Determination of fungal pathogens causing twig, shoot blight and drying on almond trees in Datça town of Muğla province

The study was undertaken to reveal the existence of the species in the Botryosphaeriaceae family and Diaporthe spp., causing twig and shoot blight, dieback and yield losses in almond trees in Datça town of Muğla province, and to identify the causal agents by classical and molecular methods. In 2018 and 2019, 78 isolates were obtained from diseased plant samples taken from 25 almond orchards in 8 villages. 36 (46%) out of the all isolates were determined as Botryosphaeriaceae and 42 (54%) was as Diaporthe spp. Pathogenicity tests revealed that all isolates were found to be pathogenic on year almond shoots (cv Nurlu). Molecular identification was carried by amplifying of genomic DNA from single hyphal tips of all isolates with the specific primer pairs of the Internal Transcribed Spacer (ITS), the Translation Elongation Factor 1-α (TEF-1α) and the β-tubulin (BT) genes using polymerase chain reaction (PCR), and sequencing of PCR products. All DNA sequences of three different genes from each isolate were analyzed and compared with those of known origin using the Basic Local Alignment Search Tool (BLAST) and the GenBank database. As a result, the 14 Botryosphaeriaceae species were identified as Neofusicoccum mediterraneum (5 isolates), Fusicoccum aesculi (Telemorph: Botryosphaeria dothidea) (4 isolates), Dothiorella iberica (Telemorph: Botryosphaeria iberica) (4 isolates), Dothiorella sarmentorum (Telemorph: Botryosphaeria sarmentorum) (1 isolate). All of these species are the first records for our country in almonds. Of 38 Diaporthe spp. isolates, 37 isolates were identified as Diaporthe amygdali and 1 isolate was Diaporthe ambigua. Although the presence of Phomopsis spp in almonds has been previously determined in our country, it has not been identified at the species level. The agent was determined molecularly and morphologically for the first time as Diaporthe amygdali with this study. As far as is known, this is the first report of D. ambigua causing twig and shoot blight on almond in the World. Morphological characteristics of 5 D. amygdali and 1 D. ambigua isolate selected as representative with Botryosphaeriaceae isolates were also determined in the study.