Shannon Lynch1,2, Suzanne Rooney-Latham3, Akif Eskalen2
1. Center for Conservation Biology, UC Riverside
2. Department of Plant Pathology and Microbiology, UC Riverside
3. California Department of Food and Agriculture
Foamy Bark Canker A New Insect-Disease Complex on Coast Live Oak in California Caused by Western Oak Bark
Beetle and Geosmithia sp.
Background • A decline of coast live oak in California has been observed
since late 2012 throughout urban landscapes and private lands in Los Angeles, Orange, Riverside, Santa Barbara, Ventura and Monterey counties
Photo: Robert Sartain, Santa Clarita
Foamy Bark Canker on Coast Live Oak
Santa Clarita, Los Angeles County CA Open Space
Foamy Bark Canker on Coast Live Oak
Photo: Robert Sartain, Santa Clarita
Foamy Bark Canker on Coast Live Oak
Santa Clarita, Los Angeles County CA Private Property
Santa Clarita, Los Angeles County CA Private Property
Foamy Bark Canker on Coast Live Oak
Thousands Oaks, Ventura County Private Property
Foamy Bark Canker on Coast Live Oak
San Mateo County
Foamy Bark Canker on Coast Live Oak
Photo Credit: Bruce Schaar
Foamy Bark Canker on Coast Live Oak
Arroyo Grande, San Louis Obispo County Private Property Photo Credit: Dawn Fluharty
Western Oak Bark Beetle
•Molecular ID: •Stouthamer lab UCR •94% Match based on COI gene
•Morphological ID: •Dr. Robert Rabaglia USDA Forest Service
Fungus and Beetle Association
Geosmithia sp.
Geosmithia sp. conidiophore Geosmithia sp. conidia
Area of Detection in California
Q. wislizeni
Q. agrifolia + Q. rubra
Confirmed by CDFA
Confirmed by UCR
Maximum likelihood phylogeny based on ITS sequences
Oak687
Oak1068
Oak1527
Oak1489
Oak1180
Oak520
Oak1131
Oak1132
Oak1179
Oak1151
HF546338 Geosmithia fassatiae
HF546275 Geosmithia fassatiae
HF546272 Geosmithia fassatiae
HF546270 Geosmithia fassatiae
Oak1518
Oak1298
Geosmithia fassatiae
KJ513212 Geosmithia flava
KJ513211 Geosmithia flava
KJ513208 Geosmithia flava
KJ513209 Geosmithia flava
Geosmithia flava
HE604153 Geosmithia sp.
HE604152 Geosmithia sp.
HE604143 Geosmithia sp.
HE604134 Geosmithia sp.
Geosmithia sp.
KF914640 Geosmithia langdonii
KF808298 Geosmithia langdonii
KF808297 Geosmithia langdonii
HF546356 Geosmithia langdonii
Geosmithia langdonii
HF546281 Geosmithia pallida
HF546342 Geosmithia pallida
HF546311 Geosmithia pallida
HF546253 Geosmithia pallida
CDFA1654 Redoak
TOakwobb2075 CL
CDFA1580859-2 CL
HF546351 Geosmithia pallida
HF546349 Geosmithia pallida
Oakwobb2208 CL
Oakwobb2209 CL
Oakwobb2210 CL
Geosmithia pallida
AM4210771 Geosmithia sp.
UCR2897 Geosmithia lavendula
KF808300.1|Geosmithia lavendula
KF808300.1 Geosmithia lavendula
Geosmithia lavendula
99
65
64
100
92
98
94
91
89
77
56 61
94
65
Geosmithia pallida complex Kolarik et. al in press
• G. pallida is a complex of more species, but in the strict sense has previously been detected on oak species in Europe only.
• Identified G. pallida as Geosmithia sp. 41 recovered from Quercus spp. and other hosts associated with P. pubipennis and other beetles in CA in 2009
• ITS sequences of our isolates match with Geosmithia sp. 41
• Did not observe FBC symptoms, presuming the trees were over-run with P. ramorum
• Brief remarks from oaks sampled in non-infested P. ramorum stands
Symptoms of Foamy Bark Canker
Quercus wislizeni
Photo: Jessica Honeycutt from El Dorado Co. Dept of Ag.
Symptoms of Foamy Bark Canker
Symptoms of Foamy Bark Canker
Symptoms of Foamy Bark Canker
Phloem necrosis and xylem streaking caused by the fungus
Santa Barbara, CA Thousand Oaks, CA
WOBB Galleries Branch Trunk
The beetle burrows in the phloem to the level of the cambium where she constructs ~2 cm galleries against the grain
At one end of these primary galleries, the female lays eggs, then builds a secondary gallery half way up and dies
1-2 cm
Larval Galleries Parent Gallery
Fungal grows within the secondary gallery walls.
Photo: Suzanne Latham
Pathogenicity Test
0
1
2
3
4
5
6
7
8
9
Geosmithia pallida Control
A
B
Average extent of vascular necrosis (cm) produced in Q. agrifolia shoots artificially inoculated with G. pallida.
vasc
ula
r n
ecro
sis
(cm
)
Conclusions • Geosmithia sp. 41 (Kolarik et al. in press) was consistently
recovered from cankered tissues of Q. agrifolia associated with western oak bark beetle from different locations in CA
• The fungus was directly isolated from P. pubipennis and its gallery walls
• Earliest detection of the fungus is 2009 • Pathogenicity of Geosmithia sp. 41 was confirmed by
conducting Koch’s postulates. • Preliminary data suggest that the beetle collected from FBC
infested trees is a cryptic species, but a larger sample size (populations and loci) is needed to determine the precise taxonomic status of P. pubipennis.
• Drought stressed trees may be prone to attack by WOBB • Fungal growth appears to girdle the plant, causing branch
dieback and tree death
Conclusions • Geosmithia sp. 41 (Kolarik et al. in press) was consistently
recovered from cankered tissues of Q. agrifolia associated with western oak bark beetle from different locations in CA
• The fungus was directly isolated from P. pubipennis and its gallery walls
• Earliest detection of the fungus is 2009 • Pathogenicity of Geosmithia sp. 41 was confirmed by
conducting Koch’s postulates. • Preliminary data suggest that the beetle collected from FBC
infested trees is a cryptic species, but a larger sample size (populations and loci) is needed to determine the precise taxonomic status of P. pubipennis.
• Drought stressed trees may be prone to attack by WOBB • Fungal growth appears to girdle the plant, causing branch
dieback and tree death
Conclusions • Geosmithia sp. 41 (Kolarik et al. in press) was consistently
recovered from cankered tissues of Q. agrifolia associated with western oak bark beetle from different locations in CA
• The fungus was directly isolated from P. pubipennis and its gallery walls
• Earliest detection of the fungus is 2009 • Pathogenicity of Geosmithia sp. 41 was confirmed by
conducting Koch’s postulates. • Preliminary data suggest that the beetle collected from FBC
infested trees is a cryptic species, but a larger sample size (populations and loci) is needed to determine the precise taxonomic status of P. pubipennis.
• Drought stressed trees may be prone to attack by WOBB • Fungal growth appears to girdle the plant, causing branch
dieback and tree death
Conclusions • Geosmithia sp. 41 (Kolarik et al. in press) was consistently
recovered from cankered tissues of Q. agrifolia associated with western oak bark beetle from different locations in CA
• The fungus was directly isolated from P. pubipennis and its gallery walls
• Earliest detection of the fungus is 2009 • Pathogenicity of Geosmithia sp. 41 was confirmed by
conducting Koch’s postulates. • Preliminary data suggest that the beetle collected from FBC
infested trees is a cryptic species, but a larger sample size (populations and loci) is needed to determine the precise taxonomic status of P. pubipennis.
• Drought stressed trees may be prone to attack by WOBB • Fungal growth appears to girdle the plant, causing branch
dieback and tree death
Conclusions • Geosmithia sp. 41 (Kolarik et al. in press) was consistently
recovered from cankered tissues of Q. agrifolia associated with western oak bark beetle from different locations in CA
• The fungus was directly isolated from P. pubipennis and its gallery walls
• Earliest detection of the fungus is 2009 • Pathogenicity of Geosmithia sp. 41 was confirmed by
conducting Koch’s postulates. • Preliminary data suggest that the beetle collected from FBC
infested trees is a cryptic species, but a larger sample size (populations and loci) is needed to determine the precise taxonomic status of P. pubipennis.
• Drought stressed trees may be prone to attack by WOBB • Fungal growth appears to girdle the plant, causing branch
dieback and tree death
Conclusions • Geosmithia sp. 41 (Kolarik et al. in press) was consistently
recovered from cankered tissues of Q. agrifolia associated with western oak bark beetle from different locations in CA
• The fungus was directly isolated from P. pubipennis and its gallery walls
• Earliest detection of the fungus is 2009 • Pathogenicity of Geosmithia sp. 41 was confirmed by
conducting Koch’s postulates. • Preliminary data suggest that the beetle collected from FBC
infested trees is a cryptic species, but a larger sample size (populations and loci) is needed to determine the precise taxonomic status of P. pubipennis.
• Drought stressed trees may be prone to attack by WOBB • Fungal growth appears to girdle the plant, causing branch
dieback and tree death
Conclusions • Geosmithia sp. 41 (Kolarik et al. in press) was consistently
recovered from cankered tissues of Q. agrifolia associated with western oak bark beetle from different locations in CA
• The fungus was directly isolated from P. pubipennis and its gallery walls
• Earliest detection of the fungus is 2009 • Pathogenicity of Geosmithia sp. 41 was confirmed by
conducting Koch’s postulates. • Preliminary data suggest that the beetle collected from FBC
infested trees is a cryptic species, but a larger sample size (populations and loci) is needed to determine the precise taxonomic status of P. pubipennis.
• Drought stressed trees may be prone to attack by WOBB • Fungal growth appears to girdle the plant, causing branch
dieback and tree death
Future Work
• Determine taxonomic status of the beetle with more loci • Further identify the life cycle of the beetle (number of
generations per year, etc.) • Diet tests to determine function of the fungus in the life cycle
of the beetle • Inoculation trials to characterize disease progress in the
greenhouse • Identify olfactory cues that attract the beetle to trees • Compare water potential between infested and non-infested
trees • Monitor distribution and impact of pest/disease
Acknowledgements
Miroslav Kolarik: Academy of Sciences of the Czech Republic Kim Corella, CalFire Robert Sartain: Oak Specialist, Santa Clarita Melody Lardner, USDA, Forest Service Brian Carrera: Arborist, Santa Barbara and San Louis Obispo Phil Cannon, USDA, Forest Service Robert Rabaglia: USDA Forest Service Entomologist Tom Roberts: Pest Control Advisor, Ventura and Santa Barbara County Rebecca Latta: Arborist, Los Angeles County
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