First Report of Colletotrichum gloeosporioides on Cyclamen persicum in Florida

Between March and April of 1996, an estimated 20% of the Cyclamen persicum Mill. grown in Florida were infected with Colletotrichum gloeosporioides (Penz.) Penz. & Sacc. in Penz. Symptoms included extensive lesions on flowers, stems, and leaves. Acervuli containing masses of spores and dark setae were observed within lesions. The most severe damage was observed on the cultivar Red Delight. Infected tissues were dipped into 0.26% sodium hypochlorite for 5 s, blotted dry, embedded in water agar, and incubated at 27 ± 1°C. Hyphal tips that grew from lesions were transferred to potato dextrose agar (PDA) and incubated under cool-white fluorescent lights. Developing colonies were gray and contained masses of orange conidia. Conidia were straight with rounded or bulbous ends and averaged 16.8 (SD 5.2) × 2.25 (SD 0.54) μm. Three isolates were selected to complete Koch's postulates. Conidia of each isolate were obtained from 3-day-old PDA cultures, and suspended in sterile, distilled water (SDW) to 104 conidia/ml. These suspensions were sprayed till runoff with hand sprayers onto C. persicum plants. Plants were incubated in plastic bags for 24 h at 27°C, then placed in a glasshouse. Within 3 days, lesions had developed on flowers; within 7 days, they were visible on stems and leaves. Lesion diameter varied from 2 to 5 mm; however, lesions soon coalesced, causing leaf, stem, and flower death. The fungus was reisolated from acervuli that developed on the flowers, stems, and leaves, following previously outlined procedures. Inoculation tests were repeated once. Symptoms did not appear on controls sprayed with SDW nor was the teleomorph stage of the pathogen observed.

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First Report of Colletotrichum gloeosporioides on Chinese Rose in Argentina

Plant Disease ◽

10.1094/pdis.2000.84.12.1345b ◽

2000 ◽

Vol 84 (12) ◽

pp. 1345-1345 ◽

Cited By ~ 1

Author(s):

M. C. Rivera ◽

E. R. Wright ◽

S. Carballo

Keyword(s):

Colletotrichum Gloeosporioides ◽

Buenos Aires ◽

Morphological Characteristics ◽

Disease Prevalence ◽

Potato Dextrose Agar ◽

Conidial Suspension ◽

First Report ◽

Hibiscus Rosa Sinensis ◽

Leaf Drop ◽

Stems And Leaves

Chinese rose (Hibiscus rosa-sinensis L.) is a shrub frequently planted in Argentina. In November 1999, dieback and anthracnose symptoms were detected on stems and leaves of plants cv. Hawaii cultivated in Buenos Aires. Disease prevalence was 50%. Pieces of infected tissues were surface-sterilized for 1 min in 2% NaOCl, plated on potato-dextrose agar and incubated at 24 ± 2°C. The isolate that was consistently recovered from diseased tissues was identified as Colletotrichum gloeosporioides (Penz.) Penz. and Sacc., based on morphological characteristics (1,2). Teleomorph stage was not observed. Inoculation for pathogenicity testing was carried out by spraying a conidial suspension (6.5 × 106 conidia per ml) on plants with previously punctured leaves and pruned stems. Inoculated plants with unwounded tissues, as well as noninoculated controls, were included. Five replications of each treatment were done. Plants were incubated in moist chambers at 24°C. Whitish areas of 0.3 to 0.5 cm diameter surrounded by a purple halo developed on all punctured leaves within 10 days. Stem blight and leaf drop were observed. The center of the lesions was covered by black acervuli 14 days after inoculation. Unwounded and noninoculated controls remained symptomless. The pathogen was reisolated from inoculated leaves, completing Koch's postulates. This is the first report of C. gloeosporioides causing disease on Chinese rose in Argentina. References: (1) J. A. Bailey and M. J. Jeger, eds. 1992. Colletotrichum. CAB International, Surrey, England. (2) B. C. Sutton. 1980. The Coelomycetes. CMI, Kew.

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First report of Colletotrichum siamense Causing Blossom Blight on Thai basil (Ocimum basilicum L.) in Malaysia

Plant Disease ◽

10.1094/pdis-06-20-1371-pdn ◽

2020 ◽

Author(s):

Siti Izera Ismail ◽

Nur Adlina Rahim ◽

Dzarifah Zulperi

Keyword(s):

Disease Incidence ◽

Its Region ◽

Ocimum Basilicum ◽

Distilled Water ◽

Single Spore ◽

First Report ◽

Plastic Bags ◽

Colletotrichum Siamense ◽

Primer Sets ◽

Acca Sellowiana

Thai basil (Ocimum basilicum L.) is widely cultivated in Malaysia and commonly used for culinary purposes. In March 2019, necrotic lesions were observed on the inflorescences of Thai basil plants with a disease incidence of 60% in Organic Edible Garden Unit, Faculty of Agriculture in the Serdang district (2°59'05.5"N 101°43'59.5"E) of Selangor province, Malaysia. Symptoms appeared as sudden, extensive brown spotting on the inflorescences of Thai basil that coalesced and rapidly expanded to cover the entire inflorescences. Diseased tissues (4×4 mm) were cut from the infected lesions, surface disinfected with 0.5% NaOCl for 1 min, rinsed three times with sterile distilled water, placed onto potato dextrose agar (PDA) plates and incubated at 25°C under 12-h photoperiod for 5 days. A total of 8 single-spore isolates were obtained from all sampled inflorescence tissues. The fungal colonies appeared white, turned grayish black with age and pale yellow on the reverse side. Conidia were one-celled, hyaline, subcylindrical with rounded end and 3 to 4 μm (width) and 13 to 15 μm (length) in size. For fungal identification to species level, genomic DNA of representative isolate (isolate C) was extracted using DNeasy Plant Mini Kit (Qiagen, USA). Internal transcribed spacer (ITS) region, calmodulin (CAL), actin (ACT), and chitin synthase-1 (CHS-1) were amplified using ITS5/ITS4 (White et al. 1990), CL1C/CL2C (Weir et al. 2012), ACT-512F/783R, and CHS-79F/CHS-345R primer sets (Carbone and Kohn 1999), respectively. A BLAST nucleotide search of ITS, CHS-1, CAL and ACT sequences showed 100% similarity to Colletotrichum siamense ex-type cultures strain C1315.2 (GenBank accession nos. ITS: JX010171 and CHS-1: JX009865) and isolate BPDI2 (CAL: FJ917505, ACT: FJ907423). The ITS, CHS-1, CAL and ACT sequences were deposited in GenBank as accession numbers MT571330, MW192791, MW192792 and MW140016. Pathogenicity was confirmed by spraying a spore suspension (1×106 spores/ml) of 7-day-old culture of isolate C onto 10 healthy inflorescences on five healthy Thai basil plants. Ten infloresences from an additional five control plants were only sprayed with sterile distilled water and the inoculated plants were covered with plastic bags for 2 days and maintained in a greenhouse at 28 ± 1°C, 98% relative humidity with a photoperiod of 12-h. Blossom blight symptoms resembling those observed in the field developed after 7 days on all inoculated inflorescences, while inflorescences on control plants remained asymptomatic. The experiment was repeated twice. C. siamense was successfully re-isolated from the infected inflorescences fulfilling Koch’s postulates. C. siamense has been reported causing blossom blight of Uraria in India (Srivastava et al. 2017), anthracnose on dragon fruit in India and fruits of Acca sellowiana in Brazil (Abirami et al. 2019; Fantinel et al. 2017). This pathogen can cause a serious threat to cultivation of Thai basil and there is currently no effective disease management strategy to control this disease. To our knowledge, this is the first report of blossom blight caused by C. siamense on Thai basil in Malaysia.

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First Report of the Pathogenicity of Colletotrichum gloeosporioides on Invasive Ferns, Lygodium microphyllum and L. japonicum, in Florida

Plant Disease ◽

10.1094/pdis.2003.87.1.101b ◽

2003 ◽

Vol 87 (1) ◽

pp. 101-101 ◽

Cited By ~ 2

Author(s):

K. A. Jones ◽

M. B. Rayamajhi ◽

P. D. Pratt ◽

T. K. Van

Keyword(s):

Colletotrichum Gloeosporioides ◽

First Record ◽

South Florida ◽

Growth Chamber ◽

Fluorescent Light ◽

Distilled Water ◽

Conidial Suspension ◽

Potted Plants ◽

Plastic Bags ◽

Fern Species

Lygodium microphyllum (Cav.) R.Br. (Old World climbing fern) and L. japonicum (Thunb.) Sw. (Japanese climbing fern), in the family Schizaeaceae, are among the most invasive weeds in Florida (1). L. microphyllum invades fresh water and moist habitats in south Florida, while L. japonicum has spread in relatively well-drained habitats from Texas to North Carolina and central Florida. Some potted plants of both Lygodium spp. grown in shadehouse as well as in full sunlight developed discolored spots on pinnules (foliage), which coalesced and resulted in browning and dieback of severely infected vines. Symptomatic foliage obtained from these plants was surface-sterilized by immersing in a 15% solution of commercial bleach for 90 s, followed by a series of four rinses with sterile deionized distilled water. Disks (4 mm in diameter) of pinnules were cut from the junction of discolored and healthy tissues and placed on potato dextrose agar (PDA). A fungus, Colletotrichum gloeosporioides (Penz.) Penz. & Sacc. was consistently isolated from these disks. Fungal colonies produced abundant conidia on PDA. Conidia were hyaline, straight, cylindrical, averaging 14.7 μm (range 12.5 to 17.5 μm) × 5.0 μm (range 3.8 to 7.5 μm), and similar to those described for C. gloeosporioides (2). To confirm the pathogenicity of C. gloeosporioides on L. microphyllum and L. japonicum, Koch's postulates were performed. A fungal isolate was grown on PDA for 3 weeks, after which 10 ml of sterile deionized distilled water was added to the culture and agitated to dislodge conidia. The conidial suspension was strained through three layers of cheesecloth to remove hyphal fragments, and its concentration was adjusted to 1.7 × 106 conidia/ml. Foliage of healthy L. microphyllum and L. japonicum plants grown in 500-ml containers was sprayed with the conidial suspension until runoff. Plants were covered with plastic bags whose inner sides were misted with water to maintain high humidity and placed in a growth chamber under 12 h of fluorescent light per day. Temperature and relative humidity in the chamber ranged from 26 to 29°C and 44 to 73%, respectively. Plastic bags were removed after 3 days, and plants were further incubated for 3 weeks in the same growth chamber. Control plants were sprayed with sterile water, covered with plastic bags, and exposed to the same temperature, light, and humidity regime as those of the fungus-inoculated plants. Small, discolored foliar spots appeared 3 days after fungus inoculation. These spots were similar to those observed on pinnules of potted plants that originated from shadehouse and outdoor environments. Within 3 weeks after inoculation, the foliage of L. japonicum developed abundant discolored spots that led to edge browning and wilting of the pinnules. L. microphyllum had similar but more severe symptoms, with plants suffering as much as 50% dieback. C. gloeosporioides was consistently reisolated from the symptomatic tissues of both fern species. No symptoms appeared on the water-inoculated plants. To our knowledge, this is the first record of C. gloeosporioides pathogenicity on L. microphyllum and L. japonicum. References: (1) R. W. Pemberton and A. P. Ferriter. Am. Fern J. 88:165, 1998. (2) B. C. Sutton. Colletotrichum: Biology, Pathology and Control. CAB International, Wallingford, Oxon, UK, 1992.

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First Report of Anthracnose of Salsola tragus Caused by Colletotrichum gloeosporioides in Russia

Plant Disease ◽

10.1094/pdis-92-9-1366b ◽

2008 ◽

Vol 92 (9) ◽

pp. 1366-1366 ◽

Cited By ~ 2

Author(s):

T. Kolomiets ◽

O. Skatenok ◽

A. Alexandrova ◽

Z. Mukhina ◽

T. Matveeva ◽

...

Keyword(s):

Colletotrichum Gloeosporioides ◽

Science Research ◽

Research Unit ◽

Internal Transcribed Spacers ◽

Conidial Suspension ◽

Voucher Specimen ◽

First Report ◽

Glucose Agar ◽

Stems And Leaves ◽

C 30

In October of 2006, dying Salsola tragus L. (Russian thistle, tumbleweed), family Chenopodiaceae, plants were found along the Azov Sea at Chushka, Russia. Approximately 40 plants in the area were diseased and almost 80% of these were dying. Plants were approximately 1 m tall × 0.5 m wide. Dying plants had irregular, necrotic lesions along the length of the stems. Leaves of these plants were also necrotic. Lesions on stems and leaves were dark brown and usually coalesced. Diseased stems were cut into 3- to 5-mm pieces, disinfested in 70% ethyl alcohol, and then placed onto the surface of potato glucose agar (PGA). Numerous, waxy, subepidermal acervuli with 110 μm long (mean) black setae were observed in all of the lesions after 2 to 3 days. Conidiophores were simple, short, and erect. Conidia were one-celled, hyaline, ovoid to oblong, falcate to straight, and measured 12.9 to 18.0 × 2.8 to 5.5 μm (mean 15.6 × 4.2 μm). Appressoria formed 24 h after placing conidia on a dialysis membrane over 20% V8 juice agar. Appressoria measured 4.0 to 13.9 × 2.4 to 8.8 μm (mean 7.0 × 5.2 μm). These characters conformed to the description of Colletotrichum gloeosporioides (Penz.) Penz. & Sacc. in Penz. (1). A voucher specimen was deposited with the U.S. National Fungus Collections, Beltsville, MD (BPI 878389). Nucleotide sequences for the internal transcribed spacers (ITS 1 and 2) were deposited in GenBank (Accession No. EU530697) and aligned with ITS sequences of two other isolates from S. tragus. There was 100% similarity to each isolate, one from Greece (Accession No. DQ344621) and one from Hungary (Accession No. EU805538). Axenic cultures on PGA were sent to the Foreign Disease-Weed Science Research Unit, USDA, ARS, Fort Detrick, MD for testing in quarantine. Conidia were harvested from 14-day-old cultures grown on 20% V8 juice agar, and healthy stems and leaves of 30-day-old plants of S. tragus (13 plants) were spray inoculated with an aqueous conidial suspension of 1.0 × 106 conidia/ml plus 0.1% v/v polysorbate 20. Another 13 control plants were sprayed with water and surfactant without conidia. Plants were placed in an environmental chamber at 100% humidity for 16 h in the dark at 25°C. After approximately 24 h, all plants were transferred to a greenhouse at 20 to 25°C, 30 to 50% relative humidity, and natural light augmented by 12-h light periods with 500 W sodium vapor lights. Lesions developed on stems of all inoculated plants after 7 days. After 14 days, nine plants were dead and all inoculated plants were dead after 3 weeks. No symptoms developed on control plants. C. gloeosporioides was reisolated from stem pieces of all inoculated plants, and the morphology of the reisolated pathogen was the same as that of the initially isolated pathogen. To our knowledge, this is the first report of anthracnose caused by C. gloeosporioides on S. tragus in Russia. Reference: (1) B. C. Sutton. Page 15 in: Colletotrichum Biology, Pathology and Control. J. A. Bailey and M. J. Jeger, eds. CAB International, Wallingford, UK, 1992.

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First Report of Anthracnose of Salsola tragus Caused by Colletotrichum gloeosporioides in Greece

Plant Disease ◽

10.1094/pd-90-0971b ◽

2006 ◽

Vol 90 (7) ◽

pp. 971-971 ◽

Cited By ~ 4

Author(s):

D. K. Berner ◽

C. A. Cavin ◽

M. B. McMahon ◽

I. Loumbourdis

Keyword(s):

Biological Control ◽

Colletotrichum Gloeosporioides ◽

Type A ◽

The United States ◽

Ionic Surfactant ◽

Potential Candidate ◽

Conidial Suspension ◽

Type B ◽

First Report ◽

Stems And Leaves

In early October of 2005, dying Salsola tragus L. (Russian thistle, tumbleweed), family Chenopodiaceae, plants were found along the Aegean Sea at Kryopigi Beach, Greece (40°02′29″N, 23°29′02″E, elevation 0 m). All of the 30 to 40 plants in the area were diseased and approximately 80% were dead or dying. All plants were relatively large (approximately 1 m tall × 0.5 m diameter), and living portions of diseased plants were flowering. Dying plants had irregular, necrotic lesions extending the length of the stems. Leaves of these plants were also necrotic. Lesions on stems and leaves were dark brown and usually coalesced. Diseased stem pieces were taken to the European Biological Control Laboratory, USDA, ARS at the American Farm School in Thessaloniki, Greece. There, diseased stem pieces were surface disinfested for 15 min with 0.5% NaOCl and placed on moist filter paper in petri dishes. Numerous, waxy subepidermal acervuli with black setae were observed in all lesions after 2 to 3 days. Conidiophores were simple, short, and erect. Conidia were one-celled, hyaline, ovoid to oblong, falcate to straight, 12.9 to 18.0 × 2.8 to 5.5 μm (mode 16.1 × 4.5 μm). These characters conformed to the description of Colletotrichum gloeosporioides (Penz.) Penz. & Sacc. in Penz. (2). Conidia were placed on modified potato carrot agar and axenic cultures from these isolations were sent to the quarantine facility of the Foreign Disease-Weed Science Research Unit, USDA, ARS, Fort Detrick, MD for testing. On the basis of DNA sequences, two variants within S. tragus have been described in California and named “Type A” and “Type B” (1). Conidia were harvested from 14-day-old cultures grown on 20% V8 juice agar, and healthy stems and leaves of 18 30-day-old plants of S. tragus Type A and 10 Type B plants were spray inoculated with an aqueous conidial suspension (1.0 × 106 conidia/ml plus 0.1% non-ionic surfactant). Three control plants of each type were sprayed with water and surfactant only. Plants were placed in an environmental chamber (18 h of dew in darkness at 25°C). After 1 day, all plants were transferred to a greenhouse (20 to 25°C, 30 to 50% relative humidity, and natural light augmented with 12-h light periods with 500-W sodium vapor lights). Lesions developed on stems of inoculated Type A plants after 5 days. After 14 days, all inoculated Type A plants were dead. Lesions on Type B plants were small and localized; all plants were diseased but no plants died. No symptoms occurred on control plants. C. gloeosporioides was reisolated 14 to 21 days after inoculation from stem pieces of all inoculated plants of both types of S. tragus. This isolate of C. gloeosporioides is a destructive pathogen on S. tragus Type A and is a potential candidate for biological control of this weed in the United States. To our knowledge, this is the first report of anthracnose caused by C. gloeosporioides on S. tragus in Greece. A voucher specimen has been deposited with the U.S. National Fungus Collections, Beltsville, MD (BPI 871126). Nucleotide sequences for the internal transcribed spacers (ITS 1 and 2) were deposited in GenBank (Accession No. DQ344621) and exactly matched sequences of the teleomorph, Glomerella cingulata. References: (1) F. Ryan and D. Ayres. Can. J. Bot. 78:59, 2000. (2) B. C. Sutton. Page 15 in: Colletotrichum Biology, Pathology and Control. J. A. Bailey and M. J. Jeger, eds. CAB International Mycological Institute, Wallingford, UK, 1992.

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First Report of Thielaviopsis paradoxa Causing Fruit Rot on Sala (Salacca edulis) in Thailand

Plant Disease ◽

10.1094/pdis.2001.85.2.230c ◽

2001 ◽

Vol 85 (2) ◽

pp. 230-230

Author(s):

K. Soytong ◽

S. Jitkasemsuk

Keyword(s):

Sodium Hypochlorite ◽

Rainy Season ◽

Culture Collection ◽

Potato Dextrose Agar ◽

Fruit Rot ◽

Fungal Culture ◽

Distilled Water ◽

Humidity Chamber ◽

Institute Of Technology ◽

First Time

Sala (Salacca edulis, a hybrid between S. wallichiana and S. glabrescens) is extensively cultivated in Southeast Asia for its highly valued fruit (1). During the rainy season in 1999, a fruit rot of sala caused by Thielaviopsis paradoxa (2) was observed to occur on immature and mature fruits for the first time in Trad and Chantaburi provinces, Thailand. Infected fruit discolored brown to black and appeared rotted with white mycelia on the lesions. Fruit eventually abscised. Conidiophores of the fungus were usually straight and hyaline to pale brown. The conidia (8.75 to 12.5 × 3.75 to 5.5 μm) were cylindrical to elliptical and also hyaline to pale brown. The brown, smooth, and ovate chlamydospores (15 to 25 × 8.7 to 14.5 μm) were borne terminally in chains from short hyphal branches. To fulfill Koch's postulates, six isolates of the fungus were grown on potato-dextrose agar for 7 days. Plugs of mycelia agar (0.5 cm in diameter) from each isolate were inoculated onto fresh fruit (four fruit per isolate) after the surface was disinfected with 10% sodium hypochlorite for 3 min. Non-inoculated fruits with sterile distilled water were served as controls. After incubation at 30°C and 80% RH in a humidity chamber for 4 days, lesions occurred on all the inoculated fruit. The fungus was subsequently recovered from the lesions. One isolate has been deposited in the Fungal Culture Collection, King Mongkut's Institute of Technology, Ladkrabang, Thailand (TF 1-6/1999). References: (1) G. Hamballi et al. 1989. Proceedings of the First PROSEA International Symposia, Indonesia. (2) A. Johnston and C. Booth. 1983. Plant Pathologist's Pocketbook. CMI, Surrey, England.

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First Report of Fusarium proliferatum Causing Rot of Garlic Bulbs (Allium sativum) in India

Plant Disease ◽

10.1094/pdis-08-11-0649 ◽

2012 ◽

Vol 96 (2) ◽

pp. 290-290 ◽

Cited By ~ 9

Author(s):

N. Ravi Sankar ◽

Gundala Prasad Babu

Keyword(s):

Sodium Hypochlorite ◽

Allium Sativum ◽

Morphological Characteristics ◽

Aerial Mycelium ◽

Its Region ◽

Fusarium Proliferatum ◽

Distilled Water ◽

Sequence Comparisons ◽

First Report ◽

Plant Pathol

In September 2009, diseased garlic bulbs (Allium sativum L. cv. Yamuna Safed) were received from producers and exporters in Hyderabad, Andra Pradesh, India. From 2009 to 2010, similar symptoms were observed on stored garlic bulbs (cvs. Yamuna Safed and Agrifound White) in Chittoor, Kadapa, and Hyderabad districts. In some locations, approximately 60% of the garlic bulbs were affected. At first, infected bulbs showed water-soaked, brown spots and then the disease progressed as small, slightly depressed, tan lesions. A total of 120 diseased samples were collected from all localities. Infected tissues were surface sterilized in 1% sodium hypochlorite for 2 min, rinsed three times in sterile distilled water, plated on potato dextrose agar (PDA), and incubated at 25°C for 7 days. Resultant fungal colonies were fast growing with white aerial mycelium and violet to dark pigments. Hyphae were septate and hyaline. Conidiophores were short, simple, or branched. Microconidia were abundant, single celled, oval or club shaped, measuring 4.5 to 10.5 × 1.3 to 2.5 μm, and borne in chains from both mono-and polyphialides. Macroconidia were not produced. On the basis of morphological characteristics, the pathogen was identified as Fusarium proliferatum (Matsushima) Nirenberg (2). Identification was confirmed by amplification of the internal transcribed spacer (ITS) region. Genomic DNA was extracted from pure cultures of an isolate, and the ITS region was amplified using the ITS4/5 primer pair. PCR amplicons of approximately 574 bp were obtained from isolates, and sequence comparisons with GenBank showed 99% similarity with F. proliferatum (Accession No. FN868470.1). Sequence from this study was submitted to GenBank nucleotide database (Accession No. AB646795). Pathogenicity tests were conducted with three isolates of the fungus following the method of Dugan et al. (1). Each assay with an isolate consisted of 10 garlic cloves disinfected in 1% sodium hypochlorite for 45 s, rinsed with sterile distilled water, and injured to a depth of 4 mm with a sterile 1-mm-diameter probe. The wounds were filled with PDA colonized by the appropriate isolate from a 5-day-old culture. Ten cloves for each tested isolate received sterile PDA as a control. The cloves were incubated at 25°C for 5 weeks; tests were repeated once. After 17 days, rot symptoms similar to the original symptoms developed on all inoculated cloves and F. proliferatum was consistently reisolated from symptomatic tissue, fulfilling Koch's postulates. No fungi were recovered from control cloves. F. proliferatum has been reported on garlic in the northwestern United States (1), Serbia (4), and Spain (3). To our knowledge, this is the first report of F. proliferatum causing rot disease on garlic bulbs in India. References: (1) F. M. Dugan et al. Plant Pathol. 52:426, 2003. (2) J. F. Leslie and B. A. Summerell. The Fusarium Laboratory Manual. Blackwell Publishing, Oxford, UK, 2006. (3) D. Palmero et al. Plant Dis. 94:277, 2010. (4) S. Stankovic et al. Eur. J. Plant Pathol. 48:165, 2007.

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First Report of Macrophomina phaseolina on Cotton (Gossypium hirsutum) in Georgia

Plant Disease ◽

10.1094/pdis.1999.83.5.487b ◽

1999 ◽

Vol 83 (5) ◽

pp. 487-487 ◽

Cited By ~ 4

Author(s):

R. E. Baird ◽

J. H. Brock

Keyword(s):

Gossypium Hirsutum ◽

Field Study ◽

Production System ◽

Macrophomina Phaseolina ◽

Potato Dextrose Agar ◽

Distilled Water ◽

Gossypium Hirsutum L ◽

First Report ◽

Cotton Seeds ◽

Secondary Roots

In a field study evaluating the diversity and density of the soilborne mycobiota in a cotton (Gossypium hirsutum L.) production system, Macrophomina phaseolina (Tassi) Goidanich was isolated on potato dextrose agar from dark brown to black lesions on feeder and secondary roots. Multiple proliferations of feeder and secondary roots were also observed. Isolate RB 656 obtained from these lesions was tested for pathogenicity in the greenhouse by mixing 25 ml of 2-week-old cornmeal sand inoculum (3 g of cornmeal, 100 g of sand, and 20 ml of distilled water) with 5 liters of autoclaved soil (Leefield loamy sand, pH 6.2) per pot (40 × 200 cm). Control pots containing autoclaved soil alone were included for comparison. On 17 September, 10 cotton seeds of DPL 90 were sown per pot. Each treatment had five replications. Forty days after planting, plant heights from pots containing M. phaseolina were lower (14.8 cm) than those in the control pots (19.6 cm), but stand counts were similiar. On this date, four plants were left in each pot to allow the remaining seedlings to reach full maturity. On 9 December, the four plants per replicate pot were removed and roots evaluated for damage. Lesions similiar to those seen originally were observed on the secondary and feeder roots of the infested pots, and the characteristic proliferation of feeder and secondary roots was noted. Tap roots in pots containing M. phaseolina were smaller (11.6 cm) than in the control pots (18.6 cm). Isolate RB 656 was reisolated from the damaged roots in the treated pots. This is the first report of M. phaseolina on cotton in Georgia.

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First Report of Colletotrichum siamense Causing Anthracnose on Zinnia elegans Jacq. in China

Plant Disease ◽

10.1094/pdis-04-20-0803-pdn ◽

2020 ◽

Author(s):

Wen Li ◽

Yue-qiu He ◽

Tao Fu ◽

Li Lin ◽

Feng Liu ◽

...

Keyword(s):

Phylogenetic Trees ◽

Colletotrichum Gloeosporioides ◽

Disease Incidence ◽

Morphological Characteristics ◽

Zinnia Elegans ◽

Likelihood Method ◽

Distilled Water ◽

First Report ◽

Colletotrichum Siamense ◽

Leaf Tissues

Zinnia elegans (syn. Zinnia violacea), known as common zinnia, is one of the most spectacular ornamental plants in the family Asteraceae. Zinnia plants are widely cultivated in China for their impressive range in flower colours and profuse bloom over a long period. In April 2019, Zinnia plants grown in Ningbo Botanical Garden (29°56′57″N, 121°36′20″E) were found to have many circular necrotic lesions. In the early infection stage, the lesions appeared as small circular specks which developed later into large spots (15 to 32 mm diameter). Typical symptoms appeared to be grayish white centers with a chlorotic edges and disease incidence reached approximately 80% of plants in the affected field. Moreover, the growth of Zinnia plants was seriously affected by the disease. To identify the causative pathogen associated with the disease, 10 symptomatic leaves were collected from ten different Zinnia plants. Leaf tissues were cut from the lesion margins, surface sterilized with 75% ethanol for 30 seconds and rinsed three times in sterile distilled water. The leaf tissues were then dipped into 10% sodium hypochlorite for 2-3 minutes, washed three times in distilled water and dried on a sterile filter paper. After drying, the surface-sterilized leaf discs were transferred to potato dextrose agar (PDA) plates and incubated at 28°C for 2 to 3 days under the 12 h photoperiod. A total of ten pure fungal isolates were obtained and all the isolates displayed the same colony structure. Afterwards, three pure strains were randomly selected (F1, F3 and F5) for further study. The fungal colonies showed gray to brownish aerial mycelia with pink-colored masses of conidia. Conidia were one-celled, hyaline, cylindrical to subcylindrical, spindle-shaped with obtuse ends, measuring from 15.6 to 17.3 × 4.6 to 5.1 μm with both ends rounded. These morphological characteristics were consistent with the description of Colletotrichum gloeosporioides complex (Weir et al. 2012). The identity of a representative isolate, F3, was confirmed by a multilocus approach. Genomic DAN of isolate F3 was extracted and partial sequences of actin (ACT), chitin synthase (CHS), glyceraldehyde-3-phosphate dehydrogenase (GAPDH), ribosomal internal transcribed spacer (ITS), manganese-superoxide dismutase (SOD2) , glutamine synthatase (GS), beta-tubulin (TUB2) and calmodulin (CAL) were amplified and sequenced as previously described (Weir et al. 2012). These nucleotide sequences were deposited in GenBank (accession MN972436 to MN972440, and MT266559 to MT266561; all sequences in FASTA format are shown (Supplementary S1). BLAST analysis of ITS, ACT, CHS, GAPDH and GS sequences from the F3 isolate revealed similarity to C. gloeosporioides voucher strain ZH01 with 100%, 100%，99%, 99% and 99% identity, respectively. SOD, TUB2 and CAL sequences showed similarity to C. siamense with 100%, 100% and 100% identity, respectively. The phylogenetic trees were constructed by Maximum Likelihood method (ML) using JTT model implemented in the MEGA 7. Results inferred from the concatenated sequences (ACT, CHS, GAPDH, ITS, SOD, GS, TUB2 and CAL) placed the isolate F3 within the C. siamense cluster (Supplementary S2). To confirm pathogenicity of the fungus, Koch’s postulates were conducted by spraying 20 Zinnia plants (60-day-old) with a 1 × 106 conidia/ml suspension. Plants were maintained in the growth chamber at 25°C and 85% relative humidity. After 10 to 15 days, symptoms were observed on all inoculated leaves and resembled those observed in the field, whereas the control plants remained asymptomatic. Here, C. siamense was isolated only from the infected Zinnia leaves and identified by morphological and gene sequencing analyses. C. siamense has been reported in many crops in China (Yang et al. 2019; Chen et al. 2019; Wang et al. 2019). However, to our knowledge, this is the first report of anthracnose caused by C. siamense on Zinnia elegans in China. References Chen, X., Wang, T., Guo, H., Zhu, P. K., and Xu, L. 2019. First report of anthracnose of Camellia sasanqua caused by Colletotrichum siamense in China. Plant Dis. 103:1423-1423. Wang, Y., Qin, H. Y., Liu, Y. X., Fan, S. T., Sun, D., Yang, Y. M., Li, C. Y., and Ai, J. 2019. First report of anthracnose caused by Colletotrichum siamense on Actinidia arguta in China. Plant Dis. 103:372-373. Weir, B. S., Johnston, P. R., and Damm, U. 2012. The Colletotrichum gloeosporioides species complex. Stud. Mycol. 73: 115-180. Yang, S., Wang, H. X., Yi, Y. J., and Tan, L. L. 2019. First report that Colletotrichum siamense causes leaf spots on Camellia japonica in China. Plant Dis. 103:2127-2127.

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First Report of Brown Blight Disease Caused by Colletotrichum gloeosporioides on Camellia sinensis in Anhui Province, China

Plant Disease ◽

10.1094/pdis-08-13-0896-pdn ◽

2014 ◽

Vol 98 (2) ◽

pp. 284-284 ◽

Cited By ~ 16

Author(s):

M. Guo ◽

Y. M. Pan ◽

Y. L. Dai ◽

Z. M. Gao

Keyword(s):

Camellia Sinensis ◽

Colletotrichum Gloeosporioides ◽

Tea Plant ◽

Anhui Province ◽

Molecular Characteristics ◽

Fluorescent Light ◽

Distilled Water ◽

Conidial Suspension ◽

First Report ◽

Twig Blight

Yellow Mountain fuzz tip, a cultivar of Camellia sinensis (L.) Kuntze, is commonly grown in the Yellow Mountain region in Anhui Province of China. During 2011 to 2012, leaf and twig blight on tea plants occurred from July to September in growing regions. Symptoms of blight on leaves of infected plants were detected in 30 to 60% of the fields visited and up to 500 ha were affected each year. Symptoms began as small, water-soaked lesions on young leaves and twigs and later became larger, dark brown, necrotic lesions, 1 to 3 mm in diameter on leaves and 2 to 5 mm long on twigs. To determine the causal agent, symptomatic leaf tissue was collected from plants in Gantang and Tangkou townships in September 2012. Small pieces of diseased tea leaves and twigs were surface-disinfested in 2% NaClO for 3 min, rinsed twice in distilled water, plated on potato dextrose agar, and incubated at 28°C for 5 days. Eleven isolates were recovered and all cultures produced white-to-gray fluffy aerial hyphae and were dark on the reverse of the plate. The hyphae were hyaline, branching, and septate. Setae were 2- to 3-septate, dark brown, acicular, and 78.0 to 115.0 μm. Conidiogenous cells were hyaline, short, branchless, cylindrical, and 11.3 to 21.5 × 4.2 to 5.3 μm. Conidia were hyaline, aseptate, guttulate, cylindrical, and 12.5 to 17.3 × 3.9 to 5.8 μm. Appresoria were ovate to obovate, dark brown, and 8.4 to 15.2 × 7.8 to 12.9 μm. DNA was amplified using the rDNA-ITS primer pair ITS4/ITS5 (3), glyceraldehyde-3-phosphate dehydrogenase gene (GAPDH) primer pair GDF/GDR (2) and beta-tubulin 2 gene (Tub2) primer pair Btub2Fd/Btub4Rd (4). Sequences (GenBank Accession Nos. KC913203, KC913204, and KC913205) of the 11 isolates were identical and revealed 100% similarity to the ITS sequence of strain P042 of Colletotrichum gloeosporioides (EF423527), 100% identity to the GAPDH of isolate C07009 of C. gloeosporioides (GU935860), and 99% similarity to Tub2 of isolate 85 of C. gloeosporioides (AJ409292), respectively. Based on the above data, the 11 isolates were identified as C. gloeosporioides (Penz.) Penz. & Sacc. To confirm pathogenicity, Koch's postulate was performed and 4 ml of conidial suspension (1 × 105 conidia/ml) of each of the 11 isolates was sprayed on five leaves and five twigs per plant on four 12-month-old Yellow Mountain fuzz tip plants. Control plants were sprayed with distilled water. The inoculated plants were maintained at 28°C in a greenhouse with constant relative humidity of 90% and a 12-h photoperiod of fluorescent light. Brown necrotic lesions appeared on leaves and twigs after 7 days, while the control plants remained healthy. The experiments were conducted three times and the fungus was recovered and identified as C. gloeosporioides by both morphology and molecular characteristics. Tea plant blight caused by C. gloeosporioides was identified in Brazil (1), but to our knowledge, this is the first report of C. gloeosporioides causing tea leaf and twig blight on Yellow Mountain fuzz tip plants in Anhui Province of China. References: (1) M. A. S. Mendes et al. Page 555 in: Embrapa-SPI/Embrapa-Cenargen, Brasilia, 1998. (2) M. D. Templeton et al. Gene 122:225, 1992. (3) T. J. White et al. Page 315 in: PCR Protocols: A Guide to Methods and Applications. Academic Press, San Diego, 1990. (4) J. H. C. Woudenberg et al. Persoonia 22:56, 2009.

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