Transcript Sudden Oak Death in Washington State

Sudden Oak Death in
Washington State
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
Two distinct diseases caused by
Phytophthora ramorum
• Sudden Oak Death
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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
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)
How P. ramorum spreads
• Water - Winddriven rain,
irrigation, runoff
• Humans – soil on
hiker’s boots and
bicycle tires,
nursery plants
• Wildlife
P. ramorum genetics
• Two mating types – A1 and A2
• Three clonal lineages – NA1, NA2, EU1
NA1 and NA2
EU1
All A2
Mostly A1,
with a few A2
There is concern about NA and EU
populations mating, but this has not
been observed
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
Slide from the USDA PRED Training Module
Map from www.suddenoakdeath.org
Kelly, UC-Berkeley
Sudden Oak Death in California
Photo: Marin County Fire Department
 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
SOD in Oregon
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
Photo: Everett Hansen, Oregon State University
Risk of sudden oak death based on P. ramorum climate
matching and hardwood forest density in the USA
Risk Group III
Risk Group II
Risk Group I
(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
P. ramorum in
European forests
Rhododendron
ponticum
Beech: Fagus sylvatica
Slide from the USDA PRED Training Module
Red Oak:
Quercus rubra
These species used
as ornamentals in WA
Photo: DEFRA
SOD Risk
California and So. Oregon
Europe
WA and BC
Stem canker hosts a major
component of some forests
(Oaks and tanoaks)
Stem canker hosts in some
forests
Stem canker hosts mostly in
urban situations
Sporulating host present in
overstory (Bay laurel)
Sporulating host in
understory (Rhododendron)
Sporulating host – unknown
Present in nurseries
Present in nurseries
Present in nurseries
Suitable climate on coast
and in nurseries
Suitable climate, no dry
season
Suitable climate in western
portions of region
Heavy tree mortality in
some wildland areas
Washington P. ramorum surveys
Nursery
• 2002
• 2003
• 2004
• 2005
• 2006
• 2007
• 2008
0
1
25
16
12
7
4
Forest and stream
• 2002
--• 2003
--• 2004
--• 2005
0
• 2006
2
• 2007
6
• 2008
6
What happens when P. ramorum is
detected in a nursery
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
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
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
Similar symptoms
• Phytophthora root
disease and canker
• Armillaria root
disease
Bacterial stem diseases
• Bacterial
wetwood
• Bleeding stem
cankers caused
by Pseudomonas
syringae
Important hosts of P. ramorum in
WA nurseries
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Rhododendron
Camellia
Viburnum
These genera account
for over 90% of the
positive finds in
Washington nurseries
• Others –
– Pieris
– Kalmia
Rhododendron
Shoot blight
Leaf blotch on pacific
rhododendron caused by
Phytophthora ramorum.
Photo by Oregon Department of Forestry.
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
Root rot of rhododendron
Phytophthora root rot - not caused by P. ramorum
Photo: Jay Pscheidt, Oregon State University
Slide from the USDA PRED Training Module
Leaf necrosis of Rhododendron
Sun scorch, lesion
does not extend
down leaf midrib
Photo: Rich Regan, Oregon State University
Gray blight can develop on sun
scorched Rhododendron leaves
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
Symptoms on camellia
 Look for lower leaves
that have fallen off
Photo: Cheryl Blomquist, CDFA
Sun Scorch of Camellia
Brown spot not extending along petiole or midrib of leaf
Slide by Norm Dart
Viburnum
V. plicatum “Mariesii”
Viburnum tinus “Spring Bouquet”
V. davidii
Symptoms
Grey mold
• Stem canker
• Foliage and shoot blight
Botrytis
P. ramorum
Some other hosts
Grand fir
Bigleaf maple
Pacific madrone
Lilac
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
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.ht
ml
 Please consult the plant clinic before sending samples
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