bluuebunny/crossref_metadata_2025_split huggingface dataset:
First Report of Globodera tabacum Infecting Tobacco Plants in Quebec, Canada
Authors: Bélair G. , Miller S. 
Published: May 2007

The tobacco cyst nematode Globodera tabacum (Lownsbery & Lowns-bery) Behrens is a damaging soilborne pathogen of shade and broadleaf tobacco in the United States (2). Nematode infection of roots can cause dramatic stunting, yield loss, and reduce leaf quality. G. tabacum is considered a complex of three cyst nematodes not distinguishable morphologically including G. tabacum tabacum, G. tabacum virginiae, and G. tabacum solanacearum. During 1998, infested flue-cured tobacco plants were harvested in the Lanaudière Region near Montreal, Quebec. Cysts recovered from roots and soil were identified by morphological and morphometric analysis of mature cysts and unhatched juveniles. Although multiple interceptions on nursery stock entering Quebec from infested nurseries in Hartford County, Connecticut from 1974 to 1986 have been recorded (1), to our knowledge, this is the first record of G. tabacum established in Canadian soil. On the basis of historic nematode infestations in this county, it could be inferred that it was G. tabacum tabacum, but further analysis is necessary for definitive subspecies determination. The infested tobacco plants were stunted in the field when compared with noninfested plants. Recently, the production in that area has been abandoned. Because cysts may survive for years in absence of host and also because potato, also a host of G. tabacum, is being introduced on these tobacco farms, it is believed that the distribution of this nematode could expand in the future in this part of the country. References: (1) Agriculture Canada Canadian Plant Quarantine Annual Reports. Intercepted Plant Pests. Publisher (Ottawa): Plant Protection Division, Department of Agriculture, 1967-2000. (2) J. G. Baldwin and M. Mundo-Ocampo. Heteroderinae, cyst- and non-cyst forming nematodes. Page 275 in: Manual of Agricultural Nematology. W. R. Nickle ed. Marcel Dekker Inc., New York, 1991.
First Report of Lolium latent virus in Ryegrass in the United States
Authors: Maroon-Lango C. J. , Hammond J. , Warnke S. , Li R. , Mock R. 
Published: May 2007

Initial reports of the presence of Lolium latent virus (LLV) in Lolium perenne L. and L. multiflorum Lam. breeding clones in Germany, the Netherlands, France (2), and recently the United Kingdom (3,4; described as Ryegrass latent virus prior to identification as LLV) prompted us to evaluate clonally propagated Lolium plants from the United States. Four genetically distinct plants (viz., MF22, MF48, MF125, and MF132) that have been maintained clonally for 5 years from a Lolium perenne × L. multiflorum hybrid population established in the United States exhibited either no symptoms or mild chlorotic flecking that coalesced to form chlorotic to necrotic streaking on the leaves. All four clonal plants tested positive using reverse transcription-polymerase chain reaction (RT-PCR) with the Potexvirus group PCR test (Agdia, Inc., Elkhart, IN), whereas all clones but MF48 tested positive using the Potyvirus group PCR test (Agdia, Inc.). No amplicons were obtained when the same plants were tested for tobamovirus, carlavirus, and closterovirus using appropriate virus group-specific primers. Cloning and sequencing of the potexviral amplicons revealed very high sequence identity with the comparable region of LLV-UK (GenBank Accession No. DQ333886), whereas those of the potyviral amplicons (GenBank Accession Nos. DQ355837 and DQ355838) were nearly identical with the comparable region of Ryegrass mosaic virus (RGMV), a rymovirus first reported from the United States in 1957 (1). Using indirect enzyme-linked immunosorbent assay (ELISA), extracts from all four Lolium clonal propagations tested positive for LLV using the antiserum raised to LLV-Germany (courtesy of Dr. Huth), whereas the potyvirus-positive results from RT-PCR of the three clones were confirmed using indirect ELISA with the broad spectrum potyvirus monoclonal antibody, PTY-1. LLV from singly or dually infected Lolium clones was transmitted to Nicotiana benthamiana Domin. but not to N. tabacum L. by mechanical inoculation. LLV was purified from infected N. benthamiana. Similar sized flexuous rods were observed using electron microscopy in leaf dip samples from Lolium clones and aliquots of the virions purified from N. benthamiana. References: (1) G. W. Bruehl et al. Phytopathology 47:517, 1957. (2) W. Huth et al. Agronomie 15:508, 1995. (3) R. Li et al. Asian Conf. Plant Pathol. 2:89, 2005. (4) C. Maroon-Lango et al. Int. Congr. Virol. 13:63, 2005.
Tissue Necrosis of Sour Cherry Fruits, An Unusual Disease Occurrence Caused by a Phoma sp. in Serbia
Authors: Gavrilović V. , Arsenijević M. 
Published: May 2007

Following frequent rains during May and June of 1999, a high incidence of an unknown disease on sour cherry (Prunus cerasus) fruits was observed in western Serbia (Šabac). Initially, small, water-soaked, dark green spots appeared on the fruit tissue similar to infections caused by Pseudomonas syringae or a Colletotrichum sp. (1,2). Later, spots enlarged, coalesced, and became necrotic and covered most of the fruit surface. The diseased tissue was slightly depressed and fruit shriveled and dried. Approximately 60 to 80% of the total yield was affected. Numerous hyaline, unicellular, and ellipsoidal conidia were observed with a microscope. Orange spore masses often occurred on the necrotic tissue following rain. Symptoms of the disease were not expressed during the dry spring of 2000, but were observed in rainy 2001. The most susceptible cultivar was Haiman's Rubin. Disease symptoms were absent on the domestic cultivar Oblačinska. Placing small necrotic fragments on potato dextrose agar (PDA) resulted in grayish fungal colonies that produced black, globose pycnidia with hyaline, unicellular, and ellipsoidal conidia under daylight conditions that were similar to those formed on necrotic sour cherry fruit in the orchard. At 25°C, colonies covered the entire 9-cm diameter surface of PDA after 5 to 6 days. No teleomorph was observed. Bacterial isolations on nutrient agar were unsuccessful. Unripe sour cherry fruits were punctured with a sterile needle and small colony fragments of the fungus were placed over the wound. Symptoms typical of those on fruit found in orchards were observed after 7 days of incubation at 25°C. No symptoms developed on control fruits punctured with a sterile needle. The fungus was reisolated from the inoculated fruits and shown to be identical to the original strains. On the basis of pathogenicity and morphological characteristics of the strains investigated, the fungus was determined to be a Phoma sp. (3), also known as sour cherry necrosis in other fruit-tree-growing regions. To our knowledge, this is the first report of the fungus on sour cherry fruit in Serbia. References: (1) J. Balaž and M. Arsenijević. Proc.Int. Conf. Plant. Path. Bact. 7:515, 1990. (2) M. Ivanović and D. Ivanović. Zašt. Bilja 201:211, 1992. (3) B. C. Sutton. Pages 379–391 in: Coelomycetes. CMI, Kew, Surrey, England, 1980.
First Report of Alternaria Leaf Spot on Cherry Trees in Greece
Authors: Thomidis T. , Tsipouridis C. 
Published: May 2007

Cherry leaf spot disease caused by Alternaria spp. has been reported in China (1) but never in Greece. The fungus Alternaria alternata (Fr.:Fr.) Keissler (CBS 119115) was isolated on acidified potato dextrose agar (2.5 ml of 85% lactic acid per liter of nutrient medium) from the leaves of cherry cv. A1/5 (hybrid of Prunus avium (L.) L.) at the Pomology Institute Naoussa, Greece in 2005. Microscopic morphology showed acropetal chains of multicellular conidia (dictyoconidia) produced sympodially from simple, sometimes branched, short or elongate conidiophores. Conidia are obclavate, obpyriform, sometimes ovoid or ellipsoidal, often with a short conical or cylindrical beak, pale brown, smooth-walled or verrucose. The percentage of diseased leaves was approximately 30 to 40%. Lesions first appeared on leaves in late spring as small, round, blackish spots and gradually enlarged to 2 to 5 mm in diameter with a brownish purple border. Some spots turned grayish brown, but most underwent a secondary enlargement and become irregular and much darker, acquiring a frogeye appearance. Similar symptoms were also observed on the leaves of cherry hybrids A1/3 and A5 established in the same cherry orchard. Zhu and Chang (1) reported that infected leaves of cherry trees by Alternaria seraci showed holes and resulted in early leaf fall. Symptoms were reproduced in the laboratory by spraying 2-year-old plants (20 plants) at the stage of fullleaf development, planted in pots, of the same cherry hybrid with conidia of the fungus. Aqueous suspension was adjusted to 3 × 10-6 conidia per ml (approximately 100 ml per plant) collected from an isolation of the fungus. Control plants were sprayed with distilled water without conidia. Plants were then placed in a growth chamber at 25°C for 3 months. After the incubation period, some leaves of the inoculated plants developed similar to those previously observed. No disease symptoms were observed in control leaves. Koch's postulates were satisfied after reisolating the fungus. To our knowledge, this is the first report of the occurrence Alternaria leaf spot on cherry trees in Greece. Reference: (1) J. Zhu and Y. Chang. China Fruits 3:9, 2004.
First Report of Root Rot and Stem Canker Caused by Phytophthora cambivora on Noble Fir (Abies procera) for Bough Production in Norway
Authors: Talgø V. , Herrero M. , Toppe B. , Klemsdal S. , Stensvand A. 
Published: May 2007

In 2004, damages resembling those caused by Phytophthora spp. were observed in a 15-year-old bough plantation of noble fir (Abies procera). When removing bark upward from the roots and base of a diseased tree, a reddish brown discoloration with distinct borders to surrounding wood appeared. The discoloration extended approximately 1.5 m above ground, but only on one side of the stem. This resulted in dead basal branches (flagging) on the cankered side of the tree. Other dying trees in the same field did not show flagging symptoms but turned chlorotic to brown after being girdled by the expanding stem canker. Approximately 25% of the trees were dead or dying. Isolations were carried out from the area between healthy and diseased tissue both from roots and base of the stem of the tree with flagging symptoms. Samples were rinsed in running tap water and plated on the Phytophthora selective medium PARP (17 g of cornmeal agar, 10 mg of pimaricin, 250 mg of ampicillin, 10 mg of rifampicin, and 100 mg of pentachloronitrobenzene (PCNB) in 1 liter of water), with and without hymexazol added (50 mg/l). Morphological characters of the isolated Phytophthora sp. included nonpapillate sporangia (37 to 64 μm), internal proliferation, and characteristic hyphal swellings. The isolate was heterothallic and produced amphigynous antheridia when crossed with tester strains of P. cryptogea. The mating type was A2. The internal transcribed spacer (ITS) rDNA sequences were identical to P. cambivora (GenBank Accession No. AY880985). Thus, both morphological characters and DNA analysis supported the species identification. A pathogenesis test to fulfill Koch's postulate was carried out during 2005. Inoculation was done by placing agar with culture in the growth medium close to the roots of noble fir seedlings. Eleven weeks after inoculation, clearly visible stem canker symptoms were observed. The ITS sequences of the reisolated Phytophthora sp. were determined and found identical to P. cambivora. P. cambivora was reported to cause root rot and stem canker in a noble fir Christmas tree plantation in the United States (1). P. citricola and P. citrophthora are known to cause problems on Lawson Falsecypress/Port-Orford-cedar (Chamaecyparis lawsoniana) in Norway, but damages by Phytophthora spp. have never been reported in Abies spp. plantations or forest stands in Norway. Currently, we are also working on Phytophthora problems discovered in two different Christmas tree plantations (A. lasiocarpa and A. nordmanniana). Reference: (1) G. A. Chastagner et al. Plant Dis. 79:290, 1995.
First Report of Cotton Leaf Curl Disease in Central and Southern Sindh Province in Pakistan
Authors: Mansoor S. , Amrao L. , Amin I. , Briddon R. W. , Malik K. A. , Zafar Y. 
Published: May 2007

Cotton leaf curl is a devastating disease of cotton that has resulted in severe losses (estimated at more than US$87 million per annum) in Pakistan. The epidemic is centered in Punjab, the province that contributes approximately 80% of Pakistan's cotton. Previously, the disease had been observed sporadically on single plants in the northern Sindh Province but did not cause economically significant damage. During the years 2004 and 2005, a high incidence (approximately 20%) of the disease was observed in Shahdadpur and parts of District Sanghar, located in central Sindh Province. The disease was also observed at low incidence (<1%) in southern Sindh. To confirm the identity of the causal agent of the disease, 18 samples from three districts in central southern Sindh (Sanghar, Hala, and Hyderabad) were collected, and total DNA was extracted using cetyltrimethylammoniumbromide (2). Universal primers for begomoviruses based on conserved sequences as follows were used in polymerase chain reaction (PCR): BegomoF (5′-CCGTGCTGCTGCCCCCATTGTCCGCGTCAC-3′) and BegomoR (5′-CTGCCACAACCATGGATTCACGCACAGGG-3′). Universal primers for amplification of DNA β with PCR were also used (1). A full-length clone of Cotton leaf curl Multan virus (CLCuMV) was labeled with alpha-32PdCTP by the oligo-labeling method and used as a probe in Southern hybridization for the detection of geminivirus DNA forms (2). Similarly, cotton leaf curl disease associated DNA β was also labeled and used as a probe in Southern hybridization. The use of universal primers for begomoviruses resulted in amplification of viral DNA of the expected size from all samples while no PCR product was obtained from healthy plants. PCR results confirmed that all plants were infected with begomoviruses. Southern hybridization with CLCuMV and DNA β probes detected begomovirus DNA forms associated with virus replication when washed at medium stringency, further confirming that the plants were infected with the cotton leaf curl geminivirus complex (2). Our results indicate that cotton leaf curl complex has become established in central and southern districts of Sindh Province and it poses a major threat to cotton grown in the region. References: (1) R. W. Briddon et al. Mol. Biotechnol. 20:315, 2002. (2). S. Mansoor et al. Arch. Virol. 148:1969, 2003.
First Report of a Begomovirus Infecting Sweetpotato in Kenya
Authors: Miano D. W. , LaBonte D. R. , Clark C. A. , Valverde R. A. , Hoy M. W. , Hurtt S. , Li R. 
Published: May 2007

Previous surveys for viruses in sweetpotatoes (Ipomoea batatas) in Africa did not assay for the presence of begomoviruses such as Sweet potato leaf curl virus (SPLCV), which have been found recently in the Americas and Asia. Symptomatic sweetpotato plants, including some with leaf curling symptoms similar to those observed in SPLCV-infected sweet-potato plants (2), were collected from a germplasm collection plot at Kakamega Research Station in Western Kenya during February 2005. Whiteflies, the vectors for begomoviruses, were observed in the same plots. Ipomoea setosa plants graft-inoculated with scions from the symptomatic sweetpotato developed leaf curl, leaf roll, interveinal chlorosis, and stunting symptoms similar to those caused by infection with SPLCV alone or in combination with Sweet potato feathery mottle virus. Total DNA was isolated from 10 I. setosa plants using the GenElute Plant Genomic DNA Kit (Sigma-Aldrich Inc., St. Louis, MO). Sweetpotato cuttings from 39 clones, selected from the Kenyan germplasm collection for their resistance or susceptibility to sweetpotato virus disease (SPVD), were sent to the Plant Germplasm Quarantine Office of USDA-ARS. The cuttings were planted in a greenhouse. Total DNA was extracted from sweetpotato leaves 1 month later using a cetyltrimethylammoniumbromide (CTAB) extraction method (1). Degenerate primers SPG1/SPG2, developed for PCR detection of begomoviruses (1), amplified a 912-bp DNA fragment from 3 of 10 DNA extracts from I. setosa and 5 of 39 sweetpotato plants held in quarantine. The primers anneal to regions of open reading frame (ORF) AC2 and ORF AC1 that are highly conserved in begomoviruses infecting sweetpotato. SPLCV-specific primers PW285-1/PW285-2 (2) amplified a 512-bp DNA fragment of ORF AC1 from seven samples (two from I. setosa and five from I. batatas). Amplicons from three independent PCR assays of two samples and single PCR assays of four additional samples were cloned into the pGEM-T Easy vector. Clone inserts were sequenced, and compared with sequences deposited in GenBank using the basic local alignment search tool (BLAST). Sequences were closely related to SPLCV (GenBank Accession No. AF104036) with nucleotide sequence identities varying from 93% (GenBank Accession No. DQ361004) to 97% (GenBank Accession No. DQ361005). The presence of the virus poses a challenge to the dissemination of planting materials in the region because begomovirus-infected plants often do not show symptoms. To our knowledge, this is the first report of a begomovirus infecting sweetpotato in Kenya or the East African Region. References: (1) R. Li et al. Plant Dis. 88:1347, 2004. (2) P. Lotrakul et al. Plant Dis. 82:1253, 1998.
First Report of Soybean Rust Caused by Phakopsora pachyrhizi on Kudzu (Pueraria montana var. lobata) in Kentucky
Authors: Hershman D. E. , Bachi P. R. , Harmon C. L. , Harmon P. F. , Palm M. E. , McKemy J. M. , Zeller K. A. , Levy L. 
Published: May 2007

Phakopsora pachyrhizi, the causal organism of soybean rust, was first observed in the continental United States on 6 November 2004 (2). On 11 November 2005, as part a national soybean rust monitoring effort, 75 leaves of kudzu (Pueraria montana var. lobata) were arbitrarily collected from a patch growing in Princeton, Caldwell County, Kentucky (37.106650°N, 87.886120°W) that had been periodically scouted for the presence of the disease since May 2005. Upon microscopic examination of the nonincubated sample, a small (˜2.0 cm2) area of one leaf exhibited lesions, uredinia, and urediniospores characteristic of those reported for P. pachyrhizi (the Asian species) and P. meibomiae (the New World species) (2). No other infected leaves were observed despite repeated visits to the site and collection and observation of nearly 200 leaves. On 16 November 2005, one-half of the symptomatic tissue was sent by overnight courier to the USDA/APHIS/PPQ/NIS Laboratory, Beltsville, MD and the other half was sent to the Southern Plant Diagnostic Network Laboratory (SPDN), University of Florida, Gainesville. Both laboratories confirmed that the rust was a Phakopsora spp. on the basis of morphological examination. The preliminary polymerase chain reaction (PCR) testing conducted by the SPDN according to Harmon et al. (1) indicated the presence of P. pachyrhizi that was confirmed by the USDA/NPGBL using the validated modified real-time PCR assay described previously (2). The field diagnosis of P. pachyrhizi and preliminary PCR results were officially confirmed by USDA/APHIS on 18 November 2005. To our knowledge, this is the first report of P. pachyrhizi on kudzu or any host in Kentucky, and currently, the northernmost report of soybean rust on any host in the continental United States. References: (1) P. F. Harmon et al. On-line publication, doi:10.1094/PHP-2005-0613-O1-RS. Plant Health Progress, 2005. (2) R. W. Schneider et al. Plant Dis. 89:774, 2005.
First Report of Meloidogyne arenaria Parasitizing Lettuce in Southern Spain
Authors: Castillo P. , Landa B. B. , Navas-Cortés J. A. , Vovlas N. , Jiménez-Díaz R. M. 
Published: May 2007

During the 2005-2006 autumn to winter lettuce-growing (Lactuca sativa cv. Iceberg) season, severely stunted and yellowing lettuce plants with disease incidence ranging from 80 to100% were observed in four commercial, fall-sown fields at Almodóvar del Río (Córdoba Province) in southern Spain. Early symptoms consisted of severely reduced growth of the plants that continued with extensive leaf yellowing and the absence of tight-head formation. Attacks by the disease were estimated to cause near complete loss of the crop yields since the lettuce head produced in affected fields were unmarketable. Observations of affected lettuce plants revealed high parasitism of the root system by a root-knot nematode (Meloidogyne sp.) in the main and feeder roots as well as heavy soil infestations by the nematode. The nematode was identified by the female perineal pattern, esterases phenotype, and a sequence-characterized amplified region polymerase chain reaction (SCAR-PCR) technique (1,2,4). Measurements and morphological observations of 20 second-stage juveniles (J2s) (body length = 463 ± 28 μm, dorsal gland orifice from stylet base = 2.8 ± 0.6 μm, stylet length = 10.4 ± 0.5 μm, tail length = 54.4 ± 0.6 μm; hyaline tail terminus = 9.4 ± 0.6 μm) and 10 adult females (stylet length = 14.5 ± 0.7 μm, dorsal gland orifice from stylet base = 4.7 ± 0.5 μm, and perineal pattern with low and rounded dorsal arch with coarse striae) conformed to the description of Meloidogyne arenaria (3). On the basis of the characteristics of the perineal pattern, the 2-band esterase phenotype, and the 420-bp SCAR fragment, the causal agent was identified as the peanut root-knot nematode M. arenaria. Nematodes were extracted from soil and root samples by standard procedures and their populations quantified. M. arenaria was detected in nearly all soil and root samples assessed, with nematode population densities ranging from 206 to 1,072 eggs and J2s per 5 g of fresh roots. Different Meloidogyne spp. have been reported parasitizing lettuce roots, especially M. hapla in northern areas (2); however, to our knowledge this is the first time that M. arenaria is reported parasitizing lettuce roots in Spain and elsewhere. References: (1) P. R. Esbenshade and A. C. Triantaphyllou. J. Nematol. 22:10, 1990. (2) N. A. Mitkowski et al. Plant Dis. 86:840, 2002. (3) K. J. Orton Williams. Meloidogyne arenaria. CIH Descriptions of Plant-Parasitic Nematodes. Set 5, No. 62. Commonwealth Institute of Helminthology, St. Albans, 1975. (4) C. Zijlstra et al. Nematology 2:847, 2000.