bluuebunny/crossref_metadata_2025_split huggingface dataset:
First Report of Soybean Rust Caused by Phakopsora pachyrhizi in the Continental United States
Authors: Schneider R. W. , Hollier C. A. , Whitam H. K. , Palm M. E. , McKemy J. M. , Hernández J. R. , Levy L. , DeVries-Paterson R. 
Published: May 2007

Asian soybean rust, caused by Phakopsora pachyrhizi Sydow, has been known to occur in the eastern hemisphere for nearly a century. More recently, it was reported from Hawaii in 1994, eastern and southern Africa from 1996-1998, Nigeria in 2001, and Brazil and Paraguay in 2002. Aerobiological models suggested that urediniospores of the pathogen would be disseminated on wind currents to the continental United States in association with tropical storms if the disease became established north of the equator during hurricane season (U.S. Soybean Rust Detection and Aerobiological Modeling online publication at www.aphis.usda.gov/ppq/ ep/soybean_rust/ ). Since soybean rust was observed at approximately 5°N latitude in South America before several hurricanes impacted the continental United States in September 2004, it seems likely that the introduction was associated with at least one of these tropical storms, especially hurricane Ivan. Symptoms of the disease were first observed on soybean (Glycine max (L.) Merr.) in the continental United States on November 6, 2004 in a field near Baton Rouge, LA. Typical pustules and urediniospores on infected leaves were readily apparent when viewed with a dissecting microscope. Urediniospores were obovoid to broadly ellipsoidal, hyaline to pale yellowish brown with a minutely echinulate thin wall, and measured 18 to 37 × 15 to 24 μm. Paraphyses were cylindric to clavate and slightly thickened at the apex, colorless to pale yellowish brown, and 25–50 × 6–14 μm in size. This morphology is typical of Phakopsora pachyrhizi and P. meibomiae, a less aggressive, western hemisphere species (2). DNA was extracted from leaves containing sori using the Qiagen DNeasy Plant Mini kit. P. pachyrhizi was detected using a real-time polymerase chain reaction (PCR) protocol (1) that differentiates between P. pachyrhizi and P. meibomiae performed in a Cepheid thermocycler with appropriate positive and negative controls. The PCR master mix was modified to include OmniMix beads (Cepheid). The field diagnosis of P. pachyrhizi was confirmed officially by the USDA/APHIS on November 10, 2004, and this was followed on November 11, 2004 by a wide-ranging survey of soybean and kudzu (Pueraria sp.) in soybean production areas in southern and central Louisiana. Collections from this survey also were assayed as described above, and six soybean specimens from five sites were confirmed positive. The disease was not found on kudzu samples. To our knowledge, this is the first report of P. pachyrhizi in the continental United States. Voucher specimens have been placed in the USDA National Fungus Collection. References: (1) R. D. Frederick et al. Phytopathology 92:217, 2002. (2) Y. Ono et al. Mycol. Res. 96:825, 1992.
First Report of Pear Decline Phytoplasmas on Pear in Serbia
Authors: Duduk B. , Ivanović M. , Obradović A. , Paltrinieri S. , Bertaccini A. 
Published: May 2007

During August of 2004, pear (Pyrus communis L.) plants with typical symptoms of pear decline (PD) were observed in orchards in central Serbia. The affected plants showed premature reddening and upward rolling of leaves that often showed down-turned petioles. In some cases, premature defoliation was observed. Although a similar decline of pear was observed earlier, until now, the causal agent had not been identified. DNA was extracted with a chloroform/phenol procedure from fresh leaf midribs and branch phloem scrapes of four symptomatic and one asymptomatic pear plants separately. A nested polymerase chain reaction assay (PCR) was used for phytoplasma detection (first PCR round with P1/P7 (4) phytoplasma universal primer pair, followed by nested PCR with group 16SrX specific primers f01/r01) (3). With these primers, the expected products from phloem scrapes and midrib extracts of symptomatic plant samples were obtained. Restriction fragment length polymorphism (RFLP) analyses of the f01/r01 amplicon, with RsaI and SspI restriction enzymes, discriminating among 16SrX subgroup phytoplasmas, showed profiles corresponding to those of the apple proliferation phytoplasma group, 16SrX-C subgroup, “Candidatus Phytoplasma pyri” (2). A 1,155-bp sequence of 16S rDNA gene for one of the PA2f/r (1) amplicons obtained in nested PCR on P1/P7 products from one of the leaf midrib samples was deposited in GenBank (Accession No. AY949984); both strands of the fragment were sequenced with the Big Dye Terminator reaction kit (Applied Biosystems, Foster City, CA). The sequences were analyzed with the Chromas 1.55 DNA sequencing software (Technelysium, Queensland, Australia) and aligned with BLAST software ( http://www.ncbi.nlm.nih.gov ). The blast search showed 100% homology of this sequence with that of PD strain Y16392, confirming the identity with PD of the phytoplasma detected. To our knowledge, this is the first report of pear decline phytoplasmas in Serbia. References: (1) M. Heinrich et al. Plant Mol. Biol. Rep. 19:169, 2001. (2) IRPCM Phytoplasma/Spiroplasma Working Team-Phytoplasma Taxonomy Group. Int. J. Syst. Evol. Microbiol. 54:1243, 2004. (3) K.-H. Lorenz et al. Phytopathology 85:771, 1995. (4) Schneider et al. Pages 369–380 in: Molecular and Diagnostic Procedures in Mycoplasmology. Vol I. S. Razin and J. G. Tully, eds. The American Phytopathological Society, 1995.
Transmissibility of Citrus leprosis virus by Brevipalpus phoenicis to Solanum violaefolium
Authors: Rodrigues J. C. V. , Locali E. C. , Freitas-Astua J. , Kitajima E. W. 
Published: May 2007

Citrus leprosis virus (CiLV) constitutes one of the most important viruses in citrus in the areas where it occurs. Two morphological types of virus particles have been described from associated leprosis symptoms, nuclear (CiLV-N) and cytoplasmic (CiLV-C) (4). The CiLV-C is more common, representing more than 99% of samples collected from South and Central America (E. W. Kitajima and J. C. V. Rodrigues, unpublished). Both virus types are associated with the mite vector, Brevipalpus phoenicis (Geijskes) (Acari: Tenuipalpidae). So far, CiLV-C has only been naturally transmitted by these mites to citrus (3). Plants of Solanum violaefolium Schott (Solanaceae) and ornamental and sweet orange seedlings were infested with viruliferous adult female mites, colony no. 61 (GenBank Accession No. AY320027) that were previously maintained on citrus seedlings infected with CiLV-C according to Rodrigues et al. (3). Fifteen days after the mites were transferred, spotted yellowish symptoms were observed on leaves of plants of S. violaefolium and similar symptoms were observed after 25 days on citrus leaves. The symptomatic tissues were studied using transmission electron microscopy. Particles typical of CiLV-C were observed in samples from both plant species. To our knowledge, this is the first reported case of mites transmitting CiLV-C to a noncitrus host. Subsequent experiments showed that mites were able to transmit the virus between plants of S. violaefolium. Attempts to transmit the virus by mites from S. violaefolium to citrus were unsuccessful. The dsRNA viral electrophoresis profile showed differences between the two host plants. Reverse transcription-polymerase chain reaction (RT-PCR) and sequencing assays with primers designed to detect CiLV-C (2) amplified DNA fragments of the expected size and base composition. These data suggest the loss or alteration of some viral components from the Solanum sp. host that might be essential for the transmission or infection in citrus. Such a mechanism may explain why, despite the ever-increasing number of Brevipalpus-transmitted viruses in a large number of different host plant species (1), cross transmission is not common. This information shows one of the potential routes for CiLV to invade citrus orchards, and suggests one alternative host plant that allows rapid multiplication of the virus for characterization. References: (1) E. W. Kitajima et al. Exp. Appl. Acarol. 30:135, 2003. (2) E. C. Locali et al. Plant Dis. 87:1317, 2003. (3) J. C. V. Rodrigues et al. Proc. Int. Org. Citrus Virol. 174, 2000 (4) J. C. V. Rodrigues et al. Exp. Appl. Acarol. 30:161, 2003.
Partial Characterization of a Carla-Like Virus Infecting Yam (Dioscorea spp.) from China
Authors: Lebas B. S. M. , Ochoa-Corona F. M. , Elliott D. R. , Tang Z. , Alexander B. J. R. 
Published: May 2007

Dioscorea opposita (yam) from China was tested for viruses during post-entry quarantine in New Zealand during 2004. No obvious symptoms or virus particles were observed from yam. Mechanically inoculated Nicotiana occidentalis cvs. 37B and P1 produced systemic chlorosis, leaf reduction, and stunting, whereas no symptoms were observed on other tested herbaceous plants (Chenopodium amaranticolor, C. quinoa, Cucumis sativum, Gomphrena globosa, N. benthamiana, N. clevelandii, N. glutinosa, N. sylvestris, and N. tabacum cv. White Burley). Numerous filamentous particles (approximately 600 nm long) were observed by using electron microscopy from symptomatic N. occidentalis. Total RNA was extracted from yam and symptomatic N. occidentalis leaf samples using the Qiagen Plant RNeasy kit (Qiagen, Valencia, CA). Reverse transcription (RT) was carried out using random hexamer primers and SuperScript II RNase H¯ reverse transcriptase (Invitrogen, Carlsbad, CA) followed by polymerase chain reaction (PCR) with different primer pairs. Samples tested negative for Chinese yam necrotic mosaic virus (ChYNMV; genus Macluravirus) with specific primers (supplied by T. Kondo, Aomori Green BioCenter, Aomori, Japan). Negative results were also obtained for the genera Potyvirus, Potexvirus, Capillovirus, Trichovirus, and Foveavirus using RT-PCR with broad detection primers (1,2,4). A positive RT-PCR amplification was obtained from the yam and N. occidentalis samples with universal primers for the genus Carlavirus (Agdia Inc., Elkhart, IN). The 275-bp amplified products from the viral replicase were cloned and sequenced. The yam virus shows a high amino acid similarity with Hop latent virus (87.9%), Aconitum latent virus (86.8%) and Potato virus M (86.8%). Filamentous virus particles belonging to the genera Macluravirus, Potyvirus, and Potexvirus have been reported in yam (3). These virus species are not associated with the carlavirus infection since the virus found in D. opposita tested negative using RT-PCR with primers for these genera. There are no carlaviruses reported to be infecting yams, therefore, it may be considered as a new host-virus association. References: (1) X. Foissac et al. Acta Hortic. 550:37, 2001. (2) S. A. Langeveld et al. J. Gen. Virol. 72:1531, 1991. (3) B. S. M. Lebas. Ph.D. thesis. Greenwich University, Chatham Maritime, UK, 2002. (4) R. A. A. Van der vlugt and M. Berendsen. Eur. J. Plant Pathol. 108:367, 2002.
First Report of Cucumber mosaic virus in Banana from Iran
Authors: Ghotbi T. , Bananej K. 
Published: May 2007

Banana bunchy top virus (BBTV), Banana streak virus (BSV), and Cucumber mosaic virus (CMV) (genus Cucumovirus, family Bromoviridae [2]) cause widespread economic losses on banana (Musa sp.) throughout the world and have been reported on banana in different countries including Pakistan along its southeastern border with Iran (1). A survey was conducted from 2004–2005 to identify viruses infecting banana in greenhouses in different growing areas in northern Iran, Mazandaran Province (Sari, Babol, Behshahr, and Ghaemshahr cities). A total of 180 samples from seven banana-growing greenhouses with symptoms of mosaic, chlorosis, stunting, and fruit malformation were collected. All samples were tested for CMV with polyclonal antibodies using double-antibody sandwich enzyme-linked immunosorbent assay (DAS-ELISA) (CMV strain D subgroup I; gifted by H. Lecoq, INRA, Avignion, France). For sap inoculation onto indicator test plants, selected ELISA-positive leaf samples were ground in chilled 0.01 M phosphate buffer, pH 7.0, containing 0.15% 2-mercaptoethanol. Chlorotic and necrotic local lesions developed on Chenopodium amaranticolor and Vigna unguiculata (cv. Mashad local) 10 and 12 days postinoculation, respectively. Cucumis sativus and Nicotiana rustica also developed systemic mosaic symptoms (3). All indicator test plants were rechecked for the presence of CMV using DAS-ELISA. On the basis of serological tests and indicator host plants reactions, CMV was identified in 32% of samples including Sari (13.8%), Babol (2.7%), Behshahr (10%) and Ghahemshahr (5%), respectively. Fifty-five samples did not react with CMV antiserum but the presence of symptoms resembling BBTV and BSV (4) emphasizes the need for further investigations to confirm the presence and identities of other viruses. References: (1) J. Bird and F. L. Wellman. Phytopathology 52:286, 1962. (2) S. K. Choi et al. J. Virol. Methods 83:67, 1999. (3) A. J. Gibbs and B. D. Harrison. Descriptions of Plant Viruses. No.1. CMI/AAB, Surrey, England, 1970. (4) R. C. Ploetz et al., eds. Compendium of Tropical Fruit Diseases. The American Phytopathological Society, St. Paul, MN, 1994.
First Report of Stem Spots Caused by Alternaria sp. on Berberis sp. in Iran
Authors: Mirabadi S. , Soumi F. , Golnaraghi A. R. , Rezaee S. 
Published: May 2007

During the summer of 2004, approximately 150 Berberis sp. (Berberis thunbergii cv. Rose Glow) showing dark brown, eye-like elongated spots (7 to 22 mm long and 1 to 3 mm wide) on stems near the crown toward the top were observed in a park in Tehran, the capital of Iran. Red and yellow spots on the leaves and defoliation were also recorded for some of the affected plants. A total of 28 samples from 16 individual plants (sampling included all symptomatic parts of the plants) were collected and evaluated for the possible casual agent of the disease. Fungi with spores that are characteristic of the genus Alternaria (2), including dark mycelium and brief and simple conidiophores with catenulate dictyospores, were isolated from the detached leaf and stem pieces of diseased plants. The pathogenicity of five isolates was investigated using Koch's postulate. Twenty cut stems and 10 rooted plants of Berberis sp., with or without wounding on their stems and leaves, were inoculated with the spore suspension (104 spores per ml) prepared by using 10-day-old cultures of the isolates grown on potato dextrose agar at 25°C in the dark. The inoculated cut stems were covered for 3 days with a plastic tent and kept in a greenhouse at 25 ± 5°C with more than 12 h of light. These covers were not used for the rooted plants that were inoculated under field conditions. For each test, at least two controls were used. Symptoms similar to those observed in the field appeared on inoculated stems in 6 to 7 days. On leaves, dark, reddish brown spots (different from the field observations) were induced 3 to 4 days after inoculation. The disease on leaves, which eventually led to defoliation, was more severe than that observed in the field. Stem spots occurred on covered and uncovered inoculated plants; however, the lesions on the covered plants were deeper than those on the uncovered plants. Both types of plants died 3 to 4 weeks after inoculation. Although the fungi were isolated from diseased plants from one park, similar symptoms also were observed on Berberis sp. planted in other parks and streets, etc. The genus Alternaria (Deuteromycetes) caused leaf and stem spot diseases on different plant hosts (1). To our knowledge, this is the first report of a natural occurrence of Alternaria sp. on Berberis sp. in Iran. References: (1) G. N. Agrios. Plant Pathology, 4th ed., Academic Press, NY, 1997. (2) M. B. Ellis. More Dematiaceous Hyphomycetes. Commonwealth Mycological Institute, Kew, England, 1976.
Occurrence of Sclerotinia Stem Rot of Osteospermum sp., Felicia amelloides, and Ranunculus asiaticus in Argentina
Authors: Wright E. R. , Rivera M. C. , Chiesa G. , Morisigue D. 
Published: May 2007

Three ornamental species, Osteospermum sp. (L.), Felicia amelloides (L.) Voss, and Ranunculus asiaticus L., cultivated in greenhouses on the outskirts of Buenos Aires, showed sudden wilt and death during October 2002. These species are new ornamentals in Argentina. The diseased plants were cultivated in plastic containers filled with commercial potting mix. Soft rot was observed at the base of the plants. Stem lesions became covered with whitish mycelium that produced large, black sclerotia (5 to 7 mm in diameter) characteristic of Sclerotinia sclerotiorum (Lib.) de Bary (1). The fungus was consistently recovered from infected stem pieces that were disinfested for 1 min in 0.2% NaOCl and plated on potato dextrose agar (PDA), pH 7. Pathogenicity of the three isolates obtained from infected plants was confirmed by inoculating 10 3-month-old healthy plants of each species in 14-cm-diameter plastic pots. Each isolate was inoculated on the host from which it had been isolated. Inoculum consisted of three mycelial plugs from 7-day-old PDA cultures that were placed on the substrate at the base of the plants. Control plants were treated with sterile agar plugs. Inoculated and noninoculated plants were covered with transparent plastic bags for 2 days and incubated in a growth chamber at 20 to 24°C with a 12-h photoperiod. All inoculated plants developed symptoms of leaf yellowing and wilt. Soft and watery tissues were observed at the base of the plants, soon followed by the appearance of white mycelium. Disease symptoms were similar to those observed on the original infected plants and appeared 6, 5, and 3 days after inoculation on Osteospermum sp., F. amelloides, and R. asiaticus, respectively. All inoculated plants died within 3 weeks, and control plants remained healthy. S. sclerotiorum was reisolated from inoculated plants of each species, fulfilling Koch's postulates. To our knowledge, this is the first report of the occurrence of Sclerotinia stem rot on these three plant species in Argentina. Reference: (1) J. E. M. Mordue and P. Holliday. No. 513 in: Descriptions of Pathogenic Fungi and Bacteria. CMI, Kew, Surrey, UK. 1976.
First Report of the East-Asian Type of Bursaphelenchus mucronatus in Pinus sylvestris in Slovenia
Authors: Urek G. , Širca S. 
Published: May 2007

Bursaphelenchus mucronatus Mamiya & Enda, a nematode associated with aboveground tissues of pine trees, is very similar morphologically to the pine wood nematode (PWN), B. xylophilus, a devastating pest that has caused widespread losses to pine woods in some parts of Asia since the early 1900s. During 1999, B. xylophilus was identified for the first time in Europe in Portugal (3), leading to concern that pines and other conifers all over Europe might be endangered. To protect forests from PWN and other pests, the European Union and other countries now regulate the importation of all coniferous chips, sawn wood, and logs and also have organized surveys to determine the extend of PWN infestation. Slovenia has approximately 1,227,832 ha of forest that makes up more than 60% of the surface of the country. The percentage of conifers within forests is 47.9% and comprised mainly of Picea, Pinus, Abies, and Larix species (2). During the summers of 2002-2004, approximately 100 ha of conifer forests in Slovenia were surveyed for the presence of PWN. In total, 170 wood samples from dead and dying pine (Pinus sylvestris L., P. nigra Arnold), spruce (Picea abies L.), and fir (Abies alba Miller) were analyzed. B. xylophilus (Steiner & Buhrer) Nickle was not found in the area, but a closely related nematode, B. mucronatus, previously shown to be pathogenic on conifer seedlings (4), was isolated from samples of P. sylvestris. Of 34 P. sylvestris samples analyzed, B. mucronatus was found in three samples. Samples were taken from a conifer forest located in the central part of Slovenia near the international airport of Ljubljana. The species was identified morphologically and also characterized by polymerase chain reaction restriction (PCR)-fragment length polymorphism (RFLP) analysis on the basis of ITS-rDNA fragment patterns. According to RFLP patterns (1), the analyzed species was recognized as the East-Asian type of B. mucronatus. Beside these findings, the specimens of B. homanni (Braasch) and Bursaphelenchus sp. have also been found in Slovenia. The results of the survey show that PWN was not found in Slovenia, but three different species of the Bursaphelenchus genus were present. References: (1) H. Braasch et al. Nachrbl. Dtsch. Pflanzenschutzd. 51:312, 1999. (2) M. Jurc et al. Zb. Gozdarstva in Lesarstva 72:121, 2004. (3) M. M. Mota et al. Nematology 1:727, 1999. (4) J. R. Sutherland. Pine wilt nematode. Pages 19–20 in: Compendium of Conifer Diseases. E. M. Hansen and K. J. Lewis, eds. The American Phytopathological Society, St. Paul, MN. 1997.
Biovar of Ralstonia solanacearum Causing Bacterial Wilt of Tomato in Nigeria
Authors: Adebayo O. S. , Ekpo E. J. A. 
Published: May 2007

A survey of southwestern Nigeria showed an outbreak of wilt disease caused by Ralstonia solanacearum in 80% of tomato (Lycopersicon lycopersicum) fields in the production area of Ogun State (7°15′N, 3°25′E) in June 1996. Subsequent surveys conducted in Edo (6°45′N, 5°30′E), Delta (5°15′N, 5°45′E), Lagos (6°30′N, 3°40′E), Oyo (8°40′N, 3°30′E), and Osun (7°50′N, 4°E) states between May and November 1998 identified 60 to 80% infected fields per state. Observations made at the experimental plots of the National Horticultural Research Institute (NIHORT) at Ibadan (7°23′N, 2°50′E) also showed similar infections. Affected plants exhibited initial wilting of terminal leaves followed (within 2 days) by sudden and permanent wilt. For further identification of the causal organism, 10 tomato plants showing wilt symptoms were collected from each of five fields in the vegetable blocks of the NIHORT at Ibadan and 20 farmers' fields in Ogun State. The 10 plants per field were thereafter bulked as one composite sample. Creamy bacterial sap from these samples was plated on tetrazolium chloride media, and plates were incubated at 30°C for 48 h (2). Colonies that were fluidal and white with pink centers were used for biovar determination. Basal media was prepared to include one of three disaccharides (cellobiose, lactose, or maltose) or three hexose alcohols (dulcitol, mannitol, or sorbitol). A loopful of bacterial cells of all 25 isolates was inoculated individually to each of the six media. Cultures were incubated at 30°C for 28 days and monitored daily for color changes. The pathogenicity of the 25 isolates was tested using 10 4-week-old seedlings each of eggplant cv. black beauty, tomato cv. Ibadan local, sweet pepper cv. California wonder, and potato cv. Kufri. Each inoculum was prepared by adjusting the concentration to 107 CFU/ml with a colorimeter at a wavelength of 600 nm (optical density of approximately 0.3). Plants were inoculated by pouring 10 ml of inoculum around the base of each plant. Ten uninoculated seedlings of each cultivar served as the control. Plants were assessed for wilt severity 30 days after inoculation. All isolates utilized the three disaccharides and three hexose alcohols, and according to Hayward's classification, all isolates were biovar 3 (1). Furthermore, the isolates caused rapid wilting of all four test plants. R. solanacearum was easily reisolated from the vascular bundles of the test plants. To our knowledge, this is the first report of this biovar of R. solanacearum affecting tomato crops in Nigeria. References: (1) A. C. Hayward. J. Appl. Bacteriol, 27:265, 1964 (2) A. Kelman. Phytopathology 44:693, 1954.