First Report of Colletotrichum truncatum on Alfalfa in Turkey

During the summer of 1997 and 1998, a pathogen identified as Colletotrichum truncatum (Schwein.) Andrus & W.D. Moore was isolated from lesions on stems of alfalfa (Medicago sativa L.) plants in Erzurum, Turkey. Typical symptoms on stems of mature plants were large, sunken, irregularly shaped black lesions. Twenty-eight cultures of C. truncatum were isolated from stem lesions. Acervuli containing spores and dark setae were observed within lesions. Conidia were hyaline, one-celled, falcate to nearly straight with a prominent clear area in the center of highly granular cytoplasm, and measured 16.3 to 20.6 × 3.1 to 4.5 μm. These morphological characteristics were consistent with the description of C. truncatum (1). The pathogenicity of two isolates was determined on alfalfa cv. Bilensoy. Alfalfa seedlings (6-week-old) were inoculated with a conidial suspension of the fungus (1.4 × 107 conidia per ml), incubated in a moist chamber for 3 days, and subsequently transferred to growth chambers maintained at 25°C with a 12-h photoperiod. Ten plants were inoculated with each isolate. Symptoms first appeared on stems 12 days after inoculation. Sunken, irregularly shaped black lesions occasionally girdled stems of plants inoculated with C. truncatum. Symptoms did not appear on stems of control plants inoculated with sterile distilled water. C. truncatum was reisolated from symptomatic tissue. This is the first report of C. truncatum on alfalfa from Turkey. Reference: (1) B. C. Sutton. 1992. Pages 1–27 in: Colletotrichum Biology, Pathology and Control. J. A. Bailey and M. J. Jeger, eds. CAB International, Wallingford, U.K.

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First Report of Colletotrichum gloeosporioides on Russian-thistle

Plant Disease ◽

10.1094/pdis.1998.82.12.1405b ◽

1998 ◽

Vol 82 (12) ◽

pp. 1405-1405 ◽

Cited By ~ 6

Author(s):

I. Schwarczinger ◽

L. Vajna ◽

W. L. Bruckart

Keyword(s):

Colletotrichum Gloeosporioides ◽

Morphological Characteristics ◽

Ground Level ◽

Conidial Suspension ◽

First Report ◽

High Virulence ◽

Pathogenicity Tests ◽

Stem Lesions ◽

And Control ◽

The U.S

A pathogen identified as Colletotrichum gloeosporioides (Penz.) Penz. & Sacc. in Penz. was isolated from foliar and stem lesions on Russian-thistle (Salsola tragus Torner ex L.) collected in Bugac, Hungary, in 1996. Symptoms on leaves and stems began as discrete, sunken, 2- to 10-mm-diameter chlorotic spots, followed by formation of circular buff-colored lesions that eventually coalesced, desiccated, and caused plant tissue death above the lesions. Lesions that occurred near ground level usually killed the plant. Salmon-colored spore masses developed in setose acervuli in the center of the necrotic lesions. Conidia were hyaline, one-celled, falcate to nearly straight, and measured 15 to 25 × 5 to 6 μm. The teleomorph stage of the pathogen (Glomerella cingulata (Stoneman) Spauld. & H. Schrenk) was not observed in the field or on inoculated plants. These morphological characteristics of the isolate were consistent with the description of C. gloeosporioides (1). Pathogenicity was proved by completing Koch's postulates in Hungary and the U.S. Inoculation with conidial suspension (106 conidia per ml) sprayed on S. tragus plants in the greenhouse at the three- to four-leaf stage caused severe necrosis and wilting within 6 days and plant death in 2 weeks. Symptoms did not appear on control plants inoculated with sterile, distilled water. Inoculation test was repeated on 6-week-old plants and at the stage of flowering. All treated plants were killed at both stages within 4 weeks. Because of high virulence and host specificity of this isolate of C. gloeosporioides in preliminary pathogenicity tests it is being evaluated for use as a mycoherbicide for Russian-thistle control in the U.S. This is the first report of C. gloeosporioides causing anthracnose on S. tragus. Reference: (1) B. C. Sutton. Pages 1–27 in: Colletotrichum Biology, Pathology and Control. J. A. Bailei and M. J. Jeger, eds. CAB Int., Wallingford, UK, 1992.

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First Report of Ascochyta Leaf Spot Caused by Phoma exigua var. exigua on Common Bean in Greece

Plant Disease ◽

10.1094/pdis-92-4-0653c ◽

2008 ◽

Vol 92 (4) ◽

pp. 653-653 ◽

Cited By ~ 3

Author(s):

G. A. Bardas ◽

G. T. Tziros ◽

K. Tzavella-Klonari

Keyword(s):

Common Bean ◽

Leaf Spot ◽

Morphological Characteristics ◽

Pathogenic Fungi ◽

Weather Conditions ◽

Conidial Suspension ◽

Phoma Exigua ◽

First Report ◽

Plastic Bags ◽

And Control

Common bean (Phaseolus vulgaris L.) is cultivated extensively in Greece for dry and fresh bean production. During 2005 and 2006, a disease with typical blight symptoms was observed occasionally on dark red kidney, brown kidney, and black bean plants in most bean-producing areas of Greece. It rarely was destructive unless the crop had been weakened by some unfavorable environmental conditions. Infected leaves had brown-to-black lesions that developed concentric zones 10 to 30 mm in diameter and also contained small, black pycnidia. Concentric dark gray-to-black lesions also appeared on branches, stems, nodes, and pods. Infected seeds turned brown to black. Plants sometimes showed defoliation and pod drop. The fungus was consistently isolated on potato dextrose agar from diseased leaves and pods and identified as Phoma exigua var. exigua Sutton and Waterstone on the basis of morphological characteristics of conidia and pycnidia (1,2). Spores were massed in pycnidia from which they were forced in long, pink tendrils under moist weather conditions. Conidia were cylindrical to oval, allantoid, hyaline, pale yellow to brown, usually one-celled, and 2 to 3 × 5 to 10 μm. To satisfy Koch's postulates, a conidial suspension (1 × 106 conidia per ml) of the fungus was sprayed onto leaves and stems of bean seedlings (first-leaf stage) (cv. Zargana Hrisoupolis). Both inoculated and control seedlings (inoculated with sterile water) were covered with plastic bags for 72 h in a greenhouse at 23°C. Inoculated plants showed characteristic symptoms of Ascochyta leaf spot 12 to 15 days after inoculation. The fungus was reisolated from lesions that developed on the leaves and stems of all inoculated plants. The pathogen is present worldwide on bean. To our knowledge, this is the first report of P. exigua var. exigua on common bean in Greece. References: (1) D. F. Farr et al. Fungal Databases. Systematic Botany and Mycology Laboratory. Online publication. ARS, USDA, 2007. (2) B. C. Sutton and J. M. Waterstone. Ascochyta phaseolorum. No. 81 in: Descriptions of Pathogenic Fungi and Bacteria. CMI/AAB, Kew, Surrey, England, 1966.

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First report of Mochi tree (Ilex integra) Anthracnose caused by Colletotrichum fioriniae in Korea

Plant Disease ◽

10.1094/pdis-07-20-1559-pdn ◽

2020 ◽

Author(s):

Jihye Woo ◽

Jeong Eun Kim ◽

Mikyeong Kim ◽

Byeongjin Cha

Keyword(s):

South Korea ◽

Seed Quality ◽

Pathogenicity Test ◽

Conidial Suspension ◽

First Report ◽

Mature Leaves ◽

Eastern Usa ◽

Young Leaves ◽

Symptomatic Tissue ◽

And Control

Ilex integra, also called Mochi tree, is an woody ornamental common in Asia, particularly in Korea, China, Japan, and Taiwan. Anthracnose, caused by Colletotrichum spp., is an economically important disease worldwide, affecting both fruit and seed quality. In April 2019, symptoms of Anthracnose were observed on leaves from several Mochi trees in an urban planting in Wando-gun, South Korea. Irregularly shaped, light-to-dark brown spots of 1-4mm were observed on young leaves. The lesions coalesced as each spot enlarged, flat and black fruiting bodies (acervuli) occurred on the brown lesions. Four symptomatic leaves were collected; fractions were cut from symptomatic tissue, including healthy tissue, then were disinfected with 1% sodium hypochlorite and 70% ethanol, and placed on potato dextrose agar (PDA). After dark-incubation at 25℃ for 7 days two isolates were obtained, the fungal colonies appeared as white to light gray mycelium, then becoming dark and orange to pink on the underside. After acervuli were produced on the plate, orange-red conidial masses erupted. Conidia observed from two isolates were hyaline, 1-celled, and oblong with round to acute apices, and measured 7 to 12 × 2 to 5 μm (mean ± SD: 9.29 ±2.26 × 3.68± 1.31 μm) (n=30). Genomic DNA was extracted and multi-locus sequencing was performed with one representative isolate using the internal transcribed spacer (ITS) (White et al. 1990), actin (ACT) genes, chitin synthase 1 gene (CHS-1) (Carbone and Kohn 1999), glyceraldehyde-3-phosphate dehydrogenase (GAPDH), Calmodulin (CAL) (Weir et al. 2012) and submitted. Blast search results showed that the isolate had 100%, 98.45%, 99.74%, 100%, and 100% nucleotide sequence identity with those of C. fioriniae (MT607651, MH717601, MG666441, MN895544, MN974144) respectively (Jamin and Mateu 2008). The five sequences were deposited in NCBI GenBank (Accession No: MT457472, MT465884, MT465885, MT465886, MT465887), which were assigned to ITS, ACT, CHS-1, GAPDH, and CAL regions, respectively. Based on the morphology (Shivas and Tan 2009) and molecular characterization (Guerber et al. 2003), the isolate was identified as C. fioriniae. To confirm pathogenicity, a conidial suspension (10⁶ conidia/ml) of the sequenced isolate was used to inoculated, young and mature leaves of a 4-year-old Mochi tree. Ten leaves of the seedling were disinfected with 70% ethanol, then were wounded with a toothpick. The conidial suspension (20 µl) was placed on the wound. The inoculated plant and control plants were tested with sterilized water and incubated at 25℃ in a moist chamber. The pathogenicity test was repeated three times. Typical spots were observed on the young leaves 2 days after inoculation, whereas they were observed on the mature leaves 7 days after inoculation. Acervuli developed on both young and mature leaves 5 and 20 days after treatment, respectively. The control plants did not show symptoms, and the fungus was re-isolated from the inoculated plant; thus, fulfilling Koch’s Postulates. In Korea, C. fioriniae has been recorded as a pathogen of fruit (apple, eggplant and peach), but this is the first report of the fungus causing anthracnose on Mochi tree. The pathogen has been reported on leaves of a different Ilex species in the eastern USA (Farr and Rossman 2020). Although this new disease of I. integra is limited occurrence, C. fioriniae may be able to infect other plant species in South Korea.

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First Report of Cylindrocladium pseudonaviculatum Causing Leaf Spot of Pachysandra terminalis

Plant Disease ◽

10.1094/pdis-03-12-0235-pdn ◽

2012 ◽

Vol 96 (7) ◽

pp. 1069-1069 ◽

Cited By ~ 19

Author(s):

J. A. LaMondia ◽

D. W. Li ◽

R. E. Marra ◽

S. M. Douglas

Keyword(s):

Leaf Spot ◽

Morphological Characteristics ◽

Ground Cover ◽

Soil Surface ◽

Leaf Spot Disease ◽

Terminal Branch ◽

Conidial Suspension ◽

First Report ◽

Buxus Sempervirens ◽

Stem Lesions

Cylindrocladium pseudonaviculatum Crous, J.Z., Groenew. & C.F. Hill 2002 was recently reported infecting common boxwood, Buxus sempervirens L., in Connecticut (2). We isolated the pathogen from leaf and stem lesions of B. sempervirens and obtained single-spored cultures on half-strength potato dextrose agar (½PDA). The pathogen was identified as C. pseudonaviculatum by morphological characteristics (1). Colony size reached 71 mm in diameter after 14 days at room temperature on ½PDA, and was fluffy with white aerial hyphae, mars brown, and reverse color chestnut brown at the center fading to pale brown forming concentric bands. Macroconidiophores were solitary or in a group of up to three, comprised a stipe, a sterile elongation, and one to three penicillate fertile branches. The stipe was up to nine septate, 90 to 250 μm long, colorless, smooth, terminating in a naviculate or broadly ellipsoidal vesicle with a pointed or papillate apex, and 27 to 50 × 6.5 to 9 μm. Primary branches were zero- to one-septate, 20 to 36 × 4 to 5 μm; secondary branches were aseptate and 11 to 20 × 3 to 4.5 μm; tertiary branches were rare, each terminal branch producing two to five phialides; phialides were doliiform or reniform, colorless, 12 to 18 μm. Conidia were cylindrical, rounded at both ends, straight, smooth, colorless, two-celled, 48 to 55 × 4.5 to 5.5 μm, and in colorless slimy cylindrical clusters. Microconidiophores were not observed. Chlamydospores were golden to dark brown, thick-walled, and smooth or rough. Microsclerotia were present on ½PDA. Primers T1 and T22 (3) were used to amplify a portion of the β-tubulin gene from isolates Cps-CT-L1 and Cps-CT-S1. Amplified sequences were used in a BLAST search against the GenBank database to demonstrate 100% sequence identity only with other C. pseudonaviculatum strains. Both sequences were deposited in GenBank (Accession Nos. JQ866628 and JQ866629), using corresponding gene data from C. pseudonaviculatum strain STE-U 3399 (GenBank Accession No. AF449455) to distinguish coding from noncoding regions. Healthy plants of Japanese spurge, Pachysandra terminalis, with three plants per 10 cm diameter pot, were inoculated with water alone or a conidial suspension of C. pseudonaviculatum isolate Cps-CT-L1 (ATCC MYA-4891) (1.0 × 106 conidia/plant) with a handheld sprayer until runoff. Plants were kept moist in a plastic bag for 48 h at laboratory temperature and then transferred to the greenhouse. Circular lesions (1- to 4-mm diameter) were evident on leaves after 10 days. All 12 inoculated plants developed lesions, and no lesions were observed on noninoculated plants. Leaves with lesions were surface sterilized in 0.5% NaOCl for 30 s, rinsed twice in sterile water, and lesion margins plated onto water agar or ½PDA. The pathogen was reisolated from at least one leaf per plant. Koch's postulates were performed again with isolate Cps-CT-S1 (ATCC MYA-4890). After 3 weeks, many of the leaves with lesions yellowed and dropped to the soil surface and heavy sporulation of C. pseudonaviculatum and microsclerotia were observed. To our knowledge, this is the first report of C. pseudonaviculatum causing a leaf spot disease on P. terminalis. Pachysandra is a widely grown ground cover suitable for shady, humid environmental conditions that may be conducive for the development of disease. References: (1) P. Crous, et al. Sydowia 54:23, 2002. (2) K. Ivors et al. Plant Disease. 96:X, 2012. (3) K. O'Donnell and E. Cigelnik Mol. Phylogenet. Evol. 7:103, 1997.

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

Plant Disease ◽

10.1094/pdis-08-13-0821-pdn ◽

2014 ◽

Vol 98 (5) ◽

pp. 691-691 ◽

Cited By ~ 2

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.

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First Report of Damping-Off Caused by Rhizoctonia solani AG-4 on Mediterranean Fan Palm in Italy

Plant Disease ◽

10.1094/pdis-94-1-0125a ◽

2010 ◽

Vol 94 (1) ◽

pp. 125-125 ◽

Cited By ~ 3

Author(s):

G. Polizzi ◽

D. Aiello ◽

I. Castello ◽

V. Guarnaccia ◽

A. Vitale

Keyword(s):

Rhizoctonia Solani ◽

Disease Incidence ◽

Morphological Characteristics ◽

Mediterranean Area ◽

Western Mediterranean ◽

Fluorescent Light ◽

Damping Off ◽

Centraalbureau Voor ◽

First Report ◽

Stem Lesions

Mediterranean fan palm (Chamaerops humilis L.), one of just two autochthonous European palms, is native to the western Mediterranean Region in southwestern Europe and northwestern Africa. It can be found growing wild in the Mediterranean area. In Europe, this species is very popular as an ornamental plant. In March 2009, a widespread damping-off was observed in a stock of approximately 30,000 potted 1-month-old plants of C. humilis cv. Vulcano in a nursery in eastern Sicily. Disease incidence was approximately 20%. Disease symptoms consisted of lesions at the seedling shoot (plumule). Stem lesions were initially orange, turned brown, and followed by death of the entire plumule or eophyll. A fungus with mycelial and morphological characteristics of Rhizoctonia solani Kühn was consistently isolated from lesions when plated on potato dextrose agar (PDA) amended with streptomycin sulfate at 100 μg/ml. Fungal colonies were initially white, turned brown with age, and produced irregularly shaped, brown sclerotia. Mycelium was branched at right angles with a septum near the branch and a slight constriction at the branch base. Hyphal cells removed from cultures grown at 25°C on 2% water agar were determined to be multinucleate when stained with 1% safranin O and 3% KOH solution (1) and examined at ×400. Anastomosis groups were determined by pairing isolates with tester strains AG-1 IA, AG-2-2-1, AG-2-2IIIB, AG-2-2IV, AG-3, AG-4, AG-5, AG-6, and AG-11 on 2% water agar in petri plates (3). Anastomosis was observed only with tester isolates of AG-4, giving both C2 and C3 reactions (2). One representative isolate obtained from symptomatic tissues was deposited at the Fungal Biodiversity Centre, Centraalbureau voor Schimmelcultures (CBS No. 125095). Pathogenicity tests were performed on container-grown, healthy, 1-month-old seedlings. Twenty plants of C. humilis cv. Vulcano were inoculated near the base of the stem with two 1-cm2 PDA plugs from 5-day-old mycelial cultures. The same number of plants served as uninoculated controls. Plants were incubated in a growth chamber and maintained at 25°C and 95% relative humidity on a 12-h fluorescent light/dark regimen. Symptoms identical to those observed in the nursery appeared 5 days after inoculation and all plants died within 20 days. No disease was observed on control plants. A fungus identical in culture morphology to R. solani AG-4 was consistently reisolated from symptomatic tissues, confirming its pathogenicity. To our knowledge, this is the first report in the world of R. solani causing damping-off on Mediterranean fan palm. References: (1) R. J. Bandoni. Mycologia 71:873, 1979. (2) D. E. Carling. Page 37 in: Grouping in Rhizoctonia solani by Hyphal Anastomosis Reactions. Kluwer Academic Publishers, the Netherlands, 1996. (3) C. C. Tu and J. W. Kimbrough. Mycologia 65:941, 1973.

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

Plant Disease ◽

10.1094/pdis-09-21-2001-pdn ◽

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.

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First Report of Colletotrichum gloeosporioides on Chinese Rose in Argentina

Plant Disease ◽

10.1094/pdis.2000.84.12.1345b ◽

2000 ◽

Vol 84 (12) ◽

pp. 1345-1345 ◽

Cited By ~ 1

Author(s):

M. C. Rivera ◽

E. R. Wright ◽

S. Carballo

Keyword(s):

Colletotrichum Gloeosporioides ◽

Buenos Aires ◽

Morphological Characteristics ◽

Disease Prevalence ◽

Potato Dextrose Agar ◽

Conidial Suspension ◽

First Report ◽

Hibiscus Rosa Sinensis ◽

Leaf Drop ◽

Stems And Leaves

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

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

Plant Disease ◽

10.1094/pdis-02-21-0428-pdn ◽

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.

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First Report of Ramularia coleosporii causing Leaf Spot on Perilla frutescens in Korea

Plant Disease ◽

10.1094/pdis-01-21-0223-pdn ◽

2021 ◽

Author(s):

Md Aktaruzzaman ◽

Tania Afroz ◽

Hyo-Won Choi ◽

Byung Sup Kim

Keyword(s):

Leaf Spot ◽

Ipomoea Batatas ◽

Rust Fungus ◽

Morphological Characteristics ◽

Perilla Frutescens ◽

Herbaceous Plant ◽

Pathogenicity Test ◽

Conidial Suspension ◽

Single Spore ◽

First Report

Perilla (Perilla frutescens var. japonica), a member of the family Labiatae, is an annual herbaceous plant native to Asia. Its fresh leaves are directly consumed and its seeds are used for cooking oil. In July 2018, leaf spots symptoms were observed in an experimental field at Gangneung-Wonju National University, Gangneung, Gangwon province, Korea. Approximately 30% of the perilla plants growing in an area of about 0.1 ha were affected. Small, circular to oval, necrotic spots with yellow borders were scattered across upper leaves. Masses of white spores were observed on the leaf underside. Ten small pieces of tissue were removed from the lesion margins of the lesions, surface disinfected with NaOCl (1% v/v) for 30 s, and then rinsed three times with distilled water for 60 s. The tissue pieces were then placed on potato dextrose agar (PDA) and incubated at 25°C for 7 days. Five single spore isolates were obtained and cultured on PDA. The fungus was slow-growing and produced 30-50 mm diameter, whitish colonies on PDA when incubated at 25ºC for 15 days. Conidia (n= 50) ranged from 5.5 to 21.3 × 3.5 to 5.8 μm, were catenate, in simple or branched chains, ellipsoid-ovoid, fusiform, and old conidia sometimes had 1 to 3 conspicuous hila. Conidiophores (n= 10) were 21.3 to 125.8 × 1.3 to 3.6 μm in size, unbranched, straight or flexuous, and hyaline. The morphological characteristics of five isolates were similar. Morphological characteristics were consistent with those described for Ramularia coleosporii (Braun, 1998). Two representative isolates (PLS 001 & PLS003) were deposited in the Korean Agricultural Culture Collection (KACC48670 & KACC 48671). For molecular identification, a multi-locus sequence analysis was conducted. The internal transcribed spacer (ITS) regions of the rDNA, partial actin (ACT) gene and glyceraldehyde-3-phosphate dehydrogenase (GAPDH) gene were amplified using primer sets ITS1/4, ACT-512F/ACT-783R and gpd1/gpd2, respectively (Videira et al. 2016). Sequences obtained from each of the three loci for isolate PLS001 and PLS003 were deposited in GenBank with accession numbers MH974744, MW470869 (ITS); MW470867, MW470870 (ACT); and MW470868, MW470871 (GAPDH), respectively. Sequences for all three genes exhibited 100% identity with R. coleosporii, GenBank accession nos. GU214692 (ITS), KX287643 (ACT), and 288200 (GAPDH) for both isolates. A multi-locus phylogenetic tree, constructed by the neighbor-joining method with closely related reference sequences downloaded from the GenBank database and these two isolates demonstrated alignment with R. coleosporii. To confirm pathogenicity, 150 mL of a conidial suspension (2 × 105 spores per mL) was sprayed on five, 45 days old perilla plants. An additional five plants, to serve as controls, were sprayed with sterile water. All plants were placed in a humidity chamber (>90% relative humidity) at 25°C for 48 h after inoculation and then placed in a greenhouse at 22/28°C (night/day). After 15 days leaf spot symptoms, similar to the original symptoms, developed on the leaves of the inoculated plants, whereas the control plants remained symptomless. The pathogenicity test was repeated twice with similar results. A fungus was re-isolated from the leaf lesions on the inoculated plants which exhibited the same morphological characteristics as the original isolates, fulfilling Koch’s postulates. R. coleosporii has been reported as a hyperparasite on the rust fungus Coleosporium plumeriae in India & Thailand and also as a pathogen infecting leaves of Campanula rapunculoides in Armenia, Clematis gouriana in Taiwan, Ipomoea batatas in Puerto Rico, and Perilla frutescens var. acuta in China (Baiswar et al. 2015; Farr and Rossman 2021). To the best of our knowledge, this is the first report of R. coleosporii causing leaf spot on P. frutescens var. japonica in Korea. This disease poses a threat to production and management strategies to minimize leaf spot should be developed.

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