Foamy Bark Canker. A New Insect-Disease Complex on Coast Live Oak in California Caused by Western Oak Bark Beetle and Geosmithia sp.

Transcription

1 Foamy Bark Canker A New Insect-Disease Complex on Coast Live Oak in California Caused by Western Oak Bark Beetle and Geosmithia sp. Shannon Lynch 1,2, Suzanne Rooney-Latham 3, Akif Eskalen 2 1. Center for Conservation Biology, UC Riverside 2. Department of Plant Pathology and Microbiology, UC Riverside 3. California Department of Food and Agriculture

2 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

3 Foamy Bark Canker on Coast Live Oak Photo: Robert Sartain, Santa Clarita

4 Foamy Bark Canker on Coast Live Oak Photo: Robert Sartain, Santa Clarita Santa Clarita, Los Angeles County CA Open Space

5 Foamy Bark Canker on Coast Live Oak Santa Clarita, Los Angeles County CA Private Property

6 Foamy Bark Canker on Coast Live Oak Santa Clarita, Los Angeles County CA Private Property

7 Foamy Bark Canker on Coast Live Oak Thousands Oaks, Ventura County Private Property

8 Foamy Bark Canker on Coast Live Oak Photo Credit: Bruce Schaar San Mateo County

9 Foamy Bark Canker on Coast Live Oak Arroyo Grande, San Louis Obispo County Photo Credit: Dawn Fluharty Private Property

10 Western Oak Bark Beetle Morphological ID: Dr. Robert Rabaglia USDA Forest Service Molecular ID: Stouthamer lab UCR 94% Match based on COI gene

11 Fungus and Beetle Association Geosmithia sp. Geosmithia sp. conidiophore Geosmithia sp. conidia

12 Area of Detection in California Q. agrifolia + Q. rubra Q. wislizeni Confirmed by UCR Confirmed by CDFA

13 Maximum likelihood phylogeny based on ITS sequences Oak687 Oak1068 Oak1527 Oak Oak1180 Oak520 Oak1131 Oak Oak1179 Oak1151 HF Geosmithia fassatiae HF Geosmithia fassatiae HF Geosmithia fassatiae HF Geosmithia fassatiae Oak1518 Oak1298 KJ Geosmithia flava 89 KJ Geosmithia flava 77 KJ Geosmithia flava KJ Geosmithia flava HE Geosmithia sp. HE Geosmithia sp. 94 HE Geosmithia sp. HE Geosmithia sp. KF Geosmithia langdonii KF Geosmithia langdonii KF Geosmithia langdonii HF Geosmithia langdonii HF Geosmithia pallida HF Geosmithia pallida 64 HF Geosmithia pallida HF Geosmithia pallida CDFA1654 Redoak 100 TOakwobb2075 CL CDFA CL HF Geosmithia pallida HF Geosmithia pallida 65 Oakwobb2208 CL Oakwobb2209 CL Oakwobb2210 CL AM Geosmithia sp. UCR2897 Geosmithia lavendula 92 KF Geosmithia lavendula 99 KF Geosmithia lavendula Geosmithia fassatiae Geosmithia flava Geosmithia sp. Geosmithia langdonii Geosmithia pallida Geosmithia lavendula

14 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

15 Symptoms of Foamy Bark Canker

16 Quercus wislizeni Photo: Jessica Honeycutt from El Dorado Co. Dept of Ag.

17 Symptoms of Foamy Bark Canker

18 Symptoms of Foamy Bark Canker

19 Symptoms of Foamy Bark Canker

20 Phloem necrosis and xylem streaking caused by the fungus Thousand Oaks, CA Santa Barbara, CA

21 WOBB Galleries Branch Trunk

22 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 dies

23 Larval Galleries Parent Gallery Fungal grows within the secondary gallery walls. Photo: Suzanne Latham

24 vascular necrosis (cm) Pathogenicity Test A Geosmithia pallida B Control Average extent of vascular necrosis (cm) produced in Q. agrifolia shoots artificially inoculated with G. pallida.

25 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

26 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

27 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

28 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

29 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

30 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

31 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

32 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

33 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