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Grapevine trunk diseases: a complex of related pathogens with global impacts

Laura Mugnai: DISPAA, University of Florence

<div>Grapevine trunk diseases (GTDs) have become a major concern worldwide, causing significant economic impact by reduced production and vineyard longevity. Petri disease and black foot affect young grapevines whilst the diseases Eutypa, Botryosphaeria and Phomopsis dieback, and esca affect mature grapevines. These diseases are caused by a wide range of fungal pathogens producing a range of symptoms including: leaf and shoot distortion and discolouration, external wood cankers and dieback, internal wood necrosis and staining, poor growth, mortality of roots and sudden vine collapse. The prevalence of GTDs has significantly increased with changes in production practices, loss of effective chemicals, predominance of susceptible cultivars and ageing of vineyards. Pruning wounds are the main infection portal for these pathogens and inoculum sources include a wide range of alternative hosts such as fruit crops and many introduced and/or native tree species. Due to the rapid expansion of wine regions, young vine disease is escalating, as pathogens can be introduced during propagation, and diseases are often associated with poor planting practices and stress. Control is limited to hot water treatment and fungicide dips, with mixed results. With the rapid development of molecular diagnostic capabilities, it is important to understand infection thresholds and the link with disease in the vineyard. A good understanding of the etiology, biology and epidemiology of GTD fungi has led to the development of effective management strategies in the vineyard, through wound protection and remedial surgery. Successful disease management requires a holistic approach from the nursery to the vineyard.</div>