bluuebunny/crossref_metadata_2025_split huggingface dataset:
Tomato spotted wilt virus Found in Five Species of the genus Tragopogon in a Florida Greenhouse
Authors: Baker C. A. , Jones L. , Leahy R. M. , Soltis D. E. 
Published: April 2009

An obviously unhealthy plant identified as Tragopogon mirus Ownbey (remarkable goatsbeard) was sent for diagnosis to the Division of Plant Industry (DPI), Gainesville, FL in May of 2008. T. mirus is a recently formed allotetraploid that has T. dubius Scop. and T. porrifolius L. (goatsbeard or salsify) as parents. The parents (family Asteraceae) are diploid and originate from Eurasia. They were introduced to the northwest United States in the early 1900s. The allotetraploid T. mirus, which does not occur in Eurasia, was discovered in 1949 and named in 1950. It has been found in the northwest states of Washington and Idaho. It has also been found in Arizona (4). The plant sent to the DPI was grown in a greenhouse for research purposes at the Botany Department of the University of Florida (Alachua County). Symptoms exhibited on the leaves included mottling, chlorotic and necrotic spots, and mild distortion. Epidermal leaf strips from a mottled leaf were stained with the Orange-Green protein stain and Azure A nucleic acid stain (1). With a light microscope, granular inclusions typical for Tomato spotted wilt virus (TSWV) (1) were seen in leaf strips from both stains. The remainder of the leaf was ground in buffer and tested serologically for TSWV by TSWV-specific ImmunoStrips (Agdia, Elkhart, IN). The ImmunoStrip was positive for the presence of TSWV. This test was confirmed by double-antibody sandwich-ELISA using antiserum and conjugate for TSWV (Agdia). Further serological testing of other Tragopogon species with similar symptoms growing in the same greenhouse revealed that T. miscellus (another recently formed allotetraploid found in the northwestern United States; parents T. dubius and T. pratensis), T. dubius, T. porrifolius, and T. pratensis were also infected with TSWV. Total RNA was extracted from symptomatic leaves of T. mirus, T. dubius, T. porrifolius, and T. miscellus. Reverse transcription-PCR was performed with universal tospovirus primers BR60 and BR65 that amplify part of the nucleocapsid protein gene (2). Target amplicons of 454 bp were produced for all four samples. The PCR product from T. porrifolius was cloned and sequenced. The resulting sequence (GenBank Accession No. FJ655913) shows high homology, 98%, to several isolates of the Tomato spotted wilt virus deposited in the GenBank (Accession Nos. AY870391, AY744477, and AF020659). T. porrifolius has been reported to be naturally infected with TSWV in Italy (3); however, to our knowledge, this is the first report of this virus in the allotetraploids T. mirus and T. miscellus and in the diploids T. dubius and T. pratensis. This report adds five new Asteraceae weeds to the list of possible reservoirs of TSWV in the United States. References: (1) J. R. Edwardson and R. G. Christie. Univ. Fla. Inst. Food Agric. Sci. Bull. 894. 1996. (2) M. Eiras et al. Fitopatol. Bras. 26:170, 2001. (3) G. Parrella et al. J. Plant Pathol. 85:227. 2003. (4) D. E. Soltis et al. Biol. J. Linn. Soc. 82:2004.
First Report of Fusarium solani Fruit Rot of Pumpkin (Cucurbita pepo) in Trinidad
Authors: Rampersad S. N. 
Published: April 2009

Trinidad is a major exporter of pumpkins (Cucurbita pepo L.) to other Caribbean countries, Canada, and the United States. Producers and exporters have reported 50 to 80% yield losses because of soft rot and overnight collapse of fruit at the pre- and postharvest stages. Severe fruit rot occurred in fields in Victoria County in South Trinidad between April and May 2006 (mid-to-late dry season) with an increase in the severity and number of affected fruit in the rainy season (July to December). Symptoms began as water-soaked lesions on the fruit of any age at the point of contact with the soil. The disease progressed to a soft rot with leakage and whole fruit collapse. A dark brown, soft decay also developed at the base of the main vines. Fusarium solani was isolated on selective fusarium agar and potato dextrose agar (PDA) (1) after 7 to 10 days of incubation at 25°C. The pathogen was identified by morphological characteristics and pathogenicity tests. Colonies were fast growing with white aerial mycelia and a cream color on the reverse side; hyphae were septate and hyaline, conidiophores were unbranched, and microconidia were abundant, thin walled, hyaline, fusiform to ovoid, generally one to two celled, and 8 to 10 × 2 to 4 μm. Macroconidia were hyaline, two to three celled, moderately curved, thick walled, and 25 to 30 × 4 to 6 μm. Pathogenicity tests for 10 isolates were conducted on 2-week-old pumpkin seedlings (cv. Jamaican squash; seven plants per isolate) and mature pumpkin fruit (2). Briefly, seedlings were inoculated by dipping their roots in a spore suspension (1 × 104 spores per ml) for 20 min. The plants were repotted in sterile potting soil. For negative controls, plant roots were dipped in sterile water. After the rind of fruit was swabbed with 70% ethanol followed by three rinses with sterile distilled water, 0.4-cm-diameter agar plugs of the isolates were inserted into wounds made with a sterile 1-cm-diameter borer. Sterile PDA plugs served as negative controls. Fruit were placed in sealed, clear, plastic bags. Inoculated plants and fruit were placed on greenhouse benches (30 to 32°C day and 25 to 27°C night temperatures) and monitored over a 30-day period. Tests were repeated once. Inoculated fruit developed a brown, spongy lesion that expanded from the initial wound site over a period of approximately 17 days after inoculation. White mycelia grew diffusely over the lesion. Inoculated plants developed yellow and finally necrotic leaves and lesions developed on stems at the soil line approximately 21 days after inoculation. No symptoms developed on the control plants. The fungus was reisolated from symptomatic tissue, fulfilling Koch's postulates. To my knowledge, this is the first report of Fusarium fruit rot of pumpkin in Trinidad. References: (1) J. Leslie and B. Summerell. Page 1 in: The Fusarium Laboratory Manual. Blackwell Publishing, Oxford, 2006. (2) W. H. Elmer. Plant Dis. 80:131, 1996.
Chalara fraxinea Isolated from Diseased Ash in Norway
Authors: Talgø V. , Sletten A. , Brurberg M. B. , Solheim H. , Stensvand A. 
Published: April 2009

European ash (Fraxinus excelsior), also known as common ash, occurs naturally inland in lower areas of southeastern Norway and along the southern coast of the country. It is important both as a forest and ornamental tree. During the last decade, dieback has become a disastrous disease on F. excelsior in many European countries. The anamorphic fungus Chalara fraxinea T. Kowalski (1), described for the first time from dying ash trees in Poland, is now considered the cause of ash dieback (2). In May of 2008, C. fraxinea was isolated from 1.5 m high diseased F. excelsior in a nursery in Østfold County in southeastern Norway. Symptoms included wilting, necrotic lesions around leaf scars and side branches, and discoloration of the wood. From symptomatic branches, small pieces (approximately 1 cm3) were excised in the transition area between healthy and discolored wood. After surface sterilization (10 s in 70% ethanol + 90 s in NaOCl), the pieces were air dried for 1 min in a safety cabinet, cut into smaller pieces, and placed on media. The fungus was isolated on potato dextrose agar (PDA) and water agar (WA). On PDA, the cultures were tomentose, light orange, and grew slowly (21 mm mean colony diameter after 2 weeks at room temperature). Typical morphological features of C. fraxinea developed in culture. Brownish phialides (14.8 to 30.0 [19.5] × 2.5 to 5.0 [4.1] μm, n = 50) first appeared in the center of the colonies on the agar plugs that had been transferred. The agar plugs were 21 days old when phialides were observed. Abundant sporulation occurred 3 days later. Conidia (phialospores) extruded apically from the phialides and formed droplets. Conidia measured 2.1 to 4.0 (3.0) × 1.4 to 1.9 (1.7) μm (n = 50). The first-formed conidia from each phialide were different in size and shape from the rest by being longer (6 μm, n = 10) and more narrow in the end that first appeared at the opening of the phialide. Internal transcribed spacer sequencing confirmed that the morphological identification was correct (Accession No. EU848544 in GenBank). A pathogenicity test was carried out in June of 2008 by carefully removing one leaf per plant on 10 to 25 cm high F. excelsior trees (18 trees) and placing agar plugs from a 31-day-old C. fraxinea culture (isolate number 10636) on the leaf scars and covering with Parafilm. After 46 days, isolations were carried out as described above from discolored wood that had developed underneath necrotic lesions in the bark and subsequently caused wilting of leaves. All the inoculated plants showed symptoms, and C. fraxinea was successfully reisolated. No symptoms were seen on uninoculated control plants (eight trees) that had received the same treatment except that sterile PDA agar plugs had been used. References: (1) T. Kowalski. For. Pathol. 36:264, 2006. (2) T. Kowalski and O. Holdenrieder, For. Pathol. Online publication, doi: 10.1111/j.1439-0329.2008.00565.x, 2008.
Identification of Lettuce big-vein associated virus and Mirafiori lettuce big-vein virus Associated with Lettuce Big-Vein Disease in Slovenia
Authors: Mavrič Pleško I. , Viršček Marn M. , Žerjav M. 
Published: April 2009

Lettuce big-vein disease (LBVD) is an important disease of lettuce (Lactuca sativa L.) worldwide. Two viruses are reported to be associated with the disease, Lettuce big-vein associated virus (LBVaV) and Mirafiori lettuce big-vein virus (MLBVV). The majority of publications shows that MLBVV is the causal agent of LBVD, but two plants with big-vein symptoms and infected only with LBVaV were found by Roggero et al. (2). Lettuce plants with big-vein symptoms were observed in a greenhouse in Ljubljana and in a private garden near Sežana. Chlorotic vein banding with deformations of leaves were observed and the plants were generally smaller than those without symptoms. The seedlings at the first location were grown in sterilized soil and showed no such symptoms. Six symptomatic plants and two seedlings without symptoms from the first location and three symptomatic plants from the second location were analyzed for the presence of LBVaV and MLBVV. Total RNA was isolated from 50 mg of lettuce leaf tissue with a RNeasy plant mini kit (Qiagen, Chatsworth, CA). Multiplex reverse transcription-PCR with primers VP248 (5′-CGCCAGGATCTTTGATCCATCTG-3′) and VP249 (5′-TTGCGACATGTTCCTCCTCATCG-3′) for LBVaV, VP286 (5′-TATCAGCTCACATACTCCCTATCG-3′) and VP287 (5′-CAACTAGCTCAGAATACATGCAG-3′) for MLBVV, and VP383 and VP389 for internal control (1), was performed. Mixed infections with MLBVV and LBVaV were detected in four plants and only MLBVV was detected in two plants from the first location. None of the viruses was detected in the two seedlings without symptoms. Mixed infections with MLBVV and LBVaV were detected in all analyzed plants from the second location. According to these results, only MLBVV could be correlated with observation of disease symptoms. To our knowledge, this is the first reported association of MLBVV and LBVaV with big-vein disease in Slovenia. MLBVV was the only virus found in all samples with big-vein symptoms. References: (1) J. A. Navarro et al. Phytopathology 94:470. 2004. (2) P. Roggero et al. Eur. J. Plant Pathol. 109:261, 2003.
First Report of Botrytis Blight Caused by Botrytis cinerea on Flowering Dogwood (Cornus florida) in Italy
Authors: Garibaldi A. , Bertetti D. , Gullino M. L. 
Published: April 2009

Flowering dogwood (Cornus florida L., Cornaceae), is a small deciduous tree whose showy inflorescences, clusters of bright red fruits and red and purple leaves in autumn, make it a much appreciated ornamental. In June of 2008, severe outbreaks of a previously unknown blight were observed in several private gardens near Biella (northern Italy) after a rainy spring with temperatures that ranged from 7 to 25°C. Dogwoods in the gardens were 10 to 15 years old, and the disease was observed on 20 to 30% of 30 trees. First symptoms consisted of blighted leaves and then shoot dieback. As the disease progressed, entire leaves became necrotic and were covered by an abundant, soft, gray, sporulating mycelium. Tissue fragments of 1 mm2 were excised from the margins of the lesions, immersed in a solution containing 1% sodium hypochlorite, plated on potato dextrose agar (PDA) medium, and incubated under constant fluorescent light at 22 ± 1°C for 10 days. Conidiophores were slender and branched with enlarged apical cells bearing smooth, ash-colored conidia 6 to 10 × 6 to 8 (average 9 × 7) μm on short sterigmata. A few, black, irregularly shaped sclerotia (3 to 5 × 1 to 2 mm) were produced on PDA plates incubated for 20 days at 8 ± 1°C. These morphological characteristics identified the fungus as Botrytis cinerea (2). The internal transcribed spacer (ITS) region of rDNA was amplified using primers ITS4/ITS6 and sequenced. BLAST analysis (1) of the 491-bp segment showed a 100% homology with the sequence of Botryotinia fuckeliana (perfect stage of B. cinerea). The nucleotide sequence has been assigned GenBank Accession No. FJ 572049. Pathogenicity tests were performed twice by placing mycelium fragments (1 cm2) of PDA cultures on 30 leaves of 6 healthy 3-year-old potted C. florida plants. Six plants inoculated with PDA alone served as controls. Plants were maintained outdoors at temperatures ranging between 15 and 22°C, spraying leaves with water three times a day. The first foliar lesions similar to those observed in the gardens developed 10 days after inoculation on 23 inoculated leaves, whereas control plants remained healthy. B. cinerea was consistently reisolated from these lesions. To our knowledge, this is the first report of the presence of B. cinerea on C. florida in Italy. The disease has been reported in the United States (4) as well as in Japan (3). At this time, the economic importance of Botrytis blight to flowering dogwoods in Italy is undetermined. References: (1) S. F. Altschul et al. Nucleic Acids Res. 25:3389, 1997. (2) H. L. Barnett and B. B. Hunter. Illustrated Genera of Imperfect Fungi. Burgess Publishing Company, Minneapolis, MN, 1972. (3) T. Kobayashi. Ann. Phytopathol. Soc. Jpn. 50:528, 1984. (4) C. Westcott. Plants Gard. 7:136, 1951.
Bacterial Stem Rot of Oncidium Orchid Caused by a Dickeya sp. (ex Pectobacterium chrysanthemi) in Mainland China
Authors: Li B. , Qiu W. , Fang Y. , Xie G. L. 
Published: April 2009

In December 2007, stem rot symptoms on orchids (Oncidium Gower Ramsey) were observed at a flower nursery in the Zhejiang Province of China. Initial symptoms were water-soaked lesions starting at the base of the stem. As these lesions expanded and elongated, the stem and leaf tissues became soft and watery. When examined with a microscope, cut edges of symptomatic stem and leaf tissues consistently exhibited bacterial streaming. The bacteria were isolated by streaking on nutrient agar (3). All isolates were gram-negative, facultative, anaerobic rods with peritrichous flagella. Infiltration of tobacco leaves (Nicotiana tabacum cv. Samsun) with the bacterial suspension of 108 CFU/ml resulted in typical hypersensitivity reactions within 24 h. Five representative isolates were further characterized by the Biolog Microbial Identification System, version 4.2 (Biolog Inc., Hayward, CA) and gas chromatography of fatty acid methyl esters (FAME) by the Microbial Identification System (MIDI Inc., Newark, DE) with aerobic bacterial library (TSBA50). The five isolates were identified as Erwinia chrysanthemi (Pectobacterium chrysanthemi) with a Biolog and FAME similarity index of 0.81 to 0.88 and 0.62 to 0.75, respectively. The transfer of P. chrysamthemi to a novel genus, Dickeya gen. nov., was recently proposed (2). The almost complete 16S rDNA sequence from Oncidium isolate SCH-01 (1,604 bp; EMBL Accession No. FM946179) was determined according to the method of Li et al. (1). A subsequent GenBank search showed that this isolate is 98% identical to that of type strain CFBP 1269T of Dickeya dadantii (EMBL Accession No. AF520707) and CFBP 1200T of Dickeya dianthicola (EMBL Accession No. AF520708). Nevertheless, species identification within genus Dickeya is still difficult since only a limited number of strains of each species have been characterized fully. Koch's postulates were completed with the inoculation of Oncidium seedlings with cell suspensions (108 CFU/ml) by a pinprick at the base of the stem. All five representative isolates induced stem rot similar to that observed in natural infections. No symptoms were noted on the control plants inoculated with sterilized distilled water by the same method. The bacterium was reisolated from symptomatic stems of Oncidium plants. To our knowledge, this is the first report of stem rot on Oncidium orchid in Mainland China caused by the bacterium formerly referred to as P. chrysanthemi, now proposed as Dickeya sp. References: (1) B. Li et al. J. Phytopathol. 154:711, 2006. (2) R. Samson et al. Int. J. Syst. Evol. Microbiol. 55:1415, 2005. (3) N. W. Schaad et al. Laboratory Guide for Identification of Plant Pathogenic Bacteria. 3rd ed. The American Phytopathological Society. St. Paul, MN, 2001.
First Report of Cercospora beticola as a Pathogen of German Statice (Goniolimon tataricum) in Bulgaria
Authors: Bobev S. G. , Groenewald J. Z. , Crous P. W. 
Published: April 2009

German statice (Goniolimon tataricum) is a protected, herbaceous, perennial plant species that occurs sporadically throughout Bulgaria. Some varieties, however, are cultivated outdoors because of their dry flowers, which are widely utilized by florists. For the past 3 years, a severe leaf disease has been observed on the lower and middle leaves of German statice plants growing in fields in the region of Plovdiv, Bulgaria. Symptoms consisted of brown, round to elliptical leaf spots (as much as 15 mm in diameter) that led to leaf yellowing and death. Similar sunken lesions were also observed on leaf petioles and flower bases. A cercosporoid fungus was consistently associated with disease symptoms. Conidiophores were fasciculate, unbranched, brown, and smooth. Conidiogenous cells were predominantly terminal, but also lateral, and had darkened, thickened, refractive scars. Conidia were solitary, hyaline, smooth, acicular, slightly curved, multiseptate, with subtruncate bases and acutely rounded apices, 30 to 105 × 2.5 to 4 (average 64.5 × 3.5) μm, in vivo (n = 30), with thickened, darkened, refractive hila. Colonies derived from single conidial isolates were established on potato dextrose agar (PDA). To confirm Koch's postulates, colonized mycelial plugs (5 mm in diameter) from 10-day-old PDA cultures were used to inoculate 3-month-old German statice pot plants (three replicates per treatment, three leaves per plant). Control plants were inoculated with uncolonized agar plugs. Healthy leaves were surface disinfested with 70% ethanol, wounded with a sterile needle, and covered with an agar plug. Inoculated plants were incubated at 20°C in a humidified chamber with a 12-h day/night light cycle. Eight to ten days after inoculation, small necrotic lesions developed around the points of inoculation, leading to necrosis and lesions (8 to 10 mm in diameter). The pathogen was successfully reisolated from all inoculated leaves, while control plants remained healthy. Five isolates (CPC 14616–14620) were subjected to multilocus sequence typing as described by Groenewald et al. (1) and the ITS, translation elongation factor 1-alpha, actin, calmodulin, and histone H3 gene sequences (GenBank Accession Nos. FJ473422–FJ473446) were found to be identical to that of the ex-type strain of Cercospora beticola Sacc. (GenBank Accession Nos. AY840527, AY840494, AY840458, AY840425 and AY840392, respectively). Two strains from Goniolimon were deposited in the CBS Fungal Biodiversity Centre in the Netherlands (CBS 123907 and 123908). To our knowledge, this is the first report of C. beticola occurring on and being destructive to Goniolimon tataricum under field conditions. Reference: (1) M. Groenewald et al. Phytopathology 95:951, 2005.
First Report of Verticillium Wilt of Gold Kiwifruit, Actinidia chinensis Cv. Hort 16A, Caused by Verticillium albo-atrum in Chile
Authors: Auger J. , Pérez I. , Fullerton R. A. , Esterio M. 
Published: April 2009

Gold kiwifruit, Actinidia chinensis Planch cv. Hort 16A, was first planted in Chile in 2003 and vines started dying within 2 years. By the end of the 2007–2008 growing season, as much as 80% of the plants in several orchards had died. The disease was characterized by a conspicuous reddish brown discoloration of the xylem and the sudden wilting and dieback of plants any time during the growing season. In the spring, entire plants or parts of plants failed to break buds. In others, the buds broke, but juvenile leaf clusters then wilted and died. On severely affected plants, scion watershoots wilted and died. The disease was often accompanied by shallow cracking of the bark and slight sponginess of the underlying cortex. The disease was apparently most severe in sites that had been planted to Gold kiwifruit immediately after removal of apple, pear, citrus, or grape. Orchards planted following long-term maize, wheat, or grass culture were almost disease free. A fungus was consistently isolated from symptomatic vascular tissue disinfected in 1% sodium hypochlorite and plated on potato dextrose agar. Conidiogenous cells were arranged in verticels; conidia were hyaline, elliptical, single celled, and measured 3.5 to 8.5 × 1.8 to 4.3 μm (average 5.5 × 2.5 μm). Dark, resting mycelium developed after 1 to 2 weeks of incubation. On the basis of these morphological characteristics, the fungus was identified as Verticillium albo-atrum Reinke & Berthier. Identification was confirmed by sequencing part of the internal transcribed spacer (ITS) region with primers ITS1 and ITS4. The sequence of a representative isolate showed high homology (98% identity over a length of 494 bp) with a DNA fragment (NCBI Accession No. 108476) of V. albo-atrum from alfalfa. To complete pathogenicity tests, 20 healthy, 1-year-old Hort 16A kiwi vines grafted on Hayward kiwifruit (A. deliciosa Chevalier) seedlings were inoculated by injection of 20 μl of 106 conidia/ml into stems of the scion. Twenty control plants were injected with an equal volume of sterile distilled water. Plants were held in a controlled environment facility at 24°C with 16 h of light per day. Eight weeks after inoculation, typical wilting and dieback symptoms developed on 90% of the plants. Control plants injected with water remained healthy. Verticillium wilt has never been reported on kiwifruit (A. deliciosa) in Chile. V. albo-atrum has a rather narrow host range and is mainly reported as a pathogen on alfalfa, hop, soybean, tomato, and potato (1). To our knowledge, this is the first report of V. albo-atrum causing wilt and dieback on Gold kiwifruit (A. chinensis) cv. Hort 16A. The fungal isolates have been deposited in the Plant Pathology Laboratory of the Sanidad Vegetal Department of Agricultural Sciences Faculty of University of Chile under the name Actinidia chinensis/V. albo-atrum No. 1 to 8. Reference: (1) E. K. Ligoxigakis et al. Phytoparasitica 30:511, 2002.