First report of Fusarium equiseti causing leaf spots on White Ginger in Tongling, China

Ginger (Zingiber officinale Roscoe) is a commercially important crop in China, valued for its nutritional and medicinal qualities. White ginger, a unique ginger landrace, is mainly cultivated in Tongling, Anhui Province, China. From July to September 2024, leaf spot symptoms (brown necrotic spots surrounded by chlorotic halos) were observed on commercially grown white ginger plants in Tongling, with approximately 20% incidence. For pathogen isolation, symptomatic leaf tissues (2 × 2 mm) were surface sterilized with 0.5% NaClO for 1 min, rinsed three times with sterile distilled water, plated on potato dextrose agar (PDA), and incubated at 25 ℃ for 3 d. 10 morphologically similar isolates were obtained by single-spore isolation, and representative isolate TLBJY-2 was randomly selected for further characterization. TLBJY-2 exhibited whitish aerial mycelium with yellow pigmentation. Conidia produced on synthetic low-nutrient agar (SNA) at 25 °C (175 rpm, 5 d) measured 31.6-66.5 μm × 7.5-13.9 μm (n=100) with 1-5 septa. Molecular identification was conducted by sequencing the internal transcribed spacer (ITS), translation elongation factor 1-alpha (TEF1-α), and β-tubulin regions with primer pairs ITS1/ITS4, EF1-728F/EF1-986R, and Bt2a/Bt2b. Sequences were deposited in GenBank under accession numbers PX458020, PX559859, and PX559860. BLASTn analysis showed that ITS sequence shared 97.45% identity to that of Fusarium equiseti (ON495943), TEF1-α sequence shared 100% identity with F. equiseti (MK611904.1), and β-tubulin shared 99.66% identity with F. equiseti (LC648249). Combined morphological and molecular data, TLBJY-2 was identified as Fusarium equiseti. Koch’s postulates were verified via pathogenicity assays, ginger leaves were inoculated with TLBJY-2 conidial suspension (1×10 ⁶ spores/mL), with sterile distilled water-inoculated leaves as negative control. The inoculated plants were maintained in a moist chamber (>80% relative humidity) at 26 ℃ with a 12-h light cycle. After 10 d, brown necrotic spots developed on inoculated leaves, while the control leaves remained asymptomatic. F. equiseti was reisolated from symptomatic tissue，and no pathogens isolated from control leaves. F. equiseti has been reported to cause leaf spot on various hosts, including bitter gourd (Rehman et al. 2023), rocket (Garibaldi et al. 2011) and switchgrass (Jia et al. 2020). To our knowledge, this is the first report of F. equiseti causing leaf spot on white ginger in China. This finding provides a basis for developing monitoring and management strategies for ginger diseases.