Classification of the disease used for the distribution map was in five incidence—number of plants with symptoms—classes, in order to receive one value for disease severity per site (mean of incidence classes for 10 plants): CMD, incidence class 1=no symptoms, class 2=1–25%, class 3=26–50%, class 4=51–75%, class 5=76–100% of shoot tips infected; CBB, incidence class 1=no symptom, class 2=plants with water-soaked spots only, class 3=plants with water-soaked spots and 1–50% of plants with systemic infection (corresponding to symptom classes 4 and 5), class 4=51–89% of plants with systemic infection, class 5=over 90% of plants with systemic infection. This classification allowed to calculate the means over the incidence classes per site. Prevalence was defined as field incidence: percentage of infected fields per ecozone.