Trunk disease represents the next great threat for the wine industry, posing a far greater risk than phylloxera, according to consultant viticulturalist Dr Richard Smart.
The cankerous effect of esca on a vine’s vascular system. Photo credit: UC Davis
Speaking at the International Sparkling Wine Symposium, which is taking place this week at Denbies Wine Estate in the UK, Smart’s warning formed the conclusion to his presentation on current and future sparkling wine regions.
Smart noted that trunk disease, a fungal pathogen that encompasses esca, botryosphaeria and eutypa dieback, “is now more widespread in the world than phylloxera”, the louse that ravaged European vineyards during the late 19th century.
Even before it eventually kills the vine, trunk disease puts economic pressure on producers as a result of the reduced yields it causes, as well as the costs of chemical preventative measures and, eventually, replanting unproductive vines.
Smart attributed its rapid proliferation in particular to the international trade in vine material through nurseries, which are either unaware of the disease’s presence or lax in allowing infected plants to be sent around the world.
Noting that trunk disease “spreads more slowly” and “kills the plant more slowly”, Smart explained: “that’s the reason why there hasn’t been the panic of phylloxera.”
Richard Smart addresses delegates at the International Sparkling Wine Symposium
However, he added that, while the phylloxera crisis was eventually resolved by the use of resistant American rootstock, there is “presently no control” for trunk disease.
Linking its spread to the theme of his presentation, Smart suggested that trunk disease “is especially damaging in cool and wet regions”; in short, the same grape growing regions that are currently attracting increased investment from producers in search of cool climate, marginal ripening conditions.
Only last week Louis-Fabrice Latour, president of grower and négociant Maison Louis Latour, attributed Burgundy’s recent decline in production in part to the effects of esca.