Regulated Non-Quarantine Projects

Two EU funded projects for the benefit of the whole EPPO region

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Justification for qualification based on EPPO PM 4 Standards
Justification for disqualification
Additional or non-conclusive information
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NAME OF THE ORGANISM: Aphelenchoides blastophthorus (APLOBL)


GENERAL INFORMATION ON THE PEST

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

Pest category:
 
Nematoda


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):
 
Remark: DE suggested to list all Aphelenchoides at genus level to reduce diagnostic workload. Although differentiation between species may be difficult, the Fruit SEWG suggested to perform an assessment at species level. If needed, measures addressing the risk with different Aphelenchoides species can be defined.

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):
 
Aphelenchoides blastophthorus has been reported in various host plants in Belgium, Cyprus, Czech Republic, Germany, Italy, Netherlands, Slovenia (PESI, 2024).

HOST PLANT N°1: Fragaria (1FRAG) 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?
 
Yes
 
Conclusion:
 
Evaluation continues

 
Justification (if necessary):
 
The pest is listed in EPPO Standard PM4-11 Certification scheme for strawberry. However, when responding to the questionnaire, NL considered that economic impact was acceptable and supported deregulation. Evaluation continues with a focus on the economic impact.

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:
 
Aphelenchoides blastophthorus is a polyphagous leaf nematode, known to parasitize on (perennial) flowers and weeds like sheperd’s purse (Capsella bursa-pastoris), dandelion (Taraxacum officinale), Rumex spp., Campanula spp., wild strawberry, Anchusa, Anemone, Begonia, Caltha, Cephalaria, Convallaria, Dipsacus, Geum, Hepatica, Iris, Lomelosia caucasica, Narcissus, Trollius, Viola (Ellis 2001-2024, Haukeland, 2003).
A. blastophthorus can also be a pest in commercial strawberries. It was detected in Norwegian strawberry fields as early as 1972 and Støen (1987, cited in Haukeland Salinas 2003) confirmed in experiments that it damaged strawberry plants. In other strawberry-producing countries, the nematode has not been reported to be a problem in 2003 (Haukeland Salinas, 2003), but more recently Consoli et al. (2021) reported the leaf nematode from strawberry in Switzerland.
Surveys have shown that it could survive on gray mold (Botrytis cinerea) (Hooper 1975), and that it can also live on several different soil-dwelling fungi, e.g. black scab, mold and some Fusarium species (Haukeland Salinas, 2003).
Less is known about survival of A. blastophthorus in the field. The nematode occurs naturally on a wide range of perennial weed species, A. blastophthorus can spread from infected weeds to strawberries if they grow close together. It is also likely that the nematode can survive on fungi in soil, but information is lacking on how long A. blastophthorus can survive on fungi in soil or whether it can infect strawberry plants from soil (Haukeland Salinas, 2003).
The nematode can be transported with plant material, however Norwegian research indicated that the nematode can also move into the field from host plants growing on the field margins. Within 4 years the nematode was also found on strawberry plants in the middle of the field. Strawberry plants can be infected with A. blastophthorus without clear symptoms, and this can be a problem in particular for certification programs (Haukeland Salinas, 2003).
Plants for planting is considered to be a significant pathway.

5 - Economic impact:

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

Justification:
 
A. blastophthorus can cause similar symptoms as e.g. A. fragariae. Foliar nematodes live in the crown of the strawberry plant and where they feed on young, developing leaves. The nematodes spread via runners, but can also spread from plant to plant when there is high humidity and in years with a lot of rain, leaf nematodes can become an increasing problem. There are no data on the extent of yield loss caused by A. blastophthorus (Haukeland Salinas, 2003). Consoli et al (2019) detected A. blastophthorus on strawberry plants in Switzerland, these plants did not show any characteristic symptoms of foliar nematodes.

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?
 
No

Conclusion:
 
Not candidate

Justification:
 
A. blastophthorus seems to be a relatively new pest on strawberry, only reported as pest of strawberry in Norway. The Fruit SEWG considered that specific data of economic impact by this species was lacking. There is no clear evidence of possible indirect economic impact to other hosts (e.g. flowers and other ornamentals).

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:
 

Justification:
 
Healthy runners (certified stock enable growers to start clean)
Hot water treatments of runners before planting effectively control Aphelenchoides spp. (Qui et al., 1993)
If a field becomes infected:
As for other foliar nematodes, removing (rouging) and disposal of symptomatic plants as soon as they appear can help to minimize the spread of nematodes to other plants (McElroy, 1972). In addition to rogueing of infested plants and propagating from clean mother plants, minimizing surface moisture on plants and contact between plants, planting on ridges, avoiding splashing water from sprinkler irrigation, and rooting runners in containers placed in the row can help to minimize nematode spread in the field (McElroy 1972; Siddiqi 1975; cited in Westerdahl & Bello, 2023)

7- Is the quality of the data sufficient to recommend the pest to be listed as a RNQP?
 
No
 
Conclusion:
 

Justification:
 
Lack of data on economic impact. The assessment is based on information available from experience of Norway and Switzerland.

CONCLUSION ON THE STATUS:
 
Disqualified: specific data of economic impact is lacking.


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

Justification (if necessary):
 
Remark: in most situations, the risk with this pest will be covered by the measures implemented on other Aphelenchoides species.

REFERENCES: