bluuebunny/crossref_metadata_2025_split huggingface dataset:
First Report of White Rust Caused by Albugo bliti on Seabeach Amaranth in the United States
Authors: Keinath A. P. , Strand A. E. , Hamilton R. D. 
Published: May 2007

Seabeach amaranth (Amaranthus pumilus Raf.), a threatened annual marine plant, is a primary colonizer of the windward side of Atlantic coastal dunes. It serves an important ecological role in dune accumulation and stabilization. Because Hurricane Floyd eliminated all native seabeach amaranth in South Carolina in 1999, experimental reestablishment plantings have been attempted. In August 2000, seabeach amaranth on Dewees and Cape Island in Charleston County, Huntington Beach in Georgetown County, and Otter Island in Colleton County, South Carolina were stunted and senesced prematurely. Leaves on affected plants were only one-half of the normal size and internodes were shortened. Most plants (>90%) at each location were affected. Diseased leaves had small, pale green-to-tan spots above hypophyllous pustules that contained numerous, dry, hyaline, subglobose conidia. Conidia measured 13.5 (10 to 17) × 15.0 (11 to 18) μm. Based on morphological characters and the host, the pathogen was identified as Albugo bliti (Biv.-Bern.) Kuntze (1,2). No oospores were observed. Diseased plants were collected from Dewees and Otter Islands and kept frozen for use as a source of inoculum. Six A. pumilus plants each of six Plant Introductions (PI), 553080 through 553085, that had been grown from seed were sprayed with a suspension of 4.7 × 105 conidia per ml. One plant of each PI was sprayed with sterile distilled water as a noninoculated control. All plants were placed in a humidity chamber for 48 h and then moved to a greenhouse bench. Thirteen days after inoculation, all inoculated plants had pustules of white rust. Diseased plants had a mean of 42 pustules per plant and PI's did not differ in susceptibility. Five of six noninoculated plants also had white rust pustules, but only a mean of 2.3 (range 1 to 5) pustules each. White rust likely appeared on noninoculated plants because plants were spaced closely together in the chamber. Pustules and conidia on inoculated plants were identical to those on plants collected originally. Albugo bliti has been reported on 19 other Amaranthus species (1), but to our knowledge, this is the first report of white rust on seabeach amaranth in the United States. White rust reduced the biomass of infected plants and, hence, their ability to trap sand. White rust was not observed on subsequent plantings in 2001 and 2002 at any location. References: (1) D. F. Farr et al. Fungal Databases. Systematic Botany and Mycology Laboratory, On-line publication. ARS USDA, 2002. (2) G. W. Wilson. Bull. Torrey Bot. Club 34:61, 1907.
First Report of Phytophthora cactorum on American Ginseng (Panax quinquefolius) in Bulgaria
Authors: Bobev S. G. , Baeyen S. , Crepel C. , Maes M. 
Published: May 2007

American ginseng (Panax quinquefolius) is a recently introduced crop in Bulgaria. In autumn 2001, several 2-year-old plants from Stara Zagora County exhibited symptoms of wilting and dying. Laboratory analysis also revealed some browning of the ginseng root surface and discoloration of the vascular tissues. During later stages of the disease, roots became soft, rubbery, and disintegrated. After storage in a humid chamber for 3 to 5 days, roots were covered with a white, cottony mycelium. Following the transfer onto potato dextrose agar, this fungus formed rounded colonies of white, aerial mycelium. Pathogenicity of the isolate was demonstrated by inoculation of roots that were surface-disinfected with alcohol (70%) for 30 s and rinsed with sterile water. Roots were wounded with a scalpel, and agar pieces from a 1-week-old culture were placed under the cortical tissue. Five inoculated root pieces were kept in a humid chamber at 24 to 25°C, and the pathogen was reisolated subsequently from necrotic lesions that developed from wounds. No symptoms were found in the five wounded but noninoculated control roots. The pathogen was reisolated from the diseased tissue to fulfill Koch's postulates. Microscopic examination showed that the pathogen had an aseptate mycelium (mean diameter of 5.3 μm), did not form hyphal swellings or chlamydospores, and had simple sympodial branching of the sporangiophores. Sporangia had a caducous nature with a pedicel length of 4.7 μm (1.7 to 6.7 μm). Sporangia were ovoid to obpyriform in shape, papillate, and nonproliferating measuring 30.6 (26.6 to 40.0) μm × 24.3 (23.3 to 30.0) μm. The length/width ratio varied between 1.25 and 1.3. The fungus was homothallic and produced paragynous antheridia and spherical oogonia with a diameter of 30.6 μm (26.6 to 33.3 μm) on V8 agar and in petri solution. Oospores were aplerotic and spherical (25 to 30 μm in diameter). Based on symptoms and pathogen characteristics (2), the disease was identified as Phytophthora root rot caused by Phytophthora cactorum. Additionally, the identity of the isolate was verified by sequence determination of the ribosomal internal transcribed spacer I region and alignment to the GenBank-EMBL DNA database (1), which revealed 100% sequence similarity with P. cactorum. To our knowledge, this is the first report of P. cactorum on American ginseng in Bulgaria. References: (1) S. F. Altschul et al. Nucleic Acids Res. 25:3389,1997. (2) D. C. Erwin and O. K. Ribeiro. Morphology and identification of Phytophthora species. Pages 96–125 in: Phytophthora Diseases Worldwide. The American Phytopathological Society, St. Paul, MN, 1996.
First Report of Potato mop-top virus on Potato from the United States
Authors: Lambert D. H. , Levy L. , Mavrodieva V. A. , Johnson S. B. , Babcock M. J. , Vayda M. E. 
Published: May 2007

Potato mop-top virus (PMTV) is a tripartite pomovirus vectored by the powdery scab plasmodiophoromycete Spongospora subterranea pv. subterranea (1). PMTV occurs on potato (Solanum tuberosum) in Europe, the Andes, Asia, and Canada. Internal necrotic arc and fleck tuber symptoms (“spraing”) may reduce commercial acceptance of some cultivars (3). PMTV symptoms were discovered in ‘Shepody’ tubers at the Aroostook Research Farm, Presque Isle, ME in May 2002 and subsequently in ‘Russet Burbank’ tubers in commercial storage from the 2001 Maine crop. Symptomatic tubers exhibited single or multiple concentric necrotic arcs that were partial or complete, but exhibited no distinct external symptoms. The presence of PMTV in eight ‘Shepody’ tubers was indicated by positive enzyme-linked immunosorbent assay (ELISA; Adgen, Ltd., Auchincruive, Ayr, Scotland) and confirmed by reverse transcription polymerase chain reaction (RT-PCR). ‘Russet Burbank’ potatoes were visually diagnosed, and the corresponding halves of 128 symptomatic tubers were forwarded to the University of Maine and APHIS (Beltsville, MD). Of these, ELISA readings in Maine were strongly positive (>3 × background) for 88, ambiguous (1.5-3 × background) for 13, and negative for 27. Subsamples from these three categories were positive by PCR in 17 of 17, 9 of 9, and 12 of 14 cases, respectively. A similar rating, positive or ambiguous, in ELISA testing was identical for all but one case at Beltsville. Confirmation of PMTV required PCR testing, resulting in a characteristic PCR product of 401 bp that was generated from the coat protein coding region on RNA 2 (2) using the primer pair PMTV 1 5′-GCAGCCGTCGAGAATAGATA-3′ (RNA nucleotides 316–335) and PMTV 4 5′-GCGAGTTGATGTGCC ACATT-3′ (complementary to RNA 2 nucleotides 716–697). An immunocapture RT-PCR using this primer set and the coating antibody from the Adgen ELISA kit was also successful in detecting PMTV. In separate reactions, a second product of 646 bp was generated from the triple gene block on RNA 3 (4) using the primer pair PMTV 5 5′-GGTGAACACGAGGACAAGGT-3′ (RNA 3 nucleotides 1417–1436) and PMTV 7 5′-AACAGTCCGGTCTTGTGAAC-3′ (complementary to RNA 3 nucleotides 2063–2044). The sequence of these products was 98 to 100% identical to PMTV published sequences. The discovery of this virus will result in adjustments to U.S. and Canadian seed potato certification standards and symptom characterization for common North American cultivars. References: (1) R. A. C. Jones and B. D. Harrison. Ann. Appl. Biol 63:1, 1969. (2) S. Kashiwazak et al. Virology 206:701, 1995. (3) M. Sandgren et al. Am. J. Potato Res. 79:205, 2002. (4) K. P. Scott et al. J. Gen. Virol.75:3561, 1994.
First Report of Anthracnose Caused by Colletotrichum gloeosporioides on Taxus mairei in Taiwan
Authors: Fu C. H. , Hsiao W. W. , Yao J. C. 
Published: May 2007

Taxus mairei (Lemee & Levl.) S.Y. Hu ex Liu is a giant evergreen tree native to Taiwan. T. mairei and the Pacific yew, T. brevifolia, produce taxol, a highly effective antitumor drug. Anthracnose was observed on cuttings and seedlings of T. mairei in nurseries and on larger plants grown in plantations in Taiwan. Circular or irregular, brown leaf spots were associated with defoliation. Stems lesions and tip dieback were also observed. Colletotrichum gloeosporioides (Penz.) Sacc. was isolated from diseased tissues, and this fungus grew well on potato dextrose agar and malt extract agar (MEA), with a growth rate of 6.3 mm per day on MEA at 32°C in the dark. Colonies were white to grayish white and became dark gray with age. Acervuli produced on leaves were 115 to 155 μm in diameter, with one or several brown-to-black setae and pale salmon conidial masses. Conidia were guttulate, straight, cylindrical, obtuse at the apex and truncate at the base, and approximately 12 to 17 × 3.5 to 6.0 μm. The disease was reproduced by spraying T. mairei seedlings with a suspension of 104 to 105 conidia per ml, and the control plants were inoculated with distilled water. Inoculated plants were kept in a transparent moist chamber with a constant humidity near 100% (1). Symptoms appeared within 7 days when the temperature was over 32°C. When the temperature was below 24°C, symptoms were delayed. The fungus was reisolated from the inoculated plants, fulfilling Koch's postulates. To our knowledge, this is the first record of anthracnose on Taxus mairei (2), and anthracnose appears to be the most important disease on this plant in Taiwan. Voucher specimens have been deposited at the Division of Forest Protection, Taiwan Forest Research Institute as TFRIFCH Herbarium specimen 137. References: (1) W. W. Hsiao et al. Taiwan J. For. Sci.17:119, 2002. (2) Y. P. Tsai, ed. List of plant diseases in Taiwan. The Plant Protection Society of the Republic of China and The Phytopathological Society of the Republic of China, 1991.
An Outbreak of a Leaf Spot Disease of Cabbage in Southern Florida Caused by Xanthomonas campestris pv. armoraciae
Authors: Pernezny K. , Jones J. B. , Roberts P. D. , Dickstein E. 
Published: May 2007

From October to December 2001, a leaf spot disease was observed in numerous commercial fields of red and green cabbage (Brassica oleracea var. capitata L.) in the Everglades Agricultural Area, south and east of Lake Okeechobee and in the environs of Immokalee in southwestern Florida. Discrete water-soaked to greasy appearing spots were observed in the leaf blades with no evidence of marginal V-shaped lesions characteristic of black rot caused by Xanthomonas campestris pv. campestris. Profuse bacterial streaming was observed when cut leaf sections were examined microscopically. A bacterium that formed yellow colonies on nutrient agar was consistently isolated from these lesions. Ten bacteria were isolated, purified, and characterized. All strains were aerobic, gram-negative rods. Strains were positive for esculin hydrolysis, proteolysis in litmus milk, and gelatin liquefaction. Strains were negative for urease production, nitrate reduction, oxidase, and utilization of asparagine as a sole source of carbon and nitrogen. Fatty acid methyl ester analysis indicated a match with Florida library strains of X. campestris pv. raphani (similarity indices 0.605–0.738). Suspensions (2 × 107 CFU/ml in phosphate-buffered saline) of two Oklahoma strains identified as X. campestris pv. armoraciae provided by J. P. Damicone (3) and four representative Florida strains were applied to plants using a hand-held sprayer. Pathogenicity of the strains was tested on three replicate greenhouse-grown plants of the following: green cabbage cv. Market Early; red cabbage cv. Salad Delight; radish cv. Red Silk; tomato cv. Sunny; sweet bell pepper cv. Jupiter; and fresh horseradish roots purchased from a retail grocery chain. A strain of X. campestris pv. campestris originally isolated from Homestead, FL was also included in pathogenicity tests. All Florida and Oklahoma strains produced leaf spots, but no V-shaped lesions, on leaves of green cabbage, red cabbage, radish, tomato, and horseradish. Typical black rot symptoms were observed only in radish and green and red cabbage inoculated with the X. campestris pv. campestris strain. On the basis of these results, we identify the Florida strains as X. campestris pv. armoraciae (1,2,3), recognizing the precedent of X. campestris pv. armoraciae over X. campestris pv. raphani based on extensive genetic and serological data (1). Our strains appear to be more similar to those causing outbreaks on crucifers in Oklahoma (3) than those in Ohio (2), because Florida strains were pathogenic on tomato. References: (1) A. M. Alvarez et al. Phytopathology 84:1449, 1994. (2) F. Sahin and S. A. Miller. Plant Dis. 81:1334, 1997. (3) Y. Zhao et al. Plant Dis. 84:1008, 2000.
First Report of Sclerotium rolfsii on Kenaf in South Africa
Authors: Swart W. J. , Tesfaendrias M. T. , Terblanche J. 
Published: May 2007

Kenaf, Hibiscus cannabinus L. (Malvaceae), is being planted commercially in South Africa for the high quality cellulose fibers that it produces. In a January 2001 survey of 3-month-old kenaf plants grown from seed in experimental plots near Rustenburg, Northwest Province, 30% of plants were observed with severe wilting. Stems at ground level of all infected plants had sunken tan lesions, white mycelial strands, and small, dark brown, 1 to 2 mm diameter sclerotia. Isolations from diseased stem tissue on malt extract agar (MEA) consistently yielded a fungus conforming to the description of Sclerotium rolfsii Sacc. (teleomorph Athelia rolfsii (Curzi) Tu & Kimbrough). Pathogenicity tests were conducted by applying toothpick tips (5 mm) colonized by S. rolfsii on MEA to the stems of 120-day-old potted plants of 10 kenaf cultivars in the greenhouse. Five plants of each cultivar were wounded once using a sharp dissecting needle, and a colonized toothpick tip was placed on top of each wound. Control treatments consisted of five plants per cultivar each wounded and inoculated with sterile toothpick tips. All inoculation points were wrapped using Parafilm, and the experiment was conducted twice. Lesions were measured after 10 days. Mean lesion lengths for the 10 cultivars were as follows: Dowling (34.9 mm), Cuba 108 (38.6 mm), Gregg (41.1 mm), Everglades 41 (44.2 mm), SF459 (44.9 mm), Tainung 2 (45.8 mm), El Salvador (45.9 mm), Whitton (46.1 mm), Everglades 71 (46.4 mm), and Endora (54.0 mm). The Newman-Keuls multiple comparison test revealed that cvs. Dowling and Endora were significantly more resistant and more susceptible (P < 0.05), respectively, than the other cultivars. Lesions did not develop on control plants. The fungus was reisolated on MEA from all artificially inoculated plants. The pathogen is reported to cause serious losses in yield and fiber quality of kenaf (1). To our knowledge, this is the first report of S. rolfsii on kenaf in South Africa. Commercial plantings of kenaf in South Africa are expected to exceed 500 ha during the next 2 years, so its potential impact on kenaf production in this country will be significant if efficient disease control measures are not practiced. References: (1) J. M. Dempsey. Kenaf. Pages 203–304 in: Fiber Crops. The University Press of Florida, Gainesville, 1975.
A New Tomato yellow leaf curl virus Strain in Southern Spain
Authors: Morilla G. , Antúnez C. , Bejarano E. R. , Janssen D. , Cuadrado I. M. 
Published: May 2007

Tomato yellow leaf curl disease (TYLCD) has affected tomato crops annually in southern Spain since 1992 when Tomato yellow leaf curl Sardinia virus (TYLCSV-ES) was first described. In 1997, the presence of a different begomovirus species (TYLCV-[ES7297]) was reported in common bean (Phaseolus vulgaris). In 1999, TYLCV-[ES7297] was found in pepper (Capsicum annuum) (2). In September 2002, we observed tomato plants of TYLCD tolerant tomato cultivars (Kampala and Tiway) showing strong TYLCD symptoms (shortened internodes, curling of leaflet margins, and leaf blade reduction). Samples from 90 of these plants were collected from greenhouses located in the Province of Murcia and analyzed by Southern blot using the intergenic region of TYLCSV-ES[2] and TYLCV-[ES7297] as specific probes. Positive signals were obtained for TYLCV-[ES7297] and TYLCSV-ES[2] in 88 and 23 of the plants, respectively. Samples from eight TYLCV single-infected plants (four ‘Kampala’ and four ‘Tiway’) were analyzed by polymerase chain reaction using a pair of primers (OTYA7: GCTCCCTGAATGTTCGGATGGA and OTYA8: ATCATGGATTT ACGCACAGGGG) designed to amplify a 1.9-kb fragment of any isolate of TYLCV/TYLCSV. Subsequent restriction fragment length polymorphism analysis of the amplification products yielded a restriction pattern different from that obtained for TYLCV-[ES7297]. Fragments from the eight samples were sequenced and showed 97.9% identity to a TYLCV strain previously reported in Israel (X15656) (1) and only 92.7% identify with TYLCV-[ES7297]. To our knowledge, this is the first report that this strain of TYLCV has been detected in Spain. References: (1) N. Navot et al. Virology 185(1), 151, 1991. (2) J. Reina et al. Plant Dis. 83:1176, 1999.
First Report of Leaf Blotch Caused by Marssonina coronaria on Apple in Italy
Authors: Tamietti G. , Matta A. 
Published: May 2007

During the early summers of 2001 and 2002, in Forno Canavese in northwest Italy, a leaf disease was observed on the old apple cv. Furnas in a domestic orchard. Lesions on the upper side of the leaf were brownish, irregular in size and shape with somewhat dendritic margins, became black, and often coalesced with time. On the underside, lesions were smaller with more definite margins. Beginning in July, scattered acervuli (95 to 170 μm) were observed erupting through the epidermis on the upper side of leaves. Conidia were ampule shaped, 1-septate, constricted at the septum, hyaline, guttulate, and 6.1 to 8.4 × 14.6 to 22.0 μm. Severely diseased leaves abscised prematurely. The fungus was identified as Marssonina coronaria (Ellis & J.J. Davis) J.J. Davis, teleomorph Diplocarpon mali (1) although the conidia were slightly shorter than those originally described for this fungus. Monoconidial isolates were obtained by spreading mini-suspensions of conidia taken from acervuli on malt agar (MA) and transferring single-germinated conidia to MA, potato dextrose agar, V8 agar, or apple leaf agar (ALA). The fungus grew slowly, producing small colonies on V8 and ALA only. On ALA medium, after 3 months incubation at 20 to 22°C, the colonies were 5 to 7 mm in diameter with light brown, irregular margins and dark brown centers bearing acervuli. Conidia from pure cultures were collected, suspended in sterile, distilled water (250,000 ml-1), and sprayed on the leaves of three ‘Golden Delicious’ apple shoots maintained in a mist chamber at 20 to 25°C for 2 weeks. In two independent experiments, the fungus reproduced symptoms like those observed on ‘Furnas’ and was reisolated from acervuli. No symptoms were observed on water-treated controls. To our knowledge, apple leaf blotch has not previously been reported in Italy. Although now it is a minor disease, it could become more important in sustainable crops because of its relatively low sensitivity to copper fungicides (2), the only products that can be used under that program. References: (1) Y. Harada et al. Ann. Phytopathol. Soc. Jpn. 40:412, 1974. (2) J. Ruide et al. China Fruits 2:51, 1997.
Outbreak of Choanephora Blight Caused by Choanephora cucurbitarum on Green Bean and Pepper in Florida
Authors: Roberts P. D. , Urs R. R. , Kucharek T. A. , Semer C. R. , Benny G. L. , Pernezny K. 
Published: May 2007

Severe outbreaks of Choanephora blight on green bean (Phaseolus vulgaris cvs. Bronco, Shade, and Gold Mine) and bell pepper (Capsicum annuum cvs. Aristotle, Crusader, and Sentry) were widespread in southwestern (Hendry and Collier counties) and northern Florida (Alachua County) in October and November 2002. Disease incidence, estimated by inspecting 100 randomly selected bean plants in each of four fields, was 40 to 100% and infected fruit ranged from less than 10 to 100%. Incidence estimated similarly on pepper plants in three fields was 35 to 40% with substantial fruit infection observed predominantly around the calyx. Zucchini fruit and a pigweed plant (Amaranthus sp.) were observed with sporulating lesions of Choanephora, indicating that other hosts were affected during the outbreak. Symptoms were blighted leaves, dieback of shoot tips, blighted blossoms, and black, soft-rot lesions on fruit. Choanephora sp. was sporulating in abundance on diseased tissue. Isolates of Choanephora sp. grew readily as pure cultures on acidified potato dextrose agar and malt yeast extract (MYE) agar. C. cucurbitarum (Berk. & Rav.) Thaxter was identified on the basis of shape and ornamentation of the sporangiola (1). The sporangiola of C. cucurbitarum are ellipsoid to broadly ellipsoid, and the wall is usually longitudinally striate. Pathogencity tests consisted of spray inoculation (5,000 spores per ml) of five 6-week-old plants each with and without wounding made by lightly scratching the leaf surface with a needle. Plants were placed in the greenhouse with temperatures ranging from 21 to 26°C, and symptom development was observed as early as 3 days after inoculation. The percentage of infected plants after wounding was 40% for bell pepper (‘Enterprise’), 100% for green bean (‘Opus’), 0% for watermelon (Citrullus lanatus ‘Star Gazer’), 60% for cantaloupe (Cucumis melo ‘Vienna’), and 20% for cucumber (Cucumis sativus ‘Thunder CY’). Lesions on inoculated leaves were similar to those seen in the field on bean and pepper, and sporulation of C. cucurbitarum was present in the necrotic areas on all symptomatic plants. Pure cultures of C. cucurbitarum were reisolated. C. curcurbitarum was observed and isolated from a few noninoculated bean flowers and two noninoculated bean pods indicating spread to noninoculated plants; otherwise control plants were asymptomatic. Unwounded plants did not develop lesions, indicating that wounding was necessary for infection by this inoculation technique. The mating type was determined by juxtaposing several isolates on MYE agar, and zygospore formation was observed indicating both + and - strains occur in Florida. These outbreaks show that under the proper environmental conditions, such as long periods of high rainfall, high humidity, and high temperatures, crops like bean and pepper that are not usually affected by the disease may experience significant damage. Reference: (1) P. M. Kirk. Mycol. Pap. 152:1–61, 1984.