NAME OF THE ORGANISM: Pythium 1PYTHG

GENERAL INFORMATION ON THE PEST

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

Pythium spp.

Pest category:

Chromista

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?:

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?

No: Ornamental sector

If necessary, please list the species:

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

Not relevant

Conclusion:

Not candidate: Ornamental sector

Justification (if necessary):

For the Seed potato Sector, experts indicated that Pythium ultimum is mostly encountered. However experts concluded that more investigations and efforts to diagnose pest at the species level is needed. This would be necessary for a listing at the Species level. As long as measures are only based on symptoms for this pest, a listing at the Genus level is appropriate for this sector.
For the Vegetable reproductive and planting material (excluding seeds) Sector, and for the Ornamental sector, no EU Member State identified this entry as important and justified to keep Pythium listed at a higher level than the species level. No EU Member State proposed to replace this entry by pests listed at the Species level.
[identification by France was an error]

2 – Status in the EU:

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

Presence in the EU:

Yes

List of countries (EPPO Global Database):

Conclusion:

candidate

Justification (if necessary):

The pest is worldwide in distribution.

HOST PLANT N°1: Chrysanthemum x grandiflorum (Dendranthema x grandiflorum) (CHYHO) for the Ornamental sector.

Origin of the listing:

Commission Directive 93/49/EEC

Plants for planting:

Plants intended for planting

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:

Wilting may be caused by infection of the base of plants by Pythium spp. hampering upward water transport. Seedlings, cuttings or transplanted material of ornamental plants rot near the soil surface and die. Such damping off or collar rot is caused by a variety of soil fungi, including Pythium spp. (EPPO, 1998). Root-knot symptoms may also be caused by Pythium spp. in association with root-knot nematodes.
Plants for planting are a pathway, however because of the wide host range, transport in soil water etc. and longevity of inoculum sources in the environment, planting material (transplants) are not considered to be the main pathway for introduction under outdoor field conditions.
Transplants produced under at-risk situations could be considered the main pathway if the intended use was for a protected facility that used uninfested soil media and had been thoroughly cleaned of potential infection sources before use.

5 - Economic impact:

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

Yes

Justification:

Many records are noted for economic impact, e.g. P. splendens and P. ultimum were shown to be very important pathogens, causing stem rot in cuttings and growth retardation and seedling death in this species in Germany (Kelling, 1985).

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

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?

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?

Conclusion:

Justification:

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?

Conclusion:

Justification:

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

Conclusion:

Justification:

CONCLUSION ON THE STATUS:

Disqualified: No EU Member State considered this entry as important in the answers to the RNQP Questionnaire [identification by FR was an error] and gave justification(s) for a listing at a higher level than the species level. This entry will be covered by the 'substantially free from' requirement that will remain in the ornamental EU Marketing Directives.

8 - Tolerance level:

Is there a need to change the Tolerance level:

Proposed Tolerance levels:

Delisting.

9 - Risk management measures:

Is there a need to change the Risk management measure:

Proposed Risk management measure:

Delisting.

REFERENCES:

EPPO (1998) PP 2/13 (1) Good plant protection practice. Ornamental Plants under Protected Cultivation. Bulletin OEPP/EPPO Bulletin 28, 363–386;
Kelling K (1985) Pythium species causing rot diseases in ornamentals. Nachrichtenblatt für den Pflanzenschutz in der DDR 39 No.9 pp.191-193;