Archivio Journal of Plant Pathology

Abstract:

On November 2013, light brown necrotic spots were observed on the leaves of Verbascum blattaria seedlings. Necroses reached 10 mm in diameter and dried. Eventually a hole appeared in the internal part of the necrosis. On potato dextrose agar (PDA), a fungus isolated from affected leaves produced globose or subglobose pycnidia measuring 62-164×60-163 (average 111×105 μm), containing ellipsoid, unicellular conidia measuring 2.8-4.4×1.4-2.3 ⎧m (average 3.6×1.8 ⎧m). The internal transcribed spacer (ITS) region of rDNA of the microorganism was amplified using the primers ITS1/ITS4 and sequenced (Altschul et al., 1997) (GenBank accession No. KJ192364). BLAST analysis of the 520 bp amplicon showed 100% homology with the sequence KC411473 of Phoma novae-verbascicola. Pathogenicity tests were carried out by spraying a conidial suspension of the fungus on three healthy plants of V. blattaria. Plants were kept in a humid chamber. First necrotic spots appeared 2 days after the inoculation and P. novae-verbascicola was constantly reisolated from affected leaves. P. novae-verbascicola has recently been reported on Verbascum nigrum (Garibaldi et al., 2013), while this is the first report of the pathogen on V. blattaria in Italy, as well as in the world.