Location: Tropical Plant Genetic Resources and Disease ResearchTitle: Presence and viability of Ceratocystis lukuohia in ambrosia beetle frass from rapid 'ohi'a death-affected Metrosideros polymorpha trees on Hawai'i island
|KYLLE, ROY - Us Geological Survey (USGS)|
|EWING, CURTIS - University Of Hawaii|
|HUGHES, MARC - University Of Hawaii|
|BENNETT, GORDON - University Of Hawaii|
Submitted to: Forest Pathology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 10/15/2018
Publication Date: 2/1/2019
Citation: Kylle, R., Ewing, C., Hughes, M., Keith, L.M., Bennett, G. 2019. Presence and viability of Ceratocystis lukuohia in ambrosia beetle frass from rapid 'ohi'a death-affected Metrosideros polymorpha trees on Hawai'i island. Forest Pathology. 49(1). https://doi.org/10.1111/efp.12476.
Interpretive Summary: A study was conducted to better understand the mechanism of spread of Rapid 'Ohi'a Death (ROD) by determining the prevalence and viability of Ceratocystis lukuohia in boring dust produced by ambrosia beetles attacking infested 'ohi'a trees.
Technical Abstract: Rapid 'Ohi'a Death (ROD) is a colloquially termed fungal disease of the 'ohi'a lehua (Myrtaceae: Metrosideros polymorpha) tree that is causing widespread mortality on Hawai'i Island, but the mechanism of its spread remains unclear. We investigated ambrosia beetle(Coleoptera: Scolytinae) emergence and the prevalence and viability of Ceratocystis lukuohia in boring dust produced by the wood-boring activities of ambrosia beetles attacking infected 'ohi'a trees. A total of 200 boring-dust collection traps were placed onto symptomatic 'ohi'a trees at four locations on the east side of Hawai'i Island. Boring dust was collected and screened for the presence of C.lukuohia DNA using a diagmostic qPCR assay. In addition, boring dust samples were screened for viability with a carrot bait method. All beetles collected in traps were of the genus Xyleborus, with the majority being the non-native X.ferrugineus. Of the boring dust samples tested, 62% contained C.lukuohia DNA and 17% of carrot baits were positive for the fungus. These results implicate ambrosia beetle boring dust as a mechanism for releasing C.lukuohia into the environment and its potential to serve as inoculum in the ROD pathosystem.