Archivio Journal of Plant Pathology

Abstract:

In late August 2013, leaf spot symptoms were first noticed on Virginia creeper [Parthenocissus quinquefolia (L.) Planch], an ornamental cum medicinal plant of vitaceae family, in the Forest Park, Luoyang City of Henan Province, China. Symptoms appeared as small circular brown dots on the leaves, gradually expanding into circular or irregularly-shaped yellow-brown to dark brown spots with raised margins and black dots in the center of the lesions. A fungus was carefully isolated from the leaf spot and cultured on potato dextrose agar, which produced dark brown colonies. Pycnidia were brown, ovoid, 13.3 μm in diameter. Conidiophores were cylindric and colorless, 8.1-10.l × 3.8-4.0 μm. Conidia (n = 50) were 18.1-20.8 × 2.5-4.2 μm, 2 to 4 septate, with apical cell hyaline, other cells pale brown. One eccentric pedicel, hyaline, 8-10.6 × 1.2 μm. Apical appendages 1 to 4, 13.3-16.0 × 1.2 μm, unbranched. Based on the isolate characteristics (Sutton, 1980; Barnett and Hunter, 1998), the fungus was subsequently confirmed as Bartalinia robillardoides by DNA sequence analysis of internal transcribed spacer, which was 100% identical to other known B. robillardoides isolates (GenBank Accession No. KF656706.1). To confirm pathogenicity of the fungus, ten surface disinfected healthy leaves of Virginia creeper were inoculated with a fresh conidial suspension (40 μl, 5 × 106 conidia/ml) of B. robillardoides at 26°C. Leaf necrosis symptoms appeared on the inoculated leaves within 7 days. The same fungus was successfully reisolated from the lesions, confirming Koch’s postulates, whereas, control plants showed no symptoms. To our knowledge, this is the first report of B. robillardoides infecting P. quinquefolia in China.