scholarly journals First Report of Anthracnose Caused by Colletotrichum gloeosporioides on Schefflera actinophylla in China

Plant Disease ◽  
2013 ◽  
Vol 97 (7) ◽  
pp. 998-998
Author(s):  
J. Huang
Keyword(s):  
Dna Sequence ◽  
Species Complex ◽  
Colletotrichum Gloeosporioides ◽  
Conidial Suspension ◽  
First Report ◽  
Leaf Spots ◽  
Black Spots ◽  
Pathogenicity Tests ◽  
Colletotrichum Gloeosporioides Species Complex ◽  
And Control

In China, in mild to warm climates, Schefflera actinophylla is commonly grown as a decorative tree in gardens. When mature, it has bright red flowers in inflorescences with up to 20 racemes that develop in summer or early autumn. From 2008 to 2011, lesions were observed on young and mature leaves in several locations in Guangzhou, China. The first symptoms were circular, necrotic areas that usually developed into irregular, dry, brown to reddish brown or black spots. Spots often first appeared at or near the margins of leaves. Reproductive bodies of the pathogen appeared as black specks in leaf spots. Under a 10× magnification, black, needle-like fungal structures (setae) were observed in the centers of spots on the upper leaf surface. A fungus was isolated from the lesion and was identified as Colletotrichum gloeosporioides (Penz.) Penz. & Sacc. based on cultural characteristics and conidial morphology (1). The voucher isolates were deposited in the Institute of Plant Pathology, Zhongkai University of Agriculture and Engineering. C. gloeosporioides is a species complex (2) and there is a degree of unresolved aspects of taxonomy in this species complex. Cultures on potato dextrose agar (PDA) had aerial white mycelium that turned gray to grayish black after 10 days at 25°C and a 12-h photoperiod and produced salmon to orange conidial masses. Brown, 80 to 120 μm long setae were observed in the acervulus. Conidia 14.1 to 18.0 × 4.0 to 6.1 μm in size were hyaline, thin-walled, aseptate, granular inside, clavate to slightly navicular in shape with an obtuse apex and a truncate base. To identify the fungus, a 588-bp segment of the ITS1-5.8S-ITS2 rDNA region was amplified by PCR and sequenced. The DNA sequence was submitted to GenBank as KC207404. A BLAST search of the DNA sequence showed 99% identity with accessions AY266389.1, EF423519.1, and HM575258.1 of C. gloeosporioides. Pathogenicity tests were conducted under greenhouse conditions at 25 ± 2°C. A total of 15 leaves from three 1-year-old S. actinophylla plants were inoculated with mycelial PDA plugs that were placed on 0.5-cm2 leaf wounds and then wrapped with Parafilm. Control leaves were treated similarly except that they were inoculated with PDA plugs without the fungus. No symptoms developed on control leaves after 10 days. Foliar lesions on inoculated leaves closely resembled those observed in the field. C. gloeosporioides was reisolated consistently from inoculated leaves. Pathogenicity was also tested by spraying leaves of potted S. actinophylla plants about 30 cm in height with 10 ml of a conidial suspension (1 × 105 conidia/ml) prepared from 7-day-old PDA cultures grown at 25°C. Leaves sprayed with distilled water were used as controls. Three plants were inoculated in each of two experiments and were incubated at 25°C and 90% relative humidity in a growth chamber. Tiny brown spots started to develop on all inoculated leaves 5 days after inoculation and the progression of symptom development was similar to that observed in the field. Control leaves remained asymptomatic. C. gloeosporioides was reisolated from inoculated leaves. To my knowledge, this is the first report of C. gloeosporioides causing anthracnose on S. actinophylla in China. References: (1) B. C. Sutton. The genus Glomerella and its anamorph Colletotrichum. In: Colletotrichum Biology, Pathology and Control. CAB International, Wallingford, UK, 1992. (2) B. S. Weir et al. The Colletotrichum gloeosporioides species complex. Stud. Mycol. 73:115, 2012.

scholarly journals First Report of Colletotrichum gloeosporioides on Russian-thistle

Plant Disease ◽  
1998 ◽  
Vol 82 (12) ◽  
pp. 1405-1405 ◽  
Author(s):  
I. Schwarczinger ◽  
L. Vajna ◽  
W. L. Bruckart
Keyword(s):  
Colletotrichum Gloeosporioides ◽  
Morphological Characteristics ◽  
Ground Level ◽  
Conidial Suspension ◽  
First Report ◽  
High Virulence ◽  
Pathogenicity Tests ◽  
Stem Lesions ◽  
And Control ◽  
The U.S

A pathogen identified as Colletotrichum gloeosporioides (Penz.) Penz. & Sacc. in Penz. was isolated from foliar and stem lesions on Russian-thistle (Salsola tragus Torner ex L.) collected in Bugac, Hungary, in 1996. Symptoms on leaves and stems began as discrete, sunken, 2- to 10-mm-diameter chlorotic spots, followed by formation of circular buff-colored lesions that eventually coalesced, desiccated, and caused plant tissue death above the lesions. Lesions that occurred near ground level usually killed the plant. Salmon-colored spore masses developed in setose acervuli in the center of the necrotic lesions. Conidia were hyaline, one-celled, falcate to nearly straight, and measured 15 to 25 × 5 to 6 μm. The teleomorph stage of the pathogen (Glomerella cingulata (Stoneman) Spauld. & H. Schrenk) was not observed in the field or on inoculated plants. These morphological characteristics of the isolate were consistent with the description of C. gloeosporioides (1). Pathogenicity was proved by completing Koch's postulates in Hungary and the U.S. Inoculation with conidial suspension (106 conidia per ml) sprayed on S. tragus plants in the greenhouse at the three- to four-leaf stage caused severe necrosis and wilting within 6 days and plant death in 2 weeks. Symptoms did not appear on control plants inoculated with sterile, distilled water. Inoculation test was repeated on 6-week-old plants and at the stage of flowering. All treated plants were killed at both stages within 4 weeks. Because of high virulence and host specificity of this isolate of C. gloeosporioides in preliminary pathogenicity tests it is being evaluated for use as a mycoherbicide for Russian-thistle control in the U.S. This is the first report of C. gloeosporioides causing anthracnose on S. tragus. Reference: (1) B. C. Sutton. Pages 1–27 in: Colletotrichum Biology, Pathology and Control. J. A. Bailei and M. J. Jeger, eds. CAB Int., Wallingford, UK, 1992.

scholarly journals First Report of Alternaria Leaf Blight on Bupleurum chinense Caused by Alternaria alternata in China

Plant Disease ◽  
2010 ◽  
Vol 94 (7) ◽  
pp. 918-918
Author(s):  
Z. Zhang ◽  
J. H. Wei ◽  
C. M. Yang ◽  
H. Q. Chen ◽  
C. Sui ◽  
...  
Keyword(s):  
Disease Incidence ◽  
Conidial Suspension ◽  
First Report ◽  
High Soil Moisture ◽  
Leaf Spots ◽  
Black Spots ◽  
Initial Symptoms ◽  
Leaf Tissues ◽  
Pathogenicity Tests ◽  
Symptomatic Leaf

Bupleurum chinense DC. (family Umbelliferae) is an important medicinal herb in traditional Chinese medicine and is cultivated as an economically important plant in China (2). From 2006 to 2009, severe foliar disease was observed on B. chinense in Haidian, Changping, and Shunyi districts, Beijing, China. Approximately 75 to 85% of fields were affected with disease incidence ranging from 65 to 90%. Distribution of the disease in affected B. chinense fields was generally associated with high soil moisture, often corresponding to poor drainage. Initial symptoms first appeared on older leaves as irregularly shaped, minute, dark brown-to-black spots, with yellow borders on the edge of the affected leaflet blade. As the disease progressed, the lesions expanded, causing the leaflets to turn brown, shrivel, and die. Isolations performed on potato dextrose agar (PDA) initially resulted in white colonies. After 7 days of incubation at 25°C, the colonies turned gray or brown. Conidia varied in size from 10 × 6 to 40 × 12 μm, appeared brown to dark brown or olive-brown, were short beaked and borne in long chains, oval and bean-shaped with one to six transverse septa and zero to three longitudinal septa. Sequences of the rDNA from the internal transcribed spacer regions 1 and 2 and the 5.8S gene were amplified using primers ITS1 and ITS4, were obtained from three isolates, and comparisons with GenBank showed 100% similarity with A. alternata (Genbank Accession No. AB470912.1). For pathogenicity tests, three isolates were grown on PDA for 14 days. Inoculations were performed on detached, surface-sterilized, and healthy B. chinense leaflets following the method of Belisario (1). A 5-μl drop of conidial suspension containing 1 × 105 CFU/ml was placed on each leaflet and 12 leaves per isolate were used. Leaves were incubated in a growth chamber (80 to 90% relative humidity; 50 to 60 klx/m2 light intensity with a 12-h photoperiod). After 5 days, leaf spots similar to the original symptoms developed on all inoculated leaves and A. alternata was consistently reisolated from symptomatic leaf tissues on PDA. Control leaflets inoculated with sterile water remained asymptomatic. The experiment was performed three times. To our knowledge, this is the first report of A. alternata on B. chinense from China. References: (1) A. Belisario et al. Plant Dis. 83:696, 1999. (2) C. Sui et al. Plant Dis. 93:844, 2009.

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

Plant Disease ◽  
2013 ◽  
Vol 97 (6) ◽  
pp. 845-845 ◽  
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.

scholarly journals First Report of Leaf Spot Disease on Dictamnus dasycarpus Caused by Phoma dictamnicola in China

Plant Disease ◽  
2011 ◽  
Vol 95 (6) ◽  
pp. 771-771 ◽  
Author(s):  
Q. Bai ◽  
Y. Xie ◽  
J. Gao ◽  
B. Lu ◽  
W. Wang ◽  
...  
Keyword(s):  
Its Region ◽  
Leaf Spot Disease ◽  
Conidial Suspension ◽  
Sterile Water ◽  
Nuclear Rdna ◽  
First Report ◽  
Leaf Spots ◽  
Plastic Bags ◽  
Pathogenicity Tests ◽  
Herbal Plant

Fraxinella, Dictamnus dasycarpus Turcz (Rutaceae), is a perennial herbal plant and mainly distributed in Eurasia and North America. It is often used to treat jaundice, cough, rheumatism, and other diseases and is extensively cultivated in the northeast and northwest of China (3). In June 2009, a severe foliar disease was observed on D. dasycarpus in medicinal plantations in Antu, China. The disease occurred on 100% of the plants and at least 25% of the surface was affected. In the early stages of disease development, symptoms were visible on the top and bottom of infected leaves as small brown spots. Subsequently, these spots became elliptical to irregularly shaped, with beige or grayish white centers and dark brown margins. Within the spots, numerous, dark brown or black, subglobose or ostiolate pycnidia measuring 152 to 367 μm in diameter were observed. Fungal isolates were obtained from the infected leaves on potato dextrose agar (PDA) medium, with conidia that were aseptate or one-septate and ellipsoidal or reniform, measuring approximately 4.7 to 12.6 × 2.1 to 4.5 μm. On the basis of these characteristics, the fungus was identified as a Phoma sp. Four well-sporulating isolates, designated as DdPh-1, DdPh-2, DdPh-3, and DdPh-4, were selected for further studies. The morphological and cultural characteristics of these four isolates were studied as described by Boerema et al. and the fungus was identified as Phoma dictamnicola Boerema et al. (1). The internal transcribed spacer (ITS) region of the nuclear rDNA was amplified and sequenced using primers ITS4/ITS5 (2). All four of the ITS sequences were identical (GenBank Accession No. FR681861) and were 99% identical to P. dictamnicola strains CBS507.91 (Accession No. GU237877) and KACC42445 (Accession No. EF600960). Pathogenicity tests were performed by spraying the leaves of healthy D. dasycarpus plants with a conidial suspension (1 × 106 conidia/ml). Five plants were inoculated with each isolate (DdPh-1, DdPh-2, DdPh-3, and DdPh-4) and five plants were mock inoculated with sterile water. The plants were covered with plastic bags and kept in a greenhouse at 20 to 25° for 72 h. After 9 to 13 days, all inoculated plants showed characteristic symptoms as previously described, while the control plants remained healthy. The fungus was reisolated from the leaf spots of inoculated plants. Currently, the economic importance of this disease is limited, but it may become a more significant problem in production of D. dasycarpus with the cultivation area increasing. The fungus was found in the Netherlands and Korea, but to our knowledge, this is the first report of P. dictamnicola on D. dasycarpus in China. References: (1) G. H. Boerema et al. Phoma Identificatión Manual: Differentiation of Specific and Infra-Specific Taxa in Culture. CABI Publishing. Wallingford, U.K., 2004. (2) D. E. L. Cooke et al. Mycol. Res. 101:667, 1997. (3) S. S. Jiang et al. Biosci. Biotechnol. Biochem. 72:660, 2008.

scholarly journals First Report of Anthracnose Caused by Colletotrichum gloeosporioides on Ramie in China

Plant Disease ◽  
2010 ◽  
Vol 94 (12) ◽  
pp. 1508-1508 ◽  
Author(s):  
X. X. Wang ◽  
B. Wang ◽  
J. L. Liu ◽  
J. Chen ◽  
X. P. Cui ◽  
...  
Keyword(s):  
Colletotrichum Gloeosporioides ◽  
Morphological Characteristics ◽  
The Philippines ◽  
Herbaceous Plant ◽  
Commonwealth Mycological Institute ◽  
First Report ◽  
Perennial Herbaceous Plant ◽  
Rdna Its ◽  
Pathogenicity Tests ◽  
And Control

Ramie (Boehmeria nivea), usually called “China grass”, is a perennial herbaceous plant belonging to the family Urticaceae with recognized importance in the production of fibers. It is mainly planted in China and other Asian countries including the Philippines, India, South Korea, and Thailand. From June 2007 to September 2010, typical anthracnose symptoms were observed in cultivated ramie fields in HuBei, HuNan, JiangXi, and SiChuan provinces, China, with the diseased area estimated to be more than 10,000 ha. Ramie yield was reduced by 20% on average with up to 55% yield losses in some fields. Lesions were initially small, scattered, round, and gray with brown margin on leaves. As the disease progressed, irregular spots developed and expanded until the leaves withered. Initial lesions on stems were fusiform and expanded, causing the stem to break. Finally, the fibers ruptured. Five isolates (CS-1, CS-2, CS-3, CS-4, and CS-5) were used to evaluate cultural and morphological characteristics of the pathogen. On potato dextrose agar, all isolations initially developed white colonies with orange conidial mass and the colonies turned to gray or brown after 5 days of incubation. Twenty conidia and fifteen setae were measured. Conidia were single celled, colorless, straight, oval, obtuse at both ends, and 11 to 18 × 3 to 6 μm with an average of 14.89 × 4.32 μm. Conidiophores were dense and 11 to 22 × 4 to 5 μm with an average of 15.82 × 4.43 μm. Setae were few, dark brown, one to two septa, and 62 to 71 × 4 to 5 μm with an average of 65.13 × 4.46 μm. The pathogen was identified as Colletotrichum gloeosporioides on the basis of descriptions in Bailey and Jeger (1). Genomic DNA was extracted from the five isolates and sequences of rDNA-ITS with primers ITS1 and ITS4 were obtained (GenBank Accession Nos. GQ120479–GQ120483). Comparison with sequences in GenBank showed 99 to 100% similarity with C. gloeosporioides (Accession Nos. FJ515005, FJ459930, and HM016798). Pathogenicity tests were performed with the five isolates in the laboratory by spraying conidial suspensions (1 × 106 conidia/ml) onto upper and lower surfaces of 10 leaves of 10-day-old, 30-cm high plants. There were three replicate plants for each isolate. The inoculated plants were incubated with a 12-h photoperiod at 25 to 28°C and 90% relative humidity in an artificial climate chamber. Three days after inoculation, brown spots were observed on all inoculated leaves, but no symptoms were seen on water-treated control plants. Koch's postulates were fulfilled by reisolation of C. gloeosporioides from diseased leaves. Though in the revision of Colletotrichum by von Arx (4) and Sutton (3), C. boehmeriae, named based on host specificity, was cancelled, C. boehmeriae was regarded as a pathogen of ramie by some Chinese researchers (2). To our knowledge, this is the first report of C. gloeosporioides causing anthracnose of ramie in China. References: (1) J. A. Bailey and M. J. Jeger. Colletotrichum: Biology, Pathology and Control. CAB International, Wallingford, UK, 1992. (2) R. M. Li and H. G. Ma. J. Plant Prot. 20:83, 1993. (3) B. C. Sutton. Page 523 in: The Coelomycetes: Fungi Imperfecti with Pycnidia, Acervuli and Stromata. Commonwealth Mycological Institute, London, 1980. (4) J. A. von Arx. Phytopathol. Z. 29:413, 1957.

scholarly journals First Report of Anthracnose of Cagaita Caused by Colletotrichum gloeosporioides in Brazil

Plant Disease ◽  
2001 ◽  
Vol 85 (7) ◽  
pp. 801-801 ◽  
Author(s):  
J. R. N. Anjos ◽  
M. J. A. Charchar
Keyword(s):  
Colletotrichum Gloeosporioides ◽  
Federal District ◽  
Potato Dextrose Agar ◽  
First Report ◽  
Central Brazil ◽  
Leaf Spots ◽  
Sterile Needle ◽  
Pathogenicity Tests ◽  
Eugenia Dysenterica ◽  
Needle Control

Cagaita (Eugenia dysenterica Mart. Ex DC.), family Myrtaceae, is an important wild perennial fruit crop in Central Brazil (1). Anthracnose symptoms were observed on cagaita leaves in a field in Brasília, Federal District (S 15° 36′ 16″ W 47° 42′ 42″), in August 2000. A fungus was consistently isolated from infected leaves and grown on potato dextrose agar (PDA) and its identification was made by P. F. Cannon of CABI Bioscience as Colletotrichum gloeosporioides (Penzig) Penzig & Sacc. (IMI 384184). Pathogenicity tests were performed on 16 cagaita seedlings by placing mycelial PDA plugs on leaves previously wounded with a sterile needle. Control plants were inoculated with plugs without mycelia. After inoculations, the plants were placed in a dew chamber maintained at 25°C for 72 h and later transferred to the greenhouse. Necrotic leaf spots developed on 100% of the inoculated plants 4 days later. Koch's postulates were fulfilled by consistently reisolating C. gloeosporioides from inoculated plants. Control plants remained symptomless. Inoculations were repeated twice with the same results. To the authors' knowledge, this is the first report of anthracnose caused by C. gloeosporioides of cagaita in Brazil. Reference: (1) S. P. Almeida et al. 1998. Pages 182–186 in: Cerrado: espécies vegetais úteis. Embrapa Cerrados.

scholarly journals First Report of Black Spot Caused by Colletotrichum gloeosporioides on Paper Mulberry in China

Plant Disease ◽  
2011 ◽  
Vol 95 (7) ◽  
pp. 880-880 ◽  
Author(s):  
J. Yan ◽  
P. S. Wu ◽  
H. Z. Du ◽  
Q. E. Zhang
Keyword(s):  
Colletotrichum Gloeosporioides ◽  
Black Spot ◽  
Pathogenic Fungi ◽  
Conidial Suspension ◽  
Stem Cuttings ◽  
Sterile Water ◽  
First Report ◽  
Forest Park ◽  
Plastic Bags ◽  
Black Spots

Paper mulberry, Broussonetia papyrifera (L.) Venten. (family Moraceae), is a fast-growing tree with luxuriant branches and leaves. Because of strong adaptability and tolerance to unfavorable environmental conditions, it is an important tree species for shade or shelter and reforestation in mined areas and on hillsides. During the summer of 2010, brown-to-black spots were observed on leaves of paper mulberry in Baiwangshan Forest Park in Beijing, China. Early symptoms were round or elliptic, light brown, small lesions that later extended to round or irregular spots (4 to 6 × 4 to 8 mm) that were dark brown or black in the center with brown or light brown margins. Several dozen spots were found on severely infected leaves. Leaf tissues (2 × 2 mm), cut from the margins of lesions, were surface disinfected in 0.5% NaOCl solution for 3 min, rinsed three times with sterile water, plated on potato dextrose agar (PDA) and incubated at 25°C with a 12-h light and 12-h dark period. Numerous waxy subepidermal acervuli with setae were observed after 3 days. Acervuli were brown or black, round or elongate, and 100 to 250 μm in diameter. Setae were dark brown, erect straight or slightly curved, and 60 to 74 × 4 to 8 μm with one to two septa. Conidiophores were hyaline or light brown, short with no branches, and cylindrical with dimensions of 12 to 21 × 4 to 5 μm. Conidia were 11 to 21 × 3 to 6 μm, hyaline, aseptate, and cylindrical. Mycelia on PDA were off white-to-dark gray on the reverse side of the colony. Six isolates (BP21-1 to BP21-6) were obtained from different infected leaves and identified as Colletotrichum gloeosporioides (Penz.) Penz. & Sacc. (teleomorph Glomerella cingulata (Stonem.) Spaulding & Schrenk) on the basis of reverse colony color, dimensions and colors of acervuli, conidiophores, and conidia (3). ITS1-5.8S-ITS2 rDNA sequence analysis was performed on all six isolates. The resultant sequences were identical (GenBank Accession No. HQ 654780) and revealed 99% similarity (100% coverage) with C. gloeosporioides isolates in the GenBank (Accession Nos. EU371022.1 and AY376532.1) (2). Pathogenicity was demonstrated using six potted 3-month-old paper mulberry trees. Isolate BP21-2 was grown on PDA for 14 days and conidia were harvested to prepare a suspension of 106 conidia/ml. Three plants were sprayed with the conidial suspension and three were sprayed with sterile water. All trees were covered with plastic bags for 24 h to maintain high humidity and incubated at 25°C for 6 days. All conidia-inoculated trees showed identical symptoms as the infected leaves in the park, while the control trees remained symptom free. Reisolation of the fungus confirmed that the causal agent was C. gloeosporioides. C. gloeosporioides is distributed worldwide causing anthracnose on a wide variety of plants including members of mulberry family Moraceae, e.g., mortality of stem cuttings and death of saplings on mulberry (Morus alba L.) in India (1). To our knowledge, this is the first report of C. gloeosporioides causing black spots on paper mulberry in China. References: (1) V. P. Gupta et al. Indian Phytopathol. 50:402, 1997. (2) K. D. Hyde et al. Fungal Divers. 39:147, 2009. (3) J. E. M. Mordue. No. 315 in: Descriptions of Pathogenic Fungi and Bacteria. CMI. Kew, Surrey, UK, 1971.

scholarly journals First Report of Leaf Spot on Japanese Plum Caused by an Alternaria sp. in Korea

Plant Disease ◽  
2005 ◽  
Vol 89 (3) ◽  
pp. 343-343 ◽  
Author(s):  
Youngjun Kim ◽  
Hyang Burm Lee ◽  
Seung Hun Yu
Keyword(s):  
Leaf Spot ◽  
Morphological Characteristics ◽  
The United States ◽  
Conidial Suspension ◽  
First Report ◽  
Japanese Plum ◽  
Leaf Spots ◽  
Causal Fungus ◽  
Pathogenicity Tests ◽  
Alternaria Sp

Japanese plum (Prunus salicina Lindley) is a deciduous tree in the family Rosaceae. In Korea, this plant is widely distributed in orchards as an important stone fruit as well as in gardens as an ornamental tree because of their abundant white blossoms. Every September to November since 2001, leaf spots were observed on Japanese plum in a garden in Cheongyang, Chungnam District, Korea. Early symptoms consisted of small, brown spots that were 2 to 5 mm in diameter. Later, the leaf lesions became circular or irregular, dark brown, expanded to 15 mm in diameter, and resulted in discoloration with necrosis on twisted leaves that was followed by defoliation. In November, older lesions sometimes appeared blackish brown as sporulation occurred on the lesions. The causal fungus was isolated from diseased leaves and cultured on potato dextrose agar. A culture has been placed in the CABI Herbarium (IMI Accession No. 387139). Conidial dimension averaged 34 × 12 μm. On the basis of morphological characteristics of conidia and conidiophores, the causal fungus was identified as a small-spored species of Alternaria as described by E. G. Simmons (1). Pathogenicity tests were conducted by inoculating slightly wounded and nonwounded leaves with a conidial suspension adjusted to 1 × 106 conidia/ml. Four leaves per each experiment were either wounded or not and inoculated with a spore suspension. The eight leaves were placed in a moist chamber at 25°C. After 6 to 10 days, small brown spots appeared on 87% of the wounded and nonwounded leaves. Control leaves sprayed with distilled water did not develop any symptoms. The causal fungus was consistently reisolated from the leaf spots. Results from pathogenicity tests were similar in a repeated test. It is possible that small-spored Alternaria spp. isolates are host specific (2). Eight Alternaria spp., including A. alternata, A. tenuis, A. tenuissima, and A. citri, have been found to cause black spot on fifteen Prunus spp. in China, Japan, Hong Kong, Libya, Mexico, Australia, and the United States (2). Further studies on the host-specific toxin production, geographical distribution, and host ranges for the species of Alternaria isolated from Japanese plum are in progress. To our knowledge, this is the first report of leaf spot on Japanese plum (P. salicina) caused by a small-spored Alternaria sp. in Korea. References: (1) E. G. Simmons. Mycotaxon 55:79, 1995. (2) K. Inoue and H. Nasu. J. Gen. Plant Pathol. 66:18, 2002.

scholarly journals First Report of Peanut Pod Rot Caused by Neocosmospora vasinfecta in Northern China

Plant Disease ◽  
2012 ◽  
Vol 96 (3) ◽  
pp. 455-455 ◽  
Author(s):  
W. M. Sun ◽  
L. N. Feng ◽  
W. Guo ◽  
D. Q. Liu ◽  
Y. N. Li ◽  
...  
Keyword(s):  
Morphological Characteristics ◽  
Its Region ◽  
Northern China ◽  
Conidial Suspension ◽  
Sterile Water ◽  
Emerg Infect ◽  
First Report ◽  
Black Spots ◽  
Pathogenicity Tests ◽  
Average Size

From 2006 to 2010, peanut (Arachis hypogaea) pod rot became more prevalent in northern China, especially in the Sha River drainage area. The incidence of pod rot ranged from 30 to 100%. Typical symptoms were black rot of the pods, but no obvious morphological abnormality of the aboveground parts of infected plants was observed. Brown or black spots appeared on many pods when initially infected and then all peanut pods became black and rotten. The same fungus was isolated from 54 surface-disinfested lesions (85.2% of all lesions) on potato dextrose agar (PDA) media. One isolate, designated as HBXLb, was chosen for further characterization. In culture, both anamorph and teleomorph were present. Mycelia of the fungus grew quickly (colonies were 3.2 cm in diameter in 3 days) and became white and floccose on PDA at 28°C. The hyaline, elongated-to-cylindrical conidia aggregated on the slimy heads of conidiogenous cells that developed on undifferentiated hyphae after incubation for 3 to 4 days. Conidial sizes varied from 5 to 10 × 1.5 to 3 μm (n = 50) and were mostly single celled. Some conidia appeared slightly curved. The morphology was consistent with Acremonium spp. Numerous ascomata (perithecia) formed within 10 to 14 days when incubated at 28°C under light and dark conditions. Perithecia were orange-brown, strawberry shaped (300 to 400 μm in diameter), and ostiolate on the top. Cylindrical asci, with an average size of 90 to 110 × 7.5 to 9 μm, were present inside the ascomata with each containing eight ascospores in a row. The ascospores were brownish, spherical to ellipsoidal, and 10 to 15 × 8 to 12 μm. The cultural and morphological characteristics of isolate HBXLb matched the description of N. vasinfecta (2). The internal transcribed spacer (ITS) region of rDNA was amplified by the primer pairs ITS4/ITS5. A 525-bp amplicon (ITS4-5.8s-ITS5) was obtained and sequenced (GenBank Accession No. HM461901). The ITS sequence was a 100% match to N. vasinfecta strain N-JXLN01 (GenBank Accession No. GU213063) by BLASTn in GenBank. Pathogenicity tests were conducted on detached pods of peanut cultivar Jihua 4. Forty surface-disinfested peanut pods were soaked in a conidial suspension (105 conidia per ml) for 2 min and 40 pods were soaked in sterile water as a control. Then all peanut pods were maintained in moist petri dishes under darkness for 14 days at 28°C. Brown or black spots appeared on all pods inoculated with the fungus within 10 days, while the controls remained healthy. Symptoms were similar to those originally observed in the field, and N. vasinfecta could be reisolated from all infected pods. This fungus previously has been reported as the pathogen of foot rot of peanut in South Africa (1), Taiwan (4), and Australia (3). To our knowledge, this is the first report of peanut pod rot caused by N. vasinfecta in China. References: (1) S. W. Baard et al. Phytophylactica 17:49, 1985. (2) O. A. Cornely et al. Emerg. Infect. Dis. 7:149, 2001. (3) M. F. Fuhlbohm et al. Australas. Plant Dis. Notes 2:3, 2007. (4) J. W. Huang et al. Plant Pathol. Bull. 1:203, 1992.

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