bluuebunny/crossref_metadata_2025_split huggingface dataset:
First Report of Powdery Mildew (Sawadaea bicornis) on Norway Maple (Acer platanoides) in North America
Authors: Nischwitz C. , Newcombe G. 
Published: May 2007

Norway maple (Acer platanoides L.) was introduced into the continental United States around 1756 as a street tree (2). It is a widely planted shade tree in the northern United States and Canada due to its fast growth rate when young and its tolerance of pavement and dry soils. Powdery mildew is common on Norway maple in Europe with records from at least 22 countries according to the databases of the U.S. National Fungus Collections. However, there are no North American records. In September 2002, powdery mildew was observed on young Norway maple trees along the Idaho-Washington border in Moscow and Pullman, respectively. Mildew was not observed on older Norway maple trees. The mildew occurred mainly on the upper leaf surface as patches of dense, white mycelium with scattered or gregarious cleistothecia. Mean diameter of the cleistothecia was 146 (± 13.4) μm. Short stalked and subsessile asci averaged 69 (± 4.1) μm × 48 (± 5.4) μm. Ascospores averaged 27 (± 3.2) μm × 12 (±0.9) μm. Appendages were deeply cleft, simple, or one to three times dichotomously branched. This mildew fits the description of the European species Sawadaea bicornis (Wallr:Fr.) Homma (1). Also, conforming to S. bicornis were chains of macroconidia (21 (± 2.7) × 14 (± 1.5) μm) and microconida. Fibrosin bodies were seen in both. Infection of only some young trees and its absence in previous years lead us to believe that the introduction is recent in the Pacific Northwest. The susceptibility of native maples to the Norway maple mildew remains to be determined. Specimens have been deposited in the U.S. National Fungus Collections (BPI 842088). References: (1) U. Braun. A monograph of the Erysiphales (powdery mildews) J. Cramer, Berlin-Stuttgart, 1987. (2) D. J. Nowak and R. A. Rowntree. J. Arboric. 16:291, 1990.
First Report of Burkholderia cepacia as a Pathogen of Banana Finger-Tip Rot in Taiwan
Authors: Lee Y.-A. , Shiao Y.-Y. , Chao C.-P. 
Published: May 2007

Banana finger-tip rot is an endemic minor disease in Taiwan. Diseased fingers are recognized externally by their distorted shape, often being narrow at the tip, smaller, and curved out of line with the other fingers. Parts of the pulp within the finger appear slightly gelatinous and yellow. Frequently, a brown discoloration is evident at the tip of the flower end. Although Pseudomonas sp. was reported to be a causal pathogen, the identity of the species was not determined (1). Isolations from diseased fingers consistently yielded bacterial colonies that were whitish-yellow on Luria-Bertani agar and did not produce fluorescent pigment on King's medium B. Three isolates were selected for further characterization. All isolates were gram negative, aerobic, and grew at 42°C, positive for oxidase, lysine decarboxylase, and ornithine decarboxylase, but negative for arginine dihydrolase and tryptophanase (indole production). The isolates hydrolyzed gelatin and esculin, produced acids by utilizing d (+)-glucose, mannose, sucrose, maltose, d-mannitol, d-sorbitol, and dulcitol, but not melibiose, or rhamnose. The isolates caused rotting symptom on onion that was more severe than on potato and carrot slices. The bacterium was identified as Burkholderia cepacia. Almost complete 16S rDNA sequence (1,489 bp; GenBank Accession No. AY207313) of one isolate (strain B9) was determined and compared with available 16S rDNA sequences of members of B. cepacia complex. The sequence was similar (99.87%) to that of B. cepacia genomovar III LMG 12614 (GenBank Accession No. AF097532). Bacterial suspensions (108 CFU/ml) were injected through the center of the stigma, and the fingers were enclosed in a plastic bag to maintain high humidity. Twenty fingers (three to four fingers in each hand) were inoculated totally. A majority (80%) of the wound inoculations were successful, and typical symptoms appeared in 10 to 14 days. Control plants were inoculated with sterile distilled water. A small amount (2 to 5%) of control plants also showed symptoms. This may result from finger infestation with epiphytic or endophytic B. cepacia. Young fruits were more susceptible than older fruits. The bacterium was readily reisolated from diseased fingers and confirmed as B. cepacia. To our knowledge, this is the first report of B. cepacia as a causal pathogen of banana finger-tip rot. Reference: (1) I. W. Buddenhagen. Plant Prot. Bull. 16:17, 1968.
First Report of Sclerotinia sclerotiorum on Niger (Guizotia abyssinica)
Authors: Bradley C. A. , Río L. E. del , Johnson B. L. 
Published: May 2007

Niger is a new crop being grown in North Dakota and Minnesota for the commercial birdseed market. In 2002, approximately 60 and 150 ha of niger were grown in North Dakota and Minnesota, respectively. In September 2002, niger plants in a field located near Prosper, ND showed the following symptoms and signs: bleached, shredded, and broken stems at the basal area, and presence of white mycelium and black sclerotia (2.2 ± 0.8 mm diameter) inside the pith cavity. Approximately 40% of plants in that field showed signs or symptoms of infection. Sclerotia were collected from the pith cavity, soaked in a 0.53% NaOCL solution for 30 s, air dried, and placed in petri dishes containing potato dextrose agar (PDA). A fungal colony grew out from the plated sclerotia that subsequently produced aerial white mycelium and black sclerotia characteristic of Sclerotinia sclerotiorum (Lib.) de Bary. To confirm pathogenicity, 2 groups of 10 30-day-old niger seedlings each were inoculated using the straw test method (2) or petiole inoculation test method (1) with mycelium from a S. sclerotiorum isolate obtained from an infected niger plant; 20 seedlings served as a noninoculated control. At the time of inoculation, seedlings were healthy and approximately 14 cm high. Three days after inoculation using either method, tissue at the inoculated area turned gray. The gray lesions progressed across the majority of the seedling tissue and 1 week after inoculation, all inoculated plants were wilted and dead. S. sclerotiorum was reisolated from infected tissue that was placed on PDA. To our knowledge, this is the first report of S. sclerotiorum causing a stem rot disease of niger or any species in the Guizotia genus. Several of the major crops grown in North Dakota and Minnesota, such as canola, dry edible bean, soybean, and sunflower are susceptible to S. sclerotiorum. Growing niger in rotation with these or other susceptible crops could increase S. sclerotiorum inoculum levels and lead to severe disease outbreaks if conditions are favorable. References: (1) L. E. del Río et al. (Abstr.) Phytopathology 90(Suppl.):S176, 2000. (2) R. Petzoldt and M. H. Dickson, Annu. Rep. Bean Improv. Coop. 39:142, 1996.
First Report of Ascochyta Blight of Chickpea Caused by Ascochyta rabiei in Chile
Authors: Galdames R. , Mera M. 
Published: May 2007

Chickpea (Cicer arietinum L.) plants with foliar and stem lesions fitting the description of Ascochyta blight were observed in October 2002 in four chickpea crops located in the La Araucania Region (38°S, 72°24′W) in southern Chile. Large, circular foliar and stem lesions containing pycnidia arranged in concentric circles were observed (1). Stem breakage also was observed. Isolates were obtained from mature pycnidia developed on stems by culturing a spore suspension on potato dextrose agar (PDA) and chickpea seed meal agar. A pathogenicity test was performed by inoculating 25 plants with a suspension of 1.2 × 105 conidia ml-1 and incubating at 22°C and 75% relative humidity. Foliar and stem lesions were observed 5 and 7 days after inoculation, respectively. Four check plants sprayed with sterile distilled water showed no symptoms. Fungal colonies obtained from inoculated plants showed the same cultural characteristics as the original isolates. Cultural morphology was consistent with the description of Ascochyta rabiei (Pass.) Labrousse (teleomorph Didymella rabiei (Kovacheski) v. Arx (= Mycosphaerella rabiei Kovacheski)) (3). Conidia produced on PDA were predominantly aseptate, 3.90 to 5.85 μm wide, and 9.75 to 11.7 μm long. Affected plants (cv. Kaniva) originated from seed introduced at commercial volumes (69 ton) from Victoria, Australia in August 2002. A. Rabiei can be disseminated via infected seed (1). Ascochyta blight symptoms also have been observed in small patches in several crops near Temuco, the capital of the La Araucania Region. Chickpea production is currently, relatively small in southern Chile, however, plans to promote its cultivation may be hindered by this outbreak. Previously, the only other country to report Ascochyta blight of chickpea in South America was Bolivia (2). References: (1) W. J. Kaiser. Epidemiology of Ascochyta rabiei. Pages 117–134 in: Disease-resistance Breeding in Chickpea. K. B. Singh and M. C. Saxena, eds. ICARDA, Aleppo, Syria, 1992. (2) W. J. Kaiser et al. Plant Dis. 84:102, 2000. (3) E. Punithalingam and P. Holliday. No. 337 in: CMI Descriptions of Pathogenic Fungi and Bacteria. CMI, Kew, Surrey, UK, 1972.
First Report of Plectosporium Blight on Pumpkin Caused by Plectosporium tabacinum in Alabama
Authors: Mullen J. M. , Sikora E. J. 
Published: May 2007

In October of 2001, Plectosporium tabacinum (van Beyma) M.E. Palm, W. Gams, & H.I. Nirenberg (formerly known as Microdochium tabacinum (von Arx, 1984) and Fusarium tabacinum (Gams & Gerlagh, 1968)) was observed in field plantings of pumpkin (Cucurbita pepo L.) in Cullman and Jackson counties in north Alabama. Symptoms were white or tan, spindle-shaped lesions on the stems and leaf petioles and slightly raised, corky, white or light brown lesions on pumpkin fruit and fruit stems. Pumpkin symptoms were identical to a previous description of P. tabacinum (published as M. tabacinum) on pumpkin, zucchini, and yellow summer squash (1). Disease severity ranged from less than 10% stem tissue damage on pumpkins in Cullman County to 40 to 45% stem tissue damage on pumpkins in Jackson County. A field section of pumpkins in Jackson County sprayed with azoxystrobin (Quadris 2.08F, 0.20 kg a.i./ha) alternated weekly with chlorothalonil (Bravo Ultrex, 2.44 kg a.i./ha) beginning at vine-run had stem damage of approximately 5% compared to approximately 45% stem damage on pumpkins in an unsprayed field section. A 50% reduction in marketable fruit due to P. tabacinum was observed in the unsprayed field section compared to the section sprayed weekly with fungicides. When thin slices of lesions were taken from stem and fruit surfaces using a scalpel and examined microscopically, one- or two-celled, hyaline, bilaterally symmetric spores, 7.0 to 8.5 × 2.8 to 3.0 μm were observed. The ends of the spores were slightly narrowed and rounded. Spore characteristics were identical to previous descriptions of P. tabacinum produced in culture and on diseased pumpkins and squash (2,3). Surface-sterilized tissue from fruit lesion margins was plated on potato dextrose agar and incubated under light (Sylvania Gro-Lux, 40w) with a light/dark cycle of 12 h at 23°C. After 10 days, spores were observed that were similar to those from fruit except they were multiguttulate and had a phialide arrangement. The fungal mycelium was pale pink to pale orange and closely appressed to the agar. Fungal characteristics in culture agree with a previous description of P. tabacinum in culture (2). To our knowledge, this is the first report of P. tabacinum in Alabama. References: (1) S. C. Bost and C. A. Mullins. Plant Dis. 76:861, 1992. (2) M. E. Palm et al. Mycologia 87(3):397, 1995; (3) T. A. Zitter. Microdochium blight. Page 28 in: Compendium of Cucurbit Diseases. T. A. Zitter, D. L. Hopkins, and C. E. Thomas, eds. The American Phytopathological Society, St. Paul, MN, 1996.
First Report of Resistance to Metalaxyl in Downy Mildew of Sunflower Caused by Plasmopara halstedii in Spain
Authors: Molinero-Ruiz M. L. , Melero-Vara J. M. , Gulya T. J. , Dominguez J. 
Published: May 2007

Fifty-two isolates of Plasmopara halstedii Farl. Berl. & de Toni (causal agent of sunflower downy mildew) collected from sunflower (Helianthus annuus L.) in Spain from 1994 to 2000 were evaluated for metalaxyl resistance. The pathogen was identified on the basis of the morphology of the sporangiophores and zoosporangia recovered on the underside of the leaves (2). Metalaxyl (Apron 20% LS) at 2.0 g a.i./kg of seed (labeled European rate) was applied as seed dressing to the susceptible sunflower ‘Peredovik’. There were two replications of 40 plants, and the test was repeated three times. Inoculum (sporangia bearing zoospores) was produced on artificially inoculated plants. Seed were germinated in a humidity chamber at 28°C for 24 to 48 h. When the radicle was 0.5 to 1.0 cm long, untreated and treated seedlings were inoculated by dipping the entire plant in an aqueous suspension of 6.0 × 104 sporangia per ml for 4 h, planted in a sand/perlite mixture (2:3 vol/vol), and grown at 16 to 21°C with a 12-h photoperiod. Plants were incubated for 24 to 48 h at 100% relative humidity and 15°C in the dark to enhance sporulation. After 12 days, disease incidence (DI) of inoculated plants was determined as a percentage of plants displaying sporulation of the fungus on the cotyledons and/or true leaves (3). DI was 95 to 100% for the untreated seedlings, but mildew did not develop on seedlings treated with metalaxyl for 51 of the isolates. The remaining isolate caused symptoms on 67% of the treated plants. This isolate was tested in another experiment in which ‘Peredovik’ seed was treated with metalaxyl at 0, 0.5, 2.0, 3.5, and 5 g a.i./kg of seed. There were four replications of 12 seedlings per treatment, and seedlings were inoculated as described previously. DI in the untreated control was 77%, which was not significantly different from the DI for seed treated with metalaxyl at 0.5, 2.0, and 3.5 g a.i./kg of seed (97, 73, and 96%, respectively). DI for seed treated with metalaxyl at 5.0 g a.i./kg of seed was 37%, which was significantly lower than the other treatments. Although resistance of P. halstedii to metalaxyl has been reported in France (1), to our knowledge, this is the first report of resistance of sunflower downy mildew to metalaxyl in Spain. References: (1) J. M. Albourie et al. Eur. J. Plant Pathol. 104:235, 1998. (2) G. Hall, Mycopathologia 106:205, 1989. (3) M.L. Molinero-Ruiz et al. Plant Disease 86:736, 2002.
First Report of Phaeomoniella chlamydospora on Vitis vinifera, Vitis labrusca, and French American Hybrids in Pennsylvania and New York
Authors: Stewart E. L. , Wenner N. G. , Hed B. E. 
Published: May 2007

Phaeomoniella chlamydospora (W. Gams, Crous, M.J. Wingfield. & L. Mugnai) Crous & Gams (= Phaeoacremonium chlamydosporum) was isolated during the growing seasons of 2001 and 2002 from roots, trunks, and cordons of grapevines including cultivars Concord, Niagara, Steuben, Catawba, Dutchess, DeChaunac, Vidal, Seyval, Chambourcin, Chardonnay, Riesling, Sangiovese, Dolcetto, Baco Noir, Merlot, Villard, Pinot Gris, GR7, and 3309C root stock representing 18 locations in Eastern, Central, and Lake Erie regions of Pennsylvania as well as the Lake Erie and Finger Lakes regions of New York. P. chlamydospora was isolated from 89% of samples from vines 3 to 45 years old showing decline symptoms in the field. Isolates were identified based on a previous description (1) and by internal transcribed spacer (ITS1-5.8S-ITS2) rDNA sequences identical to those of P. chlamydospora isolated from Vitis vinifera from Italy (ex-type culture CBS229.95, GenBank Accession No. AF197973). P. chlamydospora is firmly established as a member of the petri and esca disease complex and as a pathogen of grapevines (2,3). To test pathogenicity of our isolates, approximately 30 μl of a 106 conidia/ml suspension, obtained from six isolates, was injected into the pith of 60 single-node, dormant, unrooted cuttings of ‘3309C’ and ‘Concord’. Ten control cuttings of ‘Concord’ and ‘3309C’ were injected with an equal volume of sterile distilled water. From 24 to 32 weeks after inoculations, all P. chlamydospora-inoculated cuttings exhibited dark streaking of the vascular tissue extending 45 to 50 mm from the point of inoculation. The vascular streaking observed in inoculated plants was identical to symptoms observed in declining vines in the vineyard. Vascular streaking was absent in the controls. P. chlamydospora was isolated as a monoculture from regions of vascular streaking in 89% of inoculated cuttings. P. chlamydospora was not isolated from the water-treated controls. P. chlamydospora is widespread and readily isolated from declining grapevines in Pennsylvania, New York, and other national and international grape growing regions. To our knowledge, this is the first report of P. chlamydospora from the cultivars cited above in Pennsylvania and New York. References: (1) M. Groenewald et al. Mycol. Res. 105:651, 2001. (2) Phytopathol. Mediterr. 39(1), 2000. (3) Phytopathol. Mediterr. 40, Supplement 2001.
First Report of the Rust Miyagia pseudosphaeria on Sonchus oleraceus in the Americas
Authors: Hernández J. R. , Koike S. T. , Scheck H. J. , Hernández M. E. Palm 
Published: May 2007

In January 2002, a rust was observed on leaves and stems of the weed Sonchus oleraceus L. (annual sowthistle) in Santa Barbara, CA. Infected plants were collected in Santa Barbara and Monterey counties, CA. Specimens were examined microscopically and compared with a published description (1) and herbarium specimens at the USDA National Fungus Collection, Beltsville, Maryland. The fungus was identified as Miyagia pseudosphaeria (Mont.) Jorst. based on characteristics of the uredinia and urediniospores. The uredinial sori were subepidermal, erumpent, and single or in groups. Sori were surrounded by peripheral, laterally connected, chestnut brown paraphyses that initially enclosed the developing urediniospores and eventually opened partially at the apex, breaking the host epidermis and remaining as a wall surrounding the spores. The urediniospores were ellipsoid, ovoid, or pyriform with yellowish, often granular, contents and measured 21.5 to 43 × 17 to 26.5 μm. The urediniospore walls were hyaline and finely echinulate and 2.5 to 3.5 μm thick with germ pores sometimes evident in median view. The paraphyses were 70 to 140 × 6 to 8 μm, thick-walled, hyaline below, chestnut brown above, and often somewhat wider or dichotomously branched at the apex. To test pathogenicity, a spore suspension (4.7 × 104 spores/ml) was sprayed onto 7-week-old annual sowthistle plants. Plants were incubated in a dew chamber for 48 h and maintained in a greenhouse at 22 to 24°C. Signs of rust were observed after 2 weeks, and microscopic examination confirmed that the same fungus was present. Uninoculated control plants did not develop rust. Using the same method, plants of prickly sowthistle (S. asper (L.) Hill) were inoculated and also developed the disease. All inoculation experiments were conducted two times and the results were the same. The rust was found on almost all annual sowthistle plants examined in Santa Barbara County, especially well-nourished specimens growing as weeds in irrigated landscapes, vegetable fields, or in container nurseries. Diseased plants were found in and around vegetable fields in Monterey County. M. pseudosphaeria is macrocyclic, autoecious, and known only on Sonchus spp. It has been reported from northern Africa, China, Europe, Japan, New Zealand, and the former Soviet Union. To our knowledge, this is the first report of M. pseudosphaeria in the Americas. Voucher specimens have been deposited in the U.S. National Fungus Collection (BPI 842025, 842055 to 842060, and 842230). Images can be viewed at nt.ars-grin.gov . References: (1) M. Wilson and D. M. Henderson. British Rust Fungi. Cambridge University Press, Cambridge, 1966.
Buckeye Rot of Tomato Caused by Phytophthora capsici in Michoacan, Mexico
Authors: Fernández-Pavía S. P. , Rodríguez-Alvarado G. , Sánchez-Yañez J. M. 
Published: May 2007

The state of Michoacan is one of the main fresh pepper (Capsicum annuum L.) and tomato (Lycopersicon esculentum Mill.) producers in Mexico. During the last 5 years, pepper-producing areas in the state have become unproductive due to root-rotting pathogens, mainly Phytophthora capsici Leonian. Growers trying to overcome losses have increased tomato production in areas previously used for pepper production. Field-grown tomato plants with diseased green tomato fruits were observed in Tacambaro, Michoacan, during August 2002. Initially, brown-to-black lesions developed on fruits in contact with soil, followed by infection of the upper fruits in the raceme. Lesions enlarged and dark zonate “buckeye” bands were formed in the affected area. Diseased fruit turned mushy. Symptoms observed were similar to those described for buckeye rot of tomato (1). Diseased fruit were surface disinfested with 70% ethanol, cut into 0.5-cm slices, and incubated in a moist chamber to induce mycelial colonization. Isolation from mycelial tufts growing through the tomato slice was performed 3 days later, and mycelia was transferred to PARP selective medium (corn meal agar (CMA) plus ampicillin, pimaricin, rifampicin, and pentachloronitrobenzene). P. capsici was consistently isolated from diseased tomato fruits. Oomycete identification was based on sporangial and gametangial characteristics of cultures grown on CMA (1). Sporangia microscopically observed were spherical, broadly ellipsoid or obovoid with one papilla (occasionally two papillae), and deciduous with a long pedicel. Chlamydospores were not present (2). The isolates were heterothallic, and oogonia with amphigynous antheridia were observed in pairings with A1 and A2 isolates of P. capsici. Three isolates were A1 and two isolates were A2. To confirm pathogenicity, two experiments were performed using 20 healthy unwounded green tomatoes. One isolate of each mating type was tested. Isolates were grown for 5 days on CMA, and fruits were inoculated by placing P. capsici in contact with the fruit. Inoculated fruits were kept in a moist chamber at room temperature (17 to 20°C). Initial symptoms in the form of brown-to-black lesions appeared 24 h after inoculation. One week after inoculation, symptoms were similar to those observed in field-grown plants, and P. capsici was recovered from the margins of the diseased tissue. All inoculated fruits rotted. To our knowledge, this is the first report of P. capsici causing buckeye rot on tomato in Michoacan and of the presence of both mating types in the area. Reference: (1) D. C. Erwin and O. K. Ribeiro. Phytophthora Diseases Worldwide. The American Phytopathological Society. St. Paul MN, 1996. (2) M. Aragaki and J. Y. Uchida. Mycologia 93:137, 2001.