The decline of the young vines grafted onto 161-49 C
Résumé
The 161-49 C is a rootstock widely used in France. In 2010, its surface represented more than 4% of potential of the nurseries (82 ha), ranking in 8th position for rootstock varieties in France (statistics 2011 from FranceAgriMer). Although ten clones are officially registered in the French catalogue, clones 176 and 198 represent 85% of the total potential of production. For 6-8 years, severe declines of young vines grafted with this rootstock have been reported in several vineyards of Languedoc (south of France). While the number of declines increased in Languedoc, similar cases were reported in other French and foreign vineyards. Given the importance of the problem for the viticulture industry, a survey was performed in France to identify affected plots, assess the extent of decline, and to try to identify factors potentially involved in the decline. The first goal of this paper is to report main results of this survey, which was performed on about 230 plots. Another aim of this study is to describe the specific symptoms associated with the syndrome, which can be confused with several other issues (tyloses, black-foot disease, viruses, physiological problems, soil infertility, etc.). Vines sampled in several plots were submitted to a range of observations and anatomical analyses. In this paper, we present and discuss the symptoms and the anatomy alterations associated with the disorder.