First Report of Leaf Spot Caused by <i>Stemphylium lycopersici</i> on <i>Kalanchoe blossfeldiana</i> in the United States

Kalanchoe blossfeldiana Poelln., a popular ornamental plant known for its extended blooming and suitability for indoor cultivation, was observed with edema-like symptoms and necrotic blotches in a commercial greenhouse in Buncombe County, North Carolina, U.S.A., in August 2023. Affected leaves were submitted to the North Carolina State University Plant Disease and Insect Clinic for diagnosis. Fungal cultures obtained from symptomatic leaves produced conidia consistent with Stemphylium spp. Further morphological analysis and DNA sequencing of the internal transcribed spacer (ITS) region and part of the glyceraldehyde-3-phosphate dehydrogenase ( GAPDH) gene identified the pathogen as Stemphylium lycopersici. Pathogenicity tests confirmed S. lycopersici as the causative agent of the symptoms, marking the first report of this fungus causing leaf spot on K. blossfeldiana in the United States. This finding is significant in recognizing edema-like symptoms in Kalanchoe as potential indicators of S. lycopersici infection, aiding in the identification and management of leaf diseases caused by this pathogen.