, a Novel Causal Agent of Leaf Blotch and Its Sensitivity to Fungicides.

Ker-Gawl is native to Asia and is usually used as a garden ornamental. In September 2022, a leaf blotch on was observed in Nanjing, Jiangsu, China. The disease causes the leaves of the plants to curl and dry up and defoliate early. It not only seriously affects the growth of the plants but also greatly reduces the ornamental value. The pathogenic fungus was isolated from the diseased leaves, and the fungus was identified to be based on morphological features and multilocus phylogenetic analyses of the internal transcribed spacer (ITS) region, actin (), calmodulin (), beta-tubulin 2 (), chitin synthase (), Apn2-Mat1-2 intergenic spacer and partial mating type (), and glyceraldehyde-3-phosphate dehydrogenase () genes. Pathogenicity tests were performed by inoculating healthy leaves with conidia. can grow at 15-35 °C, with an optimal growth temperature at 25-30 °C. The results of sensitivity to nine fungicides showed that was the most sensitive to prochloraz in the concentration range of 0.01 μg/mL to 100 μg/mL. Therefore, spraying prochloraz before the optimum growth temperature of pathogenic fungus can achieve effective control. It provided useful information for future studies on the prevention and treatment strategies of . This is the first report of leaf blotch caused by on in China and worldwide.