| Legend |
|---|
| Justification for qualification based on EPPO PM 4 Standards |
| Justification for disqualification |
| Additional or non-conclusive information |
| Standard text |
NAME OF THE ORGANISM: Colletotrichum acutatum sensu lato (COLLAC)
GENERAL INFORMATION ON THE PEST
Name as submitted in the project specification (if different):
Colletotrichum acutatum
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):
Remark on taxonomy: Anthracnose is a major disease of cultivated strawberry, caused by two species complexes of the fungus referred to as C. acutatum and C. gloeosporioides. The C. acutatum complex is considered to be the dominant cause of strawberry anthracnose (in Baroncelli et al., 2015). The C. gloeosporioides complex includes C. fragariae, which is now considered synonymous with a new species C. theobromicola (Weir et al., 2012). C. gloeosporioides is found only occasionally on strawberry in Europe (in Baroncelli et al., 2015).
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):
Austria (1999); Belgium (2017); Bulgaria (2009); Czech Republic (2013); Denmark (2005); Finland (2011); France (1994); Germany (1998); Hungary (2019); Ireland (2007); Italy (2015); Lithuania (2007); Malta (2005); Netherlands (2013); Portugal (2011); Slovenia (1999); Spain (2019); Sweden (2005)
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/).
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:
Qualified
Justification (if necessary):
EPPO Standard PM 4/11 Certification scheme for strawberry recommends inspection and testing for Colletotrichum acutatum, but with 0% tolerance in visual inspection.
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:
Plant: primary source of infection in annual strawberry production fields. In perennial strawberry production fields the primary source is plant material and plant debris: production of conidia which can be splash dispersed by water, movement of workers, machines, animals. Weather conditions are also important: disease spread is minimal in dry cool weather, while the disease can be spread rapidly under warm, rainy conditions (Smith 1998)
Seed: probably, it is seed transmitted in other crops (Falconía & Yánez-Mendizábal, 2018)
Soil: contaminated soil on transplants also primary source in perennial strawberry production fields (Smith 1998). The pathogen can survive in strawberry plant parts in soil or on the soil surface for three years (Parikka et al., 2016).
Many Colletotrichum species may be seed-borne and can survive well in soil by growing saprophytically on dead plant fragments, and can be spread via water-splash dispersal of conidia and air transmission of ascospores from the sexual morph (Nicholson & Moraes 1980).
The source of inoculum for root infection is uncertain. Conidia or possibly appressoria on the upper parts of the plant can be washed down to the crown and roots during digging, washing, and transplanting, and mechanical damage and stress caused by these processes may facilitate root infection (Calleja et al., 2005).
Seed: probably, it is seed transmitted in other crops (Falconía & Yánez-Mendizábal, 2018)
Soil: contaminated soil on transplants also primary source in perennial strawberry production fields (Smith 1998). The pathogen can survive in strawberry plant parts in soil or on the soil surface for three years (Parikka et al., 2016).
Many Colletotrichum species may be seed-borne and can survive well in soil by growing saprophytically on dead plant fragments, and can be spread via water-splash dispersal of conidia and air transmission of ascospores from the sexual morph (Nicholson & Moraes 1980).
The source of inoculum for root infection is uncertain. Conidia or possibly appressoria on the upper parts of the plant can be washed down to the crown and roots during digging, washing, and transplanting, and mechanical damage and stress caused by these processes may facilitate root infection (Calleja et al., 2005).
5 - Economic impact:
Are there documented reports of any economic impact on the host?
Yes
Justification:
Colletotrichum acutatum can cause anthracnose fruit rot and anthracnose crown rot in strawberry (just like C. gloeosporioides). Crown infections are often initiated in the nursery but may not be apparent until after plants are set in production fields. The fungus continues to grow in the infected plant, which may later die suddenly following warm weather in the fall or in the following spring. There is little spread of crown rot in annual fruit production fields (Smith, 1998).
C. acutatum produces a wide range of symptoms on various tissues of the strawberry plant. Symptoms include sunken, brown, circular spots which darken as the fruit ripens with salmon coloured spore masses if there are dry conditions. On the plant, the pathogen causes leaf spots and cankers on stolons and stalks (Defra factsheet, 2006).
The pathogen is not a general necrotroph on all tissues of strawberry, but it is most important as a necrotroph causing serious fruit rot. Lesions on petioles are produced from quiescent infections after the plants are established. Later, flowers may be attacked, and ripe and unripe fruit develop symptoms normally referred to as black spot. Strawberry is unique in that roots and crowns can be infected by C. acutatum causing severe stunting or even plant death.
The disease is the second most important pathogen of strawberry after Botrytis cinerea. There are reports of up to 80% losses in unsprayed crops in France (CABI, 2021). There are more details of losses in the USA, with Floridian crops experience losses greater than 50% in commercial fields (Wang et al., 2019). It was historically thought of as a warm weather disease limited to the southern states, although there is an increasing level of incidence in the more northern states with losses experienced of up to 100% (University of Ohio, 2023).
C. acutatum produces a wide range of symptoms on various tissues of the strawberry plant. Symptoms include sunken, brown, circular spots which darken as the fruit ripens with salmon coloured spore masses if there are dry conditions. On the plant, the pathogen causes leaf spots and cankers on stolons and stalks (Defra factsheet, 2006).
The pathogen is not a general necrotroph on all tissues of strawberry, but it is most important as a necrotroph causing serious fruit rot. Lesions on petioles are produced from quiescent infections after the plants are established. Later, flowers may be attacked, and ripe and unripe fruit develop symptoms normally referred to as black spot. Strawberry is unique in that roots and crowns can be infected by C. acutatum causing severe stunting or even plant death.
The disease is the second most important pathogen of strawberry after Botrytis cinerea. There are reports of up to 80% losses in unsprayed crops in France (CABI, 2021). There are more details of losses in the USA, with Floridian crops experience losses greater than 50% in commercial fields (Wang et al., 2019). It was historically thought of as a warm weather disease limited to the southern states, although there is an increasing level of incidence in the more northern states with losses experienced of up to 100% (University of Ohio, 2023).
What is the likely economic impact of the pest irrespective of its infestation source in the absence of phytosanitary measures? (= official measures)
Medium to 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?
No
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:
Candidate
Justification:
Impact can vary depending on weather conditions. Significant impacts have been recorded.
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:
Diseases caused by C. acutatum are best controlled by exclusion (not introducing the pathogen into the field) (Mertely et al., 2022).
Fungicides are the most common control measures, often with QoI fungicides (Debode et al., 2014).
From the Defra factsheet (2006):
There are no totally effective chemicals to control against strawberry black spot. However, the following cultural measures can help to prevent the disease getting a hold:
Nitrogen: Limit nitrogen applications to 40 kg/ha/yr on June bearers, and 80 kg/ha/yr on ever bearers.
Mulch: Apply a straw mulch between rows and on any plastic mulch to limit dispersal of spores through water splash.
Picking: Minimize the amount of ripe fruit on the crop at any one time by keeping picking intervals as short as possible.
No Paraquat: Avoid Paraquat for weed and runner control as it encourages development of the fungus. (no longer available)
Plant debris: Wherever possible, collect plant debris from the field after harvest and either burn or bury it deeply.
Crop management: Improve air circulation by crown thinning, good weed control and removal of rotten and over-ripe berries as these will all help reduce the risk. Consider moving off June bearers after harvest and possibly again in the spring. If possible debris should be collected and destroyed.
Crop duration: Keeping a crop for only 1 or 2 years greatly reduces the risk of development and spread of this disease.
Fungicides are the most common control measures, often with QoI fungicides (Debode et al., 2014).
From the Defra factsheet (2006):
There are no totally effective chemicals to control against strawberry black spot. However, the following cultural measures can help to prevent the disease getting a hold:
Nitrogen: Limit nitrogen applications to 40 kg/ha/yr on June bearers, and 80 kg/ha/yr on ever bearers.
Mulch: Apply a straw mulch between rows and on any plastic mulch to limit dispersal of spores through water splash.
Picking: Minimize the amount of ripe fruit on the crop at any one time by keeping picking intervals as short as possible.
No Paraquat: Avoid Paraquat for weed and runner control as it encourages development of the fungus. (no longer available)
Plant debris: Wherever possible, collect plant debris from the field after harvest and either burn or bury it deeply.
Crop management: Improve air circulation by crown thinning, good weed control and removal of rotten and over-ripe berries as these will all help reduce the risk. Consider moving off June bearers after harvest and possibly again in the spring. If possible debris should be collected and destroyed.
Crop duration: Keeping a crop for only 1 or 2 years greatly reduces the risk of development and spread of this disease.
7- Is the quality of the data sufficient to recommend the pest to be listed as a RNQP?
Yes
Conclusion:
Candidate
Justification:
There are enough data to make a decision
CONCLUSION ON THE STATUS:
Recommended for listing as an RNQP, based on data and EPPO PM 4 Standard.
8 - Tolerance level:
Is there a need to change the Tolerance level:
No
Proposed Tolerance levels:
9 - Risk management measures:
Is there a need to change the Risk management measure:
No
Proposed Risk management measure:
REFERENCES:
- Baroncelli R, Zapparata A, Sarrocco S, Sukno SA, Lane CR, Thon MR, Vannacci G, Holub E & Sreenivasaprasad S (2015) Molecular diversity of anthracnose pathogen populations associated with UK strawberry production suggests multiple introductions of three different Colletotrichum species. PLoS ONE 10(6): e0129140. doi:10.1371/journal.pone.0129140
- CABI (2021) Colletotrichum acutatum (black spot of strawberry). Available: Colletotrichum acutatum (black spot of strawberry) | CABI Compendium (cabidigitallibrary.org). Accessed: 15/08/2024;
- Cannon PF, Damm U, Johnston PR & Weir BS (2012) Colletotrichum – current status and future directions. Studies in Mycology 73: 181–213;
- Damm U, Cannon PF, Woudenberg JHC & Crous PW (2012) The Colletotrichum acutatum species complex. Studies in Mycology 73: 37–113;
- Debode J, van Hemerlrijck W, Xu X-M, Maes M, Creemers P & Heungens K (2014) Latent entry and spread of Colletotrichum acutatum (species complex) in strawberry fields. Plant Pathology 64, 385-395;
- Defra factsheet (2006) Strawberry black spot. Available: Strawberry black spot (defra.gov.uk). Accessed: 15/08/2024;
- Falconía CE & Yánez-Mendizábal V (2018) Efficacy of UV-C radiation to reduce seedborne anthracnose (Colletotrichum acutatum) from Andean lupin (Lupinus mutabilis). Plant Pathology 67: 831-838;
- Mertely JC, Forcelini BB & Peres NA (2022) Root necrosis of strawberry caused by Colletotrichum acutatum. University of Florida, IFAS PP-211 (February 18, 2022). https://edis.ifas.ufl.edu/publication/PP128
- Parikka P, Lemmetty A, Sundelin T, Strømeng GM & Stensvand A. (2016). Survival of Colletotrichum acutatum in plant residue. Acta Horticulturae 1117, 177-180. DOI: 10.17660/ActaHortic.2016.1117.28
- Smith BJ (1998) Anthracnose fruit rot (black spot). In Compendium of strawberry diseases (second edition). Ed. Maas JL. APS Press, the American Phytopathological Society, St. Paul, Minnesota, USA, pp 31-22.