Fusarium fujikuroi is a seed-borne pathogen and the causal agent of Bakanae disease.When seeds are colonized by F.fujikuroi, the infected seedlings can show abnormal elongation of stem or internodes, thin leaves, wider leaf angle, and even die.Furthermore, it can cause considerable yield loss in the field.Although Bakanae disease has been known in Taiwan for over one hundred year, the resistance mechanism of rice to Bakanae disease remains unknown.This is partly due to the complexity of Bakanae disease symptoms, which are quite diversified and can be easily affected by environmental conditions.To solve this problem, this study will focus on developing more precise disease evaluation methods.We plan to evaluate disease level by (1) direct visual observation following a 0-3 rating scale, (2) using an image analysis system to acquire detailed information of symptoms, and (3) quantification of F.fujikuroi colonization in the seedling with a selective medium.With comparison of three evaluation methods, we expect the results of this study can facilitate further researches on Bakanae disease.