bluuebunny/crossref_metadata_2025_split huggingface dataset:
First Report of the Quarantine Brown Rot Pathogen Monilinia fructicola on Imported Stone Fruits in Switzerland
Authors: Bosshard E. , Hilber-Bodmer M. , Schärer H.-J. , Bünter M. , Duffy B. 
Published: May 2007

Monilinia fructicola, causal agent of fruit brown rot, is a quarantine pathogen in Europe (1). It presents a significant threat because of its aggressivity on flowers, shoots, and wood at low temperatures and propensity for sexual reproduction that increases potential for evolutionarily adaptation to new environments, hosts, and fungicides. It is common in North America, Japan, Australia, and South America. It occurs in orchards in France, has been detected but eradicated from Austria and Spain, and has been found on imported peach in Hungary (1,2). In Switzerland, we recently detected M. fructicola in supermarkets on imported fruit with brown rot symptoms similar to those caused by endemic M. fructigena and M. laxa. Preliminary identification was based on distinctive colony and conidial morphology on potato dextrose agar of fruit isolates. Specific identification was determined by polymerase chain reaction (PCR) (3) and sequencing the internal transcribed spacer (ITS) region. Koch's postulates were fulfilled by reproducing brown rot on healthy inoculated fruit. Surveys of imported fruit in markets (n = 42) using PCR revealed M. fructicola on all imported apricot and nectarine from the United States and France, but none on apricot, peach, plum, and cherry from Spain, France, Italy, or Turkey. Field surveys of apricot, peach, plum, prune, nectarine, and cherry orchards in 13 Swiss cantons were all negative (n = 71 in 2003 and 164 in 2005). This report demonstrates that imported fruit is a weak link in quarantine efforts and poses a potential threat. Transmission to local trees via highly dispersible, profuse spores from recycled packaging and disposal sites for discarded fruit has thus far not occurred but the risk deserves attention. Revised regulations for fruit treatment at points of entry and/or scrutiny of origin orchards may be warranted. References: (1) OEPP/EPPO. List of A2 pests regulated as quarantine pests in the EPPO region. Version 2005-09. Online publication with distribution map at http://www.eppo.org , 2005. (2) M. Petróczy and L. Palkovics. Plant Dis. 90:375, 2006. (3) K. J. D. Hughes et al. EPPO Bull. 30:507, 2000.
First Report of Leaf Rust by Puccinia triticina on Wheat in Oman
Authors: Deadman M. L. , Al Sa'di A. , Al Maqbali Y. , Aime M. C. 
Published: May 2007

Wheat (Triticum aestivum L.), cultivated for forage and grain production, is an important crop in the Sultanate of Oman. In April 2005, leaf samples of an unknown local variety showing rust symptoms were collected from Rustaq, 100 km southwest of Muscat. Circular-to-oval, red-brown pustules, typical of uredinia, occurred mostly on the upper surface of leaves on plants nearing maturity. Telia with teliospores were observed on leaf sheaths. The disease was widespread in many fields and was likely to be limiting the yield. Urediniospores typical of Puccinia triticina Erikss. (=P. recondita Rob. ex Desm. f. sp. tritici) were roughly subglobose, measuring 18 to 28 × 20 to 25 μm, echinulate, with 3 to 8 scattered germ pores; teliospores were 2-celled, 34 to 50 × 15 to 17 μm, apex is chestnut brown, lower cell is light yellow, no germ pores (1,2). Pathogen identity was confirmed by nuclear ribosomal large subunit and internal transcribed spacer region-2 DNA analysis (voucher sequence deposited in GenBank, Accession No. DQ664194, voucher specimens deposited in the U.S. National Fungus Collections, BPI 872158 and 872159). Wheat is grown during the winter months in Oman and harvested in May. Although the disease was observed again in 2006, pathogen survival mechanisms are not presently clear, and current research is attempting to confirm its presence on alternate hosts, including grass weeds, and determine the distribution of the pathogen on local wheat land races and imported varieties. To our knowledge, this is the first documented report of P. triticina on wheat in Oman. Reference: (1) D. B. O. Savile. Fungi Can. 309:1, 1986. (2) M V Wiese. Compendium of Wheat Diseases. The American Phytopathological Society, St Paul, MN, 1987.
First Report of Witches'-Broom Disease in a Cannabis spp. in China and Its Association with a Phytoplasma of Elm Yellows Group (16SrV)
Authors: Zhao Y. , Sun Q. , Davis R. E. , Lee I.-M. , Liu Q. 
Published: May 2007

Hemp fiber plants (Cannabis spp.) spread naturally in almost every climate zone in China and have a long history of cultivation in the country (1). While hemp stalks provide high-quality fibers for making ropes, clothes, and paper products, hemp seeds are a rich source of edible oil. During the summer of 2004, a disease characterized by witches'-broom symptoms was observed in wild hemp fiber plants growing in suburban Taian, Shandong, China. The diseased plants developed clusters of highly proliferating branches with much shortened internodes and leaves on the affected branches were significantly reduced in size. Phytoplasma infection was suspected in this hemp fiber witches'-broom (HFWB) disease because of the typical symptoms and because of its geographic location where other phytoplasmal diseases such as jujube witches'-broom (JWB), paulownia witches'-broom (PaWB), paper mulberry witches'-broom (PMWB), and Chinese wingnut witches'-broom (CWWB) diseases were previously reported (3,4). Total DNA was extracted from leaves of four diseased and four nearby healthy looking hemp fiber plants. Nested PCR were carried out on the DNA samples using phytoplasma universal 16S rDNA primers (P1A/16S-SR and R16F2n/R16R2) (2). Results revealed that all examined diseased plants were infected by phytoplasma, whereas nearby healthy looking plants were phytoplasma free. Subsequent restriction fragment length polymorphism (RFLP) analysis of the PCR-amplified 1.25-kb 16S rDNA R16F2n/R16R2 fragment indicated that the phytoplasma associated with HFWB disease belongs to subgroup 16SrV-B of the elm yellows (EY) phytoplasma group. Nucleotide sequence analysis of the cloned HFWB phytoplasma partial rRNA operon (GenBank Accession No. EF029092), spanning a near full-length 16S rRNA gene and a partial 16S-23S rRNA intergenic spacer, suggested that HFWB phytoplasma is most closely related to JWB and PMWB phytoplasmas, both members of subgroup16SrV-B. To further characterize the HFWB phytoplasma, a genomic segment covering full-length ribosomal protein genes rplV and rpsC was PCR-amplified using primer pair rp(V)F1A/rp(V)R1A (2), cloned, and sequenced (GenBank Accession No. EF029093). The nucleotide sequence of the HFWB phytoplasma rplV and rpsC locus is nearly identical (99.9%) to that of JWB phytoplasma. To our knowledge, this is the first report of a phytoplasmal disease in Cannabis spp. Since HFWB and JWB phytoplasmas share extremely high sequence identity and share the same eco-geographic location, further investigation is warranted to determine whether these two phytoplasmas are actually one species that can infect both plants, an issue having important implications in managing both diseases. References: (1) S. Hong and R. C. Clarke. J. Int. Hemp Assoc. 3:55, 1996. (2) I. M. Lee et al. Int. J. Syst. Evol. Microbiol. 54:337, 2004. (3) Q. Liu et al. Plant Dis. 88:770, 2004. (4) Q. Liu et al. Plant Dis. 89:529, 2005.
Natural Occurrence of Cucumber mosaic virus on Rauvolfia serpentina, A New Record
Authors: Raj S. K. , Kumar S. , Pratap D. , Vishnoi R. , Snehi S. K. 
Published: May 2007

Rauvolfia serpentina, family Apocynaceae, is widely cultivated in India and adjoining countries for the production of roots used in several herbal formulations (1). Severe mosaic and stunting of the whole plant was observed on R. serpentina growing in experimental plots of NBRI, Lucknow, in 2006. The causal pathogen was transmitted by sap inoculation on Nicotiana tabacum cv. White Burley, N. rustica, and N. glutinosa, which produced necrotic local lesions and systemic mosaic. The virus reacted positively with antiserum of Cucumber mosaic virus (CMV; PVAS 242a, ATCC, Manassas, VA) in gel double diffusion tests, indicating the presence of CMV. Total RNA was isolated from infected and healthy leaf tissues of R. serpentina, and reverse transcription (RT)-PCR was performed using CMV specific primers AM180922/AM180923. RT-PCR resulted in an expected size (~650 bp) amplicon in infected but not healthy samples. The amplicon was cloned, sequenced, and the data was submitted to GenBank (Accession No. DQ914877). BLAST search analysis of the virus isolate showed highest (99%) sequence identity with CMV isolates (GenBank Accession Nos. DQ640743, AF350450, X89652, and AF281864). The virus isolate showed a close phylogenetic relationship with Indian isolates of CMV belonging to subgroup IB. A literature survey revealed that there is no report of occurrence of any virus on R. serpentina except some fungal infections (2). To our knowledge, this is the first record of natural occurrence of CMV on R. serpentina. References: (1) Anonymous. Wealth of India 8:376, 1969. (2) R. S. Shukla et al. EPPO Bull. 36:11, 2006.
First Report of Helminthosporium solani Causing Silver Scurf of Potato in Hebei Province, North China
Authors: Tian S. M. , Chen Y. C. , Zou M. Q. , Xue Q. 
Published: May 2007

Silver scurf disease of potato (Solanum tuberosum) caused by Helminthosporium solani Durieu & Mont. occurs worldwide. Severe occurrence of the disease, the resulting weight loss of stored potatoes, and lower market classes of potato caused by the fungus have been documented in Europe and North America (1). Tubers infected with the pathogen develop tan-to-gray lesions that have a characteristic silvery appearance when moist. In 2005, gray spots with a defined margin and silvery appearance when seen against light were observed on potato tubers of cv. Weishu No. 1. The silver symptoms were distinguished from those of black rot disease of potato caused by Colletotrichum coccodes. The potato tubers were obtained from Weichang County of Hebei Province, North China. Conidia were scraped from the spots with a sterile scalpel and identified primarily as the fungus H. solani on the basis of morphological characters of the spores. The fungus was isolated, purified, and cultured on potato dextrose agar (PDA) amended with penicillin and streptomycin. To produce conidia, the fungus was incubated on V8 juice medium at 20 ± 2°C for 15 days under near-UV light (360 to 400 nm, 12-h light/dark cycles). The culture colony developed slowly and is gray to brown. Conidia form in whorls on conidiophores that are black, unbranched, irregular, and multiseptate. Conidia are appreciably tapered, straight or slightly curved, brown, thick walled, and have two to eight pseudosepta. The size of the conidia ranged from 14 to 70 μm long and 4 to 9 μm wide. The spore suspension was adjusted to 1.5 × 105 spores per ml by using sterile distilled water containing 0.2% Tween 20. Twenty healthy tubers were washed with distilled water and then inoculated by spraying the spore suspension onto the surface with a hand atomizer, while 10 washed tubers were sprayed with distilled water as controls. Inoculated tubers were kept in containers covered with plastic and placed in an incubation chamber at 20°C for 3 weeks. Gray-to-brown blemishes with a silvery appearance as described above were observed on tubers inoculated with the fungus and the tuber surface areas infected were from 1 to 10%, whereas no infection was visible on tubers inoculated with water. The causal agent was reisolated, cultured, and identified microscopically as H. solani. H. solani has been identified from potato tubers in Yunnan Province, Southwest China (2), but to our knowledge, this is the first report of H. solani causing silver scurf of potato in Hebei Province, North China. References: (1) D. Errampalli et al. Plant Pathol. 50:141, 2001. (2) K. Y. Ryu et al. China Potato. 15:195, 2001.
First Report of Tan Spot of Wheat Caused by Pyrenophora triticirepentis in the Northern Hills and Northwestern Plains Zones of India
Authors: Singh D. P. 
Published: May 2007

Tan spot of wheat, caused by Pyrenophora tritici-repentis (Died.) Drechs. (anamorph Drechslera tritici-repentis), is an important disease of wheat especially in cooler countries of the world. The fungal pathogen produces necrotic and chlorotic symptoms on different wheat genotypes. A survey was done to detect this disease in India during seven crop seasons (1999-2006). Blighted leaf samples (1,600) from 257 genotypes were collected from 46 locations in six agroclimatic zones of India. The tan spot pathogen was identified from scrapings of necrotic spots placed on glass slides and examined and from fungal growth on 2-cm pieces of infected leaves incubated on water-soaked Whatman No. 1 filter paper in presterilized transparent plastic petri dishes that were incubated for 3 days with a regimen of 21°C and 24 h of light and 16°C and 24 h of dark. On incubated leaf pieces, the pathogen produced erect, single, dark yellow-brown conidiophores with single, light yellow-brown conidia, 5 to 9 distoseptae, 75 to 200 μm, and a basal cell with a snake-like head typical of D. tritici-repentis(2). Disease incidence data revealed that the tan spot was most common in the northern hills zone (comprising the states of Uttaranchal, Himachal Pradesh, Jammu, and Kashmir) as well as in the Kalimpong locality in West Bengal. The pathogen was isolated from 26 to 83% of 374 leaf samples from the northern hills zone and 5 to 11% of 560 leaf samples from the northwestern plains zone (comprising the states of Punjab, Haryana, Western Uttar Pradesh, and Rajasthan). Suspensions of single-spored cultures grown on V8 potato dextrose agar with 3,000 conidia/ml until runoff were inoculated with a fine atomizer on 2-week-old seedlings of A-9-30-1 and Katepwa wheat genotypes in a polyhouse at the Directorate of Wheat Research, Karnal, India. Tween 20 (one drop per 100 ml of suspension) was used before inoculation. Necrotic and chlorotic symptoms that developed on the plants confirmed pathogenicity of the cultures. The pathogen has previously been reported from the northern plains and central zones of India during 1934 and 1972, respectively, (3,4) and from Pakistan during 2000 (1). The currently used practices of zero tillage and incorporation of crop residue back into fields may promote tan spot in the future. With the possibility that tan spot may become a major problem, particularly in the cooler parts of India, we recommend that the future wheat varieties to be planted in the northern hills and plains zones be screened for susceptibility to tan spot and that resistant varieties be developed to minimize possible loss. References: (1) S. Ali et al. Plant Dis. 85:1031, 2001. (2) C. Drechsler. J. Agric. Res. 24:641, 1923. (3) A. P. Misra and R. A. Singh. Indian Phytopathol. 25:350, 1972. (4) M. Mitra. Indian J. Agric. Sci. 4:692, 1934.
First Report of Bacterial Speck of Tomato Caused by Pseudomonas syringae pv. tomato in Tanzania
Authors: Shenge K. C. , Mabagala R. B. , Mortensen C. N. , Stephan D. , Wydra K. 
Published: May 2007

In April 2004, there was a serious outbreak of a tomato (Lypersicon esculentum Mill.) leaf spot disease in Mgeta, Mvomero District of Tanzania. The disease was characterized by lesions on green tomato fruits that were small, sunken, and black and were surrounded by darker green haloes. Lesions on ripe tomato fruits were dark brown to black, superficial, and measured approximately 1 to 2 mm in diameter. On the leaves, lesions were small, black, and surrounded by chlorotic (yellow) haloes. In some cases, the specks coalesced to form large lesions on older leaves. Black lesions were also observed on stems and petioles. A disease survey of selected tomato-producing areas in Arusha, Dodoma, Iringa, and Morogoro regions of Tanzania during 2004 and 2005 revealed that the disease was widespread in farmers' fields in all areas surveyed. Disease incidence was approximately 80%, while severity, rated on the scale of Chambers and Merriman (1), ranged from moderate (11 to 40 lesions per plant) to severe (>40 lesions per plant). A bacterium that produced a greenish, diffusible pigment on King's medium B was consistently isolated from lesions on tomato fruits collected from the fields in all the surveyed areas. All 56 isolates obtained were gram negative, oxidase negative, and fluoresced on King's medium B under UV light. None utilized phenylethylamine as the sole carbon source, while three isolates utilized i-erythritol and lactulose. Biolog analysis of the isolates, along with two reference strains of P. syringae pv. tomato (Pst CEP-3 from Sokoine University of Agriculture, Tanzania and Pst BB6 [Race 1] from Göttinger Sammlung Phytopathogener Bakterien, Göttingen, Germany) identified them as P. syringae pv. tomato, with similarity indices of 0.518 to 0.933. They also were positively identified as P. syringae pv. tomato by repetitive sequence-based-PCR (2,3) and fragment length polymorphism analysis. Pathogenicity of the strains was confirmed by spraying 35-day-old tomato seedlings (cv. Tanya) with suspensions of the isolates at a concentration of 108 CFU ml-1 of sterile water. After approximately 72 h, small, water-soaked, dark brown lesions similar to those observed on the field plants were observed on leaves of all the inoculated tomato seedlings. There were no symptoms on control plants. The bacterium was reisolated from the infected plants and identified as P. syringae pv. tomato, in accordance with Koch's postulates. To our knowledge, this is the first report of the occurrence of tomato bacterial speck in Tanzania. References: (1). S. C. Chambers and P. R. Merriman. Aust. J. Agric. Res. 26:657, 1975. (2). F. J. Louws et al. Appl. Environ. Microbiol. 60:2286, 1994. (3). M. Zaccardelli et al. Eur. J. Plant Pathol. 111:85, 2005.
First Report of Leaf Spot Caused by Cladosporium herbarum on Centaurea solstitialis in Greece
Authors: Berner D. K. , Smallwood E. L. , McMahon M. B. , Luster D. G. , Kashefi J. 
Published: May 2007

Centaurea solstitialis L. (yellow starthistle), family Asteraceae, an invasive weed in California and the western United States, is targeted for biological control. In the summer of 2003, an epidemic of unknown etiology on dying C. solstitialis plants was observed near Kozani, Greece (40°22′07″N, 21°52′35″E, elevation, 634 m). Plants had necrotic light brown leaf spots on the lower leaves and the decurrent leaf bases along the stems. Often, necrotic lesions extended along the stems to the capitula. Virtually all plants in a solid stand of C. solstitialis (approximately 0.5 ha) showed disease symptoms. Diseased plants were collected, air dried, and sent to the quarantine facility of the Foreign Disease-Weed Science Research Unit (FDWSRU), USDA/ARS, Fort Detrick, MD. On the basis of culture growth (45-cm diameter after 2 weeks at 25°C on malt extract agar), fungal morphology (1), and comparison with 21 internal transcribed spacer sequences in GenBank, the putative causal organism was identified as Cladosporium herbarum (Pers.:Fr.) Link. (teleomorph = Davidiella tassiana (De Not.) Crous & U. Braun). Sixteen C. solstitialis plants in the rosette stage and 16 plants in the bolted stage were inoculated with an aqueous suspension of spores (106 conidia ml-1) and placed in an environmentally controlled chamber at 25°C with 8 h of dew and 12 h of light daily. Plants in the rosette stage were resistant, but the fungus was very aggressive on bolted plants. Within 4 to 6 days of inoculation, necrosis developed on leaves and stems and then spread up the stems to the capitula, often resulting in plant death. The fungus also infected developing flowers. Cladosporium herbarum was reisolated from each of the 16 bolted C. solstitialis plants in two separate tests at the FDWSRU and from all bolted inoculated plants at the European Biological Control Laboratory (EBCL) in Greece. In the greenhouse at the EBCL, the pathogen readily spread to (and was isolated from) another 10 noninoculated C. solstitialis plants in close vicinity to the inoculated C. solstitialis plants. Results of host range tests will establish if this isolate of Cladosporium herbarum has the potential as a biological control agent of C. solstitialis in the United States and does not pose a threat to other Centaurea spp. used in horticulture. A voucher specimen has been deposited with the U.S. National Fungus Collections (BPI 863446). Live cultures are being maintained at the FDWSRU and EBCL, Greece. To our knowledge, this is the first report of a disease caused by Cladosporium herbarum on C. solstitialis. Reference: (1) M. H. M. Ho et al. Mycotaxon 72:115, 1999.
First Report of Blackberry chlorotic ringspot virus in Rubus sp. in the United States
Authors: Tzanetakis I. E. , Postman J. D. , Martin R. R. 
Published: May 2007

Blackberry chlorotic ringspot virus (BCRV), genus Ilarvirus, has been found in Rubus sp. in Scotland (2) and rose in the United States (4). The possibility that BCRV infects other hosts in the United States was explored. We tested 18 accessions of Fragaria sp. and 30 of Rubus sp. maintained at the National Clonal Germplasm Repository in Corvallis, OR. Ilarviruses had been detected in these plants by reverse transcription (RT)-PCR, ELISA, or had caused symptoms typical of ilarviruses on indicator plants. The accessions were tested by RT-PCR with primers F (5′-GTTTCCTGTGCTCCTCA-3′) and R (5′-GTCACACCGAGGTACT-3′) (4) that amplify a 519 to 522 nt (depending on the isolate) region of the RNA 3 of BCRV. The virus was detected in two accessions of black raspberry (Rubus occidentalis L.): RUB433, cv. Lowden and RUB 9012, cv. New Logan. The sequences of the fragments amplified from these accessions (GenBank Accession Nos. EF041817 and EF041818, respectively) had 97% nt sequence identity to each other and 95 and 88% nt identity to the rose and Scottish isolates (GenBank Accession Nos. DQ329378 and DQ091195, respectively). Chenopodium quinoa indicator plants inoculated with isolate RUB 433 developed mild chlorotic spots on the inoculated leaves 4 days after inoculation. RT-PCR and sequencing of the amplicons verified BCRV infection of C. quinoa. RUB 9012 was used for the characterization of Black raspberry latent virus (BRLV), later thought to be an isolate of Tobacco streak virus (TSV). This accession was recently found to be infected with Strawberry necrotic shock virus (SNSV) but not TSV (3). It is possible that BRLV may be a mixture of SNSV and BCRV. SNSV is one of the most abundant viruses of Rubus sp. in the Pacific Northwest (1), and the finding of another ilarvirus, BCRV, may account in part for the rapid decline of Rubus sp. observed in several fields in Oregon and Washington. To our knowledge, this is the first report of BCRV infecting Rubus sp. outside the United Kingdom. References: (1) A. B. Halgren. Ph.D. Diss. Oregon State University, Corvallis, OR, 2006. (2) A. T. Jones et al. Ann. Appl. Biol. 149:125, 2006. (3) I. E. Tzanetakis et al. Arch. Virol. 149:2001, 2004. (4) I. E. Tzanetakis et al. Plant Pathol. 55:568, 2006.