First Report of Lasmenia sp. and Two Species of Gliocephalotrichum on Rambutan in Hawaii

Rambutan (Nephelium lappaceum L.) is a tropical fruit grown in Hawaii for the exotic fruit market. Fruit rot was observed periodically during 1998 and 1999 from two islands, Hawaii and Kauai, and severe fruit rot was observed during 2000 in orchards in Kurtistown and Papaikou on Hawaii. Symptoms were characterized by brown-to-black, water-soaked lesions on the fruit surface that progressed to blackening and drying of the pericarp, which often split and exposed the aril (flesh). In certain cultivars, immature, small green fruits were totally mummified. Rambutan trees with high incidence of fruit rot also showed symptoms of branch dieback and leaf spot. Lasmenia sp. Speg. sensu Sutton, identified by Centraalbureau voor Schimmelcultures (Baarn, the Netherlands), was isolated from infected fruit and necrotic leaves. Also associated with some of the fruit rot and dieback symptoms were Gliocephalotrichum simplex (J.A. Meyer) B. Wiley & E. Simmons, and G. bulbilium J.J. Ellis & Hesseltine. G. simplex was isolated from infected fruit, and G. bulbilium was isolated from discolored vascular tissues and infected fruit. Identification of species of Gliocephalotrichum was based on characteristics of conidiophores, sterile hairs, and chlamydospores (1,4). Culture characteristics were distinctive on potato dextrose agar (PDA), where the mycelium of G. bulbilium was light orange (peach) without reverse color, while G. simplex was golden-brown to grayish-yellow with dark brown reverse color. Both species produced a fruity odor after 6 days on PDA. In pathogenicity tests, healthy, washed rambutan fruits were wounded, inoculated with 30 μl of sterile distilled water (SDW) or a fungus spore suspension (105 to 106 spores per ml), and incubated in humidity chambers at room temperature (22°C) under continuous fluorescent light. Lasmenia sp. (strain KN-F99-1), G. simplex (strain KN-F2000-1), and G. bulbilium (strains KN-F2001-1 and KN-F2001-2) produced fruit rot symptoms on inoculated fruit and were reisolated from fruit with typical symptoms, fulfilling Koch's postulates. Controls (inoculated with SDW) had lower incidence or developed less severe symptoms than the fungus treatments. Inoculation tests were conducted at least twice. To our knowledge, this is the first report of Lasmenia sp. in Hawaii and the first report of the genus Gliocephalotrichum on rambutan in Hawaii. These pathogens are potentially economically important to rambutan in Hawaii. G. bulbilium has been reported previously on decaying wood of guava (Psidium guajava L.) in Hawaii (2), and the fungus causes field and postharvest rots of rambutan fruit in Thailand (3). References: (1) J. J. Ellis and C. W. Hesseltine. Bull. Torrey Bot. Club 89:21, 1962. (2) D. F. Farr et al. Fungi on Plants and Plant Products in the United States. The American Phytopathological Society, St. Paul, MN, 1989. (3) N. Visarathanonth and L. L. Ilag. Pages 51–57 in: Rambutan: Fruit Development, Postharvest Physiology and Marketing in ASEAN. ASEAN Food Handling Bureau, Kuala Lumpur, Malaysia, 1987. (4) B. J. Wiley and E. G. Simmons. Mycologia 63:575, 1971.

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First Report of Gliocephalotrichum bulbilium Causing Fruit Rot of Posthavest Mangosteen in China

Plant Disease ◽

10.1094/pdis-09-13-0917-pdn ◽

2014 ◽

Vol 98 (7) ◽

pp. 994-994 ◽

Cited By ~ 1

Author(s):

Y. X. Li ◽

W. X. Chen ◽

A. Y. Liu ◽

Q. L. Chen ◽

S. J. Feng

Keyword(s):

Its Region ◽

The United States ◽

Psidium Guajava ◽

Morphological Characters ◽

Fruit Rot ◽

Diseased Plant ◽

Garcinia Mangostana ◽

Single Spore ◽

Tropical Fruit ◽

First Report

Mangosteen (Garcinia mangostana L., Guttiferae) is a tropical fruit renowned for its pleasant taste, rich nutrition, and medicinal value. Little research about mangosteen diseases during storage and transport has been reported. In June of 2012, fruit rots on mangosteens imported from Thailand were observed in Guangzhou, China. In infected fruits, pericarps showed an increased firmness, were discolored to deep pink, and the edible aril became brown and rotten. In order to search for the etiological agent of this rot symptom, infected mangosteens were analyzed. Diseased mangosteen tissues were surface-sterilized with 70% alcohol, then with 0.1% HgCl2, dipped in sterilized water three times, and placed onto potato dextrose agar (PDA) at 26°C. The fungi isolated from tissues of the pericarp and aril were similar in morphology and grew rapidly, covering the plate surface (9 mm diameter) after 2 to 3 days of incubation at 26°C. The morphological characters of 10 single-spore isolates were observed. These isolates showed light yellow to light brown fertile colonies on PDA. On corn meal agar (CMA), conidiophores were erect, arising from wide hyphae; they were composed of a basal stipe ending in a penicillate conidiogenous apparatus with directly subtending sterile stipe extensions ranging from 74.5 to 195.0 μm long. Conidia were unicellular, smooth, oblong to elliptical, 6.3 to 8.5 × 2.5 to 3.0 μm, and accumulated in a mucilaginous mass. Chlamydospores were multicellular, dark brown, regular in shape and thick-walled, and 40.0 to 52.5 μm in diameter. On the basis of these morphological characters, these isolates were identified as Gliocephalotrichum bulbilium (2). To confirm the identity of this fungus, genomic DNA of two isolates was extracted, and fragments of ITS region and β-tubulin gene were amplified by PCR, sequenced, and compared with sequences of Gliocephalotrichum species available in NCBI GenBank. Both DNA regions (GenBank Accession Nos. KF716166 and KF716168) had sequence similarities of 99% and 97%, respectively, to other G. bulbilium sequences at GenBank. Pathogenicity tests were conducted on three detached fruits for two isolates. Fruits were inoculated using 5-mm mycelial disks with conidia taken from 3-day-old cultures of G. bulbilium isolate Gb1 and Gb10 grown on PDA. Controls were inoculated with PDA disks only. All treated fruits were kept individually in a humid chamber at 26°C. Tests were repeated twice. Three days after inoculation, white mycelial growth for Gb was observed at inoculation sites. Eight days after inoculation, mycelium of Gb nearly covered the fruit, causing fruit rot, and the pericarp became hard and light in color. The control fruit did not rot. G. bulbilium was re-isolated from diseased plant tissue, thus fulfilling Koch's postulates. G. bulbilium has been reported causing postharvest fruit rot of rambutan (Nephelium lappaceum) and guava (Psidium guajava) in some locations (3,4). Moreover, the fungus caused cranberry fruit rot in the United States (1). To our knowledge, this is the first report of G. bulbilium causing postharvest fruit rot of mangosteen in China. It is uncertain whether the fungus infected mangosteen in Thailand and was carried to China due to commercial relationship. References: (1) C. Constantelos et al. Plant Dis. 95:618, 2011. (2) C. Decock et al. Mycologia 98:488, 2006. (3) L. M. Serrato-Diaz et al. Plant Dis. 96:1225, 2012. (4) A. Sivapalan et al. Australas. Plant Pathol. 27:274, 1998.

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First Report of Fruit Rot of Loquat Caused by an Alternaria sp. in Taiwan

Plant Disease ◽

10.1094/pdis-94-4-0481b ◽

2010 ◽

Vol 94 (4) ◽

pp. 481-481 ◽

Cited By ~ 6

Author(s):

Y. Ko ◽

C. W. Liu ◽

S. S. Chen ◽

C. Y. Chen ◽

K. S. Yao ◽

...

Keyword(s):

Black Spot ◽

The United States ◽

Spore Suspension ◽

Fruit Rot ◽

Eriobotrya Japonica ◽

Fluorescent Light ◽

American Phytopathological Society ◽

Tropical Fruit ◽

First Report ◽

Alternaria Sp

During March 2007, a fruit rot disease was observed in several loquat (Eriobotrya japonica (Thunberg) Lindley) fields located in Taichung, Nantou, and Miaoli counties. Loquat is a valuable fruit crop grown predominantly in central Taiwan, and hence, even a minor yield loss by this new disease is economically significant. Symptoms on fruits initially appeared as small lesions (<1 mm) that later developed into light-to-dark brown, circular, larger (7 mm), sunken lesions, indicating invasion of a pathogen into the fruit. Pieces of rotted fruit tissue (1 × 1 × 1 mm) were immersed for 1 min in 3% commercial bleach, followed by 70% ethanol, cultured on potato dextrose agar (PDA), and incubated under constant fluorescent light (185 ± 35 μE·m–2·s–1) at 24°C for 2 days. Three single conidial isolates (AS1 to AS3) were selected and used in morphological and pathogenicity studies. All three isolates were identified as an Alternaria sp. (1–3) and formed abundant, dark brown mycelium when cultured on PDA with light at 24°C. Conidiophores were 60 to 89 × 3 to 5 μm, densely fasciculate, cylindrical, simple or branched, and had distinct conidial scars. Conidia were 12 to 74 × 6 to 14 μm, golden brown, straight or curved, obclavate with beaks measuring half the length of the conidium, and observed in chains of 10 or more spores with four to seven transverse septa and several longitudinal septa. Pathogenicity tests were conducted twice by inoculating eight surface-sterilized wounded or unwounded fruits with each of the three isolates in each experiment. Two cuts (1 × 1 × 1 mm) were made on each fruit 3 cm apart with a sterile scalpel, and a 300-μl spore suspension (2 × 105 conidia per ml) was placed on each wound. Similarly, a 300-μl spore suspension was placed on unwounded fruits and air dried for 5 min. Control fruits were similarly treated with sterile water. Inoculated fruits were enclosed in a plastic bag and kept at 24 ± 1°C. Symptoms of soft rot were observed on 60% (unwounded) and 100% (wounded) of inoculated fruits 5 days after inoculation, while control fruits did not develop disease symptoms. Reisolation from the symptomatic fruits consistently yielded an Alternaria sp. This fungus previously has been reported as the causal agent of fruit rot or black spot of papaya, mango, kiwifruit, pear, and carambola from Australia, India, Malaysia, South Africa, and the United States (1–3). To our knowledge, this is the first report of fruit rot of loquat caused by an Alternaria sp. in Taiwan. To manage this disease, growers may resort to fungicidal sprays followed by bagging of fruits to reduce pre- and postharvest losses. References: (1) A. L. Jones and H. S. Aldwinckle. Compendium of Apple and Pear Diseases. The American Phytopathological Society. St. Paul, MN, 1990. (2) R. C. Ploetz. Diseases of Tropical Fruit Crops. CABI Publishing. Wallingford, Oxfordshire, UK, 2003. (3) R. C. Ploetz et al. Compendium of Tropical Fruit Diseases. The American Phytopathological Society. St. Paul, MN, 1994.

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First Report of Lasiodiplodia theobromae Causing Inflorescence Blight and Fruit Rot of Longan (Dimocarpus longan L.) in Puerto Rico

Plant Disease ◽

10.1094/pdis-05-13-0473-pdn ◽

2014 ◽

Vol 98 (2) ◽

pp. 279-279 ◽

Cited By ~ 4

Author(s):

L. M. Serrato-Diaz ◽

L. I. Rivera-Vargas ◽

R. Goenaga ◽

R. D. French-Monar

Keyword(s):

Puerto Rico ◽

Fruit Rot ◽

Fluorescent Light ◽

Its2 Region ◽

Tropical Fruit ◽

Lasiodiplodia Theobromae ◽

First Report ◽

Wide Range ◽

Dimocarpus Longan ◽

Β Tubulin

Dimocarpus longan L., commonly known as longan, is a tropical fruit tree of the Sapindaceae family. From 2008 to 2010, a disease survey for longan was conducted in March and October in Puerto Rico. Fruit rot and inflorescence blight (rotting of the rachis, rachilla, and flowers) were observed in fields of longan at the USDA-ARS Research Farm in Isabela, and two commercial orchards in Puerto Rico. Tissue sections (1 mm2) of diseased inflorescences and surface of the fruit were disinfested with 70% ethanol, rinsed with sterile water, and transferred to acidified potato dextrose agar (APDA). Three isolates of Lasiodiplodia theobromae (Pat.) Griffon & Maubl. (Lt) were isolated from symptomatic tissue and identified morpho-molecularly using a taxonomic key for the Botryosphaeriaceae and DNA sequence analysis (1). In APDA, colonies of Lt had initial greenish-gray aerial mycelia that turned dark brown with age. Pycnidia were dark brown to black. Immature conidia were sub-ovoid to ellipsoid, apex rounded, truncate at the base, thick-walled, hyaline, and one-celled, becoming dark brown, two-celled, and with irregular longitudinal striations when mature. Conidia (n = 50) for all the isolates averaged 26.9 μm long by 13 μm wide. For molecular identification, the ITS1-5.8S-ITS2 region and fragments of the β-tubulin and elongation factor 1-alpha (EF1-α) genes were sequenced and BLASTn searches done in GenBank. Accession numbers of gene sequences of Lt submitted to GenBank were KC964546, KC964547, and KC964548 for ITS region; KC964549, KC964550, and KC964551 for β-tubulin; and KC964552, KC964553, and KC964554 for EF1-α. For all genes used, sequences were 99 to 100% identical to reference isolate CBS164.96 of Lt reported in GenBank (accessions AY640255, EU673110, and AY640258). Pathogenicity tests were conducted on six random healthy non-detached inflorescences of longan and six healthy detached fruits per isolate. Unwounded inflorescences and fruit were inoculated with 5-mm mycelial disks from 8-day-old pure cultures grown in APDA. Inflorescences were enclosed in plastic bags for 5 days under field conditions while fruits were kept in a humid chamber using plastic boxes for 5 days under laboratory conditions of 25°C and 12 h of fluorescent light. Untreated controls were inoculated with APDA disks only. The experiment was repeated once. Five days after inoculation, isolates of Lt caused inflorescence blight, fruit rot, and aril (flesh) rot. Inflorescences turned brown and flower mummification was observed on the inflorescences. The exocarp (peel) and endocarp (aril) turned dark brown and mycelial growth and pycnidia of Lt were observed on fruits. Untreated controls did not show any symptoms and no fungi were re-isolated from tissue. In diseased inflorescences and fruits, Lt was re-isolated from diseased tissue and identified using morphological and molecular parameters, thus fulfilling Koch's postulates. Lt has been reported to cause dieback, stem end rot, and fruit rot on a wide range of plants host (2,4). In longan, Lt has been reported causing fruit rot in Thailand (3). To our knowledge, this is the first time that Lt has been reported causing inflorescence blight in longan and the first report of Lt causing fruit rot in Puerto Rico. References: (1) A. J. L. Phillips. Key to the various lineages in “Botryosphaeria” Version 01 2007. Retrieved from http://www.crem.fct.unl.pt/botryosphaeria_site/key.htm , 26 November 2013. (2) B. Slippers et al. Mycologia 97:99, 2005. (3) P. Suwanakood et al. Asian J. Biol. Ed. 3:47, 2007. (4) A. F. Wright and P. F. Harmon. Plant Dis. 93:962, 2009.

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First Report of Calonectria hongkongensis Causing Fruit Rot of Rambutan (Nephelium lappaceum)

Plant Disease ◽

10.1094/pdis-01-13-0008-pdn ◽

2013 ◽

Vol 97 (8) ◽

pp. 1117-1117 ◽

Cited By ~ 2

Author(s):

L. M. Serrato-Diaz ◽

E. I. Latoni-Brailowsky ◽

L. I. Rivera-Vargas ◽

R. Goenaga ◽

P. W. Crous ◽

...

Keyword(s):

Mycelial Growth ◽

Elongation Factor ◽

Type Specimen ◽

Fruit Rot ◽

Fluorescent Light ◽

Mycelium Growth ◽

Tropical Fruit ◽

First Report ◽

Nephelium Lappaceum ◽

Pure Cultures

Fruit rot of rambutan is a pre- and post-harvest disease problem of rambutan orchards. In 2011, fruit rot was observed at USDA-ARS orchards in Mayaguez, Puerto Rico. Infected fruit were collected and 1 mm2 tissue sections were surface disinfested with 70% ethanol followed by 0.5% sodium hypochlorite. Infected fruit were rinsed with sterile, deionized, double-distilled water and transferred to acidified potato dextrose agar (APDA). Plates were incubated at 25 ± 1°C for 6 days. Three isolates of Calonectria hongkongensis (Cah), CBS134083, CBS134084, and CBS134085, were identified morphologically using taxonomic keys (2,3). In APDA, colonies of Cah produced raw sienna to rust-colored aerial mycelial growth. Conidiophores of Cah had a penicillate arrangement of primary to quaternary branches of 2 to 6 phialides. Conidia (n = 50) were cylindrical, hyaline, 1-septate, rounded at both ends, and 44 to 52 μm × 3.5 to 4.5 μm. Conidiophores produced terminal and lateral stipe extensions with terminal sphaeropedunculate vesicles that were 8 to 12 μm wide. Subglobose to ovoid perithecia, 300 to 500 μm × 200 to 350 μm and orange to red-brown, were produced in groups of 3. Asci were clavate and contained 8 ascospores aggregated at the top of the ascus. Ascospores (n = 50) were hyaline, guttulate, fusoid with rounded ends, straight to curved, 1-septate with constriction at the septum, and 28 to 36 μm × 4 to 7 μm. For molecular identification, the ITS rDNA, fragments of β-tubulin (BT), histone H3 (HIS3), and elongation factor (EF1-α) genes were amplified by PCR, sequenced, and compared using BLASTn with Calonectria spp. submitted to the NCBI GenBank. The sequences of Cah submitted to GenBank include accessions KC342208, KC342206, and KC342207 for ITS; KC342217, KC342215, and KC342216 for BT; KC342211, KC342209, and KC342210 for HIS3; and KC342214, KC342212, and KC342213 for EF1α. The sequences were >99% or identical with the ex-type specimen of Cah CBS 114828 for all genes used. Pathogenicity tests were conducted on 5 healthy superficially sterilized fruits per isolate. Both scalpel-wounded and unwounded fruit tissues were inoculated with 5-mm mycelial disks from 8-day-old pure cultures grown in APDA. Untreated controls were inoculated with APDA disks only. Fruits were kept in a humid chamber for 8 days at 25°C under 12 h of fluorescent light. The test was repeated once. Three days after inoculation (DAI), white mycelial growth was observed on the fruit. Five DAI, the fruit changed color from red to brown and yellowish mycelia colonized 50 to 62% of the fruit surface. Eight DAI, all the fruit turned brown, the mycelium growth covered the entire fruit, and conidiophores were produced on spinterns (hairlike appendages). Fruit rot of spinterns, exocarp (skin), endocarp (aril), and light brown discoloration were observed inside the fruit. Untreated controls showed no symptoms of fruit rot and no fungi were reisolated from tissue. Cah was reisolated from diseased tissue, fulfilling Koch's postulates. Calonectria spp. (or their Cylindrocladium asexual states) have been associated with lychee decline syndrome in North Vietnam (1). Both fruits belong to the Sapindaceae family. To our knowledge, this is the first report of Cah causing fruit rot of rambutan. References: (1) L. M. Coates et al. Diseases of Longan, Lychee and Rambutan. Pages 307-325 in: Diseases of Tropical Fruit Crops. R. C. Ploetz, ed. CABI Publishing, Cambridge, MA, 2003. (2) P. W. Crous. Taxonomy and Pathology of Cylindrocladium (Calonectria) and Allied Genera. APS Press, St Paul, MN, 2002. (3) P. W. Crous, et al. Stud. Mycol. 50:415, 2004.

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First Report of Botryosphaeria obtusa as Causal Agent of Olive Tree Branch Dieback in Tunisia

Plant Disease ◽

10.1094/pdis-01-12-0026-pdn ◽

2012 ◽

Vol 96 (6) ◽

pp. 905-905 ◽

Cited By ~ 4

Author(s):

M. Chattaoui ◽

A. Rhouma ◽

M. Msallem ◽

M. Pérez ◽

J. Moral ◽

...

Keyword(s):

Sodium Hypochlorite ◽

Olive Tree ◽

Fruit Rot ◽

Fluorescent Light ◽

Internal Transcribed Spacer Region ◽

Canker Disease ◽

First Report ◽

Botryosphaeria Obtusa ◽

Olive Trees ◽

Branch Dieback

A branch dieback of olive trees (Olea europaea L. cv. Manzanilla de Sevilla) was observed in 2010 in an orchard (50 ha), located in the Testour region of northern Tunisia. More than 50% of trees were severely damaged by the disease. Symptomatic trees presented dead branches and wilted leaves, which remained attached to the shoots, and the affected tissues appeared abnormally dark compared with the inner bark of healthy branches. Numerous pycnidia were observed on the surface of the infected branches. For diagnosis, symptomatic stems were collected and small pieces of discolored tissues were excised from lesion margins, surface sterilized in 0.5% sodium hypochlorite for 1 min, rinsed and dried on sterilized filter paper, then placed on acidified Difco potato dextrose agar plates (APDA; 2.5 ml of 25% lactic acid per liter). Plates were incubated at 25°C for 4 to 5 days, and hyphal tips from developing fungal colonies were transferred to PDA and placed under fluorescent light (12 h/day). A fastgrowing, pycnidia-producing fungus was consistently isolated, with conidia exuding onto the agar surface of 10-day-old cultures. On the basis of colony characteristics, isolates were identified as Botryosphaeria obtusa (3). Conidia were large, dark brown, aseptate, rounded at both ends or truncate at base, and 25 to 26.8 × 10.5 to 12.03 μm. Pathogenicity tests were performed on detached stems of cv. Manzanilla by 7-mm diameter mycelial plugs cut from actively growing cultures of the fungus. Stems (30 cm length) were cleaned, surface sterilized with sodium hypochlorite (0.25% for 2 min), and wounded with a sterilized scalpel. Mycelial disks were placed over wounds and wrapped with Parafilm to prevent desiccation. Control stems were mock inoculated with sterile agar plugs. Inoculated and control stems were placed in polyethylene boxes and incubated at 25°C. After 45 days, inoculated stems developed brown discoloration, and small dark pycnidia appeared on stem surfaces. Controls remained healthy. Koch's postulates were verified by isolating the fungus from symptomatic stems. To confirm the identification, DNA of one isolate was extracted and the fungal primers ITS1 and ITS4 (4) were used to amplify the internal transcribed spacer region of rDNA. Purified amplicons were sequenced and a BLAST search of the GenBank database revealed 99% homology with B. obtusa isolate HO166525.1. The anamorph of the fungus, Diplodia seriata, has been recognized as the cause of fruit rot of olive (1) and branch canker or dieback (2). To our knowledge, this is the first report of a canker disease of olive trees caused by B. obtusa in Tunisia. References: (1) J. Moral et al. Plant Dis. 92:311, 2008. (2) J. Moral et al. Phytopathology 100:1340, 2010. (3) A. Taylor et al. Australas. Plant Pathol. 34:187, 2005. (4) T. J. White et al. Page 315 in: PCR Protocols: A Guide to Methods and Applications. Academic Press, San Diego, CA, 1990.

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First Report of Gliocephalotrichum bulbilium Causing Cranberry Fruit Rot in New Jersey and Massachusetts

Plant Disease ◽

10.1094/pdis-12-10-0926 ◽

2011 ◽

Vol 95 (5) ◽

pp. 618-618 ◽

Cited By ~ 1

Author(s):

C. Constantelos ◽

V. P. Doyle ◽

A. Litt ◽

P. V. Oudemans

Keyword(s):

New Jersey ◽

The United States ◽

Psidium Guajava ◽

Fungal Species ◽

Fruit Rot ◽

Colletotrichum Acutatum ◽

Water Control ◽

First Report ◽

Brunei Darussalam ◽

Nephelium Lappaceum

Cranberry (Vaccinium macrocarpon) fruit were collected as part of a fruit rot survey conducted in September 2010 on farms in New Jersey and Massachusetts. There are more than 20 fungal species reported as causing fruit rot (2) and symptoms are generally not diagnostic. The rotted fruit were surface sterilized in a 10% bleach solution for 5 min, sliced in half, and plated on V8 agar (nonclarified). A novel, fast-growing fungus that produced sporulating orange-brown colonies emerged from 5% of the fruit collected on three of the farms included in the survey. The fungus was notable as the only species present in the rotted fruit, suggesting it may be pathogenic. The conidia were produced as gloeoid masses on phialidic conidiogenous cells arranged in a polyverticillate penicillus. The conidiogenous cells were subtended at variable distances by zero to four sterile appendages that formed on the lightly pigmented conidiophore. On the basis of these characteristics, the fungus was identified as a species of Gliocephalotrichum (3). Further investigation of the growth medium revealed the presence of clustered, red-brown chlamydospores that were produced abundantly in all isolates. These structures, also known as bulbils, are restricted to two species in the genus, G. bulbilium and G. longibrachium (1). On average, the bulbils were 42.0 × 48.3 μm and conidia were 5.75 × 2.5 μm. On the basis of size and shape of conidia and presence of bulbils, the isolates were identified as G. bulbilium (1). To confirm the identity of the fungus, genomic DNA was extracted and ITS1-5.8S-ITS2 and the 5′ end of the β-tubulin gene were amplified and sequenced (1). The sequences (GenBank Accession Nos. HQ828060 and HQ828061) were compared with published sequences of Gliocephalotrichum isolates (1) and results confirmed the cranberry isolates were G. bulbilium. The isolates were tested for pathogenicity on harvested cranberry fruit. Fifty ripe cranberry fruit (cv. Stevens) were inoculated by injecting approximately 20 μl (using a 26G 9.5-mm needle) of conidia (1 × 105 ml–1) into the side of each berry. As a comparison, isolates of two common cranberry fruit rot pathogens, Colletotrichum acutatum and C. gloeosporioides, were inoculated on to fruit using the same technique. A water-only inoculation was used as the control. Fruit rot developed on all inoculated fruit except the water control. In the case of G. bulbilium, all fruit rotted within 2 days, whereas the other two species developed symptoms within 4 to 7 days. G. bulbilium and both species of Colletotrichum were consistently reisolated from all of the respectively inoculated fruit. To our knowledge, this is the first report of G. bulbilium causing fruit rot on cranberry. The species has been reported as an important postharvest fruit rot (4) on rambutan (Nephelium lappaceum) in Thailand, rambutan and guava (Psidium guajava) in Hawaii, and durian (Durio spp.) in Brunei Darussalam. This report of G. bulbilium extends the range within the United States to include Louisiana, Hawaii, Wisconsin, West Virginia, New Jersey, and Massachusetts (2). References: (1) C. Decock et al. Mycologia 98:488, 2006. (2) D. F. Farr and A. Y. Rossman. Fungal Databases. Systematic Mycology and Microbiology Laboratory, ARS, USDA. Retrieved from http://nt.ars-grin.gov/fungaldatabases/ , 16 December 2010. (3) A. Rossman et al. Mycologia, 85:685, 1993. (4) A. Sivapalan et al. Australas. Plant Pathol. 27:274, 1998.

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First Report of Fruit Rot and Associated Branch Dieback of Almond in California Caused by a Phomopsis Species Tentatively Identified as P. amygdali

Plant Disease ◽

10.1094/pdis.1999.83.11.1073c ◽

1999 ◽

Vol 83 (11) ◽

pp. 1073-1073 ◽

Cited By ~ 7

Author(s):

J. E. Adaskaveg ◽

H. Förster ◽

J. H. Connell

Keyword(s):

Disease Incidence ◽

Morphological Characteristics ◽

The United States ◽

Tree Canopy ◽

Fruit Rot ◽

Control Treatment ◽

Field Inoculation ◽

First Report ◽

Branch Dieback ◽

Summer Fruit

A fruit rot of almond (Prunus dulcis (Mill.) D. Webb.) was observed in an orchard in Durham, CA (Butte County), in June of 1998 after an unusually wet spring with a total precipitation of 17.2 cm for April and May. Disease incidence on fully developed fruit of almond cv. Sonora was nearly 90% in the lower tree canopy by July. Almond cv. Nonpareil grown in alternate rows in the same orchard was much less affected. Fruit symptoms included extensive grayish brown discolored and shriveled hulls, often associated with a clear gum secretion and shriveled kernels. Affected fruit frequently abscised. Leaf symptoms and branch dieback were not associated with the disease in 1998. In May of 1999, however, extensive twig dieback was observed on almond cv. Sonora in the same orchard. Isolations from more than 100 symptomatic fruit were conducted from 9 sampling sites in the 9-ha orchard. Based on morphological characteristics, the same fungus was isolated from 93% of the fruit. The fungus also was isolated consistently from samples exhibiting twig dieback. During a major disease survey conducted in 1998, the fungus was only incidentally isolated from almond fruit from other California orchards. Ascomata were not observed in vivo or in vitro. The fungus produced alpha and beta spores in pycnidia when cultured on potato dextrose agar. Spore measurements were obtained from 10 spores for each of 3 isolates obtained from fruit or twig dieback of almond cv. Sonora. Conidial dimensions of fruit and twig isolates were very similar. Based on spore sizes, with alpha spores measuring 5.3 to 7.5 (to 8) × 1.7 to 2.5 μm and beta spores measuring12.8 to 29.8 × 0.6 to 0.7 μm, the fungus was tentatively identified as Phomopsis amygdali (Del.) Tuset & Portilla (2). Previous reports on this fungus (2), however, indicated that beta spores are not produced in culture, and disease symptoms have not been observed on fruit. The fungus was morphologically different from other species of Phomopsis reported from almond and other Prunus species, including P. mali Roberts, P. padina (Sacc. & Roum.) Died., P. parabolica Petrak, P. perniciosa Grove, P. pruni (Ellis & Dearn.) Wehm., P. prunorum (Cooke) Grove, P. ribetejana Camara, and P. stipata (Lib.) Sutton (3). Field inoculation studies were performed in May of 1999 on almond cvs. Carmel and Mission. Almond fruit were wounded (2 × 2 × 2 mm) or left unwounded and were sprayed with water (control) or a suspension of alpha spores (105 spores per ml). Branches were bagged for 4 days to maintain high humidity. Fruit symptoms on cv. Carmel were observed after 4 weeks on wounded and nonwounded inoculated fruit, and P. amygdali was successfully reisolated from diseased tissue. No symptoms were observed in the control treatment for almond cv. Carmel or in any treatment for cv. Mission. This is the first report of P. amygdali causing a late spring and summer fruit rot and associated branch dieback of almond in North America (1). References: (1) D. F. Farr et al. 1989. Fungi on Plants and Plant Products in the United States. The American Phytopathological Society, St. Paul, MN. (2) J. J. Tuset and M. T. Portilla. Taxonomic status of Fusicoccum amygdali and Phomopsis amygdalina. Can. J. Bot. 67:1275, 1989. (3) F. A. Uecker. 1988. A World List of Phomopsis Names with Notes on Nomenclature, Morphology, and Biology. Mycologia Memoir No. 13. J. Cramer, Berlin.

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First Report of Stem-End Rot of Mango Caused by Phomopsis mangiferae in Taiwan

Plant Disease ◽

10.1094/pdis-93-7-0764a ◽

2009 ◽

Vol 93 (7) ◽

pp. 764-764 ◽

Cited By ~ 2

Author(s):

Y. Ko ◽

C. W. Liu ◽

C. Y. Chen ◽

S. Maruthasalam ◽

C. H. Lin

Keyword(s):

Mangifera Indica ◽

Morphological Characteristics ◽

Pathogenic Fungi ◽

The United States ◽

Fluorescent Light ◽

Continuous Exposure ◽

Tropical Fruit ◽

First Report ◽

Agar Plug ◽

Rot Disease

Mango (Mangifera indica L.) is grown on approximately 20,000 ha in Taiwan. It is an economically important crop and the income of many fruit farmers comes primarily from mango production. During 2006 and 2007, a stem-end rot disease was observed 1 week after harvest on 28 to 36% of stored mangoes picked from six orchards in the Pingtung, Tainan, and Kaoshiung regions. Two popular mango cultivars, Keitt and Irwin, showed greater susceptibility to this disease, while ‘Haden’ was found to be moderately susceptible. In storage, symptoms initially appeared as light-to-dark brown lesions surrounding peduncles. Rot symptoms advanced slowly but eventually penetrated the mesocarp, which consequently reduced the commercial value of fruits. The fungus formed abundant pycnidia (0.1 to 0.6 mm in diameter) on infected fruits in advanced stages of symptom development. Pieces of symptomatic fruits plated on acidified potato dextrose agar (PDA) and incubated at 25 ± 1°C consistently yielded the same fungus. A single conidial isolate was cultured. Pycnidia developed on PDA after continuous exposure to light for 9 to 14 days. On the basis of morphological characteristics, the fungus was identified as Phomopsis mangiferae L. (2,3). Pycnidia released two types of conidia: α-conidia (5 to 10 × 2.3 to 4.0 μm) were hyaline and oval to fusoid; and β-conidia (15.0 to 37.5 × 1.3 to 2.5 μm) were hyaline and filiform with characteristic curves. Conidiophores were hyaline, filiform, simple or branched, septate, and 15 to 75 μm long. Cultures incubated under continuous fluorescent light (185 ± 35 μE·m–2·s–1) at 25°C for 3 days were used as inoculum for pathogenicity tests. Five fruits from ‘Keitt’ were wounded with a sterilized scalpel and each wound (2 × 2 × 2 mm) was inoculated with either a 5-mm mycelium agar plug or a 0.5-ml spore suspension (105 conidia per ml) of the fungus. Five wounded fruits inoculated with 5-mm PDA plugs or sterile water alone served as controls. Inoculated areas were covered with moist, sterile cotton. Fruits were enclosed in plastic bags and incubated at 24°C for 3 days. The test was performed three times. The same symptoms were observed on all inoculated fruits, whereas no decay was observed on control fruits. Reisolations from the inoculated fruits consistently yielded P. mangiferae, thus fulfilling Koch's postulates. This disease has previously been reported in Australia, Brazil, China, Cuba, India, Malaysia, and the United States (1). To our knowledge, this is the first report of P. mangiferae causing stem-end rot disease on mangoes in Taiwan. Our report necessitates taking preventive strategies in the field, prior to or after harvest, to contain postharvest losses in mangoes. References: (1) G. I. Johnson. Page 39 in: Compendium of Tropical Fruit Diseases. R. C. Ploetz et al., eds. The American Phytopathological Society. St. Paul, MN, 1994. (2) R. C. Ploetz, ed. Page 354 in: Diseases of Tropical Fruit Crops. CABI Publishing. Wallingford, UK, 2003. (3) E. Punithalingam. No. 1168 in: Descriptions of Pathogenic Fungi and Bacteria. CMI, Kew, Surrey, UK, 1993.

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First Report of Lasiodiplodia theobromae Causing Postharvest Fruit Rot on Guava (Psidium guajava) in Malaysia

Plant Disease ◽

10.1094/pdis-12-20-2732-pdn ◽

2021 ◽

Author(s):

Kar Yan Zee ◽

Norhayu Asib ◽

Siti Izera Ismail

Keyword(s):

Morphological Characteristics ◽

Its Region ◽

Psidium Guajava ◽

Fruit Rot ◽

Pathogenicity Test ◽

Tropical Fruit ◽

Lasiodiplodia Theobromae ◽

First Report ◽

Guava Fruit ◽

Initial Symptoms

Guava (Psidium guajava L.) is an economically important tropical fruit crop and is cultivated extensively in Malaysia. In September and October 2019, postharvest fruit rot symptoms were observed on 30% to 40% of guava fruit cv. Kampuchea in fruit markets of Puchong and Ipoh cities in the states of Selangor and Perak, Malaysia. Initial symptoms appeared as brown, irregular, water-soaked lesions on the upper portion of the fruit where it was attached to the peduncle. Subsequently, lesions then progressed to cover the whole fruit (Fig.1A). Lesions were covered with an abundance of black pycnidia and grayish mycelium. Ten symptomatic guava fruit were randomly collected from two local markets for our investigation. For fungal isolation, small fragments (5×5 mm) were excised from the lesion margin, surface sterilized with 0.5% NaOCl for 2 min, rinsed three times with sterile distilled water, placed on potato dextrose agar (PDA) and incubated at 25 °C with 12-h photoperiod for 2-3 days. Eight single-spore isolates with similar morphological characteristics were obtained and two representative isolates (P8 and S9) were characterized in depth. Colonies on PDA were initially composed of grayish-white aerial mycelium, but turned dark-gray after 7 days (Fig. 1B). Abundant black pycnidia were observed after incubation for 4 weeks. Immature conidia were hyaline, aseptate, ellipsoid, thick-walled, and mature conidia becoming dark brown and 1-septate with longitudinal striations, 25.0 − 27.0 ± 2.5 × 13.0 − 14.0 ± 1.0 μm (n = 30) (Fig.1C, D). On the basis of morphology, both representative isolates were identified as Lasiodiplodia theobromae (Pat.) Griffon & Maubl. (Alves et al. 2008). For molecular identification, genomic DNA of the two isolates was extracted using the DNeasy plant mini kit (Qiagen, USA). The internal transcribed spacer (ITS) region of rDNA and translation elongation factor 1-alpha (EF1-α) genes were amplified using ITS5/ITS4 and EF1-728F/EF1-986R primer set, respectively (White et al. 1990, Carbone and Kohn 1999). BLASTn analysis of the resulting ITS and EF1-α sequences indicated 100% identity to L. theobromae ex-type strain CBS 164.96 (GenBank accession nos: AY640255 and AY640258, respectively) (Phillips et al. 2013). The ITS (MW380428, MW380429) and EF1-α (MW387153, MW387154) sequences were deposited in GenBank. Phylogenetic analysis using the maximum likelihood based on the combined ITS-TEF sequences indicated that the isolates formed a strongly supported clade (100% bootstrap value) to the related L. theobromae (Kumar et al. 2016) (Fig.2). A pathogenicity test of two isolates was conducted on six healthy detached guava fruits per isolate. The fruit were surface sterilized using 70% ethanol and rinsed twice with sterile water prior inoculation. The fruit were wound-inoculated using a sterile needle according to the method of de Oliveira et al. (2014) and five-mm-diameter mycelial agar plugs from 7-days-old PDA culture of the isolates were placed onto the wounds. Six additional fruit were wound inoculated using sterile 5-mm-diameter PDA agar plugs to serve as controls. Inoculated fruit were placed in sterilized plastic container and incubated in a growth chamber at 25 ± 1 °C, 90% relative humidity with a photoperiod of 12-h. The experiment was conducted twice. Five days after inoculation, symptoms as described above developed on the inoculated sites and caused a fruit rot, while control treatment remained asymptomatic. L. theobromae was reisolated from all symptomatic tissues and confirmed by morphological characteristics and confirmed by PCR using ITS region. L. theobromae has recently been reported to cause fruit rot on rockmelon in Thailand (Suwannarach et al. 2020). To our knowledge, this is the first report of L. theobromae causing postharvest fruit rot on guava in Malaysia. The occurrence of this disease needs to be monitored as this disease can reduce the marketable yield of guava. Preventive strategies need to be developed in the field to reduce postharvest losses.

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First Report of Penicillium glabrum Causing a Postharvest Fruit Rot of Pomegranate (Punica granatum) in the Piedmont Region of Italy

Plant Disease ◽

10.1094/pdis-94-8-1066b ◽

2010 ◽

Vol 94 (8) ◽

pp. 1066-1066 ◽

Cited By ~ 7

Author(s):

D. Spadaro ◽

M. T. Amatulli ◽

A. Garibaldi ◽

M. L. Gullino

Keyword(s):

Punica Granatum ◽

The United States ◽

Fruit Rot ◽

Morphological Identification ◽

Sterile Water ◽

Sequence Coverage ◽

Cotton Lint ◽

Centraalbureau Voor ◽

First Report ◽

Piedmont Region

Pomegranates (Punica granatum L.) are widely grown in many tropical and subtropical countries, especially in the moderate climate of the Mediterranean Region. In Italy, pomegranates are harvested from September to November. During October and November 2009 in Orbassano (Piedmont Region), postharvest fruit rots were observed on pomegranates (cv. Dente di Cavallo) after 30 days of storage at 5°C. Infected fruits showed soft, brown tissues that later were covered with masses of green mycelium, conidiophores, and hyphae of a fungus. Tissues were excised from the margin between the healthy and diseased tissues on pomegranates and plated on potato dextrose agar amended with 25 μg of streptomycin per liter. The fungus recovered from the tissue produced abundant mycelium and conidia on PDA after 7 days at 20 ± 2°C. Colonies consisting of dense erect conidiophores appeared velvety, gray-green, and the reverse of PDA culture was usually yellow to yellow-orange. Conidiophores were monoverticilliate, consisting of an unbranched stipe, smooth to finely roughened, and germinating in a whorl of 10 to 12 phialides. Phialides were flask shaped and 8 to 12 × 3 to 3.5 μm. Conidia were produced in typical long columns, globose to subglobose, smooth to finely roughened, with walls somewhat echinulate, and ranging from 3 to 3.5 μm in diameter (3). Preliminary morphological identification of the fungus was confirmed by PCR using genomic DNA extracted from the mycelia of pure cultures. One sequence, obtained through the amplification of ribosomal region ITS1-5.8S-ITS2 (4), was blasted in GenBank and showed 100% sequence coverage and 99% similarity to ribosomal sequences of Penicillium glabrum. The sequence was deposited in GenBank (Accession No. GU734815). Pathogenicity was tested on 10 ripe fruits (cv. Dente di Cavallo) surface sterilized with 1% sodium hypochlorite. To make inoculum, 7-day-old PDA cultures of the fungus were flooded with sterile water and scraped with a sterile spatula. Resulting suspensions were filtered through two layers of sterile cotton lint and brought to a final concentration of 105 conidia/ml with sterile distilled water. Conidial suspensions (30 μl) were placed on artificial wounds generated on the fruit surface. Control fruits were treated with sterile water. Ten days after inoculation, P. glabrum was reisolated on PDA from the inoculated fruit. Control fruits were symptomless. Previously, P. glabrum was reported on pomegranate in Greece (1). Other species of Penicillium, including P. expansum, P. implicatum, and P. purpurogenum, also were reported on pomegranate in the United States (2), Slovakia, and India, respectively. To our knowledge, this is the first report of P. glabrum causing a postharvest fruit rot of pomegranate in Italy. References: (1) G. A. Bardas et al. Plant Dis. 93:1347, 2009. (2) A. M. French. California Plant Disease Host Index. Calif. Dep. Food Agric., Sacramento, 1989. (3) R. A. Samson et al. Introduction to Food-Borne Fungi. Centraalbureau voor Schimmelcultures, Baarn, the Netherlands, 1995. (4) T. J. White et al. Page 315: in: PCR Protocols: A Guide to Methods and Applications. Academic Press, San Diego, 1990.

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