bluuebunny/crossref_metadata_2025_split huggingface dataset:
Reservoir Weed Hosts for Turnip mosaic virus in Iran
Authors: Farzadfar Sh. , Ohshima K. , Pourrahim R. , Golnaraghi A. R. , Sajedi S. , Ahoonmanesh A. 
Published: May 2007

During the summer of 2003, weed samples of Rapistrum rugosum and Sisymbrium loeselii showing severe mosaic, malformation, and stunting were collected from cauliflower fields in Tehran Province of Iran. Using double-antibody sandwich enzyme-linked immunosorbent assay (DAS-ELISA) with specific polyclonal antibodies, the samples were tested for the presence of Beet western yellows virus, Cauliflower mosaic virus, Radish mosaic virus, Turnip crinkle virus, Turnip mosaic virus (TuMV) (DSMZ, Braunschweig, Germany), Cucumber mosaic virus, and Tobacco mosaic virus (Sanofi Diagnostics Pasteur, Marnes-La-Coquette, France). Leaf extracts were used for mechanical inoculation and they produced chlorotic local lesions on Chenopodium amaranticolor, necrotic lesions on leaves and shoot apex necrosis on Nicotiana glutinosa, leaf deformation, mosaic, and stunting on Petunia hybrida, and severe mosaic, distortion, and stunting on Brassica rapa. These symptoms were similar to those that were described previously for TuMV (4). ELISA results showed that the original leaf samples and inoculated indicator plants reacted positively with TuMV antibodies, but not with antibodies for any of the other viruses listed above. Also, reverse transcription-polymerase chain reaction of total RNA extracted from the collected leaf samples using the universal primers for potyviruses (3) resulted in the amplification of two fragments of the expected sizes, approximately 700 and 1,700 bp. TuMV, a member of the genus Potyvirus in the family Potyviridae, is transmitted by aphids in a nonpersistent manner (4). This virus is geographically widespread with a wide host range that can infect 318 species in 156 genera of 43 plant families including, Brassicaceae, Chenopodiaceae, Asteraceae, Cucurbitaceae, and Solanaceae (2,4). R. rugosum and S. loeselii, two annual or biennial plants in the Brassicaceae family, were common and widely distributed in the fields surveyed. The presence of TuMV-infected weed hosts in cauliflower fields may impact disease management strategies. TuMV was first observed on stock plants (Matthiola sp.) in Iran (1). To our knowledge, this is the first report of natural occurrence of TuMV on weed hosts in Iran. References: (1) M. Bahar et al. Iran. J. Plant Pathol. 21:11, 1985. (2) J. R. Edwardson and R. G. Christie. The potyvirus group. Fla. Agric. Exp. Stn. Monogr. Ser. No. 16, 1991. (3) A. Gibbs and A. Mackenzie. J. Virol. Methods 63:9, 1997. (4) J. A. Tomlinson. Turnip mosaic virus. No. 8 in: Descriptions of Plant Viruses. CMI/AAB, Surrey, England, 1970.
First Report of a Leaf Spot and Stem Canker Caused by Myrothecium roridum on Watermelon in the United States
Authors: Seebold K. W. , Langston D. B. , Kemerait R. C. , Hudgins J. E. 
Published: May 2007

Myrothecium roridum Tode:Fr, pathogenic to a number of cucurbit species, causes fruit rots, cankers on crowns and stems, and leaf spots. Hosts include cantaloupe and honeydew (Cucurbita melo) and cucumber (Cucumis sativus) (1,3). In June 2004, following a period of heavy rainfall, numerous round-to-oblong, brown lesions with concentric rings were observed on leaves of watermelon (Citrullus lanatus) cv. Desert King at the Blackshank Farm in Tifton, GA. Disease was localized in the field and severity was low (<5% of leaf area affected). No symptoms were observed on fruit. Sections of tissue were removed from the margin between healthy and diseased tissue and plated on acidified, 25% potato dextrose agar (aPDA). A small plug of agar and mycelium were removed from colonies that emerged from lesions and were transferred to aPDA. Isolated colonies were characterized by a white, floccose mycelium with concentric, dark green-to-black rings of sporodochia bearing viscid masses of conidia. Conidia were cylindrical with rounded ends and measured 6 to 8 × 1.5 to 2.5 μm. The features of the fungus were consistent with the description of Myrothecium roridum (1,2). Pathogenicity tests were conducted in a temperature-controlled greenhouse. Twenty-five watermelon plants (cv. Desert King) were inoculated with a conidial suspension of M. roridum (5 × 105 conidia per ml) plus 0.1% vol/vol Tween 20. Inoculum was applied on leaves and stems until runoff with a hand-held mister, and plants were placed in a dew chamber for 72 h. Ten plants were sprayed with sterile, distilled water to serve as controls. Inoculated and noninoculated control plants were removed from the dew chamber and maintained at 25 to 28°C. Symptoms appeared 8 days after inoculation and were characterized by round, dark lesions with concentric rings; noninoculated plants were symptomless. Sections of symptomatic tissue were plated, and M. roridum was reisolated. Although M. roridum is a common pathogen of melons and cucumber, to our knowledge, this is the first field report of a leaf spot caused by M. roridum on watermelon in the United States. No further occurrences of the disease on watermelon have been observed in Georgia since the initial discovery of M. roridum in 2004; however, losses could be potentially severe if widespread infection of fruit were to occur. References: (1) B. D. Bruton. Crater Rot. Pages 49–50 in: Compendium of Cucurbit Diseases. T. A. Zitter et al., eds. The American Phytopathological Society, St. Paul, MN, 1996. (2) M. B. Ellis. Page 552 in: Dematiaceous Hyphomycetes. CAB International, Wallingford, UK, 1971. (3) D. F. Farr et al. Page 809 in: Fungi on Plants and Plant Products in the United States. The American Phytopathological Society, St. Paul, MN, 1989.
Powdery Mildew Caused by Leveillula taurica on Glossy Leaf Genotypes of Onion in Idaho
Authors: Mohan S. K. , Molenaar N. D. 
Published: May 2007

Onion (Allium cepa L.) plants growing in a breeding nursery in Canyon County, Idaho were observed with leaf symptoms of powdery mildew in August and September, 1994. The affected leaves showed roughly circular, 10- to 15-mm-diameter, powdery, white-to-grayish white patches with irregular margins. The leaf area under the fungal growth turned chlorotic and later necrotic. Occasionally, lesions coalesced, covering larger areas of the leaf surface. Symptoms were seen on mature and young leaves. Of 620 lines examined, only the 10 lines which had glossy leaves (no or low levels of cuticular wax) displayed symptoms of powdery mildew. Microscopic examination revealed that the white, powdery growth on the lesions consisted entirely of conidiophores and conidia. Conidiophores emerged through stomata, singly or in groups of two or three, were branched, and bore either terminal, pyriform (59 to 68 × 16 to 19 μm), apically pointed (lanceolate) primary conidia or cylindrical (57 to 62 × 18 to 20 μm) secondary conidia. On the basis of the presence of endophytic mycelium, morphological characteristics of the conidiophores, and the dimorphic conidia the fungus was identified as Leveillula taurica (Lev.) G. Arnaud (1) (anamorph = Oidiopsis sicula Scalia). The teleomorph of this fungus was not observed. Greenhouse inoculations were made onto leaves of three 8-week-old plants of a glossy leaf onion genotype (94P240) and three 6-week-old plants of tomato (cv. Payette) grown in pots. Conidia from sporulating lesions on onion leaves were brushed onto the leaves, and the inoculated plants were covered with a plastic bag for 72 h to maintain high humidity. Inoculated leaves on both hosts developed chlorotic lesions with sporulation of L. taurica after 14 days at 25 to 28°C. Noninoculated onion and tomato plants (one of each) did not develop powdery mildew symptoms. This selective susceptibility of onion genotypes with glossy leaves to L. taurica warrants careful consideration by onion breeding programs in utilizing such germ plasm as a potential source for other desirable characters such as nonpreference to thrips. To our knowledge, this is the first report of powdery mildew of onion caused by L. taurica in Idaho. This disease has been reported on onions in California (3) and Washington (2). However, it has not been observed in commercial onion crops in Idaho, even though the cultivars involved apparently vary as to the amount of cuticular wax on their foliage. References: (1) H. J. Boesewinkel. Bot. Rev. 46:167, 1980. (2) L. J. du Toit et al. Online publication. DOI: 10.1094/PHP-2004-1129-01-HN. Plant Health Progress, 2004. (3) F. F. Laemmlen and R. M. Endo. Plant Dis. 69:451, 1985.
First Report of Papaya ringspot virus and Zucchini yellow mosaic virus in Luohanguo (Siraitia grosvenorii) in China
Authors: Liao Y.-M. , Gan X.-J. , Chen B. , Cai J.-H. 
Published: May 2007

Luohanguo, Siraitia grosvenorii (Swingle) C. Jeffrey, is a perennial cucurbitaceous plant that is an economically important medicinal and sweetener crop in Guangxi province, China. Surveys conducted during the summer to fall seasons of 2003-2004 in northern Guangxi showed symptoms typical of a viral disease, including leaf mottling, mosaic, vein clearing, curling, and shoestring-like distortion in the field. Mechanical inoculation of sap from leaves of symptomatic plants collected from the surveyed areas caused similar symptoms on tissue culture-derived healthy Luohanguo plants. Two sequences of 0.7 and 1.6 kb with 88 and 97% identity to Papaya ringspot virus (PRSV) and Zucchini yellow mosaic virus (ZYMV) were amplified using reverse transcription-polymerase chain reaction (RT-PCR) with purified flexuous viral particles or total RNA extracted from the symptomatic Luohanguo leaves as templates with conserved degenerate potyvirus primers (1). To confirm the results, primers specific for PRSV (PP1/PP2, genome coordinates 4064-4083/5087-5069, GenBank Accession No X97251) and ZYMV (ZP1/ZP2, genome coordinates 5540-5557/7937-7920, GenBank Accession No L31350) were used to perform RT-PCR from the same RNA templates. The expected 1.0- and 2.3-kb fragments were amplified and they were 90 and 95% identical to PRSV and ZYMV in sequence, respectively. Watermelon mosaic virus was not detected. To our knowledge, this is the first report of the occurrence of PRSV and ZYMV in Luohanguo. Reference: (1) A. Gibbs et al. J. Virol. Methods 63:9, 1997.
First Report of Witches'-Broom Disease of Sesame (Sesamum indicum) in Oman
Authors: Al-Sakeiti M. A. , Al-Subhi A. M. , Al-Saady N. A. , Deadman M. L. 
Published: May 2007

Sesame is the major oil seed crop in Oman. During 2004, disease symptoms were observed at Nizwa, 175 km south of Muscat. Symptoms included phyllody and excessive development of short shoots and internodes resulting in little leaves. Total genomic DNA was extracted from healthy and symptomatic plants with a modified cetyltrimethylammoniumbromide (CTAB) buffer method (2). DNA samples were assayed by polymerase chain reaction (PCR), with the 16S rDNA amplified using primers P1 and P7. Direct PCR products were used as template DNA for nested PCR with primers R16F2n and R16R2. Direct PCR products were analyzed by restriction fragment length polymorphism (RFLP) with four restriction enzymes, Tru9I, HaeIII, HhaI, and RsaI. DNAs from alfalfa and lime plants infected by witches'-broom phytoplasmas were used as positive controls and DNA from healthy plants and water were negative controls. The results showed the presence of a 1.8-kb product amplified with the direct PCR and a 1.2-kb product of the nested PCR from infected sesame and the positive controls. No PCR product was observed in the negative control. The PCR assay confirmed the presence of phytoplasma causing witches'-broom disease in sesame. The RFLP results showed the sesame phytoplasma to be most similar to the alfalfa phytoplasma, a member of 16SrII group (1). To our knowledge, this is the first report of a phytoplasma of the 16Sr II group causing witches'-broom disease on sesame in the Sultanate of Oman. References: (1) A. J. Khan et al. Phytopathology 92:1038, 2002. (2) M. A. Saghai-Maroof et al. Proc. Natl. Acad. Sci. USA, 81:8014, 1984.
First Report of Pathogenicity Groups 3 and 4 of Leptosphaeria maculans on Canola in North Dakota
Authors: Bradley C. A. , Parks P. S. , Chen Y. , Fernando W. G. D. 
Published: May 2007

Blackleg, caused by Leptosphaeria maculans (Desmaz) Ces. & de Not (anamorph = Phoma lingam), is an economically important disease of canola (Brassica napus L.) worldwide and was first detected in North Dakota in 1991 (3). L. maculans can be categorized into one of several pathogenicity groups (PGs) on the basis of the interaction phenotypes in differential canola cvs. Westar, Glacier, and Quinta by using a standard screening protocol in the greenhouse (4). With this system, PG1 strains are weakly virulent and PG2, PG3, and PG4 are highly virulent. The predominant strains of L. maculans in North Dakota are PG1 and PG2 (3). In cooperation with the Oilseed Pathology Lab in the Department of Plant Science, University of Manitoba, blackleg-infested canola stubble was collected arbitrarily from fields in North Dakota during August and September of 2003. Isolates of the pathogen were obtained by plating surface-sterilized (2% NaOCl), collected stubble on V8 agar containing 0.03% chloramphenicol at 22°C under continuous cool-white fluorescent light. Pycnidiospores were harvested from single pycnidia after 14 days of incubation with the Miracloth filtering method (2) and stored at -20°C. Each isolate was passed once through cv. Westar to maintain virulence. Isolates were confirmed as being L. maculans by the presence of characteristic pink pycnidia formed on V8 agar and the characteristic symptoms caused on inoculated cotyledons of cv. Westar. The PG test was performed using a standard screening protocol (4) and was repeated three times for each isolate. For each isolate, 12 7-day-old cotyledons of each differential cultivar were wound inoculated with 10 μl of a pycnidiospore suspension (1 × 107 per ml). Disease severity on cotyledons was assessed 12 days after inoculation with a 0 to 9 scale (0 to 2 = resistant; 3 to 6 = intermediate; and 7 to 9 = susceptible). A total of 106 isolates were obtained from the stubble collected from 47 fields. Of these isolates, three were characterized as PG1, 94 as PG2, six as PG3, and one as PG4; two isolates could not be characterized according to the PG system as described (4). PG3 isolates originated from two fields in Cavalier County and one field in Ward County. The PG4 isolate was from Cavalier County. To our knowledge, this is the first time highly virulent strains of PG3 and PG4 have been detected in North Dakota. PG3 and PG4 strains of L. maculans were found only recently in western Canada (1,2). The discovery of these PGs in North Dakota and western Canada has immense implication to canola breeding programs and blackleg control, since these PGs may cause greater levels of blackleg severity on canola cultivars that are resistant to only PG2 type isolates. References: (1) Y. Chen and W. G. D. Fernando. Plant Dis. 89:339, 2005. (2) W. G. D. Fernando and Y. Chen. Plant Dis. 87:1268, 2003. (3) H. A. Lamey and D. E. Hershman. Plant Dis. 77:1263, 1993. (4) A. Mengistu et al. Plant Dis. 75:1279, 1991.
Natural Occurrence of a Potyvirus on Murraya koenigii in India
Authors: Chandel V. , Hallan V. , Zaidi A. A. 
Published: May 2007

Murraya koenigii (L.) Spreng., a small, strong-smelling umbrageous tree with subcampanulate white flowers belonging to the family Rutaceae, is native to India and southeastern Asia (2). It is distributed across the Indian subcontinent excluding the higher elevations of the Himalayas. In India, the leaves are mainly used for culinary purposes. The leaves are commonly known as curry leaves or ‘sweet neem’. The whole plant including bark, root, leaves, fruits, and fruit pulp is used medicinally. This plant was reported to be a host of Citrus tristeza virus (1). In a survey of potyvirus incidence in the northwestern Himalaya foothills of the Kangra and Hamirpur districts in the state of Himachal Pradesh in 2004, M. koenigii plants showing mosaic symptoms on leaves, typical of a virus infection, were frequently observed. Symptomatic leaves were tested for the presence of several viruses using enzyme-linked immunosorbent assay with specific antibodies. Positive results were obtained with potyvirus group specific antibodies (Agdia, Elkhardt, IN) in triplicate analyses of 5 of 15 leaf samples tested. To further identify the infecting virus, RNA from plants was tested using universal potyvirus primer pair P9502 and CPUP (3) and reverse transcription-polymerase chain reaction to amplify a genome fragment encoding portions of the coat protein and the 3′UTR (3). An amplification product of the expected size (~800 bp) was obtained. The product was cloned into the pGem-T easy vector (Promega, Madison, WI), and three clones were sequenced. The sequence (GenBank Accession No. AJ852504) had 92% identity to Chili vein banding mottle virus, a potyvirus infecting pepper reported from Thailand (GenBank Accession No. U72193). To our knowledge, this is the first report of a potyvirus naturally occurring on a Murraya sp. References: (1) K. Balaram and K. Ramakrishnan. Curr. Sci. 48:453, 1979. (2) J. D. Hooker. Flora British India 1:502, 1875. (3) R. A. A. van der Vlugt et al. Phytopathology. 89:148, 1999.
Outbreak of Powdery Mildew on Common Sage in Argentina
Authors: Madia M. , Gaetán S. 
Published: May 2007

Common sage, Salvia officinalis L., is produced primarily in greenhouses for the culinary herb market in Argentina. Since 2003 during autumn and winter, powdery mildew symptoms have been repeatedly observed on potted common sage plants in commercial greenhouses located on the outskirts of Buenos Aires. The average disease incidence during this period was 85 to 90%. Circular, white, powdery patches developed on leaf surfaces and stems. Heavily infected leaves turned brown and died. Hyaline mycelium and nonlobed appressoria were observed. Conidiophores were simple with straight foot cells measuring 53.0 to 80.0 × 10.0 to 12.3 μm. Conidia were aseptate, hyaline, cylindrical to ovoid, measured 33.0 to 40.5 × 15.0 to 18.5 μm, did not contain fibrosine bodies, and were produced in chains. Cleistothecia were not observed. The pathogen was identified as Erysiphe cichoracearum DC (1). Pathogenicity was confirmed by gently pressing leaves displaying abundant sporulation onto the adaxial surface of healthy leaves. After 10 to 12 days, typical signs and symptoms of powdery mildew appeared on all inoculated plants. Pathogenicity tests were conducted in a greenhouse at 20 to 23°C and included 10 sage plants (five inoculated and five noninoculated). The experiment was performed twice, each time with the same result. Control plants did not show any signs or symptoms. E. cichoracearum DC was previously reported in the United States on Salvia sp. (2).To our knowledge, this is the first report of an outbreak of powdery mildew caused by E. cichoracearun on potted common sage plants produced in greenhouses in Argentina. References: (1) H. J. Boesewinkel. Rev. Mycol. Tome 41:493, 1977. (2) D. F. Farr et al. Fungi on Plants and Plant Products in the United States. The American Phytopathological Society, St. Paul, MN, 1989.
First Report of Bacterial Leaf Spot Caused by Pseudomonas cichorii on Phlox paniculata in Italy
Authors: Garibaldi A. , Bertetti1 D. , Scortichini M. , Gullino M. L. 
Published: May 2007

Phlox paniculata L. (fall phlox) is a perennial garden species belonging to the Polemoniaceae family. During the spring of 2003 and 2004, leaf spot symptoms were observed on fall phlox plants in some private gardens in the Biella area (northern Italy). Lesions were first observed on leaves at the collar level and later on the entire plant. Lesions started as water-soaked areas, which in few days developed on the upper side of the leaves into irregular, shrunken, reddish brown spots from 1 to 2 mm in diameter. Lesions on the lower surface sometimes had a translucent halo. In many cases, the leaves were completely withered. Disease was particularly severe during the spring and fall and its incidence ranged from 10 to 25%. No fungal structures were observed within the lesions. Small fragments of tissue from affected leaves were macerated in nutrient yeast dextrose broth (NYDA), and dilutions of the resulting suspension were streaked onto NYDA and potato dextrose agar (PDA). Isolations were made from at least 25 leaves. Plates were maintained at 22 ± 1°C for 48 h. No fungi were isolated from the spots on NYDA or PDA. Colonies typical of Pseudomonas species were consistently isolated on NYDA. Isolates were negative for levan, potato soft-rot (pectolytic activity), and arginine dehydrolase while positive for oxidase and hypersensitivity on tobacco leaves. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis of whole-cell protein analysis (1) indicated that the bacterium isolated was similar to Pseudomonas cichorii (Swingle) Stapp NCPPB 943 and 3283 strains. On King's medium B, (2) a typical fluorescent pigment was produced. The pathogen was identified as Pseudomonas cichoriii. Pathogenicity of 10 colonies was tested by growing inoculum in nutrient-broth shake cultures for 48 h, suspending bacterial cultures in water, diluting to 106 CFU/ml, and spraying 10 1-year-old healthy plants of P. paniculata. Ten control plants were sprayed with sterile nutrient broth. Inoculated and control plants were kept covered with plastic bags for 72 h. After 8 days in a growth chamber at 20 ± 1°C, leaf spots identical to those observed in the field developed on leaves of inoculated plants. Control plants remained symptomless. The pathogenicity test was repeated once. Bacteria were reisolated from the spots and identified as P. cichoriii. To our knowledge, this is the first record of bacterial leaf spot of Phlox paniculata in Italy as well as in the world. References: (1) D. H. Bergey et al. Bergey's Manual of Determinative Bacteriology. Williams and Wilkins, Baltimore, MD, 1994. (2) E. O. King et al. J. Lab. Clin. Med. 44:301, 1954.