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Research Project: Sustainable Approaches for Pest Management in Vegetable Crops

Location: Vegetable Research

Title: Thousand cankers disease research: The good, the bad and the ugly

item HADZIABDIC, DENITA - University Of Tennessee
item GAZIS, ROMINA - University Of Tennessee
item OREN, EMEL - University Of Tennessee
item KLINGEMAN, WILLIAM - University Of Tennessee
item VITO, LISA - University Of Tennessee
item WINDHAM, MARK - University Of Tennessee
item POPLAWSKI, LAURA - University Of Tennessee
item LAMBDIN, PARIS - University Of Tennessee
item GRANT, JEROME - University Of Tennessee
item WIGGINS, GREGORY - University Of Tennessee
item Wadl, Phillip
item OWNLEY, BONNIE - University Of Tennessee
item STATON, MARGARET - University Of Tennessee
item MOULTON, JOHN - University Of Tennessee
item MERTEN, PAUL - Forest Service (FS)
item PSCHEIDT, JAY - Oregon State University
item CRANSHAW, WHITNEY - Colorado State University
item FACCOLI, MASSIMO - University Of Padua
item JUZWIK, JENNIFER - Forest Service (FS)
item GINZEL, MATTHEW - Purdue University
item TRIGIANO, ROBERT - University Of Tennessee

Submitted to: International Congress of Entomology
Publication Type: Abstract Only
Publication Acceptance Date: 5/16/2016
Publication Date: 8/22/2016
Citation: Hadziabdic, D., Gazis, R., Oren, E., Klingeman, W., Vito, L., Windham, M., Poplawski, L., Lambdin, P., Grant, J., Wiggins, G., Wadl, P.A., Ownley, B., Staton, M., Moulton, J., Merten, P., Pscheidt, J., Cranshaw, W., Faccoli, M., Juzwik, J., Ginzel, M., Trigiano, R. 2016. Thousand cankers disease research: The good, the bad and the ugly. XXV International Congress of Entomology. doi:10.1603/ICE.2016.89390.

Interpretive Summary: N/A

Technical Abstract: The plant pathogenic fungus, Geosmithia morbida, vectored by the walnut twig beetle (WTB), Pityophthorus juglandis, has been associated with a disease complex of walnuts, Juglans spp., known as thousand cankers disease (TCD). TCD, originally described from the western U.S., has now expanded to the native range of black walnut (J. nigra) in the eastern United States. TCD has recently been discovered in northwestern Italy on both black and native English walnut (J. regia). Due to pathogen movement and possible global distribution, there is a critical need to understand genetic diversity and population structure of the fungal pathogen, G. morbida, and its vector, WTB. The latest findings of co-infection of G. morbida with Fusarium solani species 25 suggested an uncommon synergistic two-fungal pathosystem that could weaken the host. Our current research indicates two overlapping WTB generations per season in the U.S. and Italy. We have developed rapid molecular detection for G. morbida and insect vector using microsatellite loci, significantly reducing disease confirmation time. We have found high genetic diversity among G. morbida subpopulations in the U.S. and Italy with evidence of gene flow and a significant correlation between geographic and genetic distance. Bayesian clustering analyses identified five distinct genetic fungal clusters with no evidence of sexual reproduction or genetic recombination. Our results support the hypothesis that G. morbida was disseminated to different regions multiple times from multiple sources. Understanding genetic structure of the members of this disease complex, as well as their interactions, can aid in future predictions of TCD occurrences.