M. J. Park

First Report of Powdery Mildew Caused by Erysiphe macleayae on Macleaya microcarpa in Poland

Macleaya microcarpa (Maxim.) Fedde, also known as smallfruit plume poppy, is a perennial herb belonging to the family Papaveraceae. The plant, together with the better-known species M. cordata (Willd.) R. Br., is native to central China and is now planted worldwide for medicinal purposes. In October 2008 and August 2009, dozens of smallfruit plume poppy planted in the Kraków Botanical Garden, Poland, were found to be severely infected with a powdery mildew. White colonies with abundant sporulation developed on both sides of leaves and young stems, forming circular to irregular patches. Infections caused leaf yellowing and premature defoliation. The damage has been observed every year since 2009. Representative voucher specimens were deposited in the fungal herbarium of the W. Szafer Institute of Botany of the Polish Academy of Sciences (KRAM) and the Korea University herbarium (KUS). Appressoria on the mycelia were lobed, often in pairs. Conidiophores composed of three to four cells arose from the upper part of creeping hyphae, 65 to 120 × 7 to 10 μm, attenuated toward the base, sub-straight or slightly flexuous in foot-cells, and produced conidia singly. Conidia were hyaline, oblong-elliptical to doliiform, 25 to 38 × 12 to 18 μm with a length/width ratio of 1.8 to 2.6; lacked fibrosin bodies; and produced germ tubes on the subterminal position with club-shaped or lobed appressoria. The conidial surface was wrinkled to irregularly reticulate. No chasmothecia were found. The structures described above match well with the anamorph of Erysiphe macleayae R.Y. Zheng & G.Q. Chen (3). To confirm the identity of the causal fungus, the internal transcribed spacer (ITS) region of rDNA from KUS-F24459 was amplified using primers ITS5 and P3 (4) and directly sequenced. The resulting sequence of 553 bp was deposited in GenBank (Accession No. JQ681217). A GenBank BLAST search using the present data revealed >99% sequence similarity of the isolate with E. macleayae on M. cordata from Japan (AB016048). Pathogenicity was confirmed through inoculation by gently pressing diseased leaves onto leaves of three healthy potted plants. Three noninoculated plants served as controls. Plants were maintained in a greenhouse at 25°C. Inoculated plants developed signs and symptoms after 7 days, whereas the control plants remained healthy. The fungus present on the inoculated plants was morphologically identical to that originally observed on diseased plants. The powdery mildew infections of M. cordata associated with E. macleayae have been recorded in China and Japan (2), and more recently in Germany (1,3). To our knowledge, this is the first report of E. macleayae on M. microcarpa globally as well as in Poland. This mildew species was described in China and is endemic to Asia, where chasmothecia of the fungus were found. Only recently have powdery mildews been found on M. cordata in Germany (1,3) and now on M. microcarpa in Poland, indicating the fungus is spreading in Europe. References: (1) N. Ale-Agha et al. Schlechtendalia 17:39, 2008. (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/ , February 7, 2012. (3) A. Schmidt and M. Scholler. Mycotaxon 115:287, 2011. (4) S. Takamatsu et al. Mycol. Res. 113:117, 2009.

First report of Corynespora leaf spot on beach vitex caused by Corynespora cassiicola in Korea

Beach vitex, Vitex rotundifolia L. fil., is a perennial that grows in temperate and tropical areas of the Pacific. In areas where it has been introduced outside of its native range, beach vitex has proven to be an invasive species. This plant dominates dune ecosystems leading to a reduction in the prevalence of native species (1). In October 2010, previously unknown leaf spots were observed on the beach vitex growing on sand dunes in Incheon City of Korea. The same symptoms were repeated in 2011 and 2012. In September 2012, the same leaf spots were found on the beach vitex in Samcheok and Gyeongju in Korea. The symptoms usually started as small, dark brown to purplish leaf spots with more or less concentric rings, eventually causing leaf blights or yellowing with 50% or more defoliation by the end of September. Representative samples (n = 6) 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 occasionally in clusters, 80 to 500 × 5 to 9 μm, and mostly arose on the abaxial surface of symptomatic leaves. Conidia were borne singly or in short chains of 2 to 4, ranging from cylindrical to broadest at the base and tapering apically, straight to slightly curved, pale olivaceous brown, 1 to 12 pseudoseptate, 50 to 250 × 8 to 18 μm, each with a conspicuous thickened hilum. On potato dextrose agar (PDA), 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 (3). Two monoconidial isolates were preserved at the Korean Agricultural Culture Collection (Accession Nos. KACC45712 and KACC46953). Isolate KACC45712 was used for molecular works and pathogenicity test. 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 520 bp was deposited in GenBank (Accession No. KC987359). A BLAST search in GenBank revealed that the sequence showed 100% identity with those of C. cassiicola (e.g., JQ801302). To conduct a pathogenicity test, a conidial suspension (ca. 2 × 104 conidia/ml) was prepared by harvesting conidia from 2-week-old cultures, and the suspension was sprayed onto the leaves of three healthy seedlings. Inoculated plants were kept in humid chambers for 48 h in a glasshouse. After 5 days, typical leaf spot symptoms started to develop on the leaves of all three inoculated plants. C. cassiicola was reisolated from the lesions, confirming Kochs postulates. Control plants treated with sterile water remained symptomless. C. cassiicola is cosmopolitan with a very wide host range (2,4). To our knowledge, C. cassiicola has not been reported on Vitex spp. anywhere in the world. According to field observations in Korea, Corynespora leaf spot was most severe in August and September, especially following a prolonged period of moist weather. C. cassiicola may be a potential biocontrol agent for this highly invasive species. References: (1) M. C. Cousins et al. Invasive Plant Sci. Manag. 3:340, 2010. (2) L. J. Dixon et al. Phytopathology 99:1015, 2009. (3) M. B. Ellis. Dematiaceous Hyphomycetes. Commonw. Mycol. Inst.: Kew, UK, 1971. (4) D. F. Farr and A. Y. Rossman. Fungal Databases. Syst. Mycol. Microbiol. Lab., Online publication, ARS, USDA, Retrieved April 30, 2013.

First report of powdery mildew caused by Oidium hortensiae on Mophead Hydrangea in Korea

Hydrangea macrophylla (Thunb.) Ser., known as mophead hydrangea, is native to Japan and is used as a potted ornamental or is planted for landscaping in gardens worldwide. In May 2011, powdery mildew occurred on potted mophead hydrangea cv. Emerald plants in polyethylene-film-covered greenhouses in Icheon, Korea. Heavily infected plantings were unmarketable, mainly due to purplish red discoloration and crinkling of leaves. Such powdery mildew symptoms on mophead hydrangea in gardens had been often found in Korea since 2001, and the collections (n = 10) were deposited in the Korea University herbarium (KUS). In all cases, there was no trace of chasmothecia formation. Mycelium was effuse on both sides of leaves, young stems, and flower petals. Appressoria were well developed, lobed, and solitary or in opposite pairs. Conidiophores were cylindrical, 70 to 145 × 7.5 to 10 μm, and composed of three to four cells. Foot-cells of conidiophores were straight to sub-straight, cylindric, short, and mostly less than 30 μm long. Conidia produced singly were ellipsoid to oval, 32 to 50 × 14 to 22 μm with a length/width ratio of 1.7 to 2.8, lacked fibrosin bodies, and showed angular/rectangular wrinkling of outer walls. Germ tubes were produced on the perihilar position of conidia. Primary conidia were apically conical, basally rounded to subtruncate, 32 to 42 × 14 to 18 μm, and thus generally smaller than the secondary conidia. The morphological characteristics are consistent with previous descriptions of Oidium hortensiae Jørst. (3,4). To confirm the identification, the complete internal transcribed spacer (ITS) region of rDNA from KUS-F25514 was amplified with primers ITS5 and P3 and directly sequenced. The resulting sequence of 694 bp was deposited in GenBank (Accession No. JQ669944). There was no ITS sequence data known from powdery mildews on Hydrangea. Therefore, this is the first sequence of O. hortensiae submitted to GenBank. Nevertheless, a GenBank BLAST search of this sequence showed >99% similarity with those of Oidium spp. recorded on crassulacean hosts (e.g. GenBank Accession Nos. EU185641 ex Sedum, EU185636 ex Echeveria, and EU185639 ex Dudleya) (2), suggesting their close phylogenetic relationship. Pathogenicity was confirmed through inoculation by gently pressing diseased leaves onto leaves of five healthy potted mophead hydrangea cv. Emerald plants. Five noninoculated plants of the same cultivar served as controls. 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 morphologically identical to that originally observed on diseased plants, fulfilling Kochs postulates. Occurrence of powdery mildew disease on mophead hydrangea is circumglobal (1). To our knowledge, this is the first report of powdery mildew disease caused by O. hortensiae on mophead hydrangea in Korea. Powdery mildew infections in Korea pose a serious threat to the continued production of quality potted mophead hydrangea in polyethylene-film-covered greenhouses. References: (1) D. F. Farr and A. Y. Rossman. Fungal Databases, Systematic Mycology and Microbiology Laboratory, ARS, USDA. Retrieved March 19, 2012, from http://nt.ars-grin.gov/fungaldatabases/ . (2) B. Henricot. Plant Pathol. 57:779, 2008. (3) A. Schmidt and M. Scholler. Mycotaxon 115:287, 2011. (4) S. Tanda. J. Agric. Sci. Tokyo Univ. Agric. 43:253, 1999.

Security Analysis on Password Authentication System of Web Sites

ABSTRACT Portal site is not only providing search engine and e-mail service but also various services including blog, news, shopping, and others. The fact that average number of daily login for Korean portal site Naver is reaching 300 million suggests that many people are using portal sites. With the increase in number of users followed by the diversity in types of services provided by portal sites, the attack is also increasing. Most of studies of password authentication is focused on threat and countermeasures, however, in this study, we analyse the security threats and security requirement of membership, login, password reset first phase, password reset second phase. Also, we measure security score with common criteria of attack potential. As a result, we compare password authentication system of domestic and abroad portal sites. Keywords:Password Authentication System of Web Portal, Threat of Web Portal, Security Requirement of Web Portal, Attack Potential 웹사이트 패스워드 인증 시스템의 보안성 분석

First report of brown spot needle blight on Pinus thunbergii caused by Lecanosticta acicola in Korea.

Pinus thunbergii Parl., known as black pine, is a pine native to coastal areas of Japan and Korea. Because of its resistance to pollution and salt, it is planted as windbreakers along the coast. In March 2010, needle blight symptoms were found on several trees of black pine in Naju, southern Korea. Further surveys in 2010 and 2011 showed that these symptoms are rather common but disease incidence is less than 1%. Small, circular grayish green spots first appeared on the needles. The spots developed into brown bands reaching 1 to 2 mm long, sometimes with yellow margins. Dark olivaceous to dark grayish stromata were erumpent and conspicuous on the brown lesions in the later stage of disease development. Conidiophores were simple or occasionally branched, 1- to 2-septate, pale brown to olivaceous brown, and smooth walled. Conidia (n = 30) were olivaceous brown to grayish brown, verrucose, thick-walled, mildly curved, allantoid to fusiform, one- to five-septate (mostly three-septate), and 20 to 45 × 3.5 to 5 μm. Morphological characteristics of the fungus were consistent with those of Lecanosticta acicola (Thüm.) Syd. (anamorph of Mycosphaerella dearnessii M.E. Barr), previously known as the causal agent of brown spot needle blight of pines (2,4). The teleomorph was not observed. On potato dextrose agar, single-spore cultures of three isolates were obtained from conidia sporulating on needles. An isolate was preserved at the Korean Agricultural Culture Collection (Accession No. KACC44982). Genomic DNA was extracted using the DNeasy Plant Mini DNA Extraction Kit (Qiagen Inc., Valencia, CA) and the complete internal transcribed spacer (ITS) region of rDNA was amplified and sequenced with the primers ITS1/ITS4. The resulting ITS sequence of 543 bp was deposited in GenBank (Accession No. JQ245448). A GenBank BLAST search produced an exact match for the sequences of M. dearnessii (= L. acicola) on P. mugo Tura from Lithuania (HM367708) and P. radiata D. Don from France (GU214663), with 100% sequence similarity. To conduct a pathogenicity test, a conidial suspension (approx. 2 × 105 conidia/ml) was prepared by harvesting conidia from 5-week-old cultures of KACC44982 and sprayed onto the needles of five 3-year-old healthy seedlings. Five noninoculated seedlings of the same age served as controls. Inoculated and noninoculated plants were kept in humid chambers for 48 h in a glasshouse. After 28 days, typical leaf spot symptoms started to develop on the needles of inoculated plants. The fungus, L. acicola, was reisolated from those lesions, confirming Kochs postulates. No symptoms were observed on control plants. The disease has been previously reported on several species of Pinus in the Americas (1) and recently in China (3), Japan (4), and Europe (2). To our knowledge, this is the first report of the Lecanosticta-Pinus association in Korea. Occurrence of the disease in Korea is a new threat to the health of black pine, especially in nursery plots. References: (1) D. F. Farr and A. Y. Rossman. Fungal Databases. Systematic Mycology and Microbiology Laboratory, ARS, USDA. Retrieved from http://nt.arsgrin.gov/fungaldatabases/ December 2011. (2) L. Jankovsky et al. Plant Protect. Sci. 45:16, 2009. (3) C. Li et al. J. Nanjing Inst. For. 1986:11, 1986. (4) Y. Suto and D. Ougi. Mycoscience 39:319, 1998.

First Report of Corynespora Leaf Spot on Ailanthus altissima Caused by Corynespora cassiicola in Korea

Ailanthus altissima (Mill.) Swingle, known as tree-of-heaven, is a deciduous tree belonging to the family Simaroubaceae, which is native to both northeast and central China and Taiwan. The trees often have the ability to replace indigenous plants and disrupt native ecosystems (3). In August 2010, a leaf spot disease was observed on young trees in Yangpyeong, Korea. Field observation in 2010 and 2011 showed that infections are common on 1- or 2-year-old trees. Adult trees were rarely infected. Symptoms usually started at the margin of leaves and expanded into irregular, dark brown leaf spots, eventually causing significant premature defoliation. Representative samples were deposited in the herbarium of Korea University (KUS-F25174 and -F25304). Conidiophores of fungi observed microscopically on the leaf spots were erect, brown to dark brown, single or occasionally in clusters, 80 to 550 × 5 to 8 μm, and mostly arose on the abaxial surface of symptomatic leaves. Conidia were borne singly or in short chains of two to four, ranging from cylindrical to broadest at the base and tapering apically, straight to slightly curved, pale olivaceous brown, 3 to 18 pseudoseptate, 70 to 450 × 8 to 22 μm, each with a conspicuous thickened hilum. On potato dextrose agar, single-spore cultures of five isolates were identified as Corynespora cassiicola (Berk. & M.A. Curtis) C.T. Wei on the basis of morphological and cultural characteristics (1,4). A monoconidial isolate was preserved at the Korean Agricultural Culture Collection (Accession No. KACC45510). Genomic DNA was extracted with 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 with an ABI Prism 337 automatic DNA sequencer (Applied Biosystems, Foster, CA). The resulting sequence of 548 bp was deposited in GenBank (Accession No. JN974462). The sequence showed >99% similarity (1-bp substitution) with a sequence of C. cassiicola from Ipomoea batatas (GenBank Accession No. FJ852716). To conduct a pathogenicity test, a conidial suspension (~2 × 104 conidia/ml) was prepared by harvesting conidia from 2-week-old cultures of KACC45510 and the suspension sprayed onto the leaves of three healthy seedlings. Three noninoculated seedlings served as control plants. Inoculated and noninoculated plants were kept in humid chambers for 48 h in a glasshouse. After 5 days, typical leaf spot symptoms started to develop on the leaves of all three inoculated plants. C. cassiicola was reisolated from the lesions, confirming Kochs postulates. No symptoms were observed on control plants. C. cassiicola is cosmopolitan with a very wide host range (2). To our knowledge, C. cassiicola has not been reported on A. altissima anywhere in the world. According to field observations in Korea, Corynespora leaf spot was most severe in August and September, especially following a prolonged period of moist weather. C. cassiicola may be a potential biocontrol agent for this highly invasive tree species. References: (1) M. B. Ellis. Dematiaceous Hyphomycetes. Commonwealth Mycological Institute: Kew, Surrey, England, 1971. (2) D. F. Farr and A. Y. Rossman. Fungal Databases. Systematic Mycology and Microbiology Laboratory, ARS, USDA, Retrieved from http://nt.ars-grin.gov/fungaldatabes/ , October 28, 2011. (3) L. B. Knapp and C. D. Canham. J. Torrey Bot. Soc. 127:307, 2000. (4) J. H. Kwon et al. Plant Pathol. J. 17:180, 2001.

Study on Usable Security of Facebook

Recently, as the widespread use of Facebook through a smartphone or tablet PC, it has increased the threat that contains the malicious code to post a social attacks and comments that use personal information that has been published of Facebook. To solve these problems, Facebook is, by providing a security function, but would like to address these threats, in setting the security function, the security function of the user`s convenience is not considered a properly there is a problem that is not in use. Thus, in this paper, on the basis of the information obtained via the cogTool, on Facebook security features, the user experience by presenting a method that can be quantitatively measured by this, the user convenience It classifies about Facebook security features to decrease.

Practical silicon-surface-protection method using metal layer

The reversal of a silicon chip to find out its security structure is common and possible at the present time. Thanks to reversing, it is possible to use a probing attack to obtain useful information such as personal information or a cryptographic key. For this reason, security-related blocks such as DES (Data Encryption Standard), AES (Advanced Encryption Standard), and RSA (Rivest Shamir Adleman) engines should be located in the lower layer of the chip to guard against a probing attack; in this regard, the addition of a silicon-surface-protection layer onto the chip surface is a crucial protective measure. But, for manufacturers, the implementation of an additional silicon layer is burdensome, because the addition of just one layer to a chip significantly increases the overall production cost; furthermore, the chip size is increased due to the bulk of the secure logic part and routing area of the silicon protection layer. To resolve this issue, this paper proposes a practical silicon-surface-protection method using a metal layer that increases the security level of the chip while minimizing its size and cost. The proposed method uses a shift register for the alternation and variation of the metal-layer data, and the inter-connection area is removed to minimize the size and cost of the chip in a more extensive manner than related methods.

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.

A study on weakness and improvement of Cloud Shredder

Recently, almost all data have been stored and managed by digital types because of development of IT infrastructure. Digital data has the advantage of huge data that can be stored in very small space. However, there is a risk that a large amount of data can be leaked if disk which stored digital data is stolen or lost. Currently, digital data is protected by encryption method to prevent data leaking. However, the encryption method is not enough to protect data because the performance of attack system is higher and the attack methods are various. Therefore, there is a need for a new advanced data protection method. There have been a variety of research methods such as Cloud Shredder which is to maintain local storage and cloud storage for solving this problem. In this paper, we identify the problem of the existing method and propose an advanced method of digital data protection to solve that problem.