bluuebunny/crossref_metadata_2025_split huggingface dataset:
First Report of Zucchini yellow mosaic virus in Argentina
Authors: Gracia O. 
Published: May 2007

In August 1996, a severe viral disease occurred in squash produced in the subtropical Province of Salta, Argentina. Plants of Cucurbita pepo L. (zucchini) and Cucurbita maxima L. ‘Any’ were affected. Approximately 50% of the plants showed prominent yellow mosaic, necrosis, and foliar distortion. Most of the fruits on infected plants were small, with scattered glossy yellow knobs over a green background, and some showed additional fruit malformation. A potyvirus was isolated from infected plants by mechanical transmission. Filamentous particles were associated with symptomatic inoculated squash and cucumber plants in leaf-dip preparations with an electron microscope (Elmisckop I, Siemens, Germany). The particles were flexuous rods ≈755 nm long. The host range of the isolated virus was mostly limited to the cucurbits (systemic infection) but also included Gomphrena globosa (local and systemic symptoms) and Chenopodium quinoa and Chenopodium amaranticolor, which showed only local chlorotic lesions. Twenty species in the Compositae, Leguminosae, and Solanaceae were not infected (2). In agar double-diffusion tests with sodium dodecyl sulfate (SDS)-degraded virus particles, no reactions were observed with Papaya ringspot virus, Watermelon mosaic virus (WMV), and WMV-Mo antisera, but a strong precipitin line was obtained with the antiserum prepared by Purcifull (1) for isolate 1119 of Zucchini yellow mosaic virus (ZYMV). Isolate 1119 and our isolate appeared serologically indistinguishable in SDS immunodiffusion tests. Both gave fused precipitin bands without spur formation. The results (field symptoms, transmissibility, host range, particle morphology, and serology) lead to the conclusion that ZYMV is present in Argentina. Since 1996, outbreaks have occurred every year in Salta, devastating squash crops. In 1998, ZYMV also was found in the provinces of Mendoza and San Juan, infecting zucchini squash and melons (Cucumis melo L.). A survey of crops indicates that disease incidence and severity were lower than in Salta. References: (1) D. E. Purcifull et al. Plant Dis. 68:230, 1984. (2) H. L. Wang. Plant Dis. 76:530, 1992.
First Report of Alternaria alternata as a Dieback Pathogen of Kiwifruit
Authors: Tsahouridou P. C. , Thanassoulopoulos C. C. 
Published: May 2007

During a survey of diseases on kiwifruit (Actinidia chinensis) cv. Hayward during spring 1998 in Northern Greece, leaves of kiwifruit trees were found covered with small, necrotic brown spots. Intense spotting was associated with defoliation. Furthermore, small, sunken, dark brown cankers appeared a few centimeters below the twig tip, and twigs died distal to the canker a few days later, while the twig remained healthy below the canker, often producing a new shoot below the canker. Isolations from symptomatic leaves and internal tissues of twigs on potato dextrose agar (PDA), after surface-sterilization with 0.5% NaOCl and 90% alcohol, respectively, consistently yielded a fungus that, based on conidial morphological characteristics, was identified as Alternaria alternata (Nees:Fr.) Keissl. (2). Pathogenicity tests were performed on 3-year-old kiwi plants. Tests on twigs were conducted by inoculating 35 twigs with 5-mm disks from 7-day-old cultures on PDA at 25°C. Each twig was inoculated with three disks. Tests on leaves were conducted by spraying a conidial suspension (5 × 106 conidia per ml) of the cultures on leaves. Plants were kept in a glasshouse at 22 to 25°C. Symptoms, identical to those observed in the field, developed on leaves and twigs 6 and 18 days, respectively, after inoculation. All inoculated leaves exhibited symptoms of the disease, whereas more than 95% of inoculated twigs exhibited disease symptoms. A. alternata was consistently reisolated from inoculated tissues. A. alternata is widely known to be a leaf spot pathogen of kiwifruit (1). This is the first report of A. alternata causing twig dieback. References: (1) L. Corazza and L. Luongo. Plant Dis. 83:487, 1999. (2) E. G. Simmons. Mycotaxon 37:79, 1990.
First Report of Hemp Canker Caused by Sclerotinia sclerotiorum in Alberta, Canada
Authors: Bains P. S. , Bennypaul H. S. , Blade S. F. , Weeks C. 
Published: May 2007

Hemp (Cannabis sativa L.) is a herbaceous annual grown mainly for its blast fiber and seed oil. In 1999, Health Canada issued licenses to plant 12,145 ha of hemp in Canada. Of these, 730 ha were in Alberta. During the last week of August, hemp plants (cv. Fasamo) in a central Alberta field showed the following symptoms and signs: wilting foliage turning light brown; dry tan to gray lesions on stems; shredding and breaking of stems at the lesion; presence of white mycelium in the lesion; and black round, irregular, or oblong sclerotia (up to 5 mm diameter and 2 to 11 mm long) present externally at the lesion on the stem and inside the pith cavity. Lesions were found at the crown, near the inflorescence, and along the entire stem length. Disease incidence in a survey of six commercial fields (40 ha) ranged from 1 to 8%. The organism isolated from lesions on potato dextrose agar produced white aerial mycelia and large numbers of sclerotia characteristic of Sclerotinia sclerotiorum. Pathogenicity was confirmed by inoculating 23-day-old greenhouse-grown hemp plants (cv. Fasamo) with autoclaved wheat grains colonized for 14 days with a S. sclerotiorum culture previously isolated from an infected hemp plant. The grains were placed on soilless growing medium near the plant and covered very lightly. One week after inoculation, grayish lesions appeared on the stems, white mycelia appeared on lesions, and plants wilted. The pathogen was reisolated from the lesions. This is the first report of S. sclerotiorum on hemp in Alberta, Canada. The disease known as hemp canker has been reported to cause severe losses under cool wet conditions in the Netherlands (1). Reference: (1) J. M. McPartland. J. Int. Hemp Assoc. 3:19, 1996.
First Report of Hendersonula toruloidea as a Foliar Pathogen of Strawberry-tree (Arbutus unedo) in Europe
Authors: Tsahouridou P. C. , Thanassoulopoulos C. C. 
Published: May 2007

During spring 1997 and 1998 in the area of Chalkidiki, in northern Greece, leaves of wild strawberry-tree (Arbutus unedo) were heavily spotted. Small, necrotic brown spots with light gray centers appeared on leaves, and when intense spotting was present, strong defoliation was observed. Isolations from leaves on potato dextrose agar consistently yielded a fungus that was identified as Hendersonula toruloidea (2). Pathogenicity tests on wild strawberry-tree plants were performed, yielding symptoms identical to those originally observed, and H. toruloidea was isolated consistently from inoculated leaves. No cankers appeared on the twigs of the plants, which is a consistent symptom caused by this fungus on strawberry-tree in the United States. Leaf spotting caused by H. toruloidea has been observed in Musa and Rhus spp. (1). This is the first report of H. toruloidea causing leaf spotting and defoliation of strawberry-trees in Europe. References: (1) D. F. Farr et al. 1989. Fungi on Plants and Plant Products in the United States. The American Phytopathological Society, St. Paul, MN. (2) R. M. Nattrass. Br. Mycol. Soc. Trans. 18:189, 1945.
First Report of Tobacco streak virus in Strawberry in the Eastern United States
Authors: Hokanson S. C. , Martin R. R. , Maas J. L. 
Published: May 2007

In a 1998 virus survey (2) conducted on 23 commercial strawberry (Fragaria × ananassa Duchesne) production farms in the state of Maryland, leaf samples from 1,100 randomly sampled plants were sent to the U.S. Department of Agriculture laboratory in Corvallis, OR, for testing by enzyme-linked immunosorbant assays (ELISA). The viruses identified were Strawberry mild yellow edge, Strawberry crinkle, Strawberry veinbanding, Strawberry mottle, and Tomato ringspot viruses, all of which are known in the eastern United States. Tobacco streak virus (TSV) also was identified in 17 of the samples: 12 originated from a 1-year-old planting of ‘Sweet Charlie’ and 5 from another farm, of which 4 were from a 2-year-old ‘Sweet Charlie’ planting and 1 was from a 2-year-old ‘Delmarvel’ planting. Triple antibody sandwich ELISA was used to detect TSV following the procedures described by Finn and Martin (1), except that leaves from test plants were homogenized (1:20, wt/vol, in blocking buffer) and flat bottom microtiter plates (Nunc, Roskilde, Denmark) and goat anti-mouse (polyvalent) alkaline phosphatase conjugate were used in the assays. The absorbance of each well at 405 nm (A405) was read in an ELISA plate reader. Reactions were considered positive if the A405 values were greater than five times the values of healthy samples. The A405 values of healthy samples ranged from 0.0 to 0.04, with values greater than 0.20 considered positive for TSV. An independent determination of TSV was made in plants shipped from Florida to Maryland in 1999. In this instance, leaf samples from ‘Sweet Charlie’ plants were sent by the Maryland Department of Agriculture to Agdia Inc. (Elkhart, IN), where samples tested positive for TSV. References: (1) C. E. Finn and R. R. Martin. Plant Dis. 80:769, 1996. (2) S. C. Hokanson, et al. Adv. Strawberry Res. In press.
First Report of Phyllachora ambrosiae in Europe Causing Epidemics on Common Ragweed
Authors: Vajna L. , Bohár G. , Kiss L. 
Published: May 2007

Common ragweed (Ambrosia artemisiifolia var. elatior (L.) Descourt.) was introduced to Europe from North America during the nineteenth century. Since the early 1990s, it has become the most widespread and most important allergenic weed in Hungary. In July 1999, during the annual survey of fungal diseases of ragweed in Hungary, plants exhibiting irregular brown spots surrounded by yellowish halos with small black spherical bodies on the upper surface of leaves, especially along the vessels, were collected from three roadside sites. Light microscopy revealed intracellular hyphae in the cells of leaf tissues, including the vessels, and perithecia (186 to 262 μm in diameter) containing paraphyses and asci (93 × 15 μm) with eight hyaline, unicellular ascospores (14 × 7.5 μm). Hyphae also were observed in asymptomatic leaf tissues and the petioles of infected plants. Mature perithecia commonly found in the necrotic spots also were present in asymptomatic, green leaf tissues. Based on the literature (1,2) and on the morphological examination of two herbarium specimens, BPI 636220 and BPI 636225, borrowed from the U.S. National Fungus Collection, the fungus was identified as Phyllachora ambrosiae (Berk. & M.A. Curtis) Sacc., a holobiotrophic pathogen of ragweed in North and South America. This is the first report of P. ambrosiae on ragweed in Europe. To confirm pathogenicity, leaves of five potted ragweed plants, grown from seed in pots, were inoculated with 0.1 ml of an aqueous suspension containing 5 × 105 ascospores per ml. Inoculated plants were placed in a moist chamber for 48 h and kept in the greenhouse at 20 to 25°C. Noninoculated plants served as controls. Two weeks after inoculation, yellowish spots, which later became brown and necrotic, and perithecia appeared on each of the inoculated leaves. Infected leaves died 3 to 4 weeks after inoculation. Symptoms were similar to those seen in the field. The fungus in tissues of inoculated plants was morphologically identical to the original fungus on plants with spontaneous infections. Control plants did not develop symptoms. To determine the distribution of P. ambrosiae in Hungary, a total of 500 ragweed plants were collected at random from 21 locations in all regions of the country between August and October 1999. Symptoms characteristic of P. ambrosiae infections and perithecia of the fungus were found in 92% of all 500 collected plants. From mid-September, all ragweed plants examined had dead leaves and inflorescences. Perithecia of P. ambrosiae were found in leaves, stems, and flowers. References: (1) P. A. Saccardo. 1883. Sylloge Fungorum. Patavii (Padova), Sumptibus Aucteris. (2) F. Theissen and H. Sydow. 1915. Ann. Mycol. 13:431.
Occurrence of a New Pathotype of Lettuce mosaic virus on Lettuce in Brazil
Authors: Stangarlin O. , Pavan M. A. , da Silva N. 
Published: May 2007

Since 1970 lettuce mosaic has not been an important disease of lettuce in Brazil, due to the growing of cultivars that contain gene g, derived from cv. Gallega de Invierno, for tolerance. Recently, however, a widespread, serious outbreak of lettuce mosaic occurred in the State of Sao Paulo. Both lettuce cultivars that lack and those that contain gene g have been affected, suggesting the emergence of a new pathotype of Lettuce mosaic virus (LMV). Commercial lettuce fields were visited, and 20 samples were collected for virus identification by bioassay on differential hosts, serological tests, and electron microscopy. Of these, 12 were infected only by LMV, and 8 contained mixed infections of LMV and a possible new sequivirus, Lettuce mottle virus. Seedlings of susceptible cv. White Boston were inoculated with LMV from tolerant cultivars, and plants were allowed to flower. Seeds were collected and sown, and seedlings with mosaic symptoms were recovered. Twenty monolesional isolates, obtained by passing the virus three times through Chenopodium amaranticolor, were inoculated individually on lettuce differential cvs. Salinas and White Boston (susceptible) and cvs. Salinas 88, Vanguard 75, Ithaca, Malika, and Gallega de Invierno (tolerant) to previously described pathotypes of LMV (1). Considering the susceptibility of all test differentials, we concluded that a LMV pathotype IV exists that has overcome tolerance conferred by genes m and g and is responsible for the new outbreak of LMV in Brazil. This is the first report of LMV-IV in Latin America. Reference: (1) D. A. C. Pink et al. Plant Pathol. 41:5, 1992.
First Report of Gray Leaf Spot on Perennial Ryegrass in Indiana
Authors: Harmon P. , Rane K. , Ruhl G. , Latin R. 
Published: May 2007

Pyricularia grisea, the causal agent of gray leaf spot on turfgrass, was isolated from symptomatic perennial ryegrass (Lolium perenne) leaves collected from a golf course in north-central Indiana in August 1999. Gray leaf spot is an emerging threat to stands of perennial ryegrass in the mid-Atlantic and Midwestern United States (1). Symptoms were first evident in taller (6 cm) mown, rough areas surrounding golf course fairways. Field symptoms included diffuse patches (1 to 4 m in diameter) of thin, yellow-tan turf. Within larger affected areas, some of the turf was dead and matted. Close inspection revealed the presence of typical tan-gray lesions with brown margins and fish hook-like distortion of infected leaf blade tips. Incubation of affected turf in a saturated environment at 23°C for 16 h resulted in production of numerous three-celled, pear-shaped conidia characteristic of those produced by P. grisea. A pure culture of the isolate was grown on V8-juice agar in darkness at 29°C. After 10 days, the culture was exposed to continuous light for 4 days at 23°C to induce sporulation. Conidia were washed from the colony surface with sterile distilled water. Two-week-old perennial ryegrass plants in 8-cm-diameter pots were inoculated with the conidial suspension. Typical gray leaf spot symptoms resulted after incubation of inoculated plants at 27°C for 72 h in a saturated atmosphere. Uninoculated control plants exposed to the same environmental conditions remained healthy. This is the first report of gray leaf spot on perennial ryegrass in Indiana. Reference: (1) P. J. Landschoot and B. F. Hoyland. Plant Dis. 76:1280, 1992.
First Report of Armillaria mellea on a Fern from Italy
Authors: Grasso S. , Pane A. , Cacciola S. O. 
Published: May 2007

Several perennial species of rhizomatous herbaceous ferns are cultivated as ornamental foliage plants. During late summer 1999, in a garden at the foot of Mount Etna, eastern Sicily (Italy), we noted a fern hedge showing patches of withered or stunted plants. The fern was identified as Cyrtomium falcatum (L.f.) C. Presl. (=Polystichum falcatum (L.f.) Diels), a house holly fern or Japanese holly fern, which is an ornamental fern native to East and South Asia. Other woody plants in the immediate vicinity had died over the last few years, including apricot and cedar trees whose stumps had not been removed. A close examination of uprooted ferns revealed the presence of creamy white fan-shaped mycelial mats with an odor typical of Armillaria species that were intermixed with the felt-like tangle formed by the rhizomes and roots of the ferns. In autumn, clumps of honey mushrooms with an annulus grew around patches of the withered fern hedge and in other parts of the same garden. The spore print of the basidiocarp was light cream. Basidiospores (8 to 9 × 5 to 6.5 µm) examined under a microscope were hyaline and apiculate. The fungus was isolated in pure culture from infected rhizomes with the selective medium of Kulman and Hendrix (3). In pure culture on 2% malt agar, the fungus formed ribbon-shaped, contorted, fast-growing rhizomorphs that branched profusely. Mycelial proteins of the isolate were analyzed by both polyacrylamide slab gel and starch gel electrophoreses, as described by Bragaloni et al. (1). The electrophoretic patterns of five isozymes (esterase, glutamic oxalacetic transaminase, phospho-glucomutase, alcohol dehydrogenase, and polygalacturonase) of the isolate from fern were identical to those of the reference isolate of A. mellea (Vahl:Fr.) Kumm. from grapevine. Conversely, the patterns were clearly distinct from those of reference isolates from other species, including A. ostoyae (Romagnesi) Herink, A. bulbosa (Barla) Kile et Watling, and A. cepistipes Velenovsky. Thus, on the basis of cultural, morphological, and biochemical characteristics, the species infecting the fern was identified as A. mellea. This pathogen, very common and widespread on wooded or previously wooded sites, has an extremely wide host range, encompassing both woody and herbaceous plants (2,4). However, this is the first report of A. mellea on a fern in Italy. References: (1) M. Bragaloni and N. Anselmi. Eur. J. For. Pathol. 27:147, 1997. (2) D. F. Farr et al. 1989. Fungi on Plants and Plants Products in the United States. The American Phytopathological Society, St. Paul, MN. (3) E. G. Kulman and F. F. Hendrix. Phytopathology 52:1310, 1962. (4) C. G. Shaw and G. A. Kile. 1991 Armillaria root disease. Agric. Handb. No 691. U.S. Department of Agriculture Forest Service, Washington, DC.
Detection of a Whitefly-Transmitted Geminivirus in Launaea spp. in India
Authors: Raj S. K. , Chandra G. , Singh B. P. 
Published: May 2007

Launaea acaulis (Roxb.) Babc. Aerr. and L. procumbeus (Roxb.) Ramayya & Rajgopal are weeds that grow near agricultural fields in India during the rainy season. Yellow net symptoms were observed in both species, but not in crops, in 1998 and 1999. Nicotiana tabacum cv. White Burley developed leaf curl symptoms after virus transmission from L. acaulis by whiteflies (Bemisia tabaci). Thus, the involvement of a geminivirus was suspected. Total DNA from infected and uninfected tobacco and Launaea plants was extracted by the cetyl trimethyl ammonium bromide method and precipitated by ethanol. Polymerase chain reaction (PCR), using DNA from infected and uninfected plants as a template and degenerate oli-gonucleotide primers designed from DNA-A of whitefly-transmitted African cassava mosaic virus (ACMV) (1) was performed. An expected ≈500-bp fragment was observed after agarose gel electrophoresis of the PCR product. Total DNA from infected plants gave positive signals and was homologous with the probe from cloned DNA-A of Indian tomato leaf curl virus (2) in high-stringency Southern hybridization tests. No PCR amplification and positive signals were obtained from DNA from uninfected plants. PCR amplification of the 500-bp fragment with primers from DNA-A of whitefly-transmitted ACMV resulted in positive signals, and homology with the probe indicated that L. acaulis and L. procumbens harbor whitefly-transmitted geminivirus infections. This is the first report of geminivirus infection in these Launaea spp. in India. References: (1) D. Deng et al. Ann. Appl. Biol. 125:327, 1994. (2) K. M. Srivastava, et al. J. Virol. Methods 51:297, 1985.
First Report of Alfalfa mosaic virus in Pachysandra terminalis in Europe
Authors: Cardin L. , Moury B. 
Published: May 2007

Pachysandra terminalis (Buxaceae) was introduced from Japan to Europe in 1882. This ornamental plant is grown in northern Europe as a ground cover in shaded sites. Line patterns, more or less necrotic ringspots, and mosaic symptoms on leaves of pachysandra plants have been seen in public gardens in France (Strasbourg, Colmar, Mulhouse, and Nantes) and Germany (Freiburg im Breisgaü). Extracts of plant tissues obtained from these five sites were used for mechanical- and aphid-transmission experiments, enzyme-linked immunosorbent assays (ELISA) with antibodies directed toward a tomato strain of Alfalfa mosaic virus (AMV) (from G. Marchoux, INRA, France), and electron microscopy. All inoculations produced symptoms typical for AMV in Nicotiana tabacum cv. Xanthi-nc tobacco, Chenopodium amaranticolor, C. quinoa, Vigna unguiculata, Phaseolus vulgaris, Vicia faba, Pisum sativum, and Ocimum basilicum (2). Moreover, Medicago arborea, a new host for AMV, showed systemic mosaic on leaflets. On these and the original pachysandras, AMV was readily detected by ELISA. After isolation from three to four local lesions on Vigna unguiculata and further multiplication in tobacco, one isolate was purified. Bacilliform particles of three sizes, typical for AMV, were seen by electron microscopy. Transmissions of the strain to ELISA-negative pachysandras was achieved by mechanical inoculations (7 of 20 inoculated plants were ELISA positive) and by the aphid species Myzus persicae and Aphis craccivora (14 of 17 inoculated plants were infected). Symptoms were observed 2 months after inoculation; some of the plants remained symptomless but were AMV positive in ELISA. As early as 1970, similar symptoms were reported in pachysandra in New Jersey, and AMV was isolated from affected plants (1). However, inoculations of healthy pachysandra plants with AMV was not performed. Our results show the need for an AMV indexing protocol in the propagation of pachysandra to control its spread. References: (1) D. E. Hershman and E. H. Varney. Plant Dis. 66:1195, 1982. (2) E. M. J. Jaspars and L. Bos. 1980. Alfalfa mosaic virus. No. 229 in: Descriptions of Plant Viruses. Commonw. Mycol. Inst./Assoc. Appl. Biol., Kew, England.