First Report of Fusicoccum aesculi Causing Leaf Spots of Paeonia suffruticosa in Henan Province, China

Tree peony (Paeonia suffruticosa) is regarded as the national flower of China and is cultivated throughout the country. In early August 2010, a moderately severe leaf spot was observed on tree peony cultivated in a garden of Zhengzhou, Henan Province, where approximately 15% of trees were diseased. In 2011, a less damaging leaf spot was also observed in another area of the city with approximately 10% of trees diseased. Early symptoms appeared as small, round, pale-brown lesions on the leaves. Lesions expanded into 5- to 20-mm-diameter spots that were elliptical or irregular, brown to dark brown. A fungus was consistently isolated from the leaf spots on potato dextrose agar (PDA) in grey-black colonies, but produced few pycnidia. Black pycnidia were ostiolate, globose, papillate, formed in uniloculate or multiloculate stromata that were immersed in the leaf, and became erumpent at maturity. Conidiophores or conidiogenous cells were hyaline and cylindrical. Conidia were hyaline, granular, fusoid to ellipsoid, aseptate, with a sub-truncate base, and 20 to 28 × 4.5 to 7.5 μm (mean dimensions of 50 conidia: 24.5 × 5.2 μm). The pathogen was identified as Fusicoccum aesculi, anamorphic stage of Botryosphaeria dothidea, on the basis of morphology (2). The identity of the fungus was confirmed to be F. aesculi by DNA sequence analysis of the internal transcribed spacer (ITS) region (GenBank Accession No. JQ323001), which was 100% identical to those of other F. aesculi isolates (GenBank Accession Nos. GU997686.1 and GU723469.1) (1). Pathogenicity tests were done by inoculating each of 10 leaves on one 7-year-old tree with a mycelial plug (0.5 cm diameter) harvested from the periphery of a 7-day-old colony. An equal number of leaves on the same tree, serving as controls, were mock-inoculated with plugs of PDA medium. Inoculated leaves were covered with plastic for 24 h to maintain high relative humidity and incubated at about 25°C. The plugs were removed after 48 h. After 7 days, 80% of the inoculated leaves showed symptoms identical to those observed in the field under natural conditions, whereas controls remained symptom-free. Reisolation of the fungus from lesions on inoculated leaves confirmed that the causal agent was F. aesculi. Pathogenicity tests were repeated on the other two trees by the same methods with the same results. To our knowledge, this is the first report of F. aesculi infecting P. suffruticosa in China. References: (1) S. Mohali et al. Mycol. Res. 110:405, 2006. (2) B. C. Sutton. The Coelomycetes. CABI Publishing, New York, 1980.

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First Report of Hainesia lythri Causing Leaf Spots of Paeonia suffruticosa in China

Plant Disease ◽

10.1094/pdis-92-3-0486a ◽

2008 ◽

Vol 92 (3) ◽

pp. 486-486

Author(s):

M. Zhang ◽

H. L. Li ◽

A. L. Zhao ◽

J. X. Zhang

Keyword(s):

Leaf Spot ◽

Leaf Tissue ◽

Causal Agent ◽

Plant Diseases ◽

Acer Pseudoplatanus ◽

Paeonia Suffruticosa ◽

Tree Peony ◽

Korean Society ◽

First Report ◽

Leaf Spots

Tree peony (Paeonia suffruticosa) is known as “the king of flowers” for its beautiful and showy flowers. It is regarded as the symbol flower of China and is cultivated throughout the country. During the summer of 2006, a leaf spot was observed on tree peony cultivated in the Zhengzhou area of Henan Province, and in 2007, the leaf spot was observed in the Luoyang area. In some gardens, the leaf spot affected more than 50% of the plants. Early symptoms appeared as small, round, water-soaked lesions on the leaves. Lesions expanded into 5 to 35-mm-diameter spots that were circular or irregular, brown to dark brown, with pale brown margins. Later, the center of some lesions dropped out. Signs of the suspected pathogen were usually seen on the leaf spots after an abundant rainfall. Lesions contained numerous, pale brown, cupulate conidiomata with salmon-colored spore masses. Conidiophores (70 × 1 to 2 μm) were hyaline, branched, septate, and filiform. Conidia (5.5 to 7.5 × 1.5 to 2 μm) were hyaline, aseptate, and cymbiform to allantoid. The pathogen was identified as Hainesia lythri on the basis of the morphology. This fungus infects a wide variety of hosts including P. suffruticosa, Acer pseudoplatanus, Calluna sp., Dissotis paucistellata, Epilobium angustifolium, and Eucalyptus saligna (3). The fungus was isolated on potato dextrose agar (PDA) medium using conidia from conidiomata found on symptomatic leaf tissue; the fungus produced gray-to-brown colonies. Pathogenicity was tested by inoculating 10 leaves on one 5-year-old tree with a mycelia plug from the colony (0.5 cm in diameter); leaves inoculated with plugs of PDA medium served as controls. Inoculated leaves were covered with plastic for 24 h to maintain high relative humidity and incubated at 25 to 28°C. After 5 days, 100% of the inoculated leaves showed symptoms identical to those observed on leaves from P. suffruticosa infected in the field while controls remained symptom free. Reisolation of the fungus from lesions on inoculated leaves confirmed that the causal agent was H. lythri. Thus, we concluded that H. lythri is the causal agent of leaf spots of P. suffruticosa. To our knowledge, this is the first report of H. lythri infecting P. suffruticosa in China. H. lythri has been previously reported on Paeonia in Japan and Korea (1,2). References: (1) W. D. Cho and H. D. Shin, eds. List of Plant Diseases in Korea. 4th ed. Korean Society of Plant Pathology, 2004. (2) M. E. Palm. Mycologia 83:787, 1991. (3) B. C. Sutton. The Coelomycetes. CAB International Publishing, New York, 1980.

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First Report of Leaf Spot of Sweet Basil Caused by Cercospora guatemalensis in Korea

Plant Disease ◽

10.1094/pdis-05-12-0436-pdn ◽

2012 ◽

Vol 96 (10) ◽

pp. 1580-1580

Author(s):

J. H. Park ◽

K. S. Han ◽

J. Y. Kim ◽

H. D. Shin

Keyword(s):

Leaf Spot ◽

Morphological Characteristics ◽

Its Region ◽

Culture Collection ◽

Distilled Water ◽

First Report ◽

Sweet Basil ◽

Organic Farm ◽

Leaf Spots ◽

Close Phylogenetic Relationship

Sweet basil, Ocimum basilicum L., is a fragrant herb belonging to the family Lamiaceae. Originated in India 5,000 years ago, sweet basil plays a significant role in diverse cuisines across the world, especially in Asian and Italian cooking. In October 2008, hundreds of plants showing symptoms of leaf spot with nearly 100% incidence were found in polyethylene tunnels at an organic farm in Icheon, Korea. Leaf spots were circular to subcircular, water-soaked, dark brown with grayish center, and reached 10 mm or more in diameter. Diseased leaves defoliated prematurely. The damage purportedly due to this disease has reappeared every year with confirmation of the causal agent made again in 2011. A cercosporoid fungus was consistently associated with disease symptoms. Stromata were brown, consisting of brown cells, and 10 to 40 μm in width. Conidiophores were fasciculate (n = 2 to 10), olivaceous brown, paler upwards, straight to mildly curved, not geniculate in shorter ones or one to two times geniculate in longer ones, 40 to 200 μm long, occasionally reaching up to 350 μm long, 3.5 to 6 μm wide, and two- to six-septate. Conidia were hyaline, acicular to cylindric, straight in shorter ones, flexuous to curved in longer ones, truncate to obconically truncate at the base, three- to 16-septate, and 50 to 300 × 3.5 to 4.5 μm. Morphological characteristics of the fungus were consistent with the previous reports of Cercospora guatemalensis A.S. Mull. & Chupp (1,3). Voucher specimens were housed at Korea University herbarium (KUS). An isolate from KUS-F23757 was deposited in the Korean Agricultural Culture Collection (Accession No. KACC43980). 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 sequence of 548 bp was deposited in GenBank (Accession No. JQ995781). This showed >99% similarity with sequences of many Cercospora species, indicating their close phylogenetic relationship. Isolate of KACC43980 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 6 days after inoculation, and were identical to the ones observed in the field. C. guatemalensis was reisolated from symptomatic leaf tissues, confirming Koch's postulates. No symptoms were observed on control plants. Previously, the disease was reported in Malawi, India, China, and Japan (2,3), but not in Korea. To our knowledge, this is the first report of C. guatemalensis on sweet basil in Korea. Since farming of sweet basil has recently started on a commercial scale in Korea, the disease poses a serious threat to safe production of this herb, especially in organic farming. References: (1) C. Chupp. A Monograph of the Fungus Genus Cercospora. Ithaca, NY, 1953. (2) D. F. Farr and A. Y. Rossman. Fungal Databases. Systematic Mycology & Microbiology Laboratory, ARS, USDA. Retrieved from http://nt.ars-grin.gov/fungaldatabases/ , May 5, 2012. (3) J. Nishikawa et al. J. Gen. Plant Pathol. 68:46, 2002.

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First Report of Leaf Spot Caused by Alternaria alternata on Kiwifruit in Italy

Plant Disease ◽

10.1094/pdis.1999.83.5.487d ◽

1999 ◽

Vol 83 (5) ◽

pp. 487-487 ◽

Cited By ~ 3

Author(s):

L. Corazza ◽

L. Luongo ◽

M. Parisi

Keyword(s):

New Zealand ◽

Alternaria Alternata ◽

Leaf Spot ◽

Southern Italy ◽

Morphological Characteristics ◽

Potato Dextrose Agar ◽

First Report ◽

Leaf Spots ◽

Detached Leaves ◽

Pathogenicity Tests

A leaf spot of kiwifruit (Actinidia deliciosa (A. Chev.) C. F. Liang & A. R. Ferg.) leaves was recently observed on plants of the cultivar Hayward in an orchard near Salerno, in southern Italy. The affected plants showed early severe defoliation. The fungus isolated from the infected leaves was identified as Alternaria alternata (Fr.:Fr.) Keissl., based on conidial morphological characteristics. Pathogenicity tests were made by inoculating detached leaves of male pollinator cultivar Tomuri and the female cultivars Hayward and Bruno with a 7-mm disk taken from actively growing cultures of the fungus on potato dextrose agar (PDA). After 14 days, necrotic leaf spots developed and A. alternata was consistently isolated from the inoculated leaves. A. alternata has been observed as a pathogen on leaves and fruits in New Zealand. In the Mediterranean, it has been reported in Israel (2) and in the island of Crete (1). This is the first report of Alternaria leaf spot on kiwifruit in Italy. References: (1) V. A. Bourbos and M. T. Skoudridakis. Petria 7:111, 1997. (2) A. Sive and D. Resnizky. Alon Hanotea 41:409, 1987.

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First Report of Stem and Leaf Anthracnose on Blueberry Caused by Colletotrichum gloeosporioides in China

Plant Disease ◽

10.1094/pdis-11-12-1056-pdn ◽

2013 ◽

Vol 97 (6) ◽

pp. 845-845 ◽

Cited By ~ 1

Author(s):

C. N. Xu ◽

Z. S. Zhou ◽

Y. X. Wu ◽

F. M. Chi ◽

Z. R. Ji ◽

...

Keyword(s):

Colletotrichum Gloeosporioides ◽

Morphological Characteristics ◽

Its Region ◽

Pathogenic Fungi ◽

Molecular Characteristics ◽

First Report ◽

Potted Plants ◽

Leaf Spots ◽

Pathogenicity Tests ◽

Highbush Blueberries

Blueberry (Vaccinium spp.) is becoming increasingly popular in China as a nutritional berry crop. With the expansion of blueberry production, many diseases have become widespread in different regions of China. In August of 2012, stem and leaf spots symptomatic of anthracnose were sporadically observed on highbush blueberries in a field located in Liaoning, China, where approximately 15% of plants were diseased. Symptoms first appeared as yellow to reddish, irregularly-shaped lesions on leaves and stems. The lesions then expanded, becoming dark brown in the center and surrounded by a reddish halo. Leaf and stem tissues (5 × 5 mm) were cut from the lesion margins and surface-disinfected in 70% ethanol for 30 s, followed by three rinses with sterile water before placing on potato dextrose agar (PDA). Plates were incubated at 28°C. Colonies were initially white, becoming grayish-white to gray with yellow spore masses. Conidia were one-celled, hyaline, and cylindrical with rounded ends, measuring 15.0 to 25.0 × 4.0 to 7.5 μm. No teleomorph was observed. The fungus was tentatively identified as Colletotrichum gloeosporioides (PenZ.) PenZ & Sacc. (teleomorph Glomerella cingulata (Stoneman) Spauld. & H. Schrenk) based on morphological characteristics of the colony and conidia (1). Genomic DNA was extracted from isolate XCG1 and the internal transcribed spacer (ITS) region of the ribosomal DNA (ITS1–5.8S-ITS2) was amplified with primer pairs ITS1 and ITS4. BLAST searches showed 99% identity with C. gloeosporioides isolates in GenBank (Accession No. AF272779). The sequence of isolate XCG1 (C. gloeosporioides) was deposited into GenBank (JX878503). Pathogenicity tests were conducted on 2-year-old potted blueberries, cv. Berkeley. Stems and leaves of 10 potted blueberry plants were wounded with a sterilized needle and sprayed with a suspension of 105 conidia per ml of sterilized water. Five healthy potted plants were inoculated with sterilized water as control. Dark brown lesions surrounded by reddish halos developed on all inoculated leaves and stems after 7 days, and the pathogen was reisolated from lesions of 50% of inoculated plants as described above. The colony and conidial morphology were identical to the original isolate XCG1. No symptoms developed on the control plants. The causal agent of anthracnose on blueberry was identified as C. gloeosporioides on the basis of morphological and molecular characteristics, and its pathogenicity was confirmed with Koch's postulates. Worldwide, it has been reported that blueberry anthracnose might be caused by C. acutatum and C. gloeosporioides (2). However, we did not isolate C. acutatum during this study. To our knowledge, this is the first report of stem and leaf anthracnose of blueberry caused by C. gloeosporioides in China. References: (1) J. M. E. Mourde. No 315. CMI Descriptions of Pathogenic Fungi and Bacteria. Kew, Surrey, UK, 1971. (2) N. Verma, et al. Plant Pathol. 55:442, 2006.

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First Report of Leaf Spot Caused by Phyllosticta yuccae on Yucca filamentosa in Brazil

Plant Disease ◽

10.1094/pdis-04-13-0384-pdn ◽

2013 ◽

Vol 97 (9) ◽

pp. 1257-1257 ◽

Cited By ~ 1

Author(s):

A. D. A. Silva ◽

D. B. Pinho ◽

B. T. Hora Junior ◽

O. L. Pereira

Keyword(s):

Leaf Spot ◽

Its Region ◽

The United States ◽

Leaf Spot Disease ◽

Infected Leaf ◽

Single Spore ◽

First Report ◽

Leaf Spots ◽

Slime Layer ◽

Pure Cultures

Yucca filamentosa L. (Agavaceae), commonly known as Adam's needle, is known in Brazil as “agulha-de-adão.” It is an ornamental garden plant with medicinal properties (4). In 2010, 100% of Y. filamentosa seedlings and plants were observed with a severe leaf spot disease in two ornamental nurseries located in the municipality of Viçosa, Minas Gerais, Brazil. Initially, lesions were dark brown, elliptical, and scattered, and later became grayish at the center with a reddish brown margin, irregular and coalescent. Infected leaf samples were deposited in the herbarium at the Universidade Federal de Viçosa (Accession Nos. VIC32054 and VIC32055). A fungus was isolated from the leaf spots and single-spore pure cultures were obtained on potato dextrose agar (PDA). The sporulating single-spore cultures were deposited at the Coleção de Culturas de Fungos Fitopatogênicos “Prof. Maria Menezes” (CMM 1843 and CMM 1844). On the leaf, the fungus produced pycnidial conidiomata that were scattered or gregarious, usually epiphyllous, immersed, dark brown, unilocular, subglobose, and 95 to 158 × 108 to 175 μm, with a minute, subcircular ostiole. Conidiogenous cells were blastic, hyaline, conoidal, or short cylindrical. Conidia were aseptate, hyaline, smooth walled, coarsely granular, broadly ellipsoidal to subglobose or obovate, usually broadly rounded at both ends, occasionally truncate at the base or indented slightly at the apex, and 7.5 to 13.5 × 6 to 10 μm. Conidia were also surrounded by a slime layer, usually with a hyaline, flexuous, narrowly conoidal or cylindrical, mucilaginous apical appendage that was 10 to 16 μm long. Spermatia were hyaline, dumbbell shaped to cylindrical, both ends bluntly rounded, and 3 to 5 × 1 to 1.5 μm. These characteristics matched well with the description of Phyllosticta yuccae Bissett (1). To confirm this identification, DNA was extracted using a Wizard Genomic DNA Purification Kit and amplified using primers ITS1 and ITS4 (2) for the ITS region (GenBank Accession Nos. JX227945 and JX227946) and EF1-F and EF2-R (3) for the TEF-1α (JX227947 and JX227948). The sequencing was performed by Macrogen, South Korea. The ITS sequence matched sequence No. JN692541, P. yuccae, with 100% identity. To confirm Koch's postulates, four leaves of Y. filamentosa (five plants) were inoculated with 6-mm-diameter plugs from a 7-day-old culture growing on PDA. The leaves were covered with plastic sack and plants were maintained at 25°C. In a similar manner, fungus-free PDA plugs were placed on five control plants. Symptoms were consistently similar to those initially observed in the nurseries and all plants developed leaf spots by 15 days after inoculation. P. yuccae was successfully reisolated from the symptomatic tissue and control plants remained symptomless. P. yuccae has been previously reported in Canada, the Dominican Republic, Guatemala, Iran, and the United States of America. To our knowledge, this is the first report of P. yuccae causing disease in Y. filamentosa in Brazil and it may become a serious problem for the nurseries, due to the severity of the disease and the lack of chemical products to control this pathogen. References: (1) J. Bissett. Can. J. Bot. 64:1720, 1986. (2) M. A. Innis et al. PCR Protocols: A guide to methods and applications. Academic Press, 1990. (3) Jacobs et al. Mycol. Res. 108:411, 2004. (4) H. Lorenzi and H. M. Souza. Plantas Ornamentais no Brasil. Instituto Plantarum, 2001.

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First Report of Corynespora cassiicola Causing Leaf Spot of Cassava in China

Plant Disease ◽

10.1094/pdis-94-7-0916a ◽

2010 ◽

Vol 94 (7) ◽

pp. 916-916 ◽

Cited By ~ 1

Author(s):

X.-B. Liu ◽

T. Shi ◽

C.-P. Li ◽

J.-M. Cai ◽

G.-X. Huang

Keyword(s):

Leaf Spot ◽

Morphological Characteristics ◽

Its Region ◽

Pathogenic Fungi ◽

Commonwealth Mycological Institute ◽

Corynespora Cassiicola ◽

Single Spore ◽

First Report ◽

Leaf Spots ◽

Main Vein

Cassava (Manihot esculenta) is an important economic crop in the tropical area of China. During a survey of diseases in July and September of 2009, leaf spots were observed on cassava plants at three separate plantations in Guangxi (Yunfu and Wuming) and Hainan (Baisha) provinces. Circular or irregular-shaped leaf spots were present on more than one-third of the plants. Spots were dark brown or had white papery centers delimited by dark brown rims and surrounded by a yellow halo. Usually, the main vein or small veinlets adjacent to the spots were dark. Some defoliation of plants was evident at the Wuming location. A fungus was isolated from symptomatic leaves from each of the three locations and designated CCCGX01, CCCGX02, and CCCHN01. Single-spore cultures of these isolates were incubated on potato dextrose agar (PDA) for 7 days with a 12-h light/dark cycle at a temperature of 28 ± 1°C. Conidiophores were straight to slightly curved, unbranched, and pale to light brown. Conidia were formed singly or in chains, obclavate to cylindrical, straight or curved, subhyaline-to-pale olivaceous brown, 19.6 to 150.3 μm long and 5.5 to 10.7 μm wide at the base, with 4 to 13 pseudosepta. Morphological characteristics of the specimen and their conidia were similar to the descriptions for Corynespora cassiicola (2). The isolate CCCGX01 was selected as a representative for molecular identification. Genomic DNA was extracted by the cetyltrimethylammoniumbromide protocol (3) from mycelia and used as a template for amplification of the internal transcribed spacer (ITS) region of rDNA with primer pair ITS1/ITS4. The sequence (GenBank Accession No. GU138988) exactly matched several sequences (e.g., GenBank Accession Nos. FJ852715, EF198117, and AY238606) of C. cassiicola (1). Young, healthy, and fully expanded green leaves of cassava cv. SC205 were surface sterilized. Ten leaves were inoculated with 10-μl drops of 104 ml suspension of conidia and five leaves were inoculated with the same volume of sterile water to serve as controls. After inoculation, leaves were placed in a dew and dark chamber for 36 h at 25°C and subsequently transferred to the light for 5 days. All inoculated leaves with isolates showed symptoms similar to those observed in natural conditions, whereas the controls remained symptom free. The morphological characteristics of reisolated conidia that formed on the diseased parts were identical with the nature isolates. To our knowledge, this is the first report of leaf spot caused by C. cassiicola on cassava in China. References: (1) L. J. Dixon et al. Phytopathology 99:1015, 2009. (2) M. B. Ellis et al. Corynespora cassiicola. No. 303 in: CMI Description of Pathogenic Fungi and Bacteria. Commonwealth Mycological Institute, Kew, UK 1971. (3) J. R. Xu et al. Genetics 143:175, 1996.

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First Report of Circular Leaf Spot of Persimmon Caused by Mycosphaerella nawae in Spain

Plant Disease ◽

10.1094/pdis-94-3-0374b ◽

2010 ◽

Vol 94 (3) ◽

pp. 374-374 ◽

Cited By ~ 11

Author(s):

M. Berbegal ◽

A. Pérez-Sierra ◽

J. Armengol ◽

C. S. Park ◽

J. García-Jiménez

Keyword(s):

Leaf Spot ◽

Its Region ◽

Morphological Characters ◽

Diospyros Kaki ◽

Korean Isolate ◽

Individual Tree ◽

First Report ◽

Leaf Spots ◽

Fallen Leaves ◽

Dark Green

Production of persimmon (Diospyros kaki L. f.) has increased significantly during the last decade in Spain as a profitable alternative for fruit growers. In August 2008, after a mild and rainy spring, symptoms of a new disease were observed in commercial persimmon fields located in Valencia Province (eastern-central Spain). Symptoms included circular necrotic spots on the leaves and defoliation. Early fruit maturation and premature abscission were associated with early symptom development in the trees. A fungus was consistently isolated from the margins of leaf lesions. All isolates obtained were hyphal-tipped twice and transferred to potato dextrose agar (PDA). The cultures grew slowly and reached a diameter of 21 to 29 (mean 26) mm within 4 weeks on PDA at 25°C in the dark. Mycelium was initially dark green and ultimately became dark gray to black. Several media and incubation conditions were tested to induce sporulation, but conidia formation was not observed. In April 2009, mature spherical pseudothecia were observed in lesions on fallen leaves that had remained in affected fields during the winter. Ascospores were uniseptate and mostly spindle shaped, 10 to 11.5 (mean 10.3) μm long, and 3 to 3.9 (mean 3.4) μm wide. Fungal colonies obtained from the ascospores were identical to those isolated from the leaf lesions. Morphological characters observed matched those described for the pathogen Mycosphaerella nawae Hiura & Ikata (1). In Korea, the circular leaf spot of persimmon caused by M. nawae was considered an economically important disease in the 1990s, especially in the southern regions (2). Sequences of the internal transcribed spacer (ITS) region of the rDNA were obtained for isolates MY2 and MY3 and deposited in GenBank (Accession Nos. GQ465767 and GQ465768). These sequences were identical to each other and to the sequence obtained from a Korean isolate of M. nawae. Symptoms of the disease were reproduced after inoculation of 2-year-old persimmon trees growing in individual pots. A ground mycelial suspension (5 × 105 CFU ml–1) of strain MY2 was sprayed onto 20 potted trees (200 ml per individual tree) in late May of 2009. Ten trees were sprayed with sterile distilled water as a control. Trees were incubated at 20°C in a growth chamber with a 12-h photoperiod and covered with a semitransparent plastic hood for the first 10 days after inoculation, after which the plastic was punctured for ventilation and trees were incubated at 22°C. The first symptoms (small circular spots on the leaves) appeared on inoculated trees 15 days after inoculation. One month after inoculation, all inoculated trees showed circular leaf spots and severe defoliation, whereas noninoculated trees remained healthy. M. nawae was successfully reisolated from the lesions. To our knowledge, this is the first report of M. nawae causing circular leaf spot of persimmon in Spain. References: (1) J. H. Kwon et al. Plant Dis. Agric. 1:18, 1995. (2) J. H. Kwon et al. Korean J. Plant Pathol. 14:397, 1998.

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First Report of Pestalotiopsis microspora Causing Leaf Spot of Hidcote (Hypericum patulum) in Japan

Plant Disease ◽

10.1094/pdis-94-8-1064b ◽

2010 ◽

Vol 94 (8) ◽

pp. 1064-1064 ◽

Cited By ~ 3

Author(s):

M. Zhang ◽

H. Y. Wu ◽

T. Tsukiboshi ◽

I. Okabe

Keyword(s):

Leaf Spot ◽

Morphological Characteristics ◽

Its Region ◽

Basal Cells ◽

Single Spore ◽

Management Options ◽

First Report ◽

Leaf Spots ◽

Plastic Bags ◽

Pestalotiopsis Microspora

Hidcote, Hypericum patulum Thunb. ex Murray, is a deciduous shrub that is cultivated as an ornamental in landscape gardens and courtyards in Japan. In early August 2008, severe leaf spotting was observed on plants growing in a courtyard in Nasushiobara, Tochigi, Japan. More than 30% of the leaves on five shrubs exhibited leaf spot symptoms. Small, round, pale brown lesions were initially observed. Later, they expanded to 5 to 12 mm in diameter, round to irregular-shaped with pale brown centers and dark brown margins. Under continuously wet or humid conditions, black acervuli developed on the leaf lesions. Conidia were straight or slightly curved, fusiform to clavate, and five-celled with constrictions at the septa. Conidia ranged from 17 to 21 × 5 to 8 μm with hyaline apical and basal cells. Fifteen percent of apical cells had two and the rest had three appendages (setulae) ranging from 10 to 21 μm long. The basal hyaline cell tapered into a 2 to 4 μm pedicel. The three median cells ranged from light or dark brown to olive green. These morphological characteristics matched those of Pestalotiopsis microspora (Speg.) G.C. Zhao & N. Li (1,2). The identity of the fungus was confirmed by DNA sequencing of the internal transcribed spacer (ITS) region (GenBank Accession No. GU908473) from single-spore isolates, which revealed 100% homology with those of other P. microspora isolates (e.g., GenBank Accession Nos. FJ459950 and DQ456865). Koch's postulates were confirmed using leaves of three detached branches of a field-grown asymptomatic plant of H. patulum. Thirty leaves of each branch were inoculated by placing mycelial plugs obtained from the periphery of 7-day-old single-spore cultures on the leaf surface. Potato dextrose agar plugs without mycelium served as controls. Leaves on branches were covered with plastic bags for 24 h to maintain high relative humidity in a greenhouse (approximately 24 to 28°C). After 5 days, all inoculated leaves showed symptoms identical to those described above, whereas control leaves remained symptom free. Reisolation of the fungus from lesions on inoculated leaves confirmed that the causal agent was P. microspora. To our knowledge, this is the first report of leaf spots on H. patulum caused by P. microspora in Japan. Management options may have to be developed and implemented to protect Hidcote plants in areas where leaf spot cannot be tolerated. References: (1) P. A. Saccardo. Sylloge Fungorum III:789, 1884. (2) G. C. Zhao and N. Li. J. Northeast For. Univ. 23(4):21, 1995.

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First Report of a Leaf Spot on Hazel Leaves Caused by Phyllosticta coryli in Liaoning Province of China

Plant Disease ◽

10.1094/pdis-02-13-0213-pdn ◽

2013 ◽

Vol 97 (9) ◽

pp. 1254-1254 ◽

Cited By ~ 10

Author(s):

J. Sun ◽

D.-M. Wang ◽

X.-Y. Huang ◽

Z.-H. Liu

Keyword(s):

Leaf Spot ◽

Control Strategies ◽

Morphological Characteristics ◽

Leaf Tissue ◽

Its Region ◽

Liaoning Province ◽

Single Spore ◽

First Report ◽

Leaf Spots ◽

Microscopic Morphology

Hazel (Corylus heterophylla Fischl) is an important nut tree grown in China, especially in Liaoning Province, and is rich in nutritional and medicinal values. In August 2011, leaf spotting was observed on hybrid hazel (Dawei) leaves in Paotai Town, Wafangdian County of Liaoning Province. By August 2012, the disease had spread to Zhangdang Town, Fushun County. Symptoms initially appeared on both sides of leaves as pinpoint brown spots, which enlarged and developed into regular, dark brown lesions, 3 to 9 mm in diameter. The lesions were lighter in color in the center compared to the margin. To identify the pathogen, leaf pieces (3 to 5 mm) taken from the margins, including both symptomatic and healthy portions of leaf tissue, were surface-disinfected first in 75% ethanol for 5 s, next in 0.1% aqueous mercuric chloride for 50 s, and then rinsed with sterilized water three times. Leaf pieces were incubated on potato dextrose agar (PDA) at 25°C for 14 days in darkness. Single spore isolates were obtained from individual conidia. For studies of microscopic morphology, isolates were grown on synthetic nutrient agar (SNA) in slide cultures. Colonies grew up to 45 to 48 mm in diameter on PDA after 14 days. Pycnidia appeared on the colonies after 12 days. Conidiophores were short. Pycnidia were dark brown, subglobose, and 150 to 205 μm in diameter. Conidia were unicellular, colorless, ovoid to oval, and from 2.4 to 4.5 × 1.6 to 2.4 μm. On the basis of these morphological characteristics, the isolates were tentatively identified as Phyllosticta coryli Westend (2). The rDNA internal transcribed spacer (ITS) region was amplified using primers ITS1 and ITS4 and sequenced (GenBank Accession No. KC196068). The 490-bp amplicons had 100% identity to an undescribed Phyllosticta species isolated from Cornus macrophylla in Gansu, Tianshui, China (AB470897). On the basis of morphological characteristics and nucleotide homology, the isolate was tentatively identified as P. coryli. Koch's postulates were fulfilled in the growth chamber on hazelnut leaves inoculated with P. coryli conidial suspensions (107 conidia ml–1). Eight inoculated 1-year-old seedlings (Dawei) were incubated under moist conditions for 8 to 10 days at 25°C. All leaf spots that developed on inoculated leaves were similar in appearance to those observed on diseased hazel leaves in the field. P. coryli was recovered from lesions and its identity was confirmed by morphological characteristics. P. coryli was first reported as a pathogen of hazel leaves in Bull of Belgium (2). In China, P. coryli was first reported on Corylus heterophylla Fisch. in Jilin Province (1). To our knowledge, this is the first report of P. coryli causing leaf spot on hybrid hazel in Liaoning Province of China. The outbreak and spread of this disease may decrease the yield of hazelnut in northern regions of China. More studies are needed on control strategies, including the possible resistance of hazel cultivars to P. coryli. References: (1) Y. Li et al. J. Shenyang Agric. Univ. 25:153, 1994. (2) P. A. Saccardo. Sylloge Fungorum Vol. III, page 31, 1884.

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First Report of Bipolaris peregianensis Causing Leaf Spot of Cynodon dactylon in China

Plant Disease ◽

10.1094/pdis-12-11-1066-pdn ◽

2012 ◽

Vol 96 (6) ◽

pp. 917-917 ◽

Cited By ~ 2

Author(s):

Z. Y. Wang ◽

S. N. Xie ◽

Y. Wang ◽

H. Y. Wu ◽

M. Zhang

Keyword(s):

Leaf Spot ◽

Cynodon Dactylon ◽

Control Strategies ◽

Tap Water ◽

Morphological Characteristics ◽

Its Region ◽

Basal Cells ◽

First Report ◽

Leaf Spots ◽

Plastic Bags

Cynodon dactylon is widely cultivated as a sod crop in warm climates worldwide. In early September 2009, heavy leaf spot infection was observed on C. dactylon from Zhengzhou, Henan, China. Early symptoms appeared as small, elliptical, pale brown lesions on the leaves. Lesions later expanded to 5 to 10 mm long and 1 to 2 mm wide, becoming brown to dark brown. A fungus was consistently isolated from leaf spots on potato dextrose agar (PDA), but with poor sporulation. Morphological characteristics were observed from single-conidium cultures on tap water agar + wheat straw (TWA+W) after 5 to 7 days. Conidiophores were light to medium brown, cylindrical, solitary or clustered, unbranched, usually with basal cells enlarged, and 94.5 to 147.0 × 4.0 to 9.0 μm. Conidia were fusoid, strongly curved, end cells broadly hemiellipsoidal, brown, 58.5 to 84.5 × 13.5 to 18.5 μm, with 6 to 10 septa. These morphological characteristics are similar to those of Bipolaris peregianensis (2). The identity of our fungus was confirmed to be B. peregianensis by DNA sequencing of the internal transcribed spacer (ITS) region (GenBank Accession No. JQ316121), which was 99% homologous to those of other B. peregianensis isolates (= Cochliobolus peregianensis; Accession Nos AF071328 and AF158111) (1). Koch's postulates were performed with the leaves of three pots of C. dactylon. Leaves were sprayed with 1 × 105 conidia/ml of B. peregianensis; an equal number of leaves in the pots of the same plant sprayed with sterile distilled water served as the control. All test plants were covered with plastic bags for 24 h to maintain high relative humidity at 23 to 25°C. After 7 days, more than 50% of inoculated leaves showed symptoms identical to those observed in natural condition, whereas controls remained symptom free. Reisolation of the fungus from lesions on inoculated leaves confirmed that the causal agent was B. peregianensis. To our knowledge, this is the first report of leaf spots caused by B. peregianensis on C. dactylon in China. The disease cycle and the control strategies in the regions are being further studied. References: (1) M. L. Berbee et al. Mycologia 91:964, 1999. (2) A. Sivanesan. Mycol. Pap. 158:1, 1987.

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