bluuebunny/crossref_metadata_2025_split huggingface dataset:
First Report of Bacterial Blight of Romanesco Cauliflower (Brassica oleracea var. botrytis) Caused by Pseudomonas syringae pv. alisalensis in California
Authors: Koike S. T. , Kammeijer K. , Bull C. T. , O'Brien D. 
Published: May 2007

In 2005, a new disease was detected on commercial, organically grown romanesco (green) cauliflower (Brassica oleracea var. botrytis) grown in San Benito County, California. Initial symptoms consisted of small (1 to 2 mm in diameter), angular, water-soaked flecks. These flecks developed into tan-to-gray, angular lesions measuring as much as 5 mm in diameter. Lesions were usually surrounded by chlorotic borders. Coalescing lesions caused the leaf to turn papery in texture and have a blighted appearance. A blue-green fluorescing pseudomonad was consistently isolated from lesions on King's medium B. Strains were levan positive, oxidase negative, and arginine dihydrolase negative. Strains did not rot potato slices but induced a hypersensitive reaction in tobacco (Nicotiana tabacum cv. Samsun). These data indicated that the bacteria belonged to Lelliot's LOPAT group 1 (2). This was confirmed with data from fatty acid methyl ester analysis (MIS-TSBA version 4.10, MIDI, Inc., Newark, DE), which showed that the strains were highly similar (similarity = 0.921 or greater) to Pseudomonas syringae. Amplification of repetitive bacterial sequences (rep-PCR) using the BOXA1R primer and the polymerase chain reaction resulted in identical banding patterns for the romanesco strains and the P. syringae pv. alisalensis pathotype strain. Pathogenicity was demonstrated by growing inoculum of six strains in nutrient broth shake cultures for 48 h (24°C), adjusting the bacterial suspension to 106 CFU/ml, and spraying the resulting suspension onto green cauliflower (cv. Romanesco Precoce). Plants were enclosed in plastic bags for 24 h and then incubated in a greenhouse (24 to 26°C). Control plants were misted with sterile water and treated the same way. After 5 days, foliar symptoms identical to symptoms seen in the field developed on all inoculated plants, and reisolated strains were characterized and found to be identical to P. syringae pv. alisalensis by the tests described above. Control plants remained symptomless. The results of two sets of pathogenicity tests were the same. To our knowledge, this is the first report of commercially grown romanesco green cauliflower as a host of P. syringae pv. alisalensis. The infested field had approximately 30% of the plants affected, with perhaps 10% sustaining some crop loss. This bacterial pathogen has previously been reported on commercial plantings of arugula (Eruca sativa), broccoli (Brassica oleracea var. botrytis), and broccoli raab (Brassica rapa var. rapa) and under experimental (greenhouse) conditions causes disease on additional hosts, including members of the Poaceae (1). References: (1) N. A. Cintas et al. Plant Dis. 86:992, 2002. (2) R. A. Lelliott. J. Appl. Bacteriol. 29:470, 1966.
First Report of Phomopsis amygdali Causing Fruit Rot on Peaches in Greece
Authors: Michailides T. J. , Thomidis T. 
Published: May 2007

In the summer of 2005, the fungus Phomopsis amygdali (Del.) Tuset & Portilla was frequently isolated from decayed peaches (Prunus persica cv. Andross) grown in the province of Imathia, Greece. Fruit infected by P. amygdali developed gray-to-brown decay lesions with white mycelium forming on the surface of lesions. Identification of the pathogen was based on morphological characteristics. Dark-pigmented pycnidia (flask-shaped, conidia-bearing fruiting bodies) were produced over the surface of potato dextrose agar. The pycnidia exuded conidia in white tendrils 7 days later. Koch's postulates were completed in the laboratory by inoculating mature and immature cv. Andross peach fruits with an isolate of P. amygdali isolated from decayed cv. Andross peaches. Thirty peach fruit were surface sterilized by dipping them into 0.1% chlorine solution and allowing them to dry in a laminar flow hood. The peach fruit were wounded with a 2-mm diameter glass rod and a 40-μl drop of 5 × 105 conidia of P. amygdali per milliliter suspension was applied to the wound. Thirty control fruits were similarly wounded and inoculated with a 40-μl drop of sterile water. All inoculated and noninoculated fruit were incubated at 24 to 26°C for 7 days. Koch's postulates were satisfied when the same fungus was reisolated from 100% of inoculated mature and immature fruit that developed symptoms similar to diseased fruit collected from orchards. Although P. amygdali has been previously reported as a causal agent of canker disease (2) and fruit rots of peaches (1) in other countries, to our knowledge, this is the first report of the occurrence of P. amygdali causing a fruit rot of peaches in Greece. References: (1) Y. Ko and S. Sun. Plant Pathol. Bull. 12:212, 2003. (2) E. I. Zehr, Constriction canker. Page 31 in: Compendium of Stone Fruit Diseases. J. M. Ogawa et al., eds. The American Phytopathological Society, St. Paul, MN, 1995.
First Report of the Occurrence of Wheat dwarf virus in Wheat in China
Authors: Xie J. , Wang X. , Liu Y. , Peng Y. , Zhou G. 
Published: May 2007

In May of 2004 and 2005, several diseased wheat (Triticum aestivum L.) plants showing extreme dwarfing, various types of yellowing, and reduced or no heading were found in the breeding fields of the Institute of Crop Science, Shanxi Academy of Agricultural Sciences, Taiyuan, Shanxi Province, China. On the basis of these symptoms, infection with Wheat dwarf virus (WDV) was suspected. Total DNA was extracted from diseased plants with the DNeasy Plant Mini kit (Qiagen, Hilden, Germany). Primers were designed based on the WDV-Enkoping1 genome sequence (NC_003326) (1), including: 245f, 5′-CGACTACGCCTGGCGAACATTTG-3′ (residues 245–267); 806r, 5′-TCTGGCATTGCCTGTTTCGG-3′ (complementary to residues 787–806); 1381f, 5′-CAGTGACATCTTCGCCGGAG-3′ (residues 1381–1400); and, 1886r, 5′-ACTCCGTAAGCCTCGAATCC-3′ (complementary to residues 1867–1886). With primer pairs 245f/806r, 1381f/1886r, 245f/1886r, and 1381f/806r, PCR products of 560, 506, 1642, and 2,275 bp were expected, respectively. After amplification, fragments of the expected sizes were seen on 1% (w/v) agarose gels. The fragments were purified by using a DNA gel extraction kit (TaKaRa, Dalian, China) and cloned into the pGEM-T vector (Promega, Madison, WI). The plasmids were transformed into E. coli strain DH5α and plasmid DNA was isolated from overnight cultures by alkaline lysis. Insert sequences were determined using the dideoxynucleotide chain termination method with an automated sequencer (ABI BigDye 3.1, Applied Biosystems, Foster City, CA). At least three independently isolated clones were analyzed for each PCR product. The compiled 2,750 nt sequence (GenBank Accession No. DQ868525) was 98.1, 98.5, 97.8, and 97.9% identical to WDV-Enkoping1 (NC_003326), WDV-SE (X02869), WDV-B (AM040732), and WDV-F (AM040733), respectively. Therefore, the virus isolate (WDV-TY) was identified as WDV (genus Mastrevirus, family Geminividae). Wheat samples collected from different provinces from 2004-2006 were also infected with WDV as indicated by PCR using the same primer pairs. For Shijiazhuang (Hebei Province), Yangling (Shanaxi Province), Kunming (Yunnan Province), Yuncheng (Shanxi Province), Tianshui (Gansu Province), Gangu (Gansu Province), and Zhenzhou (Henan Province), 13 of 14, 6 of 6, 5 of 5, 4 of 4, 2 of 3, 1 of 2, and 1 of 1 samples were positive, respectively, indicating a broad distribution of WDV in China. To our knowledge, this is the first report of WDV in wheat in China. Reference: (1) A. Kvarnheden et al. Arch Virol. 147:205, 2002.
First Report of Bacterial Blight of Rutabaga (Brassica napus var. napobrassica) Caused by Pseudomonas syringae pv. alisalensis in California
Authors: Koike S. T. , Kammeijer K. , Bull C. T. , O'Brien Doug 
Published: May 2007

In 2005, commercial, organically grown rutabaga (Brassica napus var. napobrassica) in San Benito County, CA showed symptoms of a previously undescribed disease on approximately 30% of the plants. Initial symptoms consisted of small (1 to 2 mm in diameter), angular, water-soaked flecks that often were surrounded by chlorotic haloes. These flecks enlarged and coalesced into large, irregularly shaped, gray brown lesions that could be as long as 10 mm. Lesions were visible from both adaxial and abaxial leaf surfaces and generally retained the chlorotic borders. A blue-green fluorescing pseudomonad was consistently isolated from lesions on King's medium B. Eight isolates were characterized and were levan positive, oxidase negative, and arginine dihydrolase negative. Isolates did not rot potato slices but induced a hypersensitive reaction in tobacco (Nicotiana tabacum cv. Samsun). These data indicated that the bacteria belonged to Lelliot's LOPAT group 1 (2). This was confirmed with data from fatty acid methyl ester analysis (MIS-TSBA version 4.10; MIDI, Inc., Newark, DE) that showed that the isolates were highly similar (similarity = 0.922 or greater) to Pseudomonas syringae. Amplification of repetitive bacterial sequences (rep-PCR) using the BOXA1R primer and the polymerase chain reaction resulted in identical banding patterns for the rutabaga isolates and the P. syringae pv. alisalensis pathotype strain. Pathogenicity was demonstrated by growing inocula of six isolates in nutrient broth shake cultures for 48 h (24°C), adjusting the bacterial suspension to 106 CFU/ml, and misting the resulting suspensions onto rutabaga (cv. American Purple Top). Plants were enclosed in plastic bags for 24 h and then incubated in a greenhouse (24 to 26°C). Control plants were misted with sterile water and treated the same way. After 5 to 7 days, foliar symptoms similar to symptoms seen in the field developed on all inoculated plants, and reisolated bacteria were characterized and found to be P. syringae pv. alisalensis. Control plants remained symptomless. The results of two sets of pathogenicity tests were the same. To our knowledge, this is the first report of commercially grown rutabaga as a host of P. syringae pv. alisalensis and the first report of a B. napus host of this pathogen. This bacterial pathogen has previously been reported on commercial plantings of arugula (Eruca sativa), broccoli (Brassica oleracea var. botrytis), and broccoli raab (Brassica rapa var. rapa) in California and under experimental conditions it causes disease on additional hosts, including members of the Poaceae (1). References: (1) N. A. Cintas et al. Plant Dis. 86:992, 2002. (2) R. A. Lelliott. J. Appl. Bacteriol. 29:470, 1966.
First Report of Exserohilum rostratum Associated with Rice Seed in Venezuela
Authors: Cardona R. , González M. S. 
Published: May 2007

Rice (Oryza sativa L.) is an important cereal crop in Venezuela and is planted on approximately 200,000 ha. Fungal diseases caused by the Helminthosporium complex of fungi are considered a major constraint to rice production. In 2005, a blotter method was used to identify fungi associated with rice seed. Seeds (150) of cv. INIA-017 were placed on a plate with moistened filter paper and incubated at 26 ± 2°C with a 12-h light/12-h dark cycle for 5 days until fungal sporulation. Single spores were transferred to 2% water agar (WA). Germinated spores were then transferred to potato dextrose agar (PDA), and resultant colonies were preserved until used. To induce sporulation, 4-mm-diameter discs were cut from 72-h-old cultures, transferred to WA, and incubated at 26 ± 2°C for 48 h (modified technique of Alcorn [1]). Discolored seed yielded isolates of Bipolaris oryzae (Berda de Haan) Shoemaker and Exserohilum rostratum (Drechs.) Leonard and Suggs (2). Pathogenicity tests were performed on 60-day-old rice plants of cv. Blue Bonnet 50. Four plants per pot were used for each isolate. Before inoculation, plants were placed in humidity chambers for 48 h. Spores were harvested from discs into a beaker containing 50 mL of a dilute gelatin solution (Gelatin Difco; 5 g/100 mL of sterile distilled water [SDW]). Spore suspensions were filtered through cheesecloth and adjusted to 7 × 104 spores per ml. The inoculated plants were placed in humidity chambers for 72 h. Control plants were sprayed with SDW. Inoculated plants were removed from humidity chambers and placed on a greenhouse bench. Plants inoculated with B. oryzae were symptomatic 5 days after inoculation; resultant lesions were red-brown with chlorotic borders. Lesions subsequently turned gray with reddish borders and were rhombic in shape. Plants inoculated with E. rotratum were symptomatic 7 days after inoculation with elliptical lesions that were orange-brown along venation. These lesions turned gray with reddish borders. Both fungi were reisolated from symptomatic leaf tissue. To our knowledge, this is the first report of E. rostratum from rice in Venezuela. References: (1) J. L. Alcorn. Mycotaxon. 17:1, 1983. (2) A. Sivanesam. Mycol. Pap. 158, 1987.
First Report of Fusarium Wilt of Flue-Cured Tobacco Caused by Fusarium oxysporum f. sp. batatas in Spain
Authors: Rodríguez-Molina M. C. , Palo E. , Palo C. , Espárrago G. , Verdejo E. , Torres-Vila L. M. , García J. A. , Blanco I. 
Published: May 2007

Tobacco (Nicotiana tabaccum L.) is among the most important crops in La Vera Region (Cáceres, west-central Spain) where, since 2001, flue-cured tobacco plants showing typical symptoms of a vascular disease associated to the cyst nematode (Globodera tabacum) complex have been frequently observed (2). Symptoms observed were wilting, yellowing, and drying of the leaves, usually on one side of the plant; stunted and distorted leaves with curved midribs due to the unequal growth; and brown vascular discoloration of stems and midribs. Several diseased plants were collected during the summers of 2003 and 2004, and F. oxysporum was consistently isolated from sections of necrotic midribs. To confirm the pathogenicity of F. oxysporum isolates, plants of flue-cured tobacco (cv. Ct-681) were inoculated. Since Fusarium wilt of tobacco may be caused by F. oxysporum f. sp. vasinfectum or F. oxysporum f. sp. batatas (1), plants of cotton (cv. Acala) and sweet potato (cvs. Nemagold and Nancy Hall) were also inoculated to determine the forma specialis designation. Twenty plants per cultivar and isolate were inoculated with six isolates at the two to four true-leaf stage by pouring into the substrate 200 ml of a conidial suspension (1 × 105 CFU/ml). After inoculation, plants were incubated in a growth chamber at 28°C (day) and 24°C (night) with a 16-h photoperiod. All six F. oxysporum isolates were pathogenic to tobacco and sweet potato, but there were differences among isolates in time from inoculation to appearance of first disease symptoms (7 to 15 days after inoculation in tobacco and sweet potato) and also in disease severity 30 days after inoculation (60 to 100% wilt or mortality in tobacco and 50 to 100% in sweet potato). F. oxysporum was reisolated from stems of inoculated plants. No disease symptom was observed in cotton plants 60 days after inoculation, and F. oxysporum was not reisolated from them. Results of inoculation on the differential hosts indicated that disease symptoms in tobacco were caused by F. oxysporum f. sp. batatas. To our knowledge, this is the first report of F. oxysporum f. sp. batatas causing disease in flue-cured tobacco in Spain. References: (1) G. M. Armstrong and J. K. Armstrong. Phytopathology 58:1242, 1968. (2) G. Espárrago and I. Blanco. Plant Dis. 86:1402, 2002.
Downy Mildew Caused by Bremia lactucae on Strawflower (Helichrysum bracteatum) in California
Authors: Koike S. T. , Ochoa O. E. 
Published: May 2007

In 2006, field-planted strawflower (Helichrysum bracteatum (Venten.) Andr.) grown for cutflowers in coastal San Mateo County was severely infected with a downy mildew disease. Initial symptoms consisted of irregularly shaped chlorotic lesions. Lesions were typically vein delimited, and in particular, did not cross the central longitudinal vein of the lanceolate leaves. Lesions were large and could exceed 6 cm long. Profuse white sporulation developed on the abaxial sides of the lesions. As disease progressed, lesions became gray brown and necrotic. Cutflower stems having symptomatic foliage were unmarketable. Hyaline conidiophores emerged from stomata, branched dichotomously, and had branch tips ending in swollen vesicles bearing sterigmata. Conidia were hyaline and ovoid to globose in shape. The pathogen was identified as Bremia lactucae Regel. To establish pathogenicity, strawflower plants were spray inoculated with a conidial suspension of 1 × 104 conidia/ml, incubated for 24 h in a dew chamber (18 to 20°C), and then maintained in a greenhouse (22 to 24°C). After 14 days, symptoms and signs of downy mildew developed on inoculated plants and the pathogen was confirmed to be B. lactucae. Untreated control plants did not develop downy mildew. Because lettuce (Lactuca sativa L.) is grown extensively in this coastal region, we investigated the pathogenicity of B. lactucae from strawflower on lettuce by inoculating a lettuce downy mildew differential series that includes 20 lettuce lines, four wild L. serriola lines, and strawflower. A conidial suspension of 1 × 106 conidia/ml was applied to all plants; plants were then incubated in a growth chamber with irradiation at 15°C. After 14 days, only the strawflower plants showed downy mildew lesions and sporulation. Collected from diseased field-grown strawflower, 100 downy mildew conidia were measured and had dimensions of 24.4 × 17.4 μm. These conidia were significantly longer than the B. lactuca conidia collected from lettuce (21.8 × 18.1 μm) grown in a nearby area (LSD [P = 0.05] = 2.2), though dimensions were within the reported length range for B. lactucae (12 to 31 μm) (2). To our knowledge, this is the first report of downy mildew caused by B. lactucae on strawflower in California. Inoculation studies indicate that these strawflower and lettuce pathogens from California likely belong to distinct formae speciales (2), though a B. lactucae isolate in Italy was able to infect both hosts (1). The pathogen has been reported on strawflower in Florida, Egypt, Italy, and the United Kingdom (1). References: (1) A. Garibaldi et al. Plant Dis. 87:315, 2003. (2) W. M. Morgan. CMI Descriptions of Pathogenic Fungi and Bacteria. No. 682. CAB International, Wallingford, UK, 1981.
First Report of Iris yellow spot virus on Onion in New York
Authors: Hoepting C. A. , Schwartz H. F. , Pappu H. R. 
Published: May 2007

Iris yellow spot virus (IYSV [family Bunyaviridae, genus Tospovirus]), a potentially devastating disease of onion vectored by onion thrips (Thrips tabaci Lindeman), has been reported from most states in the western United States where significant onion production occurs, with the most recent report from Texas (1). In June 2006, volunteer onion (Allium cepa) plants in Orleans County, New York (Elba muckland) were found to have symptoms indicative of IYSV infection. The scapes (seed stalks) of the volunteer onions found at the edge of a cull pile from a 2005 onion crop exhibited diamond-shaped lesions, each with a distinct green center and a double yellow border. Approximately 25 of 100 plants of red and yellow onion cultivars exhibited characteristic IYSV lesions. The cull pile was composed primarily of locally grown onions, although a few of the bulbs were grown from imported bare-root transplants imported from Arizona. Symptomatic plants tested positive for IYSV using IYSV-specific antiserum from Agdia Inc. (Elkhart, IN) in a double-antibody sandwich-ELISA. The presence of IYSV was verified by reverse transcription (RT)-PCR using primers derived from the small RNA of IYSV (S-RNA). The primers flanked the IYSV nucleocapsid (N) gene (5′-TAA AAC AAA CAT TCA AAC AA-3′ and 5′-CTC TTA AAC ACA TTT AAC AAG CAC-3′ (3). RT-PCR assays produced a PCR amplicon of expected size (approximately 1.2 kb) and the product was cloned and sequenced. Nucleotide sequence analysis confirmed the identity of the amplicon as that of the IYSV S-RNA. Sequence comparisons showed 95 to 98% identity with known IYSV N gene sequences available in GenBank. The virus is poorly transmitted to onion by mechanical inoculation and we did not have access to a noninfested colony of the onion thrips vector to transfer the virus from these samples to noninfected onions. No asymptomatic plants were tested. Among the onion-growing states in the eastern United States, IYSV has previously only been reported from Georgia (2). To our knowledge, this is the first report of IYSV in New York and the greater northeastern United States. The finding of this disease in New York confirms further spread of the virus within North America and the need for research to develop more effective management options to reduce the impact of IYSV on onion crops. References: (1) M. Miller et al. Plant Dis. 90:1359, 2006. (2) S. W. Mullis et al. Plant Dis. 90:377, 2006. (3) H. R. Pappu et al. Arch. Virol. 151:1015, 2006.
First Report of Tobacco streak virus Infecting Guizotia abyssinica from India
Authors: Arun Kumar N. , Lakshmi Narasu M. , Zehr U. B. , Ravi K. S. 
Published: May 2007

Guizotia abyssinica (L.f.) Cass. (niger), an important oil seed crop grown in India, is used in foods, paints, soaps, and as an illuminant. During a survey conducted in 2004 to monitor Tobacco streak virus (TSV) in Helianthus annuus L. (sunflower) and Arachis hypogaea L. (groundnut), typical symptoms of leaf and petiole necrosis were observed in niger plants from Karnataka State, India. The field-collected samples reacted with TSV-specific polyclonal antiserum in direct antigen coated (DAC)-ELISA. Indicator host species were mechanically inoculated with extracts from symptomatic leaves and grown under greenhouse conditions. The inoculations resulted in local necrotic lesions on Vigna unguiculata cv. C-152 (cowpea), Gomphrena globosa, and Nicotiana tabacum cv. Xanthi (tobacco) at 3 to 4 days postinoculation (dpi) and systemic mosaic mottling on sunflower and G. globosa at 7 to 9 dpi. To identify the virus at the molecular level, total RNA was isolated (RNeasy kit, Qiagen Inc., Chatsworth, CA) from the virus-inoculated cowpea leaf and used for reverse transcription-PCR using TSV CP (coat protein) specific primers (2). The resulting ~720-bp amplicon corresponding to the CP gene of TSV was cloned into pGem-T vector (Promega, Madison, WI) and sequenced. The resulting sequence of the TSV-niger isolate (TSV-NG) comprised 717 nucleotides encoding 238 amino acid residues of the viral coat protein (GenBank Accession No. DQ864458). Comparison of the sequence with those of other TSV CP gene indicated 98.5 to 99.3% nucleotide and 97.9 to 99.6% amino acid sequence identity with TSV isolates from India (1,2; GenBank Accession Nos. AF505073, AY061930, AY061929, AF515823, AF515824, and AF515825). The sequence of TSV-NG had 89.5 and 80.0% amino acid identity with TSV-WC, type strain from the United States (GenBank Accession No. X00435) and TSV-BR, isolate from Brazil (GenBank Accession No. AY354406), respectively. On the basis of symptoms, transmission, and serological and molecular data, the causal agent of necrosis in niger was identified as a strain of TSV widely prevalent in other oil seed and vegetable crops in India. The new report of Tobacco streak virus infecting niger from India, indicated the expansion of host range among oil seed crops. References: (1) A. I. Bhat et al. Indian J Biotechnol. 1:350, 2002. (2) K. S. Ravi et al. Plant Pathol. 50:800, 2001.