To clarify the symptom diversity and the causal pathogen of maize white spot in Liaoning Province, typical symptomatic leaves were collected from multiple regions in 2025 for systematic observation of symptoms, and isolation and identification of the pathogen. Field symptoms were classified into five types: white spot, brown spot, stripe spot, blighted spot, and cloudy spot. The dominant fungal isolates obtained from each symptom type through tissue isolation shared identical morphological characteristics, consistent with Setophoma zeae-maydis. Five representative isolates, one from each symptom type, were selected for pathogenicity tests. All five isolates induced the same typical white spot symptoms on maize leaves, rather than reproducing the five distinct field symptom types. Molecular identification based on ITS and LSU sequences confirmed that all five isolates shared 100% sequence identity with S. zeae-maydis. These findings elucidate the symptom-pathogen relationship of maize white spot in Liaoning Province and provide a basis for field diagnosis and disease management.

To identify the causal agent of a blueberry fruit disease characterized by shrunken and withered fruits with orange-red conidial masses in Hezhang County, Guizhou Province, fungal isolates were obtained from symptomatic fruits using tissue isolation method. Representative isolates were identified based on morphological characteristics and a multi-locus phylogenetic analysis (ITS, glyceraldehyde-3-phosphate dehydrogenase, chitin synthase, actin, and β-tubulin). Pathogenicity was confirmed through in vitro fruit inoculation assays. The results showed that the isolates induced typical anthracnose symptoms on healthy blueberry fruits, and the same fungus was re-isolated from the lesions, fulfilling Koch's postulates. Phylogenetic analysis indicated that the two representative isolates (JZB330473, JZB330474) clustered within Colletotrichum godetiae with 100% maximum likelihood bootstrap support. Combined with morphological characteristics, they were identified as C. godetiae. This is the first report of C. godetiae causing blueberry fruit anthracnose in China. Our findings provide a scientific basis for the diagnosis and targeted control of blueberry anthracnose in Guizhou Province and enrich the known species diversity of Colletotrichum associated with blueberry anthracnose in China.

Leaves showing symptoms of tobacco white leaf spot were collected from the tobacco field of ‘Yunyan 97’ in Ankang City, Shaanxi Province, China. Forty-three strains were isolated by the tissue isolation method. Twenty-seven strains showed morphological characteristics similar to the representative isolate BXAK1, accounting for 62.8%, and their pathogenicity was verified by Koch's postulates. Strain BXAK1 produced pycnidia and cleistothecia under UV-induced culture on OA plates containing sterilized tobacco stalks, and the morphology of conidia or ascospores was consistent. There was no color change on OA medium by the NaOH spot test. The strain cultured on PDA medium was greatly influenced by light conditions and continuous light was the most suitable for its growth. According to the analysis of the phylogenetic tree constructed by ACT gene sequence, strain BXAK1 and Stagonosporopsis inoxydabiliscbs CBS 425.90 were clustered into one branch. Based on the above results, the pathogen causing tobacco Stagonosporopsis leaf spot was identified as S. inoxydabilis. The new pathogen of tobacco Stagonosporopsis leaf spot disease was clarified, which provided theoretical basis for the occurrence, epidemic and comprehensive control of the disease.

In 2025, a previously unreported bacterial leaf spot disease was observed on soybean (Glycine max) during the middle and late growth stages in the northern spring soybean-growing region of China. Disease incidence exceeded 80% in severely affected fields, resulting in considerable economic losses. Bacterial strains were isolated from symptomatic leaves, and pathogenicity was confirmed by Koch’s postulates. The pathogen was identified as Pseudomonas amygdali pv. tabaci by phylogenetic analyses based on 16S rDNA gene, gyrB, rpoB, and rpoD sequences. To our knowledge, this is the first report of soybean wildfire caused by P. amygdali pv. tabaci in China. These findings provide a basis for future studies and management of this disease.

Myrica rubra (Lour.) S. et Zucc. is an important fruit tree in China, particularly in Zhejiang Province. However, branch canker disease has been increasingly prevalent in major production areas in recent years, severely affecting the healthy development of the M. rubra industry. In this study, branches showing typical canker symptoms were collected, potential pathogenic fungi were isolated and identified, and multigene phylogenetic analysis based on five gene loci (act, ITS, LSU, rpb2, tub2), morphological characterization, and pathogenicity tests were conducted. The results confirmed that Cytospora myrtagena is the causal agent of branch canker disease in bayberry, representing the first report of C. myrtagena infecting M. rubra. These findings provide a theoretical basis for the prevention and control of branch canker disease and offer important practical guidance for field management.

Osmanthus fragrans Lour. is a widely cultivated ornamental tree species in China and it is also a well-known aromatic and medicinal plant. In the People's Park, Zijingshan Park and Henan Academy of Agricultural Sciences in Zhengzhou City, this plant was found to develop canker on branches with a disease incidence rate of 80%-100%. A fungal species was isolated using tissue isolation methods. Pathogenicity was confirmed by inoculating a representative isolate onto healthy branches of O. fragrans. The pathogenic fungus was identified as Nothophoma quercina by using morphological characteristics and multiple gene sequence analysis of ITS, β-tubulin, and RPB2, which is a closely related genus of Phoma. This fungal pathogen produced olive-green colony on PDA and formed spherical pycnidia with one-cell ellipsoidal conidia of (2.74-4.07) μm×(3.56-7.20) μm in size. This study is the first report of N. quercina causing branch canker of O. fragrans in China.

Pinus bungeana, a unique and endangered coniferous tree in China, possesses significant ecological and ornamental value. A needle segment spot disease observed in Hancheng, Shaanxi Province, severely threatens the growth of P. bungeana. The causal pathogen was isolated from infected needles using the tissue isolation method, and the pathogenicity was confirmed according to Koch's postulates. Based on morphological characteristics and phylogenetic analysis of concatenated ITS, TEF1-α, and β-tubulin sequences, the pathogen was identified as Fusarium acuminatum. In vitro toxicity assays revealed that all six tested fungicides inhibited the mycelial growth of F. acuminatum to varying degrees. Among them, three triazole fungicides (tebuconazole, difenoconazole, and hexaconazole) demonstrated strong inhibitory efficacy, with EC₅₀ values of 0.206, 0.324, and 0.677 μg·mL^-1, respectively. To our knowledge, this is the first report of F. acuminatum causing needle segment spot on P. bungeana. The results of this fungicide screening provide a basis for developing precise disease control strategies.

In May 2024, a novel leaf spot disease was observed on Cayratia japonica in planting areas of Jinhua City, Zhejiang Province, China. Initial symptoms appeared as small water-soaked lesions that developed into irregular brown necrotic spots with distinct yellow halos, ultimately causing leaf perforation. The disease incidence ranged from 35% to 60%. The causal agent was isolated using the tissue isolation method, and its pathogenicity was confirmed by satisfying Koch's postulates. Based on morphological characteristics, cultural traits, physiological and biochemical profiling, and molecular identification (including phylogenetic analysis of 16S rDNA, purH, and rpoB sequences), the pathogen was identified as Enterobacter mori. To the best of our knowledge, this is the first report of E. mori causing leaf spot on C. japonica worldwide. This study provides a foundation for early diagnosis and integrated management of this emerging disease.

The red celery planted in the experimental field of the Inner Mongolia Autonomous Region Agriculture and Animal Husbandry Technology Promotion Center exhibited leaf yellowing and mottling symptoms. Through high-throughput sequencing analysis of the infected samples, celery gammacytorhabdovirus 1 (CelGCRV1) was detected. The complete genome sequence of CelGCRV1 was obtained using RACE technology combined with RT-PCR and was named 23IM_RC1 (GenBank accession number: PQ552775). The sequence was blasted against the GenBank database of NCBI using the BLASTn program, and one published CelGCRV1 sequence (GenBank accession number: BK064347) was found. In this study, 160 previously published L protein sequences of Rhabdoviruses were collected. Then, their phylogenetic relationship with the L protein of the 23IM_RC1 virus was analyzed. The results showed that 23IM_RC1 belongs to the Gammacytorhabdovirus genus. Further analysis indicated that 23IM_RC1 has the closest genetic relationship with the isolate from Zhejiang, China. The complete genome nucleotide homology between 23IM_RC1 and 18 isolates of Gammacytorhabdovirus ranged from 43.1% to 99.6%. No recombination events were found in the 23IM_RC1 genome using the seven algorithms provided by RDP4. This paper is the first report of CelGCRV1 detection in China. The results of this study provide basis for the development of CelGCRV1 detection techniques and the study on its pathogenic mechanisms.

Ditylenchus destructor is a significant agricultural quarantine nematode in China, which is capable of causing substantial yield reductions in potatoes. As Inner Mongolia is a major potato-producing region in China, identifying the haplotype of D. destructor infecting potatoes is critical for the quarantine and control of this pathogen. Nematodes solated from dry rot potato tubers, collected in Saihan District, were characterized morphologically, identified molecularly and verified pathogenicity. The morphological characteristics of the nematode population in Saihan District closely resembled those of D. destructor. The pathogenicity experiment showed that potatoes inoculated with the Saihan population developed specific symptoms of stem nematode infection after 40 days. Amplification using D. destructor-specific primers produced a band of approximately 375 bp, which confirmed the identity of the nematodes as D. destructor. The phylogenetic tree constructed based on rDNA-ITS sequences demonstrated that the nematode population clustered with the A-type of D. destructor. Comparative analysis revealed that the Saihan population shared the highest sequence similarity (99.71%) with an A-type population from Chifeng City, Inner Mongolia, among other potato-infecting A-type populations. In conclusion, the pathogen causing potato dry rot in Saihan District was identified as A-type of D. destructor. These finding provided a theoretical basis for developing improved quarantine and control strategies against D. destructor in this region.

During an investigation of pests and diseases affecting garden plants in Chongqing’s urban areas, severe leaf spot disease exhibiting typical anthracnose symptoms was observed on hydrangeas, resulting in extensive leaf yellowing and wilting. Two morphologically distinct Colletotrichum strains, designated ELXQ and BLXQ, were isolated and purified from symptomatic leaves of Hydrangea japonica. Pathogenicity tests confirmed both strains as causal agents, fulfilling Koch's postulates. Based on integrated morphological characteristics and multi-locus phylogenetic analyses using the ITS, GAPDH, CHS and ACT gene regions, strain BLXQ was identified as Colletotricum gloeosporioids and ELXQ as C. fioriniae, respectively. Among the seven broad-spectrum fungicides tested, 25% pyraclostrobin and 45% prochloraz showed the strongest inhibitory effects against strains BLXQ and ELXQ, with EC₅₀ values of 2.2874 mg·L^-1 and 2.7105 mg·L^-1, respectively. These were followed by 50% carbendazim and 25% pyraclostrobin, which exhibited EC₅₀ values of 4.3385 mg·L^-1 and 2.9817 mg·L^-1 against the two strains, respectively. These three fungicides were identified as promising candidates for controlling hydrangea anthracnose. Our findings provide crucial information on pathogen identification and fungicide selection, establishing a basis for developing effective management strategies against this disease.

Panicummiliaceum L., a minor cereal crop, is widely cultivated in arid and semi-arid regions of China. In 2024, a leaf blight disease was observed in this crop in Shanxi Province. Initial symptoms included fusiform lesions on the sheaths and elliptical lesions with irregular concentric rings on the leaves, both of which eventually causing leaf blight. Based on morphological characteristics, multilocus phylogenetic analysis (ITS, GAPDH, and EF-1α), and pathogenicity assays, the pathogens were identified as Bipolaris yamadae. Our study provides a scientific basis for further research on the prevention and control of this disease.

To identify the pathogen causing malformation and chlorosis symptoms in common lilac (Syringa vulgaris L.), a complete genome sequence of lilac leaf chlorosis virus China isolate (LLCV-China) was determined by deep sequencing of a small RNA library constructed from LLCV-infected samples using rapid amplification of cDNA ends (RACE) PCR. RNA1-RNA3 of LLCV-China were determined to be 3 434 nt, 2 773 nt and 2 267 nt in length and shared 44.22%-66.15%, 33.78%-62.74% and 34.96%-59.84% sequence identity with the members of the genus Ilarvirus, respectively. Phylogenetic analyses based on its four open reading frames (ORFs) indicated that LLCV-China clustered together with the previous reported LLCV isolates. This is the first report of a complete genome sequence of LLCV from China, which provides a foundation for the future research of LLCV.

In China, Hydrangea species have long been cultivated as ornamental plants. Recently, a severe leaf spot disease affected Hydrangea macrophylla plants in Chengdu, Sichuan Province, and caused a significant decline in their economic value. In this study, the pathogen was isolated and identified through morphological observation, sequence analysis of the small subunit (SSU) and D2-D3 expansion regions of the large subunit (LSU) of ribosomal RNA, and verified by Koch’s postulates, which confirmed Aphelenchoides fragariae as the causative agent of the disease. This finding marks the first documented case of A. fragariae causing leaf spot disease on hydrangeas in China. The results provided a scientific foundation for developing effective control strategies against this pathogen-caused hydrangea leaf spot disease.

Meloidogyne hispanica is one of the most important invasive plant root-knot nematode (RKNs). In this study, we present the de novo sequencing and assembly of its complete mitochondrial genome (mitogenome). The circular mitogenome spans 17 572 bp with an A+T content of 83.43% and encodes 36 genes: 12 protein-coding genes (PCGs), 22 transfer RNA genes (tRNAs), and two ribosomal RNA genes (rRNAs). PCGs mostly use standard ATN and TAN start/stop codons. Analysis of Ka/Ks ratios across the 12 PCGs within the genus Meloidogyne revealed distinct evolutionary signatures: COX1 exhibited the slowest evolutionary rate, whereas ND2 and ND6 showed accelerated evolution. Comparative genomic analysis revealed that the intergenic region between ND4 and ATP6 is the determinant of mitochondrial genome size in Meloidogyne species. The maximum-likelihood phylogenetic analysis based on the concatenated nucleotide sequences of the 12 PCGs from 23 species in the Nemata was performed. The phylogenetic analysis revealed that M. hispanica clustered within a distinct monophyletic clade of Meloidogyne species, with Meloidogyne oryzae exhibiting the greatest genetic divergence from other Meloidogyne species. This study provides the first mitochondrial genome sequence of M. hispanica. By integrating phylogenomic inference and evolutionary rate analysis, our findings establish a foundational dataset for further evolutionary study of Meloidogyne.

Fresh samples of Lagerstroemia indica showing flat stem and leaflet symptoms indicative of phytoplasma infection were collected in Xuzhou, Jiangsu Province. Transmission electron microscopy revealed spherical phytoplasma particles (500-800 nm in diameter) within the phloem of infected stems. Nested PCR amplification targeting the phytoplasma 16S rRNA gene yielded approximately 1.2 kb fragments from all 10 sampled specimens. The associated phytoplasma was designated Lagerstroemia indica fasciation phytoplasma (LiFP). Nucleotide sequence identity analysis indicated that the 16S rRNA gene of L. indica fasciation phytoplasma shares 99.92% identity with Paulownia witches′-broom phytoplasma strain sdyz (GenBank accession No. KP662133.1) and SDJX (OP107405.1) strain. Phylogenetic trees reconstructed from 16S rRNA showed that L. indica fasciation phytoplasma is closely related to members of group 16SrI. Furthermore, RFLP analysis and similarity coefficient calculations confirmed its classification into 16SrI-B subgroup.

Root rot disease has become increasingly severe on cowpea plants in Hainan Province, China in recent years due to the hot and humid climate conditions. To identify the causal agent of the disease, cowpea plants with typical symptoms of root rot were collected from Sanya City, Hainan Province in June 2023. A total of 20 single-spore fungal isolates with similar morphology were obtained, and their pathogenicity was confirmed by artificial inoculation test. Based on morphological characteristics and phylogenetic relationship inferred from rDNA-ITS, TEF1-α and RPB2 sequences, these isolates were identified as Corynespora cassiicola. This is the first report of cowpea root rot caused by C. cassiicola in China.

Fagus longipetiolata Seem. is one of the main tree species for afforestation in high-altitude regions of China, possessing significant economic and ecological value. In May 2023, a leaf spot disease was observed at the F. longipetiolata-planting areas in Huangping County, Guizhou Province. The disease was manifested as brown spots with dark brown margins on leaves. To identify the causative agent of the disease, we performed tissue isolation to get potential pathogens and further confirmed their pathogenicity following Koch′s postulates. The isolates were identified as Alternaria alternata based on morphological characteristics and phylogenetic relationship inferred from rDNA-ITS, TEF-1α, and GAPDH sequences. This is the first report of A. alternata causing leaf spot on F. longipetiolata in China. The results provide a basis for the development of effective prevention and control strategies for this disease.

Apple rubbery wood virus 1 (ARWV-1) is an important apple virus, related to apple rubbery wood disease, and belongs to genus Rubodvirus, family Phenuiviridae. In this study, the nested PCR amplification primer combinations were designed referencing the Small (S) fragment of the ARWV-1 genome. In the first round amplification, the annealing temperature of primer AR-1S-F1R1 was 55 ℃. In the second round amplification, the annealing temperature was 60 ℃; the dosage of dNTP (2.5 mmol·L^-1 each) and primer (10 μmol·L^-1) was 0.3 μL. The detection sensitivity of AR-1S-F1R1-F2R2 were 10^-5. The detection rates of the nested primer combinations for 36 parts of apples were100%, and the rate for 150 field samples was 13.5 times higher than that of regular PCRs. The detection efficiency of nested PCR was better than that of regular PCR. The establishment of ARWV-1 nested PCR detection technology provides important technical support for the prevention and control of apple rubbery wood disease in China.

Turfgrass is an essential component of urban greening, sports, and relaxation, whose health directly affects the aesthetics of cities and the quality of residents’ life. The leaf spot caused by Alternaria leads to the leaf yellowing of turfgrass and thus finally dying away, which threatens its health of turf and reduces the value of ornamental application. In this study, nine isolates of Alternaria were isolated from the diseased leaves of turfgrass, which were collected from turf of urban green space, golf course, and soccer field. Based on morphological characteristics and molecular method, the nine isolates were assigned to two species, namely A. alternata (four strains) and A. tenuissima (five strains). All the nine isolates could infect the leaves of Poa pratensis, causing leaf spot disease, with the average disease incidence and disease index of 100% and 14.32, respectively. This is the first report about Alternaria causing leaf spot disease on turfgrass.

Sugar beet is one of the important sugar crops, providing significant value on agricultural production in China. The seedling stage healthiness guarantees the productivity of sugar beets. During May 2020 and 2021, a new leaf spot disease was observed in sugar beet seedlings of paper-pot nursery seedling cultivation area in Ulanqab, Inner Mongolia Autonomous Region. A fungal strain and four bacterial strains were isolated and purified from the symptomatic seedling samples and the pathogenicity were verified by Koch′s postulate. The morphologic characters and phylogenetic reconstruction indicated that the novel seedling disease was caused by the co-infection of Pseudomonas syringae and Fusarium oxysporum. In this study, we identified the causal agents of the seedlings stage disease in Ulanqab, which provides theoretical guidance for prevention and control of seedling diseases and reducing the loss of sugar beet.

The Orah mandarin, a thick-skinned citrus variety originating from Israel, has been introduced to several citrus-producing regions in southern China in recent years. In March 2022, black rot symptoms were observed on approximately 10% of Orah mandarin fruits in a storage facility in Wuhan City, Hubei Province, China. The fungus was isolated from the diseased tissue and identified based on morphological characteristics and multi-gene sequence analyses, including the large subunit (LSU), the nuclear ribosomal internal transcribed spacer (ITS), beta-tubulin (β-tubulin), and RNA polymerase II (rpb2) genes. The causal organism was identified as Stagonosporopsis pogostemonis, a fungal species not previously reported on Orah mandarin. Pathogenicity tests fulfilled Koch’s postulates, confirming S. pogostemonis as the pathogen responsible for the black rot symptoms. This is the first report of S. pogostemonis causing black rot disease in citrus fruits worldwide.

A leaf blight disease seriously affecting the quality and yield of Alpinia katsumadai Hayata was discovered at the Academy of Tropical Agricultural Sciences Nursery Agriculture Base, Chinese Academy of Tropical Agricultural Sciences, Danzhou City, Hainan Province. The pathogen AH-1, which caused the disease, was isolated from the disease lesion of Alpinia katsumadai Hayata. Based on both morphological characteristics and phylogenetic analysis of multiple gene sequences, including β - tubulin (TUB2), internal transcriptional spacer (ITS), and ribosomal subunit (LSU), this pathogen was further identified as the species Neoscirrhia mateuciicola. The study of this pathogen provides a basis for the prevention and control of Alpinia katsumadai Hayata leaf blight.

During a survey in 2020, cucumber plants in Shandong province displayed yellowing and chlorotic symptoms on leaves. In order to identify the pathogen, eight samples were collected, and PCR was used to test for virus species. The full-length genomic sequences of DNA-A and DNA-B of SLCCNV (squash leaf curl China virus) were cloned, and their phylogenetic relationships were also analyzed. The analysis confirmed the presence of both CCYV(cucurbit chlorotic yellows virus) and SLCCNV in the collected samples. The DNA-A of the SLCCNV genome was 2 735 nt in length, while the DNA-B of SLCCNV was 2 717 nt (GenBank accession no. OM258181 and OM258182). Further results showed that the DNA-A and DNA-B formed an independent cluster and were mostly related to the SLCCNV isolates that reported in China. This is the first systematic report of SLCCNV infecting cucumber in China.

Wheat stripe rust is one of the airborne fungal diseases that threaten the safety of wheat production. The emergence of new races of Puccinia striiformis f. sp. tritici (Pst) leads to the loss of the resistance of wheat cultivars, and causes disease epidemics due to its rapid accumulation and spread in oversummering variable areas of the pathogen. Qinghai Province is an important oversummering epidemic area of wheat stripe rust in China, in which the causal agent Pst can infect Berberis to complete sexual cycle. Therefore, determining the proportion of Pst infecting Berberis plants in Qinghai Province under natural conditions is very important to understand the roles of alternative host Berberis being attacking by the sexual reproduction of Pst and providing inoculum causing stripe rust on wheat. In this study, 1860 aecial samples collected from Berberis growing in main wheat-planting areas in Qinghai Province from 2022 to 2024 were used to determine Pst using combined methods of inoculation on susceptible wheat cultivar and detection with the Pst-specific molecular markers. As a result, the isolation rates of Pst from aecial samples in the three years were 2.72%, 4.10% and 2.38%, respectively, with an average of 3.07%. The detection rates based on molecular markers were 23.22%, 27.42% and 20.48%, respectively, with an average of 23.71%, with the highest isolation rate and detection rate in 2023. Therefore, in Qinghai Province Pst can infect the alternative host Berberis to complete sexual reproduction under natural con-ditions, with a high proportion. The results provide a clue for understanding the generation of new races of Pst and the origin of inoculum causing wheat stripe rust. Thus, it is necessary to strengthen effective management of sexual reproduction of Pst in the oversummering variable area in Qinghai Province for the prevention and control of wheat stripe rust in the local and national areas.

Root rot was found in main durian-planting areas in Hainan Province. The symptoms include root and root crown rot, which resulted in reduced tree vigor (leaf yellowing, leaf drop), branch wilt, even the death of entire tree. This causes serious economic losses to durian production. To identify the causal agent of this disease, diseased root samples of durian trees were collected from Sanya, Ledong, Lingshui and Baoting in Hainan Province from 2023 to 2024, and tissue isolation method was used to obtain potential pathogens. Based on morphological characteristics, phylogenetic relationship inferred from rDNA-ITS, Ypt1, β-Tubulin and EF-1α, and the result of pathogenicity test, the pathogen was identified as Phytophthora palmivora. This is the first report of durian root rot caused by P. palmivora in China.

A stem rot disease was found on Ficus virens and Ficus concinna in Hainan Province, China, in 2022. The diseased plants showed symptoms of sparse crowns with chlorotic leaves and dead branches, and even died when severely damaged. Yellow brown semi-circular basidiocarps were usually observed at the base of diseased trees in rainy and humid seasons. To identify the causal agent of the disease, conventional tissue isolation methods was adopted for pathogen isolation from diseased samples, and the representative strains HNQHHGR20221003001 and HNDXXYR2023051804 were used for pathogenicity test and morphological and molecular identification. Based on morphological characteristics, phylogenetic relationship inferred from rDNA-ITS, SSU and LSU, and the result of pathogenicity test, the pathogen was identified as Ganoderma australe. This is the first report of stem rot caused by G. australe on Ficus microcarpa in China. The results provide a basis for the control of the disease.

In the newly built apple orchard in Shilin County in central Yunnan, the incidence rate of apple root rot exceeded 20% and had been increasing by more than 10% annually, resulting in significant financial losses for fruit farmers. This study aims to clarify the pathogen and whether there are new pathogenic bacteria, so as to develop comprehensive prevention and control technologies and curb the epidemic of the disease. Samples of typical diseased plants were collected and subjected to tissue isolation methods for the isolation of pathogenic bacteria. The pathogenicity of the bacteria was confirmed through inoculation tests, and their preliminary classification was based on morphological characteristics. Furthermore, molecular biology identification was conducted using multilocus genes including internal transcribed spacer (ITS), β-tubulin (β-TUB), and histone H3 (HIS3). Through a combination of morphological and molecular biology identification methods, the pathogen responsible for apple root rot was conclusively identified as Ilyonectria vredehoekensis. This discovery represents the first report of apple root rot caused by I. vredehoekensis, laying a foundation for developing epidemic monitoring and integrated control technologies to manage this disease outbreak.

In 2021, a tea plant leaf spot disease was found in the Jin Xuan tea plants( Camellia sinensis cv.Jinxuan). A representative strain was isolated from the diseased leaves according to Koch’s postulates. The isolates were further identified as Cladosporium cladosporioides based on morphological characteristics and phylogenetic analysis with internal transcribed spacer region (ITS) and β-Actin gene. The results showed that the pathogen causing the disease was Cladosporium cladosporioides. This is the first report of Cladosporium cladosporioides in tea plants in China

Morus alba is an important economic tree. In 2023, a new foliar disease of mulberry tree occurred in Longchuan of Yunnan Province, China. Irregularly shaped brown spots were exhibited on the surface of infected leaves, with small black dots on the adaxial surfaces of blotches. In pathogenicity test, small brown lesions were observed surrounding the inoculation sites of wounded leaves after 5 days, resembling the symptoms that occurred in the field. The conidia of the pathogen are fusiform, erect or slight curving, with 4 septa, 1-4 hyaline apical appendages and a size of (22.11-26.58) μm×(4.62-6.31) μm long. Based on morphological characteristics and multi-locus phylogenetic analysis involving internal transcribed spacer (ITS), translation elongation factor 1 gene (tef1) and beta tubulin gene (tub2), and pathogenicity test result, the pathogen of mulberry leaf spot was identified as Pestalotiopsis camelliae. To our knowledge, this is the first report of P. camelliae causing leaf spot on mulberry tree in China.

Soft rot of konjac was found in main konjac-planting areas in Shangluo region of Shaanxi Province, China. The symptoms include petiole and corm rot, which result in leaf yellowing and wilt, even the death of entire plant. This has caused serious economic losses to konjac production. To identify the causal agent of this disease, petiole and corm samples of konjac with typical symptoms of soft rot were collected from Shanyang, Danfeng and Shangnan counties in Shangluo region from 2023 to 2024, and tissue isolation method was used to obtain potential pathogens. Based on morphological and biochemical characteristics, phylogenetic relationship inferred from full genome and the 16S rRNA sequence, and the result of pathogenicity test, the pathogen was identified as Raoultella ornithinolytica. This is the first report of konjac soft rot caused by R. ornithinolytica in the world.

Areca palm latent totivirus 1 (APLTV1) is a newly discovered virus that infects areca palms in Hainan Province. The objective of this study is to reveal the molecular evolutionary characteristics of the APLTV1 population in this province. Thirty-one randomly selected APLTV1-positive samples were subjected to genome sequence amplification, followed by sequence and phylogenetic analyses. The complete sequences of the 31 APLTV1 isolates from Hainan were all determined to be 4764 nucleotides in length, sharing a high sequence identity of 98.02% to 99.12% with the representative XS-3 isolate of APTLV1. Within the APLTV1 genome, two open reading frames (ORFs) were identified encoding the coat protein (CP) and the RNA-dependent RNA polymerase (RdRp), respectively. Negative selection was found at the majority of polymorphic sites within the RdRp and CP genes, whereas positive selection was found exclusively at polymorphic sites within the CP gene. Phylogenetic analysis revealed that all isolates of APLTV1 could be separated into two distinct clades. The results obtained from this study provide valuable insights into understanding the epidemiology and molecular variation of APLTV1.

In order to clarify the occurrence of root rot disease in Yunnan apple producing areas, the types of pathogens and the existence of new pathogens, this study aims to investigate the presence of root rot pathogens in Yunnan apple orchards and identify any potential new pathogens. Disease samples were collected from apple producing areas in Yunnan. The pathogens were obtained by tissue isolation, and the pathogenicity was verified by Koch's rule. The identification of pathogen was preliminarily determined by combining morphology. Furthermore, molecular biology identification was carried out based on the method of internal transcribed spacer and large subunit multi-locus gene joint construction. Phytopythium was isolated from Jian chuan County, Dali City, and Ning lang County, Lijiang City. It was confirmed through pathogenicity determination so that it could cause apple root rot. Through morphology combined with molecular biology characters. It was identified as Phytopythium litorale and P. cucurbitacearum. This study represents the first report of apple root rot caused by the pathogens P. litorale and P. cucurbitacearum in China. The results provide a theoretical basis for the development of monitoring disease occurrence and comprehensive control technology.

Broomcorn millet (Panicum miliaceum L.), one of the world's oldest cultivated crops, has excellent water use efficiency and is mainly used for dryland farming. In 2021, a new foliar disease of broomcorn millet occurred in Longdong of Gansu Province, China. The diseased leaves showed variably-sized, nearly circular brown blotches with dark brown margins, and the adaxial surfaces of blotches had small black dots. Based on morphological characteristics and multi-locus phylogenetic analysis involving ITS, LSU and RPB2, and the pathogenicity test, the pathogen of broomcorn millet causing leaf spot was identified as Boeremia exigua. To our knowledge, this is the first report of B. exigua causing leaf spot on broomcorn millet in China.

Prunus tomentosa is a deciduous shrub native to China that has been widely cultivated for an extended period throughout Eastern Asia for its flowers and fruit. Between 2021 and 2023, fruit anthracnose was observed in the Beijing and Shandong provinces of China. Symptoms initially presented as yellow, caviar-like patches on the fruit surface, which gradually enlarged into sunken brown spots, ultimately leading to fruit rot. To identify the causal agent, fungal isolate MYT24 as a representative strain was obtained from symptomatic fruits and identified as Colletotrichum fioriniae based on morphological characteristics and molecular phylogenetic analysis. The C. fioriniae was re-isolated from the disease fruit and the morphology was consistent with the original, fulfilling Koch’s postulates, which was confirmed as the causal agent of this disease. To our knowledge, this is the first report of C. fioriniae causing fruit anthracnose in P. tomentosa in China.

Hydrangea macrophylla, as one of the three major garden plants worldwide, has high ornamental and economic value. In March 2023, severe leaf spots were observed on H. macrophylla in the greenhouse in Xiqing District, Tianjin. Tissue separation was carried on to gain a pure strain that caused brown leaf spot on H. macrophylla, and its pathogenicity was confirmed based on Koch's postulates. According to morphological features and phylogenetic analyses of rDNA-ITS, GAPDH, and Alt a1 gene, the pathogen was identified as Alternaria alternata. This is the first report of A. alternata causing leaf spot on H. macrophylla in China, which is going to pave the road for disease diagnosis and effective control strategies.

Cigar is an important economic crop in Yunnan province. Recently, the wilt disease occurred seriously on cigar in Lincang city, Yunnan province, China. To explore the main pathogenic fungi of cigar wilt, pure strains were obtained from the disease samples by using the tissue isolation method. Twenty-one representative isolates were subsequently obtained and exhibited identical morphological characteristics. All isolates produced large conidia with sickle shap, small conidia with kidney shape, chlamydospores with round or oval shape; A representative isolate (YX39-1) was selected for molecular identification and the rDNA-ITS (GenBank accession No. ON918599), EF-1α (OR808022), β-tubulin (OP053690) and RPB2 (OP369287) gene sequences were 99.25%, 99.86%, 98.42% and 98.17% similar to those of Fusarium solani isolates (MT896771, ON843639, ON366357 and XM_046273849, respectively). Thus, the fungus represented by isolate YX39-1 was identified as F. solani based on cultural and morphological features. Pathogenic test showed that all inoculated plants exhibited symptoms similar to those observed in the field and YX39-1 was a strong pathogenic strain. The morphological and molecular identification of the fungal reisolated from inoculated plants confirmed its identity as F. solani, fulfilling Koch’s postulates. This is the first report of cigar wilt disease caused by F. solani causing in Lincang, Yunnan Province, China, which provides important information on the pathogen for disease management.

Maize yellow mosaic virus (MaYMV) as a newly identified Polerovirus causes leaf reddening in maize and yellow dwarf in wheat, leading to severe economic loss. In this study, the CP gene was amplified by RT-PCR from MaYMV-infected maize leaves, cloned into a prokaryotic expression vector pET28a (+) and transformed into the Escherichia coli strain BL21. The recombinant CP protein was expressed after induction with IPTG and used to prepare the antiserum by injection into New Zealand white rabbits. In-ELISA results showed that the titer of the antiserum was 1.024 × 10⁶. Dot-ELISA and Western blot analysis confirmed that the sensitivity of the antiserum to the MaYMV leaf sap was 1: 500, and the antiserum reacted specifically with MaYMV CP. These results indicate that the antiserum of MaYMV CP could be used for rapid detection of MaYMV. This study will provide an important basis for the monitoring and prediction of MaYMV.

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.