Global invasive species database

  • General
  • Distribution
  • Impact
  • Management
  • Bibliography
  • Contact
Common name
sudden oak death (English), SOD (English), maladie de l�encre des ch�nes rouges (French), ramorum dieback (English), ramorum leaf blight (English), ramorum blight (English), mort subite du ch�ne (French)
Synonym
Similar species
Phytophthora cinnamomi, Phytophthora lateralis, Phytophthora nemorosa
Summary
Until 2000, Phytophthora ramorum, the causal agent of Sudden Oak Death, was undiscovered and unnamed. This water mould or oomycete is the cause of much concern in North America and Europe due to three factors: (i) the high level of local destruction it causes in California, (ii) the lack of knowledge of its epidemiology (due to its recent discovery), and (iii) its high prevalence in nurseries (which increases the potential of spread to a new location and/or country). The oomycete has an extensive host range, covering many plant genera and several families and including treees and shrubs and woody and herbaceous perennials. Phytophthora ramorum causes canker development, shoot drooping and leaf blight. Spores spread to new locations mainly by the nursery trade and are spread locally by vectors: soil, water and articles associated with humans.
Species Description
Morphology: In culture hyphae are highly branched, contorted and dendritic. Chlamydospores, produced on hyphal tips, are at first hyaline, then darken to cinnamon brown, 30-90 µm. Sporangia (a particularly diagnostic characteristic) are oval-shaped, semi-papillate, 30-90 µm, and deciduous. Oospores have not been observed.

Disease symptoms: While most temperate-climate members of the Oomycota genus Phytophthora are root-infesting, soil and water-bourne organisms, P. ramorum spreads mostly aerially and generally infests trees and plants above the soil line (including leaves, shoots, woody stems and bark). Infections on the bark develop into cankers, which produce a red/brown/black sappy exudate (a symptom referred to as \"bleeding\"). Cankers can occur on the trunk at the root crown up to 20m above the ground, but do not enlarge below the soil line into the roots. Individual cankers are delimited by thin black lines in the inner bark and can be over 2m in length. Aerial seeps not connected to the root collar are a good indication that a tree is infected by P. ramorum (other Phytophthora can cause identical seeps linked to root infections). Infections on the leaves cause spotting and browning. Infections on the twigs cause branch drooping and dieback (ANR, 2003; Garbelotto, 2004; Rizzo et al., 2002b).

Please see PaDIL (Pests and Diseases Image Library) Species Content Page Fungi: Sudden oak death \r\n for high quality diagnostic and overview images.

Notes
Publications, management guidelines and educational resources can be assessed from:
ANR, 2003. Marin County UCCE. Sudden Oak Death: Publications.
Pdfs on a wide range of topics including the biology, genetics and management of SOD can be assessed from:
UC Berkeley, 2004. Sudden Oak Death Science Symposium
Lifecycle Stages
The oomycete develops sporangia, which hold and produce zoospores and which can be airborne. The sporangium releases zoospores once it has landed on a suitable host surface. The leaves and twigs of susceptible hosts are readily colonised by zoospores. A water film and/or warm temperatures (around 18–20°C) facilitate infection. Leaves and twigs then develop black lesions (which spread to branches in some species, causing dieback). In conditions of high humidity (close to 100%) and moderate temperature, new sporangia and resting round structures (chlamydospores) will be produced on the lesions in approximately 48 hours. Infectious propagules accumulate in the soil beneath the plant in water bodies. In the final disease phase, the main stems of tanoaks and oaks may be infected. The pathogen preferentially colonises the sugar-rich phloem of the host, only marginally colonising the outer bark and xylem. As a result of phloem colonisation a canker develops under the bark, and sappy exudates will flow outside the bark. In tanoaks multiple cankers often occur on tanoaks at different heights (thought to be caused by sporangia produced on leaves of the infected host tanoak or on the leaves of adjacent infected hosts). On the less susceptible coast live oaks cankers normally only occur near the soil line (presumably caused by the accumulation of sporangia from the leaves of adjacent infected hosts). As oak leaves are rarely colonised by P. ramorum re-infection from the host tree is not likely. This is why infection in oaks is epidemiologiclly linked to, and depends on, the presence of adjacent infected foliar hosts (such as bay laurel). If girdling occurs the irreversible death process is started (although it may take a year or more for browning of the tree's crown to occur). Girdling leads to the establishment of secondary organisms and opportunistic pathogens (such as wood decay fungi and canker rots) (Garbello, 2004).
Habitat Description
Reports from the USA suggest the pathogen has an optimum growth temperature of 20°C, there is no mycelial growth at greater that 30°C or at less than 2°C (Sansford, Jones and Brasier, 2003). Areas with wet climates and constant mild temperatures, resembling the central California coast are optimal to disease developement. Most sporangia production occurs during the rainy season (Garbelotto, 2004).\r\n
In North America forests of three main types are affected: mixed evergreen-bay-arbutus (dry open forest with grass and dense shrub understory), Tanoak-Douglas-fir (wet forest, often has a Vaccinium understory), Coast Redwood (open forest, often has a tanoak understory). In Europe the pathogen is mainly a pest species of Rhododendron and Viburnum. European countries where Rhododendron is affected have cool to cold winters with rain throughout the year. The pathogen therefore may be capable of establishment in other northern areas or some southern coastal Atlantic/Mediterranean areas in Europe. (The pattern of Rhododendron distribution may, however, reflect the movement of the infected stock) (Sansford, Jones and Brasier, 2003).

P. ramorum infects: \r\ntanoak (Lithocarpus densiflorus), coast live oak (Quercus agrifolia), black oak (Quercus kelloggii), Pacific huckleberry / evergreen huckleberry (Vaccinium ovatum), rhododendron and azalea species (Rhododendron), maple species (Acer), manzanita species (Arctostaphylos), Pacific madrone (Arbutus menziesii), California buckeye (Aesculus californica), California bay laurel (Umbellularia californica), California honeysuckle (Lonicera hispidula), toyon / Christmasberry (Heteromeles arbutifolia), California coffeeberry (Rhamnus californica), coast redwood (Sequoia sempervirens), Douglas-fir (Pseudotsuga menziesii), Western star flower (Trientalis latifolia), hybrid viburnum (Viburnum bodnantense) (only in cultivation), Pieris spp. (only in cultivation), Camellia spp. (only in cultivation).
For an updated list of plants reported (or suspected) to be susceptible to P. ramorum please see: \r\nPPQ, 2004. List of Hosts and Plants Associated with Phytophthora ramorum
Reproduction
Phytophthora ramorum produces large amounts of asexual infectious swimming propagules (zoospores) in oval-shaped sporangia, as well as producing hard, round, resting propagules (chlamydospores). To complete its sexual cycle P. ramorum requires individuals bearing two mating types (A1 and A2). In nature in North America only A2 individuals have been reported, while - with a single exception - only A1 have been reported from nursery or nursery-linked infections in Europe (as of April 2004) (Garbelotto, 2004).
Pathway
In the case of Europe interregional transport of the disease appears to have already occurred due through the trading and sales of ornamental plants (Garbelotto, 2004). Infected plants have been found in nurseries in Europe and the USA. P. ramorum could be spread to new countries by the nursery trade.
The combined microsatellite, sequencing and morphological analyses by Ivors et al. (2006) suggest the 151 isolates analysed clustered in three clades, represent distinct evolutionary lineages. All three clades were identified in some US nurseries, emphasizing the role of commercial plant trade in the movement of this pathogen. Movement of contaminated soil (or other habitat material) may spread the pathogen. The leaves of susceptible hosts may become infected when splashed with infected soil (Garbelotto, 2004). How P. ramorum originally entered Europe and the USA is unknown, but the seperate clades (a clade is defined as a group of species that share a common ancestor, which is not shared by another species outside of the clade) are of different mating types (A1 and A2 respectively) and appear to be from distinct genetic lineages, suggesting the pathogen is from a third location (with both mating types and representations of both lineages) (Garbelotto, 2004).

Principal source: Sansford, Jones and Brasier, 2003. Pest Risk Analysis: Phytopthora ramorum.
Garbelotto, 2004. Sudden Oak Death: A Tale of Two Continents.

Compiler: National Biological Information Infrastructure (NBII) & IUCN/SSC Invasive Species Specialist Group (ISSG)

Review: Anon

Publication date: 2008-05-28

Recommended citation: Global Invasive Species Database (2016) Species profile: Phytophthora ramorum. Downloaded from http://www.iucngisd.org/gisd/species.php?sc=563 on 31-08-2016.

General Impacts
There are two categories of hosts for Phytophthora ramorum, each of which are susceptible to the pathogen in different organs: bark canker hosts and foliar hosts. Bark canker hosts become infected on their trunks. In highly susceptible species (tanoaks and to a lesser extent oaks) cankers eventually girdle the tree, resulting in starvation and death. Mortality may occur in as short a timespan as two years. Foliar hosts become infected on their leaves and twigs. Leaf infection is accompanied by branch infections and branch dieback in some foliar hosts (for example, rhododendrons, Pacific madrone, Pacific huckleberry and Toyon / Christmasberry); in other foliar hosts only leaves are affected (for example, bay laurel, maples and buckeye). Foliar hosts only occaasionally die from infection. (Tanoaks belong to both host categories as they may develop bark and/or foliar infections. Foliar infections are common in young tanoaks and result in leaf blight and the killing of the plant from the \"top down\") (ANR, 2003; Garbelotto, 2004).
Many plants within the host range of the oomycete are grown for economic gain or have environmental or social valued. Tanoak, coast live oak and black oak in USA hardwood forests infected with the oomycete die in a short period of time following the onset of symptoms. Oak plays an important role in European natural ecosystems, especially forest and savanna-woodland ecosystems. It can be found in parks and open countrysides. It has been estimated that there are about 200 million oak trees in the UK and their loss from could have a major impact on soil erosion, hydrology, sedimentation in rivers in certain areas. Other possible effects include loss of associated organisms (biodiversity) and a negative impact on tourism, cultural history and local woodland economies (Braisier, 2000a, unpub., in Sansford, Jones and Brasier, 2003).
Management Info
Preventative measures: Preventing the introduction of Phytophthora ramorum into new areas should be the first priority when managing Sudden Oak Death (SOD). This entails identifying the likely sources of infection. In order of importance these sources are live plants (especially those supporting sporulation), green waste, soil and water, debarked untreated wood, entire logs and firewood. Quarantine and sanitation measures for nursery plants, wood products and soil associated with infestation sites should be employed to prevent both long and short distance spread. \r\n

Drenth et al. 2006 describe the development and validation of a DNA-based diagnostic assay that can detect and identify 27 different Phytophthora species. Belbahri et al (2007) report that the \"new specific hybridization probes for a real-time PCR amplification method\" they developed for early detection of P. ramorum is found to be rapid, robust and labour-saving, and has proved suitable for routine use in a molecular diagnostic laboratory.

Please follow this link managing Phytophthora ramorum for detailed management options.

Countries (or multi-country features) with distribution records for Phytophthora ramorum
NATIVE RANGE
Informations on Phytophthora ramorum has been recorded for the following locations. Click on the name for additional informations.
Lorem Ipsum
Location Status Invasiveness Occurrence Source
Details of Phytophthora ramorum in information
Status
Invasiveness
Arrival date
Occurrence
Source
Introduction
Species notes for this location
Location note
Management notes for this location
Impact
Mechanism:
Outcome:
Ecosystem services:
Impact information
There are two categories of hosts for Phytophthora ramorum, each of which are susceptible to the pathogen in different organs: bark canker hosts and foliar hosts. Bark canker hosts become infected on their trunks. In highly susceptible species (tanoaks and to a lesser extent oaks) cankers eventually girdle the tree, resulting in starvation and death. Mortality may occur in as short a timespan as two years. Foliar hosts become infected on their leaves and twigs. Leaf infection is accompanied by branch infections and branch dieback in some foliar hosts (for example, rhododendrons, Pacific madrone, Pacific huckleberry and Toyon / Christmasberry); in other foliar hosts only leaves are affected (for example, bay laurel, maples and buckeye). Foliar hosts only occaasionally die from infection. (Tanoaks belong to both host categories as they may develop bark and/or foliar infections. Foliar infections are common in young tanoaks and result in leaf blight and the killing of the plant from the \"top down\") (ANR, 2003; Garbelotto, 2004).
Many plants within the host range of the oomycete are grown for economic gain or have environmental or social valued. Tanoak, coast live oak and black oak in USA hardwood forests infected with the oomycete die in a short period of time following the onset of symptoms. Oak plays an important role in European natural ecosystems, especially forest and savanna-woodland ecosystems. It can be found in parks and open countrysides. It has been estimated that there are about 200 million oak trees in the UK and their loss from could have a major impact on soil erosion, hydrology, sedimentation in rivers in certain areas. Other possible effects include loss of associated organisms (biodiversity) and a negative impact on tourism, cultural history and local woodland economies (Braisier, 2000a, unpub., in Sansford, Jones and Brasier, 2003).
Red List assessed species 0:
Locations
Europe
FRANCE
UNITED KINGDOM
UNITED STATES
Mechanism
[5] Parasitism
Outcomes
[9] Socio-Economic
  • [3] Damage to agriculture
  • [5] Damage to forestry
  • [1] Damage to ornamentals
Management information
Preventative measures: Preventing the introduction of Phytophthora ramorum into new areas should be the first priority when managing Sudden Oak Death (SOD). This entails identifying the likely sources of infection. In order of importance these sources are live plants (especially those supporting sporulation), green waste, soil and water, debarked untreated wood, entire logs and firewood. Quarantine and sanitation measures for nursery plants, wood products and soil associated with infestation sites should be employed to prevent both long and short distance spread. \r\n

Drenth et al. 2006 describe the development and validation of a DNA-based diagnostic assay that can detect and identify 27 different Phytophthora species. Belbahri et al (2007) report that the \"new specific hybridization probes for a real-time PCR amplification method\" they developed for early detection of P. ramorum is found to be rapid, robust and labour-saving, and has proved suitable for routine use in a molecular diagnostic laboratory.

Please follow this link managing Phytophthora ramorum for detailed management options.

Locations
Management Category
Prevention
Eradication
Control
None
Bibliography
48 references found for Phytophthora ramorum

Managment information
Belbahri, L., G. Calmin, S. Wagner, E. Moralejo, S. Woodward and F. Lefort., 2007. Specific hybridization real-time PCR probes for Phytophthora ramorum detection and diagnosis. Forest Pathology Volume 37, Issue 6, December 2007 pages 403�408
Garbelotto, M. 2004. Sudden Oak Death: A Tale of Two Continents, Outlooks on Pest Management: 85 - 89.
Summary: Available from: http://cemarin.ucdavis.edu/pdf%20files/PesticideOutlook.pdf [Accessed 12 January 2005]
Ivors, K., Garbelotto, M., Vries, I. D. E., Ruyter-Spira, C., Hekkert, B. Te., Rosenzweig, N. & Bonants, P., 2006. Microsatellite markers identify three lineages of Phytophthora ramorum in US nurseries, yet single lineages in US forest and European nursery populations. Molecular Ecology 15 (6), 1493-1505
Liberato J.R, O�Brien J.G & Werres S 2006. Sudden oak death (Phytophthora ramorum) Pest and Diseases Image Library. Updated on 5/10/2006 12:24:14 PM.
Summary: Available from: http://www.padil.gov.au/pests-and-diseases/Pest/Main/136615 [Accessed 7 December 2011]
Manter, D. K., Karchesy, J. J. & Kelsey, R. G., 2006. The sporicidal activity of yellow-cedar heartwood, essential oil and wood constituents towards Phytophthora ramorum in culture. Forest Pathology 36 (5), 297-308.
NIDirect, 2011. Preventing the spread of tree disease
Summary: Available from: http://www.nidirect.gov.uk/index/information-and-services/leisure-home-and-community/leisure-and-recreation/outdoor-recreation/preventing-the-spread-of-tree-disease.htm [Accessed September 2 2011]
Swain, S., Harnik, T., Mejia-Chang, M., Hayden, K., Bakx, W., Creque, J. & Garbelotto, M. 2006. Composting is an effective treatment option for sanitization of Phytophthora ramorum-infected plant material. Journal of Applied Microbiology 101 (4), 815-827.
United States Government Accountability Office (GAO) GAO-06-353 Report, April 21, 2006. Invasive Forest Pests: Lessons Learned from Three Recent Infestations May Aid in Managing Future Efforts.
Summary: Invasive forest pests have seriously harmed our environment and imposed significant costs upon our economy. The U.S. Department of Agriculture (USDA) is the lead agency for responding to forest pests. This report evaluates the federal response to three invasive forest pests�the Asian longhorned beetle, the emerald ash borer, and the pathogen Phytophthora ramorum (P. ramorum).Specifically, GAO describes (1) the status of efforts to eradicate these species, (2) the factors affecting the success of those efforts, (3) overall forest health monitoring programs, (4) coordination and communication of the three pest response efforts, and (5) USDA�s use of panels of scientific experts to aid in the response efforts.
Available from: http://www.gao.gov/new.items/d06353.pdf [Accessed 20 May 2006]
General information
Aldhous, J.R. 2004. Phytophthora ramorum - The current position of Ramorum Dieback Disease and Sudden Oak Death Disease. Scottish Forestry. 58(1). 3, 5-7.
Cree, L.A. 2001. Pest fact sheet: Phytophthora ramorum. Canadian Food Inspection Agency.
Summary: This fact sheet details the identification, life history, distribution, and control measures for the species in California and Oregon.
Available from: http://www.inspection.gc.ca/english/plaveg/protect/facren/sodfacte.pdf
Davidson, J. M., Garbelotto, M., Koike, S. T and Rizzo, D. M. 2002. First report of Phytophthora ramorum on Douglas-fir in California. Plant Disease. 86(11). 1274.
De Merlier, D., Chandelier, A and Cavelier, M. 2003. First report of Phytophthora ramorum on Viburnum bodnantense in Belgium. Plant Disease. 87(2). 203.
Department for Environment, Food and Rural Affairs (DEFRA), United Kingdom. Fact Sheet.
Summary: Fact sheet with a general description of infested trees, methods of spread, and distribution.
Available from: http://www.defra.gov.uk/planth/pramorum.htm
Hansen, E.M., Reeser, P.W., Davidson, J.M., Garbelotto, M., Ivors, K., Douhan, L. and Rizzo, D.M. 2003a. Phytophthora nemorosa, a new species causing cankers and leaf blight of forest trees in California and Oregon, USA, Mycotaxon 88: 129 - 138.
Hansen, E. M., Reeser, P. W., Davidson, J. M., Garbelotto, M., Ivors, K., Douhan, L and Rizzo, D. M. 2003. Phytophthora nemorosa, a new species causing cankers and leaf blight of forest trees in California and Oregon, U.S.A. Mycotaxon. 2003. 129-138.
Hansen, E.M., Reeser, P.W., Sutton, W., Winton, L.M and Osterbauer, N. 2003b. First report of A1 mating type of Phytophthora ramorum in North America, Plant Disease 87(10): 1267.
Hansen, E. M., Reeser, P. W., Sutton, W., Winton, L. M and Osterbauer, N. 2003. First report of A1 mating type of Phytophthora ramorum in North America. Plant Disease. 87(10). 1267.
Huberli, D., Reuther, K. D., Smith, A., Swain, S., Tse, J. G and Garbelotto, M. 2004. First report of foliar infection of Rosa gymnocarpa by Phytophthora ramorum. Plant Disease. 88(4). 430.
Huberli, D., Van Sant-Glass, W., Tse, J. G and Garbelotto, M. 2003. First report of foliar infection of starflower by Phytophthora ramorum. Plant Disease. 87(5). 599.
Inman, A. J., Townend, V. C., Barnes, A. V., Lane, C. R., Hughes, K. J. D., Griffin, R. L and Eales, S. J. 2003. First report of ramorum dieback (Phytophthora ramorum) on Pieris in England. Plant Pathology (Oxford). 52(6). 785.
Kroon, Laurens P. N. M., Verstappen, Els C. P., Kox, Linda F. F., Flier, Wilbert G and Bonants, Peter J. M. 2004. A rapid diagnostic test to distinguish between American and European Populations of Phytophthora ramorum. Phytopathology. 94(6). 613-620.
Lane, C. R., Beales, P. A., Hughes, K. J. D., Griffin, R. L., Munro, D., Brasier, C. M and Webber, J. F. 2003. First outbreak of Phytophthora ramorum in England, on Viburnum tinus. Plant Pathology (Oxford). 52(3). 414.
Martin, Frank N., Tooley, Paul W and Blomquist, Cheryl. 2004. Molecular detection of Phytophthora ramorum, the causal agent of sudden oak death in california, and two additional species commonly recovered from diseased plant material. Phytopathology. 94(6). 621-631.
Murphy, S. K and Rizzo, D. M. 2003. First report of Phytophthora ramorum on canyon live oak in California. Plant Disease. 87(3). 315.
Orlikowski, Leszek B. 2003. Development and spread of Phytophthora ramorum in the presence of grapefruit extract. Journal of Plant Protection Research. 43(3). 213-218.
Plant Health, DEFRA/Forestry Commission. 2002 News Release.
Summary: News release and FAQ about the incidence of the American strain of sudden oak death in England nurseries.
Available from: http://www.defra.gov.uk/news/2002/020503bquanda.htm
Rizzo, D. M., Garbelotto, M., Davidson, J. M., Slaughter, G. W and Koike, S. T. 2002. Phytophthora ramorum as the cause of extensive mortality of Quercus spp. and Lithocarpus densiflorus in California. Plant Disease. 86(3). 205-214.
Slawson, D. 2003. Phytophthora ramorum - Situation in the UK and EU
Summary: Available from: http://www.defra.gov.uk/planth/phnews/ukandeu.pdf [Accessed 12 January 2005]
Themann, Karin., Werres, Sabine., Luettmann, R and Diener, H. A. 2002. Observations of Phytophthora spp. in water recirculation systems in commercial hardy ornamental nursery stock. European Journal of Plant Pathology. 108(4). 337-343
Varela, C. Pintos., Vazquez, J. P. Mansilla and Casal, O. Aguin. 2003. First report of Phytophthora ramorum on Camellia japonica in Spain. Plant Disease. 87(11). 1396.
Werres, Sabine and De Merlier, Daphne. 2003. First detection of Phytophthora ramorum mating type A2 in Europe. Plant Disease. 87(10). 1266.
Werres, Sabine., Marwitz, Rainer., Man in t Veld, Willem A., De Cock, Arthur W. A. M., Bonants, Peter J. M., De Weerdt, Marjanne., Themann, Karin., Ilieva, Elena and Baayen, Robert P. 2001. Phytophthora ramorum spp. nov., a new pathogen on Rhododendron andBurnum. Mycological Research. 105(10). 1155-1165.
Werres S., Marwitz R., Man in �t Veld W.A., De Cock A.W.A.M., Bonants P.J.M., De Weerdt M., Themann K., Ilieva E. und R.P. Baayen (2001): Phytophthora ramorum sp. nov., a new pathogen on Rhododendron and Viburnum. Mycological Research 105 (10), 1155-1165.
Contact
The following 0 contacts offer information an advice on Phytophthora ramorum