Sudden Oak Death in Washington State

1. Sudden Oak Death in Washington State

2. What is Sudden Oak Death? • First seen in early 1990s • Two types of symptoms • Canker • Foliar blight • Caused by Phytophthora ramorum (Oomycetes) • Over 70 plant hosts • Most of the outbreak in central coastal CA Dead tanoak in Muir Woods NP, CA Foliar symptoms on Rhododendron

3. Two distinct diseases caused byPhytophthora ramorum • Sudden Oak Death • Red oaks, beech, and tanoak • Stem lesions beneath the bark girdle and kill tree • Cankers often bleed or ooze • Can kill adult trees • “Dead end” hosts • P. ramorum foliar blight/Ramorum blight • Non-oak hosts • Spots and blotches on leaves & shoot die back • Can kill juvenile plants, usually not lethal for mature plants • Spreads the disease Slide from the USDA PRED Training Module

4. Phytophthora spore stages • Phytophthora thrives in wet conditions • P. ramorum infections initiated by sporangia and zoospores • Chlamydospores can persist in soil and leaf litter • Sexual oospores are resistant to damage Sporangia containing swimming zoospores Chlamydospores Oospores (P. infestans)

5. How P. ramorum spreads • Water - Wind-driven rain, irrigation, runoff • Humans – soil on hiker’s boots and bicycle tires, nursery plants • Wildlife

6. P. ramorum genetics • Two mating types – A1 and A2 • Three clonal lineages – NA1, NA2, EU1 NA1 and NA2 All A2 EU1 Mostly A1, with a few A2 There is concern about NA and EU populations mating, but this has not been observed

7. P. ramorum in North American forests • SOD currently found in 14 CA counties and 1 OR county • These counties are under quarantine • SOD not known to be established anywhere else in N.A. forests Map from www.suddenoakdeath.org Kelly, UC-Berkeley Slide from the USDA PRED Training Module

8. Sudden Oak Death in California • Tanoak (Lithocarpus densiflorus) and oak species affected • Tree death primarily along urban-wildland interface • Dying trees created hazards for residents • Increased fire hazard in wildland areas from dead trees Photo: Marin County Fire Department

9. Infested area quarantined and eradication attempted • 2001-2004: infested area decreased or remained the same • 2005-present: infested area increasing • Area under quarantine now 166 sq miles SOD in Oregon Photo: Everett Hansen, Oregon State University

10. Risk Group III Risk Group II Risk Group I Risk of sudden oak death based on P. ramorum climate matching and hardwood forest density in the USA (High) Fowler, G., Magarey, R., Colunga, M. 2006. Climate-host mapping of Phytophthora ramorum, causal agent of sudden oak death In: Frankel, Susan J.; Shea, Patrick J.; and Haverty, Michael I., tech. coords. Proceedings of the sudden oak death second science symposium: the state of our knowledge. Gen. Tech. Rep. PSW-GTR-196. Albany, CA: Pacific Southwest Research Station, Forest Service, U.S. Department of Agriculture: 329-332

11. P. ramorum in European forests Rhododendron ponticum Red Oak: Quercus rubra These species used as ornamentals in WA Beech: Fagus sylvatica Photo: DEFRA Slide from the USDA PRED Training Module

12. SOD Risk

13. Nursery 2002 0 2003 1 2004 25 2005 16 2006 12 2007 7 2008 4 Forest and stream 2002 --- 2003 --- 2004 --- 2005 0 2006 2 2007 6 2008 6 Washington P. ramorum surveys

14. What happens when P. ramorum is detected in a nursery

15. Summary of P. ramorum in Washington • Found in nursery stock, not thought to be established • in natural or urban landscape • APHIS and WSDA conduct annual • surveys to inspect production nurseries • DNR conducts stream baiting and forest surveys • Many plants native to Washington are • known hosts • Potential for impact on native ecosystem • Quarantines may be imposed if detected in landscape Slide by Norm Dart

16. Recognizing Symptoms • Sudden Oak Death of oaks • Ramorum blight of other hosts • Key to determine if samples should be submitted for P. ramorum testing in Washington • focus on recently purchased (or near recently purchased) camellia, kalmia, lilac, pieris, rhododendron, or viburnum

17. Symptoms on trees P. cambivora on Beech • Bleeding cankers • Cankers can girdle the tree and kill it • Host species in Fagaceae: oaks, beech, tanoak • Other Phytophthora spp can cause the same symptoms P. ramorum on Oak

18. Similar symptoms • Phytophthora root disease and canker • Armillaria root disease

19. Bacterial stem diseases • Bacterial wetwood • Bleeding stem cankers caused by Pseudomonas syringae

20. Important hosts of P. ramorum in WA nurseries • Rhododendron • Camellia • Viburnum • These genera account for over 90% of the positive finds in Washington nurseries • Others – • Pieris • Kalmia

21. Rhododendron Shoot blight Leaf blotch on pacific rhododendron caused by Phytophthora ramorum. Photo by Oregon Department of Forestry.

22. P. ramorum symptoms on native rhododendron Shoot dieback Foliar blight Foliar blight Rhododendron macrophyllum Photo: Everett Hansen, Oregon State University Slide from the USDA PRED Training Module

23. Root rot of rhododendron Phytophthora root rot - not caused by P. ramorum Slide from the USDA PRED Training Module Photo: Jay Pscheidt, Oregon State University

24. Leaf necrosis of Rhododendron Sun scorch, lesion does not extend down leaf midrib Gray blight can develop on sun scorched Rhododendron leaves Photo: Rich Regan, Oregon State University

25. P. ramorum on Camellia Brown lesions: irregular and restricted to leaf tip Photos: Oregon Dept. of Agriculture & Cheryl Blomquist, CDFA Slide from the USDA PRED Training Module

26. Symptoms on camellia • Look for lower leaves that have fallen off Photo: Cheryl Blomquist, CDFA

27. Sun Scorch of Camellia Brown spot not extending along petiole or midrib of leaf Slide by Norm Dart

28. Viburnum V. plicatum “Mariesii” Viburnum tinus “Spring Bouquet” V. davidii

29. Symptoms Grey mold • Stem canker • Foliage and shoot blight Botrytis P. ramorum

30. Some other hosts Grand fir Bigleaf maple Pacific madrone Lilac

31. Should an infected plant be submitted for laboratory analysis? • Plants likely to be infected by Phytophthora ramorum - Rhododendron, Camellia, and Viburnum • Affected plant is on host list and purchased since 2002, • Affected plant is near a recently purchased host plant • Symptoms are consistent with Phytophthora ramorum: • Brown leaf spots with diffuse margins • Shoot tip dieback

32. Sample referral and submission • In Washington state Master Gardeners and Extension Agents are asked to submit suspect samples to the WSU Puyallup Plant Clinic • If you determine a sample should be submitted • Download and fill out plant clinic sample form and follow approved procedures http://www.puyallup.wsu.edu/plantclinic/samples.htss.html • Please consult the plant clinic before sending samples

33. For more information please visit the WSU P. ramorum education webpage: http://www.puyallup.wsu.edu/ppo/sod.html You may also call the WSU Plant Diagnostic Lab at (253) 445-4582 with additional questions relating to P. ramorum diagnostics or if you would like to have a plant tested. Slide by Norm Dart