bluuebunny/crossref_metadata_2025_split huggingface dataset:
First Report of Southern blight Incited by Sclerotium rolfsii on Dichondra repens in Italy
Authors: Garibaldi A. , Minuto A. , Gullino M. L. 
Published: May 2007

Kidney weed (Dichondra repens) is increasingly used for low maintenance turf in Italy, particularly for gardens and parks in areas characterized by mild climate. During September 2003, on the D. repens turf of a private garden located near Imperia (northern Italy), yellow, circular areas as much as 60 cm in diameter appeared with the grass becoming chlorotic and thin. A ring of the patch at its periphery exhibited a reddish brown color and eventually died. An area of green grass remained in the center of the patch. Rings of dead grass enlarged rapidly during hot, humid weather. In the presence of abundant moisture, a white mycelium occurred on the dying grass at the periphery of the ring. White or light-to-dark brown sclerotia (1 to 3 mm in diameter) developed from mycelium on the dead grass. The diseased tissue was disinfested for 1 min in 1% NaOCl and plated on potato dextrose agar amended with 100 mg/l of streptomycin sulphate. Sclerotium rolfsii was consistently isolated from infected plants. Pathogenicity of three isolates obtained from infected plants was confirmed by inoculating healthy D. repens turf (1 m2 plots and three replicates). Inoculum that consisted of wheat kernels infested with mycelium and sclerotia of each isolate was placed on the soil surface. Noninoculated plots served as controls. The inoculation trial was repeated once. Turf was covered with a plastic film for 7 days, kept at temperatures ranging between 22 and 25°C, and watered as needed. Inoculated plants developed symptoms of leaf yellowing within 11 days, soon followed by the appearance of white mycelium and sclerotia, and then eventually wilted. Control plants remained symptomless. Sclerotium rolfsii was re-isolated from inoculated plants. To our knowledge, this is the first report of S. rolfsii on D. repens in Italy. This disease has been reported on kidney weed in several countries such as the United States (3), Brazil (1), and India (2). References: (1) M. Menezes and J. A. A. Lima. Fitossanidade 1:18, 1974. (2) K. Ranganathan and N. Shanmugam. Indian Phytopathol, 27:113, 1974. (3) J. D. Smith et al. Fungal Diseases of Amenity Turf Grasses. E & F.N. Spon, London, 1989.
Root Rot of Black Spruce Caused by Cylindrocladium canadense in Eastern North America
Authors: Vujanovic V. , St-Arnaud M. 
Published: May 2007

During October 2002, symptoms of root rot of black spruce, Picea mariana (Mill.) B.S.P., were observed in the St-Modeste (47°46′N, 69°36′W) conifer nursery (400 km northeast of Montreal, Quebec, Canada). Disease severity was low in the greenhouse-produced mother plants and 1-year-old seedlings and moderate in field-grown 2- and 3-year-old seedlings. A species of Cylindrocladium was isolated on potato dextrose agar from 12 symptomatic seedlings from the greenhouse and 12 from the field. The isolates produced chestnut-colored colonies and chlamydospores, both of which were typical of C. canadense Kang, Crous & Schoch (2). DNA was extracted from representative isolates (MTF 101, MTF 102), and the internal transcribed spacer (ITS) of the rDNA gene was amplified and sequenced (GenBank Accession Nos. AY705980 and AY705981). There was a 99% match with a sequence of C. canadense (GenBank Accession No. AF348256). However, there was approximately 10% divergence with the ITS sequence of C. floridanum (GenBank Accession No AF307343). MTF101 and MTF102 were pathogenic on black spruce seedlings when fungal suspension (106 CFU/ml) was added to germinating seeds in petri plates or infiltrated into roots of 2-week-old seedlings growing in sterilized, moist, sandy soil in the greenhouse. Within 3 weeks, inoculated seedlings exhibited typical root necrosis, while control seedlings were symptomless. C. canadense was reisolated only from symptomatic seedlings. The occurrence of C. canadense in eastern North America has significant implications for forestry regeneration. Previously, only C. floridanum had been reported as pathogenic in the St-Modeste nursery and in eastern North America(1). References: (1) R. C. Hamelin et al. Appl. Environ. Microbiol. 62:4026, 1996. (2) J. C. Kang et al. Syst. Appl. Microbiol. 24:206, 2001.
Nicotiana occidentalis: A New Herbaceous Host for Blueberry scorch virus
Authors: Lowery D. T. , French C. J. , Bernardy M. 
Published: May 2007

Blueberry scorch virus(BlScV) is a carlavirus that causes a serious disease of blueberries (Vaccinium corymbosum L.) in North America (2). In aphid-transmission studies of BlScV using blueberry as host and test species, we found the rate of transmission to be low, and a lengthy incubation period was required before BlScV could be detected. For sequencing studies, RNA extraction from blueberry using standard methods was unreliable and inefficient. These problems prompted a search for alternate hosts. Of 12 herbaceous hosts screened for BlScV transmission using the blueberry aphid, Ericaphis fimbriata Richards, with mechanical transmission, only Nicotiana occidentalis (Wheeler) became infected. After 3 to 4 weeks, infection of N. occidentalis with BlScV resulted in mild symptoms that included pronounced leaf twisting and swollen leaf veins. Infection with BlScV was confirmed using a double-antibody sandwich enzyme-linked immunosorbent assay (DAS-ELISA) kit (Agdia Inc., Elkhart, IN), polyclonal antibodies to BlScV from the antiserum collection at the Pacific Agri-Food Research Center, Summerland, British Columbia, Canada, and reverse transcription-polymerase chain reaction (RT-PCR). Forward (5′-NTAAACACTCCCGAATATAC-3′) and reverse (5′-CAGATTGCTTATCCGGCTTC-3′) primers were designed with the published sequence of BlScV isolate NJ-02 (GenBank Accession No. NC003499). An amplicon of the expected size was generated and sequenced. BLAST analysis indicated that the nucleotide sequence of the amplified fragment was 87% identical to the corresponding sequence in NJ-02 (1). N. occidentalis was readily infected with BlScV following aphid or mechanical inoculations from blueberry. With E. fimbriata as the aphid vector, the transmission rate from blueberry to N. occidentalis was approximately 26%, compared with 70% for mechanical inoculations. Mechanical transfer of BlScV between infected N. occidentalisplants resulted in a 100% transmission rate. Recently, with N. occidentalis, we have completely sequenced two strains of BlScV from British Columbia, Canada and identified several aphid vector species. The identification of N. occidentalis as an herbaceous host of BlScV greatly facilitates future studies on the virus. References: (1) T. D. Cavileer et al. J. Gen. Virol. 75: 711, 1994. (2) R. R. Martin and P. R. Bristow. Phytopathology 78:1636, 1988.
First Report of Soybean Rust Caused by Phakopsora pachyrhizi on Dry Beans in South Africa
Authors: du Preez E. D. , van Rij N. C. , Lawrance K. F. , Miles M. R. , Frederick R. D. 
Published: May 2007

During April 2004, a 150-m2 dry bean (Phaseolus vulgaris) plot growing adjacent to rust-infected soybean (Glycine max) at Cedara Agricultural Research Farm (29°32′S 30°16′E) was observed to be infected with two distinct rust types. Common bean rust (caused by Uromyces appendiculatus) with reddish brown uredinia and black telia was readily identified. A second rust with smaller sporulating uredinia (1.0 to 1.5 mm2), which were gray in appearance, was also found. Visual rust severity on the dry bean plants, which were in mid pod-fill, was high (approximately 30 to 40% disease incidence). Twenty plants were examined and observed to be infected with both rusts. With microscopic examination of no fewer than 20 leaves per plant, the urediniospores from the smaller lesions were determined to be morphologically similar to Phakopsora pachyrhizi (3). Real-time fluorescent polymerase chain reaction assays on six leaves and sequence analysis of the nuclear ribosomal internal transcribed spacer region 2 (1) verified the identity of the urediniospores as P. pachyrhizi. Although P. vulgaris is a known host of P. pachyrhizi, to our knowledge this is the first time since the arrival of soybean rust in 2001 that P. pachyrhizi has been observed on an alternate host plant in South Africa (2). Since dry beans are grown all year in frost-free areas, the implications are that dry beans may serve as an important overwintering host and source of inoculum for seasonal soybean rust outbreaks. References: (1) R. D. Frederick et al. Phytopathology 92:217, 2002. (2) Z. A. Pretorius et al. Plant Dis. 85:1288, 2001. (3) J. B. Sinclair and G. L. Hartman. Soybean Rust. Pages 25–26 in: Compendium of Soybean Diseases, 4th ed. G. L. Hartman et al. eds. The American Phytopathological Society, St. Paul, MN, 1999.
First Report of Soft Rot Caused by Sclerotinia sclerotiorum on Borage in North Dakota
Authors: Bradley C. A. , del Río L. E. , Chesrown C. D. , Johnson B. L. 
Published: May 2007

Borage (Borago officinalis) is an oilseed crop that is being evaluated as an alternative crop in North Dakota. During September 2004, borage plants in a field in Cass County, North Dakota were dying from a watery soft rot. The main stems and lateral branches were affected, and affected plants were usually completely lodged and prostrate. Dead plants had bleached and shredded stems with black sclerotia (9.1 ± 3.0 × 2.6 ± 0.5 mm) inside the pith and on the epidermis. At the time of observation, borage plants were flowering and forming pods and seed. Approximately 60% of the plants were visually affected by the watery soft rot. Sclerotia were collected from diseased plants, soaked in a 0.5% NaOCL solution for 30 s, air dried, and placed in petri dishes containing potato dextrose agar (PDA). A fungus grew from the plated sclerotia that subsequently produced white mycelium and black sclerotia (4.8 ± 1.2 × 2.5 ± 1.0 mm), which is characteristic of Sclerotinia sclerotiorum (Lib.) de Bary (3). To confirm pathogenicity, borage plants were inoculated in the greenhouse with a S. sclerotiorum isolate from field-infected borage. Thirteen borage plants were grown from seed in the greenhouse under natural sunlight at a temperature range of 24 ± 3°C. When plants were at the four-leaf stage (approximately 16 cm high), the second leaf was excised from each plant with the petiole remaining on the plant. The leafless petioles were inoculated using a method previously described (2). Petioles of 10 plants were inoculated with PDA containing mycelium of the S. sclerotiorum borage isolate, while petioles of five plants were inoculated with PDA to serve as a control. Three days after inoculation, plants inoculated with the S. sclerotiorum borage isolate were beginning to wilt and 5 days after inoculation, these plants were completely wilted and prostrate, similar to observations made on field-infected plants. Sclerotia collected from the diseased, inoculated plants were placed on PDA, and S. sclerotiorum was successfully recovered. Control plants inoculated with PDA did not show any disease symptoms. Other plant genera in the Boraginaceae are known hosts of S. sclerotiorum (1); however, to our knowledge, this is the first report of borage as a host. References: (1) G. J. Boland and R. Hall, Can. J. Plant Pathol. 16:93, 1994. (2) L. E. del Río et al. (Abstr.) Phytopathology 90(suppl.):S176, 2000. (3) D. L. Tourneau, Phytopathology 69:887, 1979.
First Report of Leaf Spot on Japanese Plum Caused by an Alternaria sp. in Korea
Authors: Kim Youngjun , Lee Hyang Burm , Yu Seung Hun 
Published: May 2007

Japanese plum (Prunus salicina Lindley) is a deciduous tree in the family Rosaceae. In Korea, this plant is widely distributed in orchards as an important stone fruit as well as in gardens as an ornamental tree because of their abundant white blossoms. Every September to November since 2001, leaf spots were observed on Japanese plum in a garden in Cheongyang, Chungnam District, Korea. Early symptoms consisted of small, brown spots that were 2 to 5 mm in diameter. Later, the leaf lesions became circular or irregular, dark brown, expanded to 15 mm in diameter, and resulted in discoloration with necrosis on twisted leaves that was followed by defoliation. In November, older lesions sometimes appeared blackish brown as sporulation occurred on the lesions. The causal fungus was isolated from diseased leaves and cultured on potato dextrose agar. A culture has been placed in the CABI Herbarium (IMI Accession No. 387139). Conidial dimension averaged 34 × 12 μm. On the basis of morphological characteristics of conidia and conidiophores, the causal fungus was identified as a small-spored species of Alternaria as described by E. G. Simmons (1). Pathogenicity tests were conducted by inoculating slightly wounded and nonwounded leaves with a conidial suspension adjusted to 1 × 106 conidia/ml. Four leaves per each experiment were either wounded or not and inoculated with a spore suspension. The eight leaves were placed in a moist chamber at 25°C. After 6 to 10 days, small brown spots appeared on 87% of the wounded and nonwounded leaves. Control leaves sprayed with distilled water did not develop any symptoms. The causal fungus was consistently reisolated from the leaf spots. Results from pathogenicity tests were similar in a repeated test. It is possible that small-spored Alternaria spp. isolates are host specific (2). Eight Alternaria spp., including A. alternata, A. tenuis, A. tenuissima, and A. citri, have been found to cause black spot on fifteen Prunus spp. in China, Japan, Hong Kong, Libya, Mexico, Australia, and the United States (2). Further studies on the host-specific toxin production, geographical distribution, and host ranges for the species of Alternaria isolated from Japanese plum are in progress. To our knowledge, this is the first report of leaf spot on Japanese plum (P. salicina) caused by a small-spored Alternaria sp. in Korea. References: (1) E. G. Simmons. Mycotaxon 55:79, 1995. (2) K. Inoue and H. Nasu. J. Gen. Plant Pathol. 66:18, 2002.
Texas Has a New Pathotype of Peronosclerospora sorghi, the Cause of Sorghum Downy Mildew
Authors: Isakeit T. , Jaster J. 
Published: May 2007

Three pathotypes of Peronosclerospora sorghi were known to occur in Texas as of 1980, with pathotype 3 (P3) predominant on sorghum (Sorghum bicolor) grown in the Upper Coast area. Following the use of hybrids resistant to P3, combined with metalaxyl or mefenoxam seed treatment, sorghum downy mildew (SDM) became a minor disease in Texas until the occurrence of a widespread outbreak caused by a P3 strain resistant to metalaxyl and mefenoxam in Wharton County in 2001 (2). During July 2004, <1% of plants in a commercial field in Wharton County planted to two Pioneer Brand P3-resistant hybrids had white stripes on the leaves and leaf shredding typical of systemic SDM. To obtain inoculum for pathogenicity studies, several infected plants were removed from the field and transplanted to pots for growth in a greenhouse. Systemically infected leaves suitable for inoculum production subsequently developed from tillers. Conidia were collected from leaves using a tiered temperature system (1). One-week-old seedlings of 10 sorghum lines used as pathotype differentials for Texas were sprayed until runoff with a conidial suspension (8 × 104 per ml) and incubated for 24 h at 20°C and 100% relative humidity. Seedlings were grown for 6 days in the greenhouse and then incubated overnight at 20°C and 100% relative humidity to promote sporulation of lesions, while systemic symptoms were evaluated after an additional 2 weeks in the greenhouse. There were 10 seeds planted per replicate and four replicates per line. The experiment was repeated once. Sporulation occurred on 54 and 64% of plants, and systemic symptoms on 53 and 82% of plants of P3-resistant line SC155 in two experiments, respectively. There were no local lesions or systemic symptoms on SC155 plants inoculated with several P3 isolates. Lines SC414-12E, QL3-India, 82BDM499, and 85EON495, which are resistant to P3, were also resistant to this isolate (i.e., no local lesions or systemic symptoms). Lines RTx2536, RTx430, CS3541, RTx7078, and SC170-6-17, which are susceptible to P3, were also susceptible to this isolate (54 to 100% incidence of systemic symptoms). An experiment (repeated once) that compared the reaction of this new pathotype on metalaxyl-treated and nontreated seed of a P3-resistant hybrid and a P3-susceptible hybrid, with reactions of metalaxyl-resistant P3 isolate and a metalaxyl-sensitive P3 isolate, showed that this pathotype, in addition to overcoming the genetic resistance, was also fungicide resistant. The pathogenicity of this new pathotype to other commercial P3-resistant hybrids is not yet known. There was no yield loss associated with this outbreak. However, the presence of a new pathotype, in combination with fungicide resistance, could lead to further outbreaks of SDM in the Upper Coast of Texas with the potential for yield loss. References: (1) J. Craig. Plant Dis. 71:356, 1987. (2) T. Isakeit et al. (Abstr.) Phytopathology 93:S39, 2003.
First Report of Perithecia of Phaeoacremonium viticola on Grapevine (Vitis vinifera) and Ash Tree (Fraxinus latifolia) in California
Authors: Eskalen A. , Rooney-Latham S. , Gubler W. D. 
Published: May 2007

Esca and Petri diseases on grapevine are caused by Phaeomoniella chlamydospora and species of Phaeoacremonium including P. aleophilum, P. viticola, P. angustius, P. parasiticum, P. inflatipes, P. rubrigenum, and P. mortoniae. The teleomorphs of P. aleophilum and P. mortoniae have been recently confirmed as Togninia minima(Tul. & C. Tul.) Berl. (2,3), and T. fraxinopennsylvanica (Hinds) Hausner, Eyjólfsdóttir & J. Reid, respectively (1,2,3). Teleomorphs of other Phaeoacremonium spp. have not been identified, although molecular data suggests that Phaeaoacremonium spp. are linked to the genus Togninia. Naturally infected vineyards with symptoms of esca disease were surveyed during the summer and fall of 2004. Samples were collected from declining ash trees surrounding the vineyards, as well as from symptomatic grapevine trunks, cordons, and spurs. Samples were processed as previously described (1). Sterile isolations were also made from symptomatic vascular tissue of the samples and cultured on potato dextrose agar (PDA)-tet medium. Perithecia were found on the surfaces of old pruning wounds and in the cracks of cordons and trunks on Vitis vinifera cvs. Thompson Seedless, Riesling, and Cabernet Sauvignon. Perithecia were observed on grapevines in vineyards in six of nine counties, viz. Yolo, Mendocino, El Dorado, Tulare, Madera, and Sonoma. Perithecia were also observed in dead vascular tissue of declining ash tree branches (Fraxinus latifolia) located in the vicinity of vineyards in Sonoma and Yolo counties. Perithecia were black, globose to subglobose, ranging from 160 to 215 μm in diameter, and were both embedded in and superficial on the wood tissue. Neck lengths ranged from 55 to 340 μm. The asci were hyaline, clavate, and ranged in size from 12.5 to 19.5 × 3.2 to 4.5 μm. Ascospores were hyaline, ellipsoid to allantoid, and ranged in size from 3.1 to 4.1 × 1.8 to 2.1 μm. Morphologically these perithecia resemble those of Togninia spp. When plated onto PDA-tet medium, ascospores formed colonies of P. viticola after 10 days of incubation at room temperature. Additionally, P. viticola was isolated from vascular tissue of the collected plant specimens. To our knowledge, this is the first time that P. viticola has been linked to a sexual state. References: (1) A. Eskalen et al. Plant Dis. 89:528, 2005. (2) L. Mostert et al. Mycologia 95:646, 2003. (3) S. Rooney-Latham. Plant Dis. 89:177, 2005.
First Report of Xylella fastidiosa Infecting Citrus in Costa Rica
Authors: Aguilar E. , Villalobos W. , Moreira L. , Rodríguez C. M. , Kitajima E. W. , Rivera C. 
Published: May 2007

Citrus variegated chlorosis (CVC) is an important disease mainly of sweet orange (Citrus sinensis (L.) Osbeck) cultivars. It was first described in Brazil in the state of Sā Paulo in 1987 (4). The disease has spread to all Brazilian states that grow citrus and is affecting more than one-third of the orange trees grown in Brazil. CVC is caused by Xylella fastidiousa, a xylem-limited, gram-negative bacterium. During the last 4 years, symptoms including leaf interveinal chlorosis, stunting, canopy dieback, and hard and undersized fruits, similar to those caused by CVC (3), appeared in sweet orange trees used as shade plants for coffee plantations and as fence posts in Costa Rica. Necrotic lesions on the abaxial side of the leaves as reported in Brazil were rarely observed. Leaf petiole samples from 25 symptomatic sweet orange trees reacted positively with a X fastidiosa-specific antiserum (AGDIA Inc., Elkart, IN) in a double-sandwich antibody enzyme-linked immunosorbent assay (DAS-ELISA). A fastidious, gram-negative bacterium identified as X. fastidiosa using DAS-ELISA was isolated on perwinkle wilt (PW) medium plates (1) from citrus stems showing CVC symptoms, but not from asymptomatic trees. The isolated colonies were circular and opalescent with diameters of 2 to 3 mm and were clearly visible within 6 to 7 days after streaking. Petiole sections from symptomatic plants observed with scanning electron microscopy showed rod-shaped bacteria with rippled cell walls tightly packed in xylem vessels, as described for X. fastidiosa previously (2), and with transmission electron microscopy, the bacteria were morphologically similar to those reported previously for CVC (2). To our knowledge, this is the first report of X. fastidiosa associated with citrus in Costa Rica. References: (1) M. J. Davis et al. Curr. Microbiol. 6:309, 1981. (2) J. S. Hartung et al. Phytopathology 84:591, 1994. (3) R. F. Lee et al. Summa Phytopathol. 19:123, 1993. (4) V. Rossetti et al. 1990, C.R. Acad. Sci. (Paris) 310:345–349.
First Report of Downy Mildew of Arugula Caused by Peronospora parasitica in Argentina
Authors: Romero A. M. , Zapata R. 
Published: May 2007

Acreage of arugula (Eruca sativa), a crucifer used as a component of green salad mixes, has increased recently in Argentina. During 2004, a foliar disease affected commercial crops in Pilar (northeast of Buenos Aires Province). Arugula plants were affected from the seedling stage to harvest. Severely diseased plants were unmarketable and not harvested. Sunken, round, necrotic lesions (1 to 4 mm in diameter) were observed on the cotyledons. Diseased leaves had irregular, necrotic lesions (2 to 3 mm in diameter) that sometimes became confluent, forming a linear pattern. Necrotic tan patches developed on older leaves. Lesions on the abaxial surface appeared depressed and a gray mold, a typical sign of a downy mildew, was visible. Sporangiophores had dichotomous branches ending in slender curved tips. Sporangia were ovoid with a mean length of 20 μm (17.8 to 22.1 μm) and a mean width of 16 μm (14 to 18.2 μm). Pathogenicity tests were conducted by placing excised diseased leaves onto healthy 30-day-old arugula plants (1). Inoculated plants were placed in plastic bags, previously sprayed with water, for 48 h and maintained in the greenhouse thereafter. Downy mildew symptoms and signs that were similar to those observed in the fields developed 10 days after inoculation. The pathogen was identified as Peronospora parasitica (2). To our knowledge, this is the first report of P. parasitica on arugula in Argentina. References: (1) S. T. Koike. Plant Dis. 82:1063, 1998. (2) W. D. Yerkes and C. G. Shaw. Phytopathology 49:499, 1959.