Archivio Journal of Plant Pathology

Abstract:

In the spring of 2016, a new disease was observed on parsley (Petroselinum crispum) plants in several fields of Hatay province (Turkey). Symptoms started as localized stem necrosis and withering of the leaves, followed by crown rotting and finally wilting of the plants. White mycelium and round to irregular black sclerotia (4.5-7.0 mm) were frequently observed on the rotted basal stems. Isolation from surface-sterlized stem and sclerotia on potato sucrose agar (PSA) consistently yielded a white mycelium with black sclerotia. For identification, the rDNA internal transcribed spacer (ITS) region (White et al., 1990) was amplified with primers ITS4- ITS5 and ITS1-ITS4, respectively. The ITS sequences (GenBank accession Nos. KX609406 and KX786156, respectively) shared 100% identity with those of Sclerotinia sclerotiorum (KU375684 and KM656466). Based on the above, the fungus was identified as Sclerotinia sclerotiorum (Mordue and Holliday, 1976). Pathogenicity tests were performed by placing mycelial plugs from a 7-day-old culture at the base of the stems of eight-week-old parsley seedlings. Plants were covered with a plastic bag and maintained at 20°C with 90% relative humidity. Within 4 days post inoculation, all inoculated plants developed symptoms similar to those observed on naturally affected plants, whereas no symptoms were observed on controls. Re-isolations from inoculated plants yielded a fungus identical to S. sclerotiorum. This disease agent has previously been reported from USA and Greece (Farr and Rossman, 2015). To the best of our knowledge, this is the first report of Sclerotinia stem rot on parsley in Turkey.