Foamy Bark Canker A New Insect-Disease Complex on Coast Live Oak in California Caused by Western Oak Bark Beetle and Geosmithia sp.
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Foamy Bark Canker
A New Insect-Disease Complex on Coast Live
Oak in California Caused by Western Oak Bark
Beetle and Geosmithia sp.
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
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
Foamy Bark Canker on Coast Live Oak
Photo: Robert Sartain, Santa Clarita
Foamy Bark Canker on Coast Live Oak
Photo: Robert Sartain, Santa Clarita
Santa Clarita, Los Angeles County CA
Open Space
Foamy Bark Canker on Coast Live Oak
Santa Clarita, Los Angeles County CA
Private Property
Foamy Bark Canker on Coast Live Oak
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 Photo Credit: Bruce Schaar San Mateo County
Foamy Bark Canker on Coast Live Oak
Arroyo Grande, San Louis Obispo County
Photo Credit: Dawn Fluharty Private Property
Western Oak Bark Beetle
•Morphological ID:
•Dr. Robert
Rabaglia USDA
Forest Service
•Molecular ID:
•Stouthamer lab
UCR
•94% Match
based on COI
geneFungus and Beetle Association
Geosmithia sp.
Geosmithia sp. conidiophore Geosmithia sp. conidiaArea of Detection in California
Q. wislizeni
Q. agrifolia +
Q. rubra
Confirmed by UCR
Confirmed by CDFAMaximum likelihood Oak687
Oak1068
Oak1527
phylogeny based on ITS 65
Oak1489
Oak1180
Oak520
sequences 94
Oak1131
Oak1132
Geosmithia fassatiae
Oak1179
Oak1151
HF546338 Geosmithia fassatiae
HF546275 Geosmithia fassatiae
HF546272 Geosmithia fassatiae
56 61
HF546270 Geosmithia fassatiae
Oak1518
Oak1298
KJ513212 Geosmithia flava
89
KJ513211 Geosmithia flava
Geosmithia flava
77 KJ513208 Geosmithia flava
KJ513209 Geosmithia flava
HE604153 Geosmithia sp.
91 HE604152 Geosmithia sp.
Geosmithia sp.
94 HE604143 Geosmithia sp.
HE604134 Geosmithia sp.
KF914640 Geosmithia langdonii
KF808298 Geosmithia langdonii
Geosmithia langdonii
98 KF808297 Geosmithia langdonii
HF546356 Geosmithia langdonii
HF546281 Geosmithia pallida
HF546342 Geosmithia pallida
64
HF546311 Geosmithia pallida
HF546253 Geosmithia pallida
CDFA1654 Redoak
100
TOakwobb2075 CL
CDFA1580859-2 CL
Geosmithia pallida
HF546351 Geosmithia pallida
HF546349 Geosmithia pallida
65
Oakwobb2208 CL
Oakwobb2209 CL
Oakwobb2210 CL
AM4210771 Geosmithia sp.
UCR2897 Geosmithia lavendula
92 Geosmithia lavendula
KF808300.1|Geosmithia lavendula
99
KF808300.1 Geosmithia lavendulaGeosmithia 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 standsSymptoms 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
Thousand Oaks, CA Santa Barbara, CAWOBB Galleries Branch Trunk
The beetle burrows in the phloem to the level of the cambium where
she constructs ~2 cm galleries against the grain
1-2 cm
At one end of these primary galleries, the
female lays eggs, then builds a secondary
gallery half way up and diesLarval Galleries Parent Gallery
Fungal grows within the secondary gallery walls.
Photo: Suzanne LathamPathogenicity Test
9 A
8
vascular necrosis (cm)
7
6
5
4
3
2
1 B
0
Geosmithia pallida Control
Average extent of vascular necrosis (cm) produced in Q. agrifolia shoots artificially
inoculated with G. pallida.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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