Phytophthora ramorum:
Educate to Detect
(PRED)
USDA-Forest Service
USDA-Cooperative State Research Education & Extension Service
IPM Regional Centers
National Plant Diagnostic Network
USDA-Animal and Plant Health Inspection Service
Overview
 Introduction to PRED
 History of P. ramorum
 Symptoms and look-alikes
 Regulations
 Sample collection and handling
History outline
 Status in North American forests
 Status in Europe
 Status in North American landscapes
and nurseries
Marin County, CA (north of San Francisco)
Photo: Marin County Fire Department
Marin County, CA (north of San Francisco), 2000
Photo: Marin County Fire Department
Phytophthora ramorum
Sporangia releasing
zoospores
Phytophthora ramorum in culture
Photo: UC Davis & UC Berkeley
Chlamydospores
Phytophthora species
Photo: William Fry, Cornell University
Phytophthora ramorum infection on the leaves of California bay laurel (Umbellularia californica)
Photo: Joseph O’Brien, USDA-Forest Service
Two sets of symptoms caused by
Phytophthora ramorum
 Sudden Oak Death
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Red oak group hosts and tanoak
Stem lesions beneath the bark
May bleed or ooze
Can kill adult plants
 Phytophthora ramorum Foliar Blight
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Non-oak hosts
Spots and blotches on leaves
Shoot dieback
Can kill juvenile plants, occasionally mature plants
Photo: Mike McWilliams, ODF
Photo: Everett Hansen, Oregon State University
P. ramorum
confirmations in forests
Map from www.suddenoakdeath.org
Kelly, UC-Berkeley
Map: USDA- Forest Service
European garden & nursery finds
Phytophthora ramorum infection on rhododendron in Europe
Photo: Hans DeGruyter, Netherlands Plant Protection Institute
Infected trees in
Europe
Quercus rubra
Fagus sylvatica
Photo: DEFRA
Photo: Jennifer Parke, Oregon State University
Trace-forward & trace-back
investigations
Trace forwards = to the nurseries where
stock was shipped TO
Trace backs = to the nursery where stock
was shipped FROM
Phytophthora ramorum
national survey
 Most states have started or completed their surveys
 Over 3000 nurseries / garden centers have been
surveyed
 Over 50,000 samples have been taken
 As of October 2004, this survey has identified 15
confirmed finds in 7 states: California, Oregon,
Washington, Maryland, Oklahoma, New Jersey and
Virginia
Photo: Jonathan Jones, APHIS, PPQ
Distribution of infected nursery stock from individual nurseries
Map: USDA, APHIS, PPQ
Trace-forwards and positive detections across the U.S.
July 2004
Map: USDA, APHIS, PPQ
Symptoms & look-alikes
 Sudden Oak Death on oak hosts
 Symptoms on other hosts
 Screening questions at the NCIPM
website (www.ncipm.org/sod):
 focus on recently purchased (or near recently
purchased) camellia, kalmia, lilac, pieris,
rhododendron, or viburnum
Symptoms caused by P. ramorum
differ on different hosts
Sudden Oak Death
affects members of the oak family
(Fagaceae)
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True oaks (Quercus spp.)
Tanoak (Lithocarpus densiflorus)
Chestnut (Castanea) [Europe only]
Beech (Fagus) [Europe only]
P. ramorum on coast live oak
Photo: Pavel Svihra, UC Cooperative Extension
‘Bleeding’ canker on tree trunk
 ‘Bleeding’ or oozing
on the bark
 Not associated with
cracks in bark or
insect holes
 Usually on the
lower 6 ft. of tree
trunks
Photo: Garbelotto lab, UC Berkeley
Phytophthora ramorum
“bleeding”
Photos: Mike McWilliams, ODF & Bruce Moltzen, Missouri Dept. of Conservation
Phytophthora ramorum
Cankers (in inner
bark) are surrounded
by a black line
Photo: Dave Rizzo, UC Davis
Phytophthora ramorum
outer bark
Photo: Bruce Moltzen, Missouri Department of Conservation
inner bark
Similar symptoms – not P. ramorum
outer bark
inner bark
Bleeding canker caused by Armillaria
Photo: Steve Oak, USDA-Forest Service
Similar symptoms – not P. ramorum
outer bark
inner bark
Bleeding canker caused by inner-bark boring insect
Photo: Steve Oak, USDA-Forest Service
Similar symptoms – submit sample
outer bark
inner bark
Bleeding canker caused by Inonotus hispidus
Photo: Steve Oak, USDA-Forest Service
Other common diseases & injuries
 Bacterial wetwood
 Boring insects
 Mechanical injury
 Fungi
On other plant hosts, P. ramorum
causes symptoms of foliar blight
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Camellia
Rhododendron
Viburnum
Pieris
Mountain laurel
Lilac
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Pyracantha
Honeysuckle
Yew
Douglas-fir
Grand fir
Coast redwood
Symptoms on camellia
Photos: Oregon Dept. of Agriculture & Cheryl Blomquist, CDFA
Symptoms on camellia
Photo: Cheryl Blomquist, CDFA
Symptoms on camellia
 Symptoms can be
subtle
 Look for irregularshaped brown lesions
on the leaves
 Sometimes only the
tips of leaves are
brown
 Look for lower leaves
that have fallen off
Photo: Cheryl Blomquist, CDFA
Similar symptoms – submit sample
Sun scorch on camellia
Photo: Carrie Harmon, University of Florida
Similar symptoms – submit sample
Cold injury on camellia
Photo: Richard Regan, Oregon State University
P. ramorum symptoms on
rhododendron
Shoot dieback
Foliar blight
Rhododendron macrophyllum
Photo: Everett Hansen, Oregon State University
Foliar blight
P. ramorum symptoms on
rhododendron
Photo: Everett Hansen, Oregon State University
Rhododendron macrophyllum
P. ramorum symptoms on
rhododendron
Photo: Bruce Moltzen, Missouri Dept. of Conservation
P. ramorum symptoms on
rhododendron
Rhododendron ‘Unique’
Photo: Jennifer Parke, Oregon State University
P. ramorum symptoms on eastern
native rhododendrons
(inoculation trials)
Photo: Paul Tooley, USDA-ARS
Similar symptoms – submit sample
Foliar blight caused by Phytophthora syringae
Photo: Jay Pscheidt, Oregon State University
Similar symptoms – submit sample
Foliar blight caused by Phytophthora species
Photo: Mike Benson, NCSU
Similar symptoms – not P. ramorum
Phytophthora root rot - not caused by P. ramorum
Photo: Jay Pscheidt, Oregon State University
Similar symptoms – not P. ramorum
Sun scorch
Gray blight can develop on sun
scorched rhododendron leaves
Photo: Rich Regan, Oregon State University
Symptoms on pieris
Pieris japonica
Photo: Oregon Dept. of Agriculture
P. ramorum symptoms on pieris
Photo: Oregon Dept. of Agriculture
Pieris japonica
P. ramorum symptoms on viburnum
Viburnum x bodnantense ‘’Dawn’
Photo: Oregon Dept. of Agriculture
P. ramorum symptoms on viburnum
Viburnum x bodnantense ‘Dawn’
Photo: Oregon Dept. of Agriculture
P. ramorum symptoms on viburnum
Viburnum plicatum tomentosum ‘Mariesii’
Photo: Jennifer Parke, Oregon State University
P. ramorum symptoms on viburnum
stem
canker
Photo: Sabine Werres, Institut für Pflanzenschutz im Gartenbau, Germany
P. ramorum symptoms on kalmia
(mountain laurel)
Photo: DEFRA
Similar symptoms – submit sample
Kalmia latifolia (mountain laurel)
Photo: Robert Linderman, USDA-ARS
Similar symptoms – submit sample
Kalmia latifolia (mountain laurel)
Photo: Peter Angwin, USDA-Forest Service
P. ramorum symptoms on lilac
Photo: Alexandra Schlenzig, Scottish Agricultural Science Agency
Similar symptoms – submit sample
Bacterial blight on lilac
Photo: Jay Pscheidt, Oregon State University
P. ramorum symptoms on conifers
Grand fir
Photo: Santa Clara Co. (CA) Agriculture Dept. & Dave Rizzo, UC Davis
Douglas-fir
Regulations
 Federal and State quarantines
 Domestic Regulated Materials
 Federal P. ramorum quarantine
program goals
Phytophthora ramorum
regulations & quarantines
 Federal quarantines –
 prevent movement between states
 State quarantines –
 prevent movement within a state
 prevent introductions
Phytophthora ramorum
domestic regulated materials
 Nursery stock
 Bark
 Forest stock
 Soil
 Wood
 Wreaths & greenery
Phytophthora ramorum host list
tanoak
horse-chestnut
canyon live oak
sweet chestnut
coast live oak
European beech
California black oak
drooping leucothoe
Shreve oak
European turkey oak
bigleaf maple
toyon
coffeeberry
cascara
California buckeye
coast redwood
salmonberry
manzanita
Western starflower
grand fir
California hazelnut
Douglas-fir
mountain laurel
European yew
Pieris varieties
strawberry tree
Camellia species
California wood fern
European yew
Pacific yew
false Solomon’s seal
winter’s bark
goat willow
Andrew’s clintonia bead lily
California bay laurel/pepperwood
Current as of August 16, 2004
southern red oak
northern red oak
Holm oak
wood rose
Viburnum varieties
madrone
Formosa firethorn
huckleberry
honeysuckle
poison oak
Scotch heather
witch-hazel
Victorian box
lilac
rhododendrons/azaleas
sweet bay laurel
Federal P. ramorum quarantine
program goals
 Prevent the artificial spread of P. ramorum
 Take the least restrictive action necessary
 Determine status of disease, nationwide
 Keep the regulations current with the science and risk
 Identify where infected items came from and went to
 Clean up infested nurseries and garden centers
APHIS website:
www.aphis.usda.gov/ppq/ispm/sod
P. ramorum procedures
 Review of material just presented
 Goal of PRED
 Overview of the program
 What to do…
Sample referral and submission
 In some states, only the State or federal
regulatory officials will be collecting the
specimens.
 Contact your county extension agent or
supervisor to find out who is authorized to
collect suspect samples in your county.
Sample referral criteria
 Plants likely to be infected by Phytophthora
ramorum (as indicated by the screening
questionnaire):
 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
 Screening questions at the NCIPM website:
(www.ncipm.org/sod)
Communication
 Submit the suspect sample to:
 County Extension Specialist/Farm Advisor
 Master Gardener
 Other state designated representative
 Avoid alarming behavior. Don’t jump to
conclusions.
 Wait for lab result
 Maintain confidentiality
If you’re asked to collect a sample
 Collect leaves that
show various stages
of symptom
development.
 Take pictures of
symptoms and
environment.
Packaging a sample
 Place sample on a paper
towel. Do not wet the
towel.
 Double bag and seal the
sample in zippable bags.
 If shipping, use a crush
proof box with seams
sealed completely with
tape.
 Be sure to include the
sample submission form
required by your state.
Delivering a sample
 Contact the sample recipient.
 Samples must be fresh and in good condition.
 Rapid delivery is critical (no Friday
shipments).
Sampling reminders
 The accuracy of a disease diagnosis can
only be as good as the sample and
information provided.
 Sample must be representative of
symptoms and severity in the field and must
contain the right material.
Sampling reminders
 Sanitation
 disposal of material
 containment while shipping
 clean tools
 Chain of custody
 restrict access to sample
 make sure sample collection location is
retraceable
Diagnostics: laboratory tests
 There are three detection
methods:
 Antibody test (ELISA)
 Plating on selective media
 DNA (PCR)
 Relatively expensive
ELISA
Plating
 Time consuming
PCR
Photo: Natalie Goldberg, New Mexico State University
Where to go for more information
 APHIS:
www.aphis.usda.gov/ppq/ispm/sod
 California Oak Mortality Task Force:
www.suddenoakdeath.org
 NCIPM:
www.ncipm.org/sod
Acknowledgments
 Authors
 Jennifer Parke
 Susan Frankel
 Janice Alexander
 Carla Thomas
 Reviewers
 Kitty Caldwell
 Eugene Erickson
 Jonathan Jones
 Natalie Goldberg
 Everett Hansen
 Carrie Harmon
 John Hartman
Bill Hoffman
Steve Oak
Melodie Putnam
Susan Ratcliffe
David Rizzo
Stacy Scott
Questions???
 We have assembled a group of experts to
answer your questions:
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David Rizzo, University of California, Davis
Jonathan Jones, APHIS
Jennifer Parke, Oregon State University
Kerry Britton, USDA-Forest Service
Carla Thomas, NPDN
Susan Ratcliffe, NCIPM