Epidemiology of ‘bois noir’ disease and molecular variabilityof associated phytoplasmas in organic vineyards in Tuscany(Italy)

The spread of ‘bois noir’ disease in grapevine was monitored in three organic vineyards in Tuscany (Italy). Annual incidence, infection and recovery rates were calculated to describe changes in the epidemic with time. In general symptomatic plants showed the recovery in a relatively short time, meanwhile the infection rate decreased rapidly after the second year of assessments. The temporal dynamics of infection and recovery rates were satisfactorily fitted to a power and polynomial models, respectively. Survey on the herbaceous vineyard weeds allow to identify 16SrXII phytoplasmas, polymorphisms in 16Sr and tuf genes were detected.