scholarly journals First Report of Leaf Spot of Tea Oil Camellia (Camellia oleifera) Caused by Lasiodiplodia theobromae in China

Plant Disease ◽  
2014 ◽  
Vol 98 (10) ◽  
pp. 1427-1427 ◽  
Author(s):  
H. Zhu ◽  
X.-Q. Niu ◽  
W.-W. Song ◽  
F.-Y. Yu ◽  
Q.-H. Tang ◽  
...  
Keyword(s):  
Leaf Spot ◽  
Southern China ◽  
Molecular Characteristics ◽  
Its2 Region ◽  
Commonwealth Mycological Institute ◽  
Camellia Oleifera ◽  
Lasiodiplodia Theobromae ◽  
First Report ◽  
Wide Range ◽  
Β Tubulin

Tea oil camellia (Camellia oleifera Abel.), one of the most famous woody oil plants, is distributed and cultivated widely in central and southern China for its strong adaptability. In September 2013, tea oil camellia plants with severe leaf spots were observed in commercial production fields located in Wenchang, Hainan Province. Spots were initially chlorotic, became necrotic and black with a chlorotic halo, developing to cover the entire width of the leaves, and leading to leaf death. Isolations were performed by excising pieces of symptomatic leaves from the lesion margin, surface sterilized with 90% ethanol and 0.6% sodium hypochlorite, and then placed them on potato dextrose agar (PDA). Plates were incubated in a sterile chamber at 26 ± 2°C for 2 days. A fungus was consistently isolated on PDA from all 23 diseased leaf samples. Pure cultures were obtained by monosporic culture technique. After 2 to 3 days of incubation at 26 ± 2°C with a 12-h photoperiod, the fungus initially produced white colonies with dense aerial mycelia, which later turned black (6 to 7 days). The mycelium was fast spreading, branched, and septate. Pycnidia were black, globose, ostiolate, and produced in stroma on the medium surface after 28 days at the same culture conditions as above. Conidia were initially unicellular, subovoid, hyaline, thick-walled with granular content, and 19.8 to 28.9 × 11.5 to 15.7 μm (avg. 25.1 × 13.5 μm). Mature conidia were one-septate and dark brown with longitudinal striations. These observed morphological features suggested that the fungus possessed the same characteristics as previously described for Lasiodiplodia theobromae (Pat.) Griffon & Maubl (syn = Botryodiplodia theobromae) (2). 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 submitted to GenBank were KF811055 for ITS region; KJ639047 for β-tubulin; and KJ639048 for EF1-α. For all genes used, sequences were 99 to 100% identical to reference isolate CBS164.96 of L. theobromae reported in GenBank (NR_111174, EU673110, and AY640258). Hence, both morphological and molecular characteristics confirmed the fungus as L. theobromae. To confirm fungal pathogenicity, ten 1-year-old healthy plants of C. oleifera were inoculated with the fungus. Mycelial plugs (5 mm) taken from a 7-day-old colony growing on PDA were deposited on wounds with a sterilized knife on leaves and covered with moist cotton. Ten additional control plants were treated similarly but with sterile PDA plugs. Plants were maintained in a moist chamber at 26 ± 2°C for 3 days and then in a greenhouse at 25°C and 40% relative humidity. All the inoculated plants produced typical leaf spot symptoms 3 weeks after inoculation. The fungus was consistently re-isolated from all inoculated plants. Control plants did not show any symptoms. 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 (1,2), but not previously reported causing disease on C. oleifera. To our knowledge, this is the first report worldwide of leaf spot of C. oleifera caused by L. theobromae. References: (1) S. Mohali et al. For. Pathol. 35:385, 2005. (2) E. Punithalingam. Page 519 in: CMI Descriptions of Pathogenic Fungi and Bacteria. Commonwealth Mycological Institute, Kew, Surrey, UK, 1976.

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

Plant Disease ◽  
2014 ◽  
Vol 98 (2) ◽  
pp. 279-279 ◽  
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.

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

Plant Disease ◽  
2012 ◽  
Vol 96 (5) ◽  
pp. 767-767 ◽  
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.

scholarly journals First Report of Pestalotiopsis microspora Causing Leaf Spot on Moyeam in China

Plant Disease ◽  
2021 ◽  
Author(s):  
Si-Qi Yuan ◽  
icai Wang ◽  
Ling Lei ◽  
Ju-Yun Hong ◽  
Tuyong Yi ◽  
...  
Keyword(s):  
Nucleotide Sequence ◽  
Leaf Spot ◽  
Disease Incidence ◽  
Universal Primers ◽  
Molecular Characteristics ◽  
Conidial Suspension ◽  
Tubulin Gene ◽  
First Report ◽  
Wide Range ◽  
Β Tubulin

Ampelopsis grossedentata, commonly known as moyeam, has been widely used as health care herbal tea since it contains natural plant protein cream, 17 amino acids, 14 micronutrients and lots of functional flavonoid and provides a wide range of pharmaceutical functions such as antioxidant, anti-inflammatory, antitumor (Carneiro et al. 2021; Zhang et al. 2020). Moyeam is primarily produced in Zhangjiajie, stretching over the area from between 109’40 to 110’20E to between 28’52 to 29’48N, at 1300 to1890 meter above the sea level, with subtropical humid monsoon climate. Its economic value surpasses $1.25 billion in China (Liang et al. 2020). In July 2020, leaf spots were observed on some moyeam plants in Zhangjiajie. Initial spots were pinhead-sized with a yellow halo margin. The spots developed into light brown necrotic spots 6 to 8 mm in diameter, often with a dark brown margin. After 4 days of development, the spots enlarged and coalesced into irregular shape, frequently falling out and giving the leaves a tattered appearance. The infected plants eventually died with disease incidence ranging from 18 to 23%. This disease resulted in production losses of up to $1.7 million in 2020. One fungal isolate was isolated from the symptomatic leaves based on our previously published methods (Yi et al. 2019). Colonies on potato dextrose agar (PDA) were thick and villous with white at the front of the plate and yellowish at the back. After 1 week, the fungus produced conidia, which were spindle-shaped, straight or slightly curved, with 5 cells, 4-euseptates and 2-3 apical accessory filaments. Morphologically, the fungus was similar to Pestalotiopsis spp. Aerial hyphae with vigorous growth were collected for molecular identification. ITS nucleotide sequence of the rDNA and β-tubulin gene were amplified and sequenced with universal primers ITS1/ITS4 and self-designed primers based on β-tubulin gene conserved motif. BLAST searches against GenBank indicated that the ITS nucleotide sequence shared 99% similarity with that of P. microspora (MG808374.1) and the β-tubulin gene sequence shared 99% similarity with that of P. microspora (AF115396.1). Based on morphological and molecular characteristics, the fungus was identified as P. microspora. ITS and the β-tubulin nucleotide sequences were deposited in GenBank (accession no. MW350011 and MW816914). Pathogenicity tests were carried out with the following procedure. Three healthy moyeam seedlings were sprayed with a conidial suspension of 1 x106 conidia/ml while the other three seedlings were sprayed with distilled water as the controls. Plants were maintained in a greenhouse at 28±1°C. After one day of inoculation, symptoms identical to those in the field developed in the plants inoculated with the fungus. In contrast, no symptoms developed on the control plants. P. microspora has been reported to cause diseases in many crops in China. However, this is the first report of P. microspora causing leaf spot in moyeam in China. Identifying the pathogen causing the disease is important to the development of effective disease management strategies for control of this disease.

scholarly journals First Report of Eutypella spp. Associated with Branch Canker of Citrus in California

Plant Disease ◽  
2011 ◽  
Vol 95 (9) ◽  
pp. 1187-1187 ◽  
Author(s):  
A. O. Adesemoye ◽  
A. Eskalen
Keyword(s):  
San Diego ◽  
Its Sequences ◽  
Control Treatment ◽  
Molecular Characteristics ◽  
Its2 Region ◽  
Petroleum Jelly ◽  
Tubulin Gene ◽  
First Report ◽  
Β Tubulin ◽  
Branch Canker

Eutypella is one of the few genera in the Diatrypaceae considered plant pathogens (1). In California, E. vitis and other members of the Diatrypaceae cause branch and trunk canker on grapevine (3,4). Eutypella spp. have not previously been documented as pathogens of citrus. In a 2010 survey on citrus branch canker and dieback in six citrus-growing counties of California, four isolates of Eutypella species were detected in Riverside and San Diego counties. Canker symptoms included dieback and bark cracking, and cuts made through symptomatic trees showed that the cankers were expanding through the center of the tree. Branch samples were collected from 10 trees per orchard and 5 to 10 orchards per county (102 trees for two counties). Pieces of symptomatic tissue (1 to 2 mm2) were plated onto potato dextrose agar amended with 0.01% tetracycline (PDA-tet) and incubated at 25°C for 4 days. All isolates were identified by morphological and molecular characteristics. PCR of isolates was performed in a thermal cycler using two primer pairs, ITS4/5 and Bt2a/2b for amplifying the internal transcribed spacer (ITS1), 5.8S, and ITS2 region and the β-tubulin gene, respectively (2,3). PCR products were sequenced at the University of California, Riverside Genomics Core and the sequences compared in a BLAST search. Four isolates identified as Eutypella spp. included two (UCR1088 and UCR1101) from San Diego County and two (UCR1148 and UCR1149) from the Riverside County samples. The sequences were deposited in GenBank (HQ880579, JF758610, HQ880581, and HQ880582 and HQ880583, JF758611, HQ880585, and HQ880586 for the ITS regions and β-tubulin gene, respectively. ITS sequences for UCR1088 and UCR1101 had 98 and 100% match, respectively, to Eutypella spp. ITS sequences in GenBank (GQ293959 to GQ293961), while UCR1148 and UCR1149 matched 99% (GQ293956 to GQ293958). On the basis of morphological characteristics, UCR1088 and UCR1101 were similar to Eutypella spp. group 1, while UCR1148 and UCR1149 were similar to Eutypella spp. group 3 (4). Pathogenicity tests were conducted with all four isolates on detached shoots from healthy citrus trees of the same cultivar/rootstock from which each isolate was obtained. One wound per shoot was made on 1-year-old, green, detached shoots using a 3-mm-diameter cork borer and the wounded surfaces were inoculated with 3-mm-diameter mycelial plugs of 5-day-old cultures of each isolate growing on PDA-tet. Inoculated wounds and shoot ends were covered with petroleum jelly and wrapped with Parafilm (3). Control shoots were inoculated with sterile agar plugs. There were 10 inoculated shoots per isolate and noninoculated control treatment. Shoots were incubated at 25°C in moist chambers for 6 weeks. Lesions similar to those on the original infected shoots were observed on all inoculated shoots except the control treatment. Reisolation and identification of fungi from inoculated and control shoots were done using methods described above. Inoculated isolates were recovered from 100% of inoculated shoots but none was recovered from noninoculated shoots, indicating association of Eutypella spp. with citrus branch canker. To our knowledge, this is the first report of Eutypella spp. associated with cankers on citrus in California. References: (1) B. Piskur et al. Plant Dis. 91:1579, 2007. (2) B. Slippers et al. Mycologia 96:83, 2004. (3) F. P. Trouillas and W. D. Gubler. Plant Dis. 94:867, 2010. (4) F. P. Trouillas et al. Mycologia 102:319, 2010.

scholarly journals First Report of Curvularia lunata Causing Leaf Spot on Lotus in China

Plant Disease ◽  
2012 ◽  
Vol 96 (7) ◽  
pp. 1068-1068 ◽  
Author(s):  
R. Q. Cui ◽  
X. T. Sun
Keyword(s):  
Leaf Spot ◽  
Ethanol Solution ◽  
Jiangxi Province ◽  
Its2 Region ◽  
Curvularia Lunata ◽  
Commonwealth Mycological Institute ◽  
Conidial Suspension ◽  
First Report ◽  
Conidial State ◽  
Initial Symptoms

Lotus (Nelumbo nucifera Gaertn.) is a flowering aquatic plant, and is widely planted as a vegetable and ornamental plant in China. In June 2011, a leaf spot was observed on lotus in Pingxiang City of Jiangxi Province, causing approximately 60% of leaves to die and leading to 10 to 15% yield loss. Initial symptoms were purple-brown spots emerging on the leaf surfaces with diameters ranging from 0.5 to 3 cm, which later developed grayish white centers and a black-brown banding pattern on the edges. Lesions often merged to form large necrotic areas, covering more than 70% of the leaf surface, which may have contributed to plant death. Small pieces (5 mm2) of symptomatic leaves were excised from the junction of diseased and healthy tissue, surface sterilized in 70% ethanol solution for 1 min and 0.1% mercuric chloride solution for 5 min, washed in three changes of sterile distilled water, and transferred to potato dextrose agar plates. Cultures were maintained in an incubator at 25°C for 5 to 7 days. After 7 days, six black-brown colonies were isolated, which developed dark brown septate conidiophores. Conidia were 20 to 25 × 9 to 13 μm, with three-horizontal septa, and curved at the third cell from the base that was longer and darker than the others. Cells at each end were subhyaline and intermediate cells were medium brown. These characteristics were consistent with Curvularia lunata (Wakker) Boedijng (1,2,4). Molecular characterization was based on rDNA sequence. For two isolates, DNA was extracted using a CTAB protocol with 0.8% mercaptoethanol, then the ITS1-5.8S-ITS2 region was amplified with primers ITS1 (5′-TCCGTAGGTGAACCTGCGG-3′) and ITS4 (5′-TCCTCCGCTTATTGATATGC-3′) (3). PCR products were cloned and sequencing reactions were run on an AB3730 Stretch DNA sequencing system. On the basis of a comparison of 598 base pairs, both isolates had the same sequence (GenBank Accession No. JQ701798), which differed by one base pair from Cochliobolus lunatus NBRC 100173 (GenBank Accession No. JN943426) (conidial state: Curvularia lunata). Pathogenicity experiments were conducted by inoculating a conidial suspension (106 CFU/ml) on five newly matured leaves of healthy lotus. Plants inoculated with sterile water served as the noninoculated controls. Plants were incubated in the greenhouse at 20 to 25°C. All the inoculated leaves started showing disease symptoms (purple flecks) after 7 days and the noninoculated control plants remained asymptomatic. C. lunata was consistently recovered from all inoculated plants, except the control, thus fulfilling Koch's postulates. To our knowledge, this is the first report of leaf spot caused by C. lunata on lotus in China. References: (1) M. B. Ellis. Dematiaceous Hyphomycetes. Commonwealth Mycological Institute, Kew, Surrey, England, 1971. (2) M. M. Hawa, et al. Plant Dis. 93: 971, 2009. (3) K. J. Martin and P. T. Rygiewicz. BMC Microbiol. 5:28, 2005. (4) F. B. Rocha et al. Austral. Plant Pathol. 33: 601, 2004.

scholarly journals First Report of Corynespora Leaf Spot of Eucalyptus in China

Plant Disease ◽  
2015 ◽  
Vol 99 (3) ◽  
pp. 419-419 ◽  
Author(s):  
C. K. Phan ◽  
J. G. Wei ◽  
F. Liu ◽  
B. S. Chen ◽  
J. T. Luo ◽  
...  
Keyword(s):  
Leaf Spot ◽  
Southern China ◽  
Tap Water ◽  
Pathogenic Fungi ◽  
Leaf Spot Disease ◽  
Pathogenicity Test ◽  
Commonwealth Mycological Institute ◽  
Conidial Suspension ◽  
Single Spore ◽  
First Report

Eucalyptus is widely planted in the tropics and subtropics, and it has become an important cash crop in Southern China because of its fast-growing nature. In the Guangxi Province of southern China, Eucalyptus is produced on approximately 2 million ha, and two dominant asexual clones, Guanglin No. 9 (E. grandis × E. urophylla) and DH3229 (E. urophylla × E. grandis), are grown. Diseases are an increasing threat to Eucalyptus production in Guangxi since vast areas are monocultured with this plant. In June 2013, a leaf spot disease was observed in eight out of 14 regions in the province on a total of approximately 0.08 million ha of Eucalyptus. Initially, the lesions appeared as water-soaked dots on leaves, which then became circular or irregular shaped with central gray-brown necrotic lesions and dark red-brown margins. The size of leaf spots ranged between 1 and 3 mm in diameter. The main vein or small veins adjacent to the spots were dark. The lesions expanded rapidly during rainy days, producing reproductive structures. In severe cases, the spots coalesced and formed large irregular necrotic areas followed by defoliation. The causal fungus was isolated from diseased leaves. Briefly, the affected leaves were washed with running tap water, sterilized with 75% ethanol (30 s) and 0.1% mercuric dichloride (3 min), and then rinsed three times with sterilized water. Small segments (0.5 to 0.6 cm2) were cut from the leading edge of the lesions and plated on PDA. The plates were incubated at 25°C for 7 to 10 days. When mycelial growth and spores were observed, a single-spore culture was placed on PDA and grown in the dark at 25°C for 10 days. A pathogenicity test was done by spraying a conidial suspension (5 × 105 conidia ml–1) of isolated fungus onto 30 3-month-old leaves of Guanglin No. 9 seedlings. The plants were covered with plain plastic sheets for 7 days to keep the humidity high. Lesions similar to those observed in the forests were observed on the inoculated leaves 7 to 10 days after incubation. The same fungus was re-isolated. Leaves of control plants (sprayed with sterilized water) were disease free. Conidiophores of the fungus were straight to slightly curved, erect, unbranched, septate, and pale to light brown. Conidia were formed in chains or singly with 4 to 15 pseudosepta, which were oblong oval to cylindrical, subhyaline to pale olivaceous brown, straight to curved, 14.5 to 92.3 μm long, and 3.5 to 7.1 μm wide. The fungus was morphologically identified as Corynespora cassiicola (1). DNA of the isolate was extracted, and the internal transcribed spacer (ITS) region (which included ITS 1, 5.8S rDNA gene of rDNA, and ITS 2) was amplified with primers ITS5 and ITS4. 529 base pair (bp) of PCR product was obtained and sequenced. The sequence was compared by BLAST search to the GenBank database and showed 99% similarity to C. cassiicola (Accession No. JX087447). Our sequence was deposited into GenBank (KF669890). The biological characters of the fungus were tested. Its minimum and maximum growth temperatures on PDA were 7 and 37°C with an optimum range of 25 to 30°C. At 25°C in 100% humidity, 90% of conidia germinated after 20 h. The optimum pH for germination was 5 to 8, and the lethal temperature of conidia was 55°C. C. cassiicola has been reported causing leaf blight on Eucalyptus in India and Brazil (2,3) and causing leaf spot on Akebia trifoliate in Guangxi (4). This is the first report of this disease on Eucalyptus in China. References: (1) M. B. Ellis and P. Holliday. CMI Descriptions of Pathogenic Fungi and Bacteria, No. 303. Commonwealth Mycological Institute, Kew, Surrey, UK, 1971. (2) B. P. Reis, et al. New Dis. Rep. 29:7, 2014. (3) K. I. Wilson and L. R. Devi. Ind. Phytopathol. 19:393, 1966. (4) Y. F. Ye et al. Plant Dis. 97:1659, 2013.

scholarly journals First Report of Lasiodiplodia theobromae Causing Inflorescence Blight of Mango

Plant Disease ◽  
2013 ◽  
Vol 97 (10) ◽  
pp. 1380-1380 ◽  
Author(s):  
L. M. Serrato-Diaz ◽  
M. Perez-Cuevas ◽  
L. I. Rivera-Vargas ◽  
R. D. French-Monar
Keyword(s):  
Puerto Rico ◽  
Mangifera Indica ◽  
Fruit Rot ◽  
Its2 Region ◽  
Morphological Identification ◽  
Tropical Fruit ◽  
Lasiodiplodia Theobromae ◽  
First Report ◽  
Pure Cultures ◽  
Β Tubulin

Mango (Mangifera indica L.) is an important tropical fruit crop in Puerto Rico. During a disease survey from 2008 to 2010, inflorescence blight was observed at the Mango Germplasm Collection of the University of Puerto Rico's Experiment Station in Juana Diaz as a rotting of the rachis (main axis of the inflorescence), rachilla (lateral axis), and flowers. Diseased inflorescences from cultivars ‘Haden’ and ‘Irwin’ were disinfested with 70% ethanol, followed by 0.5% sodium hypochlorite, rinsed with sterile water, and transferred to acidified potato dextrose agar (APDA). Two isolates of Lasiodiplodia theobromae (Pat.) Griffon & Maubl. were isolated from symptomatic tissue and identified morphologically using a Botryosphaeriaceae taxonomic key (3). In APDA, colonies of L. theobromae had initial greenish gray aerial mycelia that turned dark brown with age. Pycnidia were uniloculate and dark brown to black in color. Conidiogenous cells were hyaline, cylindrical, and holoblastic. Immature conidia were subovoid to ellipsoid, apex rounded, truncate at the base, thick walled, hyaline and one-celled, becoming dark brown, two-celled with irregular longitudinal striations when mature. Conidia (n = 50) averaged 26.88 μm long by 12.98 μm wide. Genomic DNA was extracted from pure cultures using a Qiagen DNeasy Plant Mini Kit. PCR amplification of three genes was used to support morphological identification. DNA analysis of the ITS1-5.8S-ITS2 region, and fragments of both β-tubulin and elongation factor 1 alpha (EF1-α) genes were sequenced and compared using BLASTN with sequences available in GenBank. Accession numbers of gene sequences of L. theobromae from Puerto Rico submitted to GenBank were: KC631659 and KC631660 for ITS region; KC631651 and KC631652 for β-tubulin; and KC631655 and KC631656 for EF1α. For all genes used, sequences were 99 to 100% identical to reference isolate CBS164.96 of L. theobromae reported in GenBank. Pathogenicity tests were conducted on six random healthy non-detached mango inflorescences from cultivars Haden and Irwin. Inflorescences were inoculated with 5-mm mycelial disks from 8-day-old pure cultures grown in APDA and kept in a humid chamber using plastic bags for 8 days under field conditions. Untreated controls were inoculated with APDA disks only. The test was repeated twice. For both cultivars, isolates of L. theobromae caused inflorescence (rachis, rachilla, and flowers) blight, 8 days after inoculation. Inflorescences turned brown and profuse mycelial growth was observed on the inflorescences. Untreated controls were disease-free and no fungi were reisolated from tissue. L. theobromae was reisolated from diseased inflorescences, fulfilling Koch's postulates. Fungi in the family Botryosphaeriaceae have been associated with stem-end rot, fruit rot, branch dieback, blossom blight, and cankers on mango (1,2,4). Worldwide, L. theobromae has only been reported causing dieback, stem end rot and fruit rot in mango (1,2). To our knowledge, this is the first report of L. theobromae causing inflorescence blight in mango. References: (1) N. I. Hui-Fang et al. Botanical Stud. 53:467, 2012. (2) A. M. Ismail et al. Australas. Plant Pathol. 41:649, 2012. (3) 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 , 6 August 2013. (4) B. Slippers et al. Mycologia 97:99, 2005.

scholarly journals First Report of Botrytis cinerea Causing Leaf Spot of Aquilegia vulgaris in Japan

Plant Disease ◽  
2009 ◽  
Vol 93 (4) ◽  
pp. 425-425 ◽  
Author(s):  
M. Zhang ◽  
T. Tsukiboshi ◽  
I. Okabe
Keyword(s):  
United States ◽  
Botrytis Cinerea ◽  
Leaf Spot ◽  
Leaf Tissue ◽  
The United States ◽  
Plant Diseases ◽  
Its2 Region ◽  
Commonwealth Mycological Institute ◽  
First Report ◽  
Leaf Spots

European columbine, Aquilegia vulgaris L., Ranunculaceae, is an herbaceous flower widely used in gardens, parterres, and courtyards and is a traditional herbal plant. During the summer of 2008, leaf spots were observed on a plant cultivated along a roadside area in Nasushiobara, Tochigi, Japan. In some courtyards, the leaf spot affected more than 60% of the plants. Early symptoms appeared as small, round or elliptic, brown lesions on the leaves. Lesions expanded to 5 to 15 × 4 to 10 mm, irregular spots that were dark brown to black in the middle, with pale yellow-brown or purple-brown margins. In continuously wet or humid conditions, thick, gray mycelium and conidia appeared on the surface of leaf spots. Conidiophores were melanized at the base and hyaline near the apex, branched, and septated (approximately 3 mm × 16 to 18 μm). Conidia were hyaline, aseptate, ellipsoidal to obovoid, with a slightly protuberant hilum, and ranged from 9 to 14.5 × 5.5 to 6.5 μm. The pathogen was identified as Botrytis cinerea Pers.:Fr on the basis of morphology and sequence of ITS1-5.8s-ITS2 region of rDNA. The sequence (GenBank Accession No. FJ424510) exactly matched the sequences of two Botryotinia fuckeliana (anamorph Botrytis cinerea), (e.g., GenBank Accession Nos. AY686865 and FJ169666) (2). The fungus was isolated on potato dextrose agar (PDA) from a single conidium found on the symptomatic leaf tissue. Colonies of B. cinerea were first hyaline and later turned gray to black when the spores differentiated. Koch's postulates were performed with three whole plants of potted aquilegia. Leaves were inoculated with mycelia plugs harvested from the periphery of a 7-day-old colony; an equal number of plants were inoculated with the plugs of PDA medium only and served as controls. All plants were covered with plastic bags for 24 h to maintain high relative humidity and incubated at 25°C. After 8 days, all mycelium-inoculated plants showed symptoms identical to those observed on leaves from A. vulgaris infected in the field, whereas controls remained symptom free. Reisolation of the fungus from lesions on inoculated leaves confirmed that the causal agent was B. cinerea. B. cinerea has been previously reported on A. vulgaris in the United States and China (1,3). To our knowledge, this is the first report of leaf spots caused by B. cinerea on A. vulgaris in Japan. References: (1) Anonymous. Index of Plant Diseases in the United States. USDA Agric. Handb. No 165, 1960. (2) M. B. Ellis. Dematiaceous Hyphomycetes. Commonwealth Mycological Institute, Kew, England, 1971. (3) Z. Y. Zhang. Flora Fungorum Sinicorum. Vol. 26. Botrytis, Ramularia. Science Press, Beijing, 2006.

scholarly journals First Report of Corynespora Leaf Spot Caused by C. cassiicola on Golden Vicary Privet (Ligustrum × vicaryi) in China

Plant Disease ◽  
2013 ◽  
Vol 97 (8) ◽  
pp. 1113-1113 ◽  
Author(s):  
S. H. Wang ◽  
D. Zhao ◽  
J. J. Gao
Keyword(s):  
Leaf Spot ◽  
Sequence Similarity ◽  
Aqueous Suspension ◽  
Morphological Characteristics ◽  
Leaf Spot Disease ◽  
Its2 Region ◽  
Commonwealth Mycological Institute ◽  
Corynespora Cassiicola ◽  
Humid Atmosphere ◽  
First Report

Golden vicary privet (Ligustrum × vicaryi Rehd.), a hybrid between L. ovalifolium ‘Aureum’ Rehd. and L. vulgare L., is widely used as a landscape shrub for horticultural ornamentation. From 2009 to 2011, a leaf spot disease of L. × vicaryi was observed in the parks in Luoyang, Henan Province, China. Lesions were initially brown and punctiform, and with age the lesions turned into elliptic, subcircular to irregular and pale brown, faintly zonate, and depressed. Fully mature lesions were mostly irregular to circular, 5 to 15 mm in diameter, centers tan to dark brown, with reddish brown to reddish purple margins of varying width. The disease eventually caused substantial premature defoliation. After infected leaves were collected from parks and maintained in a humid atmosphere, a layer of black mold developed on the surface of the lesions. Conidiophores were cylindrical, straight to slightly curved, brown, unbranched (2 to 7 septa), and were 98.5 to 403.9 μm in length, 4.5 to 6.6 μm in width. Conidia were solitary or in short chains containing two to five spores, and were cylindrical or obclavate, straight or flexuose (3 to 19 pseudosepta), pale olivaceous brown or brown when mature, and were 78.8 to 315.2 μm in length by 5.3 to 12.3 μm in width. Morphological characteristics of the fungus were similar to those of Corynespora cassiicola (Berk. & Curt.) Wei (1). Lesions on leaves were excised, surface sterilized, and plated on potato dextrose agar (PDA) and incubated at 25°C for 2 to 3 days. A fungus was isolated from the lesions, and pure isolates that were obtained after from single spored isolates were cultured on PDA. Colonies on PDA formed concentric growth rings, abundant aerial mycelia, and were grey or dark brown in color. The isolate ST1 was selected as a representative for molecular identification. The ITS1-5.8S-ITS2 region of the isolate was amplified by PCR with primers ITS1/ITS4 (3) and sequenced. BLAST analysis of the 559 bp amplicon (GenBank Accession No. KC138855) indicated 100% sequence similarity with C. cassiicola (GU138988) (2). To validate Koch's postulates, pathogenicity tests were performed by spraying leaves of five healthy potted L. vicaryi with a 106 conidia per ml aqueous suspension. Control plants were inoculated with sterile water. Plants were covered with plastic bags for 24 h after inoculation and maintained at 25°C. After 3 days, all inoculated plants showed typical symptoms, whereas water sprayed controls remained healthy. C. cassiicola was consistently reisolated from these lesions. The reisolated conidia showed the same morphological characteristics as described above. To our knowledge, this is the first report of leaf spot caused by C. cassiicola on L. × vicaryi in China. Its confirmation is a significant step toward management recommendations for growers. References: (1) M. B. Ellis et al. Corynespora cassiicola. CMI Descriptions of Pathogenic Fungi and Bacteria, no. 303. Commonwealth Mycological Institute, Kew, UK, 1971. (2) X. B. Liu et al. Plant Dis. 94:916, 2010. (3) T. J. White et al. Page 315 in: PCR Protocols: A Guide to Methods and Applications. Academic Press, San Diego, 1990.

scholarly journals First Report of Diaporthe pseudomangiferae Causing Inflorescence Rot, Rachis Canker, and Flower Abortion of Mango

Plant Disease ◽  
2014 ◽  
Vol 98 (7) ◽  
pp. 1004-1004 ◽  
Author(s):  
L. M. Serrato-Diaz ◽  
L. I. Rivera-Vargas ◽  
R. D. French-Monar
Keyword(s):  
Dna Analysis ◽  
Mangifera Indica ◽  
Germplasm Collection ◽  
Its2 Region ◽  
Post Inoculation ◽  
Tropical Fruit ◽  
First Report ◽  
Flower Abortion ◽  
Wide Range ◽  
Β Tubulin

Although mango (Mangifera indica L.) is a very important tropical fruit crop, limited studies have been conducted on fungal pathogens affecting the inflorescences. During a disease survey conducted from 2008 to 2010, 50% of the inflorescences were affected with inflorescence rot, rachis canker, and flower abortion characterized by blackening of plant tissue with soft rot lesions and suken lesions on the rachis, respectively. Symptoms were observed at the Mango Germplasm Collection of the University of Puerto Rico's Experiment Station in Juana Diaz, Puerto Rico. Five diseased pieces of 350 inflorescences from cvs. Haden and Irwin were disinfested with 70% ethanol, followed by 0.5% sodium hypochlorite, rinsed with sterile water, and transferred to acidified potato dextrose agar (APDA). Among several typical or common fungi, three isolates of Diaporthe pseudomangiferae (Dp) R.R. Gomes, C. Glienke & Crous were obtained from symptomatic tissue and identified morphologically using taxonomic keys and DNA sequence comparisons (1,2). On APDA, colonies of Dp initially had white-gray moderate aerial mycelia. Pycnidia were black and superficial on cultures with a central ostiole that exuded beige to light orange conidial droplets. Alpha conidia (n = 50) were aseptate, hyaline, smooth, fusiform, apex rounded and base truncate, averaged 7.34 μm long by 2.60 μm wide. Beta conidia (n = 50) were spindle-shaped, aseptate, hyaline and smooth, averaged 22.03 μm long by 1.53 μm wide. DNA analysis of the ITS1-5.8S-ITS2 region using primers ITS5 and ITS4, and fragments of both β-tubulin and translation elongation factor 1 alpha (EF1-α) genes using primers T1 and Bt2b, and EF1-728F and EF1-986R, respectively, were sequenced and compared using BLASTn with sequences available in the GenBank. Accession numbers of gene sequences of Dp submitted to GenBank were KF616498 to KF616500 for ITS region, KF616501 to KF616503 for β-tubulin, and KF616504 to KF616506 for EF1-α. For all genes used, sequences were 99 to 100% identical to reference isolate CBS 388.89 of Dp in GenBank. For each fungal isolate, pathogenicity tests were conducted on six random healthy non-detached mango inflorescences for both cvs. Haden and Irwin. Inflorescences were inoculated with 5-mm mycelial disks from 8-day-old pure cultures grown on APDA and kept in a humid chamber using plastic bags for 8 days under field conditions. Untreated controls were inoculated with APDA disks only. The test was repeated twice. On cv. Haden, isolates of Dp caused rachis canker (sunken lesion on the rachis) at 8 days post inoculation (dpi). On cv. Irwin, isolates of Dp caused inflorescence rot. Initially, white mycelia was observed on inflorescences but eventually inflorescences turned brown and flower abortion was observed at 8 dpi. Untreated controls did not show any of the above symptoms and no fungi were re-isolated from tissue. From diseased inflorescences, Dp was re-isolated, thus fulfilling Koch's postulates. Diaporthe spp. have been associated with fruit rots, stem cankers, decay, and wilt on a wide range of plant hosts (3,4). Recently, Dp was associated with fruit peel of mango in Mexico and the Dominican Republic (2). To our knowledge, this is the first report of Dp causing inflorescence rot, rachis canker, and flower abortion in mango. References: (1) H. L. Barnett and B. B. Hunter. Illustrated Genera of Imperfect Fungi. APS Press. St. Paul, MN, 1998. (2) R. R. Gomes et al. Persoonia. 31:1, 2013. (3) J. M. Santos et al. Persoonia 27:9, 2011. (4) S. M. Thompson et al. Persoonia 27:80, 2011.

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