First report of Pilidiella granati causing postharvest fruit rot on pomegranate in southern Italy

In 2015, rot symptoms were observed during storage on pomegranate fruit (Punica granatum L.) cvs Wonderful and Mollar de Elche from a packinghouse in Apulia (Southern Italy). Symptoms, observed on 26% of fruit, consisted of circular brownish-yellow lesions, beginning in the crown area and quickly expanding to entire fruit, with softening of the tissues including arils. Tissue portions were cut from surface-sterilized fruit and incubated on semi-selective PDA at 28±1°C in the dark. Colonies were white to creamy, leathery, and covered by abundant dark-greenish- brown to black spherical pycnidia (80-140 μm in diameter) with thin membranous walls. Hyphae were septate, and conidia hyaline, one-celled, 10-17.5×2-5 μm, ellipsoid to fusiform, straight or slightly curved. These characteristics corresponded to Pilidiella granati (Saccardo) (syn. Coniella granati Sacc.) Petr. & Syd.). For molecular confirmation, fungal DNA was amplified using universal primers ITS5/ITS4. BLAST analysis of the 506 bp amplicon (GenBank accession No. KU821701) showed 100% identity with other P. granati ITS sequences. For pathogenicity tests, surface-sterilized fruit of both cvs were wounded (5×5 mm), inoculated by a mycelial plug and incubated as reported above. Sterile plugs were used as controls. Lesions were visible after five days only on inoculated fruit. The re-isolated fungus corresponded to P. granati, which was reported as pomegranate postharvest rot agent in Spain (Palou et al., 2010) and recently associated with a crown rot in Italy (Pollastro et al., 2016). To our knowledge, this is the first report of P. granati rot on harvested pomegranate fruit in Southern Italy that might represent a serious threat for marketing of this promising crop.