First Report of Dragon Fruit Stem Canker Caused by Lasiodiplodia theobromae in Bangladesh

Cassia fistula, a member of the Fabaceae, known as the golden shower tree, is native to South Asia. It is now distributed worldwide and is popular as an ornamental plant as well as being used in herbal medicine. In October 2013, symptoms of stem canker were observed on C. fistula in a nursery (108°38′ E, 22°87′ N) in Nanning, Guangxi, China. The symptoms began as small brown lesions, which enlarged over several months to long, striped, slightly sunken lesions, 1 to 9 cm in width and 16 to 135 cm in length. The conspicuous cankers had vertical cracks outlining the canker and evenly spaced horizontal cracks, eventually resulting in whole plants dying back. The cankers were found on 90% of six-year-old plants in this nursery and were also observed in other plantings. On potato dextrose agar (PDA), isolates with similar morphological characteristics were consistently recovered from symptomatic plant tissues after surface sterilization in 75% ethanol for 30 sec and then in 0.1% mercuric chloride for 2 min. Over 100 conidia were examined from three isolates and were found to be elliptical and hyaline when immature, becoming dark brown, one-septate, and longitudinally striate when mature and ranging from 20 to 31 × 11 to 16 μm (average 25.5 × 13.6 μm). The rDNA internal transcribed spacer (ITS) region of isolate LC-1 was sequenced (GenBank Accession No. KM387285), and it showed 100% identity to Lasiodiplodia theobromae (Pat.) Griffon & Maubl. (GenBank KC964548), confirming the morphological identification (2) as L. theobromae (also known as Botryosphaeria rhodina (Cooke) Arx). A culture of this isolate has been preserved in the Guangxi Academy of Agricultural Sciences fungal collection. The pathogenicity of the isolate was tested on healthy twigs and branches of C. fistula trees in a field setting at Guangxi Agricultural Vocational-Technical College, Nanning, Guangxi, in June and August 2014. For each treatment, five green twigs and five 2-year-old branches were used. Five adjacent needle punctures were made on each branch with a sterilized needle. A mycelial plug was then placed on the wound of each branch and wrapped with Parafilm. Control twigs were treated with sterile PDA plugs. One week later, typical lesions were observed on the inoculated branches, with symptoms becoming more extensive after two weeks, but no symptoms were seen on the controls. Koch's postulates were fulfilled by re-isolation of L. theobromae from diseased branches. L. theobromae is recognized as an important wood pathogen and has been reported to cause cankers, dieback, and fruit and root rots in over 500 different hosts, including perennial fruit and nut trees, vegetable crops, and ornamental plants (2). The fungus has been reported on C. fistula in India since the 1970s (1); however, to our knowledge, this is the first report of L. theobromae infecting C. fistula in China. References: (1) R. S. Mathur. The Coelomycetes of India. Bishen Singh Mahendra Pal Singh, Delhi, India, 1979. (2) J. R. Úrbez-Torres et al. Plant Dis. 92:519, 2008.

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First report of stem canker of dragon fruit caused by Alternaria spp. in Taiwan

New Disease Reports ◽

10.5197/j.2044-0588.2020.041.035 ◽

2020 ◽

Vol 41 ◽

pp. 35

Author(s):

X.L. Jin ◽

Y.Z. Ko ◽

M.S. Siti Nordahliawate ◽

M.H. Mohd ◽

Y.C. Chiang

Keyword(s):

Stem Canker ◽

First Report ◽

Dragon Fruit

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First Report of Lasiodiplodia theobromae Associated with Stem Canker of Almond in California

Plant Disease ◽

10.1094/pdis-11-12-1033-pdn ◽

2013 ◽

Vol 97 (7) ◽

pp. 994-994 ◽

Cited By ~ 9

Author(s):

S. F. Chen ◽

D. Morgan ◽

R. H. Beede ◽

T. J. Michailides

Keyword(s):

Average Length ◽

Stem Canker ◽

Macrophomina Phaseolina ◽

Disease Diagnosis ◽

Type Specimens ◽

Lasiodiplodia Theobromae ◽

First Report ◽

Agar Plug ◽

Almond Trees ◽

Negative Controls

California is a major almond (Prunus dulcis) producer in the world. In September 2012, 2-year-old almond trees from an orchard in Fresno Co. with stem cankers were submitted for disease diagnosis. In a survey of the orchard, 12 ha (1,500 Nonpareil and 1,800 Monterey almond trees) of 48 ha trees had been killed apparently due to a stem canker. The cankers developed above the graft union, were covered with amber sap, and often girdled the trunk. Isolations made from tissues at the canker margins onto acidified potato dextrose agar (PDA) yielded two fungi, Macrophomina phaseolina (Tassi) Goid and Lasiodiplodia theobromae (Pat.) Griffon & Maubl (1). M. phaseolina and L. theobromae were isolated from eight and two of 10 cankered trees, respectively. No mixed infections were found. M. phaseolina isolates were characterized by gray hyphae that turned black with developing microsclerotia. L. theobromae isolates were characterized by white, aerial mycelium that turned mouse gray after 5 days. Young conidia were ellipsoidal, thick walled, initially hyaline, granular, and nonseptate; aged conidia were brown, 1-septate with longitudinal striations in the wall. Identity was confirmed by analyses of the internal transcribed spacer (ITS), β-tubulin 2 (BT2), and the translation elongation factor 1-alpha (TEF-1α) gene regions. BLAST searches at GenBank showed a high identity with reference sequences of type specimens both for M. phaseolina (isolates 7E64 to 7E69: ITS, 100%; BT2, 99%; TEF-1α, 99%) and L. theobromae (isolates 7E86 to 7E88: ITS, 99%; BT2, 99%; TEF-1α, 100%). Sequences of three gene regions were deposited as GenBank accessions KC357271 to KC357279 (ITS); KC357280 to KC357288 (BT2); and KC357289 to KC357297 (TEF-1α). The pathogenicity of M. phaseolina and L. theobromae to P. dulcis cultivars Butte, Carmel, Nonpareil, and Padre was investigated in an orchard at KARE using four isolates of M. phaseolina (7E64, 7E65, 7E66, and 7E69) and two isolates of L. theobromae (7E86 and 7E88). Ten 2-year-old branches per isolate from 7-year-old trees were inoculated with each isolate in late September 2012, after removing the bark with a 7-mm cork borer and placing a 7-day-old 7-mm-diameter agar plug bearing mycelium of each isolate directly into the fresh wound, mycelium side down. Ten additional branches of each of the four cultivars were inoculated with sterile PDA plugs and served as negative controls. Three weeks after inoculation, the average lesion produced by M. phaseolina on Butte, Carmel, Nonpareil, and Padre was 53, 52, 41, and 37 mm in length, respectively. Lesions produced by L. theobromae were 191, 206, 194, and 103 mm in length on the four cultivars, respectively. No disease lesion, only wounds, were produced on negative controls. Lesions produced by both pathogens were longer (P < 0.05) than wounds on the controls (average length 10 mm on all cultivars). Both L. theobromae isolates killed branches of cultivars Butte, Carmel, and Nonpareil in 2 weeks. M. phaseolina and L. theobromae were reisolated from the inoculated branches, and no fungus was reisolated from controls. Based on pathogenicity results, L. theobromae is more virulent to almond branches than M. phaseolina. To our knowledge, this is the second report of M. phaseolina (2) and the first report of L. theobromae as pathogens of P. dulcis trees in California. References: (1) A. Alves et al. Fungal Diversity 28:1, 2008. (2) P. Inderbitzin et al. Mycologia 102:1350, 2010.

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First Report of Lasiodiplodia theobromae Causing Stem Canker of Jatropha curcas in Malaysia

Plant Disease ◽

10.1094/pdis-06-11-0482-pdn ◽

2012 ◽

Vol 96 (5) ◽

pp. 767-767 ◽

Cited By ~ 7

Author(s):

R. Sulaiman ◽

S. S. Thanarajoo ◽

J. Kadir ◽

G. Vadamalai

Keyword(s):

Jatropha Curcas ◽

Disease Incidence ◽

Stem Canker ◽

Molecular Characteristics ◽

Width Ratio ◽

Commonwealth Mycological Institute ◽

Lasiodiplodia Theobromae ◽

First Report ◽

Wide Range ◽

Vascular Discoloration

Physic nut (Jatropha curcas L.) is an important biofuel crop worldwide. Although it has been reported to be resistant to pests and diseases (1), stem cankers have been observed on this plant at several locations in Peninsular Malaysia since early February 2008. Necrotic lesions on branches appear as scars with vascular discoloration in the tissue below the lesion. The affected area is brownish and sunken in appearance. Disease incidence of these symptomatic nonwoody plants can reach up to 80% in a plantation. Forty-eight samples of symptomatic branches collected from six locations (University Farm, Setiu, Gemenceh, Pulau Carey, Port Dickson, and Kuala Selangor) were surface sterilized in 10% bleach, rinsed twice with sterile distilled water, air dried on filter paper, and plated on water agar. After 4 days, fungal colonies on the agar were transferred to potato dextrose agar (PDA) and incubated at 25°C. Twenty-seven single-spore fungal cultures obtained from all locations produced white, aerial mycelium that became dull gray after a week in culture. Pycnidia from 30-day-old pure cultures produced dark brown, oval conidia that were two celled, thin walled, and oval shape with longitudinal striations. The average size of the conidia was 23.63 × 12.72 μm with a length/width ratio of 1.86. On the basis of conidial morphology, these cultures were identified as Lasiodiplodia theobromae. To confirm the identity of the isolates, the internal transcribed spacer (ITS) region was amplified with ITS1/ITS4 primers and sequenced. The sequences were deposited in GenBank (Accession Nos. HM466951, HM466953, HM466957, GU228527, HM466959, and GU219983). Sequences from the 27 isolates were 99 to 100% identical to two L. theobromae accessions in GenBank (Nos. HM008598 and HM999905). Hence, both morphological and molecular characteristics confirmed the isolates as L. theobromae. Pathogenicity tests were performed in the glasshouse with 2-month-old J. curcas seedlings. Each plant was wound inoculated by removing the bark on a branch to a depth of 2 mm with a 10-mm cork borer. Inoculation was conducted by inserting a 10-mm-diameter PDA plug of mycelium into the wound and wrapping the inoculation site with wetted, cotton wool and Parafilm. Control plants were treated with plugs of sterile PDA. Each isolate had four replicates and two controls. After 6 days of incubation, all inoculated plants produced sunken, necrotic lesions with vascular discoloration. Leaves were wilted and yellow above the point of inoculation on branches. The control plants remained symptomless. The pathogen was successfully reisolated from lesions on inoculated branches. L. theobromae has been reported to cause cankers and dieback in a wide range of hosts and is common in tropical and subtropical regions of the world (2,3). To our knowledge, this is the first report of stem canker associated with L. theobromae on J. curcas in Malaysia. References: (1) S. Chitra and S. K. Dhyani. Curr. Sci. 91:162, 2006. (2) S. Mohali et al. For. Pathol. 35:385, 2005. (3) E. Punithalingam. Page 519 in: CMI Descriptions of Pathogenic Fungi and Bacteria. Commonwealth Mycological Institute, Kew, Surrey, UK. 1976.

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First Report of Lasiodiplodia theobromae Causing Stem Canker on Common Fig (Ficus carica) in Zhejiang Province of China

Plant Disease ◽

10.1094/pdis-05-18-0887-pdn ◽

2018 ◽

Vol 102 (12) ◽

pp. 2656 ◽

Cited By ~ 1

Author(s):

Y. Chen ◽

H. Wei ◽

G. Du ◽

L. Zhu ◽

Q. Song ◽

...

Keyword(s):

Stem Canker ◽

Zhejiang Province ◽

Ficus Carica ◽

Lasiodiplodia Theobromae ◽

First Report ◽

Common Fig

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First Report of Neoscytalidium dimidiatum Causing Stem Canker on Dragon fruit (Hylocereus spp.) in Puerto Rico

Plant Disease ◽

10.1094/pdis-10-20-2265-pdn ◽

2021 ◽

Author(s):

Luz M. Serrato-Diaz ◽

Ricardo Goenaga

Keyword(s):

Puerto Rico ◽

Plant Disease ◽

Stem Canker ◽

The United States ◽

South Florida ◽

First Report ◽

Neoscytalidium Dimidiatum ◽

Dragon Fruit ◽

Fruit Plants ◽

Stem Cankers

Dragon fruit or pitahaya (Hylocereus spp.) is a tropical fruit belonging to the Cactaceae. It is native to Central and South America and commercially grown in the United States in southern California, south Florida and Puerto Rico. During a disease survey from April to June 2020, stem canker was observed in greenhouses and commercial orchards located in Mayaguez and San Sebastian, Puerto Rico with an incidence of 80%. Diseased cladodes (stems) of 1 mm2 tissue sections of 23 pitahaya varieties (NOI-13, NOI-14, NOI-16, N97-15, N97-17, N97-18, N97-20, N97-22, American Beauty, Cosmic Charlie, Halley’s comet, Purple Haze, Alice, Bloody Mary, Dark Star, David Bowie, Delight, Makisupa, Red Jaina, Soul Kitchen, Vietnamese Jaina, Neitzel and Lisa) were disinfested with 70% ethanol, rinsed with double distilled water and plated on potato dextrose agar (PDA) amended with 60 mg/L streptomycin. Three isolates (17B-173-T3, 12C-118-T1 and 13B-131-T2) of Neoscytalidium dimidiatum (syn. N. hyalinum) were identified using taxonomic keys (Crous et al., 2006) and sequencing of the internal transcribed spacer (ITS) with primers ITS5 and ITS4 (White et al. 1990) and translation elongation factor 1 alpha (TEF1-α) with primers EF1-728F and EF1-986R (Carbone and Kohn, 1999). Sequences were compared using the BLASTn tool with N. dimidiatum deposited in NCBI GenBank. In PDA, colonies of N. dimidiatum were initially powdery white and turned grayish-black with age. Arthroconidia (n=50) were dark brown, disarticulating, truncate or cylindrical at the base, thick-walled with 0 to 1 septum, averaging 9.1 X 5.5um in length. GenBank accession numbers of N. dimidiatum DNA sequences were MT921260, MT921261 and MT921262 for ITS and MT920898, MT920899 and MT920900 for TEF1-α. Sequences were 99-100% identical with Ex-isotype CBS145.78 accession numbers KF531816 for ITS and KF531795 for TEF1-α. Pathogenicity tests were conducted on 12 healthy dragon fruit plants of 1.5 years old using three non-detached cladodes per plant. Cladodes were inoculated with 5mm mycelial plugs from 8-day-old pure cultures grown on PDA. Three healthy dragon fruit plants were used as controls and were inoculated with PDA plugs only. The experiment was repeated once. Twenty days after inoculations (DAI), isolates of N. dimidiatum caused stem canker on dragon fruit plants. For all isolates, sunken orange spots averaged 3 X 2 mm in length at 8 DAI. Necrotic blotches with chlorotic halos averaged 10 X 15 mm at 14 DAI; stem cankers with water-soaked tissue were observed at 20 DAI, and arthroconidia and black pycnidia on dry stem cankers at 30 DAI. Untreated controls had no symptoms of stem canker, and no fungi were isolated from tissue. Neoscytalidium dimidiatum has been reported to cause stem canker on Hylocereus spp. in China, Florida, Israel, Malaysia and Taiwan (Chuang et al. 2012; Lan et al., 2012; Ezra et al., 2013; Sanahuja et al., 2016). To our knowledge, this is the first report of N. dimidiatum causing stem canker on dragon fruit in Puerto Rico. References: 1. Carbone, I., and Kohn, L. 1999. Mycologia, 91:553. doi:10.2307/3761358 2. Chuang, M. F. et al. 2012. Plant Disease 96: 906. https://doi.org/10.1094/PDIS-08-11-0689-PDN. 3. Crous, P. W., et al. 2006. Stud. Mycol. 55:235. https://doi.org/10.3114/sim.55.1.235 4. Ezra et al. 2013. Plant Disease 97: 1513. https://doi.org/10.1094/PDIS-05-13-0535-PDN 5. Lan, G.B. et al. 2012. Plant Disease 96: 1702. https://doi.org/10.1094/PDIS-07-12-0632-PDN 6. Sanahuja et al. 2016. Plant Disease 100: 1499. https://doi.org/10.1094/PDIS-11-15-1319-PDN 7. White, T., Bruns, T., Lee, S., and Taylor, J. 1990. Amplification and direct sequencing of fungal ribosomal RNA genes for phylogenetics. Pages 315-322 in: PCR Protocols: A Guide to Methods and Applications. Academic Press, San Diego, CA.

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First Report of Lasiodiplodia theobromae Causing a Stem Canker on Sweetpotato in China

Plant Disease ◽

10.1094/pdis-03-16-0290-pdn ◽

2016 ◽

Vol 100 (9) ◽

pp. 1948-1948 ◽

Cited By ~ 1

Author(s):

L. F. Huang ◽

B. P. Fang ◽

K. M. Li ◽

S. J. Ye ◽

J. Y. Chen ◽

...

Keyword(s):

Stem Canker ◽

Lasiodiplodia Theobromae ◽

First Report

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First Report of Stem Canker of Salsola tragus Caused by Diaporthe eres in Russia

Plant Disease ◽

10.1094/pdis-93-1-0110b ◽

2009 ◽

Vol 93 (1) ◽

pp. 110-110 ◽

Cited By ~ 1

Author(s):

T. Kolomiets ◽

Z. Mukhina ◽

T. Matveeva ◽

D. Bogomaz ◽

D. K. Berner ◽

...

Keyword(s):

United States ◽

Biological Control ◽

Biological Control Agent ◽

Aqueous Suspension ◽

Stem Canker ◽

The United States ◽

Invasive Weed ◽

Voucher Specimen ◽

First Report ◽

Stem Lesions

Salsola tragus L. (Russian thistle) is a problematic invasive weed in the western United States and a target of biological control efforts. In September of 2007, dying S. tragus plants were found along the Azov Sea at Chushka, Russia. Dying plants had irregular, necrotic, canker-like lesions near the base of the stems and most stems showed girdling and cracking. Stem lesions were dark brown and contained brown pycnidia within and extending along lesion-free sections of the stems and basal portions of leaves. Diseased stems were cut into 3- to 5-mm pieces and disinfested in 70% ethyl alcohol. After drying, stem pieces were placed into petri dishes on the surface of potato glucose agar. Numerous, dark, immersed erumpent pycnidia with a single ostiole were observed in all lesions after 2 to 3 days. Axenic cultures were sent to the Foreign Disease-Weed Science Research Unit, USDA, ARS, Ft. Detrick, MD for testing in quarantine. Conidiophores were simple, cylindrical, and 5 to 25 × 2 μm (mean 12 × 2 μm). Alpha conidia were biguttulate, one-celled, hyaline, nonseptate, ovoid, and 6.3 to 11.5 × 1.3 to 2.9 μm (mean 8.8 × 2.0 μm). Beta conidia were one-celled, filiform, hamate, hyaline, and 11.1 to 24.9 × 0.3 to 2.5 μm (mean 17.7 × 1.2 μm). The isolate was morphologically identified as a species of Phomopsis, the conidial state of Diaporthe (1). The teleomorph was not observed. A comparison with available sequences in GenBank using BLAST found 528 of 529 identities with the internal transcribed spacer (ITS) sequence of an authentic and vouchered Diaporthe eres Nitschke (GenBank DQ491514; BPI 748435; CBS 109767). Morphology is consistent with that of Phomopsis oblonga (Desm.) Traverso, the anamorph of D. eres (2). Healthy stems and leaves of 10 30-day-old plants of S. tragus were spray inoculated with an aqueous suspension of conidia (1.0 × 106 alpha conidia/ml plus 0.1% v/v polysorbate 20) harvested from 14-day-old cultures grown on 20% V8 juice agar. Another 10 control plants were sprayed with water and surfactant without conidia. Plants were placed in an environmental chamber at 100% humidity (rh) for 16 h with no lighting at 25°C. After approximately 24 h, plants were transferred to a greenhouse at 20 to 25°C, 30 to 50% rh, and natural light. Stem lesions developed on three inoculated plants after 14 days and another three plants after 21 days. After 70 days, all inoculated plants were diseased, four were dead, and three had more than 75% diseased tissue. No symptoms occurred on control plants. The Phomopsis state was recovered from all diseased plants. This isolate of D. eres is a potential biological control agent of S. tragus in the United States. A voucher specimen has been deposited with the U.S. National Fungus Collections (BPI 878717). Nucleotide sequences for the ribosomal ITS regions (ITS 1 and 2) were deposited in GenBank (Accession No. EU805539). To our knowledge, this is the first report of stem canker on S. tragus caused by D. eres. References: (1) B. C. Sutton. Page 569 in: The Coelomycetes. CMI, Kew, Surrey, UK, 1980. (2) L. E. Wehmeyer. The Genus Diaporthe Nitschke and its Segregates. University of Michigan Press, Ann Arbor, 1933.

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