Archivio Journal of Plant Pathology

Abstract:

In the spring of 2016, in a 3 years old crop of pomegranate (Punica granatum, L.) cultivar Wonderful located in Tarquinia, central Italy, symptoms of shoot blight and plant decays appeared on about 20 plants, showing brownish bark and discoloration of the woody tissue underneath on the affected areas of the neck, trunk and branches . Isolations from the diseased wood on PDA media produced fast dark colonies producing picnidia and hyaline conidia (14-20×4–5 μm, mean 17.3×4.6 μm) with Neofusicoccum parvum features (Crous et al., 2006). The identification was confirmed by sequencing the ITS regions of two strains (ER2083-84, GenBank accession Nos. KX909938-39). The sequences showed 100% identity with many N. parvum strains deposited in NCBI and with only one base-pair difference with the ex-type CMW9081 (AY236943). Pathogenicity tests were performed inoculating both fungal strains on 10 portions each of 5-8 cm in length of one year old shoots of pomegranate (Palavouzis et al., 2015). Five days later 2-4 cm long discoloration on bark and the woody tissue underneath appeared on all branches showing a very high and fast aggressiveness of N. parvum on pomegranate. N. parvum was constantly re-isolated from the discolored tissues. Five control shoots, inoculated with PDA plugs without the fungus, did not showed any symptoms. N. parvum was previously reported as pathogen on pomegranate in Greece (Palavouzis et al., 2015) and USA (KC and Vallad, 2016). For our knowledge, this is the first report of N. parvum causing shoot blight and plant decay in pomegranate in Italy. This pathogen is of significant importance due to its aggressiveness on pomegranate, an emerging alternative crop in Italy.