First report of Geotrichum candidum causing sour rot of peach in China

Peach (Prunus persica L. Batsch) is one of the most important fruit crops in China (Wang et al. 2011). Yangshan Town Jiangsu Province four major peach producing areas China, with a growing area 2,000 ha (Tian 2018). During June 2020, postharvest disease presenting brown necrosis and rot occurred on peaches Town. The estimated damage was more than 10% total harvest. symptoms included soft rot, lesion appeared sunken, accompanied sour odor white mycelia. Twelve representative symptom were sampled for pathogen isolation. Pieces (about 5 mm × mm) from edge symptomatic fruits dissected surface disinfected (3% NaClO 10 s 75% ethanol 30 s), then rinsed three times distilled water, dried sterile filter paper transferred to Potato Dextrose Agar (PDA) media plates supplemented 150 ng/mL streptomycin sulfate. incubated at 28 ℃ 3 days. Forty-eight isolations obtained isolates single-spored. All presented white, flat, milky yeast-like colonies radial Hyphae under microscope septate, branched, disarticulating into arthroconidia measuring 3.39 9.27 2.05 7.71 μm. morphological characteristics are consistent Geotrichum candidum (De Hoog 1986). Internal transcribed spacer (ITS) 18s nuclear ribosomal small subunit (SSU) 48 amplified sequenced using primers ITS5/ITS4, NS1/NS4 molecular identification (Schoch 2012). resulted sequences showed no difference among all isolates. Alignment by blastn sequence ITS SSU 100% (accession number. GQ376093) 99.7% identical KY977411.1) candidum, respectively. number MW493646) MW493648) submitted GenBank. Commercial ripe size about 15 cm used pathogenicity test. Peaches ethanol, wound 4 diameter depth made each fruit. Ten inoculated μL (1×105 spores /mL) isolate suspension. Another ten water as control. individually ℃and relative humidity 85%. After days, large scale pits every inoculated, diseased Town, while non-inoculated control observed. re-isolated identified again sequencing SSU. tests conducted times. Considering evidence, we G. candidum. This has been reported cause kiwifruit, strawberry, melon other (Alonzo 2020; Cheng Halfeld-Vieira 2020). To our knowledge, this first report causing which may great loss industry China.