scholarly journals First Report of Leaf Spot Caused by Cercospora bizzozeriana on Hoary Cress in Russia

Plant Disease ◽  
2008 ◽  
Vol 92 (2) ◽  
pp. 316-316
Author(s):  
Z. M. Mukhina ◽  
D. Kassanelly ◽  
D. K. Berner ◽  
H. J. Dubin
Keyword(s):  
Biological Control Agent ◽  
Aqueous Suspension ◽  
Science Research ◽  
Research Unit ◽  
Invasive Weed ◽  
Voucher Specimen ◽  
First Report ◽  
Leaf Spots ◽  
White Leaf ◽  
Hoary Cress

Hoary cress (Lepidium draba (L.) subsp. draba (synonym = Cardaria draba (L.) Desv.) (1), family Brassicaceae, is a common weed in Russia but it is an aggressive invasive weed in the northwestern United States. In the summer of 2006, dying hoary cress plants were found near Kugoyeyskoye in the Krylovskoy area of the Krasnodar Region of Russia. Plants had grayish white leaf spots on most of the leaves. In some cases, the diseased leaf spots dropped out of the leaves producing shot-holes. In most cases, the leaf spots coalesced and the leaves wilted and died. Diseased leaves were collected, air dried, and sent to the quarantine facility of the Foreign Disease-Weed Science Research Unit (FDWSRU), USDA/ARS, Fort Detrick, MD. The air-dried leaves were observed microscopically, and numerous conidiophores and conidia were observed on both sides of leaves within and around the lesions. The fungus isolated (DB06-018) conformed to the description of Cercospora bizzozeriana Saccardo & Berlese (2). Conidiophores were 1 to 5 geniculate, unbranched, pale olive-brown, and uniform in color and width (4 μm). Conidia were multiseptate, hyaline, cylindric, straight to slightly curved, and measured 57 to 171 μm (average 103) long × 3.8 to 6.7 μm (average 4.6) wide. Leaves of rosettes (10 to 15 cm in diameter) of four hoary cress plants were spray inoculated with an aqueous suspension of conidia (1 × 105/ml) and mycelia harvested from 6- to 8-day-old cultures grown on V8 medium. Inoculated plants and two noninoculated plants were placed in a dew chamber at 20°C in darkness and continuous dew. After 96 h, plants were moved from the dew chamber to a greenhouse bench. All plants were watered twice daily. After 12 days, symptoms were observed on all inoculated plants. Symptoms were identical to those observed in the field in Russia. No symptoms were observed on noninoculated plants. C. bizzozeriana was reisolated from the leaves of all symptomatic plants. Nucleotide sequences were obtained for the internal transcribed spacer regions ITS1 and ITS2 and the 5.8S ribosomal RNA gene (GenBank Accession No. EU031780) and aligned with the same sequences obtained from another C. bizzozeriana isolate (GenBank Accession No. DQ370428) collected in Tunisia. There was 100% alignment of the two sequences with no gaps. Both isolates of C. bizzozeriana are destructive pathogens on hoary cress and locally severe epidemics have been observed in both Russia and Tunisia (4). This fungus has also been reported in North America (3) and has the potential as a biological control agent where the weed is a problem. To our knowledge, this is the first report of C. bizzozeriana on L. draba subsp. draba in Russia. A voucher specimen has been deposited with the U.S. National Fungus Collections (BPI 878175). Live cultures are being maintained at FDWSRU. References: (1) I. A. Al-Shehbaz and K. Mummenhoff. Novon 12:5, 2002. (2) C. Chupp. A Monograph of the Fungus Genus Cercospora. C. Chupp, Ithaca, New York, 1953. (3) I. L. Conners. Res. Bra. Can. Dep. Agric. 1251:1, 1967. (4) T. Souissi et al. Plant Dis. 89:206, 2005.

scholarly journals First Report of a Leaf Spot Caused by Cercospora bizzozeriana on Lepidium draba subsp. draba in Tunisia

Plant Disease ◽  
2005 ◽  
Vol 89 (2) ◽  
pp. 206-206
Author(s):  
T. Souissi ◽  
D. K. Berner ◽  
H. J. Dubin
Keyword(s):  
United States ◽  
Biological Control ◽  
Biological Control Agent ◽  
Aqueous Suspension ◽  
The United States ◽  
Voucher Specimen ◽  
First Report ◽  
Leaf Spots ◽  
White Leaf ◽  
Lepidium Draba

Lepidium draba (L.) subsp. draba (synonym = Cardaria draba (L.) Desv.), commonly known as white-top or hoary-cress (1), family Brassicaceae, is a common weed and emerging problem in wheat in Tunisia. It is also a problematic invasive weed in the northwestern United States and a target of biological control efforts. During the summer of 2002, dying L. draba plants were found around Tunis, Tunisia. Plants had grayish white leaf spots on most of the leaves. In some cases, the leaf spots dropped out of the leaves producing “shot-holes”. In most cases, the leaf spots coalesced, and the leaves wilted and died. Diseased leaves were collected, air-dried, and sent to the quarantine facility of the Foreign Disease-Weed Science Research Unit (FDWSRU), USDA/ARS, Fort Detrick, MD. The air-dried leaves were observed microscopically, and numerous conidiophores and conidia were observed on both sides of the leaves within and around the lesions. The fungus isolated (DB03-009) conformed to the description of Cercospora bizzozeriana Saccardo & Berlese (2). Conidiophores were unbranched, pale olive-brown, 1 to 5 geniculate, and uniform in color and width. Conidia were hyaline, straight to slightly curved, multiseptate, and 57 to 171 × 3.8 to 6.7 µm (average 103 to 4.6 µm). Stems and leaves of 12 rosettes (10 to 15 cm in diameter) of 6-week-old L. draba plants were spray inoculated with an aqueous suspension of conidia (1 × 105/ml) harvested from 6- to 8-day-old cultures grown on carrot leaf decoction agar. Six of the plants and two noninoculated plants were placed in a dew chamber at 22°C in darkness and continuous dew. The other half of the plants and two noninoculated plants were placed on a greenhouse bench at approximately 25°C and covered with clear polyethylene bags. After 72 h, plants from the dew chamber were moved to a greenhouse bench, and the bagged plants were uncovered. All plants were watered twice daily. After 9 days, symptoms were observed on the plants that had been bagged but not on the plants from the dew chamber. Symptoms were identical to those observed in the field in Tunisia and included “shot holes”. No symptoms were observed on noninoculated plants. C. bizzozeriana was reisolated from the leaves of all symptomatic plants. Completion of Koch's postulates was repeated with an additional five plants. This isolate of C. bizzozeriana is a destructive pathogen on L. draba subsp. draba, and severe disease can be produced by inoculation of foliage with an aqueous suspension of conidia. This isolate is a good candidate for mycoherbicide development in Tunisia where the weed and pathogen are indigenous. However, some commercially grown Brassica species were found susceptible to this isolate, which will preclude its use as a classical biological control agent in the United States. To our knowledge, this is the first report of C. bizzozeriana on L. draba subsp. draba in Tunisia. A voucher specimen has been deposited at the U.S. National Fungus Collections (BPI 843753). Live cultures are being maintained at FDWSRU and the Institut National Agronomique de Tunisie, Tunis, Tunisia. References: (1) I. A. Al-Shehbaz and K. Mummenhoff. Novon 12:5, 2002. (2) C. Chupp. A Monograph of the Fungus Genus Cercospora. C. Chupp, Ithaca, New York, 1953.

scholarly journals First Report of Stem Canker of Salsola tragus Caused by Diaporthe eres in Russia

Plant Disease ◽  
2009 ◽  
Vol 93 (1) ◽  
pp. 110-110 ◽  
Author(s):  
T. Kolomiets ◽  
Z. Mukhina ◽  
T. Matveeva ◽  
D. Bogomaz ◽  
D. K. Berner ◽  
...  
Keyword(s):  
United States ◽  
Biological Control ◽  
Biological Control Agent ◽  
Aqueous Suspension ◽  
Stem Canker ◽  
The United States ◽  
Invasive Weed ◽  
Voucher Specimen ◽  
First Report ◽  
Stem Lesions

Salsola tragus L. (Russian thistle) is a problematic invasive weed in the western United States and a target of biological control efforts. In September of 2007, dying S. tragus plants were found along the Azov Sea at Chushka, Russia. Dying plants had irregular, necrotic, canker-like lesions near the base of the stems and most stems showed girdling and cracking. Stem lesions were dark brown and contained brown pycnidia within and extending along lesion-free sections of the stems and basal portions of leaves. Diseased stems were cut into 3- to 5-mm pieces and disinfested in 70% ethyl alcohol. After drying, stem pieces were placed into petri dishes on the surface of potato glucose agar. Numerous, dark, immersed erumpent pycnidia with a single ostiole were observed in all lesions after 2 to 3 days. Axenic cultures were sent to the Foreign Disease-Weed Science Research Unit, USDA, ARS, Ft. Detrick, MD for testing in quarantine. Conidiophores were simple, cylindrical, and 5 to 25 × 2 μm (mean 12 × 2 μm). Alpha conidia were biguttulate, one-celled, hyaline, nonseptate, ovoid, and 6.3 to 11.5 × 1.3 to 2.9 μm (mean 8.8 × 2.0 μm). Beta conidia were one-celled, filiform, hamate, hyaline, and 11.1 to 24.9 × 0.3 to 2.5 μm (mean 17.7 × 1.2 μm). The isolate was morphologically identified as a species of Phomopsis, the conidial state of Diaporthe (1). The teleomorph was not observed. A comparison with available sequences in GenBank using BLAST found 528 of 529 identities with the internal transcribed spacer (ITS) sequence of an authentic and vouchered Diaporthe eres Nitschke (GenBank DQ491514; BPI 748435; CBS 109767). Morphology is consistent with that of Phomopsis oblonga (Desm.) Traverso, the anamorph of D. eres (2). Healthy stems and leaves of 10 30-day-old plants of S. tragus were spray inoculated with an aqueous suspension of conidia (1.0 × 106 alpha conidia/ml plus 0.1% v/v polysorbate 20) harvested from 14-day-old cultures grown on 20% V8 juice agar. Another 10 control plants were sprayed with water and surfactant without conidia. Plants were placed in an environmental chamber at 100% humidity (rh) for 16 h with no lighting at 25°C. After approximately 24 h, plants were transferred to a greenhouse at 20 to 25°C, 30 to 50% rh, and natural light. Stem lesions developed on three inoculated plants after 14 days and another three plants after 21 days. After 70 days, all inoculated plants were diseased, four were dead, and three had more than 75% diseased tissue. No symptoms occurred on control plants. The Phomopsis state was recovered from all diseased plants. This isolate of D. eres is a potential biological control agent of S. tragus in the United States. A voucher specimen has been deposited with the U.S. National Fungus Collections (BPI 878717). Nucleotide sequences for the ribosomal ITS regions (ITS 1 and 2) were deposited in GenBank (Accession No. EU805539). To our knowledge, this is the first report of stem canker on S. tragus caused by D. eres. References: (1) B. C. Sutton. Page 569 in: The Coelomycetes. CMI, Kew, Surrey, UK, 1980. (2) L. E. Wehmeyer. The Genus Diaporthe Nitschke and its Segregates. University of Michigan Press, Ann Arbor, 1933.

scholarly journals First Report of Leaf Spot Caused by a Cercosporella sp. on Centaurea solstitialis in Greece

Plant Disease ◽  
2004 ◽  
Vol 88 (12) ◽  
pp. 1382-1382 ◽  
Author(s):  
F. M. Eskandari ◽  
D. K. Berner ◽  
J. Kashefi ◽  
L. Strieth
Keyword(s):  
United States ◽  
Biological Control ◽  
Biological Control Agent ◽  
Aqueous Suspension ◽  
The United States ◽  
Centaurea Solstitialis ◽  
Voucher Specimen ◽  
Disease Symptoms ◽  
First Report ◽  
Leaf Spots

Centaurea solstitialis L. (yellow starthistle [YST]), family Asteraceae, an invasive weed in California and the western United States is targeted for biological control. During the spring of 2004, an epidemic of dying YST plants was found near Kozani, Greece (40°22′07″N, 21°52′35″E, 634 m elevation). Rosettes of YST had small, brown leaf spots on most of the lower leaves. In many cases, these spots coalesced and resulted in necrosis of many of the leaves and death of the rosette. Along the roadside where the disease was found, >100 of the YST plants showed disease symptoms. Diseased plants were collected, air dried, and sent to the quarantine facility of the Foreign Disease-Weed Science Research Unit (FDWSRU), USDA, ARS, Fort Detrick, MD. Diseased leaves were surface disinfested and placed on moist filter paper in petri dishes. Conidiophores and conidia were observed after 48 h. The fungal isolate, DB04-011, was isolated from these diseased leaves. Pathogenicity tests were performed by spray inoculating the foliage of 20 4-week-old YST rosettes with an aqueous suspension of 1 × 106 conidia per ml. Conidia were harvested from 2-week-old cultures grown on modified potato carrot agar (MPCA). Inoculated plants were placed in an environmental chamber at 23°C with 8 h of daily light and continuous dew for 48 h. Inoculated and control plants were moved to a 20°C greenhouse bench and watered twice per day. After 7 days, leaf spots were observed first on lower leaves. After 10–12 days, all inoculated plants showed typical symptoms of the disease. No symptoms developed on control plants. The pathogen, DB04-011, was consistently isolated from symptomatic leaves of all inoculated plants. Disease symptoms were scattered, amphigenous leaf spots in circular to subcircular spots that were 0.2 to 7 mm in diameter and brownish with distinct dark green margins. Intraepidermal stromata, 14 to 77 μm in diameter and pale yellow to brown, were formed within the spots. Conidiophores that arose from the stromata were straight, subcylindrical, simple, 70 to 95 × 2.8 to 4 μm, hyaline, smooth, and continuous or septate with conidial scars that were somewhat thickened, colorless, and refractive. Primary conidia were subcylindrical, slightly obclavate or fusiform, ovoid, 21 to 49 × 5 to 7.5 μm, 0 to 5 septate, hyaline, smooth, had a relatively rounded apex, and the hilum was slightly thickened. Conidial dimensions on MPCA were 11.2 to 39.2 × 4.2 to 7 μm (average 25.5 × 5.5 μm). Koch's postulates were repeated two more times with 20 and 16 plants. On the basis of fungal morphology, the organism was identified as a Cercosporella sp., (1,2; U. Braun and N. Ale-Agha, personal communication). To our knowledge, this is the first report of this genus of fungus parasitizing YST. Results of host range tests will establish if this isolate of Cercosporella has potential as a biological control agent of YST in the United States. A voucher specimen has been deposited with the U.S. National Fungus Collections (BPI 844247). Live cultures are being maintained at FDWSRU and European Biological Control Laboratoryt (EBCL), Greece. References: (1) U. Braun. A Monograph of Cercosporella, Ramularia and Allied Genera (Phytopathogenic Hyphomycetes) Vol. 1. IHW-Verlage, Eching-by-Munich, 1995. (2) U. Braun. A Monograph of Cercosporella, Ramularia and Allied Genera (Phytopathogenic Hyphomycetes) Vol. 2. IHW-Verlage, 1998.

scholarly journals First Report of an Ovary Smut of Italian Thistle Caused by a Microbotryum sp. in Greece

Plant Disease ◽  
2006 ◽  
Vol 90 (5) ◽  
pp. 681-681 ◽  
Author(s):  
D. K. Berner ◽  
M. B. McMahon ◽  
J. Kashefi ◽  
E. Erbe
Keyword(s):  
United States ◽  
Biological Control ◽  
Biological Control Agent ◽  
Science Research ◽  
The United States ◽  
Internal Transcribed Spacers ◽  
Smut Fungi ◽  
Invasive Weed ◽  
Voucher Specimen ◽  
First Report

Italian thistle (Carduus pycnocephalus L.), family Asteraceae, is a common weed in Greece. It is also a problematic invasive weed in the western United States and a target of biological control efforts. In May 2005, smutted capitula of Italian thistle were found in an abandoned field in Halkiades, Greece. A total of 38 smutted plants, representing approximately 20% of those plants present, were found in a portion of the field that was lightly infested with Italian thistle. In most cases, capitula of all diseased flowers were smutted. In one or two cases, capitula on some branches of the plants were smutted, whereas capitula on other branches were healthy. Diseased capitula were noticeably more globose than healthy ovoid capitula, and diseased capitula did not open completely. When diseased capitula were split open, the ovaries in all florets within the capitula were filled with powdery masses of smut teliospores. Diseased capitula were collected, air dried, and sent to the quarantine facility of the Foreign Disease-Weed Science Research Unit (FDWSRU), USDA/ARS, Fort Detrick, MD. Teliospores within the capitula were extracted and observed microscopically. Teliospores of isolate DB05-014 were relatively uniform in shape and size, globose, 12.0 to 17.3 × 12.3 to 18.0 μm (mean 14.5 × 15.1 μm), violet tinted pale to medium yellowish-brown; wall reticulate appearing as coarse, radiate wings on the spore margin, 5 to 7 polyangular meshes per spore diameter, muri, 0.7 to 2.0 μm high in optical median view appearing as gradually narrowing blunt spines, 0.5 to 1 μm wide at their basis; in scanning electron microscopy (SEM), the meshes were subpolygonal, wall and interspaces were finely verruculose. Teliospores were more globose and slightly smaller than the description of Microbotryum cardui (A. A. Fischer Waldh.) Vánky (2), but the mean sizes were within the described range. When compared with teliospores of M. cardui on C. acanthoides, the numbers of polyangular meshes per spore diameter were within the range of the description using SEM, but the muri were about one-half of the height of those described. Nucleotide sequences for the internal transcribed spacers (ITS 1 and 2) and 5.8S ribosomal region (GenBank Accession No. AY280460) were aligned with sequences of other smut fungi using the BLAST algorithm of the National Center for Biotechnology Information. The closest alignment of DB05-014 was with M. scorzonerae (590 of 627 bp identities or 94% with 2% gaps). No sequences of M. cardui were available for comparison, but only M. cardui has been reported on Carduus spp. (1,2). Another smut reported on a Carduus sp. is Thecaphora trailii (1). DB05-014 is a likely variant of M. cardui from a previously unknown host. Italian thistle is an annual plant that reproduces solely by seeds (achenes). Because of the lack of seed production on smutted plants and the systemic nature of the disease, this fungus has great potential as a biological control agent for Italian thistle in the United States. A voucher specimen has been deposited with the U.S. National Fungus Collections (BPI 871812). To our knowledge this is the first report of a Microbotryum sp. parasitizing C. pycnocephalus. References: (1) K. Vánky. European Smut Fungi. Gustav Fischer Verlag, Stuttgart, Germany, 1994. (2) K. Vánky and D. Berner. Mycotaxon 85:307, 2003.

scholarly journals First Report of Leaf Spot Caused by Periconia igniaria on Yellow Starthistle in Russia

Plant Disease ◽  
2008 ◽  
Vol 92 (6) ◽  
pp. 983-983 ◽  
Author(s):  
T. Kolomiets ◽  
L. Pankratova ◽  
Z. Mukhina ◽  
D. Kassanelly ◽  
T. Matveeva ◽  
...  
Keyword(s):  
Aqueous Suspension ◽  
Soil Fungus ◽  
Aerial Mycelium ◽  
Its Sequences ◽  
Yellow Starthistle ◽  
Invasive Weed ◽  
Voucher Specimen ◽  
First Report ◽  
Russian State ◽  
Nutrition Medium

Yellow starthistle (YST), Centaurea solstitialis L., is a weedy plant that is widely distributed in the Krasnodar Region of Russia. It is also an aggressive invasive weed in the western United States and a target of biological control efforts. In the summer of 2006, several hundred diseased plants were found near Taman, Russia. Symptoms of the disease were yellow, water-soaked leaf spots. Diseased leaves were collected, air dried, and sent to the Russian State Collection of Phytopathogenic Organisms at the All Russia Institute of Phytopathology (ARIP). The fungus isolated from the diseased leaves conformed to Periconia igniaria E.W. Mason & M.B. Ellis (teleomorph Didymosphaeria igniaria C. Booth) (1). Colonies of the fungus grew rapidly on potato glucose nutrition medium with aerial mycelium from fluffy to pressed and colorless at the beginning and darkening to black with age. The medium side of the colonies gradually became violet purple to wine colored. Conidiophores had aerial mycelia as much as 550 μm long and 9 to 13 μm wide tapering to 6 to 10 μm. Conidiophores were dark with short, swollen branched stipes. Conidia, formed in short twisted chains, were spherical, dark brown, 7 to 9 μm in diameter, and covered by 1 μm long spines. Yellow starthistle plants were grown in growth chambers with day/night air temperatures of 26 to 28/20 to 22°C, 60 to 70% relative air humidity, and 10,000 lx light for 16 h. Fifteen plants in the rosette stage were spray inoculated with an aqueous suspension of P. igniaria conidia at 5 × 106 conidia/ml and 5 ml per plant. Disease on leaves was observed on all plants 3 to 4 weeks after inoculation when the plants started to bolt. When the plants reached flowering stage, diffused yellow spots were observed on stems and inflorescences and all flowers died. Diseased leaves were surface disinfested and put on potato saccharose nutrition medium. P. igniaria was reisolated from 3 to 5 leaves of each plant and from flowers and stems that developed from 10 inoculated rosettes. Flowers of 10 YST plants were also inoculated with P. igniaria isolated from the previously inoculated plants. Disease developed in the flowers of all inoculated plants, and the symptoms were identical to those observed when rosettes were inoculated and disease followed bolting and flowering. No symptoms developed on four noninoculated plants included in each test. Internal transcribed spacer (ITS) sequences of the fungus were obtained and compared with sequences from GenBank. An uncultured soil fungus and three isolates of P. macrospinosa Lefebvre & Aar.G. Johnson produced the best homology (96%). No sequences for P. igniaria were available for comparison, but the description of P. macrospinosa (conidia 18 to 32 μm in diameter with 2.5 to 6 μm long spines) is clearly different than our isolate. ITS sequences for our isolate have been deposited in GenBank (Accession No. EU367468) and a voucher specimen has been deposited with the U.S. National Fungus Collection (BPI 878355). To our knowledge, this is the first report of P. igniaria causing disease on YST. Live cultures are being maintained at the Russian State Collection of Phytopathogenic Organisms in ARIP. Reference: (1) M. B. Ellis. Dematiaceous Hyphomycetes. CMI, Kew, UK, 1971.

scholarly journals Leaf Anthracnose, a New Disease of Swallow-Worts Caused by Colletotrichum lineola from Russia

Plant Disease ◽  
2011 ◽  
Vol 95 (12) ◽  
pp. 1586-1586 ◽  
Author(s):  
D. Berner ◽  
C. Cavin ◽  
Z. Mukhina ◽  
D. Kassanelly
Keyword(s):  
United States ◽  
Biological Control ◽  
Dna Sequences ◽  
Aqueous Suspension ◽  
Science Research ◽  
The United States ◽  
Research Unit ◽  
Leaf Spots ◽  
Pure Cultures ◽  
Appressoria Formation

Black swallow-wort, Vincetoxicum nigrum (L.) Moench (= Cynanchum louiseae Kartesz & Gandhi), and pale swallow-wort, V. rossicum (Kleopow) Borhidi (= Cynanchum rossicum (Kleopow) Borhidi), are invasive plants belonging to the family Apocynaceae and are the targets of biological control efforts to control their spread in the United States. In 2010, a disease on a related species, V. scandens Sommier & Levier, was observed in the Krasnodar area of Russia. Disease symptoms were many small, dark red-to-purple leaf spots, approximately 2 to 5 mm in diameter, with white centers. Leaf spots were found on the upper leaf surface. Leaf tips and margins of leaves bearing many of these spots were necrotic. Symptomatic leaves were collected and sent to the BSL-3 containment facility at the Foreign Disease-Weed Science Research Unit (FDWSRU) of the USDA, ARS in Frederick MD. Surface-disinfested symptomatic leaves were incubated at 20 to 25°C in sterile moist chambers. After several days, acervuli and brown setae were observed inside the leaf spots. Pure cultures, designated FDWSRU 10-002, were obtained by transferring spore masses with sterile glass needles onto 20% V8 juice agar. Seeds of V. scandens, collected in Russia, were placed in a freezer at –20°C for 6 weeks and then germinated in sterile petri plates on moist filter paper. The seedlings were then transplanted and grown in a 20°C greenhouse under 12 h of light. Koch's postulates were fulfilled as follows: 2-month-old plants each of V. scandens, V. nigrum, and V. rossicum were inoculated with spores from 2-week-old cultures of isolate 10-002. Plants were inoculated by spraying an aqueous suspension of 106 spores per ml onto each plant until all leaves were wet. Plants were placed in 20 to 24°C dew chambers for 18 h and then placed in a 20°C greenhouse. Two weeks later, diseased leaves with the same symptoms observed in the field were harvested from each species, and the fungus was reisolated from seven of seven inoculated V. scandens plants, one of two V. nigrum plants, and four of four V. rossicum plants. Measurements of fungus fruiting structures were taken from cultures grown on synthetic nutrient-poor agar (SNA) (1). Conidiophores were brown, septate, and branched. Conidia were one-celled, hyaline, smooth walled, ovoid to oblong, falcate, and 20.1 to 26.2 × 1.7 to 3.6 μm (mean ± s.d. = 23.5 ± 1.3 × 2.6 ± 0.4 μm). Lengths of the conidia conformed to the description of Colletotrichum lineola Corda (1), but the conidia were slightly narrower than described. To induce appressoria formation, approximately 104 conidia were placed on sterile dialysis membranes on top of SNA in petri dishes that were wrapped in foil and incubated at 24°C for 24 h. After this time, appressoria were observed with a microscope at ×400 magnification. The appressoria were dark brown, smooth walled, ellipsoidal, and 5.5 to 25.5 × 3.6 to 12.1 μm (mean ± s.d. = 13.4 ± 4.0 × 7.3 ± 2.1 μm), which conformed to the description of appressoria of C. lineola Corda (1). DNA sequences of ITS1, 5.8S, and ITS2 were submitted to GenBank (No. HQ731491), and after BLAST analysis, aligned 100% to 15 previously identified isolates of C. lineola in GenBank. Voucher specimens of the fungus have been deposited in the U.S. National Fungus Collection and were designated as BPI 881105 and BPI 881106. Host range and efficacy tests are planned to determine the suitability of C. lineola for biological control of swallow-worts in the United States. Reference: (1) U. Damm et al. Fungal Divers. 39:45, 2009.

scholarly journals First Report of Anthracnose of Salsola tragus Caused by Colletotrichum gloeosporioides in Russia

Plant Disease ◽  
2008 ◽  
Vol 92 (9) ◽  
pp. 1366-1366 ◽  
Author(s):  
T. Kolomiets ◽  
O. Skatenok ◽  
A. Alexandrova ◽  
Z. Mukhina ◽  
T. Matveeva ◽  
...  
Keyword(s):  
Colletotrichum Gloeosporioides ◽  
Science Research ◽  
Research Unit ◽  
Internal Transcribed Spacers ◽  
Conidial Suspension ◽  
Voucher Specimen ◽  
First Report ◽  
Glucose Agar ◽  
Stems And Leaves ◽  
C 30

In October of 2006, dying Salsola tragus L. (Russian thistle, tumbleweed), family Chenopodiaceae, plants were found along the Azov Sea at Chushka, Russia. Approximately 40 plants in the area were diseased and almost 80% of these were dying. Plants were approximately 1 m tall × 0.5 m wide. Dying plants had irregular, necrotic lesions along the length of the stems. Leaves of these plants were also necrotic. Lesions on stems and leaves were dark brown and usually coalesced. Diseased stems were cut into 3- to 5-mm pieces, disinfested in 70% ethyl alcohol, and then placed onto the surface of potato glucose agar (PGA). Numerous, waxy, subepidermal acervuli with 110 μm long (mean) black setae were observed in all of the lesions after 2 to 3 days. Conidiophores were simple, short, and erect. Conidia were one-celled, hyaline, ovoid to oblong, falcate to straight, and measured 12.9 to 18.0 × 2.8 to 5.5 μm (mean 15.6 × 4.2 μm). Appressoria formed 24 h after placing conidia on a dialysis membrane over 20% V8 juice agar. Appressoria measured 4.0 to 13.9 × 2.4 to 8.8 μm (mean 7.0 × 5.2 μm). These characters conformed to the description of Colletotrichum gloeosporioides (Penz.) Penz. & Sacc. in Penz. (1). A voucher specimen was deposited with the U.S. National Fungus Collections, Beltsville, MD (BPI 878389). Nucleotide sequences for the internal transcribed spacers (ITS 1 and 2) were deposited in GenBank (Accession No. EU530697) and aligned with ITS sequences of two other isolates from S. tragus. There was 100% similarity to each isolate, one from Greece (Accession No. DQ344621) and one from Hungary (Accession No. EU805538). Axenic cultures on PGA were sent to the Foreign Disease-Weed Science Research Unit, USDA, ARS, Fort Detrick, MD for testing in quarantine. Conidia were harvested from 14-day-old cultures grown on 20% V8 juice agar, and healthy stems and leaves of 30-day-old plants of S. tragus (13 plants) were spray inoculated with an aqueous conidial suspension of 1.0 × 106 conidia/ml plus 0.1% v/v polysorbate 20. Another 13 control plants were sprayed with water and surfactant without conidia. Plants were placed in an environmental chamber at 100% humidity for 16 h in the dark at 25°C. After approximately 24 h, all plants were transferred to a greenhouse at 20 to 25°C, 30 to 50% relative humidity, and natural light augmented by 12-h light periods with 500 W sodium vapor lights. Lesions developed on stems of all inoculated plants after 7 days. After 14 days, nine plants were dead and all inoculated plants were dead after 3 weeks. No symptoms developed on control plants. C. gloeosporioides was reisolated from stem pieces of all inoculated plants, and the morphology of the reisolated pathogen was the same as that of the initially isolated pathogen. To our knowledge, this is the first report of anthracnose caused by C. gloeosporioides on S. tragus in Russia. Reference: (1) B. C. Sutton. Page 15 in: Colletotrichum Biology, Pathology and Control. J. A. Bailey and M. J. Jeger, eds. CAB International, Wallingford, UK, 1992.

scholarly journals First Report of Zonate Leaf Spot Caused by Hinomyces moricola on Japanese Hop in Korea

Plant Disease ◽  
2013 ◽  
Vol 97 (8) ◽  
pp. 1117-1117 ◽  
Author(s):  
S. E. Cho ◽  
J. H. Park ◽  
S. H. Hong ◽  
H. D. Shin
Keyword(s):  
Its Region ◽  
The United States ◽  
Infected Leaf ◽  
Invasive Weed ◽  
Voucher Specimen ◽  
First Report ◽  
Leaf Spots ◽  
Initial Symptoms ◽  
Wide Range ◽  
Humulus Japonicus

Japanese hop (Humulus japonicus Siebold & Zucc. = H. scandens (Lour.) Merr.), native to East Asia, is an annual, climbing or trailing vine. The vines can spread to cover large areas of open ground or low vegetation, eventually blanketing the land and vegetation. Pollen of H. japonicus is allergenic, and this species is considered as one of the important causes of pollinosis in Korea and China. It is a notorious invasive weed in the United States and also in France, Hungary, and Italy (1). In September 2012, zonate leaf spots were observed on Japanese hops growing in wetlands in Yeongdong County of Korea. A voucher specimen was preserved in the Korea University Herbarium (KUS-F26901). Initial symptoms included grayish-green to grayish-brown spots without border lines. As the lesions enlarged, they coalesced, leading to leaf blight. Sporophores on the leaf lesions were dominantly hypophyllous, rarely epiphyllous, solitary, erect, easily detachable, and as long as 700 μm. The upper portion of the sporophores consisted of a pyramidal head was ventricose, 320 to 520 μm long and 110 to 150 μm wide. The fungus was isolated from leaf lesions and maintained on potato dextrose agar (PDA). Sclerotia were produced on PDA after 4 to 5 weeks at 18°C without light, but conidia were not observed in culture. These morphological and cultural characteristics were consistent with those of Hinomyces moricola (I. Hino) Narumi-Saito & Y. Harada (= Cristulariella moricola (I. Hino) Redhead) (3,4). An isolate was preserved in the Korean Agricultural Culture Collection (Accession No. KACC46955). Genomic DNA was extracted using the DNeasy Plant Mini DNA Extraction Kit (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 452 bp was deposited in GenBank (Accession No. KC460209). A BLAST search in GenBank revealed that the sequence showed an exact match with those of C. moricola (JQ036181 ex Acer negundo and JQ036182 ex Glycine max). To determine the pathogenicity of the fungus, according to the procedure of Cho et al. (2), sporophores with the pyramidal head were carefully detached from a lesion on the naturally infected leaf using a needle. Each sporophore was transferred individually onto five places of four detached healthy leaves. The leaves were placed in dew chambers and incubated at 16°C. Symptoms were observed after 2 days on all inoculated leaves. A number of sporophores and immature sclerotia which were morphologically identical to the ones observed in the field were formed on the abaxial surface of the leaf 2 weeks after inoculation. The pathogen was reisolated from lesions on the inoculated leaves, confirming Koch's postulates. No symptoms were observed on the control leaves kept in humid chambers for 2 weeks. H. moricola was known to cause zonate leaf spots and defoliation on a wide range of woody and annual plants (3). To the best of our knowledge, this is the first report of Hinomyces infection on Japanese hops in Korea. References: (1) Anonymous. Humulus japonicus (Cannabaceae): Japanese hop. Eur. Medit. Plant Prot. Org. (EPPO). 2012. (2) S. E. Cho et al. Plant Dis. 96:906, 2012. (3) D. F. Farr and A. Y. Rossman. Fungal Databases. Syst. Mycol. Microbiol. Lab., Online publication, ARS, USDA, Retrieved December 8, 2012. (4) S. A. Redhead. Can. J. Bot. 53:700, 1975.

scholarly journals First Report of Anthracnose of Mile-a-Minute (Persicaria perfoliata) Caused by Colletotrichum cf. gloeosporioides in Turkey

Plant Disease ◽  
2012 ◽  
Vol 96 (10) ◽  
pp. 1578-1578
Author(s):  
D. K. Berner ◽  
C. A. Cavin ◽  
I. Erper ◽  
B. Tunali
Keyword(s):  
Biological Control ◽  
Rating Scale ◽  
Biological Control Agent ◽  
Aqueous Suspension ◽  
Botanical Garden ◽  
Control Agent ◽  
Internal Transcribed Spacers ◽  
Voucher Specimen ◽  
First Report ◽  
Persicaria Perfoliata

Mile-a-minute (Persicaria perfoliata (L.) H. Gross; family: Polygonaceae) is an exotic annual barbed vine that has invaded the northeastern USA and Oregon (2). In July of 2010, in a search for potential biological control pathogens (3), diseased P. perfoliata plants were found along the Firtina River near Ardesen, Turkey. Symptoms were irregular dark necrotic lesions along leaf margins and smaller irregular reddish lesions on the lamellae of leaves. Symptomatic leaves were sent to the quarantine facility of FDWSRU, USDA, ARS in Ft. Detrick, MD, for pathogen isolation and testing. Symptomatic leaves were excised, surface disinfested in 0.615% NaOCl, and then incubated for 2 to 3 days in sterile moist chambers at 20 to 25°C. Numerous waxy sub-epidermal acervuli with 84-μm-long (mean) black setae were observed in all of the lesions after 2 to 3 days of incubation. Conidiophores within acervuli were simple, short, and erect. Conidia were one-celled, hyaline, guttulate, subcylindrical, straight, 12.3 to 18.9 × 3.0 to 4.6 μm (mean 14.3 × 3.7 μm). Pure cultures were obtained by transferring conidia onto 20% V-8 juice agar. Appressoria, formed 24 h after placing conidia on dialysis membrane over V-8 juice agar, were smooth, clavate, aseptate, regular in outline, and 6.4 to 10.0 × 5.1 to 7.2 μm (mean 7.5 × 6.6 μm). These characters conformed to the description of Colletotrichum gloeosporioides (Penz.) Penz. & Sacc. (1). A voucher specimen was deposited in the U.S. National Fungus Collections (BPI 882461). Nucleotide sequences for the internal transcribed spacers (ITS 1 and 2), directly sequenced from ITS 1 and ITS 4 standard primers (4), were deposited in GenBank (JN887693). A comparison of these sequences with ITS 1 and 2 sequences of the C. gloeosporioides epitype IMI 356878 (GenBank EU 371022) (1) using BLAST found 479 of 482 identities with no gaps. Conidia from 14-day-old cultures, in an aqueous suspension of 1.0 × 106 conidia ml–1, were spray-inoculated onto healthy stems and leaves of twenty 30-day-old P. perfoliata plants. Another 10 plants were not inoculated. All plants were placed in a dew chamber at 25°C for 16 h with no lighting. They were then placed in a 20 to 25°C greenhouse with a 14-h photoperiod. Light was generated using 400W sodium vapor lights. Lesions developed on leaves and stems of all inoculated plants after 7 days, and symptoms were the same as observed in the field. Each plant was rated weekly for disease severity on a 0 to 10 rating scale where 0 = no disease symptoms and 10 = 100% symptomatic tissue. After 28 days, the average disease rating of inoculated plants was 3.95 ± 0.94. No disease developed on noninoculated plants. C. gloeosporioides was reisolated from all inoculated plants. Host range tests will determine the potential of this isolate as a biological control agent for P. perfoliata. To our knowledge, this is the first report of anthracnose caused by C. gloeosporioides on P. perfoliata. References: (1) P. F. Cannon et al. Mycotaxon 104:189, 2008. (2) J. T. Kartesz and C. A. Meacham. Synthesis of the North American Flora, Version 1.0., North Carolina Botanical Garden, Chapel Hill, N.C. 1999. (3) D. L. Price et al. Environ. Entomol. 32:229, 2003. (4) T. J. White et al. PCR Protocols: A Guide to Methods and Applications. Academic Press, Inc., San Diego, CA, 1990.

scholarly journals First Report of Leaf Spot Caused by Colletotrichum cf. linicola on Field Bindweed in Turkey

Plant Disease ◽  
2008 ◽  
Vol 92 (2) ◽  
pp. 316-316 ◽  
Author(s):  
B. Tunali ◽  
D. K. Berner ◽  
H. J. Dubin
Keyword(s):  
Dna Sequences ◽  
Aqueous Suspension ◽  
Severe Disease ◽  
Leaf Tissue ◽  
Malt Extract ◽  
Voucher Specimen ◽  
First Report ◽  
Wheat Field ◽  
Leaf Spots ◽  
Field Bindweed

Field bindweed (Convolvulus arvensis L., Convolvulaceae) is one of the most problematic weeds in the world (1) and a target of biological control efforts (2). In the summer of 2006, dying field bindweed plants were found in a wheat field near Bafra, Turkey (41°21.197′N, 36°12.524′E). Plants had water-soaked lesions that developed into necrotic leaf spots on most of the leaves, particularly along the leaf margins, and on some stems. In most cases, the leaf spots coalesced, causing the leaves and later plants to wilt and die. Diseased leaves and stems were taken to the Phytopathology Laboratory of the Faculty of Agriculture, Ondokuz Mayis University, Samsun, Turkey. Diseased tissue was surface disinfested and placed on moist filter paper in petri dishes. Numerous acervuli with setae and conidia typical of a Colletotrichum sp. were observed after 2 to 5 days. A fungus, designated 06-01, was isolated from the diseased leaves. Stems and leaves of seven 12-week-old plants were spray inoculated in the laboratory with an aqueous suspension of conidia (106 spores per ml; 10 ml per plant) harvested from 6- to 8-day-old cultures grown on malt extract agar. The plants and two noninoculated checks were placed in a dew chamber at 22°C in darkness and continuous dew. After 48 h, plants from the dew chamber were moved to a greenhouse bench. All plants were watered twice daily. Symptoms were observed 5 days after inoculation. No symptoms were observed on noninoculated plants. Isolate 06-01 was reisolated from all inoculated plants. In the field, 20 inoculated plants became diseased after 20 days with approximately 36% diseased leaf tissue from which 06-01 was consistently reisolated. Diseased tissue and cultures of the fungus were sent to the Foreign Disease-Weed Science Research Unit, USDA/ARS, Fort Detrick, MD. The fungus conformed to the description of Colletotrichum linicola Pethybr. & Laff., which was noted as distinct from C. lini (3). The original description is also different than the description of C. lini (Westerdijk) Tochinai by Sutton (4). Acervuli were sparse, subepidermal, and erumpent. Conidia were hyaline, oblong or cylindrical or somewhat spindle-shaped with dull-pointed ends, guttulate, and 14 to 19 × 4 to 5 μm (mean 17 × 4 μm). Conidiophores were short, simple, hyaline, and emerged from subepidermal stroma. Setae were simple, erect, 3-septate, and dark with hyaline tips. DNA sequences were obtained for the internal transcribed spacer regions (GenBank Accession No. EU000060) and compared with other sequences in GenBank. Sequences from 06-01 matched 100% with one isolate of C. linicola and 99% with two other isolates of C. linicola. These isolates formed a unique clade. However, 06-01 was also 99% identical to other species of Colletotrichum. Thus, species identification is inconclusive. Isolate 06-01 is a destructive pathogen on field bindweed, and severe disease can be produced by inoculation of foliage with an aqueous suspension of conidia. To our knowledge, this is the first report of Colletotrichum on field bindweed. A voucher specimen has been deposited with the U.S. National Fungus Collections (BPI 878174). References: (1) L. Holm et al. The World's Worst Weeds. University Hawaii Press, Honolulu, Hawaii, 1977. (2) G. Defago et al. BioControl 46:157, 2001. (3) G. H. Pethybridge and H. A. Lafferty. Sci. Proc. R. Dublin Soc. 15:359, 1918. (4) B. C. Sutton. The Coelomycetes. Commonw. Mycol. Inst., Kew, England, 1980.

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