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

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.

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First Report of Colletotrichum gloeosporioides on Russian-thistle

Plant Disease ◽

10.1094/pdis.1998.82.12.1405b ◽

1998 ◽

Vol 82 (12) ◽

pp. 1405-1405 ◽

Cited By ~ 6

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.

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First Report of Stem Blight of Eleocharis dulcis Caused by Phoma bellidis in China

Plant Disease ◽

10.1094/pdis-05-11-0438 ◽

2011 ◽

Vol 95 (9) ◽

pp. 1190-1190 ◽

Cited By ~ 3

Author(s):

R. Lv ◽

L. Zheng ◽

Z. Zhu ◽

L. Pan ◽

J. Huang ◽

...

Keyword(s):

Morphological Characteristics ◽

Tween 20 ◽

Herbaceous Plant ◽

Malt Extract ◽

First Report ◽

Perennial Herbaceous Plant ◽

Mercuric Chloride Solution ◽

Pathogenicity Tests ◽

Crop Area ◽

Multiple Stems

Eleocharis dulcis is a perennial herbaceous plant in the family Cyperaceae, which is native to China and India where it grows well in moist-to-wet soils. It is commonly used as a fruit or a vegetable. From August 2009 to December 2010, symptoms were observed on E. dulcis stems in Tuanfeng County, Hubei, China, with the crop area affected estimated to be more than 1,300 ha per year. Corm yield was reduced by 20% on average with as much as 60% yield losses in some fields. Lesions were initially small, red-brown, and oval or circular that enlarged to produce apical necrosis and extending until the stems withered, usually within 2 months. To obtain isolates, diseased tissue was disinfested for 1 min in 0.1% mercuric chloride solution, rinsed with sterilized water, and plated on potato dextrose agar. Isolates with similar morphological characteristics were consistently recovered. Three isolates, CTF-3, CTF-10, and CTF-11, were used to further evaluate characteristics of the pathogen. After 7 days, white colonies were 76 to 80 mm across on oatmeal agar (OA) with sparse aerial hyphae and a slight salmon color in the conidial masses. Pycnidia produced on OA were globose to subglobose, usually with one slightly ostiolar papilla, olivaceous to olivaceous black, and 93 to 245 μm in diameter. Conidia were hyaline, unicellular, ellipsoidal, mostly with two polar guttules, and 3.6 to 6.2 × 2.0 to 3.3 μm. Chlamydospores were absent. Growth of the isolates on malt extract agar (MEA) was slower than on OA, and the colony diameters at 7 days were 60 to 65 mm. The reactions with 1M NaOH were both positive on OA and MEA where the cultures initially changed to yellow green and gradually turned to red. The pathogen was identified as Phoma bellidis Neerg. based on descriptions in Boerema et al. (2). Pathogenicity tests were performed with the three isolates in the laboratory by spraying conidial suspensions (1 × 106 conidia/ml) containing 0.1% Tween 20 until runoff (30 ml per plant) onto stem surfaces of 50-day-old, 60 cm tall plants. For each isolate, there were 50 stems from five replicate plants that had multiple stems per plant. Control plants were treated with sterilized water containing 0.1% Tween 20 only. Plants were incubated with a 16-h photoperiod at 28°C and 90% relative humidity in an artificial climate chamber. Five days after inoculation, typical red-brown spots were observed on all inoculated stems but no symptoms were seen on water-treated control plants. Koch's postulates were fulfilled by reisolation of P. bellidis from diseased stems. The pathogenicity tests were repeated twice more with the same results. P. bellidis has only been reported previously on Bellis spp. from England, Denmark, Italy, the Netherlands, and Switzerland (1,2). Furthermore, there are only a few fungal diseases known to be associated with E. dulcis, and none so far that involve species of Phoma (3,4). To our knowledge, this is the first report of P. bellidis infecting E. dulcis worldwide. References: (1) M. M. Aveskamp et al. Stud. Mycol. 65:27, 2010. (2) G. H. Boerema et al. Phoma Identification Manual: Differentiation of Specific and Infra-Specific Taxa in Culture. CABI Publishing, Wallingford, UK, 2004. (3) P. L. Lentz. Am. Midl. Nat. 67:184, 1962. (4) L. Pan et al. J. Changjiang Vegetables (in Chinese) 14:10, 2010.

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First Report of Leaf Spot Disease Caused by Colletotrichum gloeosporioides on Chinese Bean Tree in China

Plant Disease ◽

10.1094/pdis-03-12-0261-pdn ◽

2013 ◽

Vol 97 (1) ◽

pp. 138-138 ◽

Cited By ~ 1

Author(s):

B. Z. Fu ◽

M. Yang ◽

G. Y. Li ◽

J. R. Wu ◽

J. Z. Zhang ◽

...

Keyword(s):

Leaf Spot ◽

Colletotrichum Gloeosporioides ◽

Disease Incidence ◽

Phylogenetic Analyses ◽

Morphological Characteristics ◽

Leaf Spot Disease ◽

First Report ◽

Spot Disease ◽

Rdna Its ◽

Its Sequence Analysis

Chinese bean tree, Catalpa fargesii f. duciouxii (Dode) Gilmour, is an ornamental arbor plant. Its roots, leaves, and flowers have long been used for medicinal purposes in China. During July 2010, severe outbreaks of leaf spot disease on this plant occurred in Kunming, Yunnan Province. The disease incidence was greater than 90%. The symptoms on leaves began as dark brown lesions surrounded by chlorotic halos, and later became larger, round or irregular spots with gray to off-white centers surrounded by dark brown margins. Leaf tissues (3 × 3 mm), cut from the margins of lesions, were surface disinfected in 0.1% HgCl2 solution for 3 min, rinsed three times in sterile water, plated on potato dextrose agar (PDA), and incubated at 28°C. The same fungus was consistently isolated from the diseased leaves. Colonies of white-to-dark gray mycelia formed on PDA, and were slightly brown on the underside of the colony. The hyphae were achromatic, branching, septate, and 4.59 (±1.38) μm in diameter on average. Perithecia were brown to black, globose in shape, and 275.9 to 379.3 × 245.3 to 344.8 μm. Asci that formed after 3 to 4 weeks in culture were eight-spored, clavate to cylindrical. The ascospores were fusiform, slightly curved, unicellular and hyaline, and 13.05 to 24.03 × 10.68 to 16.02 μm. PCR amplification was carried out by utilizing universal rDNA-ITS primer pair ITS4/ITS5 (2). Sequencing of the PCR products of DQ1 (GenBank Accession No. JN165746) revealed 99% similarity (100% coverage) with Colletotrichum gloeosporioides isolates (GenBank Accession No. FJ456938.1, No. EU326190.1, No. DQ682572.1, and No. AY423474.1). Phylogenetic analyses (MEGA 4.1) using the neighbor-joining (NJ) algorithm placed the isolate in a well-supported cluster (>90% bootstrap value based on 1,000 replicates) with other C. gloeosporioides isolates. The pathogen was identified as C. gloeosporioides (Penz.) Penz. & Sacc. (teleomorph Glomerella cingulata (Stoneman) Spauld & H. Schrenk) based on the morphological characteristics and rDNA-ITS sequence analysis (1). To confirm pathogenicity, Koch's postulates were performed on detached leaves of C. fargesii f. duciouxii, inoculated with a solution of 1.0 × 106 conidia per ml. Symptoms similar to the original ones started to appear after 10 days, while untreated leaves remained healthy. The inoculation assay used three leaves for untreated and six leaves for treated. The experiments were repeated once. C. gloeosporioides was consistently reisolated from the diseased tissue. C. gloeosporioides is distributed worldwide causing anthracnose on a wide variety of plants (3). To the best of our knowledge, this is the first report of C. gloeosporioides causing leaf spots on C. fargesii f. duciouxii in China. References: (1) B. C. Sutton. Page 1 in: Colletotrichum: Biology, Pathology and Control. CAB International. Wallingford, UK, 1992. (2) T. J. White et al. Page 315 in: PCR Protocols: A Guide to Methods and Applications. Academic Press, San Diego, 1990. (3) J. Yan et al. Plant Dis. 95:880, 2011.

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First Report of Root Rot on Atractylodes macrocephala (Largehead Atractylodes Rhizome) Caused by Ceratobasidium sp. in China

Plant Disease ◽

10.1094/pdis-05-12-0467-pdn ◽

2013 ◽

Vol 97 (1) ◽

pp. 139-139 ◽

Cited By ~ 4

Author(s):

J. M. You ◽

X. M. Lin ◽

J. Guo ◽

M. D. Zhang ◽

C. L. Liao ◽

...

Keyword(s):

Root Rot ◽

Morphological Characteristics ◽

White Mold ◽

Herbaceous Plant ◽

First Report ◽

Perennial Herbaceous Plant ◽

Mercuric Chloride Solution ◽

Whole Plant ◽

Atractylodes Macrocephala ◽

Increasing Temperature

Atractylodes macrocephala is a perennial herbaceous plant (family Asteraceae) native to China. The biennial root, Largehead Atractylodes Rhizome (LAR), is the most commonly used Chinese herbal medicine to prevent early pregnancy loss due to miscarriage. From summer 2010 to spring 2012, symptoms of root rot were observed on LAR in Xianfeng county, Enshi city, Hubei Province, China. White mold on the root of LAR could be observed at an early growth stage in the field and the white mold spread over the entire plant after 10 days, which differs from root rot of LAR caused by Fusarium oxysporum and Rhizoctonia solani, neither of which are characterized as having mycelium spreading over the whole plant (4). Where root rot symptoms were present, rhizome yield was reduced by 15% on average, with up to 40% yield loss in some fields. Under humid conditions in mid-June, the disease in the field spread quickly and the rhizomes of LAR were completely rotted. After rainfall and increasing temperature from 16 to 35°C, white mycelium appeared and plants withered within a few weeks. In April 2011 and 2012, a fungus was consistently recovered from symptomatic rhizome samples after they were surface sterilized with 0.1% mercuric chloride solution and plated onto potato dextrose agar (PDA). Pale gray colonies with short aerial mycelia and brown sclerotia formed on PDA after 7 days incubation at 28°C. Binucleate cells were observed using light microscopy and the characteristics were matched with morphological characteristics of a Ceratobasidium sp (3). Genomic DNA of the culture was extracted, and the rDNA-internal transcribed spacer sequence (GenBank Accession No. JQ926741) showed 99% identity to Ceratobasidium sp (GenBank No. H269825.1). Mycelial plugs of the culture taken from PDA were inoculated onto 40 rhizomes of 1-year-old seedlings and plants were incubated with a 16-h photoperiod at 28°C and 90% relative humidity in an artificial climate chamber where they developed typical disease symptoms after 2 days. Ten rhizomes of 1-year-old seedlings and were treated with PDA plugs only. All seedlings inoculated with the pathogen were withered and the rhizomes were completely covered with gray mycelium 2 days after inoculation, which was similar to the symptoms observed in the field. After 7 days, the symptoms were more severe than those observed in the field, with seedlings rotted completely. The main stalk of all inoculated plants was covered with gray mycelia in 4 days, and the stalk became withered, which was similar to the symptoms observed in the field. No symptoms were observed on control seedlings and plants. Koch's postulates were fulfilled by successful reisolation of Ceratobasidium sp. from diseased seedlings. The pathogenicity tests were carried out twice. Ceratobasidium sp. has been reported to cause root rot of canola in Washington (2). It has also been observed on Rehmannia in China (1). To our knowledge, this is the first report of Ceratobasidium sp. causing root rot on LAR. References: (1) B. B. Chen et al. Chin. J. Chin. Material Medica (In Chinese) 9:1137, 2011. (2) K. L. Schroeder et al. Plant Dis. 96:591, 2012. (3) B. Sneh et al. Page 39 in: Identification of Rhizoctonia Species. The American Phytopathological Society, 1991. (4) S. X. Zang et al. J. Agric. Univ. Hebei (In Chinese) 28:73, 2005.

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First Report of Leaf Spot Caused by Corynespora cassiicola on Baphicacanthus cusia in China

Plant Disease ◽

10.1094/pdis-10-12-0921-pdn ◽

2013 ◽

Vol 97 (5) ◽

pp. 690-690

Author(s):

Q.-L. Li ◽

S.-P. Huang ◽

T.-X. Guo ◽

Z.-B. Pan ◽

J.-Y. Mo ◽

...

Keyword(s):

Leaf Spot ◽

Ipomoea Batatas ◽

Its Region ◽

Tween 20 ◽

Herbaceous Plant ◽

Commonwealth Mycological Institute ◽

Corynespora Cassiicola ◽

Single Spore ◽

First Report ◽

Perennial Herbaceous Plant

Baphicacanthus cusia is a perennial herbaceous plant in the family Acanthaceae that is native to China, where it grows in warm temperate mountainous or hilly regions. It is commonly used as a Chinese herbal medicine. In March 2012, symptoms of leaf spot were observed on leaves of B. cusia in Long'an County, Guangxi, China, where this plant is extensively cultivated. Symptoms were initially small brown dots which developed into irregular to circular leaf spots. These spots enlarged and overlapped, extending until the 7- to 9-cm-long and 3- to 4-cm-wide leaves withered entirely, mostly within 2 months. On potato dextrose agar (PDA), the same fungus was cultured from 92% of 75 symptomatic leaf samples that had been surface sterilized in a 45-second dip in 0.1% mercuric chloride. Fungal structures were observed on diseased leaves: conidiophores (85 to 460 × 4 to 8 μm) were erect, brown, single or in clusters, and conidia (36 to 90 × 5 to 16 μm) were single or in chains of two to four, brown, cylindrical or obclavate, straight or slightly curved, with 3 to 18 pseudosepta and a conspicuous hilum. Three single-spore isolates were identified as Corynespora cassiicola (Berk & Curt.) Wei based on morphological and cultural characteristics (1). The rDNA internal transcribed spacer (ITS) region of one isolate, ZY-1, was sequenced (GenBank Accession No. JX908713), and it showed 100% identity to C. cassiicola, GenBank FJ852716, an isolate from Micronesia cultured from Ipomoea batatas (2). Pathogenicity tests were performed with each of the three isolates by spraying conidial suspensions (5 × 104 conidia/ml) containing 0.1% Tween 20 onto the surfaces of leaves of 60-day-old, 20-cm tall plants. For each isolate, 30 leaves from five replicate plants were treated. Control plants were treated with sterilized water containing 0.1% Tween 20. All plants were incubated for 36 h at 25°C and 90% relative humidity in an artificial climate chamber, and then moved into a greenhouse. Seven days after inoculation, dark brown spots typical of field symptoms 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. cassiicola from diseased leaves. To our knowledge, this is the first report of C. cassiicola infecting B. cusia worldwide. References: (1) M. B. Ellis. Dematiaceous Hyphomycetes. Commonwealth Mycological Institute: Kew, Surrey, England, 1971. (2) L. J. Dixon et al. Phytopathology 99:1015, 2009.

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First Report of Leaf Spot of Houttuynia cordata Caused by Alternaria alternata in China

Plant Disease ◽

10.1094/pdis-10-10-0724 ◽

2011 ◽

Vol 95 (3) ◽

pp. 359-359

Author(s):

L. Zheng ◽

R. Lv ◽

Q. Li ◽

J. Huang ◽

Y. Wang ◽

...

Keyword(s):

Alternaria Alternata ◽

Leaf Spot ◽

Southern China ◽

Sclerotium Rolfsii ◽

Tween 20 ◽

Herbaceous Plant ◽

Houttuynia Cordata ◽

First Report ◽

Perennial Herbaceous Plant ◽

Pathogenicity Tests

Houttuynia cordata is a perennial herbaceous plant (family Saururaceae) that is native to southern China, Japan, Korea, and Southeast Asia where it grows well in moist to wet soils. It is commonly used as a Chinese herbal medicine and as a vegetable. In North America and Europe it is also used as an ornamental. From September 2007 to November 2009, symptoms of leaf spot were found on H. cordata leaves in Dangyang County, Hubei, China, with the crop area affected estimated to be over 600 ha per year. Rhizome yield was reduced by 20% on average, with up to 70% yield losses in some fields during the autumn growing season. Lesions were initially small, brown, and oval or circular that developed into dark spots and sometimes formed target spots with white centers. These spots enlarged and overlapped, extending until the leaves withered entirely usually within 2 months. A fungus was consistently recovered from symptomatic leaf samples collected in October 2008 or 2009 with an average 90% isolation rate from ~60 leaf pieces that were surface sterilized with 0.1% mercuric chloride solution. Three isolates, HCDY-2, HCDY-3, and HCDY-4, were used to further evaluate characteristics of the pathogen. On potato dextrose agar, all cultures initially developed white colonies and the centers turned gray or brown after 4 days of incubation. Conidiophores were single or fasciculate, straight or knee curved, gray-brown with regular septa, and 42 to 61 × 4 to 5 μm. Conidia were obclavate or ovate, brown, and 26 to 38 × 12 to 20 μm with three to five transverse and one to three longitudinal or oblique septa. The tops of some conidia developed into secondary conidiophores, which were cylindrical, beige, and 5 to 17 × 3 to 5 μm. The pathogen was identified as Alternaria alternata based on descriptions in Simmons (3). Genomic DNA of HCDY-2 was extracted, and the rDNA-internal transcribed spacer sequence showed 99.6% identity to A. alternata (GenBank No. AY513941). Pathogenicity tests were performed with the three isolates by spraying conidial suspensions (1 × 106 conidia/ml) containing 0.1% Tween 20 onto upper and lower surfaces of leaves of 40-day-old 15-cm high plants. There were 20 leaves from five replicate plants for each isolate. Control plants were treated with sterilized water containing 0.1% Tween 20 only. All plants were incubated with a 16-h photoperiod at 25°C and 90% relative humidity in an artificial climate chamber. Five days after inoculation, typical 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 A. alternata from diseased leaves. The pathogenicity tests were carried out twice. A survey of the literature revealed only a few fungal diseases associated with H. cordata (1,2,4), including Phyllosticta houttuyniae, Pseudocercospora houttuyniae, Rhizoctonia solani, and Sclerotium rolfsii. Although A. alternata is a cosmopolitan plant pathogen, it has not been reported on any species in the four genera in Saururaceae (Anemopsis, Gymnotheca, Houttuynia, and Saururus) (3). To our knowledge, this is the first report of A. alternata infecting H. cordata worldwide. References: (1) Y. L. Guo and W. X. Zhao. Acta Mycol. Sin. 8:118, 1989. (2) K. Sawada. Spec. Publ. Taiwan Univ. 8:138, 1959. (3) E. G. Simmons. Alternaria: An Identification Manual. The American Phytopathological Society, St. Paul, MN, 2007. (4) Y. Wu et al. J. Changjiang Vegetables (In Chinese) 2:19, 2007.

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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 Anthracnose Caused by Colletotrichum gloeosporioides on Schefflera actinophylla in China

Plant Disease ◽

10.1094/pdis-12-12-1205-pdn ◽

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.

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First Report of Soft Rot on Dendrobium officinale caused by Epicoccum sorghinum in China

Plant Disease ◽

10.1094/pdis-04-21-0866-pdn ◽

2021 ◽

Author(s):

Caiyun Xiao ◽

Rongyu Li ◽

Xingchen Song ◽

Xujun Tian ◽

Qijun Zhao

Keyword(s):

Internal Transcribed Spacer ◽

Elongation Factor ◽

Morphological Characteristics ◽

Reference Value ◽

Soft Rot ◽

Dendrobium Officinale ◽

First Report ◽

Rdna Its ◽

And Control ◽

Internal Transcribed Spacer Rdna

In recent years, soft rot is one of the most serious diseases in the production of Dendrobium officinale. In this study, we took the diseased plants of Dendrobium officinale in Guizhou as samples, through Koch's rule and sequence analysis of rDNA internal transcribed spacer (rDNA-ITS), calmodulin (cmdA), the second largest subunit of RNA polymerase Ⅱ (RPB2), elongation factor EF-1 α and β-tubulin (β-Tub), it was determined that the pathogen of Dendrobium officinale soft rot was sorghum accessory cocci. This is our first report on the soft rot of Dendrobium officinale caused by Epicoccum sorghinum in China. The morphological characteristics of the pathogen shown in the study will have a certain reference value for the prevention and control of the soft rot of Dendrobium officinale in the future.

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First Report of Damping-Off of Rhodiola sachalinensis Caused by Rhizoctonia solani AG-4 HG-II in China

Plant Disease ◽

10.1094/pdis-07-11-0559 ◽

2012 ◽

Vol 96 (1) ◽

pp. 142-142 ◽

Cited By ~ 1

Author(s):

Q. Bai ◽

Y. Xie ◽

X. Wang ◽

Y. Li ◽

J. Gao ◽

...

Keyword(s):

Rhizoctonia Solani ◽

Morphological Characteristics ◽

Its Region ◽

Herbaceous Plant ◽

Protective Effects ◽

Damping Off ◽

First Report ◽

Rhodiola Sachalinensis ◽

Perennial Herbaceous Plant ◽

Safranin O

Rhodiola sachalinensis A. Bor (family Crassulaceae), a perennial herbaceous plant, is distributed mainly in the mountainous areas of China, Japan, Korea, and Russia. It is widely used as a traditional Chinese medicine with adaptogenic properties, cardiopulmonary protective effects, and central nervous system activities (3). Currently, it is extensively cultivated in northeastern China. In August 2010, widespread (>60% of plants were symptomatic) damping-off was observed in a seedling field in Linjiang, China. Leaves and stems near the ground were affected first, with dark lesions forming on the stem and the lowest leaves exhibiting wilt. The wilt spread rapidly over the entire plant with leaves becoming grayish brown and water soaked and then turned black and died. Root rot, defoliation, and damping-off were also observed. Six isolates with morphological characteristics of Rhizoctonia solani Kühn were isolated from symptomatic stems when plated on potato dextrose agar (PDA). Mycelium was branched at right angles with a septum near the branch and a slight constriction at the branch base. Fungal colonies were initially white, turned brown with age, and produced irregularly shaped, brown sclerotia after 8 days on PDA. Hyphal cells removed from cultures grown at 25°C on 2% water agar were determined to be multinucleate when stained with 1% safranin O and 3% KOH solution (1) and examined at ×400 magnification. The internal transcribed spacer (ITS) region of the nuclear rDNA was amplified by using the primers ITS4/ITS5 (2). The ITS sequences (715 bp) were identical in these six isolates (GenBank Accession No. FR878087) and had 100% sequence identity with R. solani AG-4 HG-II (GenBank Accession No. HQ629873) along with numerous other accessions from this AG subgroup. Pathogenicity tests were performed on healthy, potted seedlings of R. sachalinensis. Twenty plants were inoculated near the base of the stem with a 0.6-cm-diameter mycelial plug from 3-day-old PDA cultures for each isolate. Twenty plants inoculated with only PDA plugs served as controls. The plants were covered with plastic bags and kept in a greenhouse at 20 to 25°C for 72 h. All inoculated plants showed characteristic symptoms as previously observed in the seedling field 13 days after inoculation, while control plants remained healthy. R. solani AG-4 HG-II was reisolated from symptomatic tissues on inoculated plants. To our knowledge, this is the first report of R. solani AG-4 HG-II causing damping-off on R. sachalinensis in China. References: (1) R. J. Bandoni. Mycologia 71:873, 1979. (2) D. E. L. Cooke et al. Mycol. Res. 101:667, 1997. (3) T. F. Yan et al. Conserv. Genet. 4:213, 2003.

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