First report of Leveillula taurica causing powdery mildew on Tropaeolum majus in Taiwan

Garden nasturtium (Tropaeolum majus), belonging to the family Tropaeolaceae, is a widely used ornamental plant. In April 2020, a powdery mildew was observed on garden nasturtium in central Taiwan. Symptoms included angular chlorotic lesions which later became brown and necrotic on both leaf surfaces. The fungus was identified as Leveillula taurica s. str. based on the morphology and the molecular analysis of ITS sequence. The powdery mildew was found on both T. majus and sweet pepper in the meantime. This is the first report of L. taurica causing powdery mildew on T. majus in Taiwan.