EPPO RNQP

NAME OF THE ORGANISM: Botrytis allii (BOTRAL)

GENERAL INFORMATION ON THE PEST

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

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: 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

Justification (if necessary):

Usually, B. allii is associated with "neck rot" of onions. Neck rot symptoms may also be induced by other Botrytis species, like B. byssoidea (Schwartz&Mohan 2008: APS compendium of Onion and Garlic diseases). Therefore the organism listed (here B. allii) is only one part of the problem.

2 – Status in the EU:

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

Presence in the EU:

Yes

Conclusion:

candidate

Justification (if necessary):

The pest is present in Austria, Belgium, Bulgaria, Denmark, Finland, France, Germany, Italy, Netherlands, poland, Romania and UK (CABI 1987).

HOST PLANT N°1: Allium cepa (ALLCE) for the Vegetable propagating and planting material (other than seeds) sector.

Origin of the listing:

RNQP Questionnaire

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:

The SEWG agreed that sets are a significant pathway of B. allii.

5 - Economic impact:

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

Yes

Justification:

In Finland, Botrytis allii caused 15-20% damage during storage in 1975-79 and was present on 80-90% of the spoilt harvested onions. The early weight losses during storage were mostly due to storage pathogens which spread via the onion sets used for propagation. This could be prevented by soaking the sets in benomyl solution [no longer registered in EU] before planting out. The unusually high fungus content of the sets resulted in a reduced yield (Tahvonen, 1981).
The incidence of umbel rot (flower blight) caused by Botrytis allii and B. cinerea ranged from 0.08 to 7.23% (average 4.26%) in the former GDR during 1984-88. Compared with healthy plants, seed yields of affected plants decreased by 44.2%. 1000-seed weight decreased by 17.4%, and other seed quality parameters (germination rate and ability, conductivity, and emergence) were adversely affected (Rudolph, 1990).

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

Medium

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:

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:

We have no data about the efficacy of fungicides against B. allii in set production (including sclerotia formation). In Germany fungicides are registered to control B. squamosa.

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:

Not recommended for listing as an RNQP: This pest/host/intended use combination meets all the criteria for RNQP status but the requirement for absence of visual symptoms on the traded material (current general 'Substantially free from' requirement in the EU) is considered to be sufficient.

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:

CABI (1987) Distribution map for Botrytis allii. Distribution Maps of Plant Diseases (Edition 4), Map 169;
Ellis MB & Waller JM (1974) Botrytis allii. CMI Descriptions of Fungi and Bacteria 433, Set No 44;
Rudolph M (1990) Umbel rot of onion (Allium cepa L.). Nachrichtenblatt Pflanzenschutz 44, pp.185-186;
Tahvonen R (1981) Storage fungi of onion and their control. Journal of the Scientific Agricultural Society of Finland 53, 27-41;