Submitted to: National Viticulture Research Conference
Publication Type: Abstract Only
Publication Acceptance Date: 8/5/2008
Publication Date: 9/10/2008
Citation: Baumgartner, K., Bergemann, S., Fujiyoshi, P.T., Rolshausen, P., Gubler, W. 2008. IDENTIFYING SOURCES OF INOCULUM FOR EUTYPA DIEBACK INFECTIONS IN VINEYARDS. National Viticulture Research Conference.
Technical Abstract: The means of spread of Eutypa dieback from vine-to-vine within vineyards is likely due to dispersal of sexual spores (ascospores) of the causal fungus, Eutypa lata, based on evidence of distributions of vegetative compatibility groups, reproductive structures (perithecia), and symptoms. Asexual spores (conidia) are produced in nature, but are not infectious. Ascospores are released from perithecia following rain and are wind-dispersed. They infect grapevine vascular tissue by colonizing susceptible wounds (e.g., pruning wounds, freeze-damaged tissue). Although it seems clear that ascospores initiate infections of vines, the origin of ascospores that initiate the first infections in a healthy vineyard is not clear. Possible sources include distant vineyards, forest trees, or apricot orchards. To evaluate the relatedness of E. lata populations from vineyards, forests, and apricot orchards, we isolated and characterized nine E. lata-specific microsatellite markers. As numerous Eutypa species infect grapevines, forest trees, and apricots, we also evaluated our markers for E. armeniacae, E. laevata, E. leptoplaca, and E. petrakii var. petrakii. These closely related species are not distinguishable from E. lata in culture, and it is, therefore, critical to ensure that markers will not inadvertently amplify isolates of different species.