Anthracnose is a serious fungal disease that primarily infects strawberry roots and stolons during development. Here, 91 isolates from different areas of Zhejiang province, China, were collected. Morphological characteristics were analyzed, and a phylogenetic analysis based on multiple genes (actin, internal transcribed spacer, calmodulin, glyceraldehyde-3-phosphate dehydrogenase, and chitin synthase) was performed. We found that all of the Colletotrichum species causing strawberry anthracnose belonged to the Colletotrichum gloeosporioides complex. Among them, we identified 48 isolates of C. fructicola, 21 isolates of C. siamense, 13 isolates of C. gloeosporioides, and 9 isolates of C. aenigma. C. siamense was distributed in the central and eastern regions of Zhejiang province (Hangzhou, Jinhua, Shaoxing, Ningbo, and Taizhou). This is the first report of C. siamense causing strawberry anthracnose in Zhejiang province. C. fructicola was the most dominant species causing strawberry anthracnose in Zhejiang province. We identified the four species causing strawberry anthracnose in Zhejiang province, which will improve our understanding of the strawberry anthracnose epidemic and will benefit the development of future control measures.

Rice bakanae disease caused by Fusarium fujikuroi is one of the most famous seed borne diseases. If infected seeds are used, this disease will occur with serious impacts. Thus, a simple, reliable, specific and sensitive method for surveillance is urgently needed to screen infected seeds and seedlings at early developmental stages. In this study, a rapid and efficient loop-mediated isothermal amplification (LAMP) method was developed to detect F. fujikuroi in contaminated rice seeds and seedlings for diagnosis of bakanae disease. NRPS31 gene plays an important role in the gibberellic acid (GA) bio-synthesis of F. fujikuroi, and is not present in any other sequenced fungal genome, and thus was adopted as the target for LAMP primer design. The LAMP assay enables the fast detection of as little as 1 fg of pure genomic F. fujikuroi DNA within 60 minutes. Further tests indicated that the LAMP assay was more sensitive and faster than the traditional isolation method for F. fujikuroi detection in rice seeds and seedlings. Our results show that this LAMP assay is a useful and convenient tool for detecting F. fujikuroi, and it can be applied widely in seed quarantine of bakanae disease, providing valid data for disease prevention.

Anthracnose is one of the most common diseases in strawberry plants. Colletotrichum gloeosporioides is the major cause of anthracnose in China, including Zhejiang Province. Early, specific, reliable, and time-saving detection is urgently needed to prevent the further spread of C. gloeosporioides, guiding farmers to utilize chemicals to control anthracnose. In this study, we showed that the high resistance to pyraclostrobin, caused by a point mutation at codon 143 (GGT→GCT) in the cytochrome b gene of C. gloeosporioides was prevalent in the strawberry growing regions, and we developed a loop-mediated isothermal amplification (LAMP) assay as a detection method. Primer sets S0 and S4 could be used to specifically detect C. gloeosporioides isolates and the G143A mutations, respectively. A detection limit of 10⁻² ng (10 pg), which is at least 10-fold more sensitive than conventional polymerase chain reaction, was achieved by the LAMP assay. Here, we utilized lateral-flow devices (LFDs), nitrocellulose membranes that can absorb nucleic acids, to acquire the total genomic DNA of strawberry plants within 2 min. The LFD membranes were used as DNA templates for the LAMP assays to accurately detect strawberry plants infected with C. gloeosporioides. This diagnostic method for strawberry anthracnose was accomplished within 1 h, including the sample preparation and LAMP assays. Collectively, we developed a sensitive and practical method for monitoring C. gloeosporioides and its quinone outside inhibitor–resistant mutants. The LAMP assay for detection of C. gloeosporioides in strawberry plants has great potential for rapid strawberry anthracnose surveillance and will provide farmers with advice on preventing C gloeosporioides at the early stages of strawberry development.

Strawberry crown rot (SCR) is a serious disease that is generally referred to as seedling anthracnose due to its association with Colletotrichum spp. Presently, SCR is the main cause of death of strawberry seedlings. However, management strategies, including fungicides targeting Colletotrichum spp., have failed to obtain satisfactory results. Therefore, identifying the exact pathogen species causing SCR could guide its management. A total of 287 isolates were obtained from SCR-diseased plants. Based on the culture, morphology, and phylogenetic characteristics, the above 287 fungal isolates of SCR pathogens were identified as 12 different species, including Colletotrichum siamense, C. fructicola, Fusarium oxysporum, F. commune, F. equiseti, F. solani, F. tricinctum, Epicoccum sorghinum, Stemphylium lycopersici, Clonostachys rosea, Phoma herbarum, and Curvularia trifolii. Pathogenicity results showed that most isolates were pathogenic to strawberry seedlings and exhibited different degrees of virulence. In severe cases, poor growth on the ground, yellowing of the leaves, and even death of seedlings occurred. In mild cases, only black disease spots appeared on the stems of the strawberry seedlings, and a few withered leaves became necrotic. The inoculation experiments showed that the most virulent species were C. siamense and F. oxysporum, followed by F. equiseti, P. herbarum, Cl. rosea, S. lycopersici, and C. fructicola, which had disease incidences above 50%. E. sorghinum, S. lycopersici, Cl. rosea, P. herbarum and Cu. trifolii were reported to cause SCR for the first time herein. In conclusion, SCR is a sophisticated disease caused by a diversity of pathogenic fungi. This work provides new valuable data about the diversity and pathogenicity of SCR pathogens, which will help in formulating effective strategies to better control of the SCR disease.