Watermelon is an economically important crop in China and is commonly affected by Alternaria-like leaf blight that can result in significant economic losses. In this study, 830 Alternaria isolates, recovered from symptomatic watermelon leaves, were identified based on morphological traits, pathogenicity, and multilocus sequence analyses of glyceraldehyde-3-phosphate dehydrogenase (GAPDH), histone 3 (HIS3), the internal transcribed spacer of ribosomal DNA (rDNA ITS), and the RNA polymerase II second largest subunit (RPB2). Watermelon isolates grouped to five Alternaria species and one unclassified Alternaria species. They were A. tenuissima, A. alternata, A. cucumerina, A. infectoria, A. gaisen, and Alternaria sp. Notably, A. tenuissima was the most prevalent (73.5%) of the six isolated species, followed by A. alternata (25.0%), A. cucumerina (1.1%), Alternaria sp. (0.2%), A. infectoria (0.1%), and A. gaisen (0.1%). Pathogenicity tests demonstrated that all six Alternaria species could produce brown necrotic lesions on detached leaves of watermelon. The average disease incidence (75.1%) and average disease index (60.8) of watermelon resulting from inoculation of leaves with A. cucumerina were significantly higher than levels resulting from A. alternata (52.9% and 37.2) and A. tenuissima (47.5% and 30.8). Inoculation with Alternaria sp. resulted in a disease incidence (70.0%) and disease index (51.5), which were lower than those of A. cucumerina. The disease incidence and disease index in watermelon leaves inoculated with the one isolate of A. infectoria and the one isolate of A. gaisen present in the inoculated leaves were 28.9% and 16.4, and 48.9% and 31.4, respectively. Results of the study indicate that Alternaria species associated with watermelon leaf blight in China are more diverse than that has been previously reported. This is the first report globally of A. infectoria, A. gaisen, and an unclassified Alternaria species as causal agents of leaf blight on watermelon.

Potato (Solanum tuberosum L.), a worldwide, staple food crop, is susceptible to postharvest rots caused by a variety of fungal pathogens, including Fusarium spp., Alternaria spp., Phytophthora infestans, Helminthosporium solani, Rhizoctonia solani, and Colletotrichum coccodes. Rots resulting from infections by these pathogens cause a significant reduction in potato quality and marketable yield. Importantly, some of these decay fungi also produce mycotoxins that represent a potential risk to human health. In the present review, an overview and discussion are provided on the epidemiology and pathogenesis of decay fungi, especially Fusarium spp., that include recent data derived from genomic and phylogenetic analyses. The biosynthesis and functional role of fungitoxic metabolites such as trichothecene mycotoxins and fusaric acid, produced in rotted potatoes are also reviewed. Advances in pre- and postharvest measures for rot management, especially eco-friendly methods including physical control, biological control, the use of natural compounds, and other agricultural management practices are also reviewed. Lastly, novel approaches to control potato dry rot such as the use of mycoviruses and CRISPR technology are highlighted.

Fusarium crown rot (FCR) is one of the most important soilborne diseases affecting wheat production. To investigate the diversity of the pathogens causing this disease, 199 diseased wheat samples were collected from 13 cities in Shandong province. In total, 468 isolates were obtained, and from these isolates, 11 Fusarium species were identified based on phylogenetic analyses with the translation elongation factor-1α (TEF-1α), RNA polymerase II largest subunit (RPB1), and RNA polymerase II second largest subunit (RPB2) gene sequences. Of these Fusarium isolates, 283 were identified as Fusarium pseudograminearum and the remaining isolates were identified as Fusarium graminearum (n = 113), Fusarium sinensis (n = 28), Fusarium acuminatum (n = 18), Fusarium incarnatum (n = 13), Fusarium ipomoeae (n = 5), Fusarium flocciferum (n = 3), Fusarium proliferatum (n = 2), Fusarium asiaticum (n = 1), Fusarium culmorum (n = 1), and Fusarium oxysporum (n = 1), suggesting that F. pseudograminearum is the dominant pathogen of FCR of wheat in Shandong province. Pathogenicity tests demonstrated that all 11 Fusarium species could cause typical symptoms of FCR on wheat seedlings. The results of the study indicate that a greater diversity of Fusarium species can cause FCR of wheat in Shandong province than that has been previously reported. This is the first report in the world of Fusarium incarnatum, Fusarium ipomoeae, and Fusarium flocciferum as pathogens causing FCR in wheat.