bluuebunny/crossref_metadata_2025_split huggingface dataset:
First Report of a Geminivirus Inducing Yellow Mottle in Okra (Abelmoschus esculentus) in Mexico
Authors: De La Torre-Almaráz R. , Monsalvo-Reyes A. C. , Rivera-Bustamante R. F. , Méndez-Lozano J. 
Published: May 2007

Okra is an annual vegetable species native to Africa. In Mexico, the states of Tamaulipas, Guerrero, and Morelos contain the most important okra-producing areas. Viral-like diseases have recently affected the fruit production. In the field, the most common symptoms encountered include yellow streak, distortion of fruits, and foliar yellow mottle. Total DNA extracts from symptomatic okra plants were used as a template for polymerase chain reaction (PCR)-based detection using begomovirus-specific primers. RepMot and CPMot primers (1) were used for the amplification of DNA fragments that included the Rep and coat protein (CP) genes of begomoviruses. PCR results suggested the presence of a begomovirus in symptomatic plants. Southern and dot blot hybridization analysis were performed using a DNA fragment containing the CP gene of Pepper huasteco virus as a probe. Hybridization conducted under low stringency conditions confirmed the presence of a geminivirus. Additionally, transmission by grafting and biolistic (total DNA extracts from symptomatic plants) inoculations induced consistently severe streak fruits and yellow mottle symptoms in okra plants. Cloning of the PCR products (approximately 632-bp fragment) was performed in the PCRTopo vector (Invitrogen, San Diego, CA). Cloned viral inserts were sequenced (Genbank Accession No. AF349113). Nucleotide sequence comparisons were performed using the Clustal Method (MegAlign, DNAStar software, Madison, WI) with the GenBank database. Analysis of the PCR products confirmed the begomovirus nature of the sequence. The first 64 amino acids of the CP had 89% identity with Squash leaf curl virus while the intergenic region had 85% identity with Sida golden mosaic virus. To our knowledge, this is the first report of a begomovirus infecting okra in Mexico. Reference: 1) J. T. Ascencio et al. Plant Dis. 86:692, 2002.
First Report of Septoria Leaf Spot on Cornus sericea in Italy
Authors: Garibaldi A. , Bertetti D. , Gullino M. L. 
Published: May 2007

Cornus sericea (synonym C. stolonifera), family Cornaceae, is becoming widely used in Italy as ground cover in parks and gardens. In spring 2001, severe outbreaks of a previously unknown disease were observed in several gardens located in northern Italy (Biella Province). Infected leaves displayed small, circular, angular, or irregular necrotic lesions measuring 1 to 3 mm in diameter. Lesions were olivaceous to dark brown with a distinct reddish-to-black margin and surrounded by a chlorotic halo. Lesions eventually coalesced. Under favorable conditions, infected leaves become heavily spotted, dulling their appearance; severe infections resulted in premature defoliation. Pycnidia occurred on diseased leaves, and a fungus identified as Septoria cornicola (1) was consistently isolated on potato dextrose agar (PDA). Dark mycelium grew slowly on PDA and produced abundant pycnidia and conidia. Conidia were holoblastic, hyaline, 2 to 6 septate, 22 to 48 µm (average 35) × 2.2 to 3.6 µm (average 2.5). Pathogenicity tests were performed by inoculating leaves of healthy plants of C. sericea (cv. Flaviramea) with a conidial suspension (1 × 106 CFU/ml). Noninoculated plants served as controls. Plants were covered for 72 h with plastic bags and maintained in a growth chamber at 20°C. The first lesions developed on leaves of inoculated plants after 15 days. From such lesions, S. cornicola was consistently reisolated. No symptoms occurred on control plants. The presence of S. cornicola on C. sericea cv. Flaviramea has been reported in the United States (2) and was observed in 1905 in northeastern Italy on Cornus sanguinea (1), but to our knowledge, this is the first report of septoria leaf spot on C. sericea in Italy. References: (1) D. F. Farr. Mycologia, 83:611, 1991. (2) D. Neely and D. S. Nolte. J. Arboric. 15:263, 1989.
First Report of Root Rot on Asparagus Caused by Phytophthora megasperma in Canada
Authors: Vujanovic V. , Hamel C. , Jabaji-Hare S. , St-Arnaud M. 
Published: May 2007

In August 2002, Phytophthora megasperma Drechs. was isolated from wilted plants of Asparagus officinalis L. cv. Guelph Millenium displaying spear and crown rot. Six affected plants were sampled in a commercial asparagus field located in the Saguenay-Lac-Saint-Jean Region (300 km northeast of Montreal, Quebec, Canada). The fungus was isolated from asparagus fern stalks, crown tissue, and spears after a rainy period and identified using morphological and cultural characteristics (2). In pinkish 4-week-old cultures, unbranched stalks bore abundant sporangia, which were ovoid to obpyriform in shape, 15 to 45 m long, and 10 to 30 m in diameter. Characteristic circular oospores >30 m in diameter were produced on V8 juice agar at 25°C in darkness after 1 month. Pathogenicity was tested on asparagus cvs. Guelph Millenium and Jersey Knight. A mycelium suspension (3 ml at 106 CFU/ml) prepared from 1-week-old shaken potato dextrose (PD) broth was sprayed on 30 1-week-old seedlings grown in petri plates filled with sterilized, moist, sandy soil and held at 20°C (day/night). Controls received sterile PD broth. Within 3 weeks of incubation in the dark, inoculated seedlings exhibited necrotic symptoms similar to those observed initially, while controls remained healthy. The pathogen was isolated from 75% of the ‘Guelph Millenium’ and 98% of the ‘Jersey Knight’ symptomatic seedlings, but not isolated from the control seedlings. In North America, disease caused by P. megasperma resulting in yield loss has been reported in California and New York (1,3). In Canada, the etiology of asparagus diseases is not well characterized. To our knowledge, this is the first report of P. megasperma on asparagus plants in Canada. References: (1) P. A. Ark and J. T. Barrett. Phytopathology 28:754, 1938. (2) D. C. Erwin et al. Phytophthora: Its Biology, Taxonomy, Ecology, and Pathology. The American Phytopathological Society, St Paul, MN, 1983. (3) T-L. Kuan and D. C. Erwin. Phytopathology 70:333, 1980.
Occurrence of Pseudoperonospora cubensis Pathotype 5 on Squash in Italy
Authors: Cappelli C. , Buonaurio R. , Stravato V. M. 
Published: May 2007

During the period of May to August 2002, typical symptoms of downy mildew were observed on squash (Cucurbita pepo L.) in both tunnel and open field cultivation in central Italy (Latium and Umbria). The disease spread rapidly and because the control measures used were not effective, growers suffered severe yield losses. Infected plants showed yellow spots on the upper leaf surface. Based on morphological features observed at ×10 to ×40 magnification, the pathogen was identified as Pseudoperonospora cubensis (Berk. & M.A. Curtis) Rostovzev. To verify the pathogenicity of the fungus, a sporangial suspension (1 × 104 sporangia per ml) was sprayed on leaves of squash plants with two expanded leaves, which were held in dark moist chambers at 20 ± 2°C for 48 h. Control plants were sprayed with sterile water. Inoculated and control plants were kept in a growth chamber at 24 ± 2°C with 14/10 h day/night cycles. Chlorotic spots and sporulation were observed on inoculated plants. The morphological features of the fungus obtained from the inoculated plants were identical to those from the original diseased plant. Previous observations of downy mildew in Italy suggested that squash was not susceptible (1). The physiological specialization among isolates of P. cubensis based on the compatibility of different cucurbit hosts (2) was not tested previously in Italy. To determine the pathotype of four fungal isolates obtained from squash cultivated in different localities, 10 plants per species of the cucurbit species (2) were inoculated with each isolate using the same procedure described for the pathogenicity test. Disease symptoms were detected on all inoculated hosts, including squash, suggesting that all the fungal isolates obtained from squash are pathotype 5. Only pathotype 5 is a common causal agent of downy mildew of squash and other cucurbit hosts. During the period of our observations, climatic conditions were unusually wet because frequent storms occurred during the summer providing favorable environmental conditions for the development of secondary spread. Today, it appears there are no commercially acceptable cultivars of squash resistant to downy mildew available to growers in Italy. References: (1) F. Ciccarese et al. Phytopathol. Mediterr. 29:14, 1990. (2) C. E. Thomas et al. Phytopathology 77:1621, 1987.
First Report of Powdery Mildew (Microsphaera palczewskii) on Siberian Pea Tree (Caragana arborescens) in North America
Authors: Nischwitz C. , Newcombe G. 
Published: May 2007

Caragana arborescens Lam. is an exotic ornamental that can also be somewhat invasive. In July 2002, powdery mildew was observed on C. arborescens along the Idaho-Washington border in Moscow and Pullman, respectively. Leaves were colonized as soon as they emerged, and entire plants were affected. The fungus covered both leaf surfaces, but cleistothecia were more abundant on abaxial surfaces. The mean diameter of the cleistothecia was 91 (± 9.8) μm. Short-stalked asci averaged 67 (± 7.1) μm × 37 (± 5.2) μm, and the ascospores were 21 (± 2.0) μm × 13 (± 0.8) μm. There are records of four species of Microsphaera on C. arborescens in Europe and Asia. The measurements fit the description of Microsphaera palczewskii Jacz. (1), and the identification was confirmed by comparison with specimens of this fungus on C. arborescens from Sweden (U.S. National Fungus Collections: BPI 749057 and 749058). Specimens of M. grossulariae (Wallr. ex Fr.) Lev. on Ribes divaricatum Dougl. from California (BPI 558266) were also examined, but the cleistothecial appendages were distinctly different from those of the Idaho specimens. To our knowledge, this is the first reported occurrence in North America of powdery mildew on C. arborescens and the first report of M. palczewskii. The latter may have been introduced recently into North America because there are areas in southern Canada and the northern United States in which C. arborescens is unaffected by powdery mildew. Interestingly, it is only in recent decades that M. palczewskii has spread from Asia into Europe (2). Now, host and parasite have been reunited in North America as well. Specimens have been deposited in the U.S. National Fungus Collections (BPI). References: (1) U. Braun. A monograph of the Erysiphales (powdery mildews) J. Cramer, Berlin-Stuttgarg, 1987. (2) S. Huhtinen et al. Karstenia 41:31, 2001.
First Report of Phytophthora cinnamomi on High-Bush Blueberry in Italy
Authors: Tamietti G. 
Published: May 2007

Beginning in the summer of 1996, a disease of high-bush blueberry (Vaccinium corymbosum L.) appeared on cvs. Sparta and Berkeley in commercial plantings near Cuneo and in a nursery in Pinerolo (northwest Italy). In the field, the disease became evident 5 to 8 months after planting. Symptoms included stunting, pale green-to-reddish leaves, premature defoliation, and root and crown rot. The root system was reduced, with few feeder roots and a dark discoloration of the root cortex. Root, crown, and basal stem rot led to death of the plants. Pieces of the discolored organs were surface-sterilized in sodium hypochlorite (2%) for 5 min, rinsed in sterile water, dried on sterile filter paper, and plated on acidified malt extract agar (pH 4.6) (MEA) and a selective medium for oomycetes (2). Slow-growing colonies developed on MEA, whereas colonies characteristic of Phytophthora spp. grew on the selective medium for oomycetes. Six isolates from plants collected from the field and the nursery were inoculated as V8 juice culture homogenate on the roots of blueberry cv. Berkeley, azalea, and 1-year-old chestnut plants in pots. All six isolates reproduced the symptoms in blueberry and caused root and foot rot in the other hosts. The original fungus was reisolated from all inoculated hosts. The isolates were examined and compared with strain 0229 of P. cinnamomi Rands from the International Mycological Institute. They were identified as P. cinnamomi on the basis of morphological characteristics and total mycelial soluble protein patterns on sodium dodecyl sulfate-polyacrylamide gel electrophoresis. In Italy, blueberry is a new host for this pathogen that was previously observed in rhododendron (1), and recently in chestnut (3) and other forest species. Because of the high risk of spreading the pathogen to areas where susceptible plants are grown, it is recommended that high-bush blueberry nursery stock be tested for the pathogen. References: (1) G. Gullino and A. Garibaldi. La difesa delle piante 10:273, 1987; (2) H. Masago et al. Phytopathology 67:425, 1977. (3) A. M. Vettraino et al. Plant Pathol. 50:90, 2001.
First Report of Cucurbit yellow stunting disorder virus in Commercial Cucumber Greenhouses in France
Authors: Desbiez C. , Lecoq H. , Girard M. , Cotillon A. C. , Schoen L. 
Published: May 2007

In autumn 2001, severe yellowing symptoms were observed on greenhouse-grown cucumbers near Perpignan (southern France). Leaf samples were collected from two sites where plants displayed symptoms ranging from limited yellowing of the older leaves to severe, complete yellowing of the whole plant. Cucurbit aphid-borne yellows virus, a polerovirus that causes similar symptoms was not detected in doubleantibody sandwich enzyme-linked immunosorbent assay (DAS-ELISA) using a specific antiserum. Total RNA was extracted from fresh leaf tissues and used in reverse transcription-polymerase chain reaction (1) with primers specific for two whitefly-borne viruses also inducing yellows and occurring in the Mediterranean basin (1): Beet pseudo yellows virus (BPYV, genus Closterovirus) transmitted by Trialeurodes vaporariorum (West.) and Cucurbit yellow stunting disorder virus (CYSDV, genus Crinivirus) transmitted by Bemisia tabaci (Genn.). No BPYV was detected in this survey, but CYSDV was present in all samples. In subsequent surveys conducted in the spring and summer of 2002, BPYV and CYSDV were detected, sometimes in mixed infections, in samples collected from the same region. The complete CYSDV coat protein gene was amplified by PCR using specific primers (2), yielding the expected-size fragment of 756 bp. The French isolate (GenBank Accession No. AY204220) shared 99.6 to 100% nucleotide sequence identity in the sequenced CP fragments (700 nt) with isolates of the most common, highly homogenous subgroup of CYSDV that has emerged recently in the Middle East, southwestern Europe (Spain and Portugal), United States, and Morocco (2). To our knowledge, this is the first report of CYSDV in France and it shows the threat represented by the current emergence of B. tabaci-transmitted viruses. References: (1) I. C. Livieratos et al. Plant Pathol. 47:362, 1998. (2) L. Rubio et al. J. Gen. Virol. 82:929, 2001.
First Report of a Leaf Blight of Onion Caused by Xanthomonas spp. in Georgia
Authors: Sanders F. H. , Langston D. B. , Brock J. H. , Gitaitis R. D. , Curry D. E. , Torrance R. L. 
Published: May 2007

In October of 2001 and 2002, a leaf blight was reported affecting Vidalia onion (Allium cepa) cvs. Pegasus and Sweet Vidalia, respectively, in one field each. Lesions on onion seedlings began as a water-soaked, tip dieback that gradually blighted the entire leaf. Symptoms on onion transplants appeared as elongated, water-soaked lesions that typically collapsed at the point of initial infection. In both cases, disease was very severe on seedlings, and disease incidence was 50% or more in both fields. Warm temperatures combined with overhead irrigation and above average rainfall likely enhanced the severity and spread of disease. Disease was not detected on more mature onions once cool, dry conditions occurred later in the season, and no significant economic loss occurred. Seed was tested from seed lots of the aforementioned cultivars and Xanthomonas spp. were not found. Diseased tissue was macerated in sterile, phosphate-buffered saline, and 10 μl of the resulting suspension was streaked on nutrient agar plates. Yellow-pigmented, gram-negative, rod-shaped bacteria were isolated routinely from diseased tissue. Bacteria were catalase-positive, cellulolytic, oxidase-negative, amylolytic, proteolytic, and utilized glucose in an oxidative manner. Analysis of whole cell, fatty acid methyl esters (FAME) using the Microbial Identification System (MIS, Sherlock version 3.1; MIDI, Inc., Newark, DE) identified four representative strains of the bacterium as a pathovar of Xanthomonas axonopodis (similarity indices 0.75 to 0.83). Known Xanthomonas spp. from onion from Colorado and Texas (1,2) had similar FAME profiles when analyzed by the MIDI system. Onion plants were grown under greenhouse conditions for 2 months and inoculated by injecting the base of a quill with 1.0 ml of bacterial suspensions (1 × 107 CFU ml-1) of the Xanthomonas sp. isolated from Georgia, and negative controls were inoculated with 1 ml of sterile water. Disease symptoms developed on plants inoculated with bacterial suspensions in 4 to 7 days and Xanthomonas sp. was isolated from the lesions produced. Disease symptoms occurred when the same suspension was sprayed on onion foliage. No symptoms occurred on plants inoculated with 1 ml of sterile water. To our knowledge, this is the first report of Xanthomonas spp. affecting Vidalia onions. References: (1) T. Isakeit et al. Plant Dis. 84:201, 2000. (2) H. F. Schwartz and K. Otto. Plant Dis. 84:922, 2000.
First Report of Anthracnose of Gaultheria procumbens Caused by Colletotrichum gloeosporioides
Authors: Elmhirst J. F. , Hudgins E. J. 
Published: May 2007

In 2001, a stem canker and dieback associated with a Colletotrichum sp. was observed on Gaultheria procumbens L. (wintergreen) seedlings grown from seed in soilless potting mix at four commercial nurseries in coastal British Columbia, Canada. Black, water-soaked lesions developed into tan cankers girdling stems and petioles, and a black rot extended into the base of leaves. In 2002, a Colletotrichum sp. was isolated from similar stem cankers from wintergreen plants. One flat of healthy, 13-week-old seedlings of G. procumbens (one- to three-leaf stage; approximately 380 seedlings per flat) was inoculated with a mycelial and spore suspension of one of the Colletotrichum sp. isolates at 108 CFU/ml using a hand atomizer. The flat was covered with black plastic for 24 h after inoculation and maintained in a growth chamber at 22°C with overhead watering. After 7 days, 98% of seedlings in the inoculated flat were necrotic with abundant sporulation of the Colletotrichum fungus on stem and petiole lesions. Plants in noninoculated flats remained healthy. Reisolation of the fungus from symptomatic tissues confirmed the causal agent to be Colletotrichum gloeosporioides (Penz.) Penz. & Sacc. in Penz, based on morphology (1,2) and polymerase chain reaction (PCR) using the species-specific primer CgInt (3). Cylindrical, hyaline, aseptate conidia measuring 16 to 20 × 4 to 6 μm were produced in acervuli with setae. Perithecia of the teleomorph, Glomerella cingulata, observed on the plants and in culture, measured 100 to 128 μm in diameter and contained acsi measuring 56 to 60 × 8 to 10 μm. Ascospores were hyaline, unicellular, slightly curved, and measured 18 to 20 × 4 to 6 μm. Subsequently, a single-spore isolate of the fungus was used to inoculate 21-week-old seedlings in the greenhouse as described above. Four inoculated and four noninoculated half-flats containing an average of 160 seedlings each were randomized on the greenhouse bench and maintained at 22°C with daily overhead misting. Stem and petiole cankers appeared on 65.1% of inoculated seedlings at 10 days after inoculation (mean of four inoculated half-flats); increasing to 90.5% at 14 days. At 14 days, 5.9% of seedlings in four noninoculated half-flats were also symptomatic, possibly from spore contamination as a result of overhead watering. To our knowledge, this is the first confirmation of the causal agent of wintergreen seedling death in seed propagation nurseries in British Columbia. References: (1) J. E. M. Mordue. Glomerella cingulata. No. 315 in: Descriptions of Pathogenic Fungi and Bacteria. CMI, Kew, Surrey, UK, 1971. (2) B. C. Sutton. The Coelomycetes. CAB International Publishing, New York, 1980. (3) P. Talhinhas et al. Phytopathology 92:986, 2002.
First Report of Meloidogyne incognita Infecting Spinach in Southern Spain
Authors: Castillo P. , Jiménez-Díaz R. M. 
Published: May 2007

Severe plant yellowing and decline were recently observed in two commercial fields of spinach (Spinacia oleracea cv. Polka) in Encinarejo (Córdoba), southern Spain. Disease surveys revealed severe infections of main and feeder roots and a large soil population of the southern root-knot nematode Meloidogyne incognita. The nematode population was extracted and quantified from soil and root samples according to Barker (1) and identified by female perineal pattern, phenotype esterases, and host-differential test (3,4). M. incognita was found in 100% of soil samples and 85.7% of root samples with nematode population densities ranging from 44 to 378 eggs and second-stage juveniles (J2s) per 100 cm3 of soil and 162 to 725 eggs and J2s per 5 g of fresh roots. Infected roots showed large, regular galls on root tips and also along the main root axis and secondary feeder roots. Galling of root tips prevents further root growth into deeper soil layers and induced proliferation of secondary roots. The severe infections in roots of spinach suggest that parasitism of spinach roots by the nematode must contribute to stunting, yellowing, and decline of spinach as previously reported (2). To our knowledge, this is the first report of M. incognita infecting spinach in Spain. References: (1) K. R. Barker. Nematode extraction and bioassays. Page 19 in: An Advanced Treatise on Meloidogyne. Vol. II, Methodology. K. R. Barker, C. C. Carter, and J. N. Sasser, eds. North Carolina State University Graphics, Raleigh, 1985. (2) J. C. Correll et al. Plant Dis. 78:653, 1994. (3) P. R. Esbenshade and A. C. Triantaphyllou. J. Nematol. 22:10, 1990. (4) K. M. Hartman and J. N. Sasser. Identification of Meloidogyne species on the basis of differential host test and perineal pattern. Page 69 in: An Advanced Treatise on Meloidogyne. Vol. II, Methodology. K. R. Barker, C. C. Carter, and J. N. Sasser, eds. North Carolina State University Graphics, Raleigh, 1985.