Q. H. Zhu

Bottle gourd [Lagenaria siceraria (Mol.) Stand] is a widely cultivated succulent crop species. In December 2022, a serious bottle gourd disease occurred in the protected vegetable planting base of Xingguo County, Ganzhou City, Jiangxi Province, China, with 85% of the 2,100 plants having gray mold disease-like symptoms, including gray spots on the infected fruit. They quickly expanded at suitable temperature and humidity, forming a gray mold layer with inward depressions, which spread to the fruit stem causing watery rot, and the flesh turned black and started to rot. To isolate the pathogen, fruits of the diseased plants were surface-disinfected with 75% ethanol for 30 s, immersed in 0.1% HgCl2 for 1 min, rinsed thrice with sterile water, and cultured on a potato-dextrose agar (PDA) medium at 28°C. Mycelia from the diseased tissue were subcultured on fresh PDA medium to obtain pure cultures. After incubation at 25°C for 7 days, olive-green colonies (~2.5 mm·d-1) developed. Cultures developed numerous elliptical and limoniform conidia measuring 2.69~9.79 μm to 2.10~5.92 μm (average 5.62×3.12 μm) (n=20). The morphological characteristics of the pathogen resembled those of Cladosporium spp. Fungal genomic DNA was extracted, and the internal transcribed spacer (ITS), partial translation elongation factor-1 alpha (TEF-1α), and actin (ACT) regions were amplified with primers ITS1/4, TEF-728F/986R, and ACT-512F/783R, respectively, and sequenced (Bensch et al. 2012; Jo et al. 2018). Basic Local Alignment Search Tool analysis (BLAST) revealed that the ITS (accession no. OQ186729), ACT (OQ240962), and TEF-1α (OQ240963) sequences of isolate hjt4 shared the highest similarity (99-100%) with those of Cladosporium tenuissimum (accessions no. OM232068, OM256530, OM256526) (Duccio et al. 2015). A phylogenetic tree of the isolate hjt4 and its close relatives within Cladosporium was constructed using the MEGA X neighbor-joining method. The pathogen was identified as C. tenuissimum based on morphological and molecular characteristics. A specimen (JXAU-H2022982) was deposited at the Herbarium of the College of Agronomy, Jiangxi Agricultural University. To confirm its pathogenicity, seven-day-old healthy bottle gourd fruits were disinfected with 75% ethanol, 1 mm-deep wounds were made with sterilized scalpels, and the plants were inoculated with PDA plugs (0.8 cm in diameter) containing actively growing mycelia of isolate hjt4. Plants inoculated with sterile PDA plugs served as controls. Each group contained three fruits, and the experiment was performed in triplicate. All fruits were incubated in a biochemical incubator at 28°C. After 3 days, the fruit surface shrank, and the flesh turned to a black colour and rotten, which rapidly spread to the branches. Control fruits did not develop any symptoms. Reisolated colonies showed the same morphological traits as those of the inoculation isolates, whereas no target colonies were isolated from the control fruits. The pathogen was previously reported to cause leaf blight disease in Coriandrum sativum (Zhou et al. 2022) and sooty spots on Cape gooseberry (Miyake et al. 2022), among others. To our knowledge, this is the first report of gray mold disease caused by C. tenuissimum on bottle gourd in China. The findings provide an important foundation for monitoring and controlling the spread of this disease.

Chilli pepper is one of the most important and widely cultivated pepper types in China. It has high nutritional and economic value. Capsicum frutescens L. is one of the chilli pepper types in production. In October 2022, a new disease showing blight of the entire chilli pepper plant was observed in Nanchang City, Jiangxi Province. The fungal isolates consistently obtained from the diseased samples were identified as Diaporthe caryae C. M. Tian & Qin Yang based on morphological characteristics, pathogenicity test and phylogenetic analysis of four genes, including internal transcribed spacer region (rDNA‐ITS), translation elongation factor 1‐alpha gene (TEF1), beta‐tubulin gene (TUB2), and calmodulin (CAL). Although other Diaporthe species have been reported as pathogens of peppers previously, to our knowledge, this is the first report of D. caryae causing stem blight of pepper in the world. D. caryae was reported to be able to infect various fruit trees such as kiwifruit, peach, pear, and pecan, resulting in kiwifruit rot, peach constriction canker, pear shoot canker, and pecan dieback, respectively. The host range of D. caryae has expanded from fruit trees to vegetable crops.

Rohdea japonica, known as Japanese sacred lily, a perennial herb in the family Asparagaceae, is an important ornamental plant in China (Hinkley 2006). In May 2022, at the campus of Jiangxi Agricult...