In this study, the fungal strain LD-11 was isolated from the infected plant of Lonicera caerulea (cv Lanjingling) collected in the horticulture experimental station of Northeast Agricultural University, Harbin, Heilongjiang Province. The strain was identified as Epicoccum nigrum by morphology, rDNA-ITS, LSU, TUB, RPB2 gene sequence amplification and phylogenetic tree construction. The experimental results showed that E. nigrum LD-11 could grow on PDA, OA and MEA medium. The optimal culture medium was OA, and the optimal culture conditions were growth temperature of 25 ℃, pH 6, carbon source is starch and nitrogen source is yeast extract, and full light conditions were conducive to mycelial growth. This study is the first time to isolate and identify E. nigrum, the pathogen of leaf spot disease in L. caerulea, which will provide an important source of pathogenic fungi for future research on control of plant disease.

Polygonatum kingianum Coll. et Hemsl., a perennial herbaceous plant belonging to the family Liliaceae, has special medicinal and dietary values. Rhizome rot, usually leading to the decrease of yield and quality, is a frequently occurred disease on P. kingianum in Yunnan Province. In this study, diseased P. kingianum samples with typical symptoms of rhizome rot were collected, and a representative fungal strain 19-1 was obtained by tissue isolation and single spore purification. The pathogenicity of strain 19-1 to P. kingianum was tested and confirmed by irrigating inoculation of plant seedlings with spore suspension (1×10⁶ spores·mL^-1). According to morphological characteristics and multigene-based phylogenetic analysis results, strain 19-1 was identified as Fusarium concentricum. This is the first report of F. concentricum causing rhizome rot on P. kingianum. Our results provide a theoretical basis for further investigation of the epidemiology and integrated control of the disease.

Pittosporum tobira is used as a evergreen plant in urban landscape. In recent years, a serious leaf disease was found on P. tobira in Chongqing, which seriously affected the ecological and landscape benefits. Disease incidence ranged from 20% to 50% in the affected fields. In this study, the pathogens of this disease were isolated and verified by Koch’s rule. The strain were identified as Colletotrichum fioriniae based on morphological characteristics and rDNA-internal transcribed space(ITS)、actin(ACT)、β-tubulin(TUB2) and glyceraldehyde-3-phosphate dehydrogenase(GAPDH) gene sequence analysis. The identification of the pathogen of anthracnose in P. tobira will provide theoretical basis for further study of disease monitoring and control.

Avena sativa is an important crop for food and feed in the world. During the investigation of oat diseases in Hohhot in 2022, a new disease was found which produced long spindle-shaped necrotic lesions on oat sheath with black spots in the center. More strains with the same colony morphology were generated from the diseased sheath tissues. One representative strain QSH2-3-2 was selected for pathogenicity test. The results show that strain QSH2-3-2 can cause necrotic spots on oat leaves and sheaths. It was identified as Didymella glomerata by morphological characteristics and multi-locus DNA sequence analysis. To our knowledge, this is the first report that D. glomerata was the pathogen of oat spot blight.

Grapevine (Vitis vinifera L.), is known as the first of the world’s four fruits, both fruit and medicinal value. Recently, ‘shine muscat’ and ‘Christmas Rose’ were premium varieties of grapevine. From May 2022 to May 2023, a fruit drop and rot disease was found on grapevine in Zhaoqin city, Guangdong province. To clarify the reason of this phenomenon, the pathogen was isolated and purified by tissue separation method, and its pathogenicity was confirmed based on the Koch’s postulates. According to morphological features and phylogenetic analysis of rDNA-ITS and EF-1α gene, the pathogen was identified as Aspergillus aculeatus. To our knowledge, this is the first report of A. aculeatus causing fruit rot on grapevine in China. The results will provide scientific basis for effective control of the disease on grapevine.

In 2023, a typical sample of root rot of Idesia polycarpa was collected in Zunyi city, Guizhou Pro-vince, China, and the pathogenic strain was obtained by tissue separation method. According to Koch’s rule, pathogenicity test, morphological characteristics and ITS, TEF1-α and TUB multigene phylogenetic analysis, the pathogen was identified as Fusarium solani. The results provided a theoretical basis for the field control of the root rot of Idesia polycarpa. This is the first time to report the root rot of I. polycarpa induced by F. solani in China.

Xinjiang wild apricot (Prunus armeniaca) has strong resistance to drought and cold. It is an important genetic resource for breeding. In 2021, twenty leaf samples of Xinjiang wild apricot were collected in the wild forests of Tianshan Mountain in YiLi, Xinjiang. Using high-throughput sequencing and RT-PCR, peach chlorotic leaf spot virus (PCLSV) and mume-associated luteovirus (MaLV) were identified. Whole genomes of these two viruses were obtained by RT-PCR and RACE. After removing poly (A), the genome of PCLSV from Prunus armeniaca (PCLSV-YX) contains 7 462 nucleotides (nts) with three overlapping open reading frames (ORFs). The genome of MaLV from Prunus armeniaca (MaLV-YX) contains 5 753 nts, and has six ORFs. Phylogenetic analysis showed that PCLSV-YX was closely related to isolates of ‘PR19-2’ and ‘TaTao’. MaLV-YX was closely related to cherry-associated luteovirus (ChALV), prunus mahaleb-associated luteovirus (PmALV), peach-associated luteovirus (PaLV) and peach-associated luteovirus 2 (PaLV2).

Morinda officinalis is a Chinese traditional herbal medicine in the family Rubiaceae. From April to June 2023, the southern blight disease occurred seriously on M. officinalis in Zhangzhou City, Fujian Province, China. The white mycelia and sclerotia of the pathogen were initially observed at the stem-soil interface of diseased seedlings, and gradually spread to neighboring plants, which resulted in the death of patches of plants. Fungal strains with same morphological characteristics were obtained from the diseased samples by using the tissue isolation method. Based on morphological characteristics, ribosomal large subunit (LSU) sequences and pathogenicity test, the representative fungal strains were identified as Sclerotium rolfsii Sacc. To our knowledge, this is the first report of S. rolfsii causing southern blight on M. officinalis, which provides important information on the pathogen for disease management.

Anthracnose is one of the most important fungal diseases that pose significant threat to the production of Yunnan red pear cultivar ‘Caiyunhong’. The disease mainly causes fruit rot, resulting in a disease incidence of more than 35% in normal conditions. The causal agent was identified as Colletotrichum fructicola based on the morphological characteristics, phylogenetic relationship inferred from ITS, ACT, TUB and CHS sequences, and the result of pathogenicity test. This is the first report of C. Fructicola causing anthracnose on ‘Caiyunhong’ fruit in China, which provides a theoretical basis for effective prevention and control of the disease.

A leaf spot of Polygonatum kingianum was found in Jianxing Town, Xinping County, Yunnan Province. Leaf infections first appeared as small, pale brown spots with a yellow haloes. The spots extended or coalesced into larger lesions, causing the entire leaf to be necrotic. The pathogen causing this disease was isolated, and its pathogenicity was tested according to the Koch' s postulates. Based on morphological characteristics and phylogenetic analysis of combined the rDNA 18S and ITS regions as well as beta-tubulin (TUB) gene sequences, the isolate DYB-2 was identified as Neopestalotiopsis acrostichi. To our knowledge, this is the first report of N. acrostichi causing the leaf spot on Polygonatum kingianum in the world.

To clarify the species and biological characteristics of the pathogenic fungi that cause root rot of Ficus virens in Hainan Province, pathogenic fungi were isolated from diseased tissue and basidiocarps collected from the root of the diseased tree of Ficus virens in March 2022 by tissue separation method. The pathogenic bacteria causing the root rot disease were identified through pathogenicity determination, combing with morphology identification and molecular identification. The effects of pH, temperature, medium and light on mycelium growth under different treatments were measured by cross crossing method. The results showed that the isolated pathogenic ganoderma strain was the pathogen causing the root rot of Ficus virens. After morphological characterization and jointly phylogenetic tree construction based on rDNA-ITS, rDNA-LSU and rDNA-SSU, the pathogen strain was identified as Ganoderma tropicum. The biological characteristics showed that the optimal medium was PDA medium, the optimal pH was 7.0, the optimal light condition was total darkness, and the optimal growth temperature was 32 ℃.It will provide scientific theoretical basis for the diagnosis and control of this disease.

In recent years, the planting area of Prunus serrulata in Henan Province has been increasing, and the disease problem is becoming more and more serious. A canker disease that infects the branches of P. serrulata has been observed in many areas; it causes brown canker tissue on the shoots, twigs and kills the branches. To clarify the pathogen causing shoot canker of P. serrulata in Henan Province, isolates were obtained from diseased shoots and identified based on the morphological and molecular biological methods. In this study, a total of 21 strains with the same morphological characteristics were obtained and Koch’s postulates was verified. According to its morphological and molecular biological characteristics, the pathogen causing shoot canker of P. serrulata in Henan Province was finally identified as Diaporthe eres. This is the first report of D. eres responsible for P. serrulata shoot canker. The optimum growth temperature of D. eres was 25 ℃, and the optimum pH was 6, the optimum carbon source was sucrose, the optimum nitrogen source was yeast powder.

From 2020 to 2022, a new disease, basal stem rot of Achyranthes bidentata was prevalent in the field in Wuzhi county, Jiaozuo city, Henan province. The incidence of severe disease plot was over 90%, that seriously affected the yield and quality of A. bidentata. Tissue isolation and culture method was used to isolate and purify the pathogen from disease samples of A. bidentata with the typical symptoms of stem rot. Based on the morphological identification, sequence analysis of ITS and TEF-1α, and pathogenicity assays, the pathogen were identified as Rhizoctonia solani, and belonged to anastomosis subgroup (AG)-4-HGI. This is the first report of R. solani AG-4-HGI causing basal stem rot on A. bidentata in China, the results of this study could provide useful guidance for the effective prevention and control of A. bidentatae basal stem rot.

Mycoleptodiscus terrestris is a pathogen on many legumes, but there are very few reports about it occurring on peas. In May 1989, the pathogenic fungus producing black microsclerotia was isolated from diseased roots of pea in Dingxi city, Gansu province. Due to limited knowledge and the lack of important literature at that time, the fungus was named as Burgoa pisi in 1998. In May 2018, several fungal strains with the same morphological characteristics as B. pisi were isolated from diseased pea roots and hypocotyls in Huining county, Gansu province. The optimum mycelial growth temperature of tested strains was 25-30 ℃. When cultured on PCA medium at 30 ℃ for 14 d, the strains produced abundant of microsclerotia, the microsclerotia were nearly spherical to irregular, (104.5-567.2) μm × (95.5-343.3) μm, and there were 0 to dozens of setae on the sclerotial surface, the setae were multicellular and columnar, the basal cells were colorless or pale, and the terminal cell was black thick-walled (sheath-like), straight, slightly curved or short forked. However, when on PDA and PCA media at 25-30℃ for 21 days, no conidia produce, and they also failed to induce conidia by soybean leaves inoculation in vivo. BLASTn analysis showed that the sequences of strain TCD-11 (GenBank accession No. ITS: OL981504; LSU: OL981961) and TCD-28 (GenBank accession No. ITS: OL981505) had a 99.45% similarity in the ITS region and 100% identity in the LSU region with M. terrestris ex-type strain CBS 231.53 (GenBank accession No. ITS: MK487754.1; LSU: MK487730.1). In the combined phylogenetic tree of rDNA-ITS and LSU sequences, tested strains TCD-11 and TCD-28 were clustered with M. terrestris strains in same group. Pathogenicity test showed that the tested strains had aggressive pathogenicity to the root and epicotyl of pea (Pisum sativum) (included edible pod pea and edible seed pea), the infected roots and hypocotyls showed extensive brown to dark brown spots; they had weak pathogenicity to broad bean (Vicia faba) of Fabaceae, only small restricted black necrotic spots were formed at the inoculation site. The pathogen was reisolated from all infected pea and broad bean plants and had the same morphology as isolates TCD-11 and TCD-28, fulfilling Koch’s postulates. According to morphological and molecular biological characters, tested strains are identified as M. terrestris, and B. pisi in essence is a synonym of M. terrestris.

Paris polyphylla var. yunnanensis (Franch) Hand.-Mazz is an important cash crop in Yunnan ethnic minority areas. In 2022, we discovered a new type of leaf spot disease in the Lijiang planting area, which can damage the entire growth period of the crop. The typical symptoms in the field were spots(diameter 2.4-6.7 mm) on the surface of the disease leaves, the leave become brown and necrosis in later stage thus resulting in serious economic losses. We isolated pathogenic bacteria by monosporophyte isolation,and identified by morphological observation and polygenic phylogenetic analysis, and its pathogenicity was verified using Koch’s rule.The final identification results showed that the pathogen was a new species of Cercospora and was named Cercospora polyphylla x.he & P. W. Yang, sp.11 according to the binomial nomenclature.This is the first report of Paris polyphylla var. yunnanensis (Franch) Hand.-Mazz leaf disease caused by C. polyphylla in China, and this study will provide a theoretical basis for the epidemic and comprehensive prevention and control of the disease.

Verticillium wilt of Chinese cabbage is an emerging disease in Qinghai Province. The symptoms of verticillium wilt is discoloration of the vascular bundle of roots, blackening and discoloration of stems or leaf veins which may extend to the whole leaves and death in severe case. This study isolated and cultured 24 strains from 10 Chinese cabbage samples in Qinghai Province and detected the strains with morphological observation, DNA sequence analysis, and pathogenicity test to determine the pathogen. Morphological observation showed that the strain QH-87 grew very slowly on potato dextrose agar medium with a large number of black microsclerotia( (5.8-27.8) μm × (35.3-356.8) μm), and the length to width ratio was 2.3-25.6. Conidia were transparent and cylindrical and its size was (2.1-5.4) μm × (4.5-11.9) μm. Chlamydospores and dormant hyphae were not observed. The fungus was verified as Verticillium longisporum lineage A1/D1 according to the results of ITS, ACT and EF sequencing. The pathogenicity test showed that strain QH-87 could infect Chinese cabbage and caused discoloration and wilt. In a word, the pathogen was identified as V. longesporum lineage A1/D1. It is the first report of verticillium wilt of Chinese cabbage in Qinghai province, and V. longisporum lineage A1/D1 is first reported on Chinese cabbage in China.

In the autumn of 2019, a new leaf spot disease was discovered on Zizania latifolia plants in two locations, Langya in Jinhua, and Daji in Lishui, Zhejiang Province. We isolated the pathogen using tissue separation method, and identified it as Epicoccum sorghinum through multiple methods, including morphological observation, biological identification and pathogenicity test. Besides, to prevent the effect of E. sorghinum on the yield and quality of Z. latifolia, 12 chemical fungicides were screened. Among these, prochloraz showed the best inhibitory effect on the pathogen. Additionally it had the least side effect on the growth of Ustilago esculenta, another mutually beneficial organism associated with Z. latifolia. So prochloraz can be used as an effective fungicide for the disease management. This study provides a scientific basis for the identification and understanding the leaf spot disease in Z. latifolia. It offers insights into the selection of chemical fungicides for its control, which is valuable for agricultural and disease management.

In recent years, apple diaporthe neck and root rot has become one of the most important limiting factors for the development of apple production in Yunnan Province. In this study, the typical disease samples were collected and the fungal isolate M2g7-1 was obtained by tissue separation approach. The purified culture M2g7-1 was preliminary determined belonging to Diaporthe spp. based on the morphological features of colony, pycnidia, cirrus, two forms of conidia. The pathogenicity of M2g7-1 was further validated on apple young branches to fulfill the Koch's law. The taxonomic of pathogen M2g7-1 has been further determined with combining molecular phylogenetics. The phylogenetic tree was created with the data set of sequences from the internal transcribed spacer (ITS) of ribosomal DNA, the histone H3 (HIS) gene, the translation elongation factor 1-alpha (TEF) gene, and the beta-tubulin (TUB) gene. Based on morphological and molecular biology analysis, the pathogen M2g7-1 was finally identified as Diaporthe eres. This is the first report of D. eres as the pathogen of apple diaporthe neck and root rot. The research results provide a theoretical basis for the epidemic research and comprehensive control of this disease.

Bletilla striata is one of the genuine medicinal materials in Guizhou, and its planting area ranks first in China. In 2022, the leaf blight of Bletilla striata occurred in Guizhou Academy of Agricultural Sciences with a large area and was serious. In this study, the pathogenic fungus was isolated from the leaves with obvious symptoms, which was identified to be Rhizoctonia solani AG1-IB based on the results of morphological identification, ITS sequence analysis, and hyphal anastomosis. To our knowledge, there have been no reports on the isolation of R.solani AG1-IB from Bletilla striata in China as so far. This is the first report and the results will provide theoretical reference for effective control and further research of leaf blight on Bletilla striata.

Citrus is one of the most important fruits in China and is cultivated extensively in southern China. Fusarium fujikuroi has been reported to cause diseases on various plants excluding citrus worldwide. In this study, by using tissue separation method, 23 Fusarium-like isolates were isolated from diseased citrus leaves from eight different citrus planting areas in Hubei province. STJ-4 was selected as a representative isolate for further analysis, which included analyses of morphological characteristics, partial sequences of ITS, EF-1α, and RPB1 genes, phylogenetic trees based on the three genes and pathogenicity. Results showed that the STJ-4 isolate was identified as F. fujikuroi, which is the first report of F. fujikuroi causing leaf rot disease on citrus. Our study is important for developing the prevention strategies against F. fujikuroi in the future.

Brown rot symptoms on fruit of Lucuma nervosa were observed in Guangxi South Subtropical Agricultural Science Research Institute. The samples were collected from the field, the pathogen was isolated by tissue isolation, and its pathogenicity was verified by the Koch′s rule. The pathogen was identified as Lasiodiplodia pseudotheobromae by combining morphological characteristics and ITS-TUB-RPB2-TEF1 sequence analysis. This is the first report of Lasiodiplodia pseudotheobromae causing brown rot on Lucuma nervosa fruit in the world.

As an important ornamental plant, hollyhock (Alcea rosea L.) plays an important role in landscape architecture. In May 2023, a new rust disease on A. rosea was observed in Guiyang, Guizhou Province. Rust infected various parts of A. rosea and seriously reduced the ornamental value. In this study, the teliospores were collected from the diseased leaves of A. rosea. Based on the morphological characteristics and phylogenetic analyses of internal transcribed spacer (ITS) and large subunit (LSU) sequences, the rust pathogen was identified as Puccinia modiolae. This is the first report of P. modiolae causing rust disease on A. rosea in China. These findings will promote further research on rust disease on A. rosea and provide a scientific basis for its control.

As a famous fruits of the tropics and subtropics,the overall growth of Hylocereus polyrhizus have been seriously affect by a mature stem blight disease found in the regions of H. polyrhizus plantations in Danzhou city,Hainan province of China in 2022. It caused extensively grayish-white blight of the diseased stems. The pathogen isolated from the diseased plants was identified as Diaporthe passiflorae,based on pathogenicity test,morphological traits and phylogenetic analyses of multi-loci (ITS,TUB2,CAL,TEF1-α and HIS3). The results provide a theoretical basis for the field control of stem blight of H. polyrhizus.

Cherry tomato (Solanum lycopersicum var. cerasiforme) is an important crop in Hainan Province, and its production is seriously damaged by viral diseases. To identify the viruses infecting cherry tomato, LncRNA sequencing was performed using leaf samples from diverse geographical locations with typical viral symptoms. The virome of cherry tomato comprises eight viruses─ageratum yellow vein virus (AYVV), cucumber mosaic virus (CMV), southern tomato virus (STV), tobacco mosaic virus (TMV), tomato chlorosis virus (ToCV), tomato mosaic virus (ToMV), tomato mottle mosaic virus (ToMMV) and tomato yellow leaf curl virus (TYLCV). The PCR detection results of 234 cherry tomato leaf samples from nine cities and counties indicated that the dominant viruses are TYLCV (69.23%), ToCV (49.57%) and ToMMV (35.47%), followed by STV (23.50%), ToMV (17.52%), CMV (17.52%), AYVV (16.24%) and TMV (10.68%). The ratio of mixed virus infection was 81.62%. Complete genomes of two AYVV isolates (AYVV-tomato-LS1 and AYVV-tomato-LS2) and one TYLCV isolate (TYLCV-tomato-LS) in the genus Begomovirus were obtained using PCR with back-to-back primers. The pairwise comparison of genomes of AYVV-tomato-LS1 and AYVV-tomato-LS2 were 98.98% nucleotide identical to each other, sharing their maximum nucleotide identities at 92.71% and 92.81% with AYVV-SY08 (GenBank accession no.: KC810890), and were phylogenetically closely related to the AYVV isolates from diverse hosts from Hainan. TYLCV-tomato-LSs shared their maximum nucleotide identities at 96.52% with TYLCV-HNLS (GenBank accession no.: MK908814), and were phylogenetically closely related to the TYLCV isolates from diverse hosts from Hainan, followed by Capsicum annuum isolates from Spain (GenBank accession no.: AJ489258). Our findings provide support for sustainable control strategies for cherry tomato virus disease in Hainan, China.

White root rot is one of the most important root diseases of grape. From 2021 to 2022, the symptoms of white mycelium on the surface of grape roots were observed in several grapevines in Shanxi Province, China, with the incidence of 26.74%. Symptomatic root samples were collected and taken back to the laboratory to isolate the fungi. In this study, twenty strains were obtained by single hyphal purification. Based on the morphological characteristics and multi-gene (ITS, LSU and TUB2) phylogenetic analysis, these strains were identified as Rosellinia necatrix. To confirm the pathogenicity, the inoculation was performed by adding wheat seeds colonized by R. necatrix in the soil. The results showed that R. necatrix was pathogenic to the grape. To our knowledge, this is the first report of R. necatrix causing white root in Shanxi province, China.

Gummy stem blight, usually seen on the stems, leaves and fruits, is one of the most serious threats to production of pumpkin (Cucurbita moschata Duch.) in Hebei with reduction of the quality and heavy losses in yield. The pathogenic organisms of the disease were still obscure because several fungal species with most similar morphology were reported to be the causative agents. A fungal pathogen NG2023021301-4 was isolated from the diseased tissue and purified by single-spore isolation. According to morphological characteristics and combinatory phylogenetic analysis of ITS region, TUB gene sequences, the pathogen was identified as Stagonosporopsis caricae. To our knowledge, this is the first report of S. caricae causing verticillium wilt of pumpkin fruits.

The fungal strain 98180-8 was isolated from the maize of Malaysian containers. The pathogenicity of the isolated fungus was confirmed in inoculating tests. To elucidate the strain, morphological observation, PCR detection and ITS sequence analysis were used in this study. Taken all, the strain 98180-8 was identified as Stenocarpella maydis, an ear rot pathogen of maize.

Ficus hirta (vahl) is a valuable medicinal plant as well as edible plants in southern China. In 2022, a new stem blight disease was observed to infect Ficus hirta (vahl) in Danzhou of Hainan province. The incidence of disease reached 47.5% in fields. In order to clarify the pathogen of Ficus hirta stem blight disease, ten isolates with the same morphology were isolated from blight tissue by using a conventional tissue separation method. MA2, a representative strain with excellent growth, was selected for pathogenicity test on Ficus hirta plants, observation of morphological characteristics, sequence analysis on ITS, TUB and TEF, and phylogenetic tree construction. The results showed that morphological characteristics of the isolate MA2 was similar to that of Lasiodiplodia pseudotheobromae. The isolate MA2 was clustered into one clade in phylogenetic tree with L. pseudotheobromae. The above results indicated that the stem blight of F. hirta was caused by L. pseudotheobromae. This is the first report of a stem blight disease on F. hirta in China was identified as L. pseudotheobromae.

In 2021, typical leaf samples of Rosa chinensis black spot disease were collected from the South Tropical Garden in Kunming, Yunnan Province, China, and a strains were obtained by tissue isolation method. According to Koch's rule, morphological characteristics and phylogenetic analysis of ITS, TEF1 and TUB gene sequences, the pathogen was identified as Gnomoniopsis rosae. This is the first report that G. rosae caused R. chinensis black spot disease in China.

Foxtail millet (Setaria italica (L.) Beauv.), a novel model species in C₄ gramineae crops, plays a principal role in food security in Africa and Asia and in the adjustment of the crop planting structure in China. It is sensitive to continuous cropping, which is a serious constraint to the production and the quality. Root rot di-sease is typical for the diseased foxtail millet in continuous cropping fields. In this study, a fungus was obtained from the rotten root millet samples and grouped according to their colony morphology, namely, YDSi-1, YDSi-2 and YDSi-3. According to pathogenic tests fulfilling the Koch’s postulate, YDSi-3 showed a strong pathogenicity for root rot of foxtail millet. Based on morphological and molecular identification, YDSi-3 was identified as Fusarium oxysporum. This is the first report of F. oxysporum causing root rot of foxtail millet in China, and will provide a theoretical basis and technical support for the control on the continuous cropping of foxtail millet in the future.

During the disease survey in spring of 2023, watermelon in Shandong province and Zhenjiang province displayed silver grey and irregular mottled symptoms on leaves. In order to identify the virus, ten samples including the leaves, stem and the young fruit were collected, and total RNA was extracted from each sample. The RT-PCR method was used to amplify the conserved partial N gene sequence encoded by watermelon silver mottle virus (WSMoV) S RNA, and the partial N gene was cloned and sequenced. Sequence analysis showed that the sequence identity of WSMoV-Zhejiang and WSMoV-Shandong isolates with WSMoV-Thailand SN858 and WSMoV-Yunnan Banna-2011 isolates was over 99.0%. Furthermore, phylogenetic analysis showed that the partial N gene clustered with the Thailand and Yunnan-Banna-2011 isolates. The results showed that watermelon silver mottle virus (WSMoV) occurred in watermelon in Zhejiang and Shandong provinces. This is the first time the virus has infected watermelon in Zhejiang and Shandong provinces.

In recent years, pear anthracnose has become one of the major pear diseases in Dangshan County of Anhui Province and its surrounding areas. In order to identify the pathogens of ‘Dangshan Su’ pear anthracnose, the diseased samples were collected from Dangshan County and the pathogens were isolated, purified, and identified through morphology and molecular biology analysis. In this study, the pathogenicity of the pathogens was assayed by using the fruits and leaves of ‘Dangshan Su’ pear as materials. All these confirmed that the pathogens were mainly Colletotrichum fructicola and C. siamense. The specific detection primers Cf-F/Cf-R were designed according to part of the mRNA sequence of C. fructicola, which could specifically detect C. fructicola from similar strains and diseased tissues.

Weigela florida is one of the main early spring shrub in north China and plays an important role in the construction of modern urban parks. In August 2022, a severe outbreak of leaf spot was observed on W. florida in the flower garden of Daoxianghu park, Beijing. The fungus was isolated by tissue separation method, and its pathogenicity was confirmed based on the Koch’s postulates. According to morphological features and phylogenetic analyses of rDNA-ITS, Alt a 1, GAPDH, endoPG, EF1-α and RPB2 genes, the pathogen was identified as Alternaria alternata. To our knowledge, this is the first report of A. alternata causing leaf spot on W. florida in China, which will provide scientific basis for effective control of the disease on W. florida.

Watermelon is an important economic crop and is widely cultivated all over the world. Seedling disease of watermelon caused by Rhizoctonia spp. can lead to seedling death. In this study, 149 Rhizoctonia isolates were isolated from the diseased seedlings of watermelon, which were collected from Beijing municipality, Heilongjiang and Jilin provinces, and Ningxia Hui autonomous region of China from 2014 to 2019. Based on morphological characteristics and sequence analysis of internal transcribed spacer of ribosomal DNA (rDNA-ITS), the 149 isolates were assigned to ten anastomosis groups (AGs) or subgroups, namely AG-1-IB, AG-1-IC, AG-2-1, AG-4HGI, AG-4HGII, AG-4HGIII, AG-5, AG-A, AG-B(o) and AG-Fa, with R. solani AG-4 (HGI, HGII, and HGIII) being predominate. All tested Rhizoctonia isolates were pathogenic to watermelon seedling. The virulence of multinucleate Rhizoctonia (MNR) was significantly higher than that of binucleate Rhizoctonia. Among the MNR, R. solani AG-4HGI, AG-4HGII, and AG-4HGIII were the most aggressive on watermelon seedling, and the average disease incidence and disease index of watermelon seedling caused by the three subgroups were 97.92%, 96.15% and 99.14%, and 76.16, 63.43 and 72.01, respectively. To the best of our knowledge, it is the first report of AG-1-1B, AG-1-1C, AG-2-1, AG-5, and AG-B(o) causing disease on watermelon seedling in China and perhaps worldwide.

Rhus chinensis ,also known as Chinese gallnut tree is an important economic tree species in China. In recent years, anthracnose symptoms were found on the branches and rachises of Rhus chinensis at several planting located in Wufeng Tujia Autonomous County, Hubei Province. Initially the brown spots were discovered on the infected tree. As the spots gradually expanded, irregular in shape, multiple spots could be united together into a big one, and the color of the spots gradually turned dark brown to black. Finally, the diseased branches broke off, the leaves and the galls on branches became wilt. Ten isolates were obtained from branches samples and eight of them were identified as Colletotrichum nymphaeae by morphology and multilocus phylogenies from combined datasets of ITS, Tublin, Actin, Gadph, Chs. The assay of Koch’s postulates confirmed that C. nymphaeae was the causal agent of Rhus chinensis anthracnose. To our knowledge, this is the first report of C. nymphaeae causing Rhus chinensis anthracnose in China.

Powdery mildew is a common disease on Coreopsis lanceolata, which affects the growth and deve-lopment of the plant and reduces its ornamental value. From 2022 to 2023, powdery mildew occurred seriously on Coreopsis lanceolate in Beijing. In this study, typical morphological characteristics of the pathogenic isolates were analyzed, and a phylogenetic tree was constructed based on the ITS sequence. The results showed that the isolates were identified as Podospaera fusca. This is the first report of Coreopsis lanceolata powdery mildew in Beijing, which will contribute to the control of powdery mildew on Coreopsis lanceolata.

A cosmetic defect on fruits of citrus Orah ((Citrus tangerina × C. sinensis) × C. tangerina) and Shatangju (Citrus reticulata Blanco cv. Shatangju) outbreaks in Southern China recently. As necrosis of outer layer cells in the green pericarp of fruits, the symptoms looked like ringworm or tinea, the name of “white scaled blotch” was given. However, as the etiology of the disease has not been determined, the strategy for prevention and control of this disease was confusion. In this study, field investigation was token and samples were collected from more than 10 orchards in the Guangxi and Guangdong provinces during 2020 to 2022. The pathogen was isolated on the infected pericarp, and its pathogenicity was confirmed with Koch’s postulates. Based on morphology and phylogenetic analysis of thecombined sequence data of LSU, ITS and rpb2, the pathogen was identified as Zasmidium fructicola. The determination of etiology lays a foundation for the study of epidemiology and to guide prevention and control of this disease.

Trunk canker disease is one of the most common diseases of Carya cathayensis, causing huge economic losses. In May 2021, typical trunk canker symptoms were observed on hickory in Lin'an City, Zhejiang Province. Three fungal isolates (ZQ3, ZQ5 and ZQ12) were obtained by tissue isolation and purified using single-spore isolation method. Species identification was performed by morphological traits and sequences analyses of internal transcribed spacers (ITS) of rDNA, TEF1-α, and LSU gene, and all the fungal isolates were identified as Fusarium oblongum. To fulfill the Koch's postulations, pathogenicity assay was carried out on phloem of the hickory stems. The all tested isolates were pathogenic to hickory, proving that F. oblongum was a pathogen inciting hickory trunk canker disease. This is the first report of F. oblongum causing trunk canker on Carya cathayensis in China.

Fungal disease is an important factor restricting the high and stable yield of soybean. In order to clarify the taxonomic status of pathogenic isolates SoyITS1 and SoyITS12 isolated from the diseased soybean roots with the symptoms of root rot, the two isolates were identified on the basis of morphological traits and sequence analyses of translation elongation factor 1-α (EF1-α) and RNA polymerase II beta subunit (RPB2). The results showed that the colonies of isolates SoyITS1 and SoyITS12 were milky white when they were cultured on PDA medium. After 7 d of culture on CLA medium, the conidia were falciform with blunt apical cells and slightly crooked base cells, with 3 - 4 septa, the size of which was (20 - 40) μm× (3.5 - 6.8) μm (n = 50). BLAST sequence comparison showed that the consistency between strains SoyITS1 and SoyITS12 and Fusarium falciforme was 86.7% - 98.8%. In the two monogenic and polygenic phylogenetic trees, SoyITS1 and SoyITS12 strain was clustered in the same evolutionary branch as F. falciforme. Strain SoyITS1 and SoyITS12 were identified as F. falciforme based on morphological characteristics, homology analysis and phylogenetic tree analysis.