Pathogenicity evaluation of Ralstonia pseudosolanacearum race 4 on ginger by leaf-clipping inoculation

An easy, rapid method has been needed to test the pathogenicity of strains of Ralstonia pseudosolanacearum , the cause of serious bacterial wilt on ginger ( Zingiber officinale ). When ginger leaves were clip-inoculated with race 4 strains, yellowing and V-shaped lesions developed on leaves, but no lesions formed after inoculation with race 1 strain or on mock-inoculated leaves. Tests of different bacterial concentrations as inoculum showed that the optimal concentration was greater than or equal to 10 6 cfu/ml. This simple, high-throughput leaf clipping inoculation method provides an efficient, easy method to evaluate pathogenicity of R. pseudosolanacearum race 4 on ginger.