All that glitters is not Ramularia.

Ramularia is a species-rich genus that harbours plant pathogens responsible for yield losses to many important crops, including barley, sugar beet and strawberry. Species of Ramularia are hyphomycetes with hyaline conidiophores and conidia with distinct, thickened, darkened, refractive conidiogenous loci and conidial hila, and Mycosphaerella sexual morphs. Because of its simple morphology and general lack of DNA data in public databases, several allied genera are frequently confused with Ramularia. In order to improve the delimitation of Ramularia from allied genera and the circumscription of species within the genus Ramularia, a polyphasic approach based on multilocus DNA sequences, morphological and cultural data were used in this study. A total of 420 isolates belonging to Ramularia and allied genera were targeted for the amplification and sequencing of six partial genes. Although Ramularia and Ramulariopsis proved to be monophyletic, Cercosporella and Pseudocercosporella were polyphyletic. Phacellium isolates clustered within the Ramularia clade and the genus is thus tentatively reduced to synonymy under Ramularia. Cercosporella and Pseudocercosporella isolates that were not congeneric with the ex-type strains of the type species of those genera were assigned to existing genera or to the newly introduced genera Teratoramularia and Xenoramularia, respectively. Teratoramularia is a genus with ramularia-like morphology belonging to the Teratosphaeriaceae, and Xenoramularia was introduced to accommodate hyphomycetous species closely related to Zymoseptoria. The genera Apseudocercosporella, Epicoleosporium, Filiella, Fusidiella, Neopseudocercosporella, and Mycosphaerelloides were also newly introduced to accommodate species non-congeneric with their purported types. A total of nine new combinations and 24 new species were introduced in this study.

Development of a genetic marker set to diagnose aspirin-exacerbated respiratory disease in a genome-wide association study.

We developed a genetic marker set of single nucleotide polymorphisms (SNPs) by summing risk scores of 14 SNPs showing a significant association with aspirin-exacerbated respiratory disease (AERD) from our previous 660 W genome-wide association data. The summed scores were higher in the AERD than in the aspirin-tolerant asthma (ATA) group (P=8.58 × 10(-37)), and were correlated with the percent decrease in forced expiratory volume in 1 s after aspirin challenge (r(2)=0.150, P=5.84 × 10(-30)). The area under the curve of the scores for AERD in the receiver operating characteristic curve was 0.821. The best cutoff value of the summed risk scores was 1.01328 (P=1.38 × 10(-32)). The sensitivity and specificity of the best scores were 64.7% and 85.0%, respectively, with 42.1% positive and 93.4% negative predictive values. The summed risk score may be used as a genetic marker with good discriminative power for distinguishing AERD from ATA.

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.

No association between CCL2 gene polymorphisms and risk of inflammatory demyelinating diseases in a Korean population.

Inflammatory demyelinating disease (IDD), which includes multiple sclerosis (MS) and neuromyelitis optica (NMO), affects the central nervous system. Chemokine ligand 2 (CCL2/MCP-1) is considered an important contributor to the development or progression of IDD. However, genetic association studies of Asian populations are lacking. In this study, we investigated a possible association between CCL2 polymorphisms (rs1024611, rs28730833, and rs2857657) and a Korean population (178 IDD patients and 237 healthy controls) using multiple logistic regression models. However, we did not find any association, which was consistent with other studies in Caucasian populations. In conclusion, our results suggest that CCL2 variants may not contribute to the pathogenesis of IDD.

Association of a microRNA-323b polymorphism with the persistence of hepatitis B virus infection by the enhancement of viral replication.

Recent studies have shown that some mammalian microRNAs (miRNAs) play a role in antiviral defence. However, little is known about the role of miRNA-323b in hepatitis B virus (HBV)-host interaction. We explored whether single nucleotide polymorphism (SNP) of miRNA-323b affects HBV replication in a Korean HBV cohort. Genotyping was performed in a total of 1439 subjects composed of 404 spontaneously recovered (SR) subjects as normal controls and 1035 chronic carriers (CC) of HBV who were further classified into 313 patients with chronic hepatitis, 305 patients with liver cirrhosis and 417 patients with hepatocellular carcinoma. To confirm the effect of SNP of miRNA-323b on HBV replication in vitro, HepAD38 cells were transfected with miRNA-323b wild type or miRNA-323b SNP plasmid vectors, and HBV replication was induced for 5 days. HBV DNA was isolated and quantified using real-time PCR. The polymorphism rs56103835C>T in the pre-miRNA region of miRNA-323b revealed significant minor allele frequency (0.273). rs56103835C>T SNP showed significantly affect persistence of HBV in CC group compared with SR group (OR = 1.29, P = 0.009 in a codominant model; OR = 1.29, P = 0.03 in a dominant model; and OR = 1.78, P = 0.03 in a recessive model). In vitro, the total intracellular HBV DNA content was significantly reduced by miRNA-323b wild-type plasmid vector transfection (P = 0.014). The polymorphism of miRNA-323b was significantly associated with persistence of HBV by the enhancement of HBV replication (P = 0.021). Our findings provide a novel perspective on the role SNP of miRNAs in host-virus interactions in HBV infection.

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.

First Report of Leaf Spot Caused by Pseudocercospora pruni-persicicola on Sweet Cherry in Korea.

Sweet cherry, Prunus avium (L.) L., is not much cultivated in Korea, with only 150 ha planted for domestic consumption. In September 2012, a previously unknown leaf spot was observed with nearly 100% incidence on trees (cv. Seneca) planted in a plastic greenhouse in Iksan City of Korea. Interestingly, the same cultivar as well as other cultivars planted outdoors did not show these symptoms. Leaf spots were irregular to subcircular, dark brown with or without a yellow halo, and becoming coalesced to cause leaf blight and premature defoliation. A cercosporoid fungus was consistently associated with disease symptoms. Fungal structures within the lesion developed on both leaf sides but mostly on the upper side. Stromata were well-developed, globular, dark brown, composed of textura angularis-globosa, and 30 to 80 µm in diameter. Conidiophores were densely fasciculate, pale olivaceous to pale brown, subcylindrical, geniculate-sinuous, 8 to 24 × 3 to 4 µm, and aseptate to 2-septate. Conidiogenous loci were inconspicuous, neither thickened nor darkened. Conidia were olivaceous, generally darker than conidiophores, cylindrical to obclavate, almost straight to mildly curved, short obconically truncate at the base, obtuse at the apex, 1- to 10-septate, constricted at the septa, 12 to 86 × 3.5 to 5 µm, guttulate, and had unthickened, not darkened hila. Morphological characteristics of the fungus were consistent with previous descriptions of Pseudocercospora pruni-persicicola (J.M. Yen) J.M. Yen (1,3). A voucher specimen was deposited in the Korea University herbarium (Accession No. KUS-F27264) and a monoconidial isolate was deposited in the Korean Agricultural Culture Collection (Accession No. KACC47019). The complete internal transcribed spacer (ITS) region of rDNA was amplified with the primers ITS1/ITS4 (4) and sequenced. The resulting 505-bp sequence was deposited in GenBank (Accession No. KF670713). A BLAST search in GenBank revealed that the sequence showed >99% similarity with sequences of many Pseudocercospora species, indicating the close phylogenetic relationship of species in this genus. To conduct a pathogenicity test, a conidial suspension (~1 × 104 conidia/ml) was prepared in sterile water by harvesting conidia from 2-week-old cultures on V8 juice agar, and the suspension was sprayed until runoff onto the leaves of five healthy seedlings. Control plants were sprayed with sterile water. The plants were covered with plastic bags to maintain a relative humidity of 100% for 48 h and then transferred to a greenhouse. Necrotic spots appeared on the inoculated leaves 20 days after inoculation, and were identical to the ones observed in the field. P. pruni-persicicola was re-isolated from symptomatic leaf tissues, fulfilling Koch's postulates. Control plants remained symptomless. The fungus has previously been recorded on Prunus persica (L.) Stokes in Taiwan (2,3). To our knowledge, this is the first report of this fungus on P. avium globally as well as in Korea. The disease poses a new threat to the sweet cherry industry in Korea. References: (1) U. Braun and V. A. Melnik. Cercosporoid Fungi from Russia and Adjacent Countries. Rus. Acad. Sci., St.-Petersburg, 1997. (2) D. F. Farr and A. Y. Rossman. Fungal Databases. Syst. Mycol. Microbiol. Lab., Online publication, ARS, USDA, Retrieved August 24, 2013. (3) J. M. Yen. Rev. Mycol. 42:57, 1978. (4) T. J. White et al. PCR Protocols. Academic Press, San Diego, CA, 1990.

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 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 Quinoa Downy Mildew Caused by Peronospora variabilis in Republic of Korea.

Quinoa (Chenopodium quinoa Willd.) has become increasingly popular due to its high nutritional value and adaptability to harsh environments. Several field trials have recently been conducted to determine the ability of quinoa cultivars to grow under climate and soil conditions of Republic of Korea. During July 2013, which is the rainy season, plants showing typical symptoms of downy mildew were first observed in an experimental plot in Iksan City, Korea. Infection resulted in small to large, irregular chlorotic areas on the upper leaf surface with a gray mildew developing on the abaxial surface, and often leading to early defoliation. The same symptoms of downy mildew were also found in Pyeongchang County and Imsil County, Korea. A sample from Iksan City was deposited in the Korea University Herbarium (Accession No. KUS-F27388) and used for microscopy and molecular studies. Microscopic examination revealed colorless conidiophores emerging from stomata, straight to slightly curved, 350 to 550 × 10 to 18 µm, and sub-dichotomously branched in 5 to 7 orders. Ultimate branchlets were mostly in pairs, flexuous to curved, 10 to 30 µm long, and had obtuse tips. Conidia were pale brown to olivaceous, broadly ellipsoidal to ellipsoidal, and 25 to 32 × 22 to 25 µm with a length/width ratio of 1.20 to 1.35. These characteristics fit well with Peronospora variabilis, which was previously recorded to be parasitic to C. quinoa and C. album, although P. farinosa f. sp. chenopodii has often been considered a causal agent of downy mildew on quinoa (1). To confirm this morphological identification, amplification and sequencing of the internal transcribed spacer (ITS) region of the rDNA of the Korean specimen were performed using procedures outlined by Choi et al. (1) with oomycete-specific primers DC6 and LR0. The resulting 796-bp sequence was deposited in GenBank (Accession No. KF887493). A comparison with the ITS sequences available in GenBank revealed that it is identical to P. variabilis found on C. album (EF614959, EF614961), and shows only one base pair substitution with another isolates from C. quinoa (EU113305, EU113306). Therefore, the pathogen found in Korea was confirmed to be P. variabilis. Downy mildew is the most damaging disease of quinoa in Argentina, Bolivia, Colombia, Ecuador, and Peru (1). Increasing reports of this disease from India, Canada, the United States, Portugal, and Denmark (2,3,4) have revealed its worldwide occurrence and spread. To our knowledge, this is the first report of a downy mildew on quinoa in Korea (3). It suggests that quinoa downy mildew poses a new and serious threat to production of this crop in Korea. References: (1) Y. J. Choi et al. Mycopathologia 169:403, 2010. (2) S. Danielson et al. Seed Sci. Technol. 32:91, 2004. (3) D. F. Farr and A. Y. Rossman. Fungal Databases. Syst. Mycol. Microbiol. Lab., Online publication, ARS, USDA, Retrieved November 5, 2013. (4) A. L. Testen et al. Plant Dis. 96:146, 2012.

First Report of White Blister Rust Caused by Albugo candida on Wasabi in Korea.

Wasabi (Wasabia japonica (Miq.) Matsum.), a member of the Brassicaceae family, is a commercially important crop in East Asian countries such as China, Japan, Korea, and Taiwan. In Korea, wasabi is under commercial development since it has become popular as a condiment due to its strong pungent constituents. In May 2013, wasabi plants showing typical symptoms of white blister rust disease were first observed in plastic greenhouses in Taebaek City, Korea. Leaves of infected plants had whitish sori on the lower surfaces and chlorotic blotches on the corresponding upper leaf surfaces. Later, sori changed to creamy to light tan with necrosis of leaf lesion. New infections might occur anytime during the growing season. A representative sample was deposited in the Korea University Herbarium (KUS-F27596). Microscopic examination of fresh materials was performed under a light microscope. The grouped sporangiophores were hyaline, clavate or cylindric, and measured 20 to 35 × 10 to 14 µm. The sporangia were arranged in basipetal chains, hyaline, globose to subglobose, with uniform wall thickness and measured 16 to 21 × 13 to 18 µm. The primary sporangia were morphologically similar to the secondary sporangia, although the former exhibited a slightly thicker wall than the latter. No resting organs were observed. Previously, the white blister rust pathogen on wasabi has been considered either Albugo candida or A. wasabiae, although the latter name is often considered a synonym of A. candida. Based on the morphological characteristics and the specific host plant, the causal agent of this disease was identified as A. candida (2). To confirm this morphological identification, genomic DNA was extracted from infected plant tissue, and the amplification and sequencing of the internal transcribed spacer (ITS) region of rDNA of the Korean specimen were performed using procedures outlined by Choi et al. (1), with oomycete-specific primer set, DC6 and LR0. The resulting 835-bp sequence of the region was deposited in GenBank (Accession No. KF887494). Since this was the first ITS sequence submitted for A. candida on wasabi, comparable data were not available. A comparison with the ITS sequences available in the GenBank database revealed that it is identical to A. candida found on Capsella bursa-pastoris (AF271231), and shows a high similarity of 99% with many A. candida sequences originating from other brassicaceous plants. Therefore, the pathogen found in Korea was confirmed to be A. candida. In Korea, it has been reported that A. candida attacks Brassica juncea, B. campestris subsp. penikensis, and B. napus (3), but to our knowledge this is the first record of A. candida on wasabi (4). The white blister rust caused by A. candida is one of the most devastating diseases of wasabi in Japan and Taiwan where the crop is widely cultivated. On the other hand, in the United States, Canada, and New Zealand, where wasabi is a new crop on a commercial scale, there is no record of this disease. These facts taken together suggest that wasabi white blister rust be not only currently spreading in East Asia, but it also poses a new and serious threat to production of this crop in countries in which it is currently absent. References: (1) Y. J. Choi et al. Mol. Phylogenet. Evol. 40:400, 2006. (2) Y. J. Choi et al. Fungal Divers. 27:11, 2007. (3) Y. J. Choi et al. Plant Pathol. J. 27: 192, 2011. (4) D. F. Farr and A. Y. Rossman. Fungal Databases. Syst. Mycol. Microbiol. Lab., Online publication, ARS, USDA, Retrieved November 15, 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 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 Leaf Spot Caused by Cercospora fukushiana on New Guinea Impatiens in Korea.

New Guinea impatiens, Impatiens hawkeri W. Bull, is widely cultivated as a potted plant and garden plant. In July 2013, hundreds of young plants (cv. Fanfare) showing symptoms of leaf spot with approximately 50% incidence were found in polyethylene tunnels in Yongin City, Korea. Leaf spots were circular to oblong, reaching 6 mm or more in diameter. The spots were initially uniformly brown to reddish brown, turning gray with reddish brown margin. Diseased plants defoliated prematurely and were abandoned without marketing due to signs of discoloration and yellowing on leaves. A cercosporoid fungus was consistently observed in association with disease symptoms. Stromata were brown, small, and composed of a few swollen hyphal cells. Conidiophores were emerging through the cuticle, fasciculate (n = 2 to 20), olivaceous to brown, paler toward the apex, straight to mildly curved, geniculate, 30 to 260 µm long, 3.5 to 5 µm wide, 1- to 6-septate, and with conspicuous conidial scars. Conidia were hyaline and acicular. Smaller conidia were straight and longer conidia were mildly curved. Conidia were subacute to obtuse at the apex, truncate to obconically truncate at the base, 2- to 18-septate, 30 to 320 × 3.5 to 5.5 µm, and with thickened, darkened hila at the base. Morphological characteristics of the fungus were consistent with the previous reports of Cercospora fukushiana (Matsuura) W. Yamam. (1). Voucher specimens were housed in the Korea University herbarium (KUS). An isolate from KUS-F27438 was deposited in the Korean Agricultural Culture Collection (Accession No. KACC47640). Fungal DNA was extracted with DNeasy Plant Mini Kits (Qiagen Inc., Valencia, CA). The complete internal transcribed spacer (ITS) region of rDNA was amplified with the primers ITS1/ITS4 (4) and sequenced. The resulting sequence of 497 bp was deposited in GenBank (Accession No. KJ620981). This showed >99% similarity with sequence of C. fukushiana (EF600954) on I. balsamina from Korea. Isolate of KACC47640 was used in the pathogenicity tests. Hyphal suspensions were prepared by grinding 3-week-old colonies grown on PDA with distilled water using a mortar and pestle. Five plants were inoculated with hyphal suspensions and five plants were sprayed with sterile distilled water. The plants were covered with plastic bags to maintain a relative humidity of 100% for 24 h and then transferred to a 25 ± 2°C greenhouse with a 12-h photoperiod. Typical symptoms of necrotic spots appeared on the inoculated leaves 10 days after inoculation, and were identical to the symptoms observed in the field. C. fukushiana was re-isolated from symptomatic leaf tissues, confirming Koch's postulates. No symptoms were observed on water-inoculated control plants. Previously, leaf spots of Impatiens spp. associated with C. apii, C. balsaminae, and C. fukushiana have been reported (1,2,3). To our knowledge, this is the first report of C. fukushiana on I. hawkeri in Korea. Our observations in the nurseries of I. hawkeri suggest that low humidity with good ventilation as well as plant hygiene in greenhouses might be main strategies for preventing this disease. References: (1) C. Chupp. A Monograph of the Fungus Genus Cercospora. Ithaca, NY, 1953. (2) D. F. Farr and A. Y. Rossman. Fungal Databases. Syst. Mycol. Microbiol. Lab., online publication, ARS, USDA, retrieved March 25, 2014. (3) J. M. Soares et al. Plant Dis. 93:1214, 2009. (4) T. J. White et al. Page 315 in: PCR Protocols: A Guide to Methods and Applications. Academic Press, San Diego, CA, 1990.

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 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 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.