First report of Athelia rolfsii (=Sclerotium rolfsii) associated with foot rot disease of Chrysanthemum morifolium in India

Chrysanthemum morifolium L. is an important flower crop grown in different parts of Karnataka for its striking cut flowers and international market value. During a field survey (Mysore district, Karnataka, February, 2022), chrysanthemum fields were found infected with foot rot disease. The presence of white mycelial structures with sclerotia were recorded near the stem-soil interface. The disease incidence ranged 10-12% measured in an area of approximately 10 hectares. The infected plants showed quick wilt, yellowing and toppling of the entire plant. Infected plants from Doddamaragowdanahally and Rayanahally (n=15) were collected and associated fungal pathogen isolated after surface sterilization with NaOCl (1%) on potato dextrose agar (PDA) amended with chloramphenicol (50 mg/L). Fungal mycelia developed from the infected tissues were inoculated on to fresh PDA plates to obtained pure cultures for further identification. Fungal colonies with dense, aerial whitish-cottony mycelia with uniformly globoid sclerotia (0.284.2 mm) were observed after 15 days of incubation (28 ± 2°C). Sclerotia were white in the beginning and turned brown at maturity. The average number of sclerotia produced per plate ranged from 240 to >480 (n = 10). To further to confirm the identity of the isolates, two representative isolates (CmSr1 and CmSr2) was subjected to molecular identification based on ITS-rDNA sequences. Briefly, genomic DNA was isolated from 12 day old cultures using the CTAB method and ITS-rDNA was amplified using ITS1-ITS4 primers (White et al., 1990). An expected amplicon of >650 bp (ITS) was obtained and later sequenced from both the directions. The consensus sequences were analysed through nBLAST search which revealed that 100% sequence similarity with reference sequences of Athelia rolfsii (S. rolfsii) from GenBank database (MT127465, MN974137, KC292637; identity 656/656; 0 gaps). A phylogenetic tree obtained by the neighbor-joining method using MEGAX shared a common clade with the reference sequences retrieved and computed, thus confirming the identification based on sequence analysis and molecular phylogeny. The representative sequence of A. rolfsii isolates CmSr1 and CmSr2 isolates deposited in GenBank with Accession nos. ON456153 and ON456154, respectively. Based on etiology, morphological, cultural and molecular data the pathogen was identified as Athelia rolfsii (Curzi) Tu & Kimbrough (Syn: Sclerotium rolfsii Sacc.) (Mordue, 1974; Mahadevakumar et al., 2016, 2018). Plants (n=60) were inoculated with sclerotial bodies (2 sclerotia/plant) near stem soil interface under green house and covered with polythene bags (at 27 ± 2°C and 80% RH). Non-inoculated plants (n=20) served as controls. The development of foot rot disease was observed eight days after inoculation. A total of 48 plants showed the foot rot symptoms and 12 inoculated plants and control plants remained healthy. The identity of the fungus was confirmed by morphological and cultural characters after re-isolation. C. morifolium is an important flower crop in Karnataka. S. rolfsii is known to be associated with blight and collar rot of Chrysanthemum spp. from Kerala (Beena et al., 2002) but no species (host) identity provided. Therefore, to the best of our knowledge, this is the first report of foot rot disease caused by Athelia rolfsii on C. morifolium in India. Early diagnosis of this disease will help the farmers to adopt suitable management practices to avoid loss.

First Report of Fusarium oxysporum Causing Stem Rot on Mammillaria humboldtii in China

Mammillaria humboldtii found in Mexico is a short-globose ornamental cactus species of the Cactaceae family, which has gained increasing popularity in China. It is characterized by tuberculate stems, dimorphic areoles, small pink flowers and pitted seed cell walls. The populations of wild M. humboldtii are critically endangered and are now of international conservation concern. In July 2021, stem rot symptoms were observed on M. humboldtii in a commercial greenhouse located in Zhangzhou (117°39'44.0064″E, 24°28'3.7236″N), Fujian Province (southern China). The typical symptoms were water-soaking, rotting and wilting on the stem, eventually leading to necrosis of the plants within 20 to 30 days. The vascular system of infected stems and roots showed a reddish-brown discolouration. The disease affected approximately 10% of 1000 plants. Fungi were isolated from the diseased stems of 26 samples, which were chopped into small pieces (5 × 5 mm), surface-sterilized with 75% ethanol for 40 s, and placed onto potato dextrose agar (PDA). After seven days of dark culture at 28°C, morphologically similar fungal isolates with whitish aerial mycelium and purple pigment were observed. On carnation leaf agar (CLA), isolates produced sickle and slightly curved macroconidia with three to four septa, measuring 12.8 to 27.9 × 1.9 to 3.8 μm (n = 15), and unicellular, ovoid to elliptical microconidia measuring 3.8 to 7.7 × 1.4 to 2.5 μm (n = 30). Smooth walled chlamydospores were terminal or intercalary, single or in pairs, measuring 9.2 to 13.1 μm (n = 15) in diameter. For molecular identification, the internal transcribed spacer (ITS) region of rDNA (Schoch et al. 2012), translation elongation factor-1α (EF1-α) (Maryani et al. 2019) and gene coding endopolygalacturonase 1 (PG1) (Hirano et al. 2006) of the representative isolate FJMH7 were amplified, purified and sequenced. BLASTn analysis of the ITS, EF1-α and pg1 sequences (GenBank accession numbers: ON832660, ON843495 and ON843496) showed 100%, 99.70% and 98.96% identity with F. oxysporum (GenBank accession numbers: KX611626, OM801797 and KF437345), respectively. Phylogenetic analysis based on the the concatenated ITS and EF1-α sequences and pg1 genes placed isolate FJMH7 with F. oxysporum reference strains in the phylogenetic trees. Based on morphological identification and sequence analysis, this isolate was identified as F. oxysporum. For the pathogenicity assay, six 6-month-old healthy plants of Mammillaria humboldtii were inoculated by dipping roots in a conidial suspension (106 conidia/mL) of isolate FJMH7 cultured in Bilai's medium for three days. Six noninoculated plants treated with Bilai's medium served as a control. Plants were transplanted into pots filled with sterilized soils and placed in a glasshouse at 25°C. After 15 days, all the inoculated plants exhibited rot symptoms on stems, which were similar to those observed in the commercial greenhouses. All inoculated plants were dead 30 days after inoculation. Control plants did not show any symptoms. F. oxysporum was reisolated and confirmed based on morphology and sequencing. No fungi were reisolated from control plants. To fulfil Koch's postulates, the pathogenicity assay was repeated twice with the same results. To date, F. oxysporum isolates have been reported on golden barrel cactus (Echinocactus grusonii) (Polizzi et al. 2004), night-blooming cereus (Hylocereus undatus) (Wright et al. 2007), apple cactus (Cereus peruvianus monstruosus) (Garibaldi et al. 2011), Schlumbergera truncate (Lops et al. 2013), Astrophytum ornatum (Quezada-Salinas et al. 2017) and Nopalea cochenillifera (Santiago et al. 2018). To our knowledge, this is the first report of F. oxysporum on M. humboldtii in China, indicating that this pathogen could cause wilt and rot disease on different cactus hosts.

First Report of Fusarium acuminatum Causing Dianthus chinensis root rot and foliage blight in China

Dianthus chinensis is a popular ornamental plant that is widely cultivated in China. In May 2020, a disease was found at several landscape sites in Xuanwu District, Nanjing, China, causing symptoms of foliage blight and root discoloration on approximately 52% of one-year old D. chinensis plants. To recover the causal pathogen, samples of infected roots and leaves were cut into 5×5 mm2 pieces, surface-disinfected in 75% ethanol for 30 sec, followed by 1% NaClO for 90 sec, rinsed with sterile water three times and placed on potato dextrose agar (PDA) with 0.1 mg/mL of ampicillin at 25 ⁰C. Hyphae growing on PDA were visible from both root and leaf tissues after three days. Individual hyphal tips were transferred to new PDA plates to obtain pure isolates. Three representative isolates were deposited in the China Forestry Culture Collection Center (CFCC 57545,57546, 57547). The hyphae grew radially, densely, and the aerial hyphae were velvety, white, yellow-white, or pink-white. Representative isolate Facu-DCY5 produced three types of conidia (microconidia, macroconidia, and chlamydospores). Macroconidia were sickle-shaped, measuring 25.7-55.4 µm × 3.2-4.6 µm (n=50). Microconidia were numerous, oval or kidney-shaped, measuring 6.8-11.9 µm × 3.5-4.8 µm (n=50). Conidia produced in the aerial mycelium were 16-34 × 2.2-5.3 µm (n=50). The ITS region, TEF1, calmodulin (CMDA), and RNA polymerase II second largest subunit (RPB2) were amplified with primers ITS1/ITS4, EF1/EF2, CL1/CL2A and 5F2/7CR , respectively and sequenced at Sangon Biotech (Nanjing, China). The ITS sequence of isolate Facu-DCY5 (GenBank No. ON307073.1) was identical to HQ165938.1, ON306850.1, OM964482.1. TEF1 (ON331997.1) was identical to LC546967.1, HQ165866.1, MZ158155.1. CMDA (ON331996.1) was identical to HQ412345.1, MZ921595.1 and MZ921597.1. RPB2 (ON331995.1) was identical to MZ997370.1. Maximum parsimony and maximum likelihood phylogenies of the Facu-DCY5 multilocus sequence data and those of several species within the F. tricinctum species complex identified the isolate from D. chinensis as F. acuminatum . Pathogenicity tests were performed using a conidial suspension (104 conidia/mL). Each plant (approx. 0.3 m in -height) was inoculated with 1 mL of the conidial suspension by mixing it into the potting soil (500 g). Control plants were treated with sterile distilled water. All inoculated plants (n=9) in three repeats of the assay exhibited foliage blight and root rot after 15 days, whereas all control plants (n=9) remained asymptomatic. Fusarium isolates with identical morphological features and molecular marker sequences to those of Facu-DCY5 were recovered from foliage blight and root tissues of all the inoculated plants. In China, F. acuminatum has been reported as a pathogen of Cucurbita maxima, Actinidia arguta, Polygonatum odoratumand Schisandra chinensis. This is the first report of F. acuminatum on D. chinensis in China. Considering the importance of D. chinensis to both ornamental nurseries and landscaping industries, we recommend that diseased plants be removed to prevent the spread of F. acuminatum, and that identification of the infecting isolates from D. chinensis at other sites and landscape locations be performed.

Occurrence of leaf rust disease in Oxalis triangularis caused by Puccinia oxalidis in Valdivia, Chile

False shamrock (Oxalis triangularis), native to South America, is an ornamental and popular plant bulb, commercialized for their attractive shape and color (purple triangular leaves) (Taha et al., 2013). In Chile, a rust was detected in O. triangularis plants growing from April to June in several gardens (n=10) in the city of Valdivia, estimating a disease incidence between 80 and 100%. The symptoms appeared as diffuse chlorotic spots from the upperside of leaves, where infected tissues eventually become completely necrotic, and yellow rust pustules were observed on the underside of leaves. Severe symptoms on infected leaves were consistently observed, showing necrosis on entire leaves. Symptomatic plants (n=50) were collected, and three representative isolates from different localities (OX1, OX2, and OX3) were used for morphological and genetic identification. Uredinia (n=20) were hypophyllous, erumpent, yellow, and irregularly distributed, with sizes from 340 to 850 μm in diameter. Urediniospores (n=150) were yellow, subglobose to globose, equinulate, with measures of 14.2 - 17.7 x 14.7 - 17.2 µm. Teliospores were absent. Based on morphological characters, this rust was identified as a Puccinia sp. These morphological characteristics coincided with those indicated by Šafránková (2014), Abbasi et al. (2018), and Khouader et al. (2018). To classify this rust genetically, sequences analyses were performed using the ITS region of the rDNA (ITS4/ITS5) (White et al., 1990). The DNA was extracted using a commercial kit. The results indicated 99% similarity with two reference sequences of P. oxalidis (MH325473 and MH325474) available at GenBank (NCBI http://www.ncbi.nlm.nih.gov/BLAST/). The sequences obtained were deposited in GenBank (ON259085 to ON259087). Based on the maximum parsimony phylogenetic tree, the sequences of Chilean isolates were clustered with those of P. oxalidis references. Pathogenicity tests were conducted using three isolates (OX1 to OX3). Surface disinfection of leaves of O. triangularis (n=36 plants), were performed by spraying 1% NaOCl solution for 1 min. Subsequently, 2 mL of urediniospores suspensions of each isolate (OX1 to OX3) at a concentration of 106 urediniospores/mL, were sprayed with an atomizer on the underside of the leaves of all plants. Urediniospores were obtained following the methodology proposed by Ferrada et al. (2020). Control leaves were disinfested and inoculated with sterile distilled water. Plants of O. triangularis of 90-day-old were incubated in a humid chamber (24°C, 80% HR), with a photoperiod of 12 light /12 dark. At 11 days post-inoculation, all leaves inoculated developed chlorosis spots and pulverulent pustules (averaged 10.9 to 25.4 pustules per leaf), and then at 26 days post-inoculation, affected leaves showed necrotic tissues. The identity of these isolates was confirmed morphologically. The symptoms in the control leaves were negative. To our knowledge, this is the first report of multiple occurrences of the leaf rust disease on gardens of false shamrock caused by P. oxalidis in Valdivia, south of Chile. Previously, P. oxalidis has been reported to cause leaf rust disease in O. triangularis in the Czech Republic (Šafránková, 2014) and O. debilis in Korea (Lee et al., 2018). The leaf rust disease could represent a threat to the ornamental gardens of O. triangularis in Valdivia. Currently, epidemiological studies of leaf rust disease are necessary to develop management strategies in gardens of O. triangularis.

Natural occurrence of broad bean wilt virus 2 on Mirabilis jalapa in China

Mirabilis jalapa Libosch. is an annual ornamental herbaceous plant. Its leaves and roots are used as a traditional folk medicine that function in clearing heat and detoxifying, promoting blood circulation, regulating menstruation, and nourishing kidney (Annapoorani et al. 2014; Liu et al. 2020; Wang et al. 2018). Broad bean wilt virus 2 (BBWV-2), which belongs to the family Secoviridae, is transmitted by aphid in a non-persistent manner in the nature (Kondo et al. 2005) and mainly damages Vicia faba, pepper, yam and spinach (He et al. 2021). The leaves of M. jalapa on the campus showed shrinking (Supplementary Fig. 1A), yellowing (Supplementary Fig. 1B), mosaic (Supplementary Fig. 1D & 1E), and the whole plant had stunted and rough (Supplementary Fig. 1A & 1C) symptoms in the autumn of 2021. Eight plants (S21-S28) with these symptoms were harvested for total RNA extraction, siRNA mixture purification, and siRNA library made (NEBNext® Ultra™ II RNA Library Prep Kit for Illumina®, NEB, UK). The high-throughput siRNA sequencing with pair-end method was performed on Illumina Hiseq 2000 platform (Sangon, Shanghai, China). The raw sequencing data was treated with the Illumina's CASAVA pipeline (version 1.8). The adaptor was removed and the reads were mostly distributed in 21-24 nt length area (Supplementary Fig. 2A). The contigs (∼12,500, Length > 350 bp) were obtained by de novo assembling with the Velvet Software 0.7.31 (k = 17), then the BLASTN was preformed against GenBank database. Surprisingly, 237 contigs showed significant nucleotide sequence similarities to the genome of BBWV-2. To determine the incidence of BBWV-2 to M. jalapa in campus garden, twenty-eight leaf samples were randomly collected from the garden. Leave extract and total RNA of the sample were tested for BBWV-2 by ELISA (Agdia, USA, SRA46202/0096) and RT-PCR assay, respectively. Twenty-two samples were infected compared with the positive control, and their readings of ELISA were above or parallel to the positive control (Supplementary Fig. 2B∼2D). The coding sequence (1,395 bp) of BBWV-2 movement protein (MP) was amplified by a specific pair of primers (Supplementary Table S1) according to the contigs, the results indicated that the 22 out of 28 samples (78.6%) tested positive for BBWV-2 by both ELISA and RT-PCR (Supplementary Fig. 2E). The MP fragment of BBWV-2 obtained from one of the sample was purified by TIANgel Midi Purification Kit (Tiangen, Beijing, China) and then cloned into pMD19-T (TaKaRa, Dalian, China) vector. Ten separate clones were selected and sequenced (Sangon, Shanghai, China) after PCR verification. The obtained sequences (GenBank accession No. OM416039) were analyzed by BLASTN and bioEdit software (version 7.2.3). According to the phylogenetic tree constructed by BBWV-2 MP sequences (Supplementary Fig. 3), the obtained MP sequences (OM416039, ON677747, and ON677748) were most related to the BBWV-2 MP sequences that from pepper (GenBank accession No. JX183228.1), they share the nucleotide identity of 84.87%. To determine the occurrence and distribution of BBWV-2 in other areas, another twenty-two samples were randomly collected for RT-PCR in different regions of Jiangsu Province, China (Supplementary Table S2). The BBWV-2 infection rate was 76.0% in the M. jalapa. In sum, this is the first report of BBWV-2 naturally infecting M. Jalapa in China.

First report of Phytophthora blight caused by Phytophthora nicotianae on Daphne odora in China

The variegated leaves and fragrant flowers of Daphne odora var. marginata Mak. make it a popular garden plant. In May 2020, we found diseased D. odora plants in a greenhouse at the Ganzhou Vegetable and Flower Research Institute, in southeast China; 72% of 1800 plants had Phytophthora blight-like symptoms-shrunken stems, black withered branches, wilted and dropped leaves (Fig 1a), and rotted and dark green roots. The root and stem tissue surfaces were disinfected with 75% ethanol for 30 s followed by 0.1% HgCl2 for 1 min, rinsed thrice with sterile water, and cultured on potato-dextrose agar (PDA) medium at 25°C. Mycelia from the diseased tissue were subcultured on fresh PDA medium, providing three colonies. White colonies (~4.1 mm) were formed after 10 days at 25°C (Fig 1b). Sporangia and chlamydospores were induced by placing actively growing mycelia on PDA medium at 25°C for ~30 days and then at 45°C for ~3 days. Sporangia were ovoid to spherical and 19.33 × 20.99 µm in size (Fig 1c), whereas chlamydospores were spherical and 15.68 × 16.10 µm in size (Fig 1d). All three colonies resembled Phytophthora spp. Genomic DNA was extracted from isolates using the Ezup Column Fungi Genomic DNA Purification Kit (Sangon Biotech [Shanghai] Co. Ltd.), and rDNA-ITS and β-tubulin were amplified and sequenced. BLAST analysis (GenBank) revealed that the ITS (Accession No. MZ676071) and β-tubulin (MZ748503) sequences of isolates shared the highest similarity (99-100%) with those of Phytophthora nicotianae (Duccio et al. 2015). A phylogenetic tree of the relationship between our isolate hjt3 and its close relatives within the P. nicotianae species was constructed using the MEGA X neighbor-joining method (Fig 2). The pathogen was identified as P. nicotianae based on morphological and molecular characteristics. Sequencing results of the three samples were consistent, all indicating P. nicotianae. A specimen (JXAU-H2020245) was deposited in the Herbarium of the College of Agronomy, Jiangxi Agricultural University. To confirm pathogenicity, 9-month-old healthy D. odora plants were used for stem and soil inoculation. Stems were cut ~5 cm from the soil with sterilized scalpels and inoculated with 0.8 cm diameter PDA plugs containing actively growing mycelia of isolate hjt3. The soil was sterilized and 0.8 cm PDA plugs containing actively growing mycelia were buried in the soil at ~5 cm; the mycelia were in contact with the roots. Plants in both groups were treated equally; those inoculated with sterile PDA plugs served as controls. There were six plants in each group, with each experiment performed in triplicate. All plants were incubated in a greenhouse at 25-28°C. The stems shrank and began to rot rapidly after 7 days (Fig 3) and the branches turned black and withered within 2 weeks. After soil inoculation, the stems of the inoculated plants blackened and rotted in ~20 days (Fig 4) and the roots rotted and turned dark green (Fig 5). These symptoms rapidly spread to the branches. The control plants did not exhibit any symptoms. Reisolated colonies showed the same morphological traits as the isolates used for inoculation; no target colonies were isolated from the control plants. Phytophthora blight caused by P. nicotianae on D. odora has been reported in Italy (Garibaldi A, 2009) and Korea (Kwon et al. 2005). This is the first detection in China. Therefore, Phytophthora blight on D. odora caused by P. nicotianae should be monitored and controlled to promote the development of the D. odora industry.

Confirmation of Burkholderia gladioli as the Causal Agent of Bacterial Scab on Gladiolus (Gladiolus spp.) in Ohio

Ohio is one of the top five floriculture producers in the United States, grossing over $200 million annually (NASS 2019). Within the international floriculture trade, gladiolus cut flowers represent the fifth highest grossing crop (Ahmed et al. 2002). In September 2021, the Ornamental Crops Pathology Lab at the Ohio State University received a gladiolus (Gladiolus spp.) sample of an unknown cultivar from a home garden in Franklin Co., OH where several plants had failed to grow from planted corms or were stunted and displaying symptoms of disease. Bleached, water-soaked spots with necrotic margins along the flowering stems, stunted flowers with partial necrosis, and necrotic bracts were observed on the submitted sample. Bacterial isolations were performed by surface disinfesting small sections of bract tissue from the border of a lesion by soaking in 10% bleach for 30 sec and rinsing twice in sterile water, macerating the tissue in sterile water, and streaking the suspension on nutrient agar (NA) plates. Plates were incubated at 28°C for 48 hours and the resulting colonies were purified by re-streaking a single colony on NA twice. Bacterial colony morphology on NA presented as cream-colored and shiny with an irregular form and undulate margin. Five in vitro tests were performed using one representative isolate to identify the bacterium to the genus level: (1) confirmed levan production, (2) confirmed pectinolytic activity, (3) confirmed ability to grow at 40°C, (4) inability to grow under anaerobic conditions, and (5) a negative oxidase test (Schaad et al. 2000). All test results identified the genus as Burkholderia. To identify to species level, gyrase subunit B (gyrB) and RNA polymerase subunit D (rpoD) markers were PCR amplified and sequenced using primers UP1-E/AprU, and 70F2/70R2, respectively (Maeda et al. 2006). NCBI GenBank BLASTn comparison showed that the gyrB sequence shared 99.33% identity to the type strain of B. gladioli (CP009323.1), while the rpoD sequence showed 99.53% identity (CP009322.1). Sequences were deposited in GenBank under accession numbers ON597852 (gyrB) and ON597853 (rpoD). To confirm pathogenicity, each of two Gladiolus communis 'Mini Elvira' potted plants were inoculated with two bacterial and two control treatments (3 leaves/treatment/plant) as follows: leaf infiltration with 1 mL of either (i) a distilled water-Tween 20 (0.03% v/v) bacterial suspension (106 cfu/mL) or (ii) a sterile water-Tween 20 suspension using a needle-less syringe; foliar spray with either (iii) the bacterial suspension or (iv) water-Tween suspension until run-off. Following inoculation, plants were covered for 24 hours with a plastic bag to increase humidity and favor infection and maintained in a greenhouse at an average temperature of 23°C. After 3 days, water-soaked, necrotic lesions were observed on the inoculated plants regardless of inoculation method, while control leaves remained asymptomatic. To fulfill Koch's postulates, bacteria were re-isolated from the lesions 7 days post-inoculation and confirmed to be identical to the original isolate based on rpoD gene sequencing. Bacterial scab of gladiolus was reported in Ohio in the late 1900s as caused by Pseudomonas gladioli (syn. P. marginata; Ellett, 1989). To the best of our knowledge, this report represents the first molecular identification of the causal agent as Burkholderia gladioli. In Ohio, the pathogen has also been observed causing slippery skin on onion but not officially reported in the peer-reviewed literature. Additionally, B. gladioli has been reported in other parts of the United States on orchid, corn, and rice (Keith et al. 2005; Lu et al. 2007; Nandakumar et al. 2009). Given the significant role of gladiolus within Ohio's floricultural trade, as well as the ability of this pathogen to infect other regional crops, monitoring of bacterial scab is important for floriculture and field crop growers alike.

First report of Phyllosticta capitalensis causing leaf spot of Mahonia fortunei in China

Mahonia fortunei, belonging to the Berberidaceae family, is widely cultivated in fields, parks, courtyards, and roadsides for its excellent ornamental characteristics and medicinal values in southern China (Yu and Chung 2017). In May 2021, leaf spots were observed on nearly 60~80% of M. fortunei plants growing in Chongqing Normal University campus (29°36'42″N; 106°17'59″E) from Chongqing City, China. The typical symptoms on leaves were irregular spots with gray centers, brown edges, and chlorotic halos, about 1 to 7 mm in diameter, and eventually coalesced forming larger necrotic areas. Twenty symptomatic leaves were randomly sampled from five diseased plants. Tissues were cut from the lesion margins and surface sterilized in 75% ethanol for 1 min, rinsed thrice with sterile water, dried on sterilized paper, plated on potato dextrose agar (PDA) plates, and incubated at 25°C for 7 days in the dark. A total of 20 isolates were obtained from the infected leaves. Pure colonies of all fungal isolates had similar characteristics, and three isolates were randomly selected (SD11, SD18, SD19) for further study. Colonies of this fungus were olivaceous greenish to olivaceous black with a granular surface, and irregular light olive edges, finally turning black on PDA. Pycnidia were black, globose, granular, and in clusters. Conidia (n=30) were hyaline, aseptate, unicellular, obovoid to ellipsoid, narrow end with single apical appendage, and 7.5~11.2 × 4.5 ~6.5 μm. The DNA of three isolates were extracted and the internal transcribed spacer (ITS) region, actin (ACT), and translation elongation factor 1-α (TEF1) genes were amplified and sequenced using the primers ITS1/ITS4 (White et al. 1990), ACT512F/ACT783R, and ER728F/EF986R (Carbone and Kohn 1999), respectively. The sequences of three isolates were 100% identical, and one representative isolate SD18 were deposited in GenBank (ON231754, ITS; ON246259, ACT; and ON246258, TEF1). Sequence analysis revealed that the consensus sequences of ITS, ACT, and TEF1 of isolate SD18 was 99 to 100% identical to each sequence of an Indonesian strain (CBS 117118) of P. capitalensis from Musa acuminate (FJ538339 for ITS, FJ538455 for ACT, FJ538397 for TEF1). Phylogenetic analysis using Maximum Likelihood and concatenated sequences (ITS+ACT+TEF1) with MEGA7 placed isolate SD18 in P. capitalensis with 100% bootstrap support. Based on these morphological and molecular characteristics, the isolates were identified as P. capitalensis (Wikee et al. 2013). To fulfill Koch's postulates, 8 healthy potted plants were inoculated with 106 conidia/ml suspension of isolate SD18 by spraying the leaves, and another 8 plants were sprayed with sterile distilled water as control. All plants were covered with plastic bags for two days and then arranged in a greenhouse with 80% relative humidity at 25°C. The pathogenicity test was repeated thrice. After 18 days inoculation, the similar symptoms were observed on the inoculated plants, whereas control plants remained healthy. The pathogen was reisolated from symptomatic tissue and identified as P. capitalensis by the methods described above. P. capitalensis has been reported causing leaf spot on various host plants around the world (Wikee et al. 2013), recently found on tea plant, castor, and oil palm (Cheng et al. 2019; Tang et al. 2020; Nasehi et al. 2020). This is the first report of P. capitalensis causing leaf spot on M. fortune in China, and will establish a foundation for controlling the disease.

First report of 'Candidatus Phytoplasma asteris' associated with witches'-broom disease of Cinnamomum camphora in China

Camphor tree (Cinnamomum camphora) has a wide distribution in the world and is mainly distributed in the South and southwest in China. It can be used as both a wood and a medicine, with high value in industry, medicine, and ecology. In May 2022, it was observed that the approximately ten to fifteen years old Camphor trees were exhibiting witches'-broom, small leaf morphology and chlorosis, and leaf drop in Panzhihua City, Sichuan Province, China. The witches'-broom symptoms consisted of many small branches with little leaves at the top of branches. It was named C. camphora witches'-broom disease (CCWB) and was found in some areas of Miyi, Yanbian, Renhe Xiqu and Dongqu counties. More than 28% of the plants were infected on the five areas surveyed. Total 100 samples were collected from five areas, with 15 symptomatic plants and 5 asymptomatic plants each area. The lateral stem tissues were observed under a scanning electron microscope (Hitachi S-3000N). The nearly spherical bodies were found in the phloem sieve cells of symptomatic plants. Total DNA extraction was conducted from 0.1 g tissue using the CTAB method (Porebski et al. 1997), ddH2O was used as the negative control, and Dodonaea viscose witches'-broom disease plants were used as the positive control. The nested PCR was employed to amplify the 16S rRNA gene (Lee et al. 1993; Schneider et al. 1993) and PCR amplicon of 1.2 kb were amplified (GenBank accessions OP662614; OP662615; OP662616). The direct PCR specific to the ribosomal protein (rp) gene yielded amplicons of approximately 1.2 kb with primer pair rp(I)F1A and rp(I)R1A (Lee et al. 2003) (GenBank accessions OP649592; OP649593; OP649594). The fragment from 25 symptomatic samples was consistent with the positive control, and asymptomatic plants were negative, confirming an association of a phytoplasma with the disease. A BLAST analysis of the 16S rRNA sequences of CCWB phytoplasma showed that it has a 99.44% similarity with Trema laevigata witches'-broom phytoplasma (GenBank accession MG755412). The rp sequence shared 99.59% identity with rapeseed phyllody phytoplasma (GenBank accession CP055264). An analysis with iPhyClassifier showed that the virtual RFLP pattern derived from the query 16S rDNA fragment of CCWB phytoplasma is most similar to the reference pattern of the 16Sr group I, subgroup B (OY-M, GenBank accession AP006628). The phytoplasma is identified as 'Ca. Phytoplasma asteris'-related strain belonging to sub-group 16SrI-B. The phylogenetic tree was constructed based on 16S rRNA gene and rp gene sequences by using MEGA version 6.0 (Tamura et al. 2013) with neighbor-joining (NJ) method and bootstrap support was estimated with 1000 replicates. The result indicated that the CCWB phytoplasma formed a subclade in 16SrI-B and rpI-B respectively. In addition, the plants were positive for the phytoplasma using nested PCR after grafting for 30 d in nursery conditions. It is noteworthy that the plants were seriously damaged by aphid, Psyllidae and Ceroplastes. It is speculated that the insects of Homoptera typically transmit phytoplasmas by feeding on plant sap, thus it is necessary to control aphids in order to control the C. camphora witches'-broom disease. To the best of our knowledge, Camphor tree is a new host plant of 'Ca. Phytoplasma asteris' in China. The newly emerged disease is a threat to Camphor tree production.

First report of meadow saffron breaking virus on wild Colchicum autumnale from a stricly protected Natura2000 site at a Hungarian National Park

In mid-April of 2018 light green to greenish yellow linear stripes (Fig. S1.) were observed on the foliage of meadow saffron (Colchicum autumnale) plants - which are native to Hungary - at a strictly protected Natura2000 site maintained by the Duna-Ipoly National Park (DNPI). By autumn, during the flowering season, flower breaking symptoms (Fig. S2.) were noticed, which indicated possible viral infection. With the permit of the Government Office of Pest County and the DNPI, 200 mg leaf sample was collected from one symptomatic plant in spring 2021 and stored at -70 °C until further processing. At the time of the sampling about 2.5 % of the ~ 5000 meadow saffron were symptomatic. Multiplex RT-PCR testing of the sample and an asymptomatic C. autumnale plant for cucumber mosaic virus, tomato spotted wilt virus (Nemes and Salánki 2020) and Nepovirus subgroup-A (Digiaro et al. 2007) gave negative results. The asymptomatic plant also tested negative for potyviruses (Salamon and Palkovics 2005). The asymptomatic (healthy) C. autumnale plant was inoculated with leaf sap of the sample (0.02M Sörensen's phosphate buffer pH 7.2 + 2 % PVP-40 (m/v)) resulting in symptoms of flower breaking in autumn of 2021, and linear stripes on the foliage in spring 2022, identical to symptoms on the originally infected plant. ELISA tests were carried out on the source plants in duplicate using potyvirus-specific MAb PTY1 antibodies (Jordan and Hammond 1991) (Agdia, Elkhart, IN, USA). Absorbance values were 1.519 and 1.530, while the negative controls were 0.003 and 0.007, respectively indicating potyvirus infection of the sample. Molecular tests were carried out on the source and inoculated plant samples in 2022. Total nucleic acid was extracted with the modified CTAB protocol of Xu et al. (2004), and reverse transcription was carried out with Maxima H Minus First Strand cDNA Synthesis Kit (Thermo Fisher Scientific Baltics UAB, Vilnius, Lithuania) with poly T2 (5'-CGGGGATCCTCGAGAAGCTTTTTTTTTTTTTTTTT-3') primer (Salamon and Palkovics 2005). PCR amplification was carried out with poty7941 (5'-GGAATTCCCGCGGNAAYAAYAGYGGNCARCC-3') and poly T2 primers as described earlier (Salamon and Palkovics 2005). A PCR product of ~ 1.6 kb was obtained in each case (Fig. S3.), cloned into pGEM®-T Easy vector (Promega, Madison, WI, USA) and transformed into E. coli DH5α strain. The obtained 1642 nucleotide (nt) sequence encompassing the complete coat protein (CP) was determined (Accession No: OP057214). The virus sequence present in the source and inoculated plants shared 100% nt identity. EcoRV digestion of the PCR products yielded two restriction fragments (369/1273 bp), indicating the presence of a single potyvirus in the infected plant tissue (Fig. S3.). BLASTN analysis of the CP cistron revealed highest nt identity (93.91 %) to meadow saffron breaking virus (MSBV) isolate FR GenBank Acc. No.: AY388995. MSBV was first reported in the Alsace region of France at an INRA research station in cultivated meadow saffron plants showing similar symptoms and the disease reached 100% incidence within a year (Poutaraud et al. 2004). Potyviruses are transmitted mechanically and by aphids (Inoue-Nagata et al. 2022). The spread of MSBV could lead to the infection and decline of the population of Colchicum in protected ecosystems. To our knowledge, this is the first report of MSBV on wild meadow saffron plant from a strictly protected Natura2000 site at a Hungarian National Park.

First report of Alternaria alternata causing leaf spot on Hibiscus mutabilis in China

Hibiscus mutabilis L. is a deciduous shrub native to China. Because of its ornamental value and ecological value, it has been widely cultivated in many provinces of China (Shang et al. 2020). In October 2021, leaf spot on Cotton rose with about 80% disease incidence was observed in Jinan (116.9408° N, 36.6688° E), Shandong, China. Symptoms first appear on leaves with small dark brown spots surrounded by yellow halos, then become irregular necrotic spots with yellow halos. The diseased leaf samples were packed in paper bags and transferred to the laboratory for isolation. The infected leaves were firstly surface-sterilized for 45 seconds in 75% ethanol, 1 min in 1% sodium hypochlorite, and 1 min in 75% ethanol, then rinsed for 2 min in distilled water and blotted on dry sterile filter paper. Then samples were cut into 5 × 5 mm pieces using a double-edge blade, and transferred onto the surface of potato dextrose agar (PDA; 200 g potatoes, 20 g dextrose, 20 g agar per L) and malt extract agar (MEA; 30 g malt extract, 5 g mycological peptone, 15 g agar per L), and incubated at 25 ◦C to obtain the pure culture. After 7 days of incubation, greyish fungal colonies appeared on PDA. Single-spore isolation method was employed to recover the pure cultures for six isolates. The colonies initially produce light gray aerial hyphae, which turn dark gray as they mature. Conidiophores (n=50) single or in small groups, straight or curved, sometime geniculate, 20-50 nm long, with scars. Conidia (n=50) were obclavate to pyriform and measured 15 to 60 μm long, 4 to 16 μm wide with 0 to 3 longitudinal, and 1 to 6 transverse septa with short beak (2-30 μm). The morphological characters matched those of Alternaria alternata (Simmons 2007). DNA was extracted from the fungal colonies using a Ezup Column Fungi Genomic DNA Purification Kit. The internal transcribed spacer (ITS) region, glyceraldehyde-3-phosphate dehydrogenase (GAPDH), and translation elongation factor 1-alpha (tef1) were amplified with the primers ITS1/ITS4 (White et al. 1990), gpd1/gpd2 (Berbee et al. 1999) and EF1-728F/EF1-986R (Carbone & Kohn 1999). The obtained sequences were deposited in the GenBank (ITS: OM759881 and OM759882, GAPDH: ON376732 and ON376733, tef1: ON376730 and ON376731). The morphological characteristics and molecular analyses of the isolate matched the descriptin of A. alternata. To perform pathogenicity test, The seedlings of twenty 2-year-old potted H. mutabilis plants were inoculated by spraying conidial suspension at the concentration of 1 × 106 conidia/ml on both sides of leaves and ten plants sprayed with sterile water served as control. The test was repeated three times. All plants were covered with polyethylene covers and kept under the greenhouse at 26 ± 1 ℃. After six days, the inoculated plants showed the same symptoms as the original diseased plants and the controls remained asymptomatic. The fungal pathogen was reisolated from the artificially infected plants and confirmed as A. alternata based on morphocultural characteristics and PCR assays. The results indicated that A. alternata is a causal agent of the disease. The leaf spot disease of cotton rose caused by Nigrospora oryzae has already been reported from Sichuan, China (Han et al. 2021). To our knowledge, this is the first report on the presence of A. alternata affecting H. mutabilis plants. The identification could provide relevant information for adopting appropriate management strategies to control the disease.

Gray Blight Disease on Euonymus japonicas Caused by Pestalotiopsis disseminata in China

Euonymus japonicas is widely planted as an important landscape species throughout China. In June 2021, a serious gray blight disease was detected on E. japonicas in Henan Province (32°30'58" N, 112°19'44" E), causing severe defoliation of infected trees with a foliar disease incidence of 52 to 70% (n = 100). Gray spots initially appeared on leaves, gradually expanded into irregular white blotches with dark brown borders, eventually leading to wilting and death of the leaves. The junctions between the lesion and healthy tissue of infected leaves were cut into 3 × 3-mm pieces, surface sterilized with 1% NaClO solution for 1 min, rinsed in sterile water, and placed on PDA plates with 50 μg/ml of streptomycin. Three isolates (HY94, HY95, and HY98) were selected for subsequent experiments. The colonies reached 80-85 mm diam after 7 days at 25°C, with undulated margins, white to pale in color, with moderate aerial mycelium on the surface. Conidiomata were globose, solitary, and dark black. Conidia were ellipsoid, straight to slightly curved, 4-septate, 19 to 26.4 × 5 to 7.5 μm (n=100). The apical cell was cylindrical and hyaline, with 2 to 3 tubular apical appendages, unbranched, filiform, 2.5 to 3.5 μm in length. The basal appendage was single, unbranched, centric, 1.5 to 3 μm long. The characteristics were close to those of Pestalotiopsis spp. (Maharachchikumbura et al. 2013). The genomic DNA was extracted, and the rDNA internal transcribed spacer (ITS), the β-tubulin gene (TUB), and the translation elongation factor 1-alpha gene (TEF1) were amplified by primers ITS1/ITS4, Bt2a/Bt2b, and EF1-728F/EF1-986R, respectively (Carbone and Kohn, 1999). Sequences were submitted to GenBank with accession numbers OL840327-OL840329(ITS), OL961454-OL961456(TUB), and OL961448-OL961450 (TEF1). BLASTn analyses of ITS, TUB, and TEF1 sequences exhibited 99.46, 99.05, and 96.53% similarity to the sequences of Pestalotiopsis disseminata strain MEAN1166 (ITS, 548/551 bp; MT374688) (Silva et al. 2020), PSH2000I-066 (TUB, 418/422 bp; DQ333575), and TAP29O082 (TEF1, 250/259 bp; AB453850), respectively in GenBank. The three isolates formed a clade with the type strains, MEAN 1166 and MAFF238347 of P. disseminata in phylogenetic trees, being clearly seperated from other Pestalotiopsis spp. Based on morphological and molecular evidence, the pathogen was identified as P. disseminata (Maharachchikumbura et al. 2011). To fulfill Koch's postulates, pathogenicity was tested with three isolates. Ten healthy leaves of 5-year-old intact plants were used per isolate and inoculated with mycelial plugs on both nonwounded and wounded leaves. Control leaves were inoculated with agar plugs. The inoculated plants were placed at 28°C in a greenhouse (90% relative humidity). Distinct lesions were observed after 10 days. The pathogen reisolated was identical to that of the original cultures according to phenotype and ITS sequences. The control leaves showed no obvious symptoms. P. disseminata is known to cause disease on several important plants in China, such as Camellia japonica (Zhang et al. 2012), Pinus armandii (Hu et al. 2007), and Tripterygium wilfordii (Kumar et al. 2004). This is the first report of gray blight disease caused by P. disseminata on E. japonicas in China and worldwide. The fungal pathogen identification will provide valuable information for prevention and management of gray blight disease associated with E. japonicas.

First report of Leek yellow stripe virus, Onion yellow dwarf virus, and the putative allium polerovirus A in elephant garlic (Allium ampeloprasum) in Brazil

Five elephant garlic plants (Allium ampeloprasum L.) showing leaf symptoms of chlorotic streaks and mosaic (Figure 1A and B) were collected, in September 2021, in an experimental area in municipality of Rio do Sul (27°11'07"S, 49°39'39"W), State of Santa Catarina, Brazil. Total RNA was extracted using TRIzol® reagent (Invitrogen, USA), according to the manufacturer's instructions to investigate viral infection. The RNA from all five plants were pooled into a single sample for cDNA library construction with the TruSeq Stranded Total RNA with Ribo-Zero Plant (Illumina) kit, which was then sequenced on the Illumina HiSeq2500 platform (Proteimax Biotechnology LTDA). After high throughput sequencing (HTS), 49 million raw reads (each 151nt) were generated. They were trimmed with the BBduk tool and de novo assembled with the Tadpole assembler tool (Geneious Software version 2022). A total of 28,345 contigs were generated and searched against the NCBI virus genome database using BLASTn and BLASTx, with positive results for two potyviruses, leek yellow stripe virus (LYSV), onion yellow dwarf virus (OYDV), and the putative polerovirus allium polerovirus A (APVA). The trimmed reads were mapped with the BBmap tool (Bushell 2014), using reference sequences for LYSV (NC_004011), OYDV (NC_005029), and APVA isolate Won (MH898527). A total of 806,060 reads were mapped, resulting in the nearly complete genome of LYSV (isolate RDS22-2, 10,268 bp, ON565071), which shared the highest (89.41%) nucleotide (nt) identity with LYSV isolate MG (KP258216). The nearly complete genome of OYDV (isolate RDS22-1, 10,519 bp, ON565070) was assembled using 311,467 reads, being 90.21% nt identical to OYDV isolate G-118 (KF632714). The APVA genome (isolate RDS22-3, 4,367 bp, ON565072, Figure 1C) was assembled from 116,303 reads and it shared the highest (90.73%) nt identity with APVA isolate Won. Subsequently, each sample was RT-PCR screened separately for potyviruses and poleroviruses, using the generic primer pairs NIb2F/NIb3R (Zheng et al., 2010) and Pol-G-F/Pol-G-R (Knierim et al., 2010), respectively. Amplified DNA fragments with approximately 350 bp and 1000 bp were obtained for potyviruses and poleroviruses, respectively, and were sent for Sanger sequencing (ACTGene, Alvorada, Brazil). The Sanger derived partial sequences shared 98 to 100% nt identities with corresponding HTS-derived sequences. The most common virus was LYSV, which was found in three of the five tested samples, whereas OYDV and APVA were only found in one sample each. The plants were also screened with specific primers for each virus, and none of the samples revealed mixed infections. Elephant garlic is primarily utilized for industrial garlic production in several countries, and it is now being researched in Brazil for the same purpose. It can be observed from this study that elephant garlic is susceptible to two of the most common viruses in garlic (LYSV and OYDV), which must be considered in the future while developing resistant varieties or in using thermotherapy and shoot tip/meristem culture to recover virus-free cultivars. LYSV and OYDV have already been described in Brazil infecting Allium sativum (Kitajima 2020). The only complete APVA sequence available is from China (Isolate Won), but no further characterization of the virus has been performed and published. The occurrence of this virus in Brazil highlights the importance of further research to obtain a more robust virus characterization.

First report of alstroemeria mosaic virus infecting Alstroemeria in Korea

Alstroemeria, a member of the Alstroemriaceae family, is a popular cut flower plant with a long-base life and a wide variety of flower colors. It is widely cultivated in many countries, especially in Central and South America. However, numerous viruses such as alstroemeria carlavirus (AlCV), alstroemeria mosaic virus (AlMV), cucumber mosaic virus (CMV), tomato spotted wilt virus (TSWV), alstroemeria streak virus (AlSV), and impatiens necrotic virus (INSV) can infect Alstroemeria and significantly decrease its yield (Kim, 2020). Among these viruses, AlMV is well known to cause an endemic viral disease in the Netherlands (Corine M. et al. 1992). AlMV is a member of the genus potyvirus in the family Potyviridae, one of the most widely distributed families of plant viruses. In 2021, symptomatic alstroemeria plants showing interveinal leaf streaking with elongated light green and chlorosis of leaves were identified from farms in a greenhouse in Gwangju, South Korea. Potyvirus-like particles (approximately 750-800 nm in length) were observed from sap of the symptomatic plants by electron microscope (Supplementary Fig. 1). To confirm virus infection, total RNA was extracted from an alstroemeria leaf using a Beniprep® Super Plant RNA extraction kit (IVT7005, Invirustech Co., Korea). A cDNA library was synthesized and analyzed by high throughput sequencing (HTS) using an Illumina NovaSeq6000 S4 sequencer. A total of 48,072,240 raw reads were obtained after quality filtering with FastQC. Remaining sequences were de novo assembled into contigs with a Trinity assembler. Nucleotide blast analysis of contigs against NCBI viral reference database revealed that 24 assembled contigs (> 1,000 bp) were sequences of AlMV. To confirm AlMV detection, raw reads were mapped to known AlMV complete genome (9,774 bp) using Bowtie2 program. Results showed that a total of 4,698,112 reads were mapped. A consensus sequence (9,778 bp, accession no. LC709275) was then obtained. To verify the presence of AlMV, RT-PCR assay was conducted with AlMV's CP gene-specific primers: AlMV-F (5'-CACGAGGCTGTGAAACAAGC -3') and AlMV-R (5'- CCAGGCGACACGGCTAAATA-3'). PCR products of the expected size (538 bp) were cloned, sequenced, and subjected to GenBank BLASTn search. A 538 bp partial CP sequence was used for BLAST analysis which revealed that it shared 100% identities with the consensus sequence (LC709275) and 96.99~98.76% nucleotide identities with four AlMV isolates (MK440140, NC043135, MT892648, DQ295032). Phylogenetic analysis based on partial CP sequences of representative members of potyviruses (family Potyviridae) using 1,000 bootstrap replicates based on either neighbor-joining or Kimura 2 parameter methods in MEGA-X revealed that AlMV isolate JNU-2 was grouped together with the four known AlMV isolates (Supplementary Fig. 2). To determine the incidence of AlMV in a greenhouse, 30 alstroemeria samples were collected and tested by RT-PCR. Results showed that 23 samples were positive for AlMV by PCR-gel electrophoresis and Sanger sequencing, suggesting a high incidence of AlMV infection. To the best of our knowledge, this is the first report of natural infection with AlMV in Alstroemeria in Korea. Further surveys of AlMV infection in greenhouses will help us prevent the spread of this viral disease in Alstroemeria.

The identification and first report of Alternaria alternata causing leaf spot on Gaillardia pulchella Foug. in Shandong province of China

Gaillardia pulchella Foug., belonging to the family Asteraceae, is an annual herb commonly seen in tropical America and China. It is often used as ornamental flowers because of its bright color, long flowering period and simple cultivation and management. In June 2021, leaf spot on G. pulchella with ∼40% disease incidence was observed in Laoshan scenic spot of Qingdao, Shandong Province, China. Initial symptoms on leaves appeared as light yellow to brown round or oval spots with dark brown borders, and the lesion area gradually expanded and the color deepened with the development of the disease. Small tissue samples collected from the infected lesions were surface-sterilized with 70% ethanol for 30 s, then rinsed with 2% sodium hypochlorite (NaClO) for 60 s, and finally rinsed with sterilized water three times. All the samples were transferred to potato dextrose agar (PDA) medium and incubated at 25℃ in the dark for 5 days (Zhu et al. 2013). A total of 9 isolates were obtained from the 11 selected tissues of symptomatic leaves. Afterward, all the single spore isolates were transferred onto potato carrot agar (PCA) plates (Mirkova 2003). After 7 to 10 days of incubation on PCA at 25℃ in the dark, colonies had a cottony mycelium with round margins, colored in white to gray. To test pathogenicity, six healthy G. pulchella plants were inoculated with mycelial plugs of the above pure cultures from a 7-day-old culture grown on PCA, while six germfree PCA plugs were served as negative controls. All the inoculated plants were set in greenhouse incubator at 25℃ and 80% relative humidity. Following 5 days incubation, brown spots began to appear on the sites of all inoculated leaves with mycelial plugs, while all the negative controls inoculated with sterile PCA plugs remained healthy. Infected lesions were separated and cultured as the same as those isolated in the field, and the same isolate was again microscopically identified, fulfilling Koch's postulates. 5 isolates were characterized, the colony margins of single spore isolate were round with gray or black aerial mycelia. Conidia were clustered and unbranched with 1 to 4 septa, colored in light or dark brown, shaped in obclavate or ellipsoid with short conical beak at the tip, dimensions varied from 14 to 51 μm (length) × 4.5 to 11 μm (width). The described morphological characteristics were consistent with Alternaria alternata (Simmons 2007). For further identification of molecular characterization, the genes of Chitin synthase (CHSD), RNA polymerase II second largest subunit (PRB2), Tsr1 ribosome biogenesis protein (Tsr1) and glyceraldehyde 3-phosphate dehydrogenase (GAPDH) were obtained by PCR amplification with the primer pairs CHSDF1/CHSDR1, PRB2DF/PRB2DR, Tsr1F/Tsr1R and GAPDHF1/GAPDHR1 (Damn et al. 2019; Lawrence et al. 2013), respectively. The sequenced genes (GenBank accession nos. ON660874, ON660875, ON660876 and ON660877) had more than 99% nucleotide identity with the corresponding genes (GenBank accession nos. KY996470.1, MN304718.1, KY996472.1 and MN158133.1) of the reference strains of A. alternata in GenBank, and the re-inoculated and re-isolated strains have the same results which were repeated three times. The causal agent occurred on G. pulchella was identified as A. alternata based on the morphological and molecular characteristics. To our knowledge, this is the first record causing leaf spot on G. pulchella by A. alternata in China.

Culm blight on Phyllostachys aureosulcata 'Spectabilis' caused by Apiospora locuta-pollinis in China

Phyllostachys aureosulcata McClure 'Spectabilis' C.D. Chu. et C.S. Chao is predominantly native to subtropical to warm temperate areas and is widely cultivated for landscaping in China (Neményi et al. 2015). In November 2020 (10 - 16 ℃), culm blight symptoms were observed on P. aureosulcata 'Spectabilis' in Wangjiang Tower Park (all kinds of plant areas are about 9.8 ha), Chengdu City (104°09'30.42″ E, 30°63'18.89″ N). Fifty plants were surveyed, and disease incidence was recorded as approximately 30%. Initially, chlorotic necrotic patches appeared on the culms, and gradually the patches became white, expanded to both ends, and encircled the whole culm with black edge and conidiomata, which eventually led to wilt and death. Five samples from different bamboos were collected and one of them were used for morphological observation. Five single conidia isolates were carried out on potato dextrose agar (PDA) at 25±1℃ (Chomnunti et al. 2014). Colonies were initially white and then yellowish in the center with abundant aerial mycelia. On the culm, conidiomata were dry, black, and filamentous. Conidiophores were reduced to conidiogenous cells. Conidiogenous cells were smooth, hyaline, ampulliform to doliiform. Conidia were ellipsoid to globose, dark brown, smooth and aseptate, measuring 5.2 to 9.4 × 4.4 to 7.3 μm, (=8.2 × 6.5μm, n=50). On the PDA medium, conidia were globose to subglobose, olive green to pale brown, and smooth, larger than those from the host in size, measuring 9.0 to 18 × 7.5 to 9.5 μm ( =36.6 × 18.8 μm, n=50). These asexual structures were extremely similar to Apiospora locuta-pollinis (F. Liu & L. Cai) X.G. Tian & Tibpromma (Zhao et al. 2018). DNA was extracted from the representative strain (SICAUCC 22-0036), and the internal transcribed spacer (ITS), translation elongation factor 1-alpha (tef1-α), beta-tubulin (tub2), 28S large subunit rDNA (LSU) were amplified and sequenced with primers ITS1/ITS4 (White et al. 1990), EF1-728F (Carbone & Kohn 1999)/EF2 (O'Donnell et al. 1998), T1 (O'Donnell & Cigelnik 1997)/Bt2b (Glass & Donaldson 1995) and LR0R/LR5 (Rehner & Samuels 1994). The newly generated sequences were deposited in GenBank with accession nos. ON228609 (ITS), ON324018 (tef1-α), ON237657 (tub2), and ON228665 (LSU). Nucleotide blast showed 98.97%, 100% and 99.46% identities with A. locuta-pollinis (LC11683, ex-holotype) (accession nos. MF939595, MF939622, MF939616), and LSU data missing. Phylogenetic analyses using maximum likelihood showed a 92% bootstrap support value in a clade with A. locuta-pollinis (Fig 2). Eight healthy plants (2-year-old) were used for the pathogenicity test. Culms of four healthy bamboos were wounded via sterile double-edged blade and sprayed with conidial suspension (105 conidia/ml) prepared from 4-week-old cultures that were incubated on PDA at 25℃. The other four bamboos were sprayed with sterile distilled water as controls. Inoculated plants were placed in a growth chamber (25℃, 90% relative humidity, 12-h photoperiod). About 60 days later, necrotic patches similar to those observed in the field were found on the inoculated culms, and no symptoms were observed on the controls. The pathogen was reisolated from the diseased culms with identical morphology as previously described. To our knowledge, this is the first report of culm blight on P. aureosulcata 'Spectabilis' caused by A. locuta-pollinis. The risk of this pathogen needs further evaluation, and effective control measures should be taken.

First Report of Blight Caused by Rhizoctonia solani AG4-HGI on Pinellia ternata in Guizhou, China

Pinellia ternata (Thumb.) has been used for over 1000 years as a traditional Chinese herbal medicine (Ying et al. 2007) and is widely cultivated in Guizhou Province, China. It is cultivated over an area of 2000 hectares, and is of great value to underdeveloped regions. In April 2020, blight was observed in a field of P. ternatain Bijie County, Guizhou Province, China (27°30'N, 105°28'E). Around 20 hectares of P. ternata were surveyed and the disease incidence ranged from 10 to 12%. The disease symptoms included light brown lesions formed on the stems near the soil line. The color of the lesions became darker, and the stems became constricted around the lesions and broke, associated with the leaf blight. To identify the causal agent of this blight, 22 diseased plants (about 30 d-old） were collected, the margins of the infected parts were cut into small pieces (5 mm) and surface disinfested with 1% NaOCl for 10 min, 75% ethanol for 30 s, and rinsed three times in sterile distilled water. The pieces were blotted dry with sterile filter paper and placed on potato dextrose agar (PDA, Hopebio, China), incubated at 28℃ in darkness until fungal hyphae growth was visible. Sixteen cultures with different morphologies were recovered from the samples. When representative isolates of each culture type were inoculated onto plants, one produced similar blight symptoms. The representative isolate was called CD-1. The colony color was first white but turned light brown after grown on PDA for 6-7 d, and produced dark brown sclerotia. The hyphae were branched at right angles, with a slight constriction at the base of the branches and a septum near the junction where the branch separates from the main hyphae. Hyphal cells were stained with 0.5% Safranin O and 3% KOH and were observed to be multinucleate. These morphological features indicated that CD-1 likely is R. solani (Sneh et al. 1991). When paired with tester strains AG1 and AG4(provided by Dr. Genhua Yang, Yunnan Agricultural University). CD-1 showed anastomosis with isolate of AG4 (Fenille et al. 2002). Genomic DNA was extracted from the isolate (Thangaraj et al. 2018) using a fungal genomic DNA extraction kit (Tiangen, China). The internal transcribed spacer (ITS) regions were amplified using the primers ITS1/ITS4 (White et al. 1990). A 535 bp fragment was amplified that showed 99% coverage and 99.4% identity with an isolate of R. solani AG4-HGI (GenBank: HG934417). The gene sequence was deposited in GenBank as accession #OL518945. Pathogenicity tests were performed using 30 d-old plants planted in sterilized soil in pots. Cut mycelial discs (diameter 6 mm) from 3-day-old PDA cultures and placed beside stems of 21 healthy plants. Nine plants treated with agar plugs were control samples. Inoculated plants were maintained at 24 ± 5℃ in a green house and watered every two days with sterilized water. Typical blight symptoms developed on the inoculated plants at d 3-5 post inoculation, whereas the control plants remained healthy. The experiments were repeated three times, and the isolates was re-isolated from the inoculated plants and identified as R. solaniAG4 by morphological features and molecular method. R. solani has been reported to cause blight of many plants such as coffee (Ren et al. 2018) and sesame (Cochran et al. 2018). To the best of our knowledge, this is the first report of R. solani AG4-HGI causing disease on P. ternate, both in China and worldwide. This finding suggests that this pathogen may cause a threat to cultivation and production of P. terenata.

First report of Cladosporium cladosporioides causing leaf blight on Sambucus chinensis in China

Sambucus chinensis, belonging to the Caprifoliaceae family, is an economically large herb plant that is widely cultivated in southern China for its good ornamental characteristics, edible properties, and medicinal values. In July 2021, symptoms of leaf spot were observed on Sambucus chinensis plants in two fields of Chongqing Medicinal Botanical Garden (29º8'26" N, 107º13'23" E) in Nanchuan city, Chongqing, China. Disease incidence was approximately 35 and 50% for each field. The symptoms were initially yellow or black irregular spots on leaves, and then increased to larger dark brown lesions. Finally, the entire infected leaf was blighted, withering, curl and abscission. Ten blight leaves were randomly sampled from fields. Tissues were cut into small pieces and surface sterilized with 75% ethanol for 30 s and sterilized in 2% sodium hypochlorite for 2 min, rinsed thrice with sterile distilled water, plated on potato dextrose agar (PDA) plates, and incubated at 25°C for 7 days in the dark. Later, 20 isolates were obtained from the infected leaves and had similar characteristics. Three isolates were randomly selected (CQ81, CQ82, CQ83) for the further study. Colonies on PDA were olive-green to brown with a velvety texture. Conidia (n=30) were pale- to olive-brown, smooth to verruculose and produced in long, branched chains which were easily disarticulate, single celled, and elliptical to limoniform, and measured as 2.51~4.29 × 1.63~2.14 μm. Conidiophores were solitary, straight or flexous, often unbranched. The DNA of three isolates were extracted and the internal transcribed spacer (ITS) region and translation elongation factor 1-alpha (TEF1-α) were sequenced using primer pairs ITS1/ITS4 (White et al. 1990) and EF1-728F/EF1-986R (Carbone and Kohn 1999), respectively. The sequences of three isolates were 100% identical, and one representative isolate CQ82 were deposited in GenBank (ON387641, ITS; and ON409522, TEF). BLASTn analysis of these sequences showed 99 to 100% nucleotide identity with the sequences of C. cladosporioides CPC 14705 in Korea (Bensch et al. 2010). Phylogenetic analysis using Neighbor-joining method and concatenated sequences (ITS +TEF1) with MEGA7 placed isolate CQ82 in C. cladosporioides with 99% bootstrap support. On the basis of morphological and molecular characteristics, the isolates were identified as C. cladosporioides (Bensch et al. 2010; Nam et al. 2015). A total of sixteen healthy potted plants of S. chinensis were conducted for the pathogenicity test. Eight plants were selected and one shoot of each plant was randomly used for inoculation. Leaves from the shoot of each plant were brushed with 106 conidia/ml suspension of isolate CQ82. Another 8 plants were performed in the same procedure, inoculated with sterile distilled water as control. All plants were covered with plastic bags for two days and then arranged in a greenhouse with 80% relative humidity at 25°C. The pathogenicity test was repeated thrice. After 15 days inoculation, the similar symptoms were observed on the inoculated leaves, whereas controls remained healthy. The pathogen was reisolated from blight tissue and identified as C. cladosporioides by the methods described above. Although this fungus was previously reported to cause leaf disease on many plants (Meneses et al. 2018; Sun et al. 2017), this is the first report of C. cladosporioides causing leaf blight on S. chinensis in China. This study will establish a foundation for controlling the disease.

Leaf Spot Disease on Euonymus japonicas Caused by Nigrospora oryzae in China

Euonymus japonicas belong to the family Celastraceae and is native to Japan. This ornamental plant has been widely introduced for cultivation as a hedge plant in China. From August to October 2021, severe leaf lesions were observed on E. japonicas in Meicheng garden in Nanyang (32°59'42"N, 112°33'13"E), Henan Province, China. The disease had very wide coverage in the surveyed areas, with foliar diseases reaching 50%-69% (n=200). The early symptoms were yellow or brown specks on the leaves, mostly at the tip and margin of the leaves. Then the specks gradually expanded into round amorphous and became dark brown, eventually leading to large irregular or circular lesions and even branch necrosis. Twenty symptomatic samples were collected from several individual plants, and the junction areas between infected and healthy tissues were cut into 5×5 mm pieces. The tissues were sterilized in 75% ethanol for 30 seconds and 1% NaClO solution for 1 min, rinsed thrice in sterile water and placed on potato dextrose agar (PDA) plates supplemented with 50 µg/ml of streptomycin, incubated at 25°C for 3 days. The edges of the colony were cut and transferred to new PDA plates for purification. These strains showed similar phenotypes in morphological characters. Three representative purified strains (HY12, HY16, and HY17) were used for further study. Colonies were fast-growing, massive sparse aerial hyphae, initially white, later turning gray and black. Hyphae were branched, septa, and transparent. Conidia were single-celled, dark black, oblate, or nearly spherical, and measured 10.7 to 15.4 μm × 9.8 to 15.5 μm in diameter (n=100). For molecular identification, the rDNA internal transcribed spacer (ITS), the β-tubulin gene (TUB), and the translation elongation factor 1-alpha gene (TEF1) were amplified from genomic DNA by primers ITS1/ITS4, Bt2a/Bt2b, and EF1-728F/EF1-986R, respectively (Carbone and Kohn, 1999). Sequences were submitted to GenBank with accession numbers OL840319, OL840320, OL840321 for the ITS sequences, OL961451, OL961452, OL961453 for the TUB sequences, and OL961445, OL961446, OL961447 for the TEF1 sequences of the strains HY12, HY16, and HY17, respectively. BLASTn analyses of these sequences exhibited 99 to 100% identity to Nigrospora oryzae strains 62L1, LC6923, and DP-J2 (MZ151384 of ITS, KY019581 of TUB, and MW562242 of TEF1). These morphological features and molecular identification indicated that the pathogen possessed identical characteristics as N. oryzae (Berk. &Broome) Petch. Pathogenicity was tested through in vivo experiments. Mycelial plugs of the pathogen strains were inoculated on the wounded leaflets, meanwhile, agar plugs served as blank controls. Five 2-year-old plants were grown in pots in a climate incubator maintained at a temperature of 28°C and relative humidity of approximately 90%. Symptoms consistent with those previously described were observed on the inoculated leaves of four plants after 3 to 7 days while the control plants remained healthy. The strains of N. oryzae were reisolated from the symptomatic inoculated leaves, fulfilling Koch's postulates. N. oryzae is known to cause disease on a variety of ornamental plants in China, such as purple blow maple (Sun et al. 2011), cleyera (Wang et al. 2017), cotton rose (Han et al. 2021), and Costus speciosus (Sun et al. 2021). To our knowledge, this is the first report of N. oryzae leaf spot on E. japonicas in China. This identification research will be helpful for subsequent disease control and field management of hedge plants.

First Report of Leaf Blight Caused by Colletotrichum karsti on Peppermint (Mentha x piperitavar. citrata) in Mexico

Spearmint (Mentha x piperita var. citrata (Ehrh.) Briq.: Lamiaceae) is an aromatic herb widely cultivated owing to its industrial properties. In June 2020, symptoms of leaf blight were observed on 1,500 peppermint plants in a commercial nursery located in Cuautla (18°52'18"N 98°57'58"W), Morelos, Mexico. The incidence of the disease was 89%. Symptoms were initially observed as irregular, small black necrotic spots, that grew rapidly until the leaves were blighted. Fungal isolation was done using diseased leaf tissue on potato dextrose agar (PDA) as described by Ayvar-Serna et al. (2020) and Colletotrichum-like colonies were obtained. Six isolates were purified by single spore culture and only a single morphotype was obtained. One isolate was used for pathogenicity tests, morphological characterization, and multilocus phylogenetic analysis. The isolate (accession no. UACH449) was deposited in the Culture Collection of Phytopathogenic Fungi of the Department of Agricultural Parasitology at the Chapingo Autonomous University. Colonies in PDA grow at a rate of 7.0-10.0 mm/d. After 14 days, the colony was white to orange, and conidia (n =100) were hyaline, cylindrical, and straight with rounded ends, measuring 15.0-17.0 × 4.5-6.5 μm. Appressoria were brown and bullet-shaped. In 28-day-old colonies, the formation of perithecia was observed. Asci were hyaline, unitunicate, 8-spored, fasciculate, and cylindrical to clavate. Ascospores (n =100) were hyaline, unicellular, allantoid, inaequilateral, often straight on the inner side, apices rounded, arranged biseriately within the asci, and measured 14-19 × 4.0-7.5 μm. Morphological features of the isolate placed it tentatively within the Colletotrichm boninense species complex (Damm et al. 2012). For molecular identification, genomic DNA was extracted, and the internal transcribed spacer (ITS) region (White et al. 1990), partial sequences of calmodulin (CAL), glyceraldehyde-3-phosphate dehydrogenase (GAPDH), and actin (ACT) (Damm et al. 2012) genes were amplified and sequenced. A phylogenetic tree including published ITS, CAL, GAPDH, and ACT data for Colletotrichum species was constructed and the isolate UACH449 was grouped in the clade of Colletotrichum karsti. Sequences were deposited in GenBank under the accession numbers: ITS, OL825605; CAL, OL855890; GAPDH, OL855891 and ACT, OL855889. Pathogenicity was tested by spraying a suspension of 1 × 10^5 conidia/ml, onto eight healthy peppermint plants 30-days-old var. citrata, while eight control plants were sprayed using sterile distilled water. All plants were kept at 25 +/- 2°C and 70% RH. The characteristic symptoms of the disease were observed seven days after inoculation, while control plants remained symptomless. The pathogenicity test was repeated twice. The fungus was consistently reisolated from the eight inoculated plants and was morphologically identical to that originally isolated from diseased leaves, fulfilling Koch's postulates. To date, this pathogen has not been reported on peppermint (Farr and Rossman, 2022). To our knowledge, this is the first report of Colletotrichum karsti causing foliar blight on peppermint worldwide. According to our field observations, this disease is a threat to the production of peppermint plants.

First Report of Powdery Mildew Caused by Podosphaera fuliginea on Veronica spicata in China

Veronica spicata L. (syn. Pseudolysimachion spicatum Opiz), Plantaginaceae, is a perennial herb and frequently cultivated in gardens as an ornamental plant in China. In June 2017, powdery mildew infections were observed on V. spicata in Jingyuetan National Forest Park (43.80°N, 125.46°E), Changchun, China. A voucher specimen was deposited in the Herbarium of Mycology of Jilin Agricultural University under the accession no. HMJAU-PM91763. The incidence of the disease on leaves and stems was about 30 to 50%. The disease initially appeared as thin white colonies, which subsequently developed into dense effuse white colonies on the plant. Hyphae were flexuous to straight, septate, 3.0 to 8.0 μm wide. Hyphal appressoria were indistinct or nipple-shaped, solitary. Conidiophores (n=30) arise from the upper surface of hyphal mother cells, erect to straight, 133.4 to 176.2 × 7.8 to 10.7 μm. Foot-cells (n=40) were cylindrical, straight or slightly flexuous, 39.1 to 78.5 × 7.4 to 9.7 μm, and followed by 1 to 3 short cells. Conidia (n=45) were catenescent, ellipsoid, oval, or doliiform, with fibrosin bodies, 17.8 to 27.8 × 12.2 to 17.4 μm, length/width ratio 1.3 to 2.1. Germ tubes were produced at the subterminal to lateral part of conidia, straight or sinuous, without a distinct terminal appressorium. The sexual morph was not observed in the collected samples. The morphological characteristics of the asexual morph were consistent with Podosphaera fuliginea (Schltdl.) U. Braun & S. Takam. (Braun and Cook 2012). To confirm the identification, the complete internal transcribed spacer (ITS) region and partial 28S rRNA gene sequences of the pathogen were amplified by semi-nested PCR with the primers ITS5/P3 followed by ITS5/ITS4, and LSU1/TW14 followed by LSU1/LSU2, respectively. The sequences of 566 bp ITS (MF543026) and 609 bp 28S rDNA (MF543027) were obtained and showed 100% identity with P. fuliginea (AB046986, ON073893) on V. spicata from USA (Hirata et al. 2000). Based on the morphological and molecular characteristics, the fungus was identified as P. fuliginea. To perform pathogenicity assays, three healthy annual plants of P. spicatum were inoculated by gently pressing a diseased leaf onto the leaves, with three non-inoculated plants as controls. All plants were placed in a greenhouse at 21 to 29 °C, 60% relative humidity, with 16 h/8 h light/dark cycle. Nine days after inoculation, typical powdery mildew colonies started to appear on the inoculated plants, while the control plants remained symptomless. The morphology of the fungus on the inoculated leaves was identical to that observed on the originally diseased leaves. Powdery mildews on V. spicata (P. spicatum) were previously referred to as Erysiphe (Golovinomyces) orontii in Italy (Garibaldi et al. 2006) and Sphaerotheca (Podosphaera) fuliginea in many countries, such as Poland, Russia, Switzerland, Wisconsin, Ukraine, etc. (Amano 1986; Braun and Cook 2012; Farr and Rossman 2022; Heluta et al. 2011). To our knowledge, this is the first record of P. fuliginea on V. spicata from China and the first report of this species at all. The results of this study provide important information for horticultural management and plant protection in China. Acknowledgements This work was supported by the National Natural Science Foundation of China (31970019, 31670022). References: Amano, K. 1986. Host range and geographical distribution of the powdery mildew fungi. Japan Scientific Societies Press, Tokyo. Braun, U., and Cook, R. T. A. 2012. Taxonomic Manual of The Erysiphales (Powdery Mildews) CBS Biodiversity Series 11. CBS-KNAW Fungal Biodiversity Centre, Utrecht, the Netherlands. Farr, D. F., and Rossman, A. Y. 2022. Fungal Databases. Syst. Mycol. Microbiol. Lab., USDA-ARS. https://nt.ars-grin.gov/fungaldatabases Garibaldi, A., et al. 2006. Plant Dis. 90:831. https://doi.org/10.1094/PD-90-0831C Heluta, V. P., et al. 2011. Ukr. Botan. Journ. 68:585. Hirata, T., et al. 2000. Can. J. Bot. 78:1521. https://doi.org/10.1139/b00-124.

Identification of Neofusicoccum parvum as the causative agent of leaf spot disease on Bletilla striata in China

Bletilla striata (Thunb.) Rchb. f. (Orchidaceae) is an essential traditional Chinese medicinal plant used to treat hemorrhage, swelling, inflammation, ulcers, and pulmonary diseases (Xu et al. 2019). In April of 2020, an unknown leaf spot disease was observed on B. striata in a plantation (~ 0.2 ha) in Nanning, Guangxi province, China. Disease incidence was estimated at approximately 25% (n = 150 plants). The initial symptoms were small brown circular spots, which then expanded into reddish to brown, circular to irregular lesions 5-10 mm in diameter. As the disease developed, the whole leaf became densely covered with lesions. Finally, the lesions coalesced, killing the leaf and resulting in defoliation. To isolate the causal agent, six symptomatic leaves were collected from individual plants. Small pieces (~ 5 mm2) were cut from the margin of the necrotic lesions (n = 18), disinfected in 1% NaOCl for 2 min before rinsing three times in sterile water, and placed on potato dextrose agar (PDA) at 26°C for 3 days. Hyphal tips from the resulting cultures were transferred to PDA to obtain pure cultures. Fifteen isolates were obtained, of which twelve isolates exhibited similar morphology. Colonies on PDA were initially white, then turned dark gray after 7 days. Pycnidia were produced on the surface of PDA after 50 days. Conidia were hyaline, aseptate, ellipsoidal to fusiform, externally smooth, thin-walled, and measuring 11.5 to 15.2 × 4.9 to 6.1 μm (mean ± SD: 13.4 ± 1.0 × 5.4 ± 0.3 μm, n = 60). Morphological features were similar to N. parvum (Phillips et al. 2013). For further molecular identification, the internal transcribed spacer (ITS) region, partial translational elongation factor subunit 1-α (EF-1α), β-tubulin (TUB2) genes were amplified and sequenced using the primer pairs ITS1/ITS4 (White et al. 1990), EF1-728F (Carbone and Kohn 1999)/EF-2 (O'Donnell et al. 1998), and Bt2a/Bt2b (Glass and Donaldson 1995), respectively. Sequences of the two isolates BJ-111.1 and BJ-111.4 were deposited in NCBI GenBank under the following accession numbers: OM348509-10, OM397537-40. The obtained ITS, EF1-α, and TUB2 sequences showed 99% (514/516, and 513/516 bp), 99% (275/276, and 274/275 bp), and 99% (429/431, and 429/430 bp) homology with several GenBank sequences of the ex-type strain N. parvum CMW 9081 (AY236943, AY236888, and AY236917, respectively) (Zhang et al. 2017). In addition, a phylogenetic analysis confirmed the isolates as N. parvum. Therefore, the isolates were identified as N. parvum based on morphological and molecular evidence. Furthermore, pathogenicity tests were carried out on 1.5-year-old B. striata plants. Healthy leaves on six plants (1 leaf per plant) were inoculated with a 10-μl droplet of conidial suspensions (106 conidia/mL). Three plants treated with sterile water served as the control. All plants were covered with transparent plastic bags and incubated in a greenhouse at 26°C with a 12 h photoperiod. Six days post-inoculation, the inoculated leaves showed leaf spot symptoms, while the control plants remained healthy. The experiments repeated three times showed similar results. Finally, N. parvum was consistently re-isolated from the infected leaves and confirmed by morphology and sequencing, fulfilling Koch's postulates. No fungus was isolated from the controls. To our knowledge, this is the first report of N. parvum causing leaf spot of B. striata worldwide. This result will help develop disease management strategies against this pathogen.

First report of Neofusicoccum australe causing dieback of honeybush in the Western Cape, South Africa

Honeybush (Cyclopia spp.) is an indigenous, leguminous member of the Cape fynbos biome growing in the coastal winter rainfall districts of the Western and Eastern Cape Provinces of South Africa (Joubert et al. 2011). Honeybush is used for the production of herbal teas and is harvested from wild-growing and cultivated plantations (du Toit et al. 1998). Very little is known regarding diseases caused by pathogens on this indigenous plant. Only one report of twig dieback on honeybush caused by several Diaporthe Nitschke species have been reported in South Africa (Smit et al. 2021). Several honeybush producers reported poor growth and dieback in their C. subternata plantations in the Western Cape Province, South Africa. Symptoms included twig dieback, branch dieback, death of branches as well as death of entire plants. In April 2008, branches from 8-year-old cultivated plants with dieback symptoms were collected in Stellenbosch. Fungal isolations were carried out from affected material as described by Van Niekerk et al. (2004) which consistently revealed the presence of a Botryosphaeriaceae species. Two isolates were grown on water agar with sterile pine needles and incubated at 25˚C using a 12-hour day/night cycle and near-ultraviolet light. Pycnidia formed after two weeks. Morphological characteristics similar to Neofusicoccum australe (Slippers, Crous & Wingfield) Crous, Slippers & Phillips were observed (Phillips et al. 2013). Conidia were hyaline, aseptate, fusiform with subtruncate bases (16.8-)18.8-22.1(-24.6) × (4.8-)5.3-6.1(-6.4) µm (n=50). Conidiogenous cells were holoblastic, hyaline and subcylindrical to flask-shaped tapering to the apex (11-15 × 2 µm) (n=10). Colonies on potato dextrose agar were light primrose turning olivaceous grey after 7 days with a light-yellow pigment diffusing into the medium. Mycelia was moderately dense with an appressed centre mat. The identity of the isolates was further confirmed by sequencing the ribosomal RNA Internal Transcribed Spacer (ITS) and the elongation factor 1-alpha (EF-1α) gene regions using primer pairs ITS4-ITS5 (White et al. 1990) and EF1-728F-EF1-986R (Alves et al. 2008), respectively. Sequences had a 100% similarity to N. australe ex-type CMW6837 isolate (accessions AY339262 and AY339270) (Slippers et al. 2004). Two isolates (STEU6554 and STEU6557) were deposited in the culture collection at the Department of Plant Pathology at Stellenbosch University and the sequences were submitted to GenBank with accession numbers ON745603, ON745604, ON746573 and ON746574. Pathogenicity tests using the two N. australe isolates were conducted by inoculating two shoots each of three field-grown C. subternata plants with a 4mm colonised potato dextrose agar (PDA) mycelium plug of each isolate on wounds made by a 4mm cork borer (Van Niekerk et al. 2004). A third shoot was inoculated with a uncolonized PDA plug as the negative control. After 12 weeks, brown-black lesions that were significantly longer (average 55.2 mm) than the uncolonized agar plug control (16.1 mm) were observed. Lesions were observed in all three plants. Neofusicoccum australe was re-isolated (van Niekerk et al. 2004) from all inoculated shoots confirming Koch's postulates. The economic impact and damages caused by N. australe as well as its incidence and severity on honeybush in South Africa is unknown. However, the pathogen caused dieback of entire branches and death of plants indicating that it could be an important pathogen of honeybush. Additionally, N. australe is one of the most important disease-causing Botryosphaeriaceae pathogens on a wide range of economical fruit and vine crops globally (Mojeremane et al. 2020). This is the first report of N. australe as a known pathogen causing decline and dieback of C. subternata in South Africa. References: Alves, A. et al. 2008. Fungal Divers. 28:1. du Toit, J. et al. 1998. J. Sustain. Agric. 12:67. Joubert, E. et al. 2011. S. Afr. J. Bot. 77:887. Mojeremane, K. et al. 2020. Phytopathol. Mediterr. 59:581. Phillips, A. J. et al. 2013. Stud. Mycol. 76:51. Slippers, B. et al. 2004. Mycologia 96:1030. Smit, L. et al. 2021. Eur. J. Plant Pathol. 161:565. van Niekerk, J. M. et al. 2004. Mycologia 96:781. White, T. J. et al. 1990. Pages 315 in: In PCR Protocols: A Guide to Methods and Applications. Academic Press Inc, USA. Declaration. The author(s) declare no conflict of interest Acknowledgments. This work benefitted from the financial support of the Agricultural Research Council, Infruitec-Nietvoorbij, South Africa.

First report of Colletotrichum siamense Causing anthracnose on Cinnamomum camphora in Malaysia

Cinnamomum camphora (Lauraceae), commonly known as camphor tree, is widely grown as an ornamental and is used as a source of camphor in Malaysia. In June 2021, leaves of three camphor trees with anthracnose symptoms were collected from a park (6°02'00.8"N, 116°07'18.5"E) at the Universiti Malaysia Sabah in Sabah province. The average disease severity across diseased plants was about 60% with 30% incidence on 10 surveyed plants. The disease severity on disease area of 10 leaves from each three diseased plants was estimated using ImageJ software. The disease incidence was determined based on Sharma et al. (2017). Gray spots were observed primarily on the surface of the leaves. After a week, the spots coalesced into larger patches, and anthracnose developed. Small pieces (5 x 5 mm) of symptomatic leaf tissue from three camphor trees were excised from the margin between healthy and symptomatic tissue. The pieces were surface-sterilized with 75% ethanol for 1 minute, washed with 2% sodium hypochlorite solution for 1 minute, rinsed, and air dried before plating in three Petri dishes with Potato dextrose agar, and incubated for 7 days at 25°C in the dark. After 7 days, all the PDA plates had abundant gray-white fluffy hyphae. Mycelium was dark brown when observed from the underside of the plate. The isolates UMS02, UMS04 and UMS05 were characterized morphologically and molecularly. The conidia were one-celled, cylindrical, hyaline, and smooth, with blunt ends, and ranged in size from 13.9 to 16.3 x 3.8 to 6.1 μm (n = 20). Appressoria were round to irregular in shape and dark brown in color, with size ranging from 7.8 to 9.8 μm x 5.3 to 6.8 μm (n= 20). Genomic DNA was extracted from fresh mycelium of the isolates based on Khoo et al. (2022a). Amplification of the internal transcribed spacer (ITS) region, calmodulin (CAL), actin (ACT), chitin synthase (CHS-1), and glyceraldehyde-3-phosphate dehydrogenase (GAPDH) genes of the isolate was performed using primer pairs ITS1/ITS4, CL1C/CL2C, ACT-512F/ACT-783R, CHS-79F/CHS-354R, and GDF1/GDR1 (Weir et al. 2012). PCR products with positive amplicons were sent to Apical Scientific Sdn. Bhd. for sequencing. Sequences of the isolates were deposited in GenBank as OK448747, OM501094, OM501095 (ITS), OL953034, OM513908, OM513909 (CAL), OL953031, OM513910, OM513911 (ACT), OL953037, OM513912, OM513913 (CHS-1), and OL953040, OM513914, OM513915 (GAPDH). They were 100% identical to ITS (MN296082), CAL (MN525840), ACT (MW341257, MN525819), CHS-1 (MT210318), and GAPDH (MT682399, MN525882) sequences of Colletotrichum siamense. Phylogenetic analysis using maximum likelihood on the concatenated ITS, CAL, ACT, CHS-1 and GAPDH sequences indicated that the isolates formed a clade (82% bootstrap support) to C. siamense. Morphological and molecular characterization matched the description of C. siamense (Huang et al. 2022). Koch's postulates were performed by spraying a spore suspension (106 spores/ml) on leaves of three healthy two-month-old camphor trees, while water was sprayed on three additional camphor trees which served as control. The inoculated camphor trees were covered with plastics for 48 h at 25°C in the dark, and then placed in the greenhouse. Monitoring and incubation were performed based on Chai et al. (2017) and Iftikhar et al. (2022). Symptoms similar to those observed in the field occurred 8 days post-inoculation. No symptoms occurred on controls. The experiment was repeated two more times. C. siamense has been reported causing anthracnose on camphor tree in China (Liu et al. 2022), Citrus spp. in Mexico (Pérez-Mora et al. 2021), and Crinum asiaticum and eggplant in Malaysia (Khoo et al. 2022b, 2022c). To our knowledge, this is the first report of C. siamense causing anthracnose on C. camphora in Malaysia. Our findings expand the geographic range of C. siamense and indicate it could be a potential threat limiting the camphor production of C. camphora in Malaysia.

First Report of leaf spot disease caused by Enterobacter mori on Canna indica in China

Canna indica L. is a popular landscape ornamental herb of family Cannaceae throughout China. This plant has been extensively cultivated for decoration and as an ornamental in China. C. indica was seriously affected by a disease in the garden in spring of 2021 with an incidence of 21.2 to 45.6%, and it caused economic loss to control plant diseases with chemicals. Both young and older leaves developed necrotic lesions with small water-soaked spots on leaves, which then enlarged and were bordered by chlorosis. Symptomatic tissues were collected from Zhanjiang city (21.2N110.3E) and Wuchuan city (21.4N110.7E) in Guangdong province. Three symptomatic leaves from each city were surface disinfected in a 1% hypochlorite solution for 3 mins followed by being rinsed in sterile distilled water for 3 times. Six bacterial isolates originated from six single colonies were recovered from the samples. Colonies were raised and opaque with smooth margins. The bacteria were gram-negative, rod-shaped with sizes ranged from 0.4-0.7 μm wide and 1.2-2.0 μm long, without endospore, and were facultative anaerobes. For molecular identification, the direct colony PCR method (Lu et al. 2012) was used to amplify the 16S rDNA (Moreno et al., 2002), gyrB, leuS and rpoB of 2 selected strains, EM21ZJ1 and EM21WC1 using the primer pairs 27F/1492R, gyrB3/gyrB4, leuS3 /leuS4 and rpoBjt112/ rpoBjt748 respectively (Deletoile et al., 2009). The resulting sequences were deposited in GenBank (ON600470 and ON600471 for 16S rDNA; ON600472 and ON600473 for gyrB; ON600474 and ON600475 for LeuS; ON600476 and ON600477 for rpoB). BLAST searches with the four gene sequences revealed the greatest similarity with the sequences of Enterobacter mori (Zhu et al. 2011). The available complete genome sequences of Enterobacter species, especially type strains, were downloaded and the sequences of the corresponding 4 genes of each genome was extracted by Bioedit software. The concatenated sequences were aligned by Mega 11.0 with the neighbor-joining method. Multilocus sequence typing analysis showed that the concatenated sequences of the 2 isolates were clustered with E. mori with 100% bootstrap value. The 2 isolates were selected for pathogenicity tests to fulfill Koch's postulates. Six plants at three- to five-leaf stage were inoculated with each isolate separately, 2 sites of each leaf were inoculated, one site was wounded with a sterile needle and the other was not. The 2 sites of each leaf were covered with a piece of cotton drenched with 200 µl bacteria suspension (108 CFU/ml) from 2 isolates separately. Control plants were inoculated identically except Luria-Bertani (LB) medium was used to drench the cotton. Inoculated plants were placed in an incubator at 25°C, and 80% humidity under a 12-h light/dark cycle for 7 days. After 3 days of incubation, water-soaked yellow spots were observed in all the inoculated plants in both wounded and unwounded sites, except the negative control. The water-soaked yellow spots enlarged and became necrotic that matched those seen in garden. The pathogenicity tests were conducted three times with similar results. The bacteria were then reisolated from the lesions and found to have the same colony morphology and 99.9% identity of 16S rDNA sequences as those of the inoculum. According to morphological and sequence analysis, the pathogen was identified as E. mori. To our knowledge, this is the first report of disease of C. indica caused by E. mori.