bluuebunny/crossref_metadata_2025_split huggingface dataset:
First Report of Powdery Mildew on Heath Aster Caused by Erysiphe cichoracearum in Argentina
Authors: Wolcan S. , Ronco L. 
Published: May 2007

In 1995, powdery mildew was observed on commercial greenhousegrown Aster ericoides L. from La Plata, Buenos Aires Province. The disease affected about 95% of the growers. Mildew first appeared as white circular patches on the adaxial surface of leaves. As disease progressed, the abaxial surface of leaves, petioles, stems, and calyces were covered by cottony masses of mycelium and conidia, and basal leaves later wilted and died. Young plants (4 to 5 leaves) through flowering plants were affected. Conidia were ovoid-cylindrical, often slightly constricted at the ends, and were produced in chains on unbranched conidiophores. Conidia lacked fibrosin bodies and ranged from 30 to 41 μm × 10 to 19 μm. Long unbranched germ tubes were formed from the ends of conidia. The morphological characteristics of the fungus fit those described for Erysiphe cichoracearum DC (1). In addition, the perfect stage was found on older tissues. Subglobose, dark brown cleistothecia (105 to 210 μm in diameter) with a basal ring of myceloid appendages were observed. Cleistothecia contained multiple ellipsoid asci (48 to 69 μm × 30 to 37 μm) with two hyaline, one-celled, ellipsoid ascospores (22 to 26 μm × 11 to 15 μm). Pathogenicity was tested by pressing diseased leaves onto healthy leaves of aster cv. Sunset and incubating plants in humidity chambers for 48 h. The powdery mildew that developed was morphologically identical to the original isolate. This is the first report of E. cichoracearum on heath aster in Argentina. Reference: (1) H. J. Boesewinkel. Bot. Rev. 46:167, 1980.
Occurrence of Maize rayado fino virus in Maize in Argentina
Authors: Giménez-Pecci M. P. , Oliveira E. , Resende R. , Borgogno C. , Nome C. F. , Laguna I. G. 
Published: May 2007

Symptoms of fine chlorotic stipple-striping of the veins, chlorosis, numerous dots and stripes, formation of holes in the leaf blade, and ears reduced in size, bearing few grains, were observed in maize crops in Tafí del Valle (Tucumán Province), Orán, El Galpón (Salta Province), Tilcara and Yaví (Jujuy Province), the subtropical area of northwest Argentina where the leafhopper vector Dalbulus maidis (DeLong & Wolcott) is present. Maize rayado fino virus (MRFV) was detected in these samples by a positive reaction in double antibody sandwich-enzyme-linked immunosorbent assay (DAS-ELISA) using an AGDIA kit. Electron microscopy revealed abundant isometric particles about 30 nm in diameter in the cytoplasm and vacuoles of phloem cells and xylem parenchyma cells. The virus was also detected by reverse transcription polymerase chain reaction (RT-PCR) using a primer pair MRFV-09/MRFV-10. Primers and PCR conditions were as previously described (1). Virus amplification was observed only in samples from symptomatic plants. In 1981 (2), the presence of MRFV in Argentina was revealed by serological assay in plants from temperate central areas. No further reports were released since then. This is the first evidence of MRFV in subtropical areas of Argentina and identification of the virus by combining DAS-ELISA, particle size, relation with plant tissues, and RTPCR. References: (1) R. W. Hammond et al. J. Gen. Virol. 78:3153, 1997. (2) S. F. Nome et al. RIA XIX:257, 1984.
A Severe Outbreak of Tobacco mosaic virus in Georgia's Flue-Cured Tobacco
Authors: Pappu H. R. , Bertrand P. F. , Moore J. M. 
Published: May 2007

During the 2000 growing season, tobacco plants showing blotching of the leaves with light and dark green areas suggestive of Tobacco mosaic virus (TMV) infection were observed in several counties in Georgia. Symptomatic plants appeared in the field within 4 weeks after transplanting. The incidence in individual fields was as high as 100%. A survey was conducted in several tobacco-growing counties, and the presence of TMV was verified by enzyme-linked immunosorbent assay (ELISA). Symptomatic plants were collected from the following 20 counties: Appling, Bacon, Berrien, Coffee, Colquitt, Cook, Echols, Evans, Grady, Irwin, Jeff Davis, Lanier, Lowndes, Montgomery, Pierce, Tattnall, Tift, Toombs, Ware, and Wayne. Of the 79 samples tested by ELISA, TMV was found to be present in 76 samples. This high degree of incidence of TMV in Georgia's tobacco has not been observed in the past. Although the specific reasons are not clear, all severe cases of TMV were observed in two varieties, NC71 and NC72, or plants of other varieties out of beds or plant houses that held these two varieties and were clipped with the same mower. While TMV and Potato virus Y (PVY) were found most prevalent in Georgia's flue-cured tobacco in 1999 (2), none of the plants tested were positive for PVY in 2000. Cucumber mosaic virus was reported to be more common in Florida during the last 3 years (1). The severe outbreak of TMV highlights the importance of preventive measures such as observing sound sanitation practices. References: (1) T. A. Kucharek et al. Plant Dis. 82:1172, 1998; (2) H. R. Pappu et al. Plant Dis. 84:201, 2000.
First Report of Sclerotium rolfsii on Jerusalem Cherry (Solanum pseudocapsicum) in Europe
Authors: Garibaldi A. , Minuto A. , Gullino M. L. 
Published: May 2007

Jerusalem cherry (Solanum pseudocapsicum) has recently become popular as a potted ornamental plant in Italy. During the summer of 1999, a sudden wilt of 60-day-old plants was observed in the Albenga region (Northern Italy), an area of intensive floriculture. Initial symptoms included stem necrosis at the soil line and yellowing and tan discoloration of leaves. As stem necrosis progressed, infected plants wilted and died. Necrotic tissues were covered with whitish mycelium that differentiated into reddish brown, spherical (1 to 2 mm diameter) sclerotia. Sclerotium rolfsii was consistently recovered from the surface of symptomatic stem sections that were disinfected for 1 min in 1% NaOCl and then plated on potato-dextrose agar (PDA) amended with 100 ppm streptomycin sulfate. Pathogenicity of three S. rolfsii isolates was confirmed by inoculating 90-day-old S. pseudocapsicum plants grown in pots. Inoculum consisted of mycelium and sclerotia of the pathogen placed on the soil surface around the base of each plant. Noninoculated plants served as controls. All plants were kept in a growth chamber at 18 to 28°C and RH > 85%. Inoculated plants developed symptoms within 7 days, while control plants remained symptomless. Sclerotia developed on infected tissues and S. rolfsii was reisolated from symptomatic tissues. The disease has been observed in the United States (1), but this is the first report of stem blight of S. pseudocapsicum caused by S. rolfsii in Europe. Reference: (1) S. A. Alfieri, Jr., K. R. Langdon, C. Wehlburg, and J. W. Kimbrough, J. W. Index Plant Dis. Florida Bull. 11:215, 1984.
Leaf Spot Disease of Broad Bean Caused by Alternaria tenuissima in Japan
Authors: Honda Y. , Rahman M. Z. , Islam S. Z. , Muroguchi N. 
Published: May 2007

In April 1999, a leaf spot of broad bean (Vicia faba L.) was observed in commercial fields in Shimane prefecture of Western Japan. Lesions were concentric and brown in color. Older leaves were particularly affected. In later stages of the disease, plants defoliated as leaves blighted from margin to the center. Isolation was made from infected leaf tissue. The isolated fungus produced conidia on V8 medium (2) either in dark or under continuous irradiation of near ultraviolet radiation (NUV) from BLB fluorescent lamps. Conidial chains were unbranched or rarely formed a few lateral branches with a few conidia. The conidia of the fungus grown under continuous NUV were dark and smoothly tapered into the apical beak, and each conidium had a conspicuously thickened primary septum with a constriction of the conidial wall and often a darker median transverse septum. The conidia measured 21.2 to 45.5 μm (mean = 32.9 μm) × 7.3 to 17.7 μm (mean = 11.4 μm ) on V8 medium. Conidia produced on leaves and stem collected from field were similar in size and appearance. The fungus was identified as Alternaria tenuissima based on its cultural and morphological characteristics (2). An isolate was also sent to CABI Bioscience Identification Services (Egham, UK), which also identified the fungus as A. tenuissima. A conidial suspension (107 spores/ml) was prepared and used to inoculate detached leaves and intact plants of broad bean. Intact plants were inoculated by spaying with spore suspension and covered with polyethylene bags for maintaining high humidity. Detached leaves in moist petri dishes were inoculated with drops of spore suspension. Symptom developed on both detached and intact leaves 3 to 4 days after inoculation. Reisolating the pathogen from infected leaves completed Koch's postulates. In June 2000, the leaf spot was observed in all 15 fields surveyed in other areas of Shimane prefecture. In some fields, plants were defoliated and stems and pods were also infected. Isolates of A. tenuissima also were obtained from those fields. This pathogen has been isolated from other hosts in Japan (1). This is the first report of A. tenuissima on broad bean in Japan. References: (1) Anonymous. 2000. Common Names of Plant Diseases in Japan. The Phytopathological Society of Japan, Tokyo. (2) E. G. Simmon. Mycotaxon 37:79–119, 1990.
First Report of Soybean Rust (Phakopsora pachyrhizi) in Nigeria
Authors: Akinsanmi O. A. , Ladipo J. L. , Oyekan P. O. 
Published: May 2007

Rust caused by Phakopsora pachyrhizi H. & P. Sydow was observed for the first time on soybean (Glycine max [L.] Merr.) in Nigeria during the 1999 main soybean growing season. The disease was first noticed on soybean farms in Oniyo and neighboring villages located about 20 km west of Ogbomoso (Long. 4° 02′ E and Lat. 8° 06′ N), Oyo State, Nigeria. The area falls under the moist savanna vegetation with a bimodal rainfall pattern (from April to July, September to November) and an annual mean rainfall of 1,370 mm. Commercial cultivation of soybean by farmers in the area started in 1986. A similar disease outbreak in 1999 on soybean in Benue state, the major area of soybean production in Nigeria, could not be confirmed to be rust. In the Oniyo area, soybean is commonly grown as an early season crop usually planted between March and April in small plots to produce seeds for the main crop, normally planted in July. Rust was not observed on the early season soybean crop grown in the area in 1999. Symptoms were first observed on leaves close to the ground in September 1999 as chlorotic spots, which progressed to reddish brown lesions, then uredia. The symptoms appeared further up the plant until all the leaves were infected. Pimple-like uredia observed in the lesions were more pronounced and numerous on the lower surface of the leaves than on the upper leaf surface. Uredia were noted to cluster together in clumps (1). The urediospores released from a central ostiole in the uredia were hyaline and oblong, 17 μm wide (15 to 18 μm) and 22 μm long (19 to 25 μm). Premature defoliation occurred on infected plants. Seed weight of TGX 1485-1D, TGX 1448-2E, and TGX 1440-1E was reduced by 28, 52, and 49%, respectively. Disease severity was higher on the medium maturing cultivars and all those that were planted late. Reference: (1) J. B. Sinclair. 1983. Compendium of Soybean Diseases, 2nd ed. The American Phytopathological Society, St. Paul, MN.
First Report of Armillaria mellea s. str. in Hardwood Forests of Southern Ontario
Authors: McLaughlin J. A. 
Published: May 2007

Armillaria mellea sensu stricto (Vahl:Fr.) Kummer has been found infrequently in studies conducted in northeastern North America (2) and it was not found in an earlier survey of northern Ontario (3). In a 1999 survey of Armillaria spp. conducted in central and southern Ontario, A. mellea s. str. was found at four of 110 locations surveyed, two approximately 100 km west and southwest of Ottawa, one 15 km north of Belleville, and one on the Niagara Peninsula in the Balls Falls Conservation Area. At the Ottawa area sites, A. mellea s. str. was found on red oak (Quercus rubra L.) and beech (Fagus grandifolia Ehrh.) stumps. A. ostoyae (Romagn.) Herink and A. gallica Marxmuller & Romagn. were also found on these sites. At the Belleville site, it was found on a dead co-dominant white birch (Betula papyrifera Marsh.), while at the Niagara Peninsula site it was found on a dead, suppressed beech. A. gallica was also found at these latter sites. Sites ranged from moisture regimes fresh to moist, and from sandy to silty soil from both calcareous and non-calcareous parent material. Four isolates were obtained from infected wood and rhizomorphs and identified by the polymerase chain reaction, yielding restriction fragment length polymorphism (RFLP) products of 500 and 183 base pairs. These fragment sizes are similar to findings reported in an earlier study (4). The identification was confirmed by haploid/diploid pairing. The Balls Falls Conservation Area is in close proximity to extensive fruit orchards and the presence of A. mellea is cause for concern, especially in light of its proven pathogenicity to fruit trees (1). This is the first confirmation of A. mellea s. str. in Ontario. References: (1) J. E. Adaskaveg and J. M. Ogawa. Plant Dis. 74:341–352, 1990. (2) J. T. Blodgett and J. J. Worrall. Plant Dis. 76:166–170, 1992. (3) M. T. Dumas. Can. J. For. Res. 18:872–874, 1988. (4) T. C. Harrington and B. D. Wingfield. Mycologia 87:280–288, 1995.
Molecular Identification of a Phytoplasma Associated with Witches'-Broom Disease of Black Raspberry in Oregon and Its Classification in Group 16SrIII, New Subgroup Q
Authors: Davis R. E. , Dally E. L. , Converse R. H. 
Published: May 2007

Plants of Rubus occidentalis (black raspberry) ‘Munger’ exhibiting symptoms of black raspberry witches'-broom (BRWB) disease were observed in commercial fields in Oregon (1). Symptoms were often severe, leading to death of infected plants, and a phytoplasma (mycoplasmalike bodies) was observed in ultrathin sections of diseased plants (1). In the current work, the association of phytoplasma with BRWB was assessed using the polymerase chain reaction (PCR) for specific amplification of phytoplasmal rDNA. DNA template for use in the PCR was extracted from plants as described elsewhere (2). Phytoplasmal 16S rDNA was amplified from diseased black raspberry plants in PCR primed by primer pair P1/P7 and reamplified in nested PCR primed by primer pair R16F2n/R2 (F2n/R2) by a method described previously (2). These results indicated the presence of a phytoplasma, designated BRWB phytoplasma, in the diseased plants. Identification of BRWB phytoplasma was accomplished by restriction fragment length polymorphism (RFLP) analysis of DNA amplified in PCR primed by F2n/R2. Phytoplasma classification was done according to the system of Lee et al. (3). On the basis of collective RFLP patterns of the amplified 16S rDNA, the BRWB phytoplasma was classified as a member of group 16SrIII (group III, X-disease phytoplasma group). The HhaI RFLP pattern of BRWB 16S rDNA differed from that of its close relative, clover yellow edge (CYE) phytoplasma. The RsaI RFLP pattern of BRWB rDNA differed from that of rDNA from all phytoplasmas previously described in group III. Based on these results, BRWB phytoplasma was classified in a new subgroup, designated subgroup Q (III-Q) within group III. The 1.8 kbp DNA product of PCR primed by primer pair P1/P7 was cloned and its nucleotide sequence determined. The sequence was deposited in GenBank under Accession no. AF302841. Results from putative restriction site analysis of the cloned and sequenced rDNA were in excellent agreement with the results from enzymatic RFLP analysis of uncloned rDNA amplified from BRWB diseased black raspberry. Sequence similarity between the 1.8 kbp rDNA of BRWB phytoplasma and that of CYE phytoplasma was 99.4%. The nucleotide sequence data support the conclusion that the BRWB phytoplasma is related to, but is distinct from, other strains that are classified in group III. These findings contribute knowledge about the diversity of phytoplasmas affiliated with group III and provide information to aid the diagnosis of BRWB disease. References: (1) R. H. Converse et al. Plant Dis. 66:949, 1982. (2) R. Jomantiene et al. Int. J. Syst. Bacteriol. 48:269, 1998. (3) I.-M. Lee et al. Int. J. Syst. Bacteriol. 48:1153, 1998.
First Occurrence of Powdery Mildew Caused by Leveillula taurica on Pepper in New York
Authors: McGrath M. T. , Shishkoff N. , Bornt C. , Moyer D. D. 
Published: May 2007

Powdery mildew was observed for the first time on pepper (Capsicum annuum L.) in western New York in August 1999 and on Long Island, NY, in August 2000. Infected plants were found in commercial fields planted with transplants from Georgia and Florida. Powdery mildew was not found in nearby commercial fields in either year, and it was not found in 2000 in western New York. Symptoms included white sporulation on the undersurfaces of leaves, causing yellow lesions on upper surfaces that turned necrotic and led to premature defoliation. The pathogen was confirmed to be Leveillula taurica (Lév.) G. Arnaud, a species complex that infects more than 1,000 plant species in 74 families, including pepper, tomato and eggplant. Only the Oidiopsis stage was found. Conidia were 47.3 to 74.3 μm × 10.5 to 20.3 μm (average 64.0 × 16.8 μm (N = 71). Symptoms were observed on all cultivars of bell and chili pepper in the Long Island field but not on tomato (Lycopersicon esculentum) and eggplant (Solanum melongena var. esculentum) in adjacent rows. Powdery mildew of pepper was first observed in North America in 1971 in southwest Florida (1). Symptoms were found on field-grown peppers in Florida in April 2001 at the time that transplants were being produced for New York. Considering the latent period is 18 to 21 days and symptoms tend to be initially subtle, diseased seedlings could easily go undetected. This disease is a problem on tomatoes and peppers in California (2), Arizona, Utah, and Nevada. Powdery mildew of pepper was reported in Puerto Rico in 1992, in Idaho on greenhouse-grown pepper in 1998, in north-central Mexico in 1998, and in both Canada and Oklahoma on greenhouse-grown pepper in 1999. Powdery mildew of peppers has not been seen in Connecticut, Massachusetts, New Jersey, North Carolina, or Ohio. References: (1) C. H. Blazquez. Phytopathology 66:1155, 1976. (2) R. F. Smith et al. Calif. Agric. 53:40, 1999.
Outbreak of Tomato spotted wilt virus in Tomato in Kenya
Authors: Wangai A. W. , Mandal B. , Pappu H. R. , Kilonzo S. 
Published: May 2007

Tomato spotted wilt virus (TSWV) of the genus Tospovirus, family Bunyaviridae (1), causes an economically important virus disease in tomato in several parts of the world. The virus has a wide host range that includes numerous crops and weeds and is transmitted by at least seven species of thrips. Tomato crops in the Subukia, Bahati, and Kabazi areas of the Nakuru District in Kenya were affected by a disease suggestive of TSWV infection during the November 1999 to March 2000 tomato-growing season. Farmers reported up to 80% losses of their potential yields. Characteristic symptoms were noticed on fruits, especially when they were green. Distinct concentric rings on fruits, which later turned into brown, uneven ripening, were the most visible symptoms. Foliage did not develop pronounced symptoms, but mild bronzing was observed in a few cultivars. However, foliage senesced prematurely, starting with older leaves. Foliar symptoms were mistaken for blight infection, and as a result, excessive fungicides were applied that failed to manage the disease. To test for TSWV infection, tomato leaf samples collected from the fields were tested initially with a TSWV test kit (HortiTech, Horticulture Research International, Wellesbourne, UK), and the results were confirmed by double-antibody sandwich-enzyme-linked immunosorbent assay with antibodies from Agdia Inc. (Elkhart, IN). Further molecular characterization was done using reverse transcription-polymerase chain reaction (RT-PCR). Total RNA was extracted from symptomatic leaves of tomato cv. Money Maker using the RNeasy mini kit (Qiagen Inc., Valencia, CA). Using primers 5′ TTAAGC AAGTTCTGTGAG 3′ and 5′ ATGTCTAAGGTTAAGCTC 3′ specific to the nucleoprotein (N) gene of TSWV, the N gene was amplified by RT-PCR (2). A 777-bp product of the expected size was obtained from symptomatic plants, whereas no amplification was obtained from noninfected tomato. The PCR product was cloned into pGEM-T Easy (Promega, Madison, WI) and sequenced. A search of GenBank revealed a sequence identity of 95 to 99% with the N genes of known TSWV isolates. To our knowledge, this is the first report TSWV infection of tomato in Kenya. Considering its wide host range, future surveys should be directed toward estimating its incidence in tomato and other TSWV-susceptible crops, such as Irish potatoes, pepper, peanut (groundnut), beans, and a wide variety of ornamental cut flowers in Kenya. References: (1) J. W. Moyer. Tospoviruses (Bunyaviridae). Pages 1803–1807 in: Encyclopedia of Virology. A. Granoff and R. G. Webster, eds. Academic Press, San Diego, CA, 1999. (2) Jain et al. Plant Dis. 82:900, 1998.
Report of Leaf Spot of Spinach Caused by Stemphylium botryosum in Maryland and Delaware
Authors: Everts K. L. , Armentrout D. K. 
Published: May 2007

In October 2000, leaf spot symptoms were observed on spinach (Spinacia oleracea L. ‘Seven R’) at the University of Maryland Lower Eastern Shore Research and Education Center in Salisbury. In April 2001, a similar leaf spot disease was observed in two commercial spinach fields (cv. Vancouver) in Dorchester County, MD, and Sussex County, DE. Symptomatic plants occurred in foci, and overall disease incidence in the research and commercial fields was <10% of plants with lesions. However, low disease incidence may reduce the value of a spinach crop by requiring additional hand-sorting (fresh market) or lowering the grade (processing). Leaf spot lesions were small (0.2 to 0.7 cm), circular, tan, and papery and lacked visual signs of fungal infestation. Lesions resembled a new leaf spot of spinach reported in California (1) caused by Stemphylium botryosum Wallr. Plating surface-disinfested lesion margins on 0.25-strength potato dextrose agar consistently yielded S. botryosum. Single conidial cultures of three isolates were grown on V8 agar in a growth chamber with a 12 h light/dark regime at 21°C and were used for the pathogenicity test. Conidia were collected from 7-day-old colonies to test pathogenicity. Conidia were suspended in distilled water (1.1 × 105 conidia per milliliter), and sprayed on 4-week-old spinach plants (with four to six true leaves) of cvs. Seven R, Vancouver, and Melody. Noninoculated control plants were sprayed with deionized water. Plants were incubated for 72 h in a dew chamber (18°C, 9 to 15 h light/dark regime where dew formed during the dark periods) and then placed on a greenhouse bench (23°C) for 2 weeks. Plants that had been inoculated with any of the three isolates developed the aforementioned leaf spot lesions after 4 days in the greenhouse. Plants sprayed with deionized water were symptomless. One week after inoculation, more lesions were observed on ‘Seven R’ and ‘Vancouver’ than on ‘Melody’ (41, 39, and 1 lesion per plant, respectively; P< 0.0030), and the lesions were 1.5, 1.2, and 0.5 mm in diameter, respectively (P< 0.0001). S. botryosum was consistently reisolated from leaf spot lesions. The pathogenicity test was repeated with similar results. Isolates grown on V8 agar and incubated for ≈10 days produced conidia with mean dimensions of 31 × 19 μm. To our knowledge, this is the first report of leaf spot of spinach caused by S. botryosum in Maryland and Delaware. Reference: (1) S. T. Koike et al. Plant Dis. 85:126, 2001.