bluuebunny/crossref_metadata_2025_split huggingface dataset:
Natural Infection of Canavalia ensiformis with Tobacco mosaic virus in Venezuela
Authors: Marys E. , Ortega E. , Carballo O. , Ramis C. 
Published: May 2007

Jack bean (Canavalia ensiformis) is a valuable green manure and cover-crop species. In late summer of 2002, jack bean plants showing severe stunting, leaf mosaic, mottling, distortion, and general yellowing were observed in fields located in Maracay, Aragua State, Venezuela. Sap from symptomatic leaves was used to mechanically inoculate healthy jack bean, and field symptoms were successfully reproduced. Similar inoculations on Nicotiana tabacum var. Sansum resulted in mosaic symptoms and leaf distortion. Electron microscopic examination of leafdip preparations showed filamentous rods resembling those of a tobamovirus. Tobacco mosaic virus (TMV) was specifically identified with TMV-specific polyclonal antibody (PVAS-958, ATTC) in enzyme-linked immunosorbent assay. Sequence analysis of a coat protein gene (CP) fragment amplified using reverse transcription-polymerase chain reaction (RT-PCR) with primers TMV-CP-F and TMV-CP-R (1) from total RNA confirmed the diagnosis. Nucleotide and deduced amino acid sequences of a 450-bp region of the RT-PCR product were 96 to 99% and 98 to 100% identical, respectively, to the TMV CP gene in GenBank Accession Nos. J02415 and X68110. On the basis of foliar symptoms, incidence of TMV in jack bean was more than 50% in this experimental field. The source of infection is not known. Because TMV is reported to be seedborne in many other plant species, testing jack bean seed stocks for TMV infection could have important implications on the future control of the virus. To our knowledge, this is the first report of natural infection of jack bean by a tobamovirus. Reference: (1) N. J. Spence et al. Eur. J. Plant Pathol. 107:633, 2001.
First Report of Powdery Mildew (Oidium sp.) on Akebia quinata in Italy
Authors: Garibaldi A. , Bertetti D. , Gullino M. L. 
Published: May 2007

Akebia quinata Decne., an ornamental species belonging to the family Lardizabalaceae, is used as a climbing species in gardens to cover walls as well as supports and is very much appreciated because of its dark red flowers. During the summer of 2003, severe outbreaks of a previously unknown powdery mildew were observed on established plantings in several gardens near Biella (northern Italy). The upper surfaces of leaves were covered with white mycelium, and the corresponding abaxial surface of infected leaves were chlorotic. Young, green stems also affected showed extended chlorosis. As the disease progressed, infected leaves turned yellow and died. Foot cell was cylindric and appressorium lobed. Conidia formed singly were hyaline, ellipsoid, and measured 26.4 to 45.6 × 10.6 to 15.6 μm (average 35.1 × 12.7 μm). Fibrosin bodies were not present. The pathogen was identified as Oidium sp. subgenus Pseudoidium (1) partially because cleistothecia were not observed. Conidial measurements are close to those reported for Microsphaera akebiae Sawada. Pathogenicity was confirmed by gently pressing diseased leaves onto leaves of healthy A. quinata plants. Three plants of A. quinata were used as replicates. Noninoculated plants served as controls. Plants were maintained between 20 and 30°C in a garden located 5 km from where the disease was originally found. After 10 days, typical symptoms of powdery mildew developed on inoculated plants. Noninoculated plants did not show symptoms. To our knowledge, this is the first report of the presence of powdery mildew on A. quinata in Italy. The disease is currently restricted to the area of Biella. The presence of M. akebiae was recently reported in the Netherlands (2). Specimens of this disease are available at the DIVAPRA Collection at the University of Torino. References: (1) U. Braun and S. Takamatsu. Schlechtendalia, 4:1, 2000. (2) M. Scholler and W. Gams. Nova Hedwigia, 67:101, 1998.
First Report of Shining Willow as a Host Plant for Septoria musiva
Authors: Feau N. , Bernier L. 
Published: May 2007

During the summer of 2001, leaf spots resembling those caused by Septoria musiva Peck. were observed on shining willow (Salix lucida Mühl. subsp. lucida) at Leclerville, Québec, Canada (46°34′19″N,71°59′35″W). Affected leaves had brown, necrotic leaf spots (>5mm in diameter) surrounded by a darker brown halo. Conidia were cylindrical, straight to curved with 1 to 4 septa, 28 to 54 × 3.5 to 4 μm, and were produced in pycnidia located on the abaxial surface in the center of the leaf spots. The causal agent of this disease was successfully isolated by germinating the conidia on corn meal agar that was supplemented with streptomycin (50mg/ml) and chloramphenicol (300mg/ml) and followed with the transfer of the germinated conidia to potato dextrose agar. Leaf symptoms and morphology matched those of S. musiva, the cause of leaf spot and stem canker of hybrid poplars in North America (2,4). The internal transcribed spacers and the 5.8S portion of the rDNA were amplified using PCR with the ITS1 (5′-TCC GTA GGT GAA CCT GCG G-3′) and ITS2 (5′-GCT GCG TTC TTC ATC GAT GC-3′) primer pair on total genomic DNA extracted from a pure culture of the pathogen. The rDNA sequence obtained (GenBank Accession No. AY555277) had 100% identity at 506 base positions with the ITS1, 5.8S, and ITS2 of three S. musiva isolates from Québec and one from Wisconsin (GenBank Accession Nos. AY549464 to AY549467). To test for pathogenicity, excised leaf disks from plants propagated by softwood cuttings of the source plant and from one hybrid poplar clone (Populus maximowiczii × P. xjackii) were inoculated with 3 μl of a suspension of ground mycelium or sterile water (control). Disks were placed in a 24-well tissue culture plate with 1 ml of distilled water per well and incubated in a growth room maintained at 22°C with a 16-h photoperiod. After 1 month, symptoms were similar to those previously observed. Isolates collected from shining willow or hybrid poplar were able to induce S. musiva leaf spot symptoms on leaf disks excised from shining willow or the hybrid poplar clone. From symptomatic leaf disks, S. musiva was consistently reisolated. To our knowledge, this is the first report of S. musiva on a member of the genus Salix. S. didyma, S. salicicola, and S. salicina have been reported from leaves of species of Salix (1,3). Only a vague morphological description of S. didyma was found (3). Moreover, conidia of S. salicicola (20 to 50 × 2.5 to 3.5 μm) and S. salicina (40 to 60 μm long, unspecified width) overlap dimensions of S. musiva conidia (1). There is a need to reexamine the relationships between these species of Septoria. Evidently, the complete host range of S. musiva is not yet known. References: (1) L. Lanier et al. Mycologie et Pathologie Forestières. Masson. Paris, 1978. (2) M. E. Ostry. Eur. J. For. Pathol. 17:158, 1987. (3) P. A. Saccardo. Sylloge fungurum omnium hucusque cognitorum. Patavii: Sumptibus Auctoris, 1882. (4) L. J. Spielman et al. Plant Dis. 70:968, 1986.
First Report of Black Sigatoka of Banana Caused by Mycosphaerella fijiensis on Grand Bahama Island
Authors: Ploetz R. C. 
Published: May 2007

Black Sigatoka, which is also known as black leaf streak, is caused by Mycosphaerella fijiensis (anamorph Pseudocercospora [formerly Paracercospora) fijiensis]). It is the most important disease of commercially produced banana (Musa spp.) and also has a major impact on production for local consumption. Although the disease occurs throughout the humid tropics, it has been reported in the Caribbean from only Cuba, Hispaniola, and Jamaica (1). In February 2004, black Sigatoka was observed at two isolated and widely separated sites on Grand Bahama island (26.7°N, 78.5°W and 26.7°N, 78°W) on cvs. Silk AAB and Williams AAA, and a French Horn AAB plantain. Symptoms included wet, dark brown streaks on the adaxial leaf surface, 1 to 2 × 10 mm, with chlorotic haloes. Lesions enlarged to 5 × 20 mm and developed tan, necrotic centers; large, blackened, water-soaked areas that resulted from the coalescence of streaks were rare. The disease was confirmed by observing the following characteristics of P. fijiensis in necrotic lesions on preserved leaf specimens: simple conidiophores with a broadened base and one to several septa, straight to variously bent cercosporoid conidia as much as 100 μm long with two to several septa, and a conspicuously thickened scar at the base. Both plantings were several years old and new planting material that could have been infested with the pathogen had not been introduced since their establishment. Symptoms were not severe and were distributed sporadically in both locations. The disease was not observed at the only other large planting of banana on the island (26.6°N, 78.6°W). The sporadic and apparently new infestations of two of three banana plantings on the island suggest that the pathogen may have arrived recently via natural means, possibly from neighboring Florida (2). In contrast, black Sigatoka appears to have spread to other islands in the Caribbean via infested propagation materials (1). To my knowledge, this is the first report of black Sigatoka in the Bahamas, and with a previous report from Bhutan (1), represents the northernmost spread of this important disease. References: (1) J. Carlier et al. Pages 37–79 in: Diseases of Banana, Abacá and Enset. D. R. Jones, ed. CABI Publishing. Wallingford, UK, 2000. (2) R. C. Ploetz and X. Mourichon. Plant Dis. 83:300, 1999.
Seed Transmission of Citrus leaf botch virus: Implications in Quarantine and Certification Programs
Authors: Guerri J. , Pina J. A. , Vives M. C. , Navarro L. , Moreno P. 
Published: May 2007

Citrus leaf blotch virus (CLBV) was purified and characterized from a Nagami kumquat (Fortunella margarita (Lour.) Swingle), showing bud union crease when propagated on Troyer citrange (Citrus sinensis (L.) Osbeck × Poncirus trifoliata (L.) Raf.) (2). The complete nucleotide sequence of its genomic RNA was determined (4), and biological and molecular diagnosis methods were developed (1,3). CLBV, detected in several citrus cultivars from Australia, the United States (Florida and California), Japan, and Spain is usually associated with bud union crease on citrange or citumelo (C. paradisi (Macfad.) × P. trifoliata). The economic importance of CLBV for the citrus industry is presently unknown since its incidence in different citrus areas has not been evaluated, and its actual involvement in causing bud union crease on trifoliate rootstocks has not yet been proved. To assess seed transmissibility of this virus, 120 to 210 seeds from CLBV-infected Troyer citrange, Nagami kumquat, or sour orange (Citrus aurantium L.) plants were grown in a greenhouse. Individual 4-month-old seedlings were analyzed for CLBV by reverse transcriptase polymerase chain reaction, and infection was confirmed by biological indexing on Dweet tangor (C. tangerina Hort. ex Tanaka × C. sinensis (L.) Osbeck) when seedlings were approximately 18 months old. Seed transmission was found in 2.50, 2.52, and 2.46% of the citrange, kumquat, and sour orange seedlings, respectively. This finding indicates that control of CLBV spread during citrus propagation will require, not only virus-free buds, but also rootstock seedlings that originate from CLBV-free seed source trees. Because CLBV is seed transmissible, regulations of citrus certification programs may need to be changed to include increased control of seed source trees. Also, international regulations for citrus seed movement likely will have to be augmented to include a phytosanitary certification indicating that seeds have been collected from CLBV-free trees. References: (1) L. Galipienso et al. Plant Pathol. 49:308, 2000. (2) L. Galipienso et al. Arch. Virol. 146:357, 2001. (3) L. Galipienso et al. Eur. J. Plant Pathol. 110:175,2004. (4) M. C. Vives et al. Virology 287:225, 2001.
New Natural Hosts of Pepino mosaic virus in Spain
Authors: Córdoba M. C. , Martínez-Priego Ll. , Jordá C. 
Published: May 2007

Pepino mosaic virus (PepMV) was first detected in Spain in 2000 (1). The virus infects tomato (Lycopersicon esculentum Mill.) crops and causes a variety of symptoms including leaf distortion, chlorosis, mosaic, blistering of the leaf surface, green striations on the stem and sepals, and fruit discoloration. PepMV is present along the southern and eastern regions of Spain (provinces of Granada, Almeria, Murcia, Alicante, Valencia, and Barcelona), Balearic, and the Canary Islands. In the summer and autumn of 2001 and 2002, virus-like symptoms were observed in native plants growing in or around tomato fields in Murcia and Almeria provinces. To study the alternate hosts that may serve as virus reservoirs, 62 samples of 42 common weed species, including asymptomatic plants, were collected and analyzed for PepMV using double-antibody sandwich enzyme-linked immunosorbent assay with a commercial antiserum (DSMZ As-0554; Biologische Bundesantstal, Braunschweig, Germany). The following weed hosts tested positive for PepMV: Bassia scoparia (L.) Voss., Calystegia sepium (L.) R.Br., Chenopodium murale L., Convolvulus althaeoides L., Convolvulus arvensis L., Conyza albida Willd. ex Spreng., Coronopus sp., Diplotaxis erucoides (L.) DC, Echium creticum L., E. humile Desf., Heliotropium europaeum L., Moricandia arvensis (L.) DC., Onopordum sp., Piptatherum multiflorum (Cav.) Beauv., Plantago afra L., Rumex sp., Sisymbrium irio L., Sonchus tenerrimus L., and Taraxacum vulgare (Lam.) Schrank. The presence of PepMV in these weed species was confirmed using reverse transcription-polymerase chain reaction with primers specific for PepMV (2). Although the number of samples examined may be insufficient to assess precisely the role of weed reservoirs in outbreaks of PepMV, these findings reveal potential virus sources and contribute to further understanding of PepMV epidemiology in Spain. References: (1) C. Jordá et al. Plant Dis. 85:1292, 2001. (2) P. Martínez-Culebras et al. Eur. J. Plant Pathol. 108:887, 2002.
First Report of Cucurbit aphid-borne yellows virus in Spain
Authors: Juarez M. , Truniger V. , Aranda M. A. 
Published: May 2007

In late spring 2003, field-grown melon plants (Cucumis melo L.) showing bright yellowing of older leaves were observed near Valladolises in Campo de Cartagena, Murcia, Spain. Symptoms resembled those caused by viruses of the genus Crinivirus (family Closteroviridae), but absence or very low populations of whiteflies were observed. However, diseased foci showed clear indications of heavy aphid infestations. Later, during the fall of 2003, squash plants (Cucurbita pepo L.) grown in open fields in the same area showed similar symptoms. Tissue print hybridizations to detect Cucurbit yellow stunting disorder virus (CYSDV) and Beet pseudo yellows virus (BPYV) in symptomatic samples were negative. CYSDV and BPYV are two yellowing-inducing criniviruses previously described in Spain. In contrast, standard double-antibody sandwich enzyme-linked immunosorbent assays (DAS-ELISA) with antiserum against Cucurbit aphid-borne yellows virus (CABYV; genus Polerovirus, family Luteoviridae) that was kindly provided by H. Lecoq (INRA-Montfavet Cedex, France) were consistently positive. Definitive confirmation of CABYV associated with symptomatic samples was obtained by performing reverse-transcription polymerase chain reaction (RT-PCR) analyses for the CABYV coat protein gene. Total RNA extracts (TRI reagent; Sigma Chemical, St. Louis, MO) were obtained from symptomatic and asymptomatic leaf samples and RT-PCR reactions were carried out using the primers 5′-GAATACGGTCGCGGCTAGAAATC-3′ (CE9) and 5′-CTATTTCGGGTTCTGGACCTGGC-3′ (CE10) based on the CABYV sequence published by Guilley et al. (2). A single DNA product of approximately 600 bp was obtained only from symptomatic samples. Amplified DNA fragments from two independent samples (samples 36-2 and 37-5) were cloned in E. coli and sequenced (GenBank Accession Nos. AY529653 and AY529654). Sequence comparisons showed a 95% nucleotide sequence identity between the two sequences. A 97% and 94% nucleotide sequence identity was found among 36-2 and 37-5, respectively and the CABYV sequence published by Guilley et al. (2). CABYV seems to be widespread throughout the Mediterranean Basin (1,3) but to our knowledge, it has not previously been described in Spain. Additionally, our data suggest that significant genetic variability might be present in the Spanish CABYV populations. References: (1) Y. Abou-Jawdah et al. Crop Prot. 19:217, 2000. (2) H. Guilley et al. Virology 202:1012, 1994. (3) H. Lecoq et al. Plant Pathol. 41:749, 1992.
First Report of Downy Mildew Caused by Plasmopara obducens on Impatiens in California
Authors: Wegulo S. N. , Koike S. T. , Vilchez M. , Santos P. 
Published: May 2007

During February 2004, diseased double impatiens (Impatiens walleriana) plants were received from a commercial grower in southern California. The upper surfaces of symptomatic leaves were pale yellow with no distinct lesions. Diseased leaves later wilted, and severely affected leaves abscised from the stem. At the nursery, only double impatiens plants in the Fiesta series were infected, and some cultivars were more heavily infected than others. Disease incidence in cv. Sparkler Hot pink was nearly 100%. The interior of infected leaves was colonized by coenocytic mycelium. A conspicuous white growth was observed only on the underside of leaves. Sporangiophores were hyaline, thin walled, emergent from stomata, and had slightly swollen bases. Sporangiophore branching was distinctly monopodial. Smaller sporangiophore branches were arranged at right angles to the supporting branches, and tips of branches measured 8 to 14 μm long. Sporangia were ovoid and hyaline with a single pore on the distal ends. Distal ends of sporangia were predominantly flat but occasionally had a slight papilla. Short pedicels were present on the attached ends. Sporangia measured 19.4 to 22.2 (-25.0) μm × 13.9 to 16.7 (-19.4) μm. Oospores were not observed in leaf tissue. On the basis of symptoms and morphology of the organism, the pathogen was identified as Plasmopara obducens J. Schröt. Pathogenicity tests were done on double type cvs. Fiesta, Tioga Red, and Tioga Cherry Red and on single type cvs. Cajun Watermelon and Accent Lilac. Plants were spray inoculated with sporangiospore suspensions (1 × 104 sporangiospores per milliliter), incubated for 24 h in a dew chamber (18 to 20°C), and then maintained in a greenhouse (22 to 24°C). Symptoms and signs of downy mildew developed after 12 days only on inoculated cv. Fiesta plants, and the pathogen morphology matched that of the originally observed pathogen. Nontreated control plants did not develop downy mildew. To our knowledge, this is the first report of downy mildew on impatiens in California. P. obducens is one of two causal agents of downy mildew of impatiens (2,4). The other pathogen, Bremiella sphaerosperma, has dichotomous sporangiophore branching and causes lesions with well-defined margins (2,4). In the United States, the disease has been recorded in the eastern and northeastern states and in Indiana, Minnesota, Mississippi, Montana, and Wisconsin (3). In Canada, the disease has been recorded in Manitoba and Quebec (1). References: (1) I. L. Conners. An Annotated Index of Plant Diseases in Canada and Fungi Recorded on Plants in Alaska, Canada, and Greenland. Research Branch, Canada Department of Agriculture, Publication 1251, 1967. (2) O. Constantinescu. Mycologia 83:473, 1991. (3) D. F. Farr et al. Fungi on Plants and Plant Products in the United States. The American Phytopathological Society, 1989. (4) G. W. Wilson. Bull. Torrey Bot. Club 34:387, 1907.
First Report of Cherry virus A and Little cherry virus-1 in Poland
Authors: Komorowska B. , Cieślińska M. 
Published: May 2007

Cherry virus A (CVA), a member of the genus Capillovirus, has been reported in sweet cherry in Germany, Canada, and Great Britain. No data are available on the effects of CVA on fruit quality and yield of infected trees. Little cherry disease (LChD) occurs in most cherry growing areas of the world. Symptoms on sensitive cultivars include discolored fruit that remain small, pointed in shape, and tasteless. Three Closterovirus spp. associated with LChD have been described (Little cherry virus-1 [LChV-1], LChV-2, and LChV-3). Diseased local and commercial cultivars of sour cherry trees were found in a Prunus sp. germplasm collection and orchards in Poland during the 2003 growing season. The foliar symptoms included irregular, chlorotic mottling, distortion, and premature falling of leaves. Some of the diseased trees developed rosette as a result of decreased growth and shortened internodes. Severely infected branches exhibited dieback symptoms. Because the symptoms were suggestive of a possible virus infection, leaf samples were collected from 38 trees and assayed for Prune dwarf virus and Prunus necrotic ringspot virus using double antibody sandwich enzyme-linked immunosorbent assay (DAS-ELISA). RNA extracted from leaves was used in a reverse transcription-polymerase chain reaction (RT-PCR) with the One-Step RT-PCR with Platinum Taq (Invitrogen Life Technologies) and primer sets specific for CVA (1), LChV-1 (3), and LChV-2 (3). The RNA samples were also tested using RT-PCR for detection of Cherry mottle leaf virus (CMLV), Cherry necrotic rusty mottle virus (CNRMV), and Cherry green ring mottle virus (CGRMV) with specific primer sets (2). Amplification of a 397-bp coat protein gene product confirmed infection of 15 trees with CVA. A 419-bp fragment corresponding to the coat protein gene of LChV-1 was amplified from cv. Gisela rootstock and local cv. WVIII/1. To confirm RT-PCR results, CVA amplification products from local cv. WX/5 and LChV-1 from cvs. Gisela and WVIII/1 were cloned in bacterial vector pCR 2.1-TOPO and then sequenced. The sequences were analyzed with the Lasergene (DNASTAR, Madison, WI) computer program. The alignment indicated that the nucleotide sequence of cv. WX/5 was closely related to the published sequences of CVA (Genbank Accession No. NC_003689) and had an 89% homology to the corresponding region. The nucleotide sequence similarity between the 419-bp fragment obtained from cvs. Gisela and WVIII/1 was 87% and 91%, respectively, compared with the reference isolate of LChV-1 (Genbank Accession No. NC_001836). The sampled trees tested negative for LChV-2, CGRMV, CMLV, and CNRMV using RT-PCR. Some trees tested positive for PNRSV and PDV. To our knowledge, this is the first report of CVA and LChV-1 in Poland. References: (1) D. James and W. Jelkmann. Acta Hortic. 472:299, 1998. (2) M. E. Rott and W. Jelkmann. Eur. J. Plant Pathol. 107:411,2001. (3) M. E. Rott and W. Jelkmann. Phytopathology. 91:61, 2001.