AbstractIn September 2022, symptoms of leaf anthracnose were observed on desert rose (Adenium obesum) plants distributed in parks and gardens in Culiacán, Sinaloa, Mexico. Two morphotypes of Colletotrichum isolates were obtained from symptomatic tissues. Based on morphological characterization in combination with multilocus phylogenetic analyses including data from internal transcribed spacer, actin, glyceraldehyde‐3‐phosphate dehydrogenase, and β‐tubulin, and pathogenicity tests, it was confirmed that C. siamense and C. truncatum are the causal agents of the disease. This is the first report of C. siamense and C. truncatum causing leaf anthracnose in desert rose worldwide.