Archivio Journal of Plant Pathology

Abstract:

In spring 2013, a blight was observed on plants of Nigella damascena growing in a nursery on the Agroinnova premises (Grugliasco, northern Italy). Semi-circular, water-soaked le- sions were visible on leaves and stems. Blighted leaves turned brown, withered, and matted on the surrounding foliage. Eventually, infected plants died. Rhizoctonia solani was con- sistently recovered from infected tissues. Three isolates were successfully anastomosed with R. solani isolate AG 1 (ATCC 58946) (Carling, 1996). Mycelium and micro-sclerotia ob- served in vitro were typical for Type 1-B. The internal tran- scribed spacer (ITS) region of rDNA was amplified using the primers ITS1/ITS4 and sequenced (GenBank Accession No. KF719317). BLASTn analysis (Altschul et al., 1997) of the 498 bp amplicon showed 98% homology with the sequence of R. solani HF678125. For pathogenicity tests, 60 healthy plants of N. damascena were inoculated with wheat kernel cultures (3 g/l) of a single isolate of R. solani. The first symptoms developed 3 days post inoculation. R. solani was constantly reisolated from affected plants. This is the first report of R. solani on N. damascena in Italy.