EPPO Alert list – Curtobacterium flaccumfaciens pv. poinsettiae



Curtobacterium flaccumfaciens pv. poinsettiae was first described in 1942 in the USA and is associated with a disease causing leaf spots, stem rots and cankers on poinsettias. Considering the recent detection of the bacterium in Germany, its occasional findings in several European countries, and the conclusions of Dutch and German PRAs underlining the potential risks that the bacterium could present to glasshouse poinsettia production, the EPPO Secretariat decided to add this bacterium to the Alert List.



Very little information is available in the literature about the world distribution of C. flaccumfaciens pv. poinsettiae, and most records are now quite old and could not be confirmed by more recent publications. Therefore, the list below is only indicative and may not reflect the present situation of the bacterium in the listed countries.
EPPO region: Transient. 
The bacterium has occasionally been reported from several countries. In the United Kingdom, it was isolated in 1984 but not reported since then. In Slovenia, it was detected in 2008 in a nursery on plant material which had been imported from Germany but has not been detected again. In Germany, it has occasionally been found in glasshouse nurseries but eradication measures have been applied in all cases (outbreaks detected in 2014 in North Rhine-Westphalia; and in 2016 in Lower Saxony and Baden-Württemberg have all been eradicated – an outbreak detected in 2018 in Schleswig-Holstein remains under eradication) .
North America: USA (Alabama, California, Florida, Hawaii, Maryland, Nebraska, New Jersey, New York, North Dakota, Pennsylvania).
South America: Venezuela.
Oceania: New Zealand (North Island).


On which plants

Poinsettia (Euphorbia pulcherrima) is the only known natural host.



The early symptoms are water soaked stripes on green stems which can spread to leaf-stalks and leaves. Leaf spots, defoliation, and brown discoloration of the vascular tissues are also observed. Golden brown liquid may drip from broken stems and leaf lesions. Severe infections lead to longitudinal fissures in the leaf-stalks. Cuttings from infected plants may develop poorly or fail completely. Data on the biology of this bacterium is generally lacking but the severity of the disease can be favoured by warm temperatures, moist conditions, and high nitrogen inputs. Latent infections can occur. No information is available on quantitative yield losses but it is reported that the disease may result in severe damage.



The disease is spread by infected cuttings, and probably by water splashes (e.g. with overhead irrigation), tools, and workers. Over long distances, the trade of infected plants is probably the most important pathway to introduce and spread the disease.



Plants for planting (including cuttings) of E. pulcherrima from countries where the bacterium occurs.


Possible risks

Poinsettias are popular indoor plants in the EPPO region, commonly associated with Christmas. Although data is generally lacking on the economic impact of C. flaccumfaciens pv. poinsettiae on poinsettia crops, the disease is reported to cause damage and once introduced in a production system, no curative treatments are available. Disease control relies on the rapid destruction of infected plants, application of strict sanitation measures (e.g. disinfection of surfaces, tools) and the use of healthy planting material. It is also noted that, as plants may be latently infected, testing of mother plants before taking cuttings would help contain the disease. In 2014, both the Dutch and German PRAs concluded that C. flaccumfaciens pv. poinsettiae could present a risk to poinsettia production. In the Netherlands, the NPPO concluded that growers should be informed about these risks and the bacterium was included in the national survey for 2015. In Germany, eradication measures (destruction of infected plants, disinfection measures) were taken as soon as the bacterium was detected. The overall lack of information about C. flaccumfaciens pv. poinsettiae renders risk analysis difficult and highly incertain, but it seems wise that those involved in poinsettia production are made aware of this disease.


Benko Beloglavec A, Ličen R, Seljak G, Šnajder Kosi K, Grando Z, Lešnik, Pavlič Nikolič E (2009) [New pests detected on plants moved from member states of the European Union or during the production in Slovenia in 2008]. Proceedings of the 9th Slovenian Conference on Plant Protection (Nova Gorica, SI, 2009-03-04/05), 483-487 (in Slovene).
Bradbury JF (1991) Curtobacterium flaccumfaciens pv. poinsettiae. IMI Descriptions of Fungi and Bacteria No. 1045. Mycopathologia 115, 53–54.
CABI (2000) Curtobacterium flaccumfaciens pv. poinsettiae. Distribution Maps of Plant Diseases no. 550. CABI, Wallingford (GB), 2 pp.
INTERNET (last accessed 2017-01)
- Alabama A&M and Auburn Universities. Alabama Cooperative Extension System. Poinsettia diseases and their control. http://www.aces.edu/pubs/docs/A/ANR-1272/ANR-1272.pdf

- CABI Crop Protection Compendium. Basic datasheet Curtobacterium flaccumfaciens pv. poinsettiae. http://www.cabi.org/cpc/datasheet/15341

- JKI (2014-09-17) Express PRA for Curtobacterium flaccumfaciens pv. poinsettiae. http://pflanzengesundheit.jki.bund.de/dokumente/upload/43f1a_curtobacterium-flaccumfaciens-pv-poinsettiae_express-pra_en.pdf

- NPPO, the Netherlands (2014-12-18) Quick scan for Curtobacterium flaccumfaciens pv. poinsettiae. https://english.nvwa.nl/topics/pest-risk-analysis/documents/communicatie/diversen/archief/2016m/quickscan-curtobacterium-flaccumfaciens-pv-poinsettiae

- PennState Extension. Poinsettia diseases. http://extension.psu.edu/pests/plant-diseases/all-fact-sheets/poinsettia-diseases

- University of California. Agriculture & Natural Resources. UC-IPM. Floriculture and ornamental nurseries. Poinsettia. http://ipm.ucanr.edu/PMG/r280112511.html

- Widely Prevalent Bacteria of the United States. Curtobacterium flaccumfaciens pv. poinsettiae. https://www.prevalentbacteria.org/subject.cfm?id=56522

NPPO of Germany (2018-10, 2018-11, 2019-03).

McFadden LA (1959) Bacterial blight of poinsettia. Proceedings of the Florida State Horticultural Society 72, 392-394.
McFadden LA, Creager DB (1960) Recent occurrence of bacterial blight of poinsettia in Florida. Plant Disease Reporter 44(7), 568-571.
Pirone PP, Bender TR (1941) A new bacterial disease of poinsettia. N.J. Agric. Exp. Stn. Nursery Disease Notes 14, 13-16.
Starr MP, Pirone PP (1942) Phytomonas poinsettiae n. sp., the cause of a bacterial disease of poinsettia. Phytopathology 32(12), 1076-1081.
Trujillo GE, Gaskin D, Hernández J, Hernández Y (1989) The bacterial angular spot disease of poinsettia (Euphorbia pulcherrima Willd.) caused by Corynebacterium flaccumfaciens pv. poinsettiae. Revista de la Facultad de Agronomía, Universidad Central de Venezuela 15(3-4), 207-212.
Wehlburg C (1966) Bacterial leaf spot of poinsettia. Plant Pathology Circular no. 52. Florida Department of Agriculture. Division of Plant Industry. https://www.freshfromflorida.com/content/download/11058/142639/pp52.pdf


EPPO RS 2017/015, 2019/104

Entry date 2017-01