First report of fruit and leaf anthracnose caused by Colletotrichum karstii on avocado in Turkey

Avocado (Persea americana Mill.) is one of the most popular deciduous fruit crops grown in tropical and subtropical areas worldwide. Colletotrichum spp., causal agents of anthracnose, are the species commonly associated with fruit and leaf symptoms on avocado in Turkey and all over the world. Since early 2016, necrotic symptoms were detected on avocado trees grown in the Mediterranean Region of Turkey. Fungal isolates obtained from the systematic tissues were examined based on mycelial growth rate, colony colour, conidial shapes and dimensions. Morphological characteristics of the representative isolates AC1 and AC2 of Colletotrichum were similar to those described for C. karstii and the isolates were tentatively identified as Colletotrichum spp. In view of its colonies and conidia features. Morphological data were verified by multilocus phylogenetic analyses of the internal transcribed spacer (ITS) region of the nuclear ribosomal DNA; glyceraldehyde 3-phosphate dehydrogenase (GAPDH) and ACTIN partial genes from two isolates. Pathogenicity tests were conducted by inoculating healthy fruit and leaves with a spore suspension of C. karstii. Unlike the species previously recorded in Turkey, this fungus was first reported as avocado anthracnose pathogen with this study.