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During the years 2017 and 2018, leaves and stems with dark brown lesions containing hypophilic telia surrounded by chlorotic halos were collected from Sphaeralcea angustifolia plants located in Axapusco, State of Mexico. Based on the morphological characteristics, the fungus Puccinia sherardiana was identified. Uredinal stage was not detected during the observation period. Verification of the identity of the fungus was carried out by means of a phylogenetic analysis with part of a sequence of the 28S gene of ribosomal DNA. Pathogenicity tests were performed on S. angustifolia plants by inoculating teliospores. The inoculated plants developed symptoms and signs 15 days after inoculation, beginning with the presence of eruptive aecia in the epidermis of the host and later the formation of telia, completing Koch’s Postulates. The fungus P. sherardiana was previously described as a rust with a microcyclic life cycle on species of the genera Alcea, Malvastrum, Sidalcea and Sphaeralcea, belonging to the Malvaceae family; however, in this study the pathogen behaved differently. P. sherardiana will continue to be studied to determine if its life cycle is demicyclic in Mexico. |
