Morphological and molecular characterization of a novel Pestalotiopsis trachycarpicola, causing Garden Croton leaf spot in Iran

In the spring of 2021, leaf spot disease symptoms were observed in the garden croton (codiaeum variegatum) plants in one of the ornamental plant greenhouses of mahallat county, markazi province, iran. to identify the causal agent of the disease, infected plant leaves sampled and then were transferred to the mycology laboratory and nine fungal isolates were recovered. the fungal isolates were characterized based on the morphological features and molecular data using the combined sequences of the internal transcribed spacer (its) regions and the translation elongation factor 1-alpha (tef) gene for a representative isolate ut2022. according to the morphology and phylogenetic analysis, the isolate ut2022 was identified as pestalotiopsis trachycarpicola. the pathogenicity of the isolate ut2022 was performed on healthy and growing leaves of the c. variegatum plants. inoculated leaves showed leaf spot symptoms 14 days after the inoculation, while the leaves of the control plants were symptomless. to complete koch’s postulate, p. trachycarpicola was re-isolated from the newly produced leaf spots. based on the bibliography, p. trachycarpicola is reported as a new taxon for fungi of iran, as well as p. trachycarpicola is reported as the causal agent of the leaf spot symptom of the c. variegatum in the world.