scholarly journals First Report of Stigmina palmivora Causing Leaf Spots on Phoenix roebelenii in Brazil

Plant Disease ◽  
2014 ◽  
Vol 98 (6) ◽  
pp. 849-849 ◽  
Author(s):  
A. Colmán ◽  
R. A. da Silva ◽  
R. Alves ◽  
M. Silva ◽  
R. W. Barreto
Keyword(s):  
Pure Culture ◽  
Leaf Surface ◽  
The United States ◽  
Culture Collection ◽  
Commonwealth Mycological Institute ◽  
First Report ◽  
Leaf Spots ◽  
Nucleotide Homology ◽  
Query Coverage ◽  
Representative Samples

Phoenix roebelenii (Arecaceae), known as dwarf date (tamareira-anã in Brazil), is a palm native to Southeast Asia and widely cultivated worldwide because of its ornamental value and ease of adaptation to a broad range of climates and soil types (4). In June 2012, some individuals were observed in a private garden in the municipality of Viçosa (state of Minas Gerais, Brazil) bearing numerous necrotic lesions on its leaves. Representative samples were taken, dried in a plant press, and brought to the laboratory for examination. A fungus was regularly associated with the leaf spots. Fungal structures were mounted in lactophenol and slides were examined under a microscope (Olympus BX 51). Spores were taken from sporulating colonies with a sterile fine needle and plated on PDA for isolation. A pure culture was deposited in the culture collection of the Universidade Federal de Viçosa (accession COAD1338). A dried herbarium sample was deposited in the local herbarium (VIC39741). The fungus had the following morphology: conidiophores grouped on sporodochia, cylindrical, 12 to 29 × 5 to 6 μm, dark brown; conidiogenous cells, terminal, proliferating percurrently (annellidic), 8 to 20 × 5 to 6 μm, pale to dark brown; conidia obclavate to subcylindrical, straight, 58 to 147 × 5 to 6 μm, 6 to 16 septate, hila thickened and darkened with a thin-walled projecting papilla, dark brown, and verrucose. The morphology of the Brazilian collections agrees well with the description of Stigmina palmivora (2), a species known to cause leaf spots on P. roebelenii in the United States (Florida) and Japan (3). Pathogenicity was demonstrated through inoculation of leaves of healthy plants by placing 6 mm diameter cuture disks of COAD1338 on the leaf surface followed by incubation in a moist chamber for 48 h and then transferred to a greenhouse bench at 21 ± 3°C. Typical leaf spots were observed 15 days after inoculation. DNA was extracted from the isolate growing in pure culture and ITS and LSU sequences were generated and deposited in GenBank under the accession numbers KF656785 and KF656786, respectively. These were compared by BLASTn with other entries in GenBank, and the closest match for each region were Mycosphaerella colombiensis strain X215 and M. irregulariamosa strain CPC 1362 (EU514231, GU2114441) with 93% of nucleotide homology (over 100% query coverage) for ITS and 98% of nucleotide homology (over 100% query coverage) for LSU. There are no sequences for S. palmivora deposited in public databases for comparison, but for Stigmina platani, the type species in this genus, 86% and 96% nucleotide homology for ITS and LSU with S. palmivora were found. The genus Stigmina is regarded as being polyphyletic (1) and this is probably reflected by these low homology levels found in the BLASTn search. To our knowledge, this is the first report of Stigmina palmivora in Brazil. References: (1) P. W. Crous et al. Stud. Mycol. 75:37, 2012. (2) M. B. Ellis. Dematiaceous Hyphomycetes. Commonwealth Mycological Institute, Kew, UK, 1971. (3) D. F. Farr and A. Y. Rossman. Fungal Databases. Syst. Mycol. Microbiol. Lab. ARS, USDA. Retrieved from http://nt.ars-grin.gov/fungaldatabases/ , 2013. (4) H. Lorenzi et al. Palmeira no Brasil: Exóticas e Nativas, 2nd ed. Editora Plantarum, Nova Odessa, Brazil, 2005.

scholarly journals First Report of Gray Mold (Amphobotrys ricini) on Copperleaf (Acalypha wilkesiana) in Brazil

Plant Disease ◽  
2014 ◽  
Vol 98 (2) ◽  
pp. 276-276
Author(s):  
F. M. F. Coutinho ◽  
D. M. Macedo ◽  
R. W. Barreto
Keyword(s):  
Pure Culture ◽  
Rio De Janeiro ◽  
Pacific Islands ◽  
Culture Collection ◽  
Its Sequences ◽  
Conidial Suspension ◽  
First Report ◽  
Nucleotide Homology ◽  
Query Coverage ◽  
Acalypha Wilkesiana

Acalypha wilkesiana (Euphorbiaceae), common names copperleaf or Jacob's coat (in Brazil, crista-de-peru), is a popular ornamental native from the Pacific islands. It is widely used in gardens in Brazil (4). In January 2012, a group of diseased A. wilkesiana was found in a nursery at the municipality of Itaboraí (state of Rio de Janeiro, Brazil). Later, another group of individuals of the same plant species bearing identical disease symptoms were found in a botanic garden in the city of Rio de Janeiro (Jardim Botânico do Rio de Janeiro). Diseased plants had intense leaf blight. Such leaves dropped over healthy leaves of the same or other plants and necrosis was hence initiated on such leaves. Inflorescences were also affected by blight and after becoming necrotic a dieback of supporting stems also resulted. Abundant grayish sporulation was easily observed over necrotic tissues. Samples were collected, dried in a plant press, and representative specimens were deposited in the herbarium at the Universidade Federal de Viçosa. These were from Itaboraí (VIC 31822) and from Rio de Janeiro (VIC 31931). Structures were mounted in lactophenol for observation under a microscope and isolated in pure culture on PCA plates. Isolates were deposited in the culture collection of the Universidade Federal de Viçosa with accession numbers of COAD 1112 and COAD 1108, respectively. The fungus had the following morphology: conidiophores cylindrical, up to 1,200 μm branching dicotomously at mid-length in broad angles and then branching secondarily, light brown; conidiogenous cells ampulliform, terminal, denticulate; conidia globose, 6 to 11 μm diam, subhyaline to pale brown, smooth. This combination of features is typical of Amphobotrys ricini (2), a common pathogen of castor bean (1) and several other members of the Euphorbiaceae. DNA was extracted from each isolate growing in pure culture and ITS sequences were generated and deposited in GenBank under the accession numbers JX961613 (COAD 1108) and JX961614 (COAD 1112). These were compared by BLASTn with other entries in GenBank, and the closest match for both isolates was A. ricini (JF433374) with 97% nucleotide homology (over 97% query coverage) for COAD 1112 and 98% nucleotide homology (over 98% query coverage) for COAD 1112. Pathogenicity of the isolate from A. wilkesiana was demonstrated through brush inoculation of a conidial suspension (3 × 106 conidia. mL–1) onto healthy leaves of a A. wilkesiana individual followed by its transfer to a humid chamber for 48 h. Symptoms appeared after 3 days of inoculation and sporulation appeared over necrotic tissues after 10 days. Despite the importance of A. ricini as a plant pathogen, little has been investigated on its taxonomy with molecular tools. Although morphology and host-association are the basis for the delimitation of A. ricini, our preliminary results for ITS sequences suggest that this species may include cryptic taxa that are not properly discriminated on a morphological and pathological basis. This report follows other novel reports of A. ricini on ornamental Euphorbiaceae in Brazil (3) and, to our knowledge, represents the first report of A. ricini on A. wilkesiana worldwide. References: (1) G. H. Godfrey. J. Agric. Res. 23:679, 1923. (2) G. L. Hennebert. Persoonia 7:183, 1973. (3) B. V. Lima et al. Australas. Plant Dis. Notes 3:5, 2008. (4) H. Lorenzi and H. M. Souza. Plantas Ornamentais no Brasil - Arbustivas, Herbáceas e Trepadeiras. Nova Odessa: Instituto Plantarum, 1999.

scholarly journals First Report of Volutella Blight on Pachysandra Caused by Volutella pachysandricola in China

Plant Disease ◽  
2012 ◽  
Vol 96 (4) ◽  
pp. 584-584
Author(s):  
Q. Bai ◽  
Y. Xie ◽  
R. Dong ◽  
J. Gao ◽  
Y. Li
Keyword(s):  
Morphological Characteristics ◽  
Stem Canker ◽  
Botanical Garden ◽  
The United States ◽  
Culture Collection ◽  
Leaf Blight ◽  
Conidial Suspension ◽  
First Report ◽  
Leaf Spots ◽  
Plastic Bags

Pachysandra (Pachysandra terminalis, Buxaceae) and Japanese Pachysandra, also called Japanese Spurge, is a woody ornamental groundcover plant distributed mostly in Zhejiang, Guizhou, Henan, Hubei, Sichuan, Shanxi, and Gansu provinces in China. In April 2010, P. terminalis asymptomatic plants were shipped from Beijing Botanical Garden Institute of Botany Chinese Academy of Science to the garden nursery of Jilin Agricultural University (43°48′N, 125°23′E), Jilin Province. In June 2011, Volutella blight (sometimes called leaf blight and stem canker) of P. terminalis was observed on these plants. Infected leaves showed circular or irregular, tan-to-brown spots often with concentric rings and dark margins. The spots eventually grew and coalesced until the entire leaf died. Cankers appeared as greenish brown and water-soaked diseased areas, subsequently turning brown or black, and shriveled and often girdled the stems and stolons. During wet, humid weather in autumn, reddish orange, cushion-like fruiting structures of the fungus appeared on the stem cankers and undersides of leaf spots. Symptoms of the disease were consistent with previous descriptions (2–4). Five isolates were obtained from necrotic tissue of leaf spots and cankers of stems and stolons and cultured on potato dextrose agar. The colony surface was salmon colored and slimy. Conidia were hyaline, one celled, spindle shaped, and 12.57 to 22.23 × 3.33 to 4.15 μm with rounded ends. Morphological characteristics of the fungus were consistent with the description by Dodge (2), and the fungus was identified as Volutella pachysandricola (telemorph Pseudonectria pachysandricola). The internal transcribed spacer (ITS) regions of the nuclear rDNA were amplified using primers ITS4/ITS5 (1). The ITS sequences were 553 bp long and identical among these five isolates (GenBank Accession No. HE612114). They were 100% identical to Pseudonectria pachysandricola voucher KUS-F25663 (Accession No. JN797821) and 99% identical to P. pachysandricola culture-collection DAOM (Accession No. HQ897807). Pathogenicity was confirmed by spraying leaves of clonally propagated cuttings of P. terminalis with a conidial suspension (1 × 106 conidia/ml) of the isolated V. pachysandricola. Control leaves were sprayed with sterile water. Plants were covered with plastic bags and kept in a greenhouse at 20 to 25°C for 72 h. After 5 to 8 days, typical disease symptoms appeared on leaves, while the control plants remained healthy. V. pachysandricola was reisolated from the leaf spots of inoculated plants. Pachysandra leaf blight and stem canker also called Volutella blight, is the most destructive disease of P. terminalis and previously reported in the northern humid areas of the United States (Illinois, Connecticut, Ohio, Indiana, Iowa, Massachusetts, Missouri, Kentucky, and Wisconsin), northern Europe (Britain, Germany, and Poland), and the Czech Republic. To our knowledge, this is the first report of the disease caused by V. pachysandricola in China. The disease may become a more significant problem in P. terminalis cultivation areas if the disease spreads on P. terminalis in nursery beds. References: (1) D. E. L. Cooke et al. Mycol. Res. 101:667, 1997. (2) B. O. Dodge. Mycologia 36:532, 1944. (3) S. M. Douglas. Online publication. Volutella Blight of Pachysandra. The Connecticut Agricultural Experiment Station, 2008. (4) I. Safrankova. Plant Protect. Sci.43:10, 2007.

scholarly journals First Report of Downy Mildew Caused by Peronospora lamii on Salvia splendens and Salvia coccinea

Plant Disease ◽  
2000 ◽  
Vol 84 (10) ◽  
pp. 1154-1154 ◽  
Author(s):  
G. E. Holcomb
Keyword(s):  
United States ◽  
Downy Mildew ◽  
Pathogenic Fungi ◽  
The United States ◽  
Commonwealth Mycological Institute ◽  
First Report ◽  
Leaf Spots ◽  
Salvia Splendens ◽  
Leaf Surfaces ◽  
Pathogenicity Tests

Angular chlorotic spots were observed on adaxial leaf surfaces of Salvia splendens (scarlet sage cvs. Empire Purple, Empire White, Red Pillar, and Red Hot Sally) and S. coccinea (scarlet or Texas sage cv. Lady in Red) in early May in Baton Rouge area nurseries. Leaf spots sometimes became necrotic and resulted in leaf drop. Abaxial leaf surfaces contained scattered patches of white mycelia with brown spores. Microscopic examination of mycelia revealed irregular dichotomously branched conidiophores with pointed tips and brown oval conidia. Conidiophores averaged 485 × 9 µm and conidia averaged 21 × 18 µm (16 to 26 × 15 to 23 µm) in dimensions. The fungus was identified as Peronospora lamii A. Braun (= P. swinglei Ellis & Everh.) based on these characters and its known occurrence on Salvia spp. and five other genera in the family Lamiaceae (2). Pathogenicity tests were performed by washing conidia from infected leaves into distilled water and mistinoculating S. coccinea cv. Lady in Red and S. splendens cv. Empire Purple with 50,000 spores/ml. Plants were held in a dew chamber at 20°C for 3 days, then moved to a greenhouse where temperatures ranged from 18 to 32°C. Typical angular chlorotic leaf spots developed on inoculated plants within 6 to 8 days and noninoculated plants remained healthy. The fungus did not sporulate under these greenhouse temperatures, but infected leaves that were removed and placed in a moist chamber at 25°C produced conidiophores and brown conidia typical of P. lamii within 2 to 3 days. P. lamii has been reported previously on S. officinalis (3) and S. reflexa (1) in the United States. This is the first report of downy mildew on S. coccinea and S. splendens. Appearance of the disease in retail nurseries that obtained plants from out of state (Arkansas) suggests a widespread occurrence of the disease on these host plants. References: (1) D. F. Farr et al. 1989. Fungi on Plants and Plant Products in the United States. American Phytopathological Society, St. Paul, MN. (2) S. M. Francis. 1981. Peronospora lamii. Descriptions of Pathogenic Fungi and Bacteria No. 688. Commonwealth Mycological Institute, Kew, England. (3) R. T. McMillan and W. R. Graves. Plant Dis. 78:317, 1994.

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 Septoria pistaciae Causing Leaf Spot of Pistachio in Egypt

Plant Disease ◽  
2006 ◽  
Vol 90 (12) ◽  
pp. 1553-1553 ◽  
Author(s):  
Waffa M. Haggag ◽  
M. S. M. Abou Rayya ◽  
N. E. Kasim
Keyword(s):  
Leaf Surface ◽  
Infected Plant ◽  
The United States ◽  
Pistacia Vera ◽  
Rooted Cuttings ◽  
First Report ◽  
Leaf Spots ◽  
Plastic Bags ◽  
Dark Green ◽  
Slow Growing

In May 2006, leaf spots were observed on approximately 60% of 8-year-old pistachio (Pistacia vera L.) trees in an orchard located at Rhafah, north of Sinai, Egypt. These spots were typically circular, or occasionally irregular, with white-to-light tan or gray centers and a purple or brown border measuring 1 to 5 mm in diameter, or occasionally larger on the upper leaf surface. A narrow, brown border surrounded the spot, and with age, the lesion cracked. Spots occasionally turned brown and closed to form blotches. Fungal isolates from the leaf spots were identified as Septoria pistaciae on the basis of characteristics of pycnidia and conidia. From the leaf spots, numerous black pycnidia were found that produced hyaline conidia, 3 to 7 septate, generally filiform although tapering at one end, and measuring 46 to 75 × 3 to 4 μm. Pycnidia were dark, separate, globe shaped with an ostiole from which conidia were extruded, and erupted through the surface of infected plant tissue. Conidia were produced on short conidiophores. Single conidial isolations onto 2% malt agar consistently formed slow-growing, dark green colonies. To confirm the pathogenicity of the isolate of S. pistaciae, a suspension of 5 × 105 conidia per ml in water was applied at 1 ml per leaf to 20 leaves of 10 rooted cuttings of pistachio trees in 30-cm pots. Ten controls were misted with water only. All plants were covered with plastic bags for 48 h on a greenhouse bench. Greenhouse temperatures ranged from 15 to 20°C with a 16-h photoperiod. After 6 days, all inoculated plants developed symptoms, and the fungus was reisolated from lesions. No symptoms were observed on control plants. S. pistaciae was previously reported on pistachio in Texas and Arizona (2,3). Reports included mention of its occurrence in the United States (California), Asia (Armenia Republic of Georgia, India, Israel, Kazakhstan, Kirgizstan, Syria, Turkey, Turkmenistan, and Uzbekistan), and Europe (Albania, France, Greece, Italy, and Portugal) (1). To our knowledge, this is the first report of Septoria leaf spots of pistachio in Egypt. References: (1) T. Andrianova and D. Minler. Septoria pistaciae. Page 159 in: IMI Descriptions of Fungi and Bacteria. CAB International, Wallingford, UK. 2004. (2) A. Chitzanidis. Ann. Inst. Phytopathol. Benaki 10:29, 1956. (3) D. J. Young and T. Michailides. Plant Dis. 73:775, 1989.

scholarly journals First Report of Armillaria mellea on a Fern from Italy

Plant Disease ◽  
2000 ◽  
Vol 84 (5) ◽  
pp. 592-592 ◽  
Author(s):  
S. Grasso ◽  
A. Pane ◽  
S. O. Cacciola
Keyword(s):  
Pure Culture ◽  
Late Summer ◽  
The United States ◽  
Selective Medium ◽  
Mount Etna ◽  
Washington Dc ◽  
First Report ◽  
Reference Isolate ◽  
Ornamental Foliage Plants ◽  
Electrophoretic Patterns

Several perennial species of rhizomatous herbaceous ferns are cultivated as ornamental foliage plants. During late summer 1999, in a garden at the foot of Mount Etna, eastern Sicily (Italy), we noted a fern hedge showing patches of withered or stunted plants. The fern was identified as Cyrtomium falcatum (L.f.) C. Presl. (=Polystichum falcatum (L.f.) Diels), a house holly fern or Japanese holly fern, which is an ornamental fern native to East and South Asia. Other woody plants in the immediate vicinity had died over the last few years, including apricot and cedar trees whose stumps had not been removed. A close examination of uprooted ferns revealed the presence of creamy white fan-shaped mycelial mats with an odor typical of Armillaria species that were intermixed with the felt-like tangle formed by the rhizomes and roots of the ferns. In autumn, clumps of honey mushrooms with an annulus grew around patches of the withered fern hedge and in other parts of the same garden. The spore print of the basidiocarp was light cream. Basidiospores (8 to 9 × 5 to 6.5 µm) examined under a microscope were hyaline and apiculate. The fungus was isolated in pure culture from infected rhizomes with the selective medium of Kulman and Hendrix (3). In pure culture on 2% malt agar, the fungus formed ribbon-shaped, contorted, fast-growing rhizomorphs that branched profusely. Mycelial proteins of the isolate were analyzed by both polyacrylamide slab gel and starch gel electrophoreses, as described by Bragaloni et al. (1). The electrophoretic patterns of five isozymes (esterase, glutamic oxalacetic transaminase, phospho-glucomutase, alcohol dehydrogenase, and polygalacturonase) of the isolate from fern were identical to those of the reference isolate of A. mellea (Vahl:Fr.) Kumm. from grapevine. Conversely, the patterns were clearly distinct from those of reference isolates from other species, including A. ostoyae (Romagnesi) Herink, A. bulbosa (Barla) Kile et Watling, and A. cepistipes Velenovsky. Thus, on the basis of cultural, morphological, and biochemical characteristics, the species infecting the fern was identified as A. mellea. This pathogen, very common and widespread on wooded or previously wooded sites, has an extremely wide host range, encompassing both woody and herbaceous plants (2,4). However, this is the first report of A. mellea on a fern in Italy. References: (1) M. Bragaloni and N. Anselmi. Eur. J. For. Pathol. 27:147, 1997. (2) D. F. Farr et al. 1989. Fungi on Plants and Plants Products in the United States. The American Phytopathological Society, St. Paul, MN. (3) E. G. Kulman and F. F. Hendrix. Phytopathology 52:1310, 1962. (4) C. G. Shaw and G. A. Kile. 1991 Armillaria root disease. Agric. Handb. No 691. U.S. Department of Agriculture Forest Service, Washington, DC.

scholarly journals First Report of Leaf Blight and Stem Canker of Pachysandra terminalis Caused by Pseudonectria pachysandricola in Korea

Plant Disease ◽  
2012 ◽  
Vol 96 (2) ◽  
pp. 287-287
Author(s):  
K. S. Han ◽  
J. H. Park ◽  
S. E. Cho ◽  
H. D. Shin
Keyword(s):  
United States ◽  
Its Region ◽  
Stem Canker ◽  
The United States ◽  
Culture Collection ◽  
Leaf Blight ◽  
First Report ◽  
Cornell University ◽  
Plastic Bags ◽  
Young Leaves

Pachysandra terminalis Siebold & Zucc., known as Japanese pachysandra, is a creeping evergreen perennial belonging to the family Buxaceae. In April 2011, hundreds of plants showing symptoms of leaf blight and stem canker with nearly 100% incidence were found in a private garden in Suwon, Korea. Plants with the same symptoms were found in Seoul in May and Hongcheon in August. Affected leaves contained tan-to-yellow brown blotches. Stem and stolon cankers first appeared as water soaked and developed into necrotic lesions. Sporodochia were solitary, erumpent, circular, 50 to 150 μm in diameter, salmon-colored, pink-orange when wet, and with or without setae. Setae were hyaline, acicular, 60 to 100 μm long, and had a base that was 4 to 6 μm wide. Conidiophores were in a dense fascicle, not branched, hyaline, aseptate or uniseptate, and 8 to 20 × 2 to 3.5 μm. Conidia were long, ellipsoid to cylindric, fusiform, rounded at the apex, subtruncate at the base, straight to slightly bent, guttulate, hyaline, aseptate, 11 to 26 × 2.5 to 4.0 μm. A single-conidial isolate formed cream-colored colonies that turned into salmon-colored colonies on potato dextrose agar (PDA). Morphological and cultural characteristics of the fungus were consistent with previous reports of Pseudonectria pachysandricola B.O. Dodge (1,3,4). Voucher specimens were housed at Korea University (KUS). Two isolates, KACC46110 (ex KUS-F25663) and KACC46111 (ex KUS-F25683), were accessioned in the Korean Agricultural Culture Collection. Fungal DNA was extracted with DNeasy Plant Mini DNA Extraction Kits (Qiagen Inc., Valencia, CA). The complete internal transcribed spacer (ITS) region of rDNA was amplified with the primers ITS1/ITS4 and sequenced using ABI Prism 337 automatic DNA sequencer (Applied Biosystems, Foster, CA). The resulting sequence of 487 bp was deposited in GenBank (Accession No. JN797821). This showed 100% similarity with a sequence of P. pachysandricola from the United States (HQ897807). Isolate KACC46110 was used in pathogenicity tests. Inoculum was prepared by harvesting conidia from 2-week-old cultures on PDA. Ten young leaves wounded with needles were sprayed with conidial suspensions (~1 × 106 conidia/ml). Ten young leaves that served as the control were treated with sterile distilled water. Plants were covered with plastic bags to maintain a relative humidity of 100% at 25 ± 2°C for 24 h. Typical symptoms of brown spots appeared on the inoculated leaves 4 days after inoculation and were identical to the ones observed in the field. P. pachysandricola was reisolated from 10 symptomatic leaf tissues, confirming Koch's postulates. No symptoms were observed on control plants. Previously, the disease was reported in the United States, Britain, Japan, and the Czech Republic (2,3), but not in Korea. To our knowledge, this is the first report of P. pachysandricola on Pachysandra terminalis in Korea. Since this plant is popular and widely planted in Korea, this disease could cause significant damage to nurseries and the landscape. References: (1) B. O. Dodge. Mycologia 36:532, 1944. (2) D. F. Farr and A. Y. Rossman. Fungal Databases. Systematic Mycology and Microbiology Laboratory, ARS, USDA. Retrieved from http://nt.ars-grin.gov/fungaldatabases/ , September 24, 2011. (3) I. Safrankova. Plant Prot. Sci. 43:10, 2007. (4) W. A. Sinclair and H. H. Lyon. Disease of Trees and Shrubs. 2nd ed. Cornell University Press, Ithaca, NY, 2005.

scholarly journals First Report of Alternaria Leaf Spot of Banana Caused by Alternaria alternata in the United States

Plant Disease ◽  
2013 ◽  
Vol 97 (8) ◽  
pp. 1116-1116 ◽  
Author(s):  
V. Parkunan ◽  
S. Li ◽  
E. G. Fonsah ◽  
P. Ji
Keyword(s):  
United States ◽  
Alternaria Alternata ◽  
Leaf Spot ◽  
Morphological Characteristics ◽  
The United States ◽  
Its Sequencing ◽  
Single Spore ◽  
First Report ◽  
Alternaria Leaf Spot ◽  
Leaf Spots

Research efforts were initiated in 2003 to identify and introduce banana (Musa spp.) cultivars suitable for production in Georgia (1). Selected cultivars have been evaluated since 2009 in Tifton Banana Garden, Tifton, GA, comprising of cold hardy, short cycle, and ornamental types. In spring and summer of 2012, 7 out of 13 cultivars (African Red, Blue Torres Island, Cacambou, Chinese Cavendish, Novaria, Raja Puri, and Veinte Cohol) showed tiny, oval (0.5 to 1.0 mm long and 0.3 to 0.9 mm wide), light to dark brown spots on the adaxial surface of the leaves. Spots were more concentrated along the midrib than the rest of the leaf and occurred on all except the newly emerged leaves. Leaf spots did not expand much in size, but the numbers approximately doubled during the season. Disease incidences on the seven cultivars ranged from 10 to 63% (10% on Blue Torres Island and 63% on Novaria), with an average of 35% when a total of 52 plants were evaluated. Six cultivars including Belle, Ice Cream, Dwarf Namwah, Kandarian, Praying Hands, and Saba did not show any spots. Tissue from infected leaves of the seven cultivars were surface sterilized with 0.5% NaOCl, plated onto potato dextrose agar (PDA) media and incubated at 25°C in the dark for 5 days. The plates were then incubated at room temperature (23 ± 2°C) under a 12-hour photoperiod for 3 days. Grayish black colonies developed from all the samples, which were further identified as Alternaria spp. based on the dark, brown, obclavate to obpyriform catenulate conidia with longitudinal and transverse septa tapering to a prominent beak attached in chains on a simple and short conidiophore (2). Conidia were 23 to 73 μm long and 15 to 35 μm wide, with a beak length of 5 to 10 μm, and had 3 to 6 transverse and 0 to 5 longitudinal septa. Single spore cultures of four isolates from four different cultivars were obtained and genomic DNA was extracted and the internal transcribed spacer (ITS1-5.8S-ITS2) regions of rDNA (562 bp) were amplified and sequenced with primers ITS1 and ITS4. MegaBLAST analysis of the four sequences showed that they were 100% identical to two Alternaria alternata isolates (GQ916545 and GQ169766). ITS sequence of a representative isolate VCT1FT1 from cv. Veinte Cohol was submitted to GenBank (JX985742). Pathogenicity assay was conducted using 1-month-old banana plants (cv. Veinte Cohol) grown in pots under greenhouse conditions (25 to 27°C). Three plants were spray inoculated with the isolate VCT1FT1 (100 ml suspension per plant containing 105 spores per ml) and incubated under 100% humidity for 2 days and then kept in the greenhouse. Three plants sprayed with water were used as a control. Leaf spots identical to those observed in the field were developed in a week on the inoculated plants but not on the non-inoculated control. The fungus was reisolated from the inoculated plants and the identity was confirmed by morphological characteristics and ITS sequencing. To our knowledge, this is the first report of Alternaria leaf spot caused by A. alternata on banana in the United States. Occurrence of the disease on some banana cultivars in Georgia provides useful information to potential producers, and the cultivars that were observed to be resistant to the disease may be more suitable for production. References: (1) E. G. Fonsah et al. J. Food Distrib. Res. 37:2, 2006. (2) E. G. Simmons. Alternaria: An identification manual. CBS Fungal Biodiversity Center, Utrecht, Netherlands, 2007.

scholarly journals First Report of Leaf Spot of Sweet Basil Caused by Cercospora guatemalensis in Korea

Plant Disease ◽  
2012 ◽  
Vol 96 (10) ◽  
pp. 1580-1580
Author(s):  
J. H. Park ◽  
K. S. Han ◽  
J. Y. Kim ◽  
H. D. Shin
Keyword(s):  
Leaf Spot ◽  
Morphological Characteristics ◽  
Its Region ◽  
Culture Collection ◽  
Distilled Water ◽  
First Report ◽  
Sweet Basil ◽  
Organic Farm ◽  
Leaf Spots ◽  
Close Phylogenetic Relationship

Sweet basil, Ocimum basilicum L., is a fragrant herb belonging to the family Lamiaceae. Originated in India 5,000 years ago, sweet basil plays a significant role in diverse cuisines across the world, especially in Asian and Italian cooking. In October 2008, hundreds of plants showing symptoms of leaf spot with nearly 100% incidence were found in polyethylene tunnels at an organic farm in Icheon, Korea. Leaf spots were circular to subcircular, water-soaked, dark brown with grayish center, and reached 10 mm or more in diameter. Diseased leaves defoliated prematurely. The damage purportedly due to this disease has reappeared every year with confirmation of the causal agent made again in 2011. A cercosporoid fungus was consistently associated with disease symptoms. Stromata were brown, consisting of brown cells, and 10 to 40 μm in width. Conidiophores were fasciculate (n = 2 to 10), olivaceous brown, paler upwards, straight to mildly curved, not geniculate in shorter ones or one to two times geniculate in longer ones, 40 to 200 μm long, occasionally reaching up to 350 μm long, 3.5 to 6 μm wide, and two- to six-septate. Conidia were hyaline, acicular to cylindric, straight in shorter ones, flexuous to curved in longer ones, truncate to obconically truncate at the base, three- to 16-septate, and 50 to 300 × 3.5 to 4.5 μm. Morphological characteristics of the fungus were consistent with the previous reports of Cercospora guatemalensis A.S. Mull. & Chupp (1,3). Voucher specimens were housed at Korea University herbarium (KUS). An isolate from KUS-F23757 was deposited in the Korean Agricultural Culture Collection (Accession No. KACC43980). Fungal DNA was extracted with DNeasy Plant Mini DNA Extraction Kits (Qiagen Inc., Valencia, CA). The complete internal transcribed spacer (ITS) region of rDNA was amplified with the primers ITS1/ITS4 and sequenced. The resulting sequence of 548 bp was deposited in GenBank (Accession No. JQ995781). This showed >99% similarity with sequences of many Cercospora species, indicating their close phylogenetic relationship. Isolate of KACC43980 was used in the pathogenicity tests. Hyphal suspensions were prepared by grinding 3-week-old colonies grown on PDA with distilled water using a mortar and pestle. Five plants were inoculated with hyphal suspensions and five plants were sprayed with sterile distilled water. The plants were covered with plastic bags to maintain a relative humidity of 100% for 24 h and then transferred to a 25 ± 2°C greenhouse with a 12-h photoperiod. Typical symptoms of necrotic spots appeared on the inoculated leaves 6 days after inoculation, and were identical to the ones observed in the field. C. guatemalensis was reisolated from symptomatic leaf tissues, confirming Koch's postulates. No symptoms were observed on control plants. Previously, the disease was reported in Malawi, India, China, and Japan (2,3), but not in Korea. To our knowledge, this is the first report of C. guatemalensis on sweet basil in Korea. Since farming of sweet basil has recently started on a commercial scale in Korea, the disease poses a serious threat to safe production of this herb, especially in organic farming. References: (1) C. Chupp. A Monograph of the Fungus Genus Cercospora. Ithaca, NY, 1953. (2) D. F. Farr and A. Y. Rossman. Fungal Databases. Systematic Mycology & Microbiology Laboratory, ARS, USDA. Retrieved from http://nt.ars-grin.gov/fungaldatabases/ , May 5, 2012. (3) J. Nishikawa et al. J. Gen. Plant Pathol. 68:46, 2002.

scholarly journals First Report of a Leaf Spot Caused by Alternaria brassicae on the Invasive Weed Lepidium draba in North America

Plant Disease ◽  
2009 ◽  
Vol 93 (8) ◽  
pp. 846-846 ◽  
Author(s):  
A. J. Caesar ◽  
R. T. Lartey
Keyword(s):  
North America ◽  
Chinese Cabbage ◽  
Leaf Spot ◽  
The United States ◽  
Alternaria Brassicae ◽  
Voucher Specimen ◽  
First Report ◽  
Leaf Spots ◽  
Black Spots ◽  
Lepidium Draba

The exotic, rangeland weed Lepidium draba L., a brassicaceous perennial, is widely distributed in the United States. For example, Oregon contains 100,000 ha of land infested with L. draba (2). Because it is capable of aggressive spread and has the potential to reduce the value of wheat-growing land (4), it is the target of biological control research. The application of multiple pathogens has been advocated for control of other brassicaceous weeds, including the simultaneous application of biotrophic and necrotrophic pathogens (3). In pursuit of this approach, in 2007, we discovered the occurrence of leaf spots on approximately 90% of L. draba plants near Shepherd, MT, which were distinct from leaf lesions caused by Cercospora bizzozeriana (1). The lesions were initially tiny, black spots enlarging over time to become circular to irregular and cream-colored around the initial black spots and sometimes with dark brown borders or chlorotic halos. Conidia from the lesions were light brown, elongate and obclavate, produced singly from short conidia, with 8 to 12 transverse septa, and 2 to 6 longitudinal septa. The spore body measured 25 to 35 × 200 to 250 μm with a beak cell 42 to 100 μm long. On the basis of conidial and cultural characteristics, the fungus was identified as Alternaria brassicae (Berk.) Sacc. Leaf tissues bordering lesions were plated on acidified potato dextrose agar. Colonies on V8 and alfalfa seed agar were black with concentric rings, eventually appearing uniformly black after 10 to 14 days. The internal transcribed spacer region of rDNA was amplified using primers ITS1 and ITS4 and sequenced. BLAST analysis of the 575-bp fragment showed a 100% homology with a sequence of A. brassicae Strain B from mustard (GenBank Accession No. DQ156344). The nucleotide sequence has been assigned GenBank Accession No. FJ869872. For pathogenicity tests, aqueous spore suspensions approximately 105/ml were prepared from cultures grown at 20 to 25°C for 10 to 14 days on V8 agar and sprayed on leaves of three L. draba plants. Inoculated plants were enclosed in plastic bags and incubated at 20 to 22°C for 72 to 80 h. In addition, three plants of the following reported hosts of A. brassicae were inoculated: broccoli, canola, Chinese cabbage, collards, broccoli raab, kale, mustard greens, radish, rape kale, and turnip. Within 10 days, leaf spots similar to those described above developed on plants of radish, canola, Chinese cabbage, and turnip and A. brassicae was reisolated and identified. Control plants sprayed with distilled water remained symptomless. These inoculations were repeated and results were the same. To our knowledge, this is the first report of a leaf spot disease caused by A. brassicae on L. draba in North America. A voucher specimen has been deposited with the U.S. National Fungus Collections (BPI No. 878750A). References: (1) A. J. Caesar et al. Plant Dis. 93:108, 2009. (2) G. L. Kiemnec and M. L. McInnis. Weed Technol. 16:231, 2002. (3) A. Maxwell and J. K. Scott. Adv. Bot. Res. 43:143, 2005. (4) G. A. Mulligan and J. N. Findlay. Can. J. Plant Sci. 54:149, 1974.

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