Sudden oak death
- Latin : Phytophthora ramorum Werres, De Cock & Man in't Veld.
- English: Sudden oak death
- French: Encre des chênes rouges
Synonyms: Ramorum blight; Ramorum bleeding canker; Ramorum shoot dieback. French names: encre des chênes rouges; la mort subite/soudaine du chêne
This disease is dealt with in a number of Canadian Food Inspection Agency directives:
- D-95-26: Phytosanitary requirements for soil and related matter, alone or in association with plants
- D-96-20: Canadian Growing Media Program (CGMP), Prior Approval Process and Import Requirements for Plants Rooted in Approved Media
- D-98-08: Entry Requirements for Wood Packaging Materials Produced in All Areas Other than the Continental United States
- D-01-01: Phytosanitary Requirements to Prevent the Entry and Spread of Phytophthora ramorum
- D-01-03: Plant Protection Requirements for Importations of Houseplants Intended for Personal Use from the Continental United States (US) and Hawaii.
- D-01-12: Phytosanitary Requirements for the Importation and Domestic Movement of Firewood
- D-02-02: Plant Protection Import Requirements for Rooted, or Unrooted Plants, Plant Parts, and Plants In Vitro for Planting
- D-02-12: Import requirements of non-manufactured wood and other non-propagative wood products, except solid wood packaging material, from all areas other than the continental United States
- D-03-05: Plant Protection Phytosanitary Import Requirements for Oak (Quercus spp.) Nursery Stock From Sources Outside of the Continental United States
In Canada, P. ramorum was found for the first time in 2003 in a wholesale nursery on the West Coast, and additional detections were made at four retail facilities. Eradication efforts are currently under way. This pathogen presents a medium risk for south-coastal British Columbia and a low risk for the other parts of British Columbia, south of Ontario and Quebec and the Maritime Provinces (Kristjansson and Miller 2009). The disease is well established on the west coast of the United States.
1. Mechanical and silvicultural
Eradication treatments have been carried out at affected sites (disease centres) in forest stands on the west coast of the United States. This approach involves cutting and burning all infected plants and all known host vegetation on the infested site. In addition, surveys are conducted to detect the pathogen within a 3-kilometre radius around infected sites. Tanoak (Lithocarpus densiflorus) stumps are sprayed with herbicides to prevent sprouting by this highly susceptible host (Goheen et al. 2007). According to Sinclair and Lyon (2005), eradication treatments have been completed at every infested site identified outside the main disease centres. The USDA Animal and Plant Health Inspection Service evaluates the possibility of eradication by taking into account the size and history of affected areas (Anonymous 2005).
The California Oak Mortality Task Force (2004) has provided various recommendations for preventing the spread of the disease.It is recommended that harvesting not be carried out in infested areas. In case of doubt, the officials in charge should err on the side of caution by considering that the area could be infected.
• Avoid carrying out work in muddy, wet areas and during rainy weather.
• Conduct operations during the dry season and drive trucks on paved surfaces.
• Inspect equipment before it is moved out of infested areas and remove all host plant debris.
• Locate landings away from infested areas.
• Regulate the transport of wood with reference to infested areas.
• When harvesting operations are over, wash all machinery to remove potentially contaminated mud and debris.
• A bleach solution or Lysol can be used to clean workers' boots and shoes.
Well controlled composting processes can destroy the causal organism (Swain et al. 2006).
Products registered in Canada for the control of P. ramorum contain the following active ingredients: metalaxyl-M and metalaxyl-S fosetyl-Al, or dimethomorph. Moreover, the active ingredient etridiazole is registered for the control of Phytophthora spp. in greenhouse. Metam sodium can be used to treat soil infected by Phytophthora spp.
These products are used mainly in horticultural operations or on ornamental plants. The combination of metalaxyl-M and metalaxyl-S appears to be more effective than fosetyl-Al, based on the studies by Heungens et al. (2005) and Chastagner et al. (2007).
There are many different chemical pest control products available. They may be toxic to plants, animals, humans or the environment in general. A number of these products pose potentially lethal risks to humans. To protect human health and the environment from pesticide-related risks, Canada adopted the Pest Control Products Act (PCPA). The Pest Management Regulatory Agency (PMRA; http://www.hc-sc.gc.ca/ahc-asc/branch-dirgen/pmra-arla/index-eng.php) is responsible for administering the Act. The pesticide label indicates the class designation (domestic, commercial, agricultural), the potential risks to human health and the environment, and the conditions and restrictions pertaining to product use. Compliance with the label directions and restrictions is mandatory. The provinces may also regulate the use of pesticides within their respective territory. For more information, consult the PMRA database at the following address: http://pr-rp.pmra-arla.gc.ca/portal/page?_pageid=34,17551&_dad=portal&_schema=PORTAL
In Canada, the K61 strain of Streptomyces sp. is registered against Phytophthora spp. on ornamental plants in greenhouse. The strain QST 713 of Bacillus subtilis is registered against these pathogens on ornamental plants in greenhouse and in field treatments
4. Genetic resistance
Phytophthora ramorum has such a large host range (ACIA 2009), encompassing more than 69 genera (Mignault 2007), that selecting disease-resistant trees does not appear as a potential option.
5. Stages in an integrated disease management program
Integrated management in horticultural nurseries is based on the recommendations of the Canadian Food Inspection Agency, particularly the directives related to imports of plant material, soil and wood, as well as the eradication protocols for propagation nurseries and retail nurseries (ACIA 2008a, b). In the western U.S. States between 2004 and 2006, successful results were obtained, with 50% fewer nurseries reported as being infested, as a result of the co-operation between stakeholders, the federal legislation implemented in 2005 and the introduction of best management practices (Suslow 2007).
Integrated disease management in forests is organized around the following:
- Surveys must be conducted to delimit areas in which the disease is present.
- In these areas, all infected trees and all host species are cut and burned, and stump sprouts are killed with herbicides and burned (Rioux 2007). This work must be done during dry weather and the necessary disinfection measures implemented.
- Host species located within a buffer zone around all infected plants, including the outermost symptomatic plant, must be destroyed the same way as infected vegetation. The width of the buffer zone has been increased from 30 to 100 m (Goheen et al. 2007).
- Quarantine rules pertaining to regulated areas have been established by regulatory authorities to minimize the spread of P. ramorum (Sinclair and Lyon 2005; Suslow 2007). Under quarantine rules, it is prohibited to move infected material outside a regulated area (Anonymous 2005).
- Treated areas are monitored to evaluate the success of the measures implemented.
- The Canadian Food Inspection Agency is currently developing a protocol for natural environments (Mignault 2007).
Disease management for ornamental trees must be handled by experts. Sudden oak death is a disease that falls under the Quarantine Act. The Canadian Food Inspection Agency is currently developing a protocol for landscaped residential and commercial sites infested by P. ramorum.
- [Anonymous]. 2005. Phytophthora ramorum APHIS Response Protocol for Forest and Wildland Environments. Internal report, 42 pp.
- Agence canadienne d’inspection des aliments (ACIA). 2008a. Protocole d’éradication visant les pépinières de multiplication infectées par le Phytophthora ramorum.35 pp. http://www.inspection.gc.ca/francais/plaveg/hort/pi-010f.pdf consulté le 23 janvier 2009.
- Agence canadienne d’inspection des aliments (ACIA). 2008b. Protocole d’éradication dans les pépinières de vente au détail infectées par le Phytophthora ramorum.28 pp. http://www.inspection.gc.ca/francais/plaveg/hort/pi-011f.pdf consulté le 23 janvier 2009.
- Agence canadienne d’inspection des aliments (ACIA). 2009. Phytophthora ramorum http://www.inspection.gc.ca/francais/plaveg/pestrava/phyram/sodmscf.shtml consulté en avril 2010.
- California Oak Mortaliy Task Force. 2004. Treatments. http://suddenoakdeath.org/html/treatments.html consulté le 19 janvier 2009.
- Chastagner, G. A.; DeBauw, A.; Riley, K. and Dart, N. 2007. Effectiveness of Fungicides in Protecting Conifers and Rhododendrons From Phytophthora ramorum. In : Frankel, Susan J.; John T. Kliejunas.; and Katharine M. Palmieri, tech. Coords. 2008. Proceedings of the Sudden Oak Death Third Science Symposium: March 5–9, 2007, Santa Rosa, California. Gen. Techn. Rep. PSW-GTR-214, Pacific Southwest Research Station, Forest Service. U.S. Department of Agriculture. Ccompact Disk.
- Goheen, E.M.; Everett Hansen, E.; Kanaskie, A.; Sutton, W. and Reeser, P. 2007. Vegetation Response Following Phytophthora ramorum Eradication Treatments in Southwest Oregon Forests. In Frankel, Susan J.; John T. Kliejunas.; and Katharine M. Palmieri, tech. Coords. 2008 Proceedings of the Sudden Oak Death Third Science Symposium: March 5–9, 2007, Santa Rosa, California. Gen. Techn. Rep. PSW-GTR-214, Pacific Southwest Research Station, Forest Service. U.S. Department of Agriculture. Format CD.
- Heungens, K.; De Dobbelaere, I. And Maes, M. 2005. In: Frankel, S.J.; Shea, P.J. and Haverty, M.I., tech. coords. 2006. Proceedings of the sudden oak death second science symposium : the state of our knowledge. 2005 January 18-21; Monterey, CA. Gen. Tech. Rep. PSW-GTR-196, Pacific Southwest Research Station, Forest Service. U.S. Department of Agriculture, 571pp.
- Kristjansson, G.T. et Miller, S.J. 2009. Pest risk assessment of Phytophthora ramorum Werres, de Cock & Man in't Veld causal agent of Ramorum blight, Ramorum bleeding canker, Ramorum (shoot) dieback and Sudden Oak Death. Canadian Food Inspection Agency, PRA 2000-39 Version 4. 251 pp.
- Mignault, M.-P. 2007. Phytophthora ramorum : Stratégie d’intervention en fonction du site d’introduction. In Agence canadienne d’inspection des aliments, formation sur les mesures d’urgence en protection des végétaux; formation des partenaires sur la maladie de l’encre du chêne rouge. Ste-Hyacinthe.
- Rioux, D. 2007 Phytophthora ramorum : Évaluation des risques phytosanitaires. In Agence canadienne d’inspection des aliments, formation sur les mesures d’urgence en protection des végétaux; formation des partenaires sur la maladie de l’encre du chêne rouge. Ste-Hyacinthe.
- Sinclair, W.A. and Lyon, H.H. 2005. Diseases of trees and shrubs - Second edition. Comstock Publishing Associates, Cornell University Press, Ithaca, New York, 660 pp.
- Swain, S., Harnik, T., Mejia-Chang, M., Hayden, K., Bakx, W., Creque, J. et Garbelotto, M. 2006. Composting is an effective treatment option for sanitization of Phytophthora ramorum-infected plant material. J. Appl. Microbiol. 101: 815-827.
- Suslow, K. 2007. Determining the Effectiveness of the Federal Order/Interim Rule on Phytophthora ramorum Dissemination in Nurseries. In Frankel, Susan J.; John T. Kliejunas.; and Katharine M. Palmieri, tech. Coords. 2008 Proceedings of the Sudden Oak Death Third Science Symposium: March 5–9, 2007, Santa Rosa, California. Gen. Techn. Rep. PSW-GTR-214, Pacific Southwest Research Station, Forest Service. U.S. Department of Agriculture. Format CD.
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