Latent Infection by Clavibacter sepedonicus and Correlation with Ring Rot Symptoms Development in Potato Cultivars


The aim of this study was to determine the response of potato cultivars to Clavibacter sepedonicus (Cs) infection in a field experiment. The research focused on the infection in a latent form as it is a risk for unnoticed spread. A total of 18 cultivars were tested in the years 2013–2016. Symptoms of the disease were observed on the leaves during growth and in tubers after harvest and after storage. The infection incidence was determined by microscopic observation of leaf and tuber samples stained by the IFAS method. A diverse response of potato cultivars to Cs infection was found. The lowest number of asymptomatic infected plants was found in cultivars ‘Vineta’, ‘Bila’ and ‘Irga’. As for cultivar ‘Stasia’, the entire tuber yield was latently infected by Cs. A low or medium concentration of Cs cells in leaves did not change significantly or increased depending on the potato cultivar. A higher incidence of tubers with disease symptoms was found after the storage period. In eight of the cultivars tested, the level of tuber infection by Cs confirmed microscopically after harvest was significantly correlated with the occurrence of disease symptoms in tubers after the storage period.