Characterization and epidemiology of C olletotrichum acutatum sensu lato ( C . chrysanthemi ) causing C arthamus tinctorius anthracnose

In 2012, C olletotrichum isolates were collected from field‐grown safflower ( C arthamus tinctorius ) crops in central Italy from plants exhibiting typical anthracnose symptoms. C olletotrichum isolates were also collected from seed surfaces and from within seeds. The genetic variability of these isolates was assessed by a multilocus sequencing approach and compared with those from Colletotrichum chrysanthemi and Colletotrichum carthami isolates from different geographic areas and other C olletotrichum acutatum sensu lato ‐related isolates. Phylogenetic analysis revealed that all of the strains isolated from C . tinctorius belonged to the species described as C . chrysanthemi , whereas all of the strains belonging to C . carthami had been isolated from Calendula officinalis . Phenotypic characterization of isolates was performed by assessing growth rates at different temperatures, morphology of colonies on potato dextrose agar ( PDA ) and the size of conidia. All C . chrysanthemi isolates from safflower had similar growth rates at different temperatures, comparable colony morphologies when grown on PDA and conidial sizes consistent with previously described C . chrysanthemi isolates. Pathogenicity tests were performed by artificially inoculating both seeds and plants and confirmed the seedborne nature of this pathogen. When inoculated on plants, C . chrysanthemi caused the typical symptoms of anthracnose on leaves. This is the first record of this pathogen on C . tinctorius in Italy, and it presents an updated characterization of C olletotrichum isolates pathogenic to safflowers in E urope.