bluuebunny/crossref_metadata_2025_split huggingface dataset:
First Report of Pyricularia grisea (Gray Leaf Spot) on Perennial Ryegrass (Lolium perenne) in Nevada
Authors: Wong F. P. , de la Cerda K. A. 
Published: May 2007

In August of 2005, a golf course in Las Vegas, NV reported turf loss from an unknown disease on perennial ryegrass fairways. Samples from this course were examined, and diseased plants were found covered with lesions and sporulation typical of gray leaf spot as caused by Pyricularia grisea (Cooke) Sacc. With petroleum jelly, sporulating leaves were attached to the inside top surface of 100-mm petri dishes filled with 15 ml of 1.5% water agar. Conidia were allowed to drop onto the agar surface and 24 h later, individual germinating pyriform conidia were transferred to petri dishes containing one-quarter-strength potato dextrose agar (¼-PDA) with the aid of a fine needle and stereomicroscope. Isolates of the fungus were maintained at 28°C with constant fluorescent light. Isolates were examined 7 to 10 days later, and morphology and conidia production were consistent with that described previously for P. grisea (1). Koch's postulates were performed using a single isolate (SSGC-1.1) grown for 14 days on ¼-PDA. The petri dish was flooded with 15 ml of sterile distilled water plus 0.05% Tween 20 and conidia dislodged into the solution with a rubber policeman to obtain a solution of approximately 5 × 103 conidia per ml. Using a modified thin-layer chromatography plate sprayer, the solution was misted onto six pots of 6-week-old perennial ryegrass (a mixture of approximately 33% each of varieties ‘Kokomo’, ‘Cabo’ and ‘Secretaria’), seeded at a density of 2 kg per 93 m2 grown in 4- × 4-cm plastic pots filled with University of California soil mix. As a control treatment, six pots of perennial ryegrass (grown as previously described) were treated with water plus 0.05% Tween 20 only. Pots of plants were placed into closed, translucent, plastic containers lined with wet paper towels to provide a moist environment and held at 30°C for 48 h. Pots of plants were transferred to an incubator set at 30°C and 80% relative humidity with 12 h of alternating light and dark cycles. Four days after inoculation, plants misted with conidia developed symptoms typical of gray leaf spot. Plants were again placed into closed plastic containers lined with wet paper towels for 24 h, at which time, lesions on symptomatic plants developed abundant conidia characteristic of P. grisea. Water-only treated plants did not show any symptoms or signs of disease. P. grisea was reisolated from sporulating leaves as described above. The disease has been spreading in the midwestern and northeastern United States since first reported in 1991 on perennial ryegrass in Pennsylvania. It has only recently been found on turfgrass in California (2), and to our knowledge, this is the first report of this pathogen on perennial ryegrass in Nevada. References: (1) M. B. Ellis. Dematiaceous Hyphomycetes. CMI, Kew, Surrey, UK, 1971. (2) W. Uddin et al. Plant Dis. 86:75, 2002.
Mycosphaerella fijiensis, Causal Agent of Black Sigatoka of Musa spp. Found in Puerto Rico and Identified by Polymerase Chain Reaction
Authors: Irish B. M. , Goenaga R. , Ploetz R. C. 
Published: May 2007

Black Sigatoka, also known as black leaf streak, is caused by Mycosphaerella fijiensis Morelet (anamorph Pseudocercospora fijiensis (Morelet) Deighton). It is the most significant disease of bananas and plantains (Musa spp.) because most of the economically important cultivars of exported and staple commodities are highly susceptible. The Caribbean is one of the few regions of the world where black Sigatoka is not widespread. Black Sigatoka has been reported in the Bahamas, Cuba, Hispaniola, and Jamaica (2). Yellow Sigatoka, caused by M. musicola Leach (anamorph P. musae (Zimm.) Deighton), has been recognized in Puerto Rico since 1938-1939 (3). In August 2004, symptoms resembling black Sigatoka were first observed in Añasco, Puerto Rico by extension personnel from the University of Puerto Rico. Since black and yellow Sigatoka produce similar disease symptoms, a survey was conducted in the western banana- and plantain-production region of Puerto Rico to confirm the presence of black Sigatoka. Leaf samples were collected from production fields near the towns of Las Marias, Maricao, and Añasco. Single-ascospore isolates were recovered using the discharge technique from moistened pseudothecia in necrotic lesions that were inverted over water agar, and ascospores were transferred to potato dextrose agar. The isolates were subcultured in potato dextrose broth for mycelium production. DNA was isolated from mycelium with the FastDNA kit (Q-Biogen, Irvine, CA) for 19 isolates. Internal transcribed spacer as well as the 5.8s rDNA regions were polymerase chain reaction amplified with primers specific to M. fijiensis or M. musicola (1). Amplification products (˜1,100 bp) were observed for 18 of the 19 isolates, 6 of which were M. fijiensis and the remaining 12 were M. musicola, while the positive controls for both species were also amplified with the respective primer pairs. M. fijiensis was recovered from production fields close to all three towns. The source of M. fijiensis in Puerto Rico is unclear, but it may have originated from introduced leaf material and/or wind dispersed ascospores from neighboring countries. The presence of black Sigatoka in Puerto Rico will most likely increase production costs where fungicide applications will be needed to maintain yields. The USDA-ARS, Tropical Agriculture Research Station is the official Musa spp. germplasm repository for the National Plant Germplasm System. As such, efforts are underway to introduce and evaluate black Sigatoka disease-resistant clones that can satisfy local and export market criteria. References: (1) A. Johnasen. Detection of Sigatoka leaf spot pathogens of banana by the polymerase chain reaction. Chatman, UK, Natural Resource Institute, 1997. (2) R. C. Ploetz. Plant Dis. 88:772, 2004. (3) R. H. Stover. Trop. Agric. Trinidad. 39:327, 1962.
Frankliniella cephalica, a New Vector for Tomato spotted wilt virus
Authors: Ohnishi J. , Katsuzaki H. , Tsuda S. , Sakurai T. , Akutsu Katsumi , Murai T. 
Published: May 2007

Frankliniella cephalica (Crawford) is an invasive species of thrips found in the islands of Yaeyama in the Okinawa Prefecture, Japan. During the late 1990s to early 2000s, a species of thrips was isolated from wild flowers of Bidens pilosa L. and Ipomoea batatas L. growing close to cultivated fields. They were subsequently identified as F. cephalica using fine morphological characteristics with the help of Steve Nakahara (U.S. Department of Agriculture, Beltsville, MD) and Laurence Mound (CSIRO, Australia). Voucher specimens were deposited in the Laboratory of Insect Resources, Faculty of Agriculture, Tokyo University of Agriculture by Shuji Okajima (2). We investigated the ability of F. cephalica to vector Tomato spotted wilt virus (TSWV) by experimentally determining virus transmission efficiency. Newly hatched larvae as much as 12 h old underwent a viral acquisition-access period (AAP) of 24 h, during which they fed on the leaves of Datura stramonium infected with TSWV-O, a Japanese type isolate. Transmission efficiency of adults 4 days after emergence from molt (14 days after the AAP) was determined by a petunia leaf disk assay (3) in which the adults were individually allowed to feed for successive 24-h inoculation access periods (IAP) on two different leaf disks of Petunia × hybrida cv. Polo Blue. Transmission of the virus by the adults was considered positive if at least one of the leaf disks showed viral necrotic spot. We tested 20 randomly selected leaf disks with clear necrotic spots using a simplified rapid immunofilter paper assay. All selected disks were positive for TWSV. The transmission efficiencies were 24.6% for female (n = 57) and 54.4% for male (n = 125) adults. The efficiency was significantly different between sexes (Fisher's exact probability test, P < 0.001). We also examined changes in the virus infection site at different developmental stages in thrips using immunofluorescence microscopy with a polyclonal antibody to N protein of the virus (4). After a 6-h AAP feeding by first instar larvae, the virus was found initially to infect the epithelial cells and then spread throughout the midgut tissue in the second instar larvae 5 days after acquisition of the virus. In viruliferous adults, the virus was present in the salivary glands and on the basement membrane of the midgut tissue. These data indicate that F. cephalica is a new insect vector for TSWV. F. cephalica is a major insect pest of tropical crops in tropical and subtropical coastal belts (1). The presence of a thrips vector in weed hosts surrounding cultivated fields might increase the chance of crops in this habitat becoming infected with viruses. References: (1) M. Lamberts and J. H. Crane. Page 337 in: Advances in New Crops. J. Janick and J. E. Simon, eds. Timber Press, Portland, OR, 1990. (2) M. Masumoto and S. Okajima. Jpn. J. Appl. Entomol. Zool. 48:225, 2004. (3) T. Sakurai et al. Appl. Entomol. Zool. 39:71, 2004. (4) S. Tsuda et al. Ann. Phytopathol. Soc. Jpn. 60:216, 1994.
First Report of Root-Knot Nematode Meloidogyne javanica on Chrysanthemum in Colombia
Authors: Agudelo P. A. , Lewis S. A. , Abril M. A. 
Published: May 2007

Severe plant stunting, chlorosis, and extensive root galling were observed on chrysanthemum (Dendrathema grandiflora cv. Yellow Vero) in a commercial cut-flower production facility in Rionegro, Antioquia, northwestern Colombia. Examination of the root samples from selected infected plants revealed the presence of abundant root-knot nematodes. Juveniles, males, and females were extracted for species identification using morphological characteristics. Identification was confirmed by perineal patterns and esterase phenotype analysis of females. All methods of identification were consistent with typical Meloidogyne javanica. No other root-knot nematode species were found on this farm, but the presence of other Meloidogyne species in the region is possible. Root-knot nematodes have been reported to cause economic losses in cut-flower plantations in Colombia (1), but there are no reports of the species involved. M. javanica has an extensive host range and wide distribution. The identification and distribution of M. javanica in chrysanthemum production is relevant because nematode-fungus interactions may depend on the nematode species involved. Only M. javanica, and not M. hapla or M. incognita, has been found to increase the severity of Fusarium wilt on chrysanthemum (2). To our knowledge, this is the first report of M. javanica on chrysanthemum in Colombia. References: (1) G. Arbeláez. Acta Hortic. 482:91, 1999. (2) A. W. Johnson and R. H. Littrell. J. Nematol. 1:122. 1969.
Sawadaea tulasnei Powdery Mildew of Norway Maple (Acer platanoides) in North America
Authors: Weiland J. , Stanosz G. 
Published: May 2007

Norway maple leaves bearing powdery mildew were collected from one location in the fall of 2003 and four locations (as much as 1.5 km apart) in the fall of 2005 in Buffalo, NY. No powdery mildew was observed on leaves collected from sugar maples (Acer saccharum) that were present in the vicinity of affected Norway maples at two locations. Trees were located along streets and in yards. Diseased leaves were present throughout tree crowns but lower leaves were more commonly affected. White mycelium was present in irregular, discrete, scattered spots only on the upper surface of leaves and on both sides of wings of samaras. Typically, <10% of the upper leaf area bore visible mycelium. Cleistothecia were present singly or in groups on the mycelium. Morphology of cleistothecia on leaves collected each year, including simple and bifid appendages with uncinate to circinate apices, was sufficient to identify the pathogen to the genus Sawadaea (1). Other characteristics were not sufficiently distinct to make an identification of S. bicornis or S. tulasnei (1), each a European species found on Acer spp. However, a sample from 2003 was supplied by the authors for use in a study of phylogeny of the genus (2) that served as a first report of the species in the United States. Analysis of nuclear rDNA ITS sequence of this specimen (GenBank Accession No. AB193390) placed the sample in a clade with S. tulasnei specimens from Europe. In the same study, powdery mildew samples from Acer spp. in Ohio and Montreal, Canada also were placed in this clade. Thus, occurrence of S. tulasnei in North America is confirmed. S. bicornis was recently identified (based on morphology) on Norway maple in the western United States (3). Specimens from Buffalo, NY have been deposited in the U.S. National Fungus Collections (BPI 871210). References: (1) U. Braun. The Powdery Mildews (Erysiphales) of Europe. Gustav Fischer Verlag, Jena-Stuttgart-New York, 1995. (2) S. Hirose et al. Mycol. Res. 109:912, 2005. (3) C. Nischwitz and G. Newcombe. Plant Dis. 87:451, 2003.
Molecular Characterization of a Distinct Tomato-Infecting Begomovirus Associated with Yellow Leaf Curl Diseased Tomato in Lembang, Java Island of Indonesia
Authors: Tsai W. S. , Shih S. L. , Green S. K. , Akkermans D. , Jan F.-J. 
Published: May 2007

Three distinct tomato-infecting begomoviruses have been identified from Indonesia (GenBank Accessions Nos. AB100304, AB100305, and DQ083765). Severe yellow leaf curl epidemics have been observed on tomato on Java Island since the late 1990s. Viral DNA was extracted (2) from one such sample collected in Lembang, West Java in 1998. Polymerase chain reaction with previously described primers was used to detect the presence of geminiviral DNA-A (4), DNA-B (3), and associated satellite DNA (1). The predicted 1.4-kb DNA-A fragment was amplified with the general primer pair PAL1v1978/PAR1c715 and then cloned and sequenced. DNA-B and satellite DNA were not detected in the sample. On the basis of the partial DNA-A sequences, specific primers were designed to amplify and sequence the complete DNA-A component (2,762 nucleotides, GenBank Accession No. AF189018). The DNA-A sequence contained the geminivirus-conserved nanosequence TAATATTAC in the loop of the hairpin structure of the intergenic region and six open reading frames including two in the virus sense and four in the complementary sense. Pairwise comparison of the full-length DNA-A sequence with those of other begomoviruses available in the GenBank database was done by the MegAlign software (DNASTAR, Inc, Madison, WI). Highest nucleotide sequence identity (74.1%) was with Tomato leaf curl Mayotte virus-[Kahani] (GenBank Accession No. AJ865340). Comparison of the full-length DNA-A sequence with the three above mentioned tomato-infecting begomoviruses from Indonesia also showed less than 71% nucleotide sequence identities. Because the DNA-A sequence had less than 89% identity with other begomoviruses, it should be classified as a distinct virus according to the International Committee on Taxonomy of Viruses. The name Tomato yellow leaf curl Indonesia virus-[Lembang] (TYLCIDV-[Lem]) is proposed. The presence of at least four distinct tomato-infecting begeminiviruses on Java Island needs to be considered when developing tomato cultivars with stable resistance to tomato (yellow) leaf curl disease. References: (1) R. W. Briddon et al. Virology 312:106, 2003. (2) R. L. Gilbertson et al. J. Gen. Virol. 72:2843, 1991. (3) S. K. Green et al. Plant Dis. 85:1286, 2001. (4) M. R. Rojas et al. Plant Dis. 77:340, 1993.
First Report of Rust Caused by Phakopsora pachyrhizi on Soybean and Kudzu in Texas
Authors: Isakeit T. , Miller M. E. , Saldaña R. , Barnes L. W. , McKemy J. M. , Palm M. E. , Zeller K. A. , DeVries-Paterson R. , Levy L. 
Published: May 2007

The Asian soybean rust fungus, Phakopsora pachyrhizi H. Sydow & Sydow, was found on a 0.4-ha patch of kudzu (Pueraria lobata) near Dayton (Liberty County) in East Texas on November 2, 2005. Nearly 100% of the 300 leaflets examined were diseased with severity ranging from 5 to >100 lesions per leaflet. Eleven soybean fields as much as 20 km away were scouted and no infected plants were found. Asian soybean rust was also found on a 0.4-ha field of soybean (Glycine max cv. Vernal) on February 14, 2006 at the Texas A&M Agricultural Experiment Station in Weslaco (Hidalgo County) in the Lower Rio Grande Valley (LRGV) of Texas. Disease incidence was 100% (severity ranging from 5 to >100 lesions per leaflet) on 50 younger plants with green leaves along the edges of the field, whereas most of the plants in this field had senesced. These plants were not symptomatic and were at the R6 stage (full seed) when this field was previously scouted on December 19, 2005. Lesions on leaflets of kudzu and soybean were small and angular with erumpent uredinia typical of P. pachyrhizi. Urediniospores were ovoid or globose, hyaline, and measured 25 to 30 × 14 to 21 μm. Leaf samples with pustules were positive for P. pachyrhizi using enzyme-linked immunosorbent assay (ELISA) (Envirologix, Portland, ME). Morphological and polymerase chain reaction (PCR) identification of P. pachyrhizi from kudzu and soybean samples were confirmed by the USDA-APHIS-PPQ NIS and CPHST laboratories in Beltsville, MD as previously described (2). The kudzu in East Texas is not likely to support overwintering of the pathogen because it usually dies back during the winter. Leaves at this site were dead by January 17, 2006. This is the southernmost infestation of kudzu in Texas known to us. In contrast, the LRGV has a subtropical climate that would favor year-round survival of the fungus (3). This area, where 120 to 160 ha of soybeans are grown, may be a source of inoculum for soybean rust epidemics in the Midwest. Spore movement would follow the same pattern as seen with cereal rusts (1). However, soybeans are typically absent from the LRGV between late December and early March, so survival of the fungus during this interval would require other hosts. Regardless of whether the fungus overwinters here, or moves in from elsewhere, the LRGV spring crop could serve as an early indicator of a potential rust epidemic. References: (1) M. G. Eversmeyer and C. L. Kramer. Annu. Rev. Phytopathol. 38:491, 2000. (2) J. M. Mullen et al. Plant Dis. 90:112, 2006. (3) S. Pivonia et al. Plant Dis. 89:678, 2005.
First Report of Phakopsora pachyrhizi, the Causal Agent of Asian Soybean Rust, on Florida Beggarweed in the United States
Authors: Sconyers L. E. , Kemerait R. C. , Brock J. H. , Gitaitis R. D. , Sanders F. H. , Phillips D. V. , Jost P. H. 
Published: May 2007

Phakopsora pachyrhizi Syd. & P. Syd., which causes Asian soybean rust (SBR), was observed on Florida beggarweed, Desmodium tortuosum (Sw) DC., in Attapulgus, GA during late October and early November 2005. Tan to brown lesions (<1.0 mm in diameter) consistent with symptoms of SBR (2) were observed on older leaves of several plants collected near an SBR-infected soybean trial. Dissection (40 to 60×) and compound microscopy (×200 to 400) revealed conical pustules and ellipsoid, echinulate urediniospores (average size 15 × 20 μm) on the abaxial leaf surface. Polymerase chain reaction (PCR) (primers Ppm1 and Ppa2) (1) was conducted on four samples to confirm identification of P. pachyrhizi or P. meibomiae. Three were positive for P. pachyrhizi, and one was negative for both species. Using morphology and real-time PCR, SBR was confirmed as P. pachyrhizi by the USDA/APHIS in Beltsville, MD. Six noninfected Florida beggarweed plants were transplanted to pots during December 2005 and grown at 22 to 24°C in a greenhouse. On 11 January 2006, a water suspension of urediniospores collected from SBR-infected soybeans (1 × 105 spores per ml) was spray inoculated on all leaves to almost runoff and incubated for 48 h in a plastic humidity chamber. Lesions, pustules, and urediniospores consistent with SBR (2) were observed on 3 February 2006. A PCR assay was conducted on six samples from the infected greenhouse plants and all were positive for P. pachyrhizi. Florida beggarweed is widespread in the southern United States and may serve as an additional overwintering source for P. pachyrhizi and a potential inoculum source for the soybean crop. References: (1) R. D. Fredrick et al. Phytopathology 92:217, 2002. (2) J. B. Sinclair and G. L. Hartman. Soybean rust. Pages 25–26 in: Compendium of Soybean Diseases. 4th ed. G. L. Hartman et al., eds. The American Phytopathological Society, St. Paul, MN, 1999.
A Yellow Mosaic Disease of Soybean in Northern India is Caused by Cotton leaf curl Kokhran virus
Authors: Raj S. K. , Khan M. S. , Snehi S. K. , Srivastava S. , Singh H. B. 
Published: May 2007

Soybean, Glycine max (L.) Merr., is a protein- and oil-rich crop cultivated in India and abroad. A yellow mosaic disease was observed on soybean with 80 to 90% disease incidence during August 2005 at fields of the National Botanical Research Institute, Lucknow, in northern India. Soybean plants were found to be infested with whiteflies (Bemisia tabaci) suggesting begomovirus etiology. The disease agent was transmitted experimentally by whiteflies, and symptoms developed after 23 days. Total DNA was isolated from 51 leaf samples collected from 42 symptomatic and 9 asymptomatic plants. Polymerase chain reaction was performed using begomovirus coat protein-specific primers 5′-ATGGCGAA GCGACCAG-3′ and 5′-TTAATTTGTGACCGAATCAT-3′ (AM180920/ AM180921). An amplicon of the expected size (~800 bp) was obtained in all 42 symptomatic leaves but not from any of the nine asymptomatic leaf samples. The amplicon was cloned, and the identical sequence of three clones was submitted to GenBank (Accession No. DQ343283). BLAST search of nucleotide sequences revealed 95% identity with Cotton leaf curl Kokhran virus (CLCKV) (GenBank Accession Nos. AJ002449, AJ002448, AJ496286, and AY456683) and 57% identity with Mungbean yellow mosaic India virus (MYMIV-Sb, GenBank Accession No. AY049772). Results indicated that the virus associated with yellow mosaic disease of soybean is an isolate of CLCKV rather than MYMIV-Sb (1) reported earlier on soybean from northern India. To our knowledge, this is the first report of soybean as a new host of Cotton leaf curl Kokhran virus. Reference: (1) K. S. Usharani et al. Curr. Sci. 86:845, 2004.