First Report of Anthracnose on Euonymus japonicus Thunb. Caused by a Provisionally Novel Species of Colletotrichum in the Magnum Complex in South Korea

Euonymus japonicus Thunb., also known as the evergreen spindle tree, is an evergreen tree, which is widely planted as a hedge plant along streets in South Korea. In April 2022, severe anthracnose symptoms were observed on the leaves of this tree in Jangsu in the Jeonbuk Province of the country (35°43'49.44″N, 127°34'53.7″E). About 80% of the leaves of each affected tree within a 0.03-ha area showed incidence of the disease on approximately 30 trees were planted along the roadside (~30 m). These symptoms typically included circular or irregularly shaped whitish-gray lesions with a diameter of 2.0 to 3.0 cm. In cases where some leaves were severely affected, larger blotches formed. To isolate the pathogen, about ten leaves showing anthracnose symptoms on each tree were randomly selected and brought to the laboratory. Fungal isolations were made from acervuli filled with conidial masses on infected evergreen tissues, followed by plating onto 2% potato dextrose agar (PDA) as well as incubated at 25℃. On the PDA, colonies were circular, raised, green-grey or dark grey, and had a distinct white margin. The conidia were single-celled, transparent, cylindrical with rounded ends, had smooth walls, with a length ranging from 12 μm to 16.7 μm and a width raging from 4 μm to 6.5 μm (av. = 14.1 X 5.0 μm, n=40). Of those that were successfully recovered with approximately 90% frequency, two monoconidial isolates were deposited to the culture collection at Chungnam National University in South Korea (Accession number: CDH059-060). To ensure the identity of the fungus, genomic DNAs were extracted from the selected isolates, CDH059-060, and were sequenced. This was achieved based on partial sequences of the internal transcribed spacer (ITS), actin and beta-tubulin (TUB2) gene regions which were amplified using ITS1F / ITS4 (Gardes and Bruns 1993; White et al. 1990), ACT-512F / ACT-783R (Carbone and Kohn 1999), and T1 / Bt2b (O'Donnell and Cigelnik 1997; Glass and Donaldson 1995) primer pairs, respectively. The resulting sequences were deposited to GenBank (OR984424-425) for ITS, (OR996289-290) for actin, and (OR996291-292) for TUB2. For a phylogenetic analysis, sequences from different gene regions (ITS, actin and TUB2) retrieved from GenBank were aligned, concatenated, and analyzed as a single dataset based on a maximum likelihood analysis. The phylogenetic result revealed that the fungus isolated in this study was positioned in a clearly distinct lineage, provisionally representing an undetermined species of Colletotrichum, which is most closely related to Colletotrichum liaoningense (Y.Z. Diao, C. Zhang, L. Cai & X.L. Liu, CGMCC3.17616 (KP890104 for ITS, KP890097 for actin, and KP890111 for TUB, Diao et al. 2017). Sequence comparisons revealed that this pathogen differed from C. liaoningense at 20 of 494 characters (∼4.0%) in the ITS and 2 of 251 (∼1.0%) in the actin sequences. For pathogenicity tests, three seedlings of E. japonicus were used. The leaves for each tree were treated with 10 ml of a conidial suspension by spraying (1x10⁶ conidia ml-1 of the isolate, CDH059), while the three seedlings were treated with distilled water as control. After sprayed, the treated areas were sealed with plastic bags for a day to maintain humidity. Anthracnose symptoms identical to those observed in the field appeared seven days after inoculations, while no symptoms were observed in the control. Re-isolations were successfully achieved from the treatments, fulfilling Koch's postulates. Anthracnose associated with the provisionally novel species of Colletotrichum sp. on E. japonicus has not been recorded elsewhere, and in this regard, this is the first report of anthracnose caused by Colletotrichum sp. on E. japonicus in Korea. To effectively control the disease, more attention should be paid to the host range of the pathogen and other regions where the disease caused by the pathogen might occur in the country.

First Report of Anthracnose Caused by Colletotrichum siamense on Machilus thunbergii Siebold & Zucc. in South Korea

Machilus thunbergii Siebold & Zucc., known as Japanese bay tree, is an evergreen tree distributed widely in East Asia, including South Korea, where the species is of ecological importance. Machilus thunbergii provides habitat for wildlife species and is a common urban tree. In September 2022, anthracnose symptoms on leaves were observed in Jeju (33°26'02.4"N, 126°19'48.8"E) and Tongyeong (34°49'27.1"N, 128°24'01.8"E) in South Korea. Disease incidence on leaves of each affected tree, naturally growing in an urban forest area covering approximately 0.5 ha was approximately ~ 70 % in each study area. Anthracnose symptoms that were observed on 70 to 80% leaves per tree in each study area included orbicular or irregular, whitish-grey spots on leaves that were 1.5 to 3.0 cm in diam. In some cases where leaves were severely affected, larger blotches were formed, leading to bleaching symptoms and eventually defoliation. For pathogen isolation, two or three leaves showing anthracnose symptoms from each of the 15 trees were randomly selected and brought to the laboratory. Fungal isolations were then directly made by transferring spores from acervuli that developed on diseased leaves onto potato dextrose agar (PDA) media. Cushion shaped acervuli filled with salmon to orange-colored conidial masses were produced on media approximately two weeks after the incubation at 25 ± 1°C with a photoperiod of 12 h. Conidia were single celled, hyaline, cylindrical with rounded ends, smooth walls, 13.7 to 18.1 μm long and 3.1 to 4.5 μm wide (n=30). Among 15 cultures that were successfully isolated, 10 isolates were retained based on culture characteristics, and two randomly selected monoconidial cultures were deposited in the culture collection (CDH) of the Chungnam National University, Republic of Korea (Accession No. CDH057-58). Two isolates selected, CDH057 and CDH058, were subjected to identification, and this was achieved based on multiplesequence comparisons using on internal transcribed spacer regions of rDNA (ITS1 and ITS2), partial sequences of actin (ACT) and β-tubulin (TUB2) gene regions amplified using ITS1F / ITS4, ACT-512F / ACT-783R and T1 / Bt2b, respectively (Weir et al. 2012). The representative sequence data were deposited in GenBank under the accession numbers OR473277 and OR473278 for the ITS, OR480772 and OR480773 for ACT, and OR480774 and OR480775 for TUB2. The resulting sequences were further used for a phylogenetic analysis based on the maximum likelihood method using a concatenated dataset of the ITS, ACT and TUB2 gene sequences for Colletotrichum species in the C. gloeosporioides clade. The results showed that the pathogen isolated in this study clustered with Colletotrichum siamense (Vouchered specimens: MFLU 090230, COUFPI291, and COUFPI294) (Prihastuti et al. 2009). Sequence comparisons revealed that the isolates obtained in this study differed from the type species of C. siamense (MFLU 090230; FJ972613 for ITS, FJ 907423 for ACT, FJ907438 for TUB2) at 2 of 258 bp (∼0.8%) and 6 of 387 bp (∼1.6%) in the ACT and TUB2 sequences, respectively, while the ITS was identical to the type species. For pathogenicity tests, a total of ten three-year-old seedlings of M. thunbergii were used. The leaves of each tree were sprayed with 5 ml of conidial suspension (105 conidia/ml, isolate CDH057). Three control plants were sprayed with sterile water. After being sprayed, treated areas were sealed with a plastic bag for 24 hours to preserve humidity. Anthracnose symptoms, identical to those observed in the field, appeared five to seven days after the inoculations, while no symptoms were observed on control plants. The isolates used in the pathogenicity test were reisolated from 90% of lesions, and their identity was confirmed based on sequence comparisons, thus fulfilling Koch's postulates. Species of the C. gloeosporioides species complex include important plant pathogens, particularly C. siamense, which cause significant losses of economic and ecological relevance on a wide range of hosts (~ 100 hosts) (Talhinhas and Baroncelli 2021). Although C. fioriniae in the C. acutatum species complex, was found on M. thunbergii in South Korea (Thao et al. 2023), anthracnose associated with C. siamense on M. thunbergii has not been reported in the country. In this regard, this is the first report of anthracnose caused by C. siamense on M. thunbergii in South Korea. To effectively control the disease, more attention should be paid on the host range of the pathogen and other regions where the disease caused by the pathogen might occur in the country.

Local Heating Induced Single-Crystalline Phase Control in Electrochemical Synthesis of Nanomaterials

Development of synthetic strategies selectively yielding single crystals is desired owing to the facet-dependent chemical reactivities. Recent advances in electrochemical materials synthesis yielded nanomaterials that are surfactant-free, however, typically in polycrystalline forms. In this work, an electrochemical synthetic strategy selectively yielding single-crystalline nanoparticles by implementation of surface-selective heating of the working electrode is developed. Single crystals of copper, silver, gold, and platinum are afforded, and the crystallinity verified by electron diffraction and chemical reactivity studies. Notably, Cu (100) surface prepared by electrochemical synthesis yielded high single product selectivity when applied to electrochemical CO2 reduction catalysis.

Multicenter comparison of analytical interferences of 25-OH vitamin D immunoassay and mass spectrometry methods by endogenous interferents and cross-reactivity with 3-epi-25-OH-vitamin D3

Background

Vitamin D (vit-D) deficiency is highly prevalent in the Korean population, highlighting the need for accurate measurements. In this study, the interferences by endogenous and cross-reactive substances were compared between routine vit-D immunoassays and mass spectrometry (MS) methods.

Methods

Two MS methods and 4 immunoassays from different manufacturers (Abbott, Beckman Coulter, Roche, Siemens) were compared. Residual samples that were icteric, lipemic, hemolyzed, high in rheumatoid factor, from myeloma patients, or patients undergoing hemodialysis were collected. Also, 4 levels of National Institute of Standards and Technology (NIST) Standard Reference Material 972a, and 12 samples serially spiked with 3-epi-25-OH-D3 were prepared.

Results

Significant interferences were observed in hemolytic (Roche), icteric (Beckman and Siemens) and lipemic samples (all 4 immunoassays). Level 4 NIST material and 3-epi-25-OH-D3-spiked samples induced significant cross-reactivity, yielding higher total vit-D measurements in non-epimer-separating MS methods, and both the Beckman and Roche immunoassays.

Conclusion

Most observed interferences were consistent with manufacturers' claims, but overall improvement of immunoassay bias limits is required. Awareness of potential interference is important to increase the accuracy of vit-D measurements. Moreover, care is due when interpreting vit-D results of newborns, infants and less commonly, pregnant women, who are known to have physiologically high levels of the highly cross-reactive 3-epi-25-OH-D3.

The complete mitochondrial genome of a wood-decaying fungus Vanderbylia fraxinea (Polyporaceae, Polyporales)

Vanderbylia fraxinea (Bull.) D.A. Reid, 1973 is an important wood-inhabiting fungus that plays a significant role in nutrient recycling in most forest ecosystems. In this study, the complete mitochondrial genome of V. fraxinea was characterized through de novo assembly using Illumina sequencing data and genome annotation. The mitochondrial genome is a circular molecule of 115,473 bp with a GC content of 28.66%. It comprises a total of 62 genes. Among these, 36 are protein-coding genes including 21 free-standing open reading frames (ORFs), 24 transfer RNA genes, and two ribosomal RNA genes. Core gene set commonly found in fungal mitochondrial genomes is also present in this genome, such as the apocytochrome b (cob), three subunits of the cytochrome c oxidase (cox1, cox2, and cox3), seven subunits of the NADH dehydrogenase (nad1, nad2, nad3, nad4, nad4L, nad5, and nad6), and three subunits of the ATP synthase (atp6, atp8, and atp9), as well as ribosomal RNA subunits (rns and rnl) and a set of transfer RNA genes. Phylogenetic analysis of the protein-coding sequences from the mitochondrial genome revealed a close relationship between V. fraxinea and the Ganoderma species within the Polyporaceae family.

The complete mitochondrial genome of Cladosporium anthropophilum (cladosporiaceae, dothideomycetes)

The genus Cladosporium (Cladosporiaceae, Capnodiales) is a large genus of Ascomycota. Although the genus is mostly reported as saprobes from a wide range of substrates with a worldwide distribution, members of this genus comprise infectious agents in animals and plants. Of those, Cladosporium anthropophilum is a common saprophytic fungus and has been found to be a human opportunistic pathogen and plant pathogen. The complete mitochondrial genome of C. anthropophilum is characterized through the de novo assembly of Illumina sequencing data. The mitochondrial genome is a circular molecule of 35,937 bp with 30.23% GC content and has a total of 47 genes including 16 protein-coding genes, 29 transfer RNA genes, and two ribosomal RNA genes. Based on protein-coding sequences of the mitochondrial genome sequence, a phylogenetic tree was constructed to demonstrate the phylogenetic relationship of C. anthropophilum and its related genera.

Clinical Usefulness of Ultraperformance Liquid Chromatography-Tandem Mass Spectrometry Method for Low Serum Testosterone Measurement

Background

Mass spectrometry methods exhibit higher accuracy and lower variability than immunoassays at low testosterone concentrations. We developed and validated an ultraperformance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS) assay for quantifying serum total testosterone.

Methods

We used an ExionLC UPLC (Sciex, Framingham, MA, USA) system and a Sciex Triple Quad 6500+ (Sciex) MS/MS system in electrospray ionization and positive ion modes with multiple reaction monitoring transitions to evaluate precision, accuracy, linearity, lower limit of quantitation (LLOQ), carryover, ion suppression, stability, and reference intervals. For method comparison, we measured serum testosterone concentrations using this method in 40 subjects whose testosterone concentrations ranged from 0.14 to 55.48 nmol/L as determined using the Architect i2000 immunoassay (Abbott Diagnostics, Abbott Park, IL, USA) and in an additional 160 sera with testosterone concentrations <1.67 nmol/L.

Results

The intra- and inter-run precision CVs were <2.81%, and the accuracy bias values were <3.85%, which were all acceptable. The verified linear interval was 0.03-180.84 nmol/L; the LLOQ was 0.03 nmol/L. No significant carryover and ion suppression were observed. The testosterone in serum was stable at 4°C, at -20°C, and after three freeze-thaw cycles. The reference intervals were successfully verified. The correlation was good at testosterone concentrations of 0.14-55.48 nmol/L; however, the Architect assay showed positive percent bias at concentrations <1.67 nmol/L.

Conclusions

The UPLC-MS/MS assay shows acceptable performance, with a lower LLOQ than the immunoassay. This method will enable the quantitation of low testosterone concentrations.

Complete mitochondrial genome sequence of Pulveroboletus ravenelii (Boletales, Basidiomycota)

Pulveroboletus ravenelii, an ectomycorrhizal fungus, has long been used in traditional Chinese medicine and mushroom dyes; however, its mitogenome and phylogenetic relationship with other taxa remain unexplored. Here, we sequenced the mitochondrial genome of P. ravenelii using next-generation sequencing and found that its mitogenome, a circular DNA molecule of 43,528 bp, comprised 15 protein-coding genes, 15 transfer RNA genes, and two ribosomal RNA genes. The mitogenome had a base composition of A (37.52%), C (11.14%), G (12.21%), and T (39.13%) and a GC content of 23.35%. A phylogenetic tree was constructed to determine the phylogenetic relationship of this species with other taxa based on the mitochondrial genome sequence. This study revealed the phylogenetic positions of P. ravenelii and its related genera for the first time.

Mitrula aurea sp. nov., A New Aero-Aquatic Species from the Republic of Korea

The genus Mitrula (Mitrulaceae, Helotiales), as also known as swamp beacons, inhabits submerged, decaying vegetation in standing or decaying needles, twigs, leaves, and shallow water. They play an important role in carbon cycling in some freshwater ecosystems. In the herbarium of the Korea National Arboretum (KH), seven Mitrula specimens were collected during mushroom forays in the period from 2019 to 2021. The Korean collections were found to be macromorphologically closely related to M. paludosa and M. elegans, but micromorphologically they could be distinguished by characteristics of slightly narrower asci and aseptate ascospores. Our molecular phylogenetic analyses of the internal transcribed spacer (ITS) and 28S rDNA regions also revealed that our specimens were related to M. paludosa and M. elegans, but formed a distinct clade. Based on these results, we reported our specimens as new to science and discussed the phylogeny and diversity of Mitrula species.

First Report of Anthracnose on Juglans regia Caused by Colletotrichum siamense in Korea

Walnut (Juglans regia) is one of the main tree crops cultivated for nut production in South Korea with an estimated production of about 1,189 tons per year (Korea Forest Service 2020). In August 2021, anthracnose symptoms, including dark, depressed, irregularly shaped lesions on fruits and leaves of walnut cv. Sinlyeong, were observed at three orchards in Nonsan (36°10'22.5"N 127°06'14.8"E) and Suwon (37°16'04.7"N 126°55'22.3"E and 37°15'10.6"N 126°57'35.6"E). This led to severe yield loss of walnut fruit with a disease incidence of approximately 70 to 80% in each orchard. Three samples, including infected fruits and leaves, were randomly collected per site. Fungal isolates were isolated either from acervuli filled with conidial masses on infected walnut tissues or from plant tissues that were surface-disinfested, followed by plating onto 2% PDA. Colonies were initially white, later became pale brownish to light gray with concentric rings of salmon sporodochia. White to gray aerial mycelia, reaching 65 mm diameter in 5 days, were abundantly produced on PDA at 25 °C. Appressoria were brown, ovoid, and in some cases, clavate, 5.1-8.7 μm in length, and 3.2-5.1 μm in width (n = 50). Conidia were single celled, hyaline, cylindrical with rounded ends and smooth walls, guttulate, 13.6-18.8 µm in length, and 4.4-6.3 µm in width (n = 50). Setae were absent. Three isolates, i.e., one per orchard, were retained and deposited in the culture collection (CDH) of National Institute of Forest Science, Korea (Accession No. CDH052-054). The internal transcribed spacer (ITS) region of rDNA, beta-tubulin (TUB2) and a partial sequence of the actin (ACT) genes were amplified and sequenced for each of the isolates using the pair of primers, ITS1F/ITS4 (Gardes and Bruns 1993; White et al. 1990), T1/Bt2b (ODonnell and Cigelnik 1997; Glass and Donaldson 1995) and ACT-512F/ACT-783R (Carbone and Kohn 1999), respectively. A BLAST search in GenBank revealed that the sequences of ITS (OK631731-733), TUB2 (OK665927-929) and ACT (OK665930-932) showed sequence identities of 98.6 to 99.6% to Colletotrichum siamense sequences (FJ972613, FJ907423, FJ907438). A maximum likelihood tree, based on a combined dataset of ITS, ACT and TUB2 gene sequences for Colletotrichum spp., revealed that the three isolates were clustered with type specimens of C. siamense. To prepare larger quantities of inoculum for the pathogenicity, mycelial plugs bearing acervuli taken from 2% PDA were incubated in a conical flask containing 200 ml of 2% potato dextrose broth at 25°C on a rotary shaker at 150 rpm for two weeks. Spore concentration was adjusted to 1.0 × 104 ml-1 conidia of C. siamense (CDH054). A 10 to 15 ml of spore suspension was then sprayed on each leaf of 12 seedlings of 'Sinlyeong' walnut (three-year-old), while 7 seedlings were treated with sterile distilled water as a control. Each treated seedling was covered by a plastic bag to maintain moisture for one day. Inoculation trials were repeated twice, in August and September 2021. Symptoms identical to those observed in the field developed four to five days after the inoculations from which the inoculated pathogen was successfully re-isolated, fulfilling Koch's postulates. However, no symptoms were observed in the control. To our knowledge, this is the first report of anthracnose on J. regia caused by C. siamense in Korea. This indicates that disease occurrences must be further rigorously surveyed at the nation-wide scale to effectively control the disease in the country.

Correction to: Maximum emergency department overcrowding is correlated with occurrence of unexpected cardiac arrest

An amendment to this paper has been published and can be accessed via the original article.

Maximum emergency department overcrowding is correlated with occurrence of unexpected cardiac arrest

Background

Emergency department overcrowding negatively impacts critically ill patients and could lead to the occurrence of cardiac arrest. However, the association between emergency department crowding and the occurrence of in-hospital cardiac arrest has not been thoroughly investigated. This study aimed to evaluate the correlation between emergency department occupancy rates and the incidence of in-hospital cardiac arrest.

Methods

A single-center, observational, registry-based cohort study was performed including all consecutive adult, non-traumatic in-hospital cardiac arrest patients between January 2014 and June 2017. We used emergency department occupancy rates as a crowding index at the time of presentation of cardiac arrest and at the time of maximum crowding, and the average crowding rate for the duration of emergency department stay for each patient. To calculate incidence rate, we divided the number of arrest cases for each emergency department occupancy period by accumulated time. The primary outcome is the association between the incidence of in-hospital cardiac arrest and emergency department occupancy rates.

Results

During the study period, 629 adult, non-traumatic cardiac arrest patients were enrolled in our registry. Among these, 187 patients experienced in-hospital cardiac arrest. Overall survival discharge rate was 24.6%, and 20.3% of patients showed favorable neurologic outcomes at discharge. Emergency department occupancy rates were positively correlated with in-hospital cardiac arrest occurrence. Moreover, maximum emergency department occupancy in the critical zone had the strongest positive correlation with in-hospital cardiac arrest occurrence (Spearman rank correlation ρ = 1.0, P < .01). Meanwhile, occupancy rates were not associated with the ED mortality.

Conclusion

Maximum emergency department occupancy was strongly associated with in-hospital cardiac arrest occurrence. Adequate monitoring and managing the maximum occupancy rate would be important to reduce unexpected cardiac arrest.

Ceratocystis quercicola sp. nov. from Quercus variabilis in Korea

During a survey of putative fungal pathogens infecting oak trees in the Gangwon Province of the Republic of Korea, a fungus resembling a Ceratocystis sp. was repeatedly isolated from natural wounds on Quercus variabilis. Morphological comparisons and DNA sequence comparisons based on partial β-tubulin and TEF-1α gene regions showed that the fungus resided in a distinct lineage. This novel Ceratocystis species is described here as C. quercicola sp. nov. This is the first novel species of Ceratocystis to be reported from Korea. A pathogenicity test showed that it can cause lesions on inoculated trees but that it had a very low level of aggressiveness. The discovery of this fungus suggests that additional taxa residing in Ceratocystis are likely to be discovered in Korea in the future.

Taxonomy of the Golovinomyces cynoglossi Complex (Erysiphales, Ascomycota) Disentangled by Phylogenetic Analyses and Reassessments of Morphological Traits

The name Golovinomyces cynoglossi s. lat. is traditionally applied to a complex of morphologically similar powdery mildews on hosts of the plant family Boraginaceae. The current species-level taxonomy within this complex is ambiguous due to the lack of phylogenetic examinations. The present study applied phylogenetic methods to clarify the taxonomy of G. cynoglossi s. lat. Phylogenetic analysis of rDNA ITS sequences retrieved from Asian, European and North American specimens revealed that G. cynoglossi s. lat. collections from different hosts involved several species in five clearly separated lineages. Clade I consists primarily of Golovinomyces cynoglossi s. str. on Cynoglossum. Clade III consists of Golovinomyces sequences retrieved from the host genera Symphytum and Pulmonaria. The taxa within clade III are now assigned to G. asperifoliorum comb. nov. Clade V encompasses G. cynoglossi s. lat. on the host genera Bothriospermum, Buglossoides, Echium, Myosotis, and Trigonotis. The taxa within clade V are now assigned to G. asperifolii comb. nov. The species concerned in this study were lecto- and epitypified to stabilize their nomenclature.

A Single-Chip 64-Channel Ultrasound RX-Beamformer Including Analog Front-End and an LUT for Non-Uniform ADC-Sample-Clock Generation

A 64-channel RX digital beamformer was implemented in a single chip for 3-D ultrasound medical imaging using 2-D phased-array transducers. The RX beamformer chip includes 64 analog front-end branches including 64 non-uniform sampling ADCs, a FIFO/Adder, and an on-chip look-up table (LUT). The LUT stores the information on the rising edge timing of the non-uniform ADC sampling clocks. To include the LUT inside the beamformer chip, the LUT size was reduced by around 240 times by approximating an ADC-sample-time profile w.r.t. focal points (FP) along a scanline (SL) for a channel into a piece-wise linear form. The maximum error between the approximated and accurate sample times of ADC is eight times the sample time resolution (Ts) that is 1/32 of the ultrasound signal period in this work. The non-uniform sampling reduces the FIFO size required for digital beamforming by around 20 times. By applying a 9-dot image from Field-II program and 2-D ultrasound phantom images to the fabricated RX beamformer chip, the original images were successfully reconstructed from the measured output. The chip in a 0.13-um CMOS occupies 30.25 [Formula: see text] and consumes 605 mW.

First Report of Powdery Mildew Caused by Podosphaera xanthii on Sechium edule in Korea

Sechium edule (Jacq.) Sw. (Cucurbitaceae, chayote, mirliton) is native to Mexico and Central America. Several trials have recently been conducted to determine the ability of chayote cultivars to grow under the climatic and soil conditions of South Korea. In April 2013, chayote plants were observed showing typical symptoms of powdery mildew in a glasshouse in Jeju City, Korea. Powdery mildew colonies were circular to irregular, forming white patches on both sides of the leaves. As the disease progressed, entire leaves were covered with white mycelium, followed by leaf withering and premature senescence. The same symptoms were also found on chayote plants in a polyethylene-film-covered greenhouse in Iksan City, Korea, in 2014. Voucher specimens were deposited in the Korea University Herbarium (KUS-F27289, F27422, F28186). Hyphae were flexuous to straight, branched, septate, and 5 to 7 μm wide. Appressoria on the mycelium were nipple-shaped or nearly absent. Conidiophores were straight, 150 to 240 × 10 to 12 μm and produced three to seven immature conidia in chains with a crenate outline. Foot-cells of conidiophores were straight, cylindric, and 52 to 85 μm long. Conidia were hyaline, ellipsoid-ovoid to barrel-shaped, measured 27 to 36 × 16 to 23 μm with a length/width ratio of 1.3 to 2.0, and had distinct fibrosin bodies. Simple to forked germ tubes were produced from the lateral position of conidia. No chasmothecia were found. These structures are typical of the powdery mildew Euoidium anamorph of the genus Podosphaera. Dimensions of foot-cells and conidia were within the ranges provided for P. xanthii (Castagne) U. Braun & Shishkoff, and the length/width ratio of conidia, appressorial characteristics, and conidial germination patterns also conformed to the standard description (2). To confirm the identification, the complete internal transcribed spacer (ITS) region of rDNA of isolate KUS-F27289 was amplified with primers ITS1 and ITS4 and sequenced directly. The resulting 473-bp sequence was deposited in GenBank (Accession No. KM657960). A GenBank BLAST search of the Korean isolate showed 99% similarity with P. xanthii isolates from cucurbitaceous hosts (e.g., AB774155 to AB774158, AB040321, JQ340082, etc.). Pathogenicity was confirmed through inoculation tests by gently pressing a diseased leaf onto young leaves of three asymptomatic, potted chayote plants. Three non-inoculated plants were used as controls. Plants were maintained in a greenhouse at 24 to 34°C. Inoculated leaves started to develop symptoms after 5 days, whereas the control plants remained symptomless. The pathogenicity test was carried out twice with similar results. Powdery mildews of chayote caused by Podosphaera species have been reported in Australia, South Africa, Portugal, India, China, and the United States (1,3,4). To our knowledge, this is the first report of powdery mildew caused by P. xanthii on chayote in Korea. Since chayote production was only recently started on a commercial scale in Korea, powdery mildew infections may pose a serious threat to the safe production of this vegetable. References: (1) P. Baiswar et al. Australas. Plant Dis. Notes 3:160, 2008. (2) U. Braun and R. T. A. Cook. Taxonomic Manual of the Erysiphales (Powdery Mildews), CBS Biodiversity Series No. 11. CBS, Utrecht, 2012. (3) D. F. Farr and A. Y. Rossman. Fungal Databases. Syst. Mycol. Microbiol. Lab. Online publication, ARS, USDA, Retrieved October 4, 2014. (4) R. Singh et al. Plant Dis. 93:1348, 2009.

First Report of Powdery Mildew Caused by Erysiphe heraclei on Peucedanum japonicum in Korea

Peucedanum japonicum Thunb., belonging to the family Apiaceae, is distributed in many Asian countries, including Korea. This plant was recently developed as an edible green and is cultivated under organic farming in Korea. In June 2013, plants showing typical symptoms of powdery mildew were found with approximately 50% disease incidence in polyethylene-film-covered greenhouses in Iksan City, Korea. Symptoms first appeared as circular white colonies, which subsequently showed abundant mycelial growth on the leaves, often covering the whole surface. Infected plants were unmarketable mainly due to signs of white fungal growths and reddish discoloration on the leaves. The same symptoms were found on P. japonicum in poly-tunnels in Iksan City and Jinan County of Korea in 2014. Voucher specimens (n = 3) were deposited in the Korea University Herbarium (KUS). Appressoria were lobed, and solitary or in opposite pairs. Conidiophores were cylindrical, 80 to 145 × 8 to 10 μm, and composed of three to four cells. Foot-cells of conidiophores were straight to substraight, cylindrical, and 25 to 63 μm long. Singly produced conidia were oblong-elliptical to oblong, occasionally ovate, 35 to 50 × 13 to 16 μm with a length/width ratio of 2.3:3.1, with angular/rectangular wrinkling of outer walls, and lacked distinct fibrosin bodies. Germ tubes were produced on the perihilar position of conidia. Primary conidia were apically conical, basally truncate, and generally smaller than the secondary conidia. No chasmothecia were found. These structures are typical of the powdery mildew Pseudoidium anamorph of the genus Erysiphe. The specific measurements and morphological characteristics were consistent with those of E. heraclei DC. (2). To confirm the identification, the complete internal transcribed spacer (ITS) region of rDNA from KUS-F27872 was amplified with primers ITS1/ITS4 and sequenced. The resulting 560-bp sequence was deposited in GenBank (Accession No. KM491178). The obtained ITS sequence shared >99% similarity with those of E. heraclei from apiaceous hosts, e.g., Daucus carota (KC480605), Pimpinella affinis (AB104513), and Petroselinum crispum (KF931139). Pathogenicity was confirmed through inoculation by gently dusting conidia onto leaves of five healthy potted plants. Five non-inoculated plants served as controls. Inoculated plants developed symptoms after 6 days, whereas the control plants remained symptomless. The fungus present on the inoculated plants was identical in morphology to those observed in the field. Powdery mildew of P. japonicum caused by E. heraclei has been reported in Japan (4), and numerous reports of E. heraclei on various species of Peucedanum plants have been made in most part of Europe and East Asia (Japan and far eastern Russia) (1,3). However, this is the first report of powdery mildew caused by E. heraclei on P. japonicum in Korea. Occurrence of powdery mildews is a threat to the quality and marketability of this plant, especially in organic farming. References: (1) K. Amano. Host Range and Geographical Distribution of the Powdery Mildew Fungi. Japan Scientific Societies Press, Tokyo, 1986. (2) U. Braun and R. T. A. Cook. Taxonomic Manual of the Erysiphales (Powdery Mildews), CBS Biodiversity Series No.11. CBS, Utrecht, 2012. (3) D. F. Farr and A. Y. Rossman. Fungal Databases, Syst. Mycol. Microbiol. Lab., online publication. ARS, USDA. Retrieved August 18, 2014. (4) S. Tanda and C. Nakashima. J. Agric. Sci., Tokyo Univ. Agric. 47:54, 2002.

First Report of Choanephora Rot Caused by Choanephora cucurbitarum on Hosta plantaginea in Korea

Hosta plantaginea (Lam.) Asch. is an herbaceous perennial plant with ornamental value. In August 2013, water-soaked spots and wet rot were found on flowers of H. plantaginea in a garden bedded out for landscaping in Hongcheon County, Korea. Symptoms initially appeared as water-soaked spots at the tips of flowers. Dark gray spots on flower petals often coalesced and led to rotting of flowers, with abundant sporulation. However, no symptoms were found on the leaves. Approximately 30% of the flowers were affected in the landscape bed. A fungal isolate was obtained by plating surface-disinfested diseased flower tissue on potato dextrose agar (PDA). Fungal colonies covering the plate (diam. 90 mm) in 48 h were white at first, with abundant aerial mycelia, but later turned pale yellow with abundant sporangiola. Sporangiophores bearing sporangiola were aseptate, hyaline, and usually arose from infected tissue. Sporangiola were ellipsoid to ovoid, indehiscent, brown to dark brown, pediculate, 7 to 12 μm wide and 9 to 20 μm high, and showed longitudinal striations at high magnification. Sporangia were few-spored to multispored, pale brown to brown, and 50 to 150 μm. Sporangiospores from sporangia were broadly ellipsoid, brown to pale brown, with hyaline polar appendages, 8 to 10 μm wide and 15 to 22 μm high. Zygospores were not observed. The morphological and cultural characteristics, especially based on shape and striation of sporangiola, were identical with those of Choanephora cucurbitarum (Berk. & Ravenel) Thaxt. (2,3). A representative specimen was deposited in the Korea University Herbarium (KUS-F27540). Genomic DNA was extracted using a DNeasy Plant Mini Kit (Qiagen Inc., Valencia, CA). The primers ITS1/ITS4 and NL1/LR3 were used to amplify the internal transcribed spacer (ITS) region of rDNA and the D1/D2 region of the large subunit (LSU), respectively (4). The PCR products were purified and directly sequenced. The resulting 594-bp ITS and 680-bp D1/D2 sequences were submitted to GenBank (Accession Nos. KM200034 and KM200035). A GenBank BLAST search of the fungal database showed that the sequences of ITS and D1/D2 regions matched those of C. cucurbitrarum (JN943006 and JN939195) with 100% similarity. A pathogenicity test was conducted by spraying three healthy potted plants (2 months old) with a sporangiola suspension (2 × 10⁴ conidia/ml). Another three potted plants of the same age were treated with sterile water and served as controls. The plants were kept in humid chambers for 2 days and placed in a greenhouse (28°C and 60 to 80% RH). After 4 to 5 days, water-soaked spots were evident on the flowers of inoculated plants. No symptoms were observed on control plants. A pathogenicity test was conducted twice with the same results, fulfilling Koch's postulates. C. cucurbitarum has a wide host range but has not been previously reported to cause disease on H. plantaginea (1). To our knowledge, this is the first report of C. cucurbitarum on H. plantaginea globally as well as in Korea. Choanephora rot of flowers is an issue under high-moisture conditions, so allowing for adequate airflow and a dry plant canopy should aid in disease suppression. References: (1) D. F. Farr and A. Y. Rossman. Fungal Databases. Syst. Mycol. Microbiol. Lab. Online publication, ARS, USDA, retrieved July 11, 2014. (2) P. M. Kirk. Mycol. Pap. 152:1, 1984. (3) A. Saroj et al. Plant Dis. 96:293, 2012. (4) G. Walther et al. Persoonia 30:11, 2013.

First Report of Postharvest Rot of Chestnuts Caused by Mucor racemosus f. sphaerosporus in Korea

The Republic of Korea (South Korea) is the second largest chestnut producer in the world. Major cultivars planted in Korea, including cv. Daebo, Hyogo57, and Okkwang, are hybrids of Japanese chestnut (Castanea crenata) and Chinese chestnut (C. mollissima). Because of high perishability, most chestnuts harvested in September and October are preserved in cold rooms (0°C) for marketing. During a survey of postharvest diseases in April to August 2013, chestnut rots were continuously observed in cold rooms located in Buyeo County, Korea. Preliminary studies revealed that the most common agent of rot appeared to be a species of Mucor. When cut open, infected chestnuts showed partial interior discoloration varying from chalky white to dark brown. About 3 to 10% of chestnuts showed symptoms. Hyogo57 seemed to be the most susceptible variety with higher infection rates, up to 30% in some piles. Isolation was done by placing infected tissues on potato dextrose agar. A representative isolate was deposited in the Korean Agricultural Culture Collection (Accession No. KACC47727). Sporangiophores were mostly erect, branched sympodially, and hyaline. Sporangia were globose, pale yellow at first, then grayish brown at maturity. Columellae were obovoid to globose, subhyaline to pale brown, and usually with truncate base and collars. Sporangiospores were globose to irregular, and 4 to 10 μm in diameter. Chlamydospores were cylindrical to globose with oil drops. The fungus was identified as Mucor racemosus f. sphaerosporus (Hagem) Schipper based on the morphological characteristics and growth at low temperature (3). To conduct molecular analyses, genomic DNA was extracted with DNeasy Plant Mini Kits (Qiagen Inc., Valencia, CA). The primers ITS1/ITS4 and NL1/LR3 were used to amplify the internal transcribed spacer (ITS) region of rDNA and the D1/D2 region of the large subunit (4). The resulting 595-bp ITS sequences and 678 bp D1/D2 sequences were deposited in GenBank (Accession Nos. KJ769665 and KF769666). BLAST searches revealed that both the ITS sequences and D1/D2 sequences showed more than 99% similarity with those of M. racemosus f. sphaerosporus, respectively (JN939201 and AJ878775). To perform a pathogenicity test, a suspension of sporangiospores (1 × 10⁵ spores/ml) was sprayed over 10 chestnuts cv. Hyogo57 wounded with a sewing needle and kept in plastic containers (0°C, 100% RH). Another 10 chestnuts wounded with a sewing needle and treated with sterile water served as controls. After 5 days, typical rots appeared on the inoculated chestnuts, whereas no symptoms were observed on controls. Koch's postulates were fulfilled with the re-isolation of M. racemosus from inoculated chestnuts. The pathogenicity test was carried out twice with similar results. M. hiemalis and M. mucedo have been recorded on chestnuts as postharvest pathogens in Switzerland (2) and Chile (1). To our knowledge, this is first report of postharvest rot of chestnut caused by M. racemosus f. sphaerosporus worldwide as well as in Korea. Further studies are necessary for control measures during cold storage of fresh chestnuts. References: (1) D. F. Farr and A. Y. Rossman. Fungal Databases. Syst. Mycol. Microbiol. Lab., online publication, ARS, USDA, Retrieved May 23, 2014. (2) M. Jermini et al. J. Sci. Food Agric. 86:877, 2006. (3) M. A. A. Schipper. Stud. Mycol. 12:1, 1976. (4) G. Walther et al. Persoonia 30:11, 2013.

First Report of Leaf Spot Caused by Phoma dictamnicola on Dictamnus dasycarpus in Korea

Dictamnus dasycarpus Turcz, known as densefruit pittany, is a perennial herbal plant belonging to the Rutaceae. In Oriental medicine, this plant is used for treatment of various ailments (4). Since the white and purple striped flowers and glossy leaves are of aesthetic value, the plant is popular in gardens throughout Korea. In July 2012, a leaf spot was observed on hundreds of D. dasycarpus with nearly 100% incidence in a garden in Gapyeong County, Korea. Lesions on leaves reaching up to 20 mm in diameter were circular to irregular, brown to dark brown, then becoming zonate with age, and finally fading to grayish brown in the center with a reddish brown margin. The disease caused premature defoliation and reduced plant vigor as well as aesthetic value. In June 2014, the same symptoms were found on D. dasycarpus in a nursery in Jinju City, Korea. Representative samples were deposited in the Korea University Herbarium (KUS). Pycnidia on lesions were epiphyllous, immersed or semi-immersed in host tissue, light brown to olive brown, and 90 to 210 μm in diameter. Ostioles were 15 to 30 μm wide and surrounded by a ring of darker cells. Conidia were hyaline, smooth, ellipsoidal to nearly reniform, straight to mildly curved, aseptate or rarely medianly 1-septate with age, 5.5 to 9.6 × 1.8 to 3.6 μm, and contained small oil drops. These characteristics were consistent with the previous descriptions of Phoma dictamnicola Boerema, Gruyter & Noordel. (1,2). A monoconidial isolate was cultured on potato dextrose agar plates and deposited in the Korea Agricultural Culture Collection (Accession No. KACC46948). Morphological identification of the fungus was confirmed by molecular data. Genomic DNA was extracted using a DNeasy Plant Mini Kit (Qiagen Inc., Valencia, CA). The internal transcribed spacer (ITS) region of rDNA was amplified using the ITS1/ITS4 primers and sequenced. The resulting sequence of 505 bp was deposited in GenBank (Accession No. KM047023). A BLAST search showed that the ITS sequence shared >99% similarity with that of P. dictamnicola (GU237877). For the pathogenicity tests, inoculum was prepared by harvesting conidia from 30-day-old cultures of KACC46948 and a conidial suspension (2 × 10⁶ conidia/ml) was sprayed onto leaves of five healthy seedlings. Five seedlings were sprayed with sterile distilled water, serving as controls. The plants were covered with transparent plastic bags for 48 h in a 25°C glasshouse with a 12-h photoperiod. After 10 days, typical leaf spot symptoms started to develop on the leaves of the inoculated plants. The fungus, P. dictamnicola, was re-isolated from those lesions, confirming Koch's postulates. No symptoms were observed on control plants. Previously, Phoma leaf spot on Dictamnus spp. has been reported in the Netherlands and North America (3) and recently in China (1). To our knowledge, this is the first report of leaf spot on D. dasycarpus caused by P. dictamnicola in Korea. Our observations suggest that low humidity with good ventilation as well as removal of infected leaves and plant debris might be main strategies for preventing this disease. References: (1) Q. Bai et al. Plant Dis. 95:771, 2011. (2) G. H. Boerema et al. Phoma Identification Manual: Differentiation of Specific and Infra-Specific Taxa in Culture. CABI Publishing. Wallingford, UK, 2004. (3) D. F. Farr and A. Y. Rossman. Fungal Databases. Syst. Mycol. Microbiol. Lab., Online publication, USDA ARS, Retrieved June 19, 2014. (4) J. L. Yang et al. Planta Med. 77:271, 2011.

First Report of Powdery Mildew Caused by Phyllactinia actinidiae on Hardy Kiwi in Korea

Actinidia arguta (Siebold & Zucc.) Planch. ex Miq., known as hardy kiwi, is a perennial vine native to Japan, Korea, northern China, and Russian Siberia. It produces a small fruit resembling the kiwifruit. The fruits, referred to as hardy kiwifruit, are edible and often sweeter than kiwifruit. Picking of wild hardy kiwifruits in autumn is a popular ecotourism activity in Korea. In 2000, a powdery mildew disease on the abaxial surface of hardy kiwi leaves was found in Korea. Additional findings of the powdery mildew between 2000 and 2013 showed that the disease of hardy kiwi commonly occurs in Korea. The infected leaves were frequently distorted when young, then becoming prematurely chlorotic and defoliated. Chasmothecia were abundantly formed by September. Voucher specimens (n = 21) were deposited in the Korea University Herbarium (KUS). Mycelia were hypophyllous, thinly effuse, initially forming patches, finally covering the whole abaxial leaf surface. Hyphal appressoria were hook-shaped or often branched, and single or opposite in pairs. Conidiophores were erect, cylindrical, 160 to 300 × 5 to 7.5 μm with straight foot-cells (65 to 115 μm long), basal septum elevated up to 15 μm, and produced conidia singly. Conidia were obpyriform to clavate, papillate at the apex, 55 to 75 × 20 to 32 μm, and devoid of fibrosin bodies. Germ tubes were produced at the terminal and lateral positions of conidia. Chasmothecia were blackish brown, depressed globose, and 190 to 250 μm in diameter. Appendages arising around the equatorial zone of chasmothecia were 9 to 15 in number, acicular with a bulbose base, 1 to 1.3 times as long as the chasmothecial diameter, hyaline throughout, and aseptate. Penicillate cells crowded on the upper part of the chasmothecia were ampulliform, numerous, 50 to 87.8 μm long, and 12.5 to 17.5 μm wide. Asci were 13 to 20 in a chasmothecium, olivaceous brown, 60 to 90 × 22.5 to 40 μm, and short stalked. Ascospores were 2 in an ascus, ellipsoid-ovoid, pale olivaceous, and 32.5 to 40 × 16.5 to 20 μm. On the basis of the morphological characteristics, this fungus was identified as Phyllactinia actinidiae (Jacz.) Bunkina (1). To confirm the identification, the complete internal transcribed spacer (ITS) regions of rDNA of three specimens (KUS-F23673, F26240, and F26308) were amplified using primers ITS5/P3 and sequenced (4). The resulting sequences were deposited in GenBank (Accession Nos. KJ703014, KJ703015, and KJ703016). GenBank BLAST search with the three isolates showed >99% similarity with the results for P. actinidiae on hardy kiwi from Japan (AB080489, AB080500, and AB080508). Actinidia-Phyllactinia associations were recorded in China, Japan, Taiwan, Korea, Russia, and Turkey (2,3). However, P. actinidiae on A. arguta was known only from Japan (3). To our knowledge, this is the first record of P. actinidiae on hardy kiwi in Korea. There has been no finding of powdery mildews on commercial varieties of golden kiwi (A. chinensis) and fuzzy kiwi (A. deliciosa) in Korea. Common occurrence of Phyllactinia powdery mildew on hardy kiwi in Korea can be a potential threat to the commercial kiwi industry. References: (1) U. Braun and R. T. A. Cook. Taxonomic Manual of the Erysiphales (Powdery Mildews), CBS Biodiversity Series No.11. CBS, Utrecht, 2012. (2) I. Erper et al. Scand. J. Forest Res. 27:432, 2012. (3) D. F. Farr and A. Y. Rossman. Fungal Databases. Syst. Mycol. Microbiol. Lab., Online publication. ARS, USDA, March 10, 2014. (4) S. Takamatsu et al. Mycol. Res. 113:117, 2009.

First Report of Black Stem Caused by Botryosporium longibrachiatum on Statice in Korea

Perennial statice is widely cultivated worldwide. In Korea, hybrid statice (Limonium latifolium × bellidifolium) is grown as a commercial cut flower crop in polyethylene-film-covered greenhouses. In April 2013, hundreds of hybrid statice plants of the cvs. Yellow Cream and Pinky Cream were found symptomatic of a previously unknown disease, with 10 to 15% incidence in 10 greenhouses of 1,600 m² surveyed in Gochang County, Korea. Affected stems turned dark brown and were usually covered with a fungus resembling the hoar-frost fungus, Botryosporium longibrachiatum (3), especially in a cool and humid environment. Symptoms consisted of stem blackening, as is typical for burley tobacco (1) and sweet basil (2). According to the farmer of the hybrid statice, stems blackened in the winter and spring of January to April when the tunnels were mostly closed, thus reaching 100% relative humidity (RH) every night due to poor ventilation. The fungus had an elongate main axis with lateral fertile branches in acropetal succession. Conidiophores were simple, erect, macronematous, 32 to 79 μm in length, with a terminal cluster of three to five ampullae. Conidiogneous cells were polyblastic. Conidia were ellipsoidal, elliptical-fusiform, hyaline, 7.6 to 9.5 × 3.0 to 4.2 μm. Colonies on potato dextrose agar (PDA) were floccose, non-pigmented, and chalk-white in color. Morphological and cultural characteristics of the fungus were consistent with previous reports of B. longibrachiatum (Oudem.) Maire (2,3). A voucher specimen was deposited in the Korea University Herbarium (KUS). Isolate KUS-F27305 was submitted to the Korean Agricultural Culture Collection (Accession No. KACC47263). Fungal DNA was extracted from isolate KACC47263 with DNeasy Plant Mini Kits. The complete internal transcribed spacer (ITS) region of rDNA was amplified with the primers ITS1/ITS4 and sequenced. The resulting sequence of 604 bp was deposited in GenBank (Accession No. KF372591). A BLAST search in GenBank exhibited ≥99% nucleotide identity with the ITS sequence of B. longibrachiatum (JX666334) from sweet basil in Korea. To confirm pathogenicity, colonized mycelial agar blocks from isolate KACC47263 were transferred individually onto stem apices and leaves of five statice plants of the cv. Yellow Cream. Five control plants were treated similarly with non-colonized agar blocks. The plants were incubated in a humid chamber at 22 ± 2°C with a 12-h photoperiod for 48 h, and then maintained in 100% RH. After 3 to 4 days, necrotic lesions identical to those observed in the original greenhouses, started to develop on the stem and leaves of inoculated plants, leading to blackened stems covered with the hoar-frost fungus after 14 days. B. longibrachiatum was re-isolated from the lesions of inoculated plants, fulfilling Koch's postulates. No symptoms were observed on control plants. The pathogenicity test was repeated with the cv. Pinky Cream with identical results. To our knowledge, this is the first report of B. longibrachiatum infecting perennial statice globally as well as in Korea. We propose the name black stem of statice for this disease, analogous to the disease on basil (2). References: (1) T. R. Anderson and T. W. Welacky. Plant Dis. 67:1158, 1983. (2) J. H. Park et al. Plant Dis. 97:425, 2013. (3) C. V. Subramanian. Hyphomycetes. Indian Council of Agricultural Research, New Delhi, India, 1971.

First Report of Choanephora Blight Caused by Choanephora infundibulifera on Hibiscus rosa-sinensis in Korea

Hibiscus rosa-sinensis L., commonly known as Chinese hibiscus, is an evergreen flowering shrub belonging to the Malvaceae and is widely cultivated throughout Asia including Korea. In August 2013, blight was observed on Chinese hibiscus in a commercial flower nursery in Seoul, Korea. Initial symptoms began as reddish purple spots at the tip of flowers and expanded to encompass entire flowers. Infected lesions appeared water-soaked, reddish brown, and were followed by rapid rotting of infected tissues. Approximately 50% of the plants surveyed were affected. Monosporous sporangiola formed on infected tissue were transferred to potato dextrose agar (PDA). Fungal colonies were obtained that were at first white with abundant aerial mycelium, and then became yellowish with the appearance of sporangiola. Sporangiophores bearing sporangiola were erect to slightly curved, unbranched, and hyaline. Funnel-shaped secondary vesicles formed on the primary vesicles. Sporangiola were indehiscent, ovoid to subglobose, smooth, non-striated, brown to dark brown, 10 to 27.5 × 8.5 to 17 μm, and sometimes germinated in culture. The fungus was identified as Choanephora infundibulifera (Curr.) D.D. Cunn. based on the morphological and cultural characteristics (2). Voucher specimens were housed in the Korea University Herbarium (KUS). An isolate obtained from KUS-F27535 was deposited in the Korean Agricultural Culture Collection (Accession No. KACC47643) and used for a pathogenicity test and molecular analyses. To confirm identity of the fungus, genomic DNA was extracted with DNeasy Plant Mini Kits (Qiagen Inc., Valencia, CA). The internal transcribed spacer (ITS) region of rDNA and the D1/D2 region of the large subunit (LSU) were amplified with the primers ITS1/ITS4 and NL1/LR3, respectively (3), and sequenced. The resulting 635-bp ITS and 680-bp D1/D2 sequences were deposited in GenBank (Accession Nos. KF486539 and KF486538). A GenBank BLAST search revealed that the ITS sequences showed 100% similarity with that of C. infundibulifera (JN943009) and D1/D2 sequences also showed 100% identity with that of C. infundibulifera (JN939193). A sporangiola suspension (2 × 10⁴ cells/ml) was sprayed over three pots of the shrub, kept in a humid chamber for 2 days, and placed in greenhouse (28°C and 80 to 100% RH). Another three potted plants of the same age were sprayed with sterile water and served as controls. After 4 days, typical blossom blight symptoms, identical to the ones observed in the nursery, developed on the inoculated flowers. No symptoms were observed on controls. C. infundibulifera was re-isolated from inoculated plants. Pathogenicity test was conducted twice with the same results, fulfilling Koch's postulates. Choanephora blight caused by C. infundibulifera on H. rosa-sinenesis has been reported in Japan, Myanmar, Nepal, Guinea, and the United States (1). In Korea, there was one record of this fungus on H. syriacus (1). To our knowledge, this is the first report of C. infundibulifera on H. rosa-sinensis in Korea. This pathogen could be a potential threat to the production of this ornamental shrub over a prolonged period of hot and humid weather. References: (1) D. F. Farr and A. Y. Rossman. Fungal Databases. Syst. Mycol. Microbiol. Lab., Online publication, ARS, USDA, Retrieved February 28, 2014. (2) P. M. Kirk. Mycol. Pap. 152:1, 1984. (3) G. Walther et al. Persoonia 30:11, 2013.

First Report of Powdery Mildew Caused by Golovinomyces biocellatus on Agastache rugosa in Korea

Agastache rugosa (Fisch. & C.A. Mey.) Kuntze, known as Korean mint, is an aromatic plant in the Lamiaceae. It is widely distributed in East Asian countries and is used as a Chinese traditional medicine. In Korea, fresh leaves are commonly added to fish soups and stews (3). In November 2008, several dozen Korean mints plants growing outdoors in Gimhae City, Korea, were found to be severely infected with a powdery mildew. The same symptoms had been observed in Korean mint plots in Busan and Miryang cities from 2008 to 2013. Symptoms first appeared as thin white colonies, which subsequently developed into abundant hyphal growth on stems and both sides of the leaves. Severe disease pressure caused withering and senescence of the leaves. Voucher specimens (n = 5) were deposited in the Korea University Herbarium (KUS). Appressoria on the mycelium were nipple-shaped or nearly absent. Conidiophores were 105 to 188 × 10 to 13 μm and produced 2 to 4 immature conidia in chains with a sinuate outline, followed by 2 to 3 cells. Foot-cells of the conidiophores were straight, cylindrical, slightly constricted at the base, and 37 to 58 μm long. Conidia were hyaline, ellipsoid to barrel-shaped, measured 25 to 40 × 15 to 23 μm (length/width ratio = 1.4 to 2.1), lacked distinct fibrosin bodies, and showed reticulate wrinkling of the outer walls. Primary conidia were obconically rounded at the apex and subtruncate at the base. Germ tubes were produced at the perihilar position of conidia. No chasmothecia were observed. The structures described above were typical of the Oidium subgenus Reticuloidium anamorph of the genus Golovinomyces. The measurements and morphological characteristics were compatible with those of G. biocellatus (Ehrenb.) V.P. Heluta (1). To confirm the identification, molecular analysis of the sequence of the internal transcribed spacer (ITS) region of ribosomal DNA (rDNA) of isolate KUS-F27200 was conducted. The complete ITS rDNA sequence was amplified using primers ITS5 and P3 (4). The resulting 514-bp sequence was deposited in GenBank (Accession No. KJ585415). A GenBank BLAST search of the Korean isolate sequence showed >99% similarity with the ITS sequence of many G. biocellatus isolates on plants in the Lamiaceae (e.g., Accession Nos. AB307669, AB769437, and JQ340358). Pathogenicity was confirmed by gently pressing diseased leaf onto leaves of five healthy, potted Korean mint plants. Five non-inoculated plants served as a control treatment. Inoculated plants developed symptoms after 7 days, whereas the control plants remained symptomless. The fungus present on inoculated plants was identical morphologically to that observed on the original diseased plants. The pathogenicity test was repeated with identical results. A powdery mildew on A. rugosa caused by G. biocellatus was reported from Romania (2). To our knowledge, this is the first report of powdery mildew caused by G. biocellatus on A. rugosa in Korea. The plant is mostly grown using organic farming methods with limited chemical control options. Therefore, alternative control measures should be considered. References: (1) U. Braun and R. T. A. Cook. Taxonomic Manual of the Erysiphales (Powdery Mildews), CBS Biodiversity Series No. 11. CBS, Utrecht, 2012. (2) D. F. Farr and A. Y. Rossman. Fungal Databases. Syst. Mycol. Microbiol. Lab., online publication, USDA ARS, retrieved 17 February 2014. (3) T. H. Kim et al. J. Sci. Food Agric. 81:569, 2001. (4) S. Takamatsu et al. Mycol. Res. 113:117, 2009.

First Report of Powdery Mildew Caused by Podosphaera xanthii on Verbena brasiliensis in Korea

Verbena brasiliensis Vell., commonly known as Brazilian verbena, is native to South America and has been introduced into North America, coastal Europe, southern Africa, and Australasia. Though partly cultivated for garden use, it is invasive in riverine areas and also on roadsides, forest margins, pastures, and waste areas (4). In Korea, this plant was first reported in 1998 in Jeju Island and has become widely naturalized by replacing indigenous plants and disrupting native ecosystems in most of southern part of Korea (3). Since 2009, powdery mildew on Brazilian verbena has been consistently found in several locations of Busan City, Korea. Symptoms appeared as circular to irregular white patches, which subsequently showed abundant hyphal growth on both sides of the leaves and on stems. High disease severity caused poor growth of the plants, resulting in premature senescence and reduced flowering. Specimens (n = 5) were deposited in the Korea University Herbarium (KUS). Appressoria on the mycelium were nipple-shaped or nearly absent. Conidiophores were 140 to 190 × 11 to 12.5 μm and produced 2 to 7 immature conidia in chains with a crenate outline. Foot-cells in conidiophores were straight, cylindric, relatively short, 50 to 65 μm long, and constricted at the very base of branching point from the hypha. Conidia were hyaline, ellipsoid to ovate, measured 28 to 38 × 18.5 to 22 μm (length/width ratio of 1.2 to 1.8), and contained distinct fibrosin bodies. Germ tubes were produced from the lateral position of conidia. No chasmothecia were observed. These structures are typical of the powdery mildew Euoidium anamorph of the genus Podosphaera. The morphological characteristics and measurements were consistent with those of P. xanthii (Castagne) U. Braun & Shishkoff (1). To confirm the identity, the complete internal transcribed spacer (ITS) region of rDNA of the isolate KUS-F27220 was amplified with primers ITS1/ITS4, and sequenced. The resulting 477-bp sequence was deposited in GenBank (Accession No. KJ472787). A GenBank BLAST search of this sequence revealed 100% identity with Podosphaera sp. on V. bonariensis and V.× hybrida from Japan (AB462804 and AB040347). The Podosphaera sp. isolates listed above are now placed in P. xanthii (1). Pathogenicity was confirmed through inoculation by gently pressing a diseased leaf onto leaves of three healthy, potted 2-month-old Brazilian verbena plants. Three non-inoculated plants served as controls. Inoculated plants developed signs and symptoms after 6 days, whereas the control plants remained symptomless. The fungus present on the inoculated leaves was identical morphologically to that originally observed on diseased plants. Powdery mildew of Verbena spp. associated with Podosphaera sp. (including Sphaerotheca sp.) has been globally reported, but not on V. brasiliensis (1,2). To our knowledge, this is the first report of powdery mildew disease caused by P. xanthii on V. brasiliensis globally. Our field observations suggest that the powdery mildew could limit expansion of V. brasiliensis in Korea. References: (1) U. Braun and R. T. A. Cook. Taxonomic Manual of the Erysiphales (Powdery Mildews), CBS Biodiversity Series No.11. CBS, Utrecht, 2012. (2) D. F. Farr and A. Y. Rossman. Fungal Databases. Syst. Mycol. Microbiol. Lab., Online publication, ARS, USDA, Retrieved February 18, 2014. (3) C. G. Song and Y. H. Yang. The Naturalized Plants in Jeju Island. Nam-Jeju County, Jeju, Korea, 2005. (4) P. F. Yao. Kew Bull. 45:101, 1990.

First Report of Powdery Mildew Caused by Erysiphe buhrii on Gypsophila paniculata in Korea

Gypsophila paniculata L. (baby's breath, family Caryophyllaceae), native to Central and Eastern Europe, is commonly cultivated as a commercial cut flower crop in greenhouses in Korea. Since 2011, baby's breath cv. Cassiopeia has been observed affected by a powdery mildew with nearly 100% disease incidence at the stage of harvesting in Iksan City. Powdery mildew colonies first appeared as thin white patches on stems and both sides of the leaves. As disease progressed, plants were covered with dense masses of spores, followed by senescence and reduction of quality of cut flowers. A voucher specimen was deposited in the Korea University Herbarium (Accession KUS-F27313). Appressoria were well-developed, multilobed or moderately lobed, and single or opposite in pairs. Conidiophores were straight, 95 to 150 × 7 to 10 μm, and composed of 3 to 4 cells. Foot-cells were cylindric or slightly sinuous at the base and 37 to 53 μm long. Singly produced conidia were cylindrical to oblong-elliptical, 35 to 56 × 12.5 to 18 μm with a length/width ratio of 2.1 to 3.6, devoid of fibrosin bodies, and with angular/rectangular wrinkling of outer walls. Germ tubes were in the perihilar position on conidia, and ended with lobed appressoria. No chasmothecia were found. These structures are typical of the Pseudoidium anamorph of the genus Erysiphe. Specific measurements and host range were consistent with those of E. buhrii U. Braun (2). To confirm identification, the complete internal transcribed spacer (ITS) region of rDNA of isolate KUS-F27313 was amplified with primers ITS1/ITS4, and sequenced directly. The resulting 725-bp sequence was deposited in GenBank (KJ530705). A GenBank BLAST search of the Korean isolate showed 99% similarity with E. buhrii on Acanthophyllum sp. (Caryophyllaceae) from Iran (AB128924). Pathogenicity was confirmed through inoculation by gently dusting conidia onto leaves of five healthy, potted baby's breath cv. Cassiopeia. Five non-inoculated plants served as controls. Inoculated plants were isolated from non-inoculated plants in separate rooms in a greenhouse at 25 ± 2°C. Inoculated plants developed signs and symptoms after 7 days, whereas the control plants remained symptomless. The fungus present on the inoculated plants was identical morphologically to that originally observed on diseased plants. Pathogenicity test was repeated twice. The powdery mildew disease caused by E. buhrii on baby's breath has been recorded in the former Soviet Union (Armenia, Kazakhstan, Ukraine), Romania, Turkey, Iran, Mongolia, and Argentina (1,3). Also, a fungus occurring on baby's breath was recorded as Oidium sp. from Japan (4). To our knowledge, this is the first report of powdery mildew caused by E. buhrii on baby's breath in Korea. Powdery mildew infections pose a serious threat to production of this cut flower crop. References: (1) K. Amano. Host Range and Geographical Distribution of the Powdery Mildew Fungi. Japan Scientific Societies Press, Tokyo, 1986. (2) U. Braun and R. T. A. Cook. Taxonomic Manual of the Erysiphales (Powdery Mildews), CBS Biodiversity Series No. 11. CBS, Utrecht, 2012. (3) D. F. Farr and A. Y. Rossman. Fungal Databases. Syst. Mycol. Microbiol. Lab., Online publication, ARS, USDA, Retrieved February 18, 2014. (4) M. Satou et al. Ann. Phytopathol. Soc. Jpn. 62:541, 1996.

First Report of Powdery Mildew Caused by Golovinomyces artemisiae on Artemisia annua in Korea

Artemisia annua L., known as sweet wormwood or sweet annie, is native to temperate Asia, but is naturalized throughout the world. It produces artemisinin, a potent antimalarial drug that is also effective in treating other parasitic diseases (4). In August 2013, hundreds of plants showing typical symptoms of powdery mildew were found in Seoul (37°36'29.4″ N 127°02'38.3″ E), Korea. Powdery mildew colonies first appeared as thin white patches, which progressed to abundant hyphal growth on both sides of the leaves, stems, and inflorescence. As symptoms continued to develop, the leaves became distorted and turned purplish-gray. Severe infections caused leaf withering and premature senescence. The same symptoms were found on sweet wormwoods in Nonsan (36°09'55.3″ N 127°01'07.1″ E) and Chuncheon (37°52'27.4″ N 127°43'10.0″ E), Korea. Voucher specimens were deposited in the Korea University Herbarium (KUS). Appressoria on the mycelium were nipple-shaped or occasionally lobed. Conidiophores were cylindrical, measured 120 to 230 × 10 to 12.5 μm, and produced 2 to 4 immature conidia in chains with a sinuate outline, followed by 2 to 3 cells. Foot-cells of conidiophores were straight, cylindrical, and 54 to 100 μm long. Conidia were hyaline, ellipsoid to barrel-shaped, measured 30 to 40 × 15 to 20 μm (length/width ratio of 1.5 to 2.1), lacked distinct fibrosin bodies, and showed reticulate wrinkling of the outer walls. Germ tubes were produced on the perihilar position of conidia. Primary conidia were apically rounded, basally subtruncate, and generally smaller than the secondary conidia. No chasmothecia were observed. The structures described above were typical of the powdery mildew Euoidium anamorph of the genus Golovinomyces, and the fungus measurements were similar to those of G. artemisiae (Grev.) V.P. Heluta (3). The complete internal transcribed spacer (ITS) region of rDNA from KUS-F27763 was amplified with primers ITS1/ITS4 and sequenced. The resulting sequence of 624 bp was deposited in GenBank (Accession No. KJ136112). The obtained ITS sequence shared >99% similarity with G. artemisiae on A. princeps and A. montana from Japan (AB077659 and AB077649) and A. argyi from China (KF056818). Pathogenicity was confirmed through inoculation by gently dusting conidia onto leaves of five healthy potted plants. Five non-inoculated plants served as controls. Inoculated plants developed symptoms after 5 days, whereas the control plants remained symptomless. The fungus present on the inoculated plants was identical morphologically to that originally observed on diseased plants. Powdery mildews of A. annua caused by G. artemisiae have been reported in Japan, China, the Russian Far East, and Romania (1,2). To our knowledge, this is the first report of powdery mildew caused by G. artemisiae on A. annua in Korea. Since sweet wormwood production was only recently started on a commercial scale in Korea, powdery mildew infections pose a serious threat to the production of this plant, especially in organic farming where chemical control options are limited. References: (1) K. Amano. Host Range and Geographical Distribution of the Powdery Mildew Fungi. Japan Scientific Societies Press, Tokyo, 1986. (2) U. Braun. The Powdery Mildews (Erysiphales) of Europe. G. Fischer Verlag, Jena, 1995. (3) U. Braun and R. T. A. Cook. Taxonomic Manual of the Erysiphales (Powdery Mildews), CBS Biodiversity Series No.11. CBS, Utrecht, 2012. (4) P. J. Weathers et al. Phytochem. Rev. 10:173, 2011.

First Report of Powdery Mildew Caused by Golovinomyces sonchicola on Ixeris chinensis in Korea

Ixeris chinensis (Thunb.) Nakai, known as Chinese ixeris, is distributed from Siberia to Japan, including Korea, Taiwan, and China. The whole plant has been used in folk medicine in Asia (4). In Korea, the plants of Chinese ixeris have been gathered and used as a wild root vegetable. During summer to autumn of 2011, Chinese ixeris leaves were found to be heavily infected with a powdery mildew in several locations of Korea. Symptoms first appeared as thin white colonies, which subsequently developed into abundant hyphal growth on both sides of the leaves, leading to drying of the leaves. The same symptoms on Chinese ixeris leaves were continuously observed in 2012 and 2013. Voucher specimens (n = 10) were deposited at Korea University Herbarium (KUS). Hyphal appressoria were moderately lobed or nipple-shaped. Conidiophores arose from the lateral part of the hyphae, measured 100 to 270 × 10 to 12.5 μm, and produced 2 to 6 immature conidia in chains with a sinuate outline. Basal parts of foot-cells in conidiophores were curved. Conidia were barrel-shaped to ellipsoid, measured 26 to 36 × 13 to 19 μm (length/width ratio = 1.7 to 2.4), lacked fibrosin bodies, and showed reticulate wrinkling of the outer walls. Primary conidia were ovate with conical-obtuse apex and subtruncate base. Germ tubes were produced on the perihilar position of conidia. Chasmothecia were not observed. The morphological characteristics were typical of the Euoidium type anamorph of the genus Golovinomyces, and the fungus measurements and structures were consistent with those of G. sonchicola U. Braun & R.T.A. Cook (1). To confirm the identification, internal transcribed spacer (ITS) region of rDNA sequences from a representative material (KUS-F26212) was amplified using primers ITS5/P3 and sequenced (3). The resulting 416-bp sequence was deposited in GenBank (Accession No. KF819857). A GenBank BLAST search revealed that the isolate showed >99% sequence similarity with those of G. cichoracearum from Sonchus spp. (e.g., AB453762, AF011296, JQ010848, etc.). G. sonchicola is currently confined to G. cichoracearum s. lat. on Sonchus spp., based on molecular sequence analyses (1). Pathogenicity was confirmed through inoculation by gently pressing a diseased leaf onto leaves of five healthy potted Chinese ixeris. Five non-inoculated plants served as controls. Inoculated plants developed symptoms after 6 days, whereas the controls remained symptomless. The fungus present on the inoculated plants was identical morphologically to that originally observed on diseased plants. Powdery mildew infections of I. chinensis associated with Golovinomyces have been known in China (2). To our knowledge, this is the first report of powdery mildew disease caused by G. sonchicola on I. chinensis in Korea. Farming of Chinese ixeris has recently started on a commercial scale in Korea. Though no statistical data are available, we postulate the cultivation area in Korea to be approximately 200 ha, mostly growing without chemical controls. Occurrence of powdery mildews poses a potential threat to safe production of this vegetable, especially in organic farming. References: (1) U. Braun and R. T. A. Cook. Taxonomic Manual of the Erysiphales (Powdery Mildews), CBS Biodiversity Series No.11. CBS, Utrecht, 2012. (2) F. L. Tai. Bull. Chinese Bot. Sci. 2:16, 1936. (3) S. Takamatsu et al. Mycol. Res. 113:117, 2009. (4) S. J. Zhang et al. J. Nat. Prod. 69:1425, 2006.

First Report of Powdery Mildew Caused by Erysiphe heraclei on Parsley in Korea

Parsley, Petroselinum crispum (Mill.) Nyman, is a minor but important leaf crop in Korea. In June 2010, parsley plants (cv. Paramount) showing typical symptoms of powdery mildew were found with approximately 90% incidence (percentage of plants showing symptoms) in polyethylene-film-covered greenhouses in an organic farm in Icheon County of Korea. Symptoms first appeared as thin white colonies, which subsequently showed abundant growth on the leaves with chlorosis and crinkling. Most diseased plantings were unmarketable and shriveled without being harvested. The damage due to powdery mildew infections on parsley has reappeared in Icheon County and Gangneung City with confirmation of the causal agent made again in 2011 and 2012. Voucher specimens were deposited in the Korea University Herbarium (KUS). Appressoria on the mycelium were multilobed or moderately lobed. Conidiophores were cylindrical, 75 to 125 × 8 to 10 μm, straight in foot-cells, and produced conidia singly, followed by 2 to 3 cells. Conidia were oblong-elliptical to oblong, 32 to 55 × 14 to 20 μm with a length/width ratio of 1.7 to 2.9, lacked fibrosin bodies, and produced germ tubes on the perihilar position, with angular/rectangular wrinkling of the outer walls. First-formed conidia were apically conical, basally subtruncate to rounded, and generally smaller than the secondary conidia. Chasmothecia were not found. These structures are typical of the powdery mildew Pseudoidium anamorph of the genus Erysiphe. The specific measurements and morphological characteristics were consistent with those of E. heraclei DC. (1). To confirm the identity of the causal fungus, the complete ITS region of rDNA from isolate KUS-F25037 was amplified with primers ITS5 and P3 (3) and sequenced directly. The resulting 606-bp sequence was deposited in GenBank (Accession No. KF680162). A GenBank BLAST search of this sequence revealed 100% identity with that of E. heraclei on Anethum graveolens from Korea (JN603995) and >99% similarity with those of E. heraclei on Daucus carota from Mexico (GU252368), Pimpinella affinis from Iran (AB104513), Anthriscus cerefolium from Korea (KF111807), and many other parsley family (Apiaceae) plants. Pathogenicity was verified through inoculation by gently pressing diseased leaves onto leaves of five healthy potted parsley plants. Five non-inoculated plants served as negative controls. Inoculated plants developed symptoms after 7 days, whereas the control plants remained symptomless. The fungus present on the inoculated plants was morphologically identical to that originally observed on diseased plants. Parsley powdery mildew caused by E. heraclei has been known in Europe, North America, Brazil, and Japan (2,4). To our knowledge, this is the first report of powdery mildew infections by E. heraclei on parsley in Korea. Since cultivation of parsley was only recently started on a commercial scale in Korea, powdery mildew infections pose a serious threat to safe production of this herb, especially those grown in organic farming where chemical options are limited. References: (1) U. Braun and R. T. A. Cook. Taxonomic Manual of the Erysiphales (Powdery Mildews), CBS Biodiversity Series No. 11. CBS, Utrecht, 2012. (2) D. F. Farr and A. Y. Rossman. Fungal Databases. Syst. Mycol. Microbiol. Lab., Online publication, ARS, USDA, retrieved September 17, 2013. (3) S. Takamatsu et al. Mycol. Res. 113:117, 2009. (4) Y. Tsuzaki and K. Sogou. Proc. Assoc. Plant Prot. Shikoku 24:47, 1989.

First Report of Powdery Mildew Caused by Erysiphe elevata on Catalpa bignonioides in Korea

Catalpa bignonioides Walter, known as southern catalpa or Indian bean tree, is native to the southeastern United States and are planted as shade trees throughout the world. In August 2009, typical powdery mildew symptoms on several leaves of the plants below 5% disease incidence were observed in a public garden of Hongcheon County of Korea. In 2011 to 2013, hundreds of southern catalpa trees were found heavily damaged by a powdery mildew with 90 to 100% disease incidence in a park of Incheon City of Korea, about 140 km apart from Hongcheon County. Symptoms appeared as circular to irregular white patches, which subsequently showed abundant mycelial growth on both sides of leaves and herbaceous stems. Severe infections caused poor growth and premature loss of leaves, resulting in reduced aesthetic value. Voucher specimens (n = 6) were deposited in the Korea University Herbarium (KUS). Appressoria on the mycelium were well-developed, lobed, and solitary or in opposite pairs. Conidiophores composed of 3 to 4 cells were 70 to 100 × 7.5 to 10 μm, and produced conidia singly. Foot-cells of conidiophores were flexuous or nearly straight, and 20 to 40 μm long. Conidia were oblong to oblong-elliptical, measured 30 to 42 × 13 to 20 μm (n = 30) with a length/width ratio of 1.6 to 2.5, devoid of distinct fibrosin bodies, and showed angular/rectangular wrinkling of outer walls. Primary conidia were apically rounded, basally subtruncate, and generally smaller than the secondary conidia. Germ tubes were produced on the end of conidia. Chasmothecia were not observed. These structures are typical of the Pseudoidium anamorph of the genus Erysiphe. The specific measurements and characteristics were compatible with those of E. elevata (Burrill) U. Braun & S. Takam. (1,2). To confirm the identification, the complete internal transcribed spacer (ITS) region of rDNA from KUS-F27676 was amplified with primers ITS5 and P3 (4) and sequenced directly. The resulting 675-bp sequence was deposited in GenBank (Accession No. KF840721). A GenBank BLAST search of the ITS sequence showed >99% similarity with isolates of E. elevata on C. bignonioides (Accession Nos. AY587012 to AY587014). Pathogenicity was confirmed through inoculation by gently dusting conidia onto leaves of five healthy southern catalpa seedlings. Five non-inoculated plants served as controls. Inoculated and non-inoculated plants were maintained in a greenhouse at 24 to 28°C in isolation. Inoculated plants developed symptoms after 6 days, whereas the control plants remained symptomless. The fungus present on the inoculated plants was identical morphologically to that originally observed on diseased plants. E.elevata is a North American powdery mildew on Catalpa species which was recently introduced into Europe (1,2,3). To our knowledge, this is the first report of powdery mildew caused by E. elevata on C. bignonioides in Asia as well as in Korea. The disease would be a serious threat to the widespread ornamental plantings of C. bignonioides in Korea. References: (1) N. Ale-Agha et al. Mycol. Prog. 3:291, 2004. (2) U. Braun and R. T. A. Cook. Taxonomic Manual of the Erysiphales (Powdery Mildews), CBS Biodiversity Series No.11. CBS, Utrecht, 2012. (3) D. F. Farr and A. Y. Rossman. Fungal Databases, Syst. Mycol. Microbiol. Lab., Online publication. ARS, USDA. Retrieved November 4, 2013. (4) S. Takamatsu et al. Mycol. Res. 113:117, 2009.

First Report of Powdery Mildew Caused by Cystotheca wrightii on Quercus glauca in Korea

Quercus glauca Thunb. (syn. Cyclobalanopsis glauca (Thunb.) Oerst.), known as ring-cupped oak or Japanese blue oak, is a dominant tree species commonly found in evergreen forests in East Asia (2). In May 2012, hundreds of Q. glauca were found heavily affected by a powdery mildew in several locations of Jeju Islands, Korea. Symptoms on overwintered leaves appeared as circular to irregular blackish violet to dark brown felt-like growths with numerous chasmothecia on abaxial leaf surfaces. New infections on current-year leaves started in early summer and were characterized by typical white patches with abundant sporulation on abaxial leaf surfaces. In early autumn, with formation of special aerial hyphae and without further sporulation, the patches turned light brown to brown. Formation of chasmothecia was noticed from late autumn. The adaxial leaf surface was free of powdery mildew growths and exhibited yellowing and discoloration. Voucher specimens were deposited in the Korea University Herbarium (KUS). Special aerial hyphae were falcate to curved, aseptate, at first hyaline, later deep brown to purplish brown, thick-walled, and 80 to 140 × 6 to 15 μm. Conidiophores were 175 to 245 × 10 to 12 μm, and produced 2 to 4 immature conidia in chains with a sinuate outline. Foot-cells of conidiophores were cylindrical and 80 to 120 μm long. Conidia were lemon- to barrel-shaped, 26 to 35 × 17 to 24 μm with a length/width ratio of 1.2 to 1.6, and devoid of fibrosin bodies. Primary conidia were apically conical and basally subtruncate. Germ tubes produced in the lateral to perihilar position of conidia were long and slender (3 μm wide). Chasmothecia were scattered or gregarious, partly embedded with special aerial hyphae, dark brown, spherical, 55 to 70 μm in diameter, and contained a single ascus. Chasmothecial peridia consisted of two layers. Exoperidia (outer layer) were composed of dark brown, polygonal cells 10 to 20 μm wide. Endoperidia (inner layer) consisted of hyaline, polygonal cells 10 to 15 μm wide. Appendages were basally attached, mycelioid, rare or few, and pale brown to rusty brown. Asci were short stalked, 55 to 72 × 35 to 46 μm, had a terminal oculus 10 to 20 μm wide, and contained 8 ascospores. Ascospores were oblong-elliptical, 22 to 27 × 10 to 12.5 μm, subhyaline, and contained 1 or 2 oil drops. The specific measurements and characteristics (especially falcate aerial hyphae) were consistent with those of Cystotheca wrightii Berk. & M.A. Curtis (1). Fungal DNA was extracted by the Chelex method. The internal transcribed spacer (ITS) region of rDNA of KUS-F27309 was amplified with primers ITS5/P3 and sequenced directly (4). The resulting 589-bp sequence was deposited in GenBank (Accession No. KF735066). A BLAST search in GenBank showed that the Korean isolate had 100% homology with C. wrightii on Q. glauca from Japan (AB000932). Powdery mildews of Q. glauca associated with C. wrightii have been known in Japan, Taiwan, and China (1,3), but not in Korea. Finding of C. wrightii on Q. glauca could pose a potential threat to other evergreen oak species in southern part of Korea. References: (1) U. Braun and R. T. A. Cook. Taxonomic Manual of the Erysiphales (Powdery Mildews), CBS Biodiversity Series No. 11, CBS, Utrecht, Netherlands, 2012. (2) X. Y. Chen et al. Acta Bot. Sin. 39:149, 1997. (3) D. F. Farr and A. Y. Rossman. Fungal Databases. Syst. Mycol. Microbiol. Lab., Online publication, ARS, USDA, retrieved 21 October, 2013. (4) S. Takamatsu et al. Mycol. Res. 113:117, 2009.

First Report of Powdery Mildew Caused by Podosphaera spiraeae on Japanese Spiraea in China

Japanese spiraea (Spiraea japonica L.f.), belonging to Rosaceae, is widely planted for its ornamental value in China. Since July 2011, powdery mildew infections on leaves and stems of Japanese spiraea have been noticed in some parks and gardens of Chengyang District in Qingdao City, China (GPS coordinates 36°31'04.22″ N, 120°39'41.92″ E). Symptoms first appeared as white spots covered with mycelium on both side of the leaves and young stems. As the disease progressed, abundant mycelial growth covered the whole shoots and caused growth reduction and leaf distortion with or without reddening. A voucher specimen was deposited in the herbarium of Qingdao Agricultural University (Accession No. HMQAU13013). Hyphae were flexuous to straight, branched, septate, 5 to 7 μm wide, and had nipple-shaped appressoria. Conidiophores arising from the upper surface of hyphal cells produced 2 to 5 immature conidia in chains with a crenate outline. Foot-cells of conidiophores were straight, 60 to 125 × 7 to 9 μm, and followed by 1 to 2 shorter cells. Conidia were ellipsoid-ovoid to doliiform, measured 25 to 32 × 12 to 15 μm with a length/width ratio of 1.8 to 2.6, and had distinct fibrosin bodies. Chasmothecia were not found. The structures and measurements were compatible with the anamorphic state of Podosphaera spiraeae (Sawada) U. Braun & S. Takam. as described before (1). The identity of HMQAU13013 was further confirmed by analysis of nucleotide sequences of the internal transcribed spacer (ITS) regions amplified using the primers ITS1/ITS4 (4). The resulting 564-bp sequence was deposited in GenBank (Accession No. KF500426). A GenBank BLAST search of complete ITS sequence showed 100% identity with that of P. spiraeae on S. cantoniensis (AB525940). A pathogenicity test was conducted through inoculation by gently pressing a diseased leaf onto five healthy leaves of a potted Japanese spiraea. Five non-inoculated leaves served as controls. The plants were maintained in a greenhouse at 22°C. Inoculated leaves developed typical symptoms of powdery mildew after 5 days, but the non-inoculated leaves remained symptomless. The fungus presented on the inoculated plant was morphologically identical to that originally observed on diseased plants, fulfilling Koch's postulates. Powdery mildew of S. japonica caused by P. spiraeae has been recorded in Japan, Poland, and Switzerland (2,3). To our knowledge, this is the first report of powdery mildew caused by P. spiraeae on Japanese spiraea in China. References: (1) U. Braun and R. T. A. Cook. Taxonomic Manual of the Erysiphales (Powdery Mildews), CBS Biodiversity Series No.11. CBS, Utrecht, 2012. (2) D. F. Farr and A. Y. Rossman. Fungal Databases, Systematic Mycology and Microbiology Laboratory, ARS, USDA. Retrieved from http://nt.ars-grin.gov/fungaldatabases/ September 10, 2013. (3) T. Kobayashi. Index of Fungi Inhabiting Woody Plants in Japan. Host, Distribution and Literature. Zenkoku-Noson-Kyoiku Kyokai Publishing Co. Ltd., Tokyo, 2007. (4) S. Matsuda and S. Takamatsu. Mol. Phylogenet. Evol. 27:314, 2003.

First Report of Powdery Mildew Caused by Erysiphe cruciferarum on Chinese Cabbage in China

Chinese cabbage, Brassica rapa ssp. pekinensis (syn. Brassica pekinensis (Lour.) Rupr.), in the Brassicaceae, is an important vegetable grown on about 3 million ha in China. Since 2012, a powdery mildew has been found infecting Chinese cabbage plants (cv. Qingyanchunbai No. 1) after bolting for seed production from autumn through spring 2013 in a greenhouse in Qingdao, China. Symptoms first appeared as circular to irregular white patches on both sides of the leaves, and on stems and pods, often thinly covering the whole surface. A voucher specimen was deposited in the herbarium of Qingdao Agricultural University (Accession No. HMQAU12216). Hyphae were thin-walled, smooth, hyaline, and 4 to 6 μm wide. Appressoria on the mycelia were well developed, lobed, solitary, or in pairs. Conidiophores were erect, cylindrical, 45 to 110 μm long, and comprised 3 to 4 cells. Foot-cells of conidiophores were straight, cylindrical, 16 to 28 μm long, and 7.6 to 10 μm wide. Singly-produced conidia were oblong to cylindrical or somewhat ellipsoid-doliiform, 32 to 56 × 12 to 18 μm, with a length/width ratio of 1.8 to 3.8, with angular/rectangular wrinkling of the outer wall surface, and lacked distinct fibrosin bodies. Germ tubes were produced in the perihilar position of conidia. No chasmothecia were found. These structures are typical of the powdery mildew Pseudoidium anamorph of Erysiphe (2). The specific measurements and characteristics (especially short foot-cells of conidiophores) were consistent with previous records of Erysiphe cruciferarum Opiz ex L. Junell (2,3). To confirm the identification, the complete internal transcribed spacer (ITS) region of rDNA of isolate HMQAU12216 was amplified (4) and sequenced directly. The resulting 649-bp sequence was deposited in GenBank (Accession No. KC878683). A GenBank BLAST search of ITS sequences showed an exact match with those of E. cruciferarum on B. oleracea var. acephala (GU721075) and Oidium sp. on B. pekinensis (AB522714). A pathogenicity test was conducted by gently pressing a symptomatic leaf loaded with conidia onto a leaf of each five, healthy, potted, 40-day-old plants (cv. Qingyanchunbai No. 1). Five non-inoculated plants served as a control treatment. Inoculated plants were isolated from non-inoculated plants in separate rooms in a greenhouse at 20 ± 2°C. Inoculated plants developed signs and symptoms after 10 days, whereas the control plants remained symptomless. The fungus present on the inoculated plants was identical morphologically to that originally observed on diseased plants, thus fulfilling Koch's postulates. Though many Brassica spp. have been known to be infected with E. cruciferarum throughout the world, powdery mildew of Chinese cabbage caused by E. cruciferarum has been reported only in Finland, Germany, and Korea (1,3). To our knowledge, this is the first report of powdery mildew caused by E. cruciferarum on Chinese cabbage in China. Though occurrence of the powdery mildew on Chinese cabbage was noticed in an experimental breeding plot, this finding poses a potential threat to production of this vegetable in China. References: (1) U. Braun. The Powdery Mildews (Erysiphales) of Europe. Gustav Fischer Verlag, Jena, Germany, 1995. (2) U. Braun and R. T. A. Cook. Taxonomic Manual of the Erysiphales (Powdery Mildews), CBS Biodiversity Series No. 11. CBS, Utrecht, 2012. (3) H. J. Jee et al. Plant Pathol. 57:777, 2008. (4) S. Matsuda and S. Takamatsu. Mol. Phylogen. Evol. 27:314, 2003.

First Report of Powdery Mildew Caused by Erysiphe heraclei on Chervil in Korea

Chervil (Anthriscus cerefolium (L.) Hoffm.), belonging to the family Apiaceae, is an aromatic annual herb that is native to the Caucasus. It is widely used as a flavoring agent for culinary purposes. This herb was recently introduced in Korea. In April 2013, plants showing typical symptoms of powdery mildew disease were observed in a polyethylene film-covered greenhouse in Seoul, Korea. White mycelium bearing conidia formed irregular patches on leaves and stems. Mycelial growth was amphigenous. Severe infections caused leaf withering and premature senescence. Voucher specimens were deposited in the Korea University Herbarium (KUS). Hyphae were septate, branched, with moderately lobed appressoria. Conidiophores presented 3 to 4 cells and measured 85 to 148 × 7 to 9 μm. Foot-cells of conidiophores were 37 to 50 μm long. Conidia were produced singly, oblong-elliptical to oblong, measured 30 to 50 × 13 to 18 μm with a length/width ratio of 2.0 to 3.3, lacked conspicuous fibrosin bodies, and with angular/rectangular wrinkling of the outer walls. Germ tubes were produced in the subterminal position of conidia. Chasmothecia were not found. These structures are typical of the powdery mildew Pseudoidium anamorph of the genus Erysiphe. The specific measurements and morphological characteristics were consistent with those of E. heraclei DC. (1). To confirm identity of the causal fungus, the complete internal transcribed spacer (ITS) region of rDNA of KUS-F27279 was amplified with primers ITS5 and P3 (4) and sequenced directly. The resulting 561-bp sequence was deposited in GenBank (Accession No. KF111807). A GenBank BLAST search of this sequence showed >99% similarity with those of many E. heraclei isolates, e.g., Pimpinella affinis (AB104513), Anethum graveolens (JN603995), and Daucus carota (EU371725). Pathogenicity was confirmed through inoculation by gently pressing a diseased leaf onto leaves of five healthy potted chervil plants. Five non-inoculated plants served as a control treatment. Plants were maintained in a greenhouse at 22 ± 2°C. Inoculated plants developed signs and symptoms after 6 days, whereas the control plants remained healthy. The fungus present on the inoculated plants was identical morphologically to that originally observed on diseased plants. Chervil powdery mildews caused by E. heraclei have been reported in Europe (Bulgaria, France, Germany, Hungary, Italy, Romania, Switzerland, and the former Soviet Union) and the United States (2,3). To our knowledge, this is the first report of powdery mildew caused by E. heraclei on chervil in Asia as well as in Korea. The plant is cultivated in commercial farms for its edible leaves in Korea. Occurrence of powdery mildew is a threat to quality and marketability of this herb, especially those grown in organic farming where chemical control options are limited. References: (1) U. Braun and R. T. A. Cook. Taxonomic Manual of the Erysiphales (Powdery Mildews), CBS Biodiversity Series No. 11, CBS, Utrecht, 2012. (2) D. F. Farr and A. Y. Rossman. Fungal Databases, Syst. Mycol. Microbiol. Lab., Online publication. ARS, USDA. Retrieved July 29, 2013. (3) S. T. Koike and G. S. Saenz. Plant Dis. 88:1163, 2004. (4) S. Takamatsu et al. Mycol. Res. 113:117, 2009.

Globotriaosylceramide Induces Lysosomal Degradation of Endothelial K Ca 3.1 in Fabry Disease

Objective—

Globotriaosylceramide (Gb3) induces K Ca 3.1 downregulation in Fabry disease (FD). We investigated whether Gb3 induces K Ca 3.1 endocytosis and degradation.

Approach and Results—

K Ca 3.1, especially plasma membrane–localized K Ca 3.1, was downregulated in both Gb3-treated mouse aortic endothelial cells (MAECs) and human umbilical vein endothelial cells. Gb3-induced K Ca 3.1 downregulation was prevented by lysosomal inhibitors but not by a proteosomal inhibitor. Endoplasmic reticulum stress–inducing agents did not induce K Ca 3.1 downregulation. Gb3 upregulated the protein levels of early endosome antigen 1 and lysosomal-associated membrane protein 2 in MAECs. Compared with MAECs from age-matched wild-type mice, those from aged α-galactosidase A (Gla)-knockout mice, an animal model of FD, showed downregulated K Ca 3.1 expression and upregulated early endosome antigen 1 and lysosomal-associated membrane protein 2 expression. In contrast, no significant difference was found in early endosome antigen 1 and lysosomal-associated membrane protein 2 expression between young Gla-knockout and wild-type MAECs. In aged Gla-knockout MAECs, clathrin was translocated close to the cell border and clathrin knockdown recovered K Ca 3.1 expression. Rab5, an effector of early endosome antigen 1, was upregulated, and Rab5 knockdown restored K Ca 3.1 expression, the current, and endothelium-dependent relaxation.

Conclusions

—Gb3 accelerates the endocytosis and lysosomal degradation of endothelial K Ca 3.1 via a clathrin-dependent process, leading to endothelial dysfunction in FD.

First Report of Leaf Spot Caused by a Phoma sp. on Schisandra chinensis in Korea

Schisandra chinensis (Turcz.) Baill. is a deciduous woody vine native to northern China and the Russian Far East. Its berries have long been used in traditional Asian medicine. In Korea, S. chinensis is one of 10 major medicinal crops and, as of 2011, the production is 6,892 metric tons from 1,749 ha of cultivation area (1). During summer to autumn of 2011 and 2012, leaf spots were observed on S. chinensis (cv. Cheongsun) with disease incidence of 100% in many locations of Jangsu County, Korea. Early symptoms appeared as small, circular, and pale brown spots. Each spot increased in size, became grayish brown and necrotic, and finally developed concentric rings with a definite margin. Some spots coalesced to cover nearly half of the leaves, often becoming torn and giving a shot hole effect. The infected leaf tissue contained blackish pycnidia from which masses of conidia were released in a humid environment. The pycnidia were brown, globose to pyriform, ostiolate, and 45 to 160 μm in diameter. Conidia were hyaline, smooth, oval to ellipsoidal, aseptate or medianly 1-septate, very occasionally 2-septate, slightly constricted at the septa, 4 to 11 × 2.5 to 5 μm, and contained small oil drops. These morphological characteristics were consistent with the generic concept of Phoma (2). Three monoconidial isolates were successfully cultured by diluting conidia mass in sterile water and streaking conidia suspension on potato dextrose agar (PDA). A representative isolate was deposited in the Korean Agricultural Culture Collection (Accession No. KACC47113) and used for pathogenicity test and molecular analysis. Inoculum for a pathogenicity test was prepared by harvesting conidia from 30-day-old cultures (12-h diurnal cycle, 25°C) and a conidial suspension in water (1.1 × 10⁷ conidia/ml) was sprayed onto leaves of three healthy seedlings (cv. Cheongsun). Three seedlings serving as controls were sprayed until runoff with sterile distilled water. The plants were separately covered with plastic bags for 48 h in a glasshouse. After 10 days, typical leaf spot symptoms developed on the leaves inoculated with the fungus. Phoma sp. was re-isolated from those lesions, confirming Koch's postulates. No symptoms were observed on controls. The pathogenicity test was conducted twice. Fungal DNA was extracted, and the complete internal transcribed spacer (ITS) region of rDNA was amplified with the primers ITS1/ITS4 and sequenced directly. The resulting 520-bp sequence was deposited in GenBank (Accession No. KC928322). The sequence showed over 99% similarity with many Phoma species from various substrates, but no exact matches. Phoma leaf spot of S. chinensis was once recorded in Korea without pathogenicity test and culture deposition (3). Phoma glomerata was recorded as a causal fungus of leaf spot disease on S. chinensis in China (4). The Korean isolates differ from P. glomerata in having larger conidia and are separated from it in ITS sequence data. Therefore, we tentatively place the Korean isolates as unidentified Phoma sp. To our knowledge, this is the first confirmed report of leaf spot disease caused by a Phoma sp. in Korea. References: (1) Anonymous. Statistics of Cultivation and Production of Industrial Crops in 2011. Korean Ministry for Food, Agriculture, Forestry and Fisheries. 2012. (2) M. M. Aveskamp et al. Mycologia 101:363, 2009. (3) E. J. Lee et al. Compendium of Medicinal Plant Diseases with Color Plates. Nat. Inst. Agric. Sci., Suwon, Korea. 1991. (4) X. Wang et al. Plant Dis. 96:289, 2012.

First Report of Powdery Mildew Caused by Podosphaera xanthii on Papaya in Korea

In March 2013, papaya (Carica papaya L. cv. Sunrise) plants growing in polyethylene-film-covered greenhouses in Agricultural Research Center for Climate Change located in Jeju City, Korea, were observed severely affected by a powdery mildew. Symptoms appeared as circular to irregular white patches on both sides of the leaves. As the disease progressed, the plants were covered with dense masses of the spores, eventually causing senescence and withering of leaves. Voucher specimens were deposited in the Korea University Herbarium (KUS). Hyphae were flexuous to straight, branched, septate, and 5 to 8 μm wide. Conidiophores were 110 to 250 × 10 to 12.5 μm and produced 2 to 5 immature conidia in chains with a crenate outline followed by 2 to 3 cells. Foot-cells of conidiophores were straight, cylindric, slightly constricted at the basal septum, and 55 to 110 μm long. Conidia were hyaline, ellipsoid-ovoid, measured 22 to 38 × 18 to 21 μm with a length/width ratio of 1.2 to 1.8, and had distinct fibrosin bodies. Chasmothecia were scattered or partly clustered, dark brown, spherical, 80 to 100 μm in diameter, and each contained a single ascus. Appendages were mycelioid, 1- to 5-septate, brown at the base and becoming paler. Asci were sessile, 72 to 87 × 52 to 68 μm, had a terminal oculus of 17 to 23 μm wide, and contained 8 ascospores, each 17 to 23 × 12.5 to 15 μm. The morphological characteristics and measurements were consistent with those of Podosphaera xanthii (Castagne) U. Braun & Shishkoff (1). To confirm the identification, the complete internal transcribed spacer (ITS) region of rDNA of KUS-F27269 was amplified with the primers ITS5/P3 and sequenced (3). The resulting 443 bp sequence was deposited in GenBank (Accession No. KF111806). The Korean isolate showed >99% similarity with those of many P. xanthii isolates including an isolate on papaya from Taiwan (GU358450). Pathogenicity was confirmed through inoculation tests by gently pressing a diseased leaf onto young leaves of three asymptomatic, potted seedlings (cv. Sunrise). Three non-inoculated seedlings were used as control. Inoculated plants were isolated from non-inoculated plants in separate rooms in a greenhouse at 26 to 30°C. Inoculated leaves developed symptoms after 7 days, whereas the control plants remained symptomless. The fungus present on the inoculated leaves was identical morphologically to that observed on the original diseased leaves, fulfilling Koch's postulates. Powdery mildews of papaya caused by Podosphaera species including P. caricae-papayae have been reported in North America, South America, Hawaii, Africa, Ukraine, Australia, New Zealand, the Cook Islands, India, Thailand, Taiwan, and Japan (2,4). P. caricae-papayae is currently reduced to synonymy with P. xanthii (1). To our knowledge, this is the first report of powdery mildew caused by P. xanthii on papaya in Korea. Though papaya is a minor crop in Korea, producing about 300 M/T annually in greenhouses, powdery mildew disease is a threat to safe production of the fruits. References: (1) U. Braun and R. T. A. Cook. Taxonomic Manual of the Erysiphales (Powdery Mildews), CBS Biodiversity Series No. 11, CBS, Utrecht, 2012. (2) D. F. Farr and A. Y. Rossman. Fungal Databases. Syst. Mycol. Microbiol. Lab., Online publication, ARS, USDA, retrieved April 9, 2013. (3) S. Takamatsu et al. Mycol. Res. 113:117, 2009. (4) J. G. Tsay et al. Plant Dis. 95:1188, 2011.

First Report of Powdery Mildew Caused by Golovinomyces magnicellulatus var. magnicellulatus on Physalis alkekengi var. franchetii in China

Physalis alkekengi var. franchetii (Mast.) Makino, known as Chinese lantern, belonging to Solanaceae, is cultivated for its fruits of medicinal value in East Asia (4). Since July 2010, a powdery mildew has been continuously observed on this plant in Shenyang City in northeastern China. More than 90% of the plants in a garden were affected. Symptoms first appeared as circular to irregular white patches, which progressed to abundant mycelial growth on both sides of leaves and young stems. In the middle of August, chasmothecia were formed abundantly, especially on the lower leaf surface. Voucher specimens were deposited in the herbarium of Qingdao Agricultural University (HMQAU10014, 12047, and 12144). Conidiophores produced 2 to 5 conidia in chains with a sinuate outline, followed by 2 to 3 cells. Foot-cells of conidiophores were straight and 46 to 65 × 9 to 11 μm. Conidia were ellipsoid to barrel-shaped, 26 to 32 × 13 to 15.5 μm, lacked distinct fibrosin bodies, and produced germ tubes on the subterminal position. Chasmothecia were amphigenous, also cauligenous, 100 to 140 μm across, and contained 10 to 25 asci. Appendages were mycelioid, 0.5 to 4 times as long as the chasmothecial diameter, and 1- to 3-septate. Asci were short-stalked, 45 to 64 × 26 to 34 μm, and contained two ascospores of 18 to 25 × 12.5 to 15 μm. The internal transcribed spacer (ITS) region of rDNA was amplified (3) and sequenced. The resulting 600-bp sequence was deposited in GenBank (Accession No. KC488260). A GenBank BLAST search of complete ITS sequence showed 100% identity with that of Golovinomyces orontii on P. alkekengi var. franchetii (AB077647 ex Japan) and >99% similarity with those of G. magnicellulatus on Phlox paniculata (AB077621 ex Japan, AF011303 ex the United States, and GU945756 and GU945757 ex Korea). G. orontii is currently confined to the Golovinomyces isolates on Cichorioideae (1). On the basis of the morphological characteristics and ITS sequence data, the fungus was identified as G. magnicellulatus var. magnicellulatus (U. Braun) V.P. Heluta (1). It was already noted that Golovinomyces isolates on Physalis and Phlox are phylogenetically close each other (3). A pathogenicity test was conducted by gently pressing a diseased leaf onto leaves of five healthy Chinese lanterns. Five non-inoculated plants served as controls. Inoculated plants developed symptoms after 8 days, whereas the control plants remained symptomless. The fungus present on the inoculated plants was morphologically identical to that originally observed on diseased plants, fulfilling Koch's postulates. Powdery mildews of Chinese lantern associated with Golovinomyces species have been known in Korea and Japan (2). A Korean material of Golovinomyces sp. on P. alkekengi var. franchetii was identified as G. magnicellulatus var. magnicellulatus based on morphological characteristics and 100% ITS sequence identity with a Chinese isolate (Shin, unpublished data). To our knowledge, this is the first report of powdery mildew caused by G. magnicellulatus var. magnicellulatus on Chinese lantern in China. References: (1) U. Braun and R. T. A. Cook. Taxonomic Manual of the Erysiphales (Powdery Mildews), CBS Biodiversity Series No.11. CBS, Utrecht, 2012. (2) D. F. Farr and A. Y. Rossman. Fungal Databases. Syst. Mycol. Microbiol. Lab., Online publication, ARS, USDA, retrieved March 22, 2013. (3) S. Matsuda and S. Takamatsu. Mol. Phylogen. Evol. 27:314, 2003. (4) Y. Zheng et al. Phytochem. Anal. 23:337, 2012.

First Report of Powdery Mildew Caused by Erysiphe cruciferarum on Indian Mustard (Brassica juncea) in Korea

Indian mustard (Brassica juncea (L.) Czern.) belongs in the Brassicaceae and is widely cultivated in Korea for the edible leaves. In May 2011, Indian mustard plants of cv. Cheong-Kyeoja, growing in polyethylene-film-covered greenhouses in Hwaseong, Korea, were observed to be affected by a powdery mildew. Symptoms appeared as circular to irregular white colonies, which subsequently showed abundant hyphal growth on both leaf surfaces. Severely infected plants were unmarketable due to leaf discoloration, and most were not harvested. Voucher specimens have been deposited in the Korea University Herbarium (KUS). Appressoria on the mycelium were well developed, lobed, solitary, or in opposite pairs. Conidiophores were cylindrical, 70 to 115 × 8 to 10 μm, and composed of 3 to 4 cells. Foot-cells of conidiophores were straight to substraight, cylindrical, and relatively short (20 to 30 μm long). Singly-produced conidia were oblong to cylindrical or oval, 27.5 to 50 × 14 to 17.5 μm with a length/width ratio of 1.8 to 3.6, with angular/rectangular wrinkling of outer walls, and lacked distinct fibrosin bodies. Germ tubes were produced in the perihilar position of conidia. No chasmothecia were found. These structures are typical of the powdery mildew Pseudoidium anamorph of the genus Erysiphe. The specific measurements and characteristics were consistent with previous records of Erysiphe cruciferarum Opiz ex L. Junell (1). To confirm the identification, the complete internal transcribed spacer (ITS) region of rDNA of KUS-F24819 was amplified with primers ITS5 and P3 (4), and sequenced directly. The resulting 462-bp sequence was deposited in GenBank (Accession No. KC862331). A GenBank BLAST search of the ITS sequence showed 100% identity (462/462 bp) with those of isolates of E. cruciferarum from B. oleracea var. acephala, B. rapa, and Arabidopsis thaliana (GU721075, EU140958, and FJ548627, respectively). Pathogenicity was confirmed through inoculation by gently dusting conidia onto leaves of five healthy, potted Indian mustard plants of the cv. Cheong-Kyeoja. Five non-inoculated plants served as a control treatment. Inoculated plants were isolated from non-inoculated plants in separate rooms in a greenhouse at 18 to 24°C. Inoculated plants developed symptoms after 7 days, whereas the control plants remained symptomless. The fungus present on the inoculated plants was identical morphologically to that originally observed on the diseased plants, fulfilling Koch's postulates. There are records of E. cruciferarum infecting B. juncea in Europe (Finland, Romania, Sweden, Switzerland), the former Soviet Union, Australia, South Africa, and Asia (India, Japan, and China) (2,3). To our knowledge, this is the first report of powdery mildew caused by E. cruciferarum on B. juncea in Korea. Occurrence of powdery mildew is a threat to quality and marketability of this crop, especially those grown in organic farming where chemical control options are limited. References: (1) U. Braun and R. T. A. Cook. Taxonomic Manual of the Erysiphales (Powdery Mildews), CBS Biodiversity Series No. 11. CBS, Utrecht, 2012. (2) D. F. Farr and A. Y. Rossman. Fungal Databases, Syst. Mycol. Microbiol. Lab., Online publication. USDA ARS. Retrieved 20 March 2013. (3) P. Kaur et al. Plant Dis. 92:650, 2008. (4) S. Takamatsu et al. Mycol. Res. 113:117, 2009.

First Report of Powdery Mildew Caused by Podosphaera xanthii on the Invasive Weed, Bidens pilosa, in Korea

Bidens pilosa L., known as Spanish needle or cobbler's peg, is a cosmopolitan weed, originating from South America and common in all tropical and subtropical areas of the world. In Korea, this plant was first reported in 1992 (3), and has become naturalized widely by replacing indigenous plants and disrupting native ecosystems. In the autumn of 2012, hundreds of Spanish needles growing around an industrial complex in Milyang in southern Korea were observed to be severely infected with a powdery mildew. Symptoms first appeared as circular to irregular white patches, which subsequently showed abundant hyphal growth on both sides of the leaves, and on young stems and inflorescences. Red-purplish discoloration and crinkling of the leaves were also observed. Appressoria on the mycelium were nipple-shaped or nearly absent. Conidiophores measured 100 to 190 × 11 to 13 μm, and produced 2 to 5 immature conidia in chains with a crenate outline, at the end of 2 to 3 straight cells of the conidiophore. Conidia were hyaline, ellipsoid to barrel-shaped, measured 28 to 42 × 16.5 to 21 μm (length/width ratio of 1.4 to 2.0), and had distinct fibrosin bodies. Dark brown chasmothecia were found partly embedded in the mycelial felt on leaves and stems, were spherical, gregarious to scattered, and 80 to 100 μm in diameter. Each contained a single ascus and had a terminal oculus 17 to 23 μm wide. Asci were sessile, 70 to 90 × 52 to 65 μm, and contained eight ascospores, each 22 to 28 × 16 to 20 μm. The structures and measurements were consistent with those of Podosphaera xanthii (Castagne) U. Braun & Shishkoff (1). Specimens were deposited in the Korea University Herbarium (KUS). To confirm identity of the causal fungus, the complete internal transcribed spacer (ITS) region of rDNA of isolate KUS-F27201 was amplified with primers ITS5 and P3 (4), and sequenced directly. The resulting 476-bp sequence was deposited in GenBank (Accession No. KC484700). A GenBank BLAST search of this sequence revealed >99% similarity with those of many P. xanthii isolates on plants in the Asteraceae. Pathogenicity was confirmed through inoculation by gently pressing diseased leaf onto leaves of five healthy, potted, young Spanish needle plants. Five non-inoculated plants served as a control treatment. Plants were maintained in a greenhouse at 25 ± 2°C. Inoculated plants developed symptoms after 8 days, whereas the control plants remained symptomless. The fungus present on the inoculated plants was identical morphologically to that originally observed on diseased plants, fulfilling Koch's postulates. Powdery mildews of B. pilosa caused by Podosphaera species have been reported in North America, Africa, and Asia (India and China), but not from Korea (2). To our knowledge, this is the first report of powdery mildew caused by P. xanthii on Spanish needles in Korea. The field observations suggest that the powdery mildew could limit expansion of this invasive weed in Korea. References: (1) U. Braun and R. T. A. Cook. Taxonomic Manual of the Erysiphales (Powdery Mildews), CBS Biodiversity Series No. 11. CBS, Utrecht, The Netherlands, 2012. (2) D. F. Farr and A. Y. Rossman. Fungal Databases. Syst. Mycol. Microbiol. Lab., Online publication, USDA ARS, retrieved 28 February 2013. (3) S. H. Park. Colored Illustrations of Naturalized Plants of Korea. Ilchokak Publishers, Seoul, Korea, 1995. (4) S. Takamatsu et al. Mycol. Res. 113:117, 2009.

First Report of Powdery Mildew Caused by Golovinomyces asterum var. solidaginis on Invasive Weed Solidago gigantea in Korea

Solidago gigantea Aiton (syn. S. serotina Aiton), known as giant goldenrod, is native to North America and has been invasive in Europe and Asia. In Korea, this plant was accidentally introduced around the 1960s and has become widely naturalized by replacing indigenous plants and disrupting the native ecosystem (3). In October 2012, hundreds of giant goldenrod plants growing wild in riverine areas and roadsides were found affected by a powdery mildew in Busan, Korea. Voucher specimens were deposited in the Korea University Herbarium (KUS). Symptoms first appeared as circular to irregular white patches, which subsequently showed abundant hyphal growth on both sides of the leaves. Appressoria on the mycelium were nipple-shaped to moderately lobed. Conidiophores measured 120 to 240 × 10 to 12.5 μm, were arising laterally from hyphal mother cells, and produced 2 to 6 immature conidia in chains with a sinuate outline, followed by 2 to 3 cells. Foot-cells in conidiophores were 42 to 70 μm long and characterized by a distinctly curved base. Conidia were hyaline, ellipsoid to ovate, measured 28 to 42 × 17 to 24 μm (length/width ratio = 1.4 to 2.1), contained small oil drops, lacked distinct fibrosin bodies, and produced germ tubes on the subterminal position. No chasmothecia were observed. The morphological characteristics described above were typical of the Euoidium type anamorph of the genus Golovinomyces, and the fungus measurements and structures were consistent with those of G. asterum var. solidaginis U. Braun (1). To confirm the identity of the causal fungus, the complete ITS region of rDNA from isolate KUS-F27219 was amplified with primers ITS5 and P3 (4) and sequenced. The resulting 508-bp sequence was deposited in GenBank (Accession No. KC513763). A GenBank BLAST search of this sequence revealed >99% similarity with the ITS sequences of G. cichoracearum from Australia (GQ183940 ex Solidago sp.) and Japan (AB077625 ex S. altissima L. and AB077627 ex S. virgaurea subsp. asiatica Kitam. ex Hara). The G. cichoracearum isolates on Solidago spp. listed above are now placed in G. asterum var. solidaginis (1). Pathogenicity was confirmed through inoculation by gently pressing diseased leaves onto leaves of five healthy potted giant goldenrods. Five non-inoculated plants served as controls. Plants were maintained in a greenhouse at 24 to 30°C. Inoculated plants developed signs and symptoms after 7 days, whereas the control plants remained symptomless. The fungus present on inoculated plants was morphologically identical to that originally observed, fulfilling Koch's postulates. Association of S. gigantea with Golovinomyces powdery mildews has been known in North America, South America, Europe, New Zealand, Central Asia (Iran, Kazakhstan, and Kyrgyzstan), and Japan (2). To our knowledge, this is the first report of powdery mildew caused by G. asterum var. solidaginis on S. gigantea in Korea. Our field observations suggest that the powdery mildew could be a limiting factor to suppress the expansion of this invasive weed in Korea. References: (1) U. Braun and R. T. A. Cook. Taxonomic Manual of the Erysiphales (Powdery Mildews), CBS Biodiversity Series No.11. CBS, Utrecht, 2012. (2) D. F. Farr and A. Y. Rossman. Fungal Databases. Syst. Mycol. Microbiol. Lab., Online publication, ARS, USDA, retrieved January 22, 2013. (3) S. M. Oh et al. Kor. J. Weed Sci. 22:280, 2002. (4) S. Takamatsu et al. Mycol. Res. 113:117, 2009.

First Report of Oak Anthracnose Caused by Apiognomonia errabunda on Oriental White Oak in Korea

Oriental white oak, Quercus aliena Blume, is native to East Asia including Korea. It is one of the major deciduous tree species in natural forests in Korea. In May 2012, several hundred trees were found to be heavily damaged by a previously unknown leaf disease in a forest near Songjiho Lake in Goseong County of central Korea. Leaf symptoms began as small, water-soaked, pale greenish to grayish lesions, which enlarged to follow the veins or midribs and to be bounded by them, often killing part of the leaf. Leaf distortion and blight resulted in the later stage of disease development. A number of grayish brown to nearly black acervuli were formed on the lesions, especially on the midribs and veins. Acervuli were mostly hypophyllous, intraepidermal, erumpent, circular to ellipsoid in outline, cushion-like, and 70 to 220 μm in diameter. Conidia (n = 30) were elliptical to fusiform-elliptical, occasionally obclavate, aguttulate or guttulate, hyaline, aseptate, and 7.5 to 20 × 5 to 7.5 μm (mean 14.6 × 6.1 μm). These morphological characteristics of the fungus were consistent with the description of conidial state of Apiognomonia errabunda (Roberge ex Desm.) Höhn. (3,4). Voucher specimens were deposited in the Korea University Herbarium (KUS). An isolate obtained from KUS-F26690 was deposited in the Korean Agricultural Culture Collection (Accession No. KACC46842). Fungal DNA was extracted with DNeasy Plant Mini DNA Extraction Kits (Qiagen Inc., Valencia, CA). The complete internal transcribed spacer (ITS) region of rDNA was amplified with the primers ITS1/ITS4 and sequenced. The resulting 549-bp sequence was deposited in GenBank (KC426947). This showed >99% similarity with sequences of A. errabunda (AJ888475 to 888477). For pathogenicity test, inoculum was prepared by harvesting conidia from 4-week-old cultures on potato dextrose agar. A conidial suspension (1 × 10⁶ conidia/ml) was sprayed onto young leaves of three potted seedlings. Three seedlings treated with sterile distilled water served as controls. Plants were covered with plastic bags to maintain 100% relative humidity for 24 h and then kept in a greenhouse (20 to 26°C and 60 to 80% RH). After 26 days, typical leaf spot symptoms, identical to the ones observed in the field, developed on the inoculated leaves. No symptoms were observed on controls. A. errabunda was reisolated from the lesions of inoculated plants, fulfilling Koch's postulates. Oak anthracnose associated with A. errabunda (including A. quercina) has been recorded in Europe and North America (1,4). Oak anthracnose of evergreen Quercus glauca Thunb. (syn. Cyclobalanopsis glauca (Thunb.) Oerst.) associated with A. supraseptata in Japan is not related to this disease (2). To our knowledge, this is the first report of oak anthracnose of Q. aliena globally and also the first finding of A. errabunda in Asia as well as in Korea. This pathogen is known as one of the major forest pathogens in oak stand in Europe and North America (3). Pending further studies, including a risk assessment, A. errabunda may be considered as a potentially new and serious threat in native and planted ranges of Q. aliena in Korea. References: (1) D. F. Farr and A. Y. Rossman. Fungal Databases. Syst. Mycol. Microbiol. Lab., Online publication, ARS, USDA, retrieved February 18, 2013. (2) S. Kaneko and T. Kobayashi. Trans. Mycol. Soc. Japan 25:11, 1984. (3) A. Ragazzi et al. Phytopathol. Mediterr. 46:295, 2007. (4) M. V. Sogonov et al. Mycol. Res. 111:693, 2007.

First Report of Zonate Leaf Spot Caused by Hinomyces moricola on Japanese Hop in Korea

Japanese hop (Humulus japonicus Siebold & Zucc. = H. scandens (Lour.) Merr.), native to East Asia, is an annual, climbing or trailing vine. The vines can spread to cover large areas of open ground or low vegetation, eventually blanketing the land and vegetation. Pollen of H. japonicus is allergenic, and this species is considered as one of the important causes of pollinosis in Korea and China. It is a notorious invasive weed in the United States and also in France, Hungary, and Italy (1). In September 2012, zonate leaf spots were observed on Japanese hops growing in wetlands in Yeongdong County of Korea. A voucher specimen was preserved in the Korea University Herbarium (KUS-F26901). Initial symptoms included grayish-green to grayish-brown spots without border lines. As the lesions enlarged, they coalesced, leading to leaf blight. Sporophores on the leaf lesions were dominantly hypophyllous, rarely epiphyllous, solitary, erect, easily detachable, and as long as 700 μm. The upper portion of the sporophores consisted of a pyramidal head was ventricose, 320 to 520 μm long and 110 to 150 μm wide. The fungus was isolated from leaf lesions and maintained on potato dextrose agar (PDA). Sclerotia were produced on PDA after 4 to 5 weeks at 18°C without light, but conidia were not observed in culture. These morphological and cultural characteristics were consistent with those of Hinomyces moricola (I. Hino) Narumi-Saito & Y. Harada (= Cristulariella moricola (I. Hino) Redhead) (3,4). An isolate was preserved in the Korean Agricultural Culture Collection (Accession No. KACC46955). Genomic DNA was extracted using the DNeasy Plant Mini DNA Extraction Kit (Qiagen Inc., Valencia, CA). The complete internal transcribed spacer (ITS) region of rDNA was amplified with the primers ITS1/ITS4 and sequenced. The resulting sequence of 452 bp was deposited in GenBank (Accession No. KC460209). A BLAST search in GenBank revealed that the sequence showed an exact match with those of C. moricola (JQ036181 ex Acer negundo and JQ036182 ex Glycine max). To determine the pathogenicity of the fungus, according to the procedure of Cho et al. (2), sporophores with the pyramidal head were carefully detached from a lesion on the naturally infected leaf using a needle. Each sporophore was transferred individually onto five places of four detached healthy leaves. The leaves were placed in dew chambers and incubated at 16°C. Symptoms were observed after 2 days on all inoculated leaves. A number of sporophores and immature sclerotia which were morphologically identical to the ones observed in the field were formed on the abaxial surface of the leaf 2 weeks after inoculation. The pathogen was reisolated from lesions on the inoculated leaves, confirming Koch's postulates. No symptoms were observed on the control leaves kept in humid chambers for 2 weeks. H. moricola was known to cause zonate leaf spots and defoliation on a wide range of woody and annual plants (3). To the best of our knowledge, this is the first report of Hinomyces infection on Japanese hops in Korea. References: (1) Anonymous. Humulus japonicus (Cannabaceae): Japanese hop. Eur. Medit. Plant Prot. Org. (EPPO). 2012. (2) S. E. Cho et al. Plant Dis. 96:906, 2012. (3) D. F. Farr and A. Y. Rossman. Fungal Databases. Syst. Mycol. Microbiol. Lab., Online publication, ARS, USDA, Retrieved December 8, 2012. (4) S. A. Redhead. Can. J. Bot. 53:700, 1975.

First Report of Powdery Mildew Caused by Podosphaera xanthii on Hibiscus mutabilis in Korea

Hibiscus mutabilis L., known as cotton rose, is a deciduous shrub native to China. Horticultural varieties of the species are widely planted throughout the world (4). In September 2012, typical powdery mildew symptoms on the cotton rose were observed in a public garden of Jeju City, Korea. Powdery mildew colonies were circular to irregular white patches on both sides of the leaves and also on young stems and sepals. As the disease progressed, white mycelial growth covered the entire shoot portion, causing leaf distortion. In the middle of November, numerous chasmothecia were formed on the lesions. Voucher specimens (n = 4) were deposited in the Korea University Herbarium (KUS). Hyphal appressoria were only swollen part of hyphae or occasionally nipple-shaped. Conidiophores were 140 to 275 × 10 to 11.5 μm and produced 2 to 8 immature conidia in chains with a crenate outline. Foot-cells of conidiophores were straight, 30 to 65 μm long, and cylindric. Conidia were hyaline, ellipsoid-ovoid, and measured 27 to 42 × 17.5 to 21 μm with a length/width ratio of 1.5 to 2.4, and had distinct fibrosin bodies. Chasmothecia were amphigenous, cauligenous, 85 to 110 μm in diameter, and contained one ascus each. Peridium cells of chasmothecia were irregularly polygonal, large, and 15 to 38 μm wide. Appendages were mycelioid, 1- to 6-septate, brown at the base, and becoming paler. Asci were sessile, oval to broadly fusiform, with terminal oculus of 15 to 20 μm wide. Ascospores numbered eight per ascus were ellipsoidal, 19 to 25 × 14 to 16 μm. The morphological characteristics were consistent with previous records of P. xanthii (Castagne) U. Braun & Shishkoff (1). To confirm the identification, the complete internal transcribed spacer (ITS) region of rDNA from isolate KUS-F27134 was amplified with the primers ITS5 and P3 and sequenced (3). The resulting sequence of 477 bp was deposited in GenBank (Accession No. KC460208). The Korean isolate showed >99% similarity with dozens of sequences of P. xanthii ex cucurbitaceous hosts (e.g., JQ912061, JQ409565, HM070403, etc.) as well as Podosphaera sp. ex H. mutabilis from Japan (AB040308). Pathogenicity was confirmed through inoculation tests by gently pressing diseased leaves onto young leaves of three asymptomatic, potted 2-year-old seedlings. Three non-inoculated seedlings were used as controls. Plants were maintained in a greenhouse at 24 to 30°C. Inoculated leaves developed symptoms after 7 days, whereas the control plants remained symptomless. The fungus present on the inoculated leaves was morphologically identical to that observed on the original diseased leaves, fulfilling Koch's postulates. Powdery mildew infections of H. mutabilis associated with P. xanthii (including P. fuliginea in broad sense) have been known in China, Japan, and Taiwan (1,2). To our knowledge, this is the first report of powdery mildew caused by P. xanthii on H. mutabilis in Korea. Since Jeju, the southmost island of Korea, is the only habitat of cotton rose in Korea and is the northmost natural habitat in Asia, powdery mildew is a new threat to the health of wild populations of cotton rose. References: (1) U. Braun and R. T. A. Cook. Taxonomic Manual of the Erysiphales (Powdery Mildews), CBS Biodiversity Series No.11. CBS, Utrecht, 2012. (2) D. F. Farr and A. Y. Rossman. Fungal Databases. Syst. Mycol. Microbiol. Lab., Online publication, ARS, USDA, retrieved January 18, 2013. (3) S. Takamatsu et al. Mycol. Res. 113:117, 2009. (4) D. A. Wise. J. Hered. 64:285, 1973.

First Confirmed Report of Anthracnose Fruit Rot Caused by Colletotrichum gloeosporioides on Common Fig in Korea

Common fig (Ficus carica L.) was introduced into Korea in the 1890s from Japan and planted in residential gardens for home consumption. Commercial cultivation of the tree did not begin until the 1990s (2). In early August 2012, several dozen unripened fig fruits, cv. Banane, were found damaged by fruit rot in an experimental plot of Jeollabuk-do Agricultural Research and Extension Services, Iksan City, South Korea (GPS coordinates 35°56'38.44″ N, 126°59'37.14″ E). Though infections recurred until late September, infection rates were as low as 1 to 5%. Early symptoms appeared as small, slightly sunken, water-soaked, and circular spots. Lesions increased in size, became more depressed, with a darkened central portion. The darkened areas contained blackish acervuli from which masses of salmon-colored conidia were released in moist weather. A semisoft decay resulted, sometimes causing premature fruit drop. No symptoms were found on leaves. Acervuli were circular to ellipsoid, 50 to 400 μm in diameter. Acervular setae were 2- to 3-septate, dark brown at the base, paler toward the apices, acicular, and up to 120 μm long. Conidia (n = 30) were long obclavate to oblong-elliptical, sometimes fusiform-elliptical, guttulate, hyaline, and 16 to 21 × 4 to 6 μm. These characters were consistent with the description of Colletotrichum gloeosporioides (Penz.) Penz. & Sacc. (4). From an isolate (KACC46943, deposited in the Korean Agricultural Culture Collection), fungal DNA was extracted, and the complete internal transcribed spacer (ITS) region of rDNA was amplified with the primers ITS1(5'-TCCGTAGGTGAACCTGCGG-3')/ITS4(5'-TCCTCCGCTTATTGATATGC-3') and sequenced. The resulting 606-bp sequence was deposited in GenBank (KC430919). The sequence showed 100% identity with sequences of C. gloeosporioides (e.g., JX669446, JQ936316, JQ753973). To confirm pathogenicity, inoculum was prepared by harvesting conidia from 3-week-old cultures on potato dextrose agar. A conidial suspension (3 × 10⁵ conidia/ml) was sprayed onto 10 fruits wounded with a fine needle. Ten fruits sprayed with sterile water served as controls. Fruits were placed in moist chambers for 24 h and then kept in plastic containers (25°C and 60 to 80% RH). After 5 days, fruit rot symptoms, identical to those observed in the field, developed on the inoculated fruits, but never on controls. C. gloeosporioides was reisolated from the lesions of inoculated fruits. Anthracnose associated with C. gloeosporioides on common figs has been known from North America, Central America, South America, Australia, New Zealand, South Africa, and Turkey (1). In Korea, anthracnose fruit rot of common figs was recorded in 1928 under the name C. caricae F. Stevens & J.G. Hall, but without fulfillment of Koch's postulates (3). Subsequent to that time, there has been no published finding of the disease in Korea. C. caricae is regarded as synonymous with C. gloeosporioides (4). To our knowledge, this is the first confirmed report of anthracnose fruit rot of common figs caused by C. gloeosporioides in Korea. Anthracnose fruit rot of common figs may cause losses not only for fruit production but also for marketing. References: (1) D. F. Farr and A. Y. Rossman. Fungal Databases. Syst. Mycol. Microbiol. Lab., Online publication, ARS, USDA, Retrieved January 24, 2013. (2) K. C. Ma et al. Res. Plant Dis. 14:107, 2008. (3) K. Nakata and S. Takimoto. Bull. Agric. Exp. Stat. Korea 15:1, 1928. (4) B. S. Weir et al. 2012. Stud. Mycol. 73:115, 2012.

First Report of Powdery Mildew Caused by Erysiphe cruciferarum on Garden Cress in Korea

Garden cress (Lepidium sativum L.), belonging to the family Brassicaceae, is an edible herb with peppery flavor and aroma (2). This plant was recently introduced and is cultivated as an edible green under organic farming in Korea. In September 2012, seedlings showing typical symptoms of powdery mildew were found in greenhouses in Pyeongchang County, Korea. Symptoms first appeared as thin white colonies, which progressed to abundant growth on the leaves and stems. Infected herbs were unmarketable mainly due to signs of senescence and withering of leaves and mostly abandoned without becoming harvested. Two samples of diseased leaves were deposited in the Korea University Herbarium (KUS Accession Nos. F27137 and F27150). Appressoria on the mycelium were well-developed, lobed, and solitary or in opposite pairs. Conidiophores were unbranched, cylindrical, 88 to 120 × 8.5 to 10 μm, and composed of 3 to 4 cells. Foot-cells of conidiophores were straight to sub-straight, cylindric, 22 to 42 μm long, and generally equal to or shorter than the upper cells. Singly produced conidia were oblong to cylindrical or oval, 34 to 52 × 14 to 18 μm with a length/width ratio of 2.2 to 3.3, with angular/rectangular wrinkling of outer walls, and no distinct fibrosin bodies. Germ tubes were produced on the perihilar position of conidia. No chasmothecia were found. These structures are typical of the powdery mildew Pseudoidium anamorph of the genus Erysiphe. The specific measurements match with those of E. cruciferarum Opiz ex L. Junell as previously described (1). To confirm the identification, the complete internal transcribed spacer (ITS) region of rDNA from KUS-F27150 was amplified with primers ITS5 and P3 and directly sequenced (4). The resulting 554-bp sequence was deposited in GenBank (Accession No. KC414675). The amplified ITS sequence shared >99% similarity with the sequences of E. cruciferarum on several brassicaceous hosts (EU140958, FJ548627, and GU721075). Pathogenicity was confirmed through inoculation by gently dusting conidia onto leaves of five healthy potted garden cress plants. Five non-inoculated plants served as controls. Inoculated plants were isolated from non-inoculated plants in separate rooms in a greenhouse at 18 to 24°C. Inoculated plants developed signs and symptoms after 8 days, whereas the control plants remained symptomless. The fungus present on the inoculated plants was morphologically identical to that originally observed on diseased plants, fulfilling Koch's postulates. Previously, the disease was reported in several European countries and southeastern Asia (Lebanon, Israel, Iran, Iraq, India, and China) (3). To our knowledge, this is the first report of powdery mildew caused by E. cruciferarum on garden cress in Korea. Since garden cress production was only recently started on a commercial scale in Korea, powdery mildew infections pose a serious threat to the production of this herb, especially in organic farming where chemical control options are limited. References: (1) U. Braun and R. T. A. Cook. Taxonomic Manual of the Erysiphales (Powdery Mildews), CBS Biodiversity Series No.11. CBS, Utrecht, 2012. (2) S. Choudhary et al. Indian J. Agric. Sci. 80:752, 2010. (3) D. F. Farr and A. Y. Rossman. Fungal Databases, Syst. Mycol. Microbiol. Lab., Online publication. ARS, USDA. Retrieved December 2, 2012. (4) S. Takamatsu et al. Mycol. Res. 113:117, 2009.

Contradictory Effects of Superoxide and Hydrogen Peroxide on KCa3.1 in Human Endothelial Cells

Reactive oxygen species (ROS) are generated in various cells, including vascular smooth muscle and endothelial cells, and regulate ion channel functions. K_Ca3.1 plays an important role in endothelial functions. However, the effects of superoxide and hydrogen peroxide radicals on the expression of this ion channel in the endothelium remain unclear. In this study, we examined the effects of ROS donors on K_Ca3.1 expression and the K⁺ current in primary cultured human umbilical vein endothelial cells (HUVECs). The hydrogen peroxide donor, tert-butyl hydroperoxide (TBHP), upregulated K_Ca3.1 expression, while the superoxide donors, xanthine/xanthine oxidase mixture (X/XO) and lysopho-sphatidylcholine (LPC), downregulated its expression, in a concentration-dependent manner. These ROS donor effects were prevented by antioxidants or superoxide dismustase. Phosphorylated extracellular signal-regulated kinase (pERK) was upregulated by TBHP and downregulated by X/XO. In addition, repressor element-1-silencing transcription factor (REST) was downregulated by TBHP, and upregulated by X/XO. Furthermore, K_Ca3.1 current, which was activated by clamping cells with 1 µM Ca²⁺ and applying the K_Ca3.1 activator 1-ethyl-2-benzimidazolinone, was further augmented by TBHP, and inhibited by X/XO. These effects were prevented by antioxidants. The results suggest that hydrogen peroxide increases K_Ca3.1 expression by upregulating pERK and downregulating REST, and augments the K⁺ current. On the other hand, superoxide reduces K_Ca3.1 expression by downregulating pERK and upregulating REST, and inhibits the K⁺ current. ROS thereby play a key role in both physiological and pathological processes in endothelial cells by regulating K_Ca3.1 and endothelial function.

First Report of Leaf Spot Caused by Corynespora cassiicola on Rose of Sharon in Korea

Rose of Sharon, Hibiscus syriacus L., is a flowering shrub in the family Malvaceae planted as the national flower of South Korea. In September 2012, previously unknown leaf spots with premature defoliation were observed on dozens of Rose of Sharon plants growing in the shaded area in a park of Dongducheon, Korea. The same symptoms were found on Rose of Sharon in several localities of Korea in 2012. The symptoms usually started as small, dark brown to grayish leaf spots, eventually causing leaf yellowing with significant premature defoliation. The diseased leaves retained for a while green color at the margin of the spots. Representative samples (n = 5) were deposited in the Korea University Herbarium (KUS). Conidiophores of the fungus observed microscopically on the leaf spots were erect, brown to dark brown, single or in clusters, amphigenous but mostly hypophyllous, and measured 80 to 400 × 5 to 10 μm. Conidia were borne singly or in short chains, ranging from cylindrical to broadest at the base and tapering apically, straight to slightly curved, pale olivaceous brown, 2 to 16 pseudoseptate, 50 to 260 × 9 to 20 μm, each with a conspicuous thickened hilum. On potato dextrose agar, single-spore cultures of two isolates were identified as Corynespora cassiicola (Berk. & M.A. Curtis) C.T. Wei on the basis of morphological and cultural characteristics (1,2). Two monoconidial isolates were preserved at the Korean Agricultural Culture Collection (KACC46956 and KACC46957). Genomic DNA was extracted using the DNeasy Plant Mini DNA Extraction Kit (Qiagen Inc., Valencia, CA). The complete internal transcribed spacer (ITS) region of rDNA was amplified with the primers ITS1/ITS4 and sequenced. The resulting sequences of 520 bp were deposited in GenBank (Accession Nos. KC193256, KC193257). A BLAST search in GenBank revealed that the sequences showed 100% identity with those of numerous C. cassiicola isolates from diverse substrates. To conduct a pathogenicity test, a conidial suspension (ca. 2 × 10⁴ conidia/ml) was prepared in sterile water by harvesting conidia from 2-week-old cultures of KACC46956, and the suspension was sprayed onto the leaves of three healthy 2-year-old plants. Inoculated plants were kept in humid chambers for the first 48 h and thereafter placed in the glasshouse. After 10 days, typical leaf spot symptoms developed on the leaves of all three inoculated plants. C. cassiicola was reisolated from the lesions, confirming Koch's postulates. Control plants treated with sterile water remained symptomless. C. cassiicola is cosmopolitan with a very wide host range (1,2). Though Corynespora hibisci Goto was recorded to be associated with brown spot disease of H. syriacus in Japan (4), there is no previous record of C. cassiicola on H. syriacus (3). To our knowledge, this is the first report of Corynespora leaf spot on Rose of Sharon in Korea. According to our field observations in Korea, this disease was found in August and September, following a prolonged period of moist weather. Severe infection resulted in leaf yellowing and premature defoliation, reducing tree vigor and detracting the beauty of green leaves. References: (1) L. J. Dixon et al. Phytopathology 99:1015, 2009. (2) M. B. Ellis. Dematiaceous Hyphomycetes. Commonw. Mycol. Inst., Kew, UK, 1971. (3) D. F. Farr and A. Y. Rossman. Fungal Databases. Syst. Mycol. Microbiol. Lab., Online publication, ARS, USDA, Retrieved November 22, 2012. (4) K. Goto. Ann. Phytopathol. Soc. Japan 12:14, 1942.

First Report of Powdery Mildew of Platanus occidentalis Caused by Erysiphe platani in Korea

Platanus occidentalis L., called American sycamore or American plane, is native to North America. The trees are commonly planted throughout the world on the sides of roads and in parks. In June 2012, diseased leaves exhibiting signs of powdery mildew from a park in Daegu City of Korea were sent to Plant Clinic of Seoul National University for diagnosis. Our observations in Daegu City during September and October 2012 showed that nearly 99% of the approximately 1,000 trees surveyed were infected with a powdery mildew. Voucher specimens (n = 6) were deposited at the Korea University Herbarium (KUS). Symptoms were characterized by chlorosis, distortion, or cupping of young leaves. White superficial colonies developed amphigenously on leaves. Hyphae were flexuous to straight, branched, septate, 4 to 7 μm wide, and had lobed appressoria. Conidiophores were 120 to 350 × 5 to 7.5 μm and produced conidia singly. Foot-cells of conidiophores were straight, cylindric, and 115 to 200 μm long. Conidia were hyaline, ellipsoid-ovoid, measured 33 to 47.5 × 17.5 to 29 μm with a length/width ratio of 1.5 to 2.0, lacked distinct fibrosin bodies, and showed reticulate wrinkling of the outer walls. Germ tubes were produced on the subterminal position of conidia. No chasmothecia were observed. The structures and measurements were compatible with those of the anamorphic state of Erysiphe platani (Howe) U. Braun & S. Takam. (1). To confirm the identification, the complete internal transcribed spacer (ITS) region of the rDNA from isolate KUS-F26959 was amplified with nested PCR and sequenced. The resulting sequence of 625 bp was deposited in GenBank (Accession No. JX997805). A GenBank BLAST search of this sequence showed only one base substitution with the four sequences (JQ365940 to JQ365943) of E. platani on Platanus spp. Pathogenicity was confirmed through inoculation tests by gently pressing diseased leaves onto young leaves of three 2-year-old disease-free seedlings. Three non-inoculated plants were used as control. Plants were maintained in a greenhouse at 24 to 30°C. Inoculated leaves developed symptoms after 7 days, whereas the control plants remained symptomless. The fungus present on the inoculated leaves was morphologically identical to that observed on the original diseased leaves, fulfilling Koch's postulates. Since E. platani first was recorded in the United States in 1874, it has been regarded as endemic in North America. From the second half of the 20th century, introduction and expansion of the range of this fungus to South America, South Africa, Australia and New Zealand, Europe, and Asia have been reported (1,2). To our knowledge, this is the first report of E. platani infections of P. occidentalis in Korea. This species was recorded on P.× hispanica from Japan in 1999 (4) and on P. orientalis from China in 2006 (3), suggesting invasive spread of the sycamore powdery mildew in East Asia. Since American sycamores are widely planted in Korea, control measures should be made to prevent further spread of the disease. References: (1) U. Braun and R. T. A. Cook. Taxonomic Manual of the Erysiphales (Powdery Mildews), CBS Biodiversity Series No.11. CBS, Utrecht, 2012. (2) D. F. Farr and A. Y. Rossman. Fungal Databases. Syst. Mycol. Microbiol. Lab., Online publication, ARS, USDA, Retrieved October 22, 2012. (3) C. Liang et al. Plant Pathol. 57:375, 2008. (4) S, Tanda. J. Agric. Sci., Tokyo Univ. Agric. 43:253, 1999.

First Confirmed Report of Powdery Mildew Caused by Podosphaera xanthii on Farfugium japonicum in Korea

Farfugium japonicum (L.) Kitam., known as Japanese silver leaf, is native to Japan, Korea, and Taiwan. It is grown as an ornamental plant for garden plantings and containers not only in East Asia but more recently also in Europe and North America. Since 2003, powdery mildew infections of F. japonicum 'Gigantea' have been consistently found in the southern part of Korea, including the districts of Jeju, Seogwipo, Busan, Wando, and Ulleungdo. Specimens have been deposited in the Korea University Herbarium (KUS). Signs of powdery mildew first appeared as circular to irregular white patches on both sides of the leaves. The infections were usually severe on young leaves and caused malformation and browning. Appressoria on the mycelium were nipple-shaped or nearly absent. Conidiophores, measuring 160 to 280 × 10 to 12.5 μm, were simple and produced 2 to 12 immature conidia in chains, followed by 2 to 3 cells. Foot-cells in conidiophores were relatively short, 50 to 95 μm long, and constricted at the base. Conidia were hyaline, ellipsoid to ovate, 32 to 48 × 17.5 to 25 μm (length/width ratio = 1.4 to 2.3), had distinct fibrosin bodies, and produced germ tubes on the lateral position. No chasmothecia were observed. The morphology and dimentions of reproductive structures were compatible with those of Podosphaera xanthii (Castagne) U. Braun & Shishkoff (1). To confirm the identity of the causal fungus, the complete ITS region of rDNA from isolate KUS-F26469 was amplified with primers ITS5 and P3 (4) and directly sequenced. The resulting sequence of 475 bp was deposited in GenBank (Accession No. KC155426). A GenBank BLAST search of this sequence revealed 100% identity (475/475 bp) with those of many P. fusca isolates on plants in the Aster family plants including Calendula officinalis, Euryops pectinatus, Syneilesis palmata, and F. japonicum from Japan (e.g., AB040346). The P. fusca isolates listed above are now placed in P. xanthii (1). Pathogenicity was confirmed through inoculation by gently pressing diseased leaves onto leaves of three healthy potted plants of the same cultivar. Three non-inoculated plants served as controls. Plants were maintained in a greenhouse at 25 ± 2°C. Inoculated plants developed typical signs and symptoms of powdery mildew after 8 days, whereas the control plants remained symptomless. The fungus present on the inoculated leaves was morphologically identical to that originally observed on diseased plants. Powdery mildew infections of F. japonicum caused by P. fusca (syn. P. fuliginea) have been reported previously in both Japan and Korea (2). In Korea, it was listed simply as a host fungus of Ampelomyces quisqualis, which is hyperparasitic to powdery midlews, without any data on its identity (3). To our knowledge, this is the first confirmed report of powdery mildew caused by P. xanthii on F. japonicum in Korea. References: (1) U. Braun and R. T. A. Cook. Taxonomic Manual of the Erysiphales (Powdery Mildews), CBS Biodiversity Series No.11. CBS, Utrecht, 2012. (2) D. F. Farr and A. Y. Rossman. Fungal Databases. Syst. Mycol. Microbiol. Lab., Online publication, ARS, USDA, Retrieved November 14, 2012. (3) M. J. Park et al. Fungal Biol. 114:235, 2010. (4) S. Takamatsu et al. Mycol. Res. 113:117, 2009.