A characterization of grapevine trunk diseases in France from data generated by the National Grapevine Wood Diseases Survey.

Farmers' field survey data sets represent extremely valuable information, often having a heterogeneous data format. A large number of methods are available to process this kind of information, which may be combined to address successive, connected hypotheses, with definite objectives. The National Grapevine Trunk Diseases Survey was established in France in order to monitor and analyze the importance and progress of several grapevine diseases, in particular Eutypa dieback and Esca decline. Here we report a first series of analyses pertaining to the years 2003 to 2005 to characterize the incidences of the two diseases, as well as grapevine mortality, in relation to grapevine age, crop management, cultivars, and growing regions. Information representing 256 individual vineyards indicated mean incidences of 2.23 and 3.25% for Eutypa dieback and Esca decline, respectively. A combination of approaches (hierarchical cluster analysis, multiple correspondence analyses, and binomial logistic regressions) indicated distinct patterns of variation in the incidences of the two diseases according to crop management practices; limited linkage of specific crop management practices with diseases, especially Esca decline; a shared contribution of both diseases to mortality; and a weak linkage of the (now banned) arsenite-based pesticides with reduced Esca decline symptoms, but no such association with grapevine mortality. Differences and complementarities of the analytical approaches are discussed, as well as the implications of these analyses on grapevine health.