| Legend |
|---|
| Justification for qualification based on EPPO PM 4 Standards |
| Justification for disqualification |
| Additional or non-conclusive information |
| Standard text |
NAME OF THE ORGANISM: Chondrostereum purpureum (STERPU)
GENERAL INFORMATION ON THE PEST
Name as submitted in the project specification (if different):
Pest category:
Fungi
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: Fruits (including hops) 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:
- Candidate: Fruits (including hops) sector
Justification (if necessary):
2 – Status in the EU:
Is this pest already a quarantine pest for the whole EU?
No
Presence in the EU:
Yes
List of countries (EPPO Global Database):
-
Conclusion:
Candidate
Justification (if necessary):
The pest is reported from Finland (Vartiamäki et al., 2009), Netherlands (De Jong et al., 1990) and various other EPPO countries.
HOST PLANT N°1: Juglans regia (IUGRE) for the Fruits (including hops) sector.
Origin of the listing:
Commission Implementing Directive (EU) 2014/98/EU and Commission Implementing Regulation (EU) 2019/2072
Plants for planting:
Plants intended for planting
3 - Is the pest already listed in a PM4 standard on the concerned host plant?
No
Conclusion:
Evaluation continues
Justification (if necessary):
There are no EPPO PM4 Standard for Juglans.
In the responses to the RNQP questionnaire, PL supported deregulation because of acceptable impact.
Remark: In PM 4 Standards for some other species e.g. pome fruits, it is mentioned iunder “inspection of other pests” (PM4/27).
In PM4/29 and PM4/30 it is not mentioned, although Chondrostereum purpureum can cause symptoms in these Prunus spp.
It is mentioned in PM4/31 hazelnut: Adequate control of pests should be ensured, in particular Mikomyia coryli, Cryptosporiopsis coryli, Chondrostereum purpureum, Nectria galligena, Phyllactinia guttata. Indicating it is already present in the environment.
It is mentioned in e.g. PM2/18(1) guidelines on good plant protection practice: pome fruits.
“Various other fungi, causing relatively unimportant cankers of apple and pear… or silver leaf disease (Chondrostereum purpureum), can be treated in the same way.”
In the responses to the RNQP questionnaire, PL supported deregulation because of acceptable impact.
Remark: In PM 4 Standards for some other species e.g. pome fruits, it is mentioned iunder “inspection of other pests” (PM4/27).
In PM4/29 and PM4/30 it is not mentioned, although Chondrostereum purpureum can cause symptoms in these Prunus spp.
It is mentioned in PM4/31 hazelnut: Adequate control of pests should be ensured, in particular Mikomyia coryli, Cryptosporiopsis coryli, Chondrostereum purpureum, Nectria galligena, Phyllactinia guttata. Indicating it is already present in the environment.
It is mentioned in e.g. PM2/18(1) guidelines on good plant protection practice: pome fruits.
“Various other fungi, causing relatively unimportant cankers of apple and pear… or silver leaf disease (Chondrostereum purpureum), can be treated in the same way.”
4 - Are the listed plants for planting the main* pathway for the "pest/host/intended use" combination? (*: significant compared to others):
No
Conclusion:
Not candidate
Justification:
Chondrostereum purpureum is a wound pathogen that causes silverleaf disease in more than 230 woody species, including major fruit crops such as apple and pear (e.g. Spiers et al., 1998; Grinsberg et al., 2020).
From herbaria in USA and Canada Chondrostereum purpureum was not often collected from Juglandaceae (1-3%) compared to Betulaceae (45%) and Salicaceae (20%) (Setliff 2002).
This basidiomycete fungus disseminates through airborne spores from different inoculum sources such as infected fruit orchard, windblown trees, logged areas, woodpiles and pruned branches; the spores reach wounded wood, like grafts and pruning cuts, and causes infection (cited from Grinsbergs et al., 2020). Fructifications of C. purpureum form on dead wood in autumn. The dispersal of basidiospores form the fruiting bodies begins in autumn and continues until the following June. Basidiospores are released when the fruiting bodies are wet and the temperature is above freezing. They infect wood through fresh wounds, such as pruning cuts, spits for grafts or stubs left where branches have broken under heavy snow or ice. Infections of wounds more than 1 month old is uncommon.
Winter and early spring are the most critical times for infection. When infection occurs in spring, the first silvering of leaves may be visible about 1 month later. Inoculation studies indicate that apple trees are most susceptible to infection from December to April (Fujita, 1998; Biggs, 2017).
Forests with greatest vulnerability are those subjected (1) to physical forces that cause stem injuries to susceptible trees, (2) to environmental conditions conducive for infection and (3) to high levels of basidiospore inoculum from fruiting bodies on hardwood slash that result from timber harvesting and storm damage (Setliff, 2002). In orchard situations the fungus can be controlled through good cultural practices e.g. by cleaning up any dead wood which might be infected before pruning and decontaminate the pruning tools.
Plants for planting are not the major pathway since the pathogen is already present in Europe, widespread and can be dispersed by spores.
From herbaria in USA and Canada Chondrostereum purpureum was not often collected from Juglandaceae (1-3%) compared to Betulaceae (45%) and Salicaceae (20%) (Setliff 2002).
This basidiomycete fungus disseminates through airborne spores from different inoculum sources such as infected fruit orchard, windblown trees, logged areas, woodpiles and pruned branches; the spores reach wounded wood, like grafts and pruning cuts, and causes infection (cited from Grinsbergs et al., 2020). Fructifications of C. purpureum form on dead wood in autumn. The dispersal of basidiospores form the fruiting bodies begins in autumn and continues until the following June. Basidiospores are released when the fruiting bodies are wet and the temperature is above freezing. They infect wood through fresh wounds, such as pruning cuts, spits for grafts or stubs left where branches have broken under heavy snow or ice. Infections of wounds more than 1 month old is uncommon.
Winter and early spring are the most critical times for infection. When infection occurs in spring, the first silvering of leaves may be visible about 1 month later. Inoculation studies indicate that apple trees are most susceptible to infection from December to April (Fujita, 1998; Biggs, 2017).
Forests with greatest vulnerability are those subjected (1) to physical forces that cause stem injuries to susceptible trees, (2) to environmental conditions conducive for infection and (3) to high levels of basidiospore inoculum from fruiting bodies on hardwood slash that result from timber harvesting and storm damage (Setliff, 2002). In orchard situations the fungus can be controlled through good cultural practices e.g. by cleaning up any dead wood which might be infected before pruning and decontaminate the pruning tools.
Plants for planting are not the major pathway since the pathogen is already present in Europe, widespread and can be dispersed by spores.
5 - Economic impact:
Are there documented reports of any economic impact on the host?
No
Justification:
There are no reports on impact on Juglans regia. From herbaria in USA and Canada Chondrostereum purpureum was not often collected from Juglandaceae (1-3%) compared to Betulaceae (45%) and Salicaceae (20%) (Setliff 2002).
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:
In orchard situations the fungus can be controlled through good cultural practices e.g. by cleaning up any dead wood which might be infected before pruning and decontaminate the pruning tools.
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: there are no evidence of economic impact on Juglans regia. Plant for planting is not considered to be the main pathway.
8 - Tolerance level:
Is there a need to change the Tolerance level:
Yes
Proposed Tolerance levels:
Delisting
9 - Risk management measures:
Is there a need to change the Risk management measure:
Yes
Proposed Risk management measure:
Delisting
REFERENCES:
- De Jong MD, Scheepens PC & Zadoks JC (1990). Risk analysis for biological control: A Dutch case study in biocontrol of Prunus serotina by the fungus Chondrostereum purpureum. Plant Disease 74, 189-194.
- Grinbergs D, Chilian J, Carrasco-Fernández J, France A, Moya-Elizondo E & Gerding M. (2020). A PCR-Based method for the rapid detection of Chondrostereum purpureum in apple. Plant Disease 104: 702-707.
- Setliff EC (2002). The wound pathogen Chondrostereum purpureum, its history and incidence on trees in North America. Australian Journal of Botany 50(5) 645 – 651.
- Sharma S, Nayak RK & Singh J. insect pests and Diseases of temperate Fruits and their Management.
- Vartiamäki H, Hantula J, Uotila A (1990). Susceptibility of silver birch pruning wounds to infection by white-rot fungus (Chondrostereum purpureum), a potential bioherbicide. Silva Fennica 43(4), 537–547.