EPPO RNQP

NAME OF THE ORGANISM: Aphelenchoides besseyi (APLOBE)

GENERAL INFORMATION ON THE PEST

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

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: Cereals (including rice) sector

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

Not relevant

Conclusion:

Candidate: Cereals (including rice) sector

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):

Bulgaria (1993); Hungary (1992); Italy (2008)

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 a candidate for the RNQP status according to the IIA2AWG

HOST PLANT N°1: Oryza (1ORYG) for the Cereals (including rice) sector.

Origin of the listing:

IIA2AWG

Plants for planting:

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:

Rice seeds are considered the main pathway (EU COM, 2016 and CABI, 2016). On rice in Italy, usually only few rice lots are infested with 0.17 - 0.33 nematodes/100 seeds corresponding to 5 - 10 nematodes/3000 seeds without any damage to the crop occurring or yield decreasing. The economic damage threshold density is 300 live nematodes/100 seed (CABI, 2016). Rice husks and stubble could also be a potential pathway if left on the soil without deep ploughing, although no data have been found in literature regarding infestations related to this pathway. It can also be transmitted in flood water in lowland rice but the survival of nematodes in water decreases as temperature increases from 20 to 30°C (CABI, 2016). The other potential host, strawberry, is not normally grown in rotation with rice (EU COM, 2016).

5 - Economic impact:

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

Yes

Justification:

In the 1950s figures for yield losses for susceptible cultivars in the USA were 17.5, 4.9 and 6.6% in different years and 10-30% in Japan. Another study there reported yield losses of 44.9, 34.7 and 24.2% when rice plant infestation rates were 57, 34 and 18%, respectively. A. besseyi has been controlled in the USA by seed treatment and the use of resistant cultivars and is no longer a pest. A. besseyi also disappeared from Japan but has re-occurred, the economic value of infected discoloured grain being reduced if infection exceeds 0.7% (CABI, 2016).

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

Major

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?

Conclusion:

Candidate

Justification:

Remark: Oryza and Fragaria do not alternate each other in a crop rotation. Other economically important crops (such as onion, garlic, chinese cabbage, cucumber, soybean and maize) and the flower species are only incidental hosts.

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:

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.

8 - Tolerance level:

Is there a need to change the Tolerance level:

Proposed Tolerance levels:

Zero tolerance, based on the following measures.

9 - Risk management measures:

Is there a need to change the Risk management measure:

Yes

Proposed Risk management measure:

For all categories of material:
(a) The seeds originate in area known to be free from Aphelenchoides besseyi;
or
(b) The seeds have been officially tested by appropriate nematological tests on a representative sample from each lot and have been found free from Aphelenchoides besseyi;
or
(c) The seeds have been subjected to an appropriate hot water treatment or other appropriate treatment against Aphelenchoides besseyi.

REFERENCES:

CABI (Centre for Agricultural Bioscience International), online, 2016. Datasheets Aphelenchoides besseyi (rice leaf nematode). Invasive species compendium. CABI, Wallingford, UK. Available from http://www.cabi.org/isc/datasheet/6378;
EU COM (2016) Recommendation of the Working Group on the Annexes of the Council Directive 2000/29/EC – Section II – Listing of Harmful Organisms as regards the future listing of Aphelenchoides besseyi (rice leaf nematode);