bluuebunny/crossref_metadata_2025_split huggingface dataset:
First Report of Puccinia sorghi Virulent on Sweet Corn with the Rp1-D Gene in Florida and Texas
Authors: Pate M. C. , Pataky J. K. , Houghton W. C. , Teyker R. H. 
Published: May 2007

For the past 15 years, the Rp1-D gene has controlled common rust on sweet corn in North America. In August and September 1999, isolates of Puccinia sorghi were collected from Rp1-D sweet corn hybrids in Illinois, Wisconsin, Minnesota, Michigan, and New York. This was the first widespread occurrence in the continental United States of P. sorghi virulent on the Rp1-D gene (1). Isolates of P. sorghi collected from Los Mochis, Mexico, in March 2000 had a pattern of virulence similar to the pattern for the isolates collected in the Midwest in 1999 (2). In April and May 2000, small uredinia were observed on Rp1-D sweet corn in Florida and Texas. In Florida, isolates were collected from six different locations within a 13-km radius near Belle Glade. Three isolates were collected each from Rp1-D and non-Rp sweet corn hybrids. Isolates also were collected from two Rp1-D sweet corn hybrids and a non-Rp sweet corn hybrid near Hondo, TX. Inocula of isolates were increased through one uredinial generation in the greenhouse. Several 1-cm2 pieces of leaf tissue with sporulating uredinia were placed in 15 ml of a solution of water and Tween 20. This inoculum was placed in whorls of five two-leaved seedlings of a susceptible hybrid, ‘Primetime.’ Urediniospores from newly formed uredinia were collected 10 days later and used as inocula to assay each isolate. Two isolates from Florida (one each from an Rp1-D and a non-Rp hybrid) were assayed on a non-Rp susceptible check, 20 different single Rp genes, and nine compound Rp genes. Other isolates were assayed on two replicates of a non-Rp susceptible check, a source of Rp1-D, and five single Rp genes that were effective against the isolates collected from the Midwest in 1999 and from Mexico in 2000. Each experimental unit consisted of five plants grown in 10-cm-diameter pots. Plants at the two-leaf stage were inoculated three times within 5 days by filling whorls with a urediniospore suspension. Rust reactions were rated 10 days after the final inoculation. Isolates collected in Florida from non-Rp hybrids were avirulent on Rp1-D but those collected in Texas from non-Rp hybrids were virulent on Rp1-D. Isolates collected in Florida and Texas from Rp1-D hybrids had a similar pattern of virulence as isolates collected from the Midwest in 1999 and from Mexico in March 2000; that is, effective single Rp genes included Rp1-E, Rp-G, Rp1-I, and Rp1-K. A source that we previously believed was Rp1-L now appears to be Rp-G. These are the first reports from Florida and Texas of P. sorghi virulent on Rp1-D, and they are the first occurrences of virulence against Rp1-D in the continental U.S. in 2000. Apparently, P. sorghi with virulence against Rp1-D has become established in an area where common rust inocula for North America overwinters. References: (1) J. K. Pataky and W. F. Tracy. Plant Dis. 83:1177, 1999. (2) J. K. Pataky et al. Plant Dis. 84:810, 2000.
First Report of Downy Mildew Caused by Peronospora lamii on Salvia splendens and Salvia coccinea
Authors: Holcomb G. E. 
Published: May 2007

Angular chlorotic spots were observed on adaxial leaf surfaces of Salvia splendens (scarlet sage cvs. Empire Purple, Empire White, Red Pillar, and Red Hot Sally) and S. coccinea (scarlet or Texas sage cv. Lady in Red) in early May in Baton Rouge area nurseries. Leaf spots sometimes became necrotic and resulted in leaf drop. Abaxial leaf surfaces contained scattered patches of white mycelia with brown spores. Microscopic examination of mycelia revealed irregular dichotomously branched conidiophores with pointed tips and brown oval conidia. Conidiophores averaged 485 × 9 µm and conidia averaged 21 × 18 µm (16 to 26 × 15 to 23 µm) in dimensions. The fungus was identified as Peronospora lamii A. Braun (= P. swinglei Ellis & Everh.) based on these characters and its known occurrence on Salvia spp. and five other genera in the family Lamiaceae (2). Pathogenicity tests were performed by washing conidia from infected leaves into distilled water and mistinoculating S. coccinea cv. Lady in Red and S. splendens cv. Empire Purple with 50,000 spores/ml. Plants were held in a dew chamber at 20°C for 3 days, then moved to a greenhouse where temperatures ranged from 18 to 32°C. Typical angular chlorotic leaf spots developed on inoculated plants within 6 to 8 days and noninoculated plants remained healthy. The fungus did not sporulate under these greenhouse temperatures, but infected leaves that were removed and placed in a moist chamber at 25°C produced conidiophores and brown conidia typical of P. lamii within 2 to 3 days. P. lamii has been reported previously on S. officinalis (3) and S. reflexa (1) in the United States. This is the first report of downy mildew on S. coccinea and S. splendens. Appearance of the disease in retail nurseries that obtained plants from out of state (Arkansas) suggests a widespread occurrence of the disease on these host plants. References: (1) D. F. Farr et al. 1989. Fungi on Plants and Plant Products in the United States. American Phytopathological Society, St. Paul, MN. (2) S. M. Francis. 1981. Peronospora lamii. Descriptions of Pathogenic Fungi and Bacteria No. 688. Commonwealth Mycological Institute, Kew, England. (3) R. T. McMillan and W. R. Graves. Plant Dis. 78:317, 1994.
Evidence for Association of a Viroid with Tapping Panel Dryness Syndrome of Rubber (Hevea brasiliensis)
Authors: Ramachandran P. , Mathur S. , Francis L. , Varma A. , Mathew J. , Mathew N. M. , Sethuraj M. R. 
Published: May 2007

Tapping panel dryness (TPD) is one of the most destructive maladies affecting rubber plantations and is becoming a matter of serious concern. Reduced latex yield leading to total drying of the tapping panel is the obvious symptom. The cause of TPD syndrome is unknown but has been mostly attributed to abiotic causes. In India, the high yielding commercial clone RRII 105 is affected by TPD, leading to enormous losses. We have observed that TPD-affected trees show symptoms of bark scaling, cracking, drying, necrotic streaking, and browning of internal bark leading to the decay of internal tissues. Often prominent abnormal bulges on the lower part of tree trunks occur where the first panel begins to dry. Investigations on TPD-affected rubber samples did not reveal the association of fungus, bacterium, virus, or a protozoan. Total nucleic acid extracts purified from leaf and bark tissues of affected samples and analyzed by polyacrylamide gel electrophoresis under denaturing conditions of low salt and high temperature showed the presence of nucleic acids similar in electrophoretic mobility to low molecular weight (LMW) RNA, of ~359 nucleotides such as potato spindle tuber viroid (PSTVd). The LMW nucleic acid detected from TPD-affected samples was found to be RNA based on its sensitivity to RNase and insensitivity to DNase, phenol, and heat treatments. The LMW RNA was purified and cloned in a pUC 19-derived vector by using primers specific to PSTVd (1). The cloned DNA, when random labeled and used as probe reacted specifically to nucleic acid extracts from TPD-affected rubber trees but not from healthy tissue in dot-blot hybridization assays. Based on the above findings, a viroid etiology for TPD syndrome is proposed. Reference: (1) R. A. Owens, A. T. Candresse, and T. O. Diener. Virology 175:238, 1990.
First Report of Sugarcane yellow leaf virus in Peru
Authors: Alegría O. M. , Chatenet M. , Girard J. C. , Saldarriaga S. A. , Nuget A. , Rott P. 
Published: May 2007

Two sugarcane cultivars, H 50-7209 and H 32-8560, have exhibited unusual, severe leaf yellowing for more than 18 years at Agro Industrial Paramonga S.A. (AIPSA) in Peru. In 1999, these varieties occupied about 4,600 ha (74% of the cultivated area), and almost all fields showed these symptoms. Symptoms first appear on the upper third of the leaf blades, which turns light green to light yellow in young canes up to 6 to 8 months of age. Between 10 and 16 months of age, the symptoms are visible on the spindle and first to third visible dewlap leaves. Tips and margins of older leaves become necrotic, and leaves can turn completely necrotic as the necrosis progresses down the leaves. The abaxial surface of leaf midribs is rarely bright yellow, which differs from the characteristic symptom of yellow leaf syndrome caused by the Sugarcane yellow leaf virus (ScYLV) (1). The most severe symptoms occur when the leaves of stalks that flower turn completely yellow and die. Samples from 98 plants exhibiting different types of yellowing were collected from six commercial fields of cultivars H 50-7209 and H 32-8560 and the germ plasm collection (cultivars PCG 59-1609, Trojan, CP 48-103, CP 72-2086, Q 87, and PR 908) at Paramonga. Tissue blot immunoassay was used to detect ScYLV in the midrib of the top visible dewlap leaf using antiserum provided by B. E. L. Lockhart (University of Minnesota) (2). ScYLV was detected in all 49 commercial field samples and in 35 out of 49 germ plasm samples. All six cultivars of the germ plasm collection were found to be infected, but ScYLV was detected in only a few leaves of Trojan and CP 72-2086. Eighteen cuttings from diseased stalks of cultivars H 50-7209 and H 32-8560 were grown in a greenhouse in Montpellier, France. Yellowing of the underside of the midribs and of the leaf tips appeared after 3 months in cultivar H 50-7209 but only after 9 months in cultivar H 32-8560. At 9 months, the top leaf with a visible dewlap and the four leaves immediately below it of cultivar H 50-7209 exhibited severe yellowing. Reverse transcription polymerase chain reaction with specific ScYLV primers, provided by M. S. Irey (U.S. Sugar Corp., Clewiston, FL) were used to detect ScYLV in the top visible dewlap leaf (1), and ScYLV was found in all nine samples taken from 6-month-old plants of the two cultivars. This is the first report of ScYLV in Peru. References: (1) J. C. Comstock et al. Sugar Cane 4:21, 1998. (2) S. Schenck et al. Sugar Cane 4:5, 1997.
First Report of Leaf Blight of Dianthus chinensis Caused by Rhizoctonia solani
Authors: Holcomb G. E. , Carling D. E. 
Published: May 2007

Dianthus chinensis (rainbow pink) is a popular seasonal bedding plant for the Gulf Coast of the United States and is primarily grown during the fall, winter, and early spring months. In August 1999, diseased plants were observed in a Baton Rouge, LA, propagation nursery with irregularly oval, tan leaf spots 3 to 10 mm in diameter. Heavily infected leaves became blighted and were killed, but plants survived and roots, crowns, and flowers were not affected. Infected leaf samples were surface-disinfected for 1 to 3 min in 70% ethyl alcohol, blotted dry, and sections were placed on 2% acidified water agar. A fungus that was identified as Rhizoctonia solani, and belonging to anastomosis group (AG)-1 IB, was consistently isolated from infected leaves. Inoculum was prepared by blending one 7-day-old plate culture, grown on acidified potato-dextrose agar, in 100 ml distilled deionized water. Pathogenicity tests were performed by dripping inoculum from a 10-ml pipette on leaf surfaces of healthy rainbow pink plants. Inoculated and noninoculated plants were held in a dew chamber at 26°C for 2 to 3 days and then removed to a greenhouse where temperatures ranged from 25 to 32°C. Inoculated plants developed water-soaked spots after 2 to 3 days that turned tan and became necrotic 5 to 10 days later. These symptoms were like those observed on the original diseased plants. R. solani was reisolated from inoculated plants, and noninoculated plants remained healthy. Although R. solani has been reported previously as a root and stem pathogen of D. chinensis (1), this is the first report of leaf blight disease caused by this fungus. Reference: (1) D. F. Farr et al. 1989. Fungi on Plants and Plant Products in the United States. American Phytopathological Society, St. Paul, MN.
First Report of Colletotrichum gloeosporioides on Chinese Rose in Argentina
Authors: Rivera M. C. , Wright E. R. , Carballo S. 
Published: May 2007

Chinese rose (Hibiscus rosa-sinensis L.) is a shrub frequently planted in Argentina. In November 1999, dieback and anthracnose symptoms were detected on stems and leaves of plants cv. Hawaii cultivated in Buenos Aires. Disease prevalence was 50%. Pieces of infected tissues were surface-sterilized for 1 min in 2% NaOCl, plated on potato-dextrose agar and incubated at 24 ± 2°C. The isolate that was consistently recovered from diseased tissues was identified as Colletotrichum gloeosporioides (Penz.) Penz. and Sacc., based on morphological characteristics (1,2). Teleomorph stage was not observed. Inoculation for pathogenicity testing was carried out by spraying a conidial suspension (6.5 × 106 conidia per ml) on plants with previously punctured leaves and pruned stems. Inoculated plants with unwounded tissues, as well as noninoculated controls, were included. Five replications of each treatment were done. Plants were incubated in moist chambers at 24°C. Whitish areas of 0.3 to 0.5 cm diameter surrounded by a purple halo developed on all punctured leaves within 10 days. Stem blight and leaf drop were observed. The center of the lesions was covered by black acervuli 14 days after inoculation. Unwounded and noninoculated controls remained symptomless. The pathogen was reisolated from inoculated leaves, completing Koch's postulates. This is the first report of C. gloeosporioides causing disease on Chinese rose in Argentina. References: (1) J. A. Bailey and M. J. Jeger, eds. 1992. Colletotrichum. CAB International, Surrey, England. (2) B. C. Sutton. 1980. The Coelomycetes. CMI, Kew.
First Report of Sclerotium rolfsii on Catharanthus roseus
Authors: Holcomb G. E. 
Published: May 2007

Wilt, blight, and stem necrosis were observed on Catharanthus roseus (L.) G. Don ‘Mediterranean Deep Rose’ (MDR) plants (Madagascar or rose periwinkle) in August 1999 at Burden Research Plantation in Baton Rouge, LA. MDR was the only prostrate-form cultivar and the only cultivar of 11 that was diseased. Twelve of twenty-four plants of cv. MDR were killed in the trial planting. White mycelia and small (1 mm diameter) light brown sclerotia were present at the base of infected plants. The suspect fungus was isolated consistently on acidified water agar and maintained on acidified potato dextrose agar (APDA). Pathogenicity tests were done by pipetting 1 ml of blended inoculum (contents of one 7-day-old plate culture grown on APDA in 100 ml of deionized water) at the base of nine 15-cm-tall Madagascar periwinkle plants. Inoculated and noninoculated plants were held in a dew chamber for 3 days at 28°C and placed in a greenhouse where temperatures ranged between 25 and 31°C. All inoculated plants showed wilt, blight, and basal stem rot after 3 days and were dead after 10 days. Noninoculated plants remained symptomless. The fungal pathogen was identified as Sclerotium rolfsii Sacc. and was reisolated from inoculated plants. The fungus was previously reported on Lochnera rosea (L.) Rchb. (=C. roseus) from Taiwan (1). This is the first report of the occurrence of S. rolfsii on Madagascar periwinkle in the United States. Reference: (1) K. Goto. Trans. Nat. Hist. Soc. Formosa 23:37, 1933.
First Report of Petunia vein clearing virus in Israel
Authors: Gera A. , Sikron N. , Cohen J. , Zeidan M. 
Published: May 2007

Petunia vein clearing virus (PVCV), a possible member of the cauli-movirus group, was detected in several cultivars of vegetatively propagated petunias grown in commercial nurseries in Israel. Symptoms associated with PVCV infection in petunia cv. Chaplin consisted of stunted young shoots, leaf yellowing, and severe vein clearing. Virus incidence within this cultivar was 40 to 60%. Symptoms were most frequently expressed when plants were subjected to temperatures above 20°C and nutrient deficiencies. The virus was transmitted to petunia only by grafting, however, not by aphids or mechanical inoculation. Leaf dip preparations and thin sections of leaf tissue were analyzed by transmission electron microscopy. Spherical virus particles (45 to 50 nm diameter) were observed in samples from symptomatic petunia plants. In immunoelectron microscopy, the virus particles produced a distinct pattern with the specific antiserum against PVCV provided by D. Lesemann (Biologische Bundesanstalt, Braunschweig, Germany). Infection with PVCV also was confirmed by polymerase chain reaction with total nucleic acid extract preparations. Two primer pairs—5′-GAGGTCAGAGCAAGTCAGAGG-3′ (nucleotides 4339 to 4359) and 5′-GTAATGATTTGACTTGTTGAG-3′ (nucleotides 5055 to 5075)—were designed to flank a 736-bp sequence in the RNA-dependent RNA polymerase gene of the PVCV genome (GenBank Accession no. U95208). A DNA fragment of the predicted size was visualized in agarose gels. Authenticity of the amplified DNA fragment was confirmed by restriction analysis. The virus has been detected in the past in Germany (1) and recently in the United States (2). This is the first report of PVCV in commercial nurseries in Israel. References: (1) D. Lesemann and R. Casper. Phytopathology 63:1118, 1973. (2) B. Lockhart and D. Lesemann. Plant Dis. 82:262, 1998.
Expansion of the European Race of Gremmeniella abietina in Newfoundland, Canada
Authors: Harrison K. J. , Hurley J. E. , Warren G. R. , Laflamme G. 
Published: May 2007

Since its detection on ornamental pines in St. John's, Newfoundland, Canada, in 1979 (3), the European race causing Scleroderris canker (Gremmeniella abietina (Lagerb.) Morelet) has been detected throughout the Avalon Peninsula at the eastern end of the province. A quarantine was established on the Avalon Peninsula in 1980 to reduce the risk of introducing the disease to the natural red pine (Pinus resinosa Aiton) stands on the remainder of the island. Scots, red, and jack pines were examined at 34 locations in Newfoundland in 1998 and 1999. Infected trees were detected at four locations outside the quarantine zone. In the fall of 1998, the disease was found in plantations at three locations outside the quarantine zone: on Scots pine (P. sylvestris L.) at Bonavista and Catalina (≈135 km north-northeast of the quarantine) and on jack pine (P. banksiana Lamb.) and Scots pine at Sunnyside on Trinity Bay (≈45 km northwest of the quarantine). In 1999, the disease was detected at a fourth location on planted Scots pine in Come By Chance, near the Sunnyside location. Cultures of the pathogen were recovered from branch samples collected at each location and submitted for race determination at the Laurentian Forestry Centre, Sainte-Foy, QB. All isolates were determined based on the polymerase chain reaction diagnostic technique (1) to be the European race of G. abietina. This is a significant range extension from that reported by Laflamme et al. (2). The infected trees originated from the former Back River tree nursery at Salmonier Line that provided planting stock for a provincial reforestation program between 1937 and 1952. Evidence suggests that this nursery was the source of infected stock for plantations at nine locations within the Avalon Peninsula quarantine zone and the four new locations detected during the 1998 and 1999 surveys. This is similar to the pattern described for other nurseries in eastern Canada and the United States (2). The presence of the European race of G. abietina outside of the Avalon Peninsula increases the risk that the disease will become established in the rare natural red pine stands on the rest of the island of Newfoundland. References: (1) R. C. Hamelin et al. Appl. Environ. Microbiol. 59:1752, 1993. (2) G. Laflamme et al. For. Chron. 74:561, 1998. (3) P. Singh et al. Plant Dis. 64:1117, 1980.
First Report of Pseudomonas syringae pv. tomato Race 1 on Tomato in California
Authors: Arredondo C. R. , Davis R. M. 
Published: May 2007

Symptoms of bacterial speck have occurred sporadically in California since 1993 on tomato (Lycopersicon esculentum) cultivars that possess the PTO gene for resistance to Pseudomonas syringae pv. tomato race 0. In 1998, the disease was found on numerous cultivars resistant to race 0 in fields throughout the Sacramento Valley. In several fields, it caused severe defoliation of tomato seedlings. Symptoms included dark brown to black leaf and stem lesions surrounded by yellow halos. Seven isolates were identified as P. syringae pv. tomato based on analysis of whole cell fatty acids (MIDI, Newark, DE; similarity indices of 0.746 to 0.710), carbon utilization profile (Biolog, Hayward, CA; similarity indices of 0.556 to 0.840), and LOPAT results: levan production (+), oxidase reaction (-), potato soft rot (-), arginine dihydrolase production (-), and tobacco hypersensitivity (+) (2). The isolates were identified as race 1 by inoculating greenhouse-grown tomato plants of cv. Ontario 7710, which possesses the PTO gene, and cv. H1916, which is susceptible to both known races of P. syringae pv. tomato. At least eight plants of each cultivar were inoculated with each isolate. Plants were inoculated by spraying leaves with a bacterial suspension mixed with Carborundum or puncturing leaves with needles dipped in the bacterial suspension (107 cells per ml). Controls were inoculated with water. All plants inoculated with the bacteria developed speck symptoms in 6 days. The bacteria were reisolated from all inoculated plants and confirmed as strains of P. syringae pv. tomato. This is the first documentation of P. syringae pv. tomato race 1 in California. This race was previously reported in Canada in 1986 (1). References: (1) M. B. Lawton and B. H. MacNeill. Can. J. Plant Pathol. 8:85, 1986. (2) R. A. Lelliott et al. J. Appl. Bacteriol. 29:470, 1966.
First Report of Trunk Blight and Canker of Morus alaba var. pendula Caused by Fusarium lateritium f. sp. mori in Hungary
Authors: Vajna L. 
Published: May 2007

Morus alba var. pendula (mulberry) is a favorite ornamental tree in Hungary. In 1998 and 1999, a canker disease was observed on this species in a western Hungarian ornamental tree nursery in Köszeg. Bark necrosis and cankers exposing the xylem were observed on the trunks of 1-, 2-, and 3-year-old trees. Pink sporodochia 200 to 400 μm in diameter were found in the necrotic bark. The fungus associated with the trunk cankers was identified as Fusarium lateritium Nees:Fr. f. sp. mori (Desmaz.) Matuo & K. Sato (1) from sporodochia and fungal isolates recovered from necrotic tissues. Isolations on potato dextrose agar yielded white colonies with a slight pink discoloration. Radial colony growth rate at 22°C and 12 h of light daily was 5 mm. Macroconidia were typical of F. lateritium, with three to eight septa. Microconidia were not observed. Intercalary chlamidospores (7 to 8 μm) rarely formed. Pathogenicity of the fungus was confirmed with a monoconidial culture. Three-year-old mulberry tree stems were inoculated with mycelial agar plugs. After 10 days, sunken necrotic lesions with a brownish discoloration, similar to naturally occurring cankers, developed. F. lateritium was successfully recovered from these lesions. No necrosis developed around control wounds. Mulberry Fusarium stem blight and canker is found in many temperate regions (2) but was not recorded as a disease of M. alba var. pendula in nurseries. This is the first record of the disease in Hungary. References: (1) C. Booth. 1971. The Genus Fusarium. Commonwealth Mycological Institute, Kew, England. (2) D. F. Farr et al. 1989. Fungi on Plants and Plant Products in the United States. The American Phytopathological Society, St. Paul, MN.