EPPO RNQP

NAME OF THE ORGANISM: Potato spindle tuber viroid (PSTVD0)

GENERAL INFORMATION ON THE PEST

Name as submitted in the project specification (if different to the preferred name):

Pest category:

Viruses and viroids

1- Identity of the pest/Level of taxonomic listing:

Is the organism clearly a single taxonomic entity and can it be adequately distinguished from other entities of the same rank?

Yes

Is the pest defined at the species level or lower?:

Yes

Can listing of the pest at a taxonomic level higher than species be supported by scientific reasons or can species be identified within the taxonomic rank which are the (main) pests of concern?

Not relevant: Vegetable propagating and planting material (other than seeds) sector

Is it justified that the pest is listed at a taxonomic rank below species level?

Not relevant

Conclusion:

Candidate: Vegetable propagating and planting material (other than seeds) sector

2 – Status in the EU:

Is this pest already a quarantine pest for the whole EU?

Yes

Presence in the EU:

Yes

List of countries (EPPO Global Database):

Austria (2011); Croatia (2014); Czech Republic (2014); Germany (2011); Italy (2011); Malta (2013); Poland (2016); Slovenia (2013); Spain (2011)

Conclusion:

candidate

Justification (if necessary):

Data of the presence of this pest on the EU territory are available in EPPO Global Database (https://gd.eppo.int/).
This pest is considered to be already a quarantine pest for the whole EU (annex IA1 of the directive 2000/29/EC). However, in view of its presence in the EU (see data of the presence of this pest on the EU territory available in EPPO Global Database: https://gd.eppo.int/), classification within the directive should be revised. This pest is not evaluated in the context of the EU RNQP Project but because it was submitted for evaluation by the Working Party on Phytosanitary Regulation (WPPR, 2016). As a consequence, evaluation continues.

HOST PLANT N°1: Capsicum annuum (CPSAN) for the Vegetable propagating and planting material (other than seeds) sector.

Origin of the listing:

EFSA PRA (EFSA PLH, 2011)

Plants for planting:

Plants intended for planting, other than seeds

3 - Is the pest already listed in a PM4 standard on the concerned host plant?

Conclusion:

Evaluation continues

4 - Are the listed plants for planting the main* pathway for the "pest/host/intended use" combination? (*: significant compared to others):

Yes

Conclusion:

Candidate

Justification:

Although PSTVd in Capsicum annum seed has not been reported, a high probability rating of this is suggested by analogy, but this rating is associated with a high uncertainty (EFSA-PLH, 2011). However, if present, any infection arising from seed will likely spread rapidly to neighbouring susceptible plant species by mechanical means in the nursery (EFSA-PLH, 2011). Therefore young plants as plants for planting (arising from infected seed, or mechanical means from other hosts), can be considered a main pathway for this pest/host/intended use combination.

5 - Economic impact:

Are there documented reports of any economic impact on the host?

Yes

Justification:

PSTVd has been recorded in three pepper crops in New Zealand. The infected pepper plants displayed only very mild symptoms (i.e. a certain “waviness” or distortion of the leaf margins near the top of the plants). However, after artificial (mechanical) inoculation of PSTVd to pepper cv. Yolo Wonder, fruit size was significantly reduced. It was concluded (in the absence of other pospiviroids) that PSTVd has the potential to cause minor damage in pepper (EFSA, 2011). Peppers may be grown on premises growing other susceptible crops such as tomato, so could act as a source of transmission during the growing season.

What is the likely economic impact of the pest irrespective of its infestation source in the absence of phytosanitary measures? (= official measures)

Minor

Is the economic impact due to the presence of the pest on the named host plant for planting, acceptable to the propagation and end user sectors concerned?

Yes

Is there unacceptable economic impact caused to other hosts (or the same host with a different intended use) produced at the same place of production due to the transfer of the pest from the named host plant for planting?

Yes

Conclusion:

Candidate

Justification:

The infected pepper plants displayed only very mild symptoms (i.e. a certain “waviness” or distortion of the leaf margins near the top of the plants). However, after artificial (mechanical) inoculation of PSTVd to pepper cv. Yolo Wonder, fruit size was significantly reduced. It was concluded (in the absence of other pospiviroids) that PSTVd has the potential to cause minor damage in pepper (EFSA-PLH, 2011). Peppers may be grown on premises growing other susceptible crops such as tomato and potato, so could act as a source of transmission during the growing season.
Remark: there may be financial losses due to the costs of testing for and removing asymptomatic infected plants and these costs can be considerable. For example, In the Netherlands in 2006-2007 ornamental plants infected with PSTVd were traced (costing the government 700,000 Euros) and destroyed (costing industry 3 to 5 million Euros). The plants did not show any noticeable symptoms, but were destroyed to prevent infection spreading to tomato and potato crops.

6 - Are there feasible and effective measures available to prevent the presence of the pest on the plants for planting at an incidence above a certain threshold (including zero) to avoid an unacceptable economic impact as regards the relevant host plants?

Yes

Conclusion:

candidate

Justification:

There is no management option that can prevent infestation other than exclusion and avoiding the use of infected plants (EFSA-PLH, 2011). Since tomato pospiviroid infections result in variable symptoms, requirements for using plant propagation material (including seeds) that is certified as free from pospiviroids, based on surveillance and targeted tests, should be an effective measures. This position is reinforced by the situation observed on PSTVd: the official measures significantly reduced the overall level of PSTVd circulating within the EU territory, and the incidence of this pathogen. However it is not possible to conclude whether the reduction in PSTVd prevalence in ornamentals has led to a reduction of outbreaks in potato, tomato and pepper productions.

7- Is the quality of the data sufficient to recommend the pest to be listed as a RNQP?

Yes

Conclusion:

Candidate

Justification:

CONCLUSION ON THE STATUS:

Recommended for listing as an RNQP, based on data. This pest would qualify for RNQP status if it were to be deregulated as a quarantine pest, but the SEWG makes no recommendation on the removal of the quarantine pest status. Moreover an alternative to the listing under the RNQP Status could be to recommend, in the risk management measures for tomato, isolation from other potential sources of infection, including other infected host plants.

8 - Tolerance level:

Is there a need to change the Tolerance level:

Proposed Tolerance levels:

9 - Risk management measures:

Is there a need to change the Risk management measure:

Proposed Risk management measure:

REFERENCES:

EFSA Panel on Plant Health (PLH) (2011) Scientific Opinion on the assessment of the risk of solanaceous pospiviroids for the EU territory and the identification and evaluation of risk management options. EFSA Journal 2011;9(8):2330 [132 pp.]. doi:10.2903/j.efsa.2011. 2330; www.efsa.europa.eu/efsajournal;
MAF (2012) Import Risk Analysis: Tomato and Capsicum seed for sowing from all countries. Ministry of Agriculture and Forestry of New-Zealand, Information Bureau. Available at: http://www.mpi.govt.nz/document-vault/2887;