scholarly journals First Report of Lentil Ascochyta Blight Caused by Ascochyta lentis in Italy

Plant Disease ◽  
1999 ◽  
Vol 83 (1) ◽  
pp. 77-77
Author(s):  
C. Cappelli ◽  
R. Buonaurio ◽  
R. Torricelli
Keyword(s):  
Lens Culinaris ◽  
Ascochyta Blight ◽  
Central Italy ◽  
Morphological Characteristics ◽  
Potato Dextrose Agar ◽  
Conidial Suspension ◽  
First Report ◽  
Ascochyta Lentis ◽  
Humidity Chamber ◽  
Dry Conditions

In May 1997, ascochyta blight incited by Ascochyta lentis Vassiljevsky was observed at an incidence of less than 5% in lentil (Lens culinaris Medik.) fields in Umbria (Central Italy). Symptoms appeared on leaves and stems as tan spots surrounded by a dark margin. Small black pycnidia that produced a pink exudate containing hyaline, 1 septate, 14.2 to 15.8 × 3.5 μm conidia under high humidity were visible in the center of the spots. The fungus was consistently isolated on potato dextrose agar from diseased leaves or stems. To satisfy Koch's postulates, a conidial suspension (106 conidia per ml) of the fungus was sprayed on leaves of 20-day-old lentil plants (landrace Castelluccio) that were maintained in a humidity chamber for 96 h after inoculation. Lesions resembling symptoms that occurred in the field were observed on plants 3 weeks after inoculation. Symptoms were not observed on control plants sprayed with water. The fungus reisolated from the diseased plants was identical to the original isolates. Based on morphological characteristics of pycnidia and conidia as well as pathogenicity, the fungus was identified as A. lentis. A deep-freeze blotter method (2) was used to detect A. lentis in lentil seeds of 20 local landraces used by Umbrian farmers and two accessions from Canada and Turkey, as well as in seed collected from infected fields. The fungus was present only in the two lentil accessions with an incidence of about 5%. Although the fungus had been isolated from Italian seed germplasm in 1986 (1), this is the first report of ascochyta blight occurring in lentil crops in Italy. The heavy rainfalls that characterize the first stage of lentil cultivation in Umbria are favorable for disease development while hot and dry conditions that usually occur during flowering and maturation prevent the dissemination of inoculum and the infection of the seeds. For these reasons, some Umbrian areas could be more suitable for production of ascochyta-free lentil seeds. References: (1) W. J. Kaiser and R. M. Hannan. Phytopathology 76:355, 1986. (2) T. Limonard. Proc. Int. Seed Test. Assoc. 33:343, 1968.

scholarly journals First Report of Colletotrichum gloeosporioides on Chinese Rose in Argentina

Plant Disease ◽  
2000 ◽  
Vol 84 (12) ◽  
pp. 1345-1345 ◽  
Author(s):  
M. C. Rivera ◽  
E. R. Wright ◽  
S. Carballo
Keyword(s):  
Colletotrichum Gloeosporioides ◽  
Buenos Aires ◽  
Morphological Characteristics ◽  
Disease Prevalence ◽  
Potato Dextrose Agar ◽  
Conidial Suspension ◽  
First Report ◽  
Hibiscus Rosa Sinensis ◽  
Leaf Drop ◽  
Stems And Leaves

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

scholarly journals First Report of Ascochyta rabiei Causing Ascochyta Blight of Chickpea in Argentina

Plant Disease ◽  
2012 ◽  
Vol 96 (9) ◽  
pp. 1375-1375 ◽  
Author(s):  
G. Viotti ◽  
M. A. Carmona ◽  
M. Scandiani ◽  
A. N. Formento ◽  
A. Luque
Keyword(s):  
Disease Incidence ◽  
Ascochyta Blight ◽  
Morphological Characteristics ◽  
Pathogenic Fungi ◽  
Ascochyta Rabiei ◽  
Infected Leaf ◽  
Buenos Aires Province ◽  
Conidial Suspension ◽  
First Report ◽  
Plastic Bags

In November 2011, lesions similar to those reported for Ascochyta blight (1) were observed on Cicer arietinum L. (chickpea) plants growing in three commercial fields located at Río Primero and Río Segundo (Cordoba Province) and Lobería (Buenos Aires Province), Argentina. Disease incidence (percentage of plants affected) was 100% in all fields surveyed. Plants showed leaves, petioles, stems, and pods with brown lesions. Symptoms on leaves and pods were circular to oval (2 to 14 mm) while in the stems the lesions were elongated (2 to 30 mm). Seeds appeared small and shriveled with brown discoloration. Morphology of the fungi was examined on infected tissues. Numerous black pycnidia measuring 94.6 to 217.9 μm (145.9 ± 28.8 μm), arranged in concentric rings, were observed within of all the lesions. Conidia were predominantly aseptate, straight, hyaline with blunt ends, and measured 9.3 to 12.9 (11.3 ± 1.12) × 3.3 to 5.0 μm (4.2 ± 0.51). Morphological characteristics of the pathogen were similar to those described for Ascochyta rabiei (Pass.) Labrousse (teleomorph Didymella rabiei (Kovacheski) v. Arx (= Mycosphaerella rabiei Kovacheski)) (2). Fungus from infected leaf tissues was isolated on potato dextrose agar. Pathogenicity tests were conducted on seedlings of the susceptible cultivar by spraying leaves of each of 100 seedling plants with 10 ml of a conidial suspension (2 × 104 conidia/ml) of the isolated pathogen with a handheld atomizer. Plants were covered with plastic bags and placed in a growing chamber at 20 to 25°C for 3 days. The plastic bags were removed and the plants were maintained in high humidity at the same temperature. Noninoculated plants were used as controls. After 5 days, all inoculated plants showed typical symptoms. Foliar and stem lesions symptoms were similar to those originally observed in the field. Control plants remained healthy. Koch's postulates were fulfilled by isolating A. rabiei from inoculated plants. The colonies and the morphology of conidia were the same as those of the original isolates. To our knowledge, this is the first report of A. rabiei infecting chickpeas in Argentina. The outbreak of Ascochyta blight in Argentina is of concern because of its severity and the possibility that the pathogen was introduced on seed. This report underscores the need for further research on effective management programs for Ascochyta blight. References: (1) B. Bayaa and W. Chen. Compendium of Chickpea and Lentil Diseases and Pests The American Phytopathological Society, St. Paul, MN, 2011. (2) E. Punithalingam and P. Holliday. Page 337 in: CMI Descriptions of Pathogenic Fungi and Bacteria. CMI, Kew, Surrey, UK, 1972.

scholarly journals First Report of Septoria Blight of Parsley Caused by Septoria petroselini in the Mediterranean Region of Turkey

Plant Disease ◽  
2003 ◽  
Vol 87 (1) ◽  
pp. 99-99 ◽  
Author(s):  
S. Kurt
Keyword(s):  
Mediterranean Region ◽  
Morphological Characteristics ◽  
Potato Dextrose Agar ◽  
Distilled Water ◽  
Conidial Suspension ◽  
Sterile Water ◽  
First Report ◽  
Foliar Symptoms ◽  
Polyethylene Bags ◽  
The Mediterranean

During December 2001 to March 2002, Septoria blight of parsley was observed in approximately 500 ha of commercial parsley crops in Arsuz County, Hatay, in the Mediterranean Region of Turkey. Incidence of disease ranged from 42 to 80%. Symptoms included irregularly shaped, grayish brown spots (average 3 to 8 mm diameter) with a slightly darker brown margin of necrotic tissue that developed into tan-to-brown lesions surrounded by chlorotic halo on the leaves. Oval-shaped lesions were observed occasionally on petioles. Lesions contained erumpent, dark brown, flask-shaped pycnidia with the ostiole on the upper surface of the foliage. Thirty samples, consisting of diseased leaves and petioles of parsley, were collected from each field. Infected tissues were surface-sterilized in 1% NaOCl for 2 min, rinsed in sterile distilled water, placed on petri dishes containing potato dextrose agar (PDA), and incubated for 10 to 14 days at 25°C. The fungus formed long, multiseptate (0 to 4), hyaline, filiform conidia (14 to 29 μm × 0.5 to 1.9 μm), and short conidiophores within the pycnidia. Based on the morphological characteristics of the fungus, the pathogen was identified as Septoria petroselini Desm. (1). Monoconidial cultures of 18 isolates were prepared. Pathogenicity was confirmed by brush-inoculating slightly wounded foliage of 5- to 7- week-old parsley plants (cv. Kereviz yapragi) with a conidial suspension (106 conidia per ml of sterile water) of each isolate of S. petroselini. Control plants that were brush-inoculated with distilled water and inoculated plants were placed in clear polyethylene bags that were closed and incubated at 20°C for 48 h. The bags were removed, and plants were maintained in a dew chamber for 21 days at 65 to 70% relative humidity. Foliar symptoms developed 15 days after inoculation and appeared similar to lesions observed in the field. Yellowing and necrosis of leaves was also observed on >60% of inoculated plants. No lesions developed on the control plants. The pathogen was readily reisolated on PDA from inoculated plants. To our knowledge, this is the first report of Septoria blight of parsley in the Mediterranean Region of Turkey. Reference: (1) R. F. Cerkauskas and J. Uyenaka. Plant Dis. 74:1037, 1990.

scholarly journals First Report of Leaf Blight on Sweet Persimmon Tree by Pestalotiopsis theae in Spain

Plant Disease ◽  
1999 ◽  
Vol 83 (11) ◽  
pp. 1070-1070 ◽  
Author(s):  
J. J. Tuset ◽  
C. Hinarejos ◽  
J. L. Mira
Keyword(s):  
Morphological Characteristics ◽  
Climatic Conditions ◽  
Leaf Blight ◽  
Diospyros Kaki ◽  
Conidial Suspension ◽  
Basal Cells ◽  
First Report ◽  
Dry Conditions ◽  
Agar Media ◽  
Grey Blight

During July 1998, a leaf blight caused by Pestalotiopsis theae (Saw.) Stey. was observed at an incidence of 18 to 20% in sweet persimmon (Diospyros kaki L.fil.) orchards in Huelva Province (southwestern Spain). Symptoms appeared on leaves as large grayish brown circular ringspots. Usually, they were solitary, but occasionally, two to three spots occurred on an affected leaf. In severe cases, lesions developed on more than one-third of the leaf, resulting in defoliation. Small black acervular conidiomata were visible in the surface of spots. These conidiomata produced fusiform conidia that were straight or rarely curved, four five-celled euseptate, including three olivaceous or dark brown median cells, and hyaline apical and basal cells with appendages that were slightly constricted at septa. Conidiomata were up to 240 μm in diameter; conidiogenous cells were 6 to 13 × 1.2 to 2.8 μm; conidia were 24.7 × 7.8 μm; three median cells were 16.7 μm long; two to three apical appendages (rarely four) were 28.3 μm long; and straight basal appendage was 5.7 μm. P. theae was consistently isolated on potato dextrose agar from diseased leaves and conidiomata. To confirm pathogenicity, both mycelial plugs and a conidial suspension (1.5 × 106 conidia per ml) of the fungus were used as inocula. Young completely developed leaves from persimmon tree cvs. Sharon and Hanafuyu were inoculated in the laboratory and maintained in a moist chamber for 5 days. Lesions resembling symptoms that occurred in the field were observed on leaves after 5 days. Symptoms were not observed on control leaves inoculated with agar media or sprayed with water. The fungus reisolated from diseased leaves was identical to the original isolates. Based on the morphological characteristics of conidiomata and conidia as well as pathogenicity, the fungus was identified as P. theae (1). This is the first report of this fungus as a pathogen of D. kaki in Europe. Possibly the introduction of P. theae to Spain has been through young imported persimmon plants. Unusual climatic conditions (heavy rainfalls during 1997 in southwestern Spain) have been favorable for disease development. The hot and dry conditions that usually occur during flowering, growing, and maturation of persimmon fruits normally prevent dissemination of inoculum and infection of leaves. For these reasons, the wet areas of southwestern Spain could be more favorable for “grey blight” of persimmon trees. Reference: (1) T.-H. Chang et al. Korean J. Plant Pathol. 12:377, 1996.

scholarly journals First Report of Azalea Petal Blight Caused by Pestalotiopsis guepini in Argentina

Plant Disease ◽  
2000 ◽  
Vol 84 (1) ◽  
pp. 100-100 ◽  
Author(s):  
M. C. Rivera ◽  
E. R. Wright
Keyword(s):  
Buenos Aires ◽  
Morphological Characteristics ◽  
Potato Dextrose Agar ◽  
Commonwealth Mycological Institute ◽  
Conidial Suspension ◽  
Koch’S Postulates ◽  
First Report ◽  
Pure Cultures ◽  
Pathogenicity Testing ◽  
Koch's Postulates

The most important azalea (Rhododendron spp.) growing area in Argentina is located in the outskirts of Buenos Aires. A disease of the azalea flower was detected during surveys conducted during September 1998. Irregular brown spots were uniformly distributed on petals and resulted in a flower blight that did not lead to abscission of petals. Pieces of infected petals were surface-sterilized for 1 min in 2% NaOCl, plated on potato dextrose agar, and incubated at 24 ± 2°C. Pure cultures were identified as Pestalotiopsis guepini (Desmaz.) Steyaert (synamorph P. guepini Desmaz.) based on morphological characteristics (1,2). Inoculation for pathogenicity testing was carried out by spraying a conidial suspension (1 × 106 conidia per ml) on plants with previously punctured petals. Inoculated plants with unwounded flowers, as well as noninoculated controls, were included. Plants were incubated in moist chambers at 24°C. Symptoms appeared on all punctured flowers within 4 to 5 days. Petals were blighted by 9 days after inoculation and were covered with black acervuli by 12 days after inoculation. Unwounded and noninoculated controls remained symptomless. The pathogen was reisolated from inoculated flowers, completing Koch's postulates. Pathogenicity of P. guepini on azalea leaves in Argentina was reported in 1991. This is the first report of P. guepini causing disease on azalea flowers in Argentina. References: (1) J. E. M. Mordue. CMI Descr. Pathog. Fungi Bact. No. 320, 1971. (2) B. C. Sutton. 1980. The Coelomycetes. Commonwealth Mycological Institute, Kew, England.

scholarly journals First Report of Alternaria alternata as a Dieback Pathogen of Kiwifruit

Plant Disease ◽  
2000 ◽  
Vol 84 (3) ◽  
pp. 371-371 ◽  
Author(s):  
P. C. Tsahouridou ◽  
C. C. Thanassoulopoulos
Keyword(s):  
Alternaria Alternata ◽  
Morphological Characteristics ◽  
Potato Dextrose Agar ◽  
Conidial Suspension ◽  
Actinidia Chinensis ◽  
Northern Greece ◽  
Disease Symptoms ◽  
First Report ◽  
Surface Sterilization ◽  
Pathogenicity Tests

During a survey of diseases on kiwifruit (Actinidia chinensis) cv. Hayward during spring 1998 in Northern Greece, leaves of kiwifruit trees were found covered with small, necrotic brown spots. Intense spotting was associated with defoliation. Furthermore, small, sunken, dark brown cankers appeared a few centimeters below the twig tip, and twigs died distal to the canker a few days later, while the twig remained healthy below the canker, often producing a new shoot below the canker. Isolations from symptomatic leaves and internal tissues of twigs on potato dextrose agar (PDA), after surface-sterilization with 0.5% NaOCl and 90% alcohol, respectively, consistently yielded a fungus that, based on conidial morphological characteristics, was identified as Alternaria alternata (Nees:Fr.) Keissl. (2). Pathogenicity tests were performed on 3-year-old kiwi plants. Tests on twigs were conducted by inoculating 35 twigs with 5-mm disks from 7-day-old cultures on PDA at 25°C. Each twig was inoculated with three disks. Tests on leaves were conducted by spraying a conidial suspension (5 × 106 conidia per ml) of the cultures on leaves. Plants were kept in a glasshouse at 22 to 25°C. Symptoms, identical to those observed in the field, developed on leaves and twigs 6 and 18 days, respectively, after inoculation. All inoculated leaves exhibited symptoms of the disease, whereas more than 95% of inoculated twigs exhibited disease symptoms. A. alternata was consistently reisolated from inoculated tissues. A. alternata is widely known to be a leaf spot pathogen of kiwifruit (1). This is the first report of A. alternata causing twig dieback. References: (1) L. Corazza and L. Luongo. Plant Dis. 83:487, 1999. (2) E. G. Simmons. Mycotaxon 37:79, 1990.

scholarly journals First Report of Leaf Blight of Japanese Yew Caused by Pestalotiopsis microspora in Korea

Plant Disease ◽  
2014 ◽  
Vol 98 (5) ◽  
pp. 691-691 ◽  
Author(s):  
Y. H. Jeon ◽  
W. Cheon
Keyword(s):  
Dna Sequences ◽  
Apical Cell ◽  
Morphological Characteristics ◽  
Leaf Blight ◽  
Economic Damage ◽  
Leaf Margin ◽  
Conidial Suspension ◽  
First Report ◽  
Pestalotiopsis Microspora ◽  
Large Trees

Worldwide, Japanese yew (Taxus cuspidata Sieb. & Zucc.) is a popular garden tree, with large trees also being used for timber. In July 2012, leaf blight was observed on 10% of Japanese yew seedling leaves planted in a 500-m2 field in Andong, Gyeongsangbuk-do Province, South Korea. Typical symptoms included small, brown lesions that were first visible on the leaf margin, which enlarged and coalesced into the leaf becoming brown and blighted. To isolate potential pathogens from infected leaves, small sections of leaf tissue (5 to 10 mm2) were excised from lesion margins. Eight fungi were isolated from eight symptomatic trees, respectively. These fungi were hyphal tipped twice and transferred to potato dextrose agar (PDA) plates for incubation at 25°C. After 7 days, the fungi produced circular mats of white aerial mycelia. After 12 days, black acervuli containing slimy spore masses formed over the mycelial mats. Two representative isolates were further characterized. Their conidia were straight or slightly curved, fusiform to clavate, five-celled with constrictions at the septa, and 17.4 to 28.5 × 5.8 to 7.1 μm. Two to four 19.8- to 30.7-μm-long hyaline filamentous appendages (mostly three appendages) were attached to each apical cell, whereas one 3.7- to 7.1-μm-long hyaline appendage was attached to each basal cell, matching the description for Pestalotiopsis microspora (2). The pathogenicity of the two isolates was tested using 2-year-old plants (T. cuspidata var. nana Rehder; three plants per isolate) in 30-cm-diameter pots filled with soil under greenhouse conditions. The plants were inoculated by spraying the leaves with an atomizer with a conidial suspension (105 conidia/ml; ~50 ml on each plant) cultured for 10 days on PDA. As a control, three plants were inoculated with sterilized water. The plants were covered with plastic bags for 72 h to maintain high relative humidity (24 to 28°C). At 20 days after inoculation, small dark lesions enlarged into brown blight similar to that observed on naturally infected leaves. P. microspora was isolated from all inoculated plants, but not the controls. The fungus was confirmed by molecular analysis of the 5.8S subunit and flanking internal transcribed spaces (ITS1 and ITS2) of rDNA amplified from DNA extracted from single-spore cultures, and amplified with the ITS1/ITS4 primers and sequenced as previously described (4). Sequences were compared with other DNA sequences in GenBank using a BLASTN search. The P. microspora isolates were 99% homologous to other P. microspora (DQ456865, EU279435, FJ459951, and FJ459950). The morphological characteristics, pathogenicity, and molecular data assimilated in this study corresponded with the fungus P. microspora (2). This fungus has been previously reported as the causal agent of scab disease of Psidium guajava in Hawaii, the decline of Torreya taxifolia in Florida, and the leaf blight of Reineckea carnea in China (1,3). Therefore, this study presents the first report of P. microspora as a pathogen on T. cuspidata in Korea. The degree of pathogenicity of P. microspora to the Korean garden evergreen T. cuspidata requires quantification to determine its potential economic damage and to establish effective management practices. References: (1) D. F. Farr and A. Y. Rossman, Fungal Databases, Syst. Mycol. Microbiol. Lab. Retrieved from http://nt.ars-grin.gov/fungaldatabases/ (2) L. M. Keith et al. Plant Dis. 90:16, 2006. (3) S. S. N. Maharachchikumbura. Fungal Diversity 50:167, 2011. (4) T. J. White et al. PCR Protocols. Academic Press, San Diego, CA, 1990.

scholarly journals First report of banana (Musa acuminate L. AAA Cavendish, cv. Formosana) leaf spot disease caused by Curvularia geniculata in China

Plant Disease ◽  
2021 ◽  
Author(s):  
Yanxiang Qi ◽  
Yanping Fu ◽  
Jun Peng ◽  
Fanyun Zeng ◽  
Yanwei Wang ◽  
...  
Keyword(s):  
Leaf Spot ◽  
Disease Incidence ◽  
Morphological Characteristics ◽  
Universal Primers ◽  
Leaf Spot Disease ◽  
Leaf Margin ◽  
Conidial Suspension ◽  
Tropical Fruit ◽  
First Report ◽  
Spot Disease

Banana (Musa acuminate L.) is an important tropical fruit in China. During 2019-2020, a new leaf spot disease was observed on banana (M. acuminate L. AAA Cavendish, cv. Formosana) at two orchards of Chengmai county (19°48ʹ41.79″ N, 109°58ʹ44.95″ E), Hainan province, China. In total, the disease incidence was about 5% of banana trees (6 000 trees). The leaf spots occurred sporadically and were mostly confined to the leaf margin, and the percentage of the leaf area covered by lesions was less than 1%. Symptoms on the leaves were initially reddish brown spots that gradually expanded to ovoid-shaped lesions and eventually become necrotic, dry, and gray with a yellow halo. The conidia obtained from leaf lesions were brown, erect or curved, fusiform or elliptical, 3 to 4 septa with dimensions of 13.75 to 31.39 µm × 5.91 to 13.35 µm (avg. 22.39 × 8.83 µm). The cells of both ends were small and hyaline while the middle cells were larger and darker (Zhang et al. 2010). Morphological characteristics of the conidia matched the description of Curvularia geniculata (Tracy & Earle) Boedijn. To acquire the pathogen, tissue pieces (15 mm2) of symptomatic leaves were surface disinfected in 70% ethanol (10 s) and 0.8% NaClO (2 min), rinsed in sterile water three times, and transferred to potato dextrose agar (PDA) for three days at 28°C. Grayish green fungal colonies appeared, and then turned fluffy with grey and white aerial mycelium with age. Two representative isolates (CATAS-CG01 and CATAS-CG92) of single-spore cultures were selected for molecular identification. Genomic DNA was extracted from the two isolates, the internal transcribed spacer (ITS), large subunit ribosomal DNA (LSU rDNA), glyceraldehyde-3-phosphate dehydrogenase (GAPDH), translation elongation factor 1-alpha (TEF1-α) and RNA polymerase II second largest subunit (RPB2) were amplified and sequenced with universal primers ITS1/ITS4, LROR/LR5, GPD1/GPD2, EF1-983F/EF1-2218R and 5F2/7cR, respectively (Huang et al. 2017; Raza et al. 2019). The sequences were deposited in GenBank (MW186196, MW186197, OK091651, OK721009 and OK491081 for CATAS-CG01; MZ734453, MZ734465, OK091652, OK721100 and OK642748 for CATAS-CG92, respectively). For phylogenetic analysis, MEGA7.0 (Kumar et al. 2016) was used to construct a Maximum Likelihood (ML) tree with 1 000 bootstrap replicates, based on a concatenation alignment of five gene sequences of the two isolates in this study as well as sequences of other Curvularia species obtained from GenBank. The cluster analysis revealed that isolates CATAS-CG01 and CATAS-CG92 were C. geniculata. Pathogenicity assays were conducted on 7-leaf-old banana seedlings. Two leaves from potted plants were stab inoculated by puncturing into 1-mm using a sterilized needle and placing 10 μl conidial suspension (2×106 conidia/ml) on the surface of wounded leaves and equal number of leaves were inoculated with sterile distilled water serving as control (three replicates). Inoculated plants were grown in the greenhouse (12 h/12 h light/dark, 28°C, 90% relative humidity). Necrotic lesions on inoculated leaves appeared seven days after inoculation, whereas control leaves remained healthy. The fungus was recovered from inoculated leaves, and its taxonomy was confirmed morphologically and molecularly, fulfilling Koch’s postulates. C. geniculata has been reported to cause leaf spot on banana in Jamaica (Meredith, 1963). To our knowledge, this is the first report of C. geniculata on banana in China.

scholarly journals First Report of Spot Blotch Caused by Bipolaris sorokiniana on Winter Rye in Kentucky

Plant Disease ◽  
2021 ◽  
Author(s):  
Danilo Neves ◽  
Bill Bruening ◽  
Carrie A Knott ◽  
Chad Lee ◽  
Carl Bradley
Keyword(s):  
Flag Leaf ◽  
Morphological Characteristics ◽  
Bipolaris Sorokiniana ◽  
Spot Blotch ◽  
Winter Rye ◽  
Glycerol Solution ◽  
Conidial Suspension ◽  
Potential Yield ◽  
First Report ◽  
Plastic Bag

The Kentucky distilling industry ranks as one of the state’s largest industries and continues to expand. In 2017, the Kentucky distilling industry was responsible for approximately $235 million in state and local tax revenues (Coomes and Kornstein, 2019). Rye (Secale cereale L.) grains are a vital component for production of some distilled spirits. Although winter rye is produced on relatively few hectares in Kentucky currently, a recent initiative has supported expanding production to help meet the growing demand of local distilleries. University of Kentucky winter rye research field trials were visited in Caldwell and Logan Counties, KY in May 2018, and in Fayette County, KY in May 2019. Leaves were collected that had dark brown, oval to irregular-shaped lesions with definite margins and yellow halos. Symptoms were present on approximately 50% to 80% of the flag leaves, with severity ranging from 5% to 30% of the flag leaf area affected. Leaves were surface-disinfested by soaking in a 2% NaOCl solution for 1 min and rinsed twice in sterilized water and then placed in a humidity chamber (plastic bag with moist paper towels) at room temperature (approximately 24°C) to induce fungal sporulation. Seventeen single-spore isolates were obtained and stored at -80°C in 15% glycerol solution. Isolates were grown on potato dextrose agar under 12 h cycles of white light/darkness for 5 days. Colonies were gray to black. Conidia that formed were mostly straight or slightly curved, dark olivaceous brown, 3-7 septate, and 41.0-90.4 × 15.2-29.3 µm. Based on the symptoms observed on the collected leaves and these morphological characteristics similar to those described by Chang and Hwang (2000) and Manamgoda et al. (2014), the fungus was tentatively identified as Bipolaris sorokiniana (Sorokin) Shoemaker. The sequence of internal transcribed spacer regions (ITS) and glyceraldehyde 3-phosphate dehydrogenase (GAPDH) were used to identify three isolates (18Bs004, 18Bs111 and 19Bs064) using primer ITS1/ITS4 (White et al. 1990) and GPD1/GPD2 (Berbee et al. 1999), respectively. The sequences were deposited in GenBank with accession numbers MT457817, MT457818 and MZ066635 for ITS sequences and MZ073644 to MZ073646 for GAPDH sequences. BLAST searches with ITS and GAPDH sequences matched 100% identity (344/344 bp and 515/515 bp for ITS and GAPDH sequences, respectively) to B. sorokiniana (GenBank accession No. MT254731 and MH844813, respectively). To prove pathogenicity, a conidial suspension (1 × 105 conidia/ml) was used to inoculate 15-day-old cultivar ‘Serafino’ winter rye plants in the greenhouse. Leaves of 8 plants were inoculated with 50 ml of the conidial suspension using a spray bottle. Plants were covered with a transparent plastic bag for 48 h, and symptoms were observed 10 days after inoculation. Leaf lesions, similar to those described above, were present on all inoculated plants, but no symptoms were observed on non-inoculated control plants. Bipolaris sorokiniana was reisolated from symptomatic leaves and the identity of the pathogen was confirmed based on the morphology previously described. To our knowledge, this is the first report of spot blotch caused by B. sorokiniana on winter rye in Kentucky, but B. sorokiniana has been reported on rye in the neighboring state of Virginia (Roane 2009). Kentucky produces approximately 150,000 and 4,000 ha of winter wheat (Triticum aestivum) and winter barley (Hordeum vulgare) annually, respectively, which are both known hosts of B. sorokiniana (Kumar et al. 2002). An isolate of B. sorokiniana from rye was reported by Ghazvini and Tekauz (2007) to be less virulent on barley differential lines. Further research is needed to better understand spot blotch distribution, susceptibility in winter rye cultivars, and potential yield and quality loss implications in winter rye production and end use. It is unknown how susceptible various winter rye cultivars grown in Kentucky are to spot blotch.

scholarly journals First Report of Occurrence of Eggplant Wilt Caused by Verticillium dahliae in Korea

Plant Disease ◽  
2000 ◽  
Vol 84 (10) ◽  
pp. 1152-1152
Author(s):  
S. K. Kim ◽  
S. S. Hong ◽  
K. W. Kim ◽  
E. W. Park
Keyword(s):  
Verticillium Dahliae ◽  
Solanum Melongena ◽  
Morphological Characteristics ◽  
Wilt Disease ◽  
Potato Dextrose Agar ◽  
First Report ◽  
Vascular Tissues ◽  
Fungal Isolates ◽  
Pathogenicity Tests ◽  
Root Cutting

A wilt disease occurred on greenhouse-grown eggplants (Solanum melongena L.) at Hanam and Yeojoo, Korea, in 1997. Lower leaves on the 2-month-old wilted eggplants exhibited gradual yellowing, interveinal necrosis, and marginal crinkling and dropped prematurely. Vascular tissues of diseased stems were discolored and turned black. Vertical sections of the stems revealed that the pith had been colonized by the fungus. The disease progressed from lower parts of the plants upward. Incidence of diseased eggplants in greenhouses was 5% on 23 May 1997. Although the incidence increased to 10% on 13 June, it remained constant through early July. Fungal isolates from discolored vascular tissues were initially whitish to cream color on potato-dextrose agar, which turned black due to the formation of microsclerotia. The fungus also produced abundant verticillate conidiophores with phialides and conidia. Based on these cultural and morphological characteristics, the fungus was identified as Verticillium dahliae Klebahn. Pathogenicity tests by root cutting, root dipping, or soil drenching resulted in similar symptoms observed in the naturally infected eggplants. Symptoms were first observed on lower leaves of each eggplant 3 weeks after inoculation. Isolation from symptomatic leaves of the inoculated eggplants yielded V. dahliae. This is the first report of occurrence of Verticillium wilt of eggplant in Korea.

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