Archivio Journal of Plant Pathology

Abstract:

Mango (Mangifera indica) is an important fruit crop in southern China, and gummosis is one of the most important diseases. In September 2012, symptomatic branches were collected in Panzhihua, Sichuan province. On potato dextrose agar, isolates of similar morphological characteristics were consistently recovered from surface-sterilized branch pieces. The fungus was identified as Neofusicoccum parvum based on morphology and DNA sequence comparisons (Costa et al., 2010). Conidia were hyaline, thin walled, spindle-shaped to ellipsoid, nonseptate, and ranged from 15 to 23.5 × 4 to 7 μm (average 19.5 × 5.6 μm). The rDNA internal transcribed spacer region, a partial sequence of the β-tubulin gene, and the translation elongation factor 1-α gene of one isolate (L13), showed 100% identity to N. parvum (GenBank accession Nos GU997685, HM480386 and HQ859955). Pathogenicity of three isolates was tested in three green twigs and three 3-year-old branches in mango orchards of Guangxi Academy of Agricultural Sciences, Guangxi, China.Five wounds were made for each location with a sterilized needle. Mycelial plugs were placed at wounds and then covered with parafilm. Control twigs were inoculated with uncolonized PDA plugs. Two weeks later, typical brown lesions were observed on inoculated branches, and gum exuded from infected tissues wound. No symptoms were seen on the controls. Koch's postulates were fulfilled by reisolation of N. parvum from diseased branches. In China, the disease was mainly associated with Lasiodiplodia theobromae (Li et al., 2013) and Botryosphaeria dothidea (Mo et al., 2013). To our knowledge, this is the first report of N. parvum causing mango gummosis in China.