To clarify the pathogen species and isolation frequency inside and outside of soybean seeds in Inner Mongolia, and to make clear whether soybean seeds carry quarantine pathogen Phytophthora sojae, a total of 218 isolates were obtained from the inside of seeds and 196 isolates were obtained from the outside of seeds using washing assay and medial culture method, respectively. P. sojae was not isolated from the soybean seeds tested. Combined with colony morphology observation and ITS-rDNA sequence analysis, the above isolates were preliminarily identified. The internal isolates of seeds belonged to 16 genera, and the external isolates of seeds belonged to 17 genera. In combination with literature reports, 24 candidate fungal strains belonging to 9 genera were selected and tested for virulence, it showed that they all could cause lesions on etiolated soybean seedlings. Finally, the tested soybean seeds were confirmed to be free of P. sojae by specific primer amplification. These results provide an important reference for the scientific control of soybean diseases caused by seed borne pathogens.

In order to clarify the the population structure types, pathogenicity and the potential risks to different crops of Verticillium wilt of watermelon, the physiological type, physiological races, mating types and pathogenicity differentiation of Verticillium dahliae from watermelon were measured and the pathogenicity of 20 strains was studied by using root-drenching method. At the same time, the pathogenicity to watermelon of V. dahliae from six crops and the pathogenicity to four crops of V. dahliae from watermelon were determined. The results showed that all the 20 strains were identified as nondefoliated stains, physiological race 2 and MAT1-2-1 mating type. There were significant differences in the pathogenicity among the tested strains, the AUDPC values were from 238.92 to 606.81, the AUDPC values of WM05 and WM14 strains were 606.81 and 514.72, respectively, which were significantly higher than those of the other 18 strains. The pathogenicity of WM05 and WM14 strains was relatively strong. However, the AUDPC values of WM01, WM20, WM24 and WM19 strains were only 238.92, 249.15, 256.11 and 257.45, which showed relatively weak pathogenicity. V. dahliae from cotton, eggplant, potato, sunflower, tomato and honeysuckle could infect watermelon, and there were significant differences in pathogenicity. V. dahliae from watermelon could infect cotton, eggplant, potato and sunflower. The pathogenicity was the strongest on eggplant and was the weakest on cotton, and was comparable to that of watermelon on potato and sunflower.

Viruses in the genus Polerovirus of the family Solemoviridae exhibit a broad host range and can infect plants from many families, including Fabaceae, Solanaceae, Cucurbitaceae, Brassicaceae and others. They are responsible for significant economic losses globally and frequently co-infect with umbraviruses, which are members of the family Tombusviridae, leading to severe plant diseases. In order to explore the occurrence and distribution of poleroviruses in Yunnan, along with the potential outbreak risk associated with co-infection involving umbraviruses, a comprehensive disease survey was conducted in commercial crops including vegetables and fruits, as well as in the weeds surrounding these crops in Yunnan. Additionally, virus species were also detected and identified by RT-PCR. A total of 669 samples of 5 families, comprising 25 species of commercial crops and surrounding weeds, including vegetables, tobacco, potatoes, passion fruit and others, were collected from 7 states and cities in Yunnan Province, including Kunming, Yuxi, Baoshan, Dali, Chuxiong, Xishuangbanna and Honghe. Among the 11 commercial crops, 6 species of poleroviruses were found, which were the species potato leafroll virus, the species cucurbit aphid-borne yellows virus, the species suakwa aphid-borne yellows virus, the species pepper vein yellows virus 1, the species pepper vein yellows virus 3, and the species brassica yellows virus, respectively. Among them, PeVYV-3 had the highest average detection rate of 6.73% and was the dominant virus species in vegetables and fruits in Yunnan province. It was the first report in domestic and abroad that BrYV infected pea, PeVYV-3 infected eggplant, PeVYV-1 infected pea and broad bean, CABYV infected tobacco and pea. Moreover, the occurrence of SABYV in Yunnan Province was first reported. The host range of poleroviruses is gradually expanding, especially in various parts of Yunnan, indicating that the harm of poleroviruses to crops is gradually increasing. In addition, there is a risk of disease outbreaks with umbravirus co-infection. The research results contribute to a deeper understanding of the main types, distribution, and occurrence trends of poleroviruses in Yunnan, providing reference for comprehensive prevention and control of plant diseases caused by poleroviruses and their combined infection with umbraviruses.

To study the species and genetic variation of yam viruses in Henan province, 188 yam samples suspected of viral diseases were analyzed by high-throughput sequencing and RT-PCR. The results showed that five viruses were detected from yam samples: Japanese yam mosaic virus (JYMV), youcai mosaic virus (YoMV), yam latent virus (YLV), broad bean wilt virus 2 (BBWV 2) and yam yellow spot mosaic virus (YYSMV). The detection rates of JYMV, YoMV, YYSMV, BBWV 2 and YLV were 94.15 %, 87.23 %, 68.09 %, 42.02% and 29.79 %, respectively. 98.94% of the yam samples had complex infection. In this study, there were 20 complex infection types in 188 samples, among which JYMV + YYSMV + YoMV was the main complex infection type, and the detection rate was 26.60 %. Molecular variation analysis showed that YoMV and JYMV were more highly conserved, followed by YYSMV, YLV and BBWV 2, which showed more variation. Phylogenetic tree analyses indicated that the isolates obtained in this study were closely related to those from the same region. At the same time, HTS analysis results showed that other unclassified virus species were detected on yam, so it is necessary to conduct a comprehensive and systematic study on the types of yam viruses in Henan Province.

In order to investigate the occurrence and population genetic structure of tobacco vein banding mosaic virus on tobacco in Xingyi City, Guizhou Qianxinan Prefecture, and understand the genetic variation mechanism of tobacco vein banding mosaic viruses on tobacco isolates in Guizhou, Detection and identification of tobacco samples with typical TVBMV symptoms collected from Xingyi City, Qianxinan Prefecture, Guizhou Province were performed using electron microscopy negative staining, ultra-thin section preparation observation and molecular biology methods. Phylogenetic analysis and population genetic structure analysis of Guizhou tobacco samples was based on CP gene sequence of virus isolates using bioinformatics software. The results showed that among the 22 tobacco samples collected, the detection rate of TVBMV was 13.64%. The consistencies of nucleotide and amino acid sequences between the obtained TVBMV Guizhou tobacco isolate and the other 42 isolates published in GenBank were 94.1%-99.6% and 93.4%-100%, respectively. Phylogenetic analysis based on the amino acid sequence of the CP gene divides the isolates into four groups corresponding to the geographical distribution. The clustering results have obvious geographical distribution characteristics. Genetic diversity analysis shows that each group of TVBMV isolates exhibits a high level of genetic diversity due to the influence of geographical distribution. The analysis of population genetic structure shows that negative selection, genetic drift and ecological environment are the important effoectors for the genetic variation of TVBMV population. The research results provide theoretical support for the prevention and control of tobacco virus diseases and disease resistance breeding in Guizhou.

To clarify the types of viruses infecting Siraitia grosvenorii (Luo han guo) in Guangxi and provide instruction for the prevention, small RNA sequencing technology was employed to identify viruses, followed by PCR analysis to verify the results with degenerate and specific primer pairs. Then, the primers of corresponding viruses were used to investigate the distribution of virus species in the main production areas of S. grosvenorii in Guangxi. For these new viruses discovered in S. grosvenorii,all nucleotide sequences were characterized and phylogenetic trees were reconstructed, based on their amplified whole genomes. The results were as follows: according to small RNA sequencing and validation of polymerase chain reaction (PCR), leaves of S. grosvenoriifrom Guangxi University were infected with both squash leaf curl China virus (SLCCNV) and ageratum yellow vein China virus (AYVV) in Begomovirus, and both zucchini yellow mosaic virus (ZYMV) and papaya ringspot virus (PRSV) in Potyvirus. Further investigation revealed that all samples from Yongfu County, Lingui District and Longsheng County in Guilin and Qingxiu District in Nanning were infected with SLCCNV and ZYMV, and samples from Lingui District and Longsheng County in Guilin were also infected with PRSV. Their full-length genomes were all cloned,for SLCCNV-DNA-A (2 736 bp) and its four defective molecules, DNA-B (2 648 bp) and its two defective molecules, and AYVV (2 745 bp), which encode seven, two, and seven proteins, respectively. Sequence alignment and phylogenetic analysis indicated that the sequence of SLCCNV-DNA-A exhibited the closest identity tothat of the isolate from Yunnan, China, with 99.56% identity; the sequence of SLCCNV-DNA-B exhibited the closest identity tothat of the isolate from Thailand, with 91.41% identity, whose defective molecules exhibited recombination with exogenous genes; and the sequence of AYVV exhibited the closest similarity to that of a common weed isolate in Guangxi, with 97.83% identity.These indicated that S. grosvenorii was a new host for viruses in Begomovirus, and S. grosvenorii in Guangxi was co-infected with several virusesof both Begomovirus and Potyvirus.

Rice blast fungus has diverse polymorphism in paddy fields. To clarify the role of genetic recombination on biodiversity of Magnaporthe oryzae population in paddy fields, 336 single-spore isolates of M. oryzae were collected from five main rice-producing regions of Liaoning Province, and their difference on mating type distribution and fertility capacity were analyzed. The PCR amplification on mating type genes showed that all 336 isolates belonged to the same mating type, MAT1-2. The confrontation cultivations of all isolates with a standard strain P9 having an opposite mating type (MAT1-1) showed that the average proportion of fertile strains was 37.5% and the average number of perithecia of each cross was 38.8. Moreover, the fertility capacities of the isolates from the five main rice-producing regions were significantly varied. Taken together, these findings suggest that sexual reproduction of M. oryzae population in Liaoning Province is rare or probably non-existent though they retain certain fertility capacities, and the biodiversity of M. oryzae population in paddy fields may be attributed by other factors.

In this study, the mating types, physiological race composition, and genetic structures of 66 Phytophthora capsici isolates, collected from Chongqing during 2019-2020, were revealed by antagonistic culture, root-irrigation inoculation of differential hosts, and simple sequence repeats (SSR) marker-based analysis. The results showed that there were 53 P. capsici isolates of A2 mating type and 13 isolates of A1 mating type; 11 isolates of race 1, 28 isolates of race 2, 1 isolate of race 3, and 2 isolates of race 6. Genetic variation analysis of the P. capsici population, which consists of 11 different geographical sub-populations, was carried out by using six common SSR markers, and 59 different genotypes were obtained in total, with effective alleles of 1.786-2.881, expected heterozygosity of 0.352-0.577, Shannon-Wiener index of 1.242-2.079, and percentage for polymorphic markers of 83.33%-100%, and high levels of gene exchange occurring within subgroups (Nm=0.133-7.680) were indicated by medium population differentiation (F_ST=0.113). It was concluded that the degree of genetic variation of P. capsici populations in different regions of Chongqing was different, while the whole population had a surplus of heterozygotes, indicating a rich genetic diversity. The mating type proportion, fixation index, Hardy-Weinberg balance and linkage disequilibrium analysis for each geographical population showed that asexual and sexual reproduction may co-exist in P. capsici populations of Chongqing. Analysis of molecular variance (AMOVA) further showed that genetic variation mainly occurred within populations. Discriminant analysis of principal components (DAPC) showed that there were obvious differences and group division among P. capsici isolates from Chongqing, which could be divided into two groups. Structural analysis showed that P. capsici in Chongqing may come from two different ancestral groups. The results lay a basis for the control of Phytophthora blight of pepper plants.

The basal stem rot disease of belladonna (Atropa belladonna) occurred severely in the experimental farm of Shijiazhuang Academy of Agriculture and Forestry Sciences in May 2022. In order to effectively control the disease, identification, biological characteristics of the pathogen as well as disease control were carried out. The pathogen isolates causing belladonna basal stem rot disease was identified as Pythium aphanidermatum based on the morphological characteristics, rDNA-ITS sequence analysis and Koch's postulates testing. To our knowledge, the new disease is the first report in China. The optimum temperatures of mycelium growth, sporangium production and oospore formation were 35 ℃, 25-35 ℃ and 35 ℃, the optimum pH values were 7.0-9.0, 7.0-8.0 and 10.0, respectively. In addition, the optimum light condition and growth medium for culturing P. aphanidermatum were determined. The most suitable carbon sources of mycelium growth and sporangium production were soluble starch and glucose, and the most suitable nitrogen sources were ammonium nitrate and urea. Toxicity of nine chemical fungicides and one biological fungicide on mycelium growth of P. aphanidermatum were evaluated in the laboratory condition. The results showed that 35% metalaxyl-M FS, 250 g·L^-1 azoxystrobin SC, 98% hymexazol SP and 100 g·L^-1cyazofamid SC had strong inhibition abilities against the pathogen with EC₅₀ of 1.619, 2.069, 37.463 and 49.484 μg·mL^-1, respectively. All the work mentioned above provided a basic knowledge for rational control of belladonna basal stem rot.

From 2021 to 2022, jasmine plants with virus-like symptoms of mosaic, yellowing, chlorosis, ringspot and mosaic were observed in Yuanjiang county, Yuxi city and Chenggong district, Kunming city in Yunnan Province, and a total of 95 symptomatic jasmine samples were collected. RT-PCR detection was performed using the virus universal primers of genera Begomovirus, Luteovirus, Polerovirus, Potexvirus, Potyvirus, Tobamovirus and Umbravirus, and the specific primers of cucumber mosaic virus (CMV), jasmine mosaic-associated virus (JMaV), jasmine virus C (JaVC), jasmine virus H (JaVH), jasmine virus T (JaVT) and tobacco streak virus (TSV) for the diseased jasmine samples. The results showed that the diseased jasmine samples collected in Yuanjiang county of Yuxi city and Chenggong district of Kunming city were infected with JaVT, JaVH, JMaV, JaVC and CMV with the detection rates of 60.00%, 57.89%, 15.79%, 13.68% and 6.32%, respectively. JaVT and JaVH were the dominant viruses infecting jasmine in Yunnan. All the five viruses occurred in Yuanjiang and Chenggong, and the dominant viruses in these two regions were JaVH and JaVT. Meanwhile, the virus detection rate in Chenggong was lower than that in Yuanjiang. Viruses mostly cause damage to jasmine in the form of mixed infection, with 11 types of co-infection in the 5 jasmine viruses. JaVC and CMV are usually co-infected with viruses such as JaVH and JaVT. The co-infection of JaVH+JaVT had the highest detection rate at 26.31%. This study was the first to detect CMV infection in jasmine. To gain deeper insights into the molecular variation and phylogenetic relationship between the CMV jasmine isolate (CMV-YYJMLH) obtained from Yunnan Pro-vince and other CMV isolates found in different regions and host plants, the cp gene sequence of CMV-YYJMLH isolate (GenBank accession number: OQ870529) was compared and analyzed with those of 35 other CMV isolates documented in the GenBank. The results showed that isolate YYJMLH shared 77.17%-99.09% nucleotide (nt) sequence identity with other CMV isolates, among them, isolate YYJMLH had the highest nt sequence identity of 99.09% with the CMV pepper isolate (GenBank accession number: MT786689) from Yunnan province. A phylogenetic tree was constructed using the cp gene sequences of different CMV isolates, and results showed that the CMV-YYJMLH jasmine isolate belonged to CMV subgroup I, and the YYJMLH isolate had the closest genetic relationship with the CMV pepper isolate (GenBank accession number: MTT86689). To our knowledge, this is the first report of CMV naturally infecting jasmine worldwide and the first record of JaVT in Yunnan province.

In 2022, a study investigating viral diseases in three watermelon planting plots was conducted in Jiyuan, revealing an average incidence rate of approximately 97%. Twenty samples, comprising 14 watermelon samples, 4 melon samples, 1 pumpkin sample and 1 pigweed (Amaranthaceae retroflexus L.), were collected from the field. Three watermelon samples and one Amaranthaceae weed sample underwent small RNA sequencing, separately, and virus detect identified seven viruses from the four small RNA sequencing data sets. Subsequently, RT-PCR using primer pairs specific for 16 watermelon-infecting viruses identified the same seven viruses in all 20 samples. Watermelon mosaic virus (WMV) and zucchini yellow mosaic virus (ZYMV) had detection rates of 100% and 85%, respectively, making them the two most prevalent viruses in watermelon fields. WMV was also identified in pigweed, which could serve as an intermediate host of WMV in the field. The full genome sequences of four WMV isolates were derived from four data sets of small RNA sequencing. Comparing the identity and conducting a phylogenetic analysis based on the full genome sequences of WMV revealed that WMV isolates from Jiyuan have very high genetic diversity, suggesting that there could be multiple initial infection sources of WMV in the region. This study identified the causal agents of viral diseases in watermelon in Jiyuan; established a theoretical foundation for developing prevention and control strategies and conducting epidemiological research on viral diseases in watermelon in the region.

In order to investigate the RNA quality and virus content of CymMV and ORSV in different parts of Phalaenopsis aphrodite, plants infected with two viruses were used as experimental materials, a duplex TaqMan fluorescence quantitative PCR method was used to detect 7 sites of P. aphrodite: gynostemium, labellum, sepal, peduncle, leaf, aerial root and subterranean root. And the gene chip was used as a comparison method. The results showed that the RNA extraction effect of different parts was different. The RNA concentration of gynostemium was the highest, followed by labellum and aerial, and the lowest concentration was subterranean root. The results of duplex TaqMan fluorescence quantitative PCR showed that the CymMV and ORSV contents were the highest in the labellum and aerial root, and the lowest in the gynostemium and peduncle. The levels of both viruses also showed the same trend. This study provides some theoretical guidance for the selection of explants of P.aphrodite devirus seedlings and the selection of sites for virus monitoring samples.

To investigate the incidence and population genetic diversity of tomato zonate spot virus (TZSV) on tobacco in Yunnan, 560 samples of tobacco plants exhibiting symptoms of spot wilt were collected from various tobacco regions in this province. A pair of specific primers from the nucleocapsid protein (NP) gene were used to screen the samples. NP gene of the selected TZSV-positive samples was cloned, sequenced, and employed for phylogenetic, analyses, assessment of genetic diversity and determination of population differentiation. The results of RT-PCR showed that 262 out of the 560 samples were found to be infected with TZSV, with a mean positive detection rate of 46.8%. A significant recombination signal within the genome of the DX_LJHP_65 isolate was identified through recombination analysis. Phylogenetic analysis showed that 129 TZSV isolates can be divided into 6 groups, which tended to cluster according to their geographical origin, suggesting that the evolution of TZSV exhibits a pronounced geographical specificity. The mismatch distribution analysis results for the TZSV population in Yunnan indicated a multimodal distribution, suggesting that it has not undergone recent demographic expansion. The analysis of genetic differentiation among populations revealed a significant difference in gene exchange patterns. Specifically, the frequency of gene flow between the DX and DDB populations and other populations is found to be very low. On the other hand, there was frequent gene exchange observed between the remaining populations. This study is the first report on the genetic variation of TZSV isolate populations in various tobacco regions of Yunnan. It offers crucial insights that serve as a valuable reference for the prevention and control of TZSV.

Asarum plants showing leaf blight symptoms were collected from Xinbin County, Fushun City, Liaoning Province, China. To investigate the causal agent of the disease, pathogenicity test was carried out with XXY-2, a representative fungal strain that were isolated from the diseased plant tissues, and the result showed that it is the pathogen causing asarum leaf blight. Based on morphological characters, strain XXY-2 was identified as Talaromyces brevis. According to the results of multigene-combined (rDNA-ITS+BenA+RPB2) phylogenetic analysis, strain XXY-2 was grouped into the same branch of T. brevis model strains DTO 307^T and CBS 141833^T, further confirming that it belongs to T. brevis. Indoor toxicity tests of 8 fungicides against strain XXY-2 showed that pyraclostrobin and fludioxonil had a better inhibitory effect on mycelial growth of the strain, with EC₅₀ values of 0.0096 and 0.0056 μg·mL^-1, respectively. This is the first report of T. brevis as a pathogen of asarum leaf blight, making a theoretical basis for integrated control of the disease.

Peach latent mosaic viroid (PLMVd) is an important viroid infecting peach trees. PLMVd can cause various leaf symptoms including mosaic, yellowish and calico, etc. At present, the mechanism of PLMVd infection causing mosaic leaves is unknown. In this study, 86 full-length PLMVd sequences, in size of 336-338 nt, were isolated and cloned from the mosaic (M) and asymptomatic (N) leaves of nectarine trees collected in the field in China. By DnaSP 5.0 analysis, 31 haplotype (variant) sequences were obtained in the cloned sequences. The haplotype diversity (Hd) was relatively low as 0.79 for M isolates, while was high as 0.90 for N isolates. Compared with N isolates, sequence analysis showed that the sequence variation of M isolates mainly occurred in five regions of the whole sequence. MY1 haplotype sequence was dominant among those of M isolates, which clustered in phylogenetic group I with a few other variants and shared 89.4% identity with that of P1.148, a typical peach calico isolate. Through a comparative study of PLMVd cDNA infectious clones, gene synthesis and inoculation methods, the infectious PLMVd diploid cDNA clone construction and effective inoculation methods were established. The constructed MY1 diploid cDNA recombinant plasmid can infect the Prunus davidiana Franch systematically and exhibit typical mosaic symptoms after high-stressed stems slashing inoculation. The results will build a foundation for further study about the molecular mechanism of PLMVd inducing peach mosaic symptom.

Watermelon planted in early spring is a characteristic fruit in hot area of Yunnan Province. Its viral diseases are more and more serious in recent years. To detect and identify the main viruses, the plants and fruits samples of watermelon were collected from Menghai county, Xishuangbanna state, and transmission electron microscope (TEM) observation, indirect enzyme-linked immunosorbent assay (ID-ELISA), RT-PCR amplification and analysis of viral genome sequences were carried out. The results showed that the viruses infecting watermelon were watermelon silver mottle virus (WSMoV) and cucumber mosaic virus (CMV). The detection rates of WSMoV and CMV using ID-ELISA were 70% and 20%, respectively, in leaf samples, and of complex infection was 15%. The detection rates of these two viruses by RT-PCR were 100% and 65%, respectively, and of complex infection was 65%. However, the complex infection rate of these two viruses detected by RT-PCR amplification could reach up to 100% in seeds. Phylogenetic analysis demonstrated that the genome sequences of WSMoV [21YV-40(GenBank accession no.:OP617563), 21YV-43(GenBank accession no.:OP867047)] isolated in this study were similar to the squence of WSMoV [Banna-2011 (GenBank accession no.:KM242056)] isolated from Yunnan watermelon in 2016, and the similarity was 99%. The genome sequences of CMV [CMVYN40(GenBank accession no.:OP617565), CMVYN46 (GenBank accession no.:OP617566)] isolated in this study were similar to the sequence of CMV [A27(GenBank accession no.:FN552545)] isolated from watermelon in Thailand, and the similarity was 98%. This study demonstrated that the early spring watermelon was mainly infected by WSMoV and CMV, and complex infection was also common. The complex infection of WSMoV and CMV to both the plant and the seed of watermelon was reported for the first time. This study supplied a basis for virus prevention in the early spring watermelon.

To understand the occurrence and genetic evolution of sweet potato chorotic fleck virus (SPCFV) in Shandong province, China, 131 sweet potato samples were collected for the detection of SPCFV in 2019 and 2020, and two complete sets of genome sequences were amplified and analyzed. The SPCFV detection rate in 2019 and 2020 was 7.1% and 5.6%, respectively. All positive samples were co-infected with SPCFV and other sweet potato viruses. The two complete sets of genome sequences (CFV-SD1, CFV-SD2) were obtained by RACE and RT-PCR, with a total length of 9 105 bp and a nucleotide similarity with the reported isolates was 72.9% to 89.5%. Phylogenetic analysis of genome sequences revealed that all SPCFV isolates clustered into two groups based on the CP genes of six Shandong isolates and that all Shandong isolates belong to the Asian group (Asian isolates 1). Amino acid preference analysis showed that the first 35 amino acids in the N-terminal region of the SPCFV CP protein exhibited variation. This study indicated that Shandong province has become a frequent occurrence area of SPCFV and the virus population was diverse. The results provide a theoretical basis for the effective prevention and control of SPCFV.

Eight populations of Ditylenchus destructor were isolated from three tuber crops (Solanum tuberosum, Dioscorea esculenta and Dioscorea polystachya) in Shanxi Province. Morphology characteristics of D. destructor populations were observed and measured, and then the morphological data were analyzed by SPSS and PCA software. Nematode universal primers were used for PCR amplification and sequencing of rDNA-ITS. Similarity distance and sequence alignment were analyzed by Geneious Prime 2019.2.3 and DNAMAN 9.0 software, respectively. Analysis of variance of molecular variance (AMOVA) was constructed by Arlequin 3.5 software. The phylogenetic tree and haplotype network diagram were constructed by MrBayes 3.2.7 and PopART 4.8.4 software, respectively. The results showed that seven populations of D. destructor (YH277, YH279, tg38, XF01, CZ15, TY15 and tg49) are belong to type A, and their hosts are D. esculenta, S. tuberosum, and D. polystachya. Nevertheless, the PX04 population is belongs to type C and the host is S. tuberosum. The morphology of PX04 population is significantly different from the other seven populations, with the PX04 population having a slightly pointed tail. PCA analysis result also suggested that PX04 population was obviously separated from the other seven populations. The result of haplotype network structure was constructed using 77 ITS sequences of D. destructor isolated from D. esculenta, D. polystachya and S. tuberosum. The results showed that two shared haplotypes and 26 unique haplotypes. Among them, the frequency of the H1 was the highest among the three tuber crops, which suggests that it might be an ancestral haplotype; Among 26 unique haplotypes, the highest number of exclusive haplotypes and the most abundant haplotype and nucleotide diversities were found in the population of D. destructor parasitized the S. tuberosum, with a haplotype diversity index (Hd) of 0.841 and the inter-population nucleotide diversity index (Pi) of 0.005 02. The result of AMOVA analysis showed that the genetic differences of the D. destructor in Shanxi Province were mainly from inter-populations, and there was a sizeable genetic differentiation between type A and C of D. destructor.