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The Influence of Climate on Foliar Symptoms of Eutypa Dieback in Grapevines

First, third, and fourth authors: South Australian Research and Development Institute, GPO Box 397, Adelaide, SA, 5001 Australia; second author: Department of Plant Pathology, ARO, the Volcani Center, Bet Dagan, 50250, Israel; and fifth and sixth authors: School of Agriculture, Food and Wine, The University of Adelaide, Waite Campus, Glen Osmond, SA, 5064 Australia.

Foliar symptoms of Eutypa dieback, caused by Eutypa lata, in grapevines, cv. Shiraz, varied from year to year in a 6-year study conducted in South Australia and, although trends were similar for vineyards within geographical regions, differences were observed between regions. We attempted to elucidate the causes underlying this variation and hypothesized that it was influenced by climatic factors. A number of possible relationships were identified between climate and symptom expression: (i) increased symptom expression was related to increased winter rainfall 18 months earlier, (ii) decreased disease incidence and prevalence were related to increased temperature in spring, and (iii) a reduction in disease incidence was related to both very high and very low rainfall in October. Theories for these relationships are proposed and require further investigation. A conceptual model was developed which requires validation and has the potential to predict the incidence of foliar symptoms of Eutypa dieback. Information from this study could lead to an improved integrated pest management system to suppress foliar symptoms and sustain productivity of vines infected with E. lata.

Additional keywords:Vitis vinifera.