there is also the opportunity for self-sown plants from dropped fruit with seed overwintering in 
the soil. This creates the potential for the diseases to reappear the following year.  
Most of the viruses and viroids can infect m
ore than one host plant species meaning the 
diseases could spread from an infected tomato plant to a different host plant by the same mechanisms as tomato-to-tomato spread. The likelihood of spread between different host species is minimised in commercial cropping situations wher e workers handle only tomato 
plants, but is possible in situ ations where several different  hosts are growing in close 
proximity. In home garden situations, it woul d be quite common for several different host 
species to be grown in close proximity, and th ere could be many opportun ities for spread via 
handling or contaminated tools. If  the diseases are spread to a pe rennial host species, there is a 
potential for establishment in the environment w ith provision for a reservoir of infected plants 
which can infect other hosts ove r subsequent years. Some viru ses and viroids can also be 
spread by insects, such as aphids and bumblebees.   
2.1  Potato spindle tuber viroid  (PSTVd) 
Potato spindle tuber viroid  (PSTVd) is primarily a pathoge n of potato, however it naturally 
infects other solanaceous crops including tomato, aubergine ( Solanum melongena), pepino 
(Solanum muricatum ), and capsicum ( Capsicum annuum)  (Lebas et al., 2005). The potential 
economic impacts if PSTVd was to establish in New Zealand are assessed to be low to 
moderate.  PSTVd is transmitted by seed and pollen of infected tomato and potato plants (Singh, 1970; Lebas et al., 2005). In tomato seeds, PSTVd occurs w ithin the seed tissues rather than as a 
contaminant on the seed surface (Matsushita et al.,  2011). The seed transmission
2 rate varies 
from 2 to 31% in tomato (Singh, 1970). If seed tr ansmission occurs, it is very likely that the 
disease will spread throughout the crop, as the viroid is highly contagious and readily transmitted by contaminated tools, workers’ hands and clothing.   PSTVd has been detected on a few occasions  in New Zealand in tomato and capsicum 
glasshouse plants, but was eradicated each time (Ward et al., 2010). It was also found in Cape 
                                                
 
2 The rate at which infected seeds germ inate and lead to an infected plant. 
 5 
gooseberry and tobacco plants in Christc hurch and Auckland respectively in 2009, and 
infected plants and seeds from
 the supplier we re destroyed (MAF response close out report, 
2009). 
 PSTVd is found in Afghanistan, Belarus, Canada, Chile, China, Costa Rica, Czech Republic, Egypt, Germany, India, Iran, Italy, Netherlands , Nigeria, Peru, Poland, Russian Federation, 
Slovenia, Turkey, Ukraine, United Kingdom, US A, and Venezuela (CPC, 2010). It has also 
been reported from Greece (Malandraki et al., 2010), and Belgium (Verhoeven et al ., 2007). 
PSTVd has been reco
rded as occa sionally having symptomless infections in tomatoes (Agrios, 
2005), though in other cases severe symptoms have been reported (Ling and Sfetcu, 2010; and Kryczynski et al., 1995).  
 There is a possibility that PSTVd could sp read from tomatoes to potatoes by aphids ( Myzus 
persicae ), if the tomatoes are co-infected with Potato leafroll virus  (PLRV; Querci et al., 
1997; Syller et al., 1997). Both the aphid and the virus ar e present in New Zealand (Van Toor 
& Teulon, 2006), however tomato is a poor host of the virus (Syller et al., 1997; Syller and 
Marczewski, 2001). PSTVd symptoms on potato t ubers vary from severe to mild and 
symptomless. The tubers can be elongated, with  tapering ends (Agrios,  2005); they can have 
more numerous and more conspicuous eyes, and can also be cracked. There is uncertainty 
about the impact of PSTVd on potato crops under current agricultural conditions.   
 
2.2 Tomato chlorotic dwarf viroid (TCDVd) 
Tomato chlorotic dwarf viroid (TCDVd) is seed-transmitted in tomato (Singh & Dilworth, 
2009), and is found in India, Israel, Mexico, Slovenia, Portugal, Finland and the Czech 
Republic. It was intercepted in the Nether lands and the United Kingdom in 2009, and was 
eradicated from Japan and Canada in 2010/2011.   There are conflicting reports about whether TCDVd  occurs as a contaminant on the surface of 
the seed coat (Matsushita et al ., 2011) or whether it is found sy stemically within the seed 
tissues (Singh & Dilworth, 2009). TCDVd has been detected in at least one commercial seed 
lot (Candresse et al., 2010). However, as there are no reports  of symptomless expression of the 
disease in tomatoes, there is a low likelihood that seed from inf ected plants would be cleaned 
and sold commercially.   The rate of seed-to-seedling transmission is  highly variable, and ranges from 0 to 80%. 
TCDVd is easily transmitted and spread mechanically, e.g. by contact with contaminated tools 
and fingers during routine crop management such  as the removing of lateral shoots (Singh & 
Dilworth, 2009; Matsushita et al., 2009).  TCDVd can also be transmitted via bumblebees and via vegetative propagation such as the use of cuttings.    Commercially grown tomato plants infected wi th TCDVd have chlorotic leaves, reduced leaf 
size, smaller and sometimes deformed fruit, veinal and petiolar necrosis, and overall 
bunchiness and dwarfing (Figure 3. Sing et al. , 1999; Singh & Dilworth 2009; Matsushita et 
al., 2008). TCDVd infection in tomato crops c ould reduce the production of saleable product 
as has been recorded from other countries, in cluding Japan, France and Canada. In France, the 
prevalence of infected plants within a gr eenhouse was variable but reached up to 25% 
(Candresse et al., 2010).  Some of the affected plants continued to produce saleable fruit, so 
the production losses overall we re less than 25%. The potential economic impacts if TCDVd 
was to enter and establish in New Zealand ar e therefore assessed as low to moderate. 
 6 
 
 
       
 
 
 
  
 
 
 
  
 
  
 
 
Figure 3. Greenhouse tomato plants infected with Tomato chlorotic dwarf viroid . 
 
From  http://www.agf.gov.bc.ca/cropprot/tcdvd.htm  
 
Experim
entally, TCDVd has been demonstrated  to be spread between tomato plants by 
bumblebees in a glasshouse. This is thought to occur by mechanical means as the bumblebee 
grasps the anthers with their mandibles (Matsuura et al., 2010), rather than by pollen spread. It 
is not known whether bumblebees could spread TCDVd between different plant hosts by this 
mechanism, if they were to visit flowers of different hosts.  
The most predominant natural hosts are recorded as tomato and Petunia hybrida  (petunia). 
Both of these plants are annuals. Therefore unless the viroid is spread to  perennial hosts, or the 
infected plant produces contaminated seeds that  germinate the following season, the viroid is 
unlikely to establish in New Zealand beyond one  growing season. Perennial host plants which 
are found in New Zealand include Vinca major, Brugmansia sanguinea, and Pittosporum 
tobira . 
 
2.3 Tomato apical stunt viroid (TASVd) 
Tomato apical stunt viroid  (TASVd) is seed transmitted in tomato and has a wide geographical 
distribution in Europe, Middle East, Africa, SE Asia, and the USA (EPPO 2010). TASVd has 
been recorded in commercial seed lots, having been intercepted once in tomato seed being 
exported from the USA to Israel (EPPO 2010). Symptoms are very similar to those of other viroids in tomatoes, in cluding stunting, apical 
proliferation, apical leaf narrowing and yello wing, leaf crinkling, tissue brittleness, and 
necrosis. The fruits can be considerably reduc ed in size and have pale red discolouration 
(Antignus et al., 2002 and 2007). 
 TASVd can be transmitted via seed, by bumble bees, and has been tran smitted mechanically 
under experimental conditions using sap from inf ected plants, and by workers’ infested hands 
and tools (Antignus et al., 2007). To persist in the outdoors environment for longer than one 
season, the viroid would need to be spr ead to a perennial host species (such as Solanum 
jasminoides, Brugmansia sp, and Cestrum  sp. Verhoeven et al ., 2008 & 2010). The likelihood 
of this occuring is highly uncertain, and depe nds on the proximity of tomato crops to these 
weedy shrubs. It is not currently known whethe r bumblebees are able to transmit the viroid 
between different plant species.  
 7 
Hom
e gardeners who save seed and distribut e it to other growers around the country may 
provide a pathway for infected seeds to travel  long distances within  New Zealand. However, 
as tomato are the only commercial crop species  affected by this vi roid, the impacts of 
establishment in the environment will be much lower than for the other viruses and viroids. 
The economic impact for the establishment of TASVd is a ssessed as low to moderate. 
 
2.4 Pepino mosaic virus (PepMV)  
Pepino mosaic virus  (PepMV) is highly infectious, and can be spread by direct plant-to-plant 
contact and propagati on by grafting. PepMV infects mainly solanaceous plants, including 
tomato, potato and tobacco. It was reported on greenhouse tomatoes ( Solanum lycopersicum ) 
in the Netherlands and United Kingdom in 1999, and has subsequently been detected in 
several other European countries and North America. PepMV has been detected by other 
countries in tomato seed consignments every ye ar since at least 2007 (EPPO, various dates).   
 
PepMV is located in the seed coat in toma to (Ling, 2008), and can be transmitted to the 
growing seedling at a low rate (estimated as 0.026% by Hanssen et al., 2010). The rate of 
transmission depends on the time of seed harv est, the variety, and th e seed extraction and 
cleaning methods applied (Cordoba-Selles et al., 2007; Ling, 2008; Hanssen et al ., 2010; 
Hanssen & Thomma, 2010). Poorly cleaned fresh seeds have highe r rates of seed transmission 
compared to well cleaned, mature seeds.  
In the presence of the soil fungus Olpidium virulentus, PepM
V can also be transmitted in 
hydroponic systems via the irrigatio n water/nutrient solution, l eading to the infection of 
healthy tomato plants  (Alfaro-Fernandez et al., 2010). Bumblebees can al so transmit the virus 
between tomato plants, and between tomato a nd weed species such as nightshade (Stobbs et 
al., 2009). If PepMV is transmitted to a perennial host species through bumblebees or 
mechanical transmission, then those plants could become a potentia l reservoir in the 
environment and a potential source for re-infection in the following year. 
 Symptoms in tomato plants are variable, and can range from symptomless plants to single 
yellow spots between veins, yellow mosaic, gree n mosaic (Figure 1), l eaf bubbling, other leaf 
malformations, and fruit marbling (Figure 2).  
 
 
 
Figure 1. Leaf symptoms on tomato plants  
infected with Pepino mosaic virus  Figure 2. Fruit symptoms on tomato plant infected with  Pepino mosaic virus. 
 8 
do you have a source for these photos?  
 
The potential economic impacts if PepMV was to  enter and establish in New Zealand have 
been assessed as low to high. PepMV is highl y likely to establish and spread throughout a 
tomato crop if exposure occurs because it is highly  contagious and easily spread between 
tomato plants.  Bumblebees can transmit this virus between tomato plants.  The economic impacts of PepMV vary depending on factors su ch as the PepMV strain, tomato cultivar, 
environmental factors, and co-infection with O. virulentus .  These consequences could arise 
every year simply through the importation and growing of infected seed. 
 
2.5 Pelargonium zonate spot virus (PZSV) 
Pelargonium zonate spot virus (PZSV) has been reported as a severe disease of tomatoes, 
resulting in plant death (Vovlas et al., 1989). It has been recorded from Italy, Spain, France, 
the USA (California), Israel (Lapidot et al., 2010) and Australia (Luo et al., 2010).  
 
The virus is seed tr
ansmitted in tomato plants . Symptomless expression in tomato plants has 
not been reported, which reduces the likelihood that seed from infected plants would be 
cleaned and sold commercially. Seed from PZSV infected tomato plants gives rise to infected seedlings with a seed-to-seedling transmission rate of 11-29% (Lapidot et al., 2010).  Other 
host plants of PZSV that occur in New Zealand include Pelargonium zonale (common 
geranium) and the weeds Cakile maritima, Capsella bursa-pastoris,  Chrysanthemum segetum,  
Sonchus oleraceus, globe artichoke ( Cynara scolymus), and kiwifruit ( Actinida deliciosa ). 
There is no known insect vector for this virus, and thus mechanical transmission is considered 
the mechanism for spread in the environment. 
 Economic impacts if PZSV was to enter New Zealand and spread through  the tomato crop are 
expected to range from low to moderate, depe nding on the severity of symptoms. Symptoms 
include reduced fruit size and/or  quality, and/or reduced  yield due to poor pl ant health or even 
plant death. If PZSV established in the wider en vironment, in perennial  crops or ornamental 
species which act as a reservoir for the pathogen, longer-term economic impacts could arise. 
There is uncertainty about the impacts on kiwifr uit orchards if the vi rus were to become 
established in New Zealand.  
3. Management of risk 
MAF’s current requirements allow tomato seed to be imported under ‘Basic Conditions’ (section 2.2.2). These conditions do not specifically manage the bi osecurity risk of viruses and 
viroids in imported tomato seeds. Each of th e viruses and viroids which have been assessed 
have the potential to cause unwanted impact s should they enter New Zealand. The impacts 
range in severity from low to moderate to  high, depending on where the crops are grown. 
Should the pathogens establish in the environment,  there is the potential for unwanted harm to 
other cropping industries.  A summary of the risks assessments for each of th e viruses/viroids assessed for tomato seed is 
included in table 1.   It is essential for import requirements to st rike a balance between decreasing the likelihood 
that these viroids and viruses will enter Ne w Zealand, while maintaining access to tomato 
seed. Recognising that it is not possible to  completely eliminate risk, the management 
 9 
 10measures selected are considered to deliver th e highest benefit at the lowest regulatory and 
compliance cost. 
 The following principles have been used  to select the management measures: 
 That the measures are risk-based and no more than necessary to achieve the outcomes sought; 
 That the regulatory benefits  must outweigh the costs; 
 That measures are internationally comparable, and will not disadvantage New Zealanders; and 
 That the risk management measure(s) deliver  the highest level of net benefit for the 
lowest cost. 
 A new schedule for Solanum lycopersicum  in the Seed for Sowing standard is proposed 
(included in section 5, pages 12- 13). The management options are discussed in further detail 
below.  .  
Table 1.  Summary of risk assessment of seed-transmitted viruses and viroids associated with toma to seeds imported into New Zea land 
Risk 
Organism Seed-to-
seedling 
transmission 
rate Major hosts Perennial hosts Mechanisms for spread in 
the environment Economic 
Impacts Symptomless in 
tomatoes? Effective Risk 
Management 
measures 
TCDVd Low to High  
(0 -80%) Annuals: tomato, Petunia hybrida 
(symptomless), 
Verbena x hybrida  Vinca major  
(symptomless); 
Pittosporum tobira; 
Brugmansia sanguinea: 
Calibrachoa  spp. Tomato seed-to-seedling, 
mechanical touch, 
bumblebees (experimental). 
Likelihood of establishment in the environment: Low to 
Moderate. Low to 
Moderate No reports of symptomless 
expression 
Good seed preparation 
may minimise 
infection rates. 
Growing season 
inspection of parent 
plants or testing. 
PSTVd 
 
 
 Low to 
Moderate (2-
31%) Annuals: tomato, 
Potato ( Solanum 
tuberosum ) Brugmansia sp. and Solanum jasminoides 
(both symptomless) ; 
Persea americana 
(avocado); Solanum 
muricatum  (pepino); 
Ipomoea batatas . Tomato seed-to-seedling, bumblebees (pollen), 
mechanical touch, aphids if co-infected with a virus. 
Likelihood of establishment 
in the environment: Low to Moderate. Low to 
Moderate Can be symptomless 
Pest Free Area 
or testing 
TASVd High (80%) Annuals: tomato Brugmansia sp., Solanum jasminoides, 
Cestrum sp. Tomato seed-to-seedling, 
bumblebees (tomato-to-
tomato), mechanical touch (experimental). 
Likelihood of establishment 
in environment: Low to 
Moderate. Low to Moderate No reports of symptomless 
expression 
Growing season 
inspection of parent 
plants. 
 
PepMV Low (0.026 <2%) Annuals: tomato, basil ( Ocimum 
basilicum ), 
potato ( Solanum 
tuberosum ). Solanum muricatum  
(pepino); Tomato seed-to-seedling, bumblebees, Mechanical touch. 
Likelihood of establishment 
in environment: Moderate. Low to High Can be 
symptomless 
Good seed preparation 
minimises infection 
rates. 
 
Pest Free Area 
or testing 
PZSV Moderate (11-
29%) Annuals: tomato Pelargonium zonale  
(geranium); Cynara 
scolymus (globe 
artichoke); Actinidia 
(kiwifruit) Tomato seed-to-seedling, Pollen, Mechanical touch. 
Likelihood of establishment in environment: Low to 
Moderate. Low to Moderate 
(with uncertainty) No reports of 
symptomless 
expression 
Growing season 
inspection of parent 
plants  
or testing 
 11 
 
 
3.1 Seed preparation 
It is unlikely that symptomatic plants woul d be used in the production of high value 
commercial seed. However PSTVd and Pe pMV are known to produce symptomless 
infections, so infected seeds can be u nknowingly included in commercial seed lots. 
 PepMV is known to reside in the seed coat. Seed cleaning or disi nfection methods which 
completely remove traces of tomato flesh reduce the incidence of seed-to-seedling transmission of the virus from 2% to 0.0026% (Ling, 2008). Therefore it is proposed that a 
requirement for seed to be commercially prepar ed to industry standard s, utilising techniques 
such as acid extraction of seed, will reduce transmission rates of  PepMV . However, t his 
requirement will not reduce transmission of viruses/viroids which are located within seed tissues rather than on the seed surface, a nd other management measures will be needed. 
  
3.2 Pest free place of production 
A Pest free place of production (PFPP) is defined as a “pl ace of production in which a 
specific pest does not occur as demonstrated  by scientific evidence and in which, where 
appropriate, this condition is being officially maintained for a defined period” [ISMP No. 10, 
1999].   PFPP’s are established via surveys and/or grow ing season inspections to establish that no 
symptoms of the virus/viroids are observed on the plants at the place of production during 
their cycle of growth and seed production. The ph ytosanitary measure is usually considered to 
provide a very high level of protection for vi ruses/viroids which have readily observable 
symptoms. This measure will be suitable for the detection of PZSV and the viroid TCDVd. 
The viroid TASVd will also be observed during growing season inspections, therefore no specific measures are proposed for this viroid.  However as PSTVd and PepMV are known to some times have symptomless infections, this 
measure is not considered sufficient for these organisms.  
 
3.3 Pest free area  
A Pest Free Area (PFA) is defined as “an area in which a specific pe st does not occur as 
demonstrated by scientific evidence and in wh ich, where appropriate, th is condition is being 
officially maintained”. ISPM No. 4 describes the requirements for the establishment and use 
of PFA endorsement on the phytosanitary certif icate as a risk management option for the 
import of plants.  The PFA could be a country, or an area within a country, that is free of the virus or viroid (based on official  survey data), or an area not li kely to have a virus or viroid 
introduced by natural dispersion, or does not have a climate that is likely to be suitable for the 
particular virus or viroid. Wh en sufficient information is  available to support a PFA 
declaration, this phytosanitary measure is usually  considered to provide a very high level of 
protection.    It is recommended that MAF re quires Pest Free Area declara tions for viruses and viroids 
which have occasional symptomless infections.     
3.4 Seed Testing 
Where Pest Free Area or Pest Free Place of Produc tion endorsements are not available, a third 
option for seed testing is proposed. Seed tes ting, using appropriate methods can provide a 
high level of assurance that seeds are not  infected with viruses or viroids.  
 
MAF proposes that a 4600 seed sample is collected, which has been representatively sampled, and sent for official testing. This  size sample gives a 99% assuran ce that an infection rate of 1 
seed in 1000 virus/viroid-free s eeds (0.1%) will be detected. This  size sample can detect much 
lower levels of infection in a seed lo t, but at a lower confidence interval. 
  
 13    
Appendix 1: Proposed schedule for Solanum lycopersicum , Import 
Health Standard 155.02.06: Importation of Seed for Sowing 
 
Solanum lycopersicum 
 
Note:  These entry conditions only apply to speci es in the Plants Biosecurity Index listed 
under Import Specifications for Seed as “see 155.02.05 under Solanum lycopersicum ”. 
 
 GENERAL CONDITIONS:
 
 
Countries: All 
 
Quarantine Pests:  Potato spindle tuber viroid (PSTVd) ; Tomato chlorotic dwarf viroid 
(TCDVd); Tomato apical stunt vi roid (TASVd); Pepino mosaic 
virus(PepMV) ; Pelargonium zonate spot virus (PZSV) . 
 
 
Entry Conditions: Basic; PLUS 
 
 
Phytosanitary Certificate Requirements: 
Before a phytosanitary certificate is issued, the NPPO of the exporting country m
ust be 
satisfied that the following activities required by MAF have been undertaken.  
 
The Solanum lycopersicum  seeds for sowing have been: 
- Prepared to industry standards with thorough cleaning to remove  all traces of flesh from 
the seeds. 
 
Phytosanitary Certificate Additional Declarations: 
If satisfied that the pre-shipment activities have been undertaken, the exporting country NPPO 
must provide one of the following additional de clarations to the phytos anitary certificate: 
 
For Potato spindle tuber viroid  (PSTVd), Pepino mosaic virus (PepMV),  Tomato chlorotic 
dwarf viroid (TCDVd)  and Pelargonium zonate spot virus (PZSV): 
 
“The Solanum lycopersicum  seeds in this consignment have been: 
 
- sourced from a “Pest Free area” and/or  a “Pest Free place of production”, free from  
Potato spindle tuber viroid  (PSTVd), Pepino mosaic virus (PepMV), Tomato chlorotic 
dwarf viroid (TCDVd)  and Pelargonium zonate spot virus (PZSV), 
 OR 
 
- subjected to official testi ng using a 4600 seed sample and have been found to be free 
from from  Potato spindle tuber viroid (PSTVd), Pepino mosaic virus (PepMV),  
Tomato chlorotic dwarf viroid (TCDVd)  and Pelargonium zonate spot virus (PZSV)’. 
 
 
  
 14    
References 
 
Agrios, G. 2005. Plant Pathology, Fifth Ed ition. Elsevier Academic Press, 922pp 
 Alfaro-Fernandez, A., M. Cordoba-Selles, J.A. Herrera-Vasquez, MdC. Cebrian, and C. 
Jorda. 2010. Transmission of Pepino mosaic virus  by the fungal vector Olpidium 
virulentus. Journal of Phytopathology  158(4): 217-226. 
 
Antignus, Y., O. Lachman, M. Pearlsm
an, R.  Gofman and M. Bar-Joseph. 2002. A new 
disease of greenhouse tomatoes in Isr ael caused by a dist inct strain of Tomato apical 
stunt viroid (TASVd). Phytoparasitica 30(5): 502-510 
 Antignus, Y., O. Lachman and M. Pearlsman. 2007. Spread of Tomato apical stunt viroid 
(TASVd) in greenhouse tomato crops is asso ciated with seed transmission and bumble 
bee activity. Plant Disease  91: 47-50 
 CABI/EPPO. 2008. Tomato apical stunt viroid. Distribution Maps of Plant Diseases. Map 
number 1029 Edition 1 Issued April 2008. 
 CPC. 2010. Crop Protection Compe ndium. CAB International  
 
Candresse, T., A. Marais, X. Tassus, P. Suha rd, I. Renaudin, A. Leguay, F. Poliakoff and D. 
Blancard. 2010. First report of Tomato chlorotic d
warf viroid in tomato in France.  
Plant Disease  94(5): 633.  
 Córdoba-Selles, M. C., A. Garcia-Randez, A.  Alfaro-Fernandez and C. Jorda-Gutierrez. 2007. 
Seed transmission of Pepino mosaic virus  and efficacy of tomato seed disinfection 
treatments.  Plant Disease  91(10): 1250-1254.  
 EPPO. 2010. EPPO Reporting Service Paris 1/4/2010, 2010/088  EPPO. 2011. Alert List: Tomato apical stun t pospiviroid. Updated 26 August 2011. Available 
at: http://www.eppo.org/QUARANTINE/Al ert_List/viruses/TASVD0.ht
 m 
 Hanssen, I. M., R. Mumford, D.R.  Blystad, I. Cortez, B. HasiowJaroszewska, D. Hristova, I. 
Pagan, A.M. Pereira, A M; J. Peters, et al.  2010. Seed transmission of Pepino mosaic 
virus  in tomato.  European Journal of Plant Pathology  126(2): 145-152.  
 Hanssen, I. M. and B. P. H. J. Thomma. 2010. Pepino mosaic virus : a successful pathogen 
that rapidly evolved from emerging to endemic in tomato crops.  Molecular Plant 
Pathology 11(2): 179-189.  
 Kryczynski, S., A. Stawiszynska, and T.A.  Abuhliga. 1995. The reaction of field-grown 
tomato cultivars to infection with potato spindle tuber viroid (PSTV). Phytopathologia 
Polonica  22: 85-91. 
 Lapidot, M., D. Guenoune-Gel bart, D. Leibman, V. Hold engreber, M. Davidovitz, Z. 
Machbash, S. Klieman-Shoval, S. Cohen, and A. Gal-On. 2010. Pelargonium zonate 
spot virus is transmitted vertically via seed and pollen in tomato. Phytopathology 100: 
798-804. 
 15    
 
Lebas, B. S. M., G.R.G. Clover, F.M
. Ochoa -Corona, D.R. Elliott, Z. Tang, and B.J.R. 
Alexander. 2005. Distribution of Potato spindle tuber viroid in New Zealand 
glasshouse crops of capsicum and tomato. Australasian Plant Pathology 34: 129-133. 
 Ling, K. S. 2008. Pepino mosaic virus  on tomato seed: virus location and mechanical 
transmission. Plant Disease  92(12): 1701-1705.  
 Ling, K.S. and D. Sfetcu. 2010. First report of natural infection of greenhouse tomatoes by 
Potato spindle tuber viroid  in the United States. Plant Disease  94:11, 1376. 
 
Luo, H., S.J. W
ylie and M.G.K. Jones. 2010. Identification of plant viruses using one-
dimensional gel electrophoresis and peptide mass fingerprints. Journal of Virological 
Methods 165(2): 297-301. 
 MAF response close out report. 2009. Detection of PSTVd in Cape gooseberry and tobacco. 2 
June 2009. 
 Malandraki, I., M. Papachristopoulou a nd N. Vassilakos. 2010. First report of Potato spindle 
tuber viroid (PSTVd) in ornamental plants in Greece. New Disease Reports  21: article 
9. 
 
Matsushita, Y., A. Kanda, T. Usugi , and S. Tsuda. 2008. First report of a Tomato chlorotic 
dwarf viroid  disease on tom
ato plants in Japan. Journal of General Plant Pathology  
74(2): 182-184.  
 Matsushita, Y., T. Usugi, and S. Ts uda. 2009. Host range and properties of Tomato chlorotic 
dwarf viroid . European Journal of Plant Pathology  124(2): 349-352.  
 Matsushita, Y., T. Usugi, and S. Tsuda. 2011. Distribution of tomato chlorotic dwarf viroid  in 
floral organs of tomato. European Journal of Plant Pathology  130: 441-447.  
 Matsuura, S., Y. Matsushita, R. Kozuka, S. Shimizu, and S. Tsuda. 2010. Transmission of 
Tomato chlorotic dwarf viroid  by bumblebees ( Bombus ignitus ) in tomato plants.  
European Journal of Plant Pathology  126(1): 111-115.  
 Olivier, T., E. Demonty, J. Govers, K. Belkhe ir, S. Steyer and C. Jongen. 2011. First report of 
a Brugmansia sp. infected by Tomato apical stunt viroid in Belgium. Plant Disease  
95(4): 495. 
 Plant and Food Research. 2010. Fresh facts: New Zealand Horticulture  2010. Plant and Food 
Research and Horticulture Ne w Zealand. Available online at 
http://www.plantandfood.co.nz/f ile/freshfacts-brochure-2010.pdf
 
 Querci, M., R.A. Owens, I. Bartoli, V.  Lazarte and L.F. Salazar. 1997. Evidence for 
heterologous encapsidation of Potato spindle tuber viroid  in particles of Potato 
leafroll virus . Journal of General Virology  78: 1207-1211. 
 Singh, R. P. 1970. Seed transmission of potato spindle tuber virus in tomato and potato. 
American Potato Journal 47: 225-227. 
 
 16    
Singh, R. P. and A.D. Di
lworth. 2009. Tomato chlorotic dwarf viroid  in the ornamental plant 
Vinca minor  and its transmission through tomato seed.  European Journal of Plant 
Pathology 123(1): 111-116.  
 
Singh, R. P., K.F.M. Ready and X. Nie. 2003. Viroids of solanaceous species. In: Viroids 
(Hadidi A., R. Flores J.W. Randles and Semancik J. S. Eds). CSIRO Publishing. 
Chapter 15: pp125-133. 
 Singh, R. P., Nie XianZhou, Mathuresh Singh. 1999. Tomato chlorotic dwarf viroid: an 
evolutionary link in the origin of pospiviroids.  Journal of General Virology  80(11): 
2823-2828.  
 
Stobbs, L.W., S. Greig, L. W
eaver, L. Shipp and G. Ferguson. 2009. The potential role of 
native weed species and bumblebees ( Bombus impatiens ) on the epidemiology of 
Pepino mosaic virus. Canadian Journal of Plant Pathology  31: 254-261. 
 Syller, J., W. Marczewski and J. Pawlowicz. 1997. Transmission by aphids of Potato spindle 
tuber viroid  encapsidated by Potato leafroll luteovirus  particles. European Journal of 
Plant Pathology 103: 285-289. 
 
Syller, J. and W
. Marczewski. 2001. Potato l eafroll virus-assisted aphid transmission of 
potato spindle tuber viro id to potato leafroll virus-resistant potato. Journal of 
Phytopathology 149(3/4): 195-201. 
 Van Toor, R.F. and D.A.J. Teulon. 2006. Insecticid e practice for aphid control in potatoes. New 
Zealand Plant Protection 59: 235-241. 
http://www.nzpps.org/journal/59/nzpp_592350.pdf  
 Verhoeven, J.T. J., C.C.C. Jansen, J.W. Ro enhorst, S. Steyer, D. Michelante and S. 
Bolivarlaan. 2007. First report of Potato spindle tuber viroid  in tomato in Belgium. 
Plant Disease  91(8): 1055. 
 Verhoeven, J. T. J., C.C.C. Jansen and J. W. Roenhorst. 2008. First report of pospiviroids 
infecting ornamentals in the Netherlands: Citrus exocortis viroid in Verbena sp., 
Potato spindle tuber viroid in Brugmansia suaveolens and Solanum jasminoides,  and 
Tomato apical stunt viroid in Cestrum sp. Plant Pathology 57: 399. 
 Verhoeven, J.T. J., C.C.C. Jansen and J.W. Roenhorst. 2008b. Streptosolen jamesonii  
'Yellow', a new host plant of Potato spindle tuber viroid . Plant Pathology  57(2): 399. 
 Verhoeven, J.T. J., M. Botermans, C.C.C. Jans en, and J.W. Roenhorst. 2010. First report of 
Tomato apical stunt viroid in the symptomless hosts Lycianthes rantonnetii and 
Streptosolen jamesonii in the Netherlands. Plant Disease 94(6): 791 
 Vovlas, C., D. Gallitelli and M. Conti. 1989. Pr eliminary evidence for an unusual mode of 
transmission in the ecology of Pelargonium zonate spot virus (PZSV). Pages 302-305 
in: 4
th Plant Virus Epidemiol. Wo rkshop. Montpellier, France.  
 Ward, L. I., J. Tang,  S. Veerakone, B.D. Qui nn, S.J. Harper, C. Delmiglio, G.R.G. Clover. 
2010. First report of Potato spindle tuber viroid  in Cape gooseberry ( Physalis 
peruviana) in New Zealand. Plant Disease 94(4): 479 
 
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