bluuebunny/crossref_metadata_2025_split huggingface dataset:
First Report of Potato Tuber Necrotic Ringspot Disease Caused by PVYNTN in Portugal
Authors: Serra M. C. , Weidemann H. L. 
Published: May 2007

During the last 2 years, potato (Solanum tuberosum L.) tubers displaying superficial necrotic arcs and rings were found in central Portugal. These symptoms increased during storage, and diminished tuber quality of ware (fresh-market) potatoes; however, no internal necrosis, which is typical for infections caused by tobacco rattle virus or potato mop top virus, was observed. The symptoms led to the preliminary diagnosis of potato tuber ringspot disease (PTNRD), caused by a tuber necrosis (TN)-inducing isolate of the tobacco veinal necrosis strain group of potato virus Y (PVYN) that was named PVYNTN. The occurrence of PVYNTN has been reported by a number of European countries. Suspect PTNRD tubers of the cv. Monalisa were obtained from several Portuguese potato growers and were tested with polyclonal antibodies (pabs) that reacted generally with PVY, and with monoclonal antibodies (mabs) raised against PVYN. Serogical tests were carried out in a double antibody sandwich (DAS) enzyme-linked immunosorbent assay (ELISA) with pabs and in a triple antibody sandwich (TAS) ELISA when mabs were used. As a result, the tubers were found to be infected with a virus isolate belonging to the PVYN strain group. Since PVYNTN cannot be distinguished serologically from other members of the PVYN strain group due to the similarities of their coat proteins (1), reverse transcription-polymerase chain reaction combined with immunocapture was applied for diagnostic purposes. The olignucleotide primers used were located in the 5′ non-coding region at nucleotide 103 and in the adjacent P1 protein gene coding region at position 919. This primer pair can be used to distinguish PVYNTN from other members of the PVYN strain group (2). Tests were carried out with plant sap from tubers and from plants grown from eye-cuttings and also from tobacco plants that were inoculated with plant sap of these potato tubers and plants. Control samples included sap from un-infected tobacco plants and from tobacco plants infected with a PVYN isolate and with the PVYNTN type strain “Hungary”. The expected amplification product of 835 bp appeared in the agarose gel with samples originally obtained from the tubers and with the PVYNTN control but not with the PVYNTN control, indicating that the tuber symptoms in potato cv. Monalisa were caused by infections with PVYNTN. This is the first report of the occurrence of PVYNTN in Portugal. References: (1) T. Dalmay and E. Balazs. Nucleic Acids Res. 18: 6721, 1990. (2) H. L. Weidemann and E. Maiss. Z. Pflanzenkr. Pflanzenschutz 103:337, 1996.
First Report of Bean Common Mosaic Necrosis Potyvirus (BCMNV) Infecting Common Bean in California
Authors: Guzman P. , Rojas M. R. , Davis R. M. , Kimble K. , Stewart R. , Sundstrom F. J. , Gilbertson R. L. 
Published: May 2007

During the 1996 growing season (June to September) an outbreak of bean common mosaic was detected in a navy bean field (cv. Snow Bunting) in Colusa County, CA. Early field inspections (August 1996) revealed an incidence of 5 to 10% infection, whereas a late field inspection (September) showed an incidence of 70 to 90% infection. Enzyme-linked immunosorbent assay (ELISA) was performed on 18 leaf samples from symptomatic plants collected from this field with two monoclonal antibodies (Mab): Mab I-2, which detects bean common mosaic necrosis virus (BCMNV) strains (previously necrotic or serotype A bean common mosaic potyvirus [BCMV] strains), and Mab 197, which detects BCMV strains (previously non-necrotic or serotype B BCMV strains) and BCMNV (3). ELISA results indicated BCMNV infection in all 18 samples. In order to confirm ELISA results and to further characterize the viral isolate(s), primary leaves of the differential bean cvs. Black Turtle Soup (BTS) T-39, Topcrop, Amanda, and Sutter Pink were inoculated mechanically with sap prepared from the same leaves used for ELISA. Within 1 week, BTS T-39 and Topcrop plants showed necrotic spots on inoculated leaves and systemic necrosis and death (black root rot symptoms), Sutter Pink showed typical systemic mosaic symptoms, and Amanda showed necrotic spots and restricted vein necrosis on inoculated leaves. These reactions were consistent with infection by the NL-3 strain of BCMNV (1). Reverse transcriptase-polymerase chain reaction was used to amplify a portion of the genome of the virus that contains the 3′ end of the coat protein (CP) gene and the 3′ untranslated region (UTR). A DNA fragment of approximately 670 bp was amplified and DNA sequence analysis revealed that the nucleotide sequences of the 3′ end of the CP and the UTR region of the California BCMNV isolate were 98 and 94% similar to those of the Michigan isolate of the BCMNV NL-3 strain (2), respectively. Together, these results suggest that the outbreak of bean common mosaic in the cv. Snow Bunting navy beans was caused by a pathogroup VI BCMNV isolate, and DNA sequence information suggests that it is similar to the NL-3 strain of BCMNV. This is the first report of BCMNV in California. References: (1) E. Drijfhout et al. Neth. J. Plant Pathol. 84:13, 1978. (2) G. F. Fang et al. Virus Res. 39:13, 1995. (3) G. I. Mink et al. Arch. Virol. S:397, 1992.
First Report from Morocco of Phytophthora infestans Isolates with Metalaxyl Resistance
Authors: Sedegui M. , Carroll R. B. , Morehart A. L. , Arifi A. , Lakhdar R. 
Published: May 2007

Late blight of potato (Solanum tuberosum L.) caused by Phytophthora infestans (Mont.) de Bary first appeared in Africa in 1941. It has been observed sporadically in Morocco for decades but only recently became a major problem. Significant losses have been recorded in the last two growing seasons in spite of the use of various disease control programs that included combinations of systemic and protectant fungicides. Phytophthora infestans was cultured from diseased foliage collected from commercial potato fields near Larache, Morocco. Isolates were analyzed to determine pathogenicity on several potato and tomato cultivars, mating type, genotype at two allozyme loci (2), and relative sensitivity to metalaxyl. Responses of the isolates to metalaxyl were assayed by mycelial radial growth on metalaxyl-amended agar, by floating leaves inoculated with P. infestans on metalaxyl solutions, and via potato tuber disks placed on filter paper saturated with metalaxyl solutions (1). Koch's postulates were completed; all isolates were pathogenic to potato and tomato cultivars tested, are consistent with the A1 mating type, and have the same allozyme pattern (Gpi 100/100, Pep 92/100) as US-6 genotype. All tests indicated resistance to metalaxyl up to 250 ppm. References: (1) K. L. Deahl et al. Am. Potato J. 70:779, 1993. (2) S. B. Goodwin et al. Plant Dis. 79:1181, 1995.
First Report of Rhizoctonia solani AG-7 in Georgia
Authors: Baird R. E. , Carling D. E. 
Published: May 2007

During a study to determine the pathogenic fungi overwintering on dead cotton (Gossypium hirsutum L.) roots, two isolates of Rhizoctonia solani Kühn anastomosis group 7 (AG-7) were identified. Isolate #213 was obtained from dead roots near Tifton, GA, and isolate #219 was cultured from cotton roots near Midville, GA. Rhizoctonia solani AG-7 was previously reported in Arkansas, Indiana, and Asia (1). Isolates #213 and #219 were tested in the greenhouse for pathogenicity by mixing 25 ml of 2-week-old cornmeal sand inoculum (3 g of cornmeal, 100 g of sand, and 20 ml of distilled water) into 20 × 100 cm pots containing 2.25 liters of sterile soil (Tifton loamy sand, pH 6.1) per pot. Pots with noninfested soil were included as a control. Eight seeds of cotton (Delta and Pineland 90 DPL 90) were sown per pot. Each pot was a replicate and each treatment was replicated five times. At 20 days after planting, plant stands in soil infested with isolate #213 or #219 averaged 2 to 3 or 4 to 5 plants per pot, respectively, while stands in noninfested soil averaged 7 to 8 plants per pot. Brownish colored, sunken lesions were observed on roots, hypocotyles, and cotyledons of plants from pots infested with R. solani AG-7. Isolates #213 and #219 were reisolated from plants grown in their respective treatments. This is the first report of R. solani AG-7 in Georgia. Reference: (1) R. E. Baird et al. Plant Dis. 80:1421, 1996.
Molecular Evidence for the Presence of Maize Bushy Stunt Phytoplasma in Corn in Brazil
Authors: Bedendo I. P. , Davis R. E. , Dally E. L. 
Published: May 2007

Previously, electron microscopy revealed that the corn (Zea mays L.) disease characterized by stunting and leaf reddening and commonly known as “red stunt” in Brazil is associated with plant infection by an unidentified phytoplasma (formerly mycoplasmalike organism) (1). During recent years, corn production in Brazil has been seriously affected by the increasing prevalence of a disease exhibiting symptoms similar to those of “red stunt.” The present investigation was initiated to determine the possible association of a phytoplasma with the current disease problem and to attain definitive molecular identification of any associated phytoplasma. To detect the possible presence of a phytoplasma in diseased corn in Brazil, plants exhibiting symptoms of stunting and leaf reddening in the field in 1995 and 1996 were assayed for the presence of phytoplasma DNA sequences by the use of polymerase chain reactions (PCR). We used primer pairs R16mF2/R16mR1 and R16F2n/R16R2 in nested PCRs (2) to prime phytoplasma-universal amplification of 16S ribosomal (r) DNA. Oligonucleotide pair rpF1/rpR1 (3) was used to prime phytoplasma-universal amplification of ribosomal protein (rp) gene operon sequences. Phytoplasma identification was accomplished by restriction fragment length polymorphism (RFLP) analysis of amplified 16S rDNA and rp gene operon sequences. Primer pair MBS-F1/MBS-R1 (4) was used to prime amplification of a maize bushy stunt (MBS)-specific chromosomal DNA sequence. Preparation of template DNAs, PCR conditions, and RFLP analyses of PCR products were as previously described (2–4). DNA amplification was observed in all PCRs containing template DNAs derived from symptomatic plants, indicating phytoplasmal infection of corn in Brazil. No DNA amplification was observed in PCR containing template DNA from healthy control corn plants. Polymorphisms in amplified 16S rDNA were those characteristic of phytoplasmas classified in 16S rRNA gene group 16SrI, subgroup I-B, of which MBS phytoplasma is a member (3). Collective RFLP patterns of amplified rp gene operon sequences were similar or identical to those observed in parallel tests for a known reference strain of MBS phytoplasma, indicating that the Brazilian corn plants were infected by MBS phytoplasma. Amplification of MBS-characteristic DNA was observed in PCRs containing MBS-specific primer pair MBS-F1/MBS-R1 and DNA from diseased corn, confirming infection of the plants by MBS phytoplasma. This work provides the first firm evidence for association of maize bushy stunt phytoplasma with the current disease problem of corn in Brazil. References: (1) A. S. Costa et al. Rev. Soc. Bras. Fitopatol. Piracicaba 4:39, 1971. (2) D. E. Gundersen and I.-M. Lee. Phytopathol. Mediterr. 35: 144,1996. (3) D. E. Gundersen et al. Int. J. Syst. Bacteriol. 46:64, 1996. (4) N. A. Harrison et al. Plant Dis. 80:263, 1996.
First Report of Anthracnose on Weeping Willow in Greece
Authors: Tzavella-Klonari K. , Aggelaki M. D. , Karadimos D. A. 
Published: May 2007

A serious disease of weeping willow (Salix babylonica) trees in home and public gardens was observed in the Chalkidiki region (northern Greece) during the spring of 1995 and 1996. Purplish-brown or black, small necrotic spots appeared on the leaves and often on leaf veins. Leaves became distorted and fell. Small, light, sunken cankers with dark brown rim and paler center, elongated in shape, appeared on the young shoots and on the leaf petioles. Severely affected shoots lost their weeping habit on which the tree's ornamental value is based. Whitish acervuli covered the leaf spots and the cankers. Masses of conidia emerged from the acervuli under high relative humidity conditions. The conidia were hyaline, clavate to pyriform, two-celled (unequally), measuring 14 to 19 × 4 to 7 μm, and belonged to the fungus Marssonina salicicola (Bres.) Magnus (1), which is the anamorph of the ascomycete Drepanopeziza sphaeroides (Pers.) Hohnel, the cause of anthracnose of weeping willow. The outbreak of the disease can be attributed to the rainy weather (70.5 and 105.5 mm of rain occurred in spring 1995 and spring 1996, respectively) and temperatures of 20°C. The disease is known to cause serious damage in some European countries, Canada, Egypt, Argentina, and New Zealand. This is the first report of the disease in Greece. Reference: (1) I. Vegh and J. Velastegui. Cryptogam. Mycol. 4:345, 1983.
Natural Infection of Eggplant by Puccinia substriata var. indica in the United States
Authors: Wilson J. P. , Williamson W. 
Published: May 2007

Eggplant (Solanum melongena) and other Solanum spp. are aecial hosts for Puccinia substriata var. indica, the rust pathogen of pearl millet (Pennisetum glaucum) (2). Although long suspected to be important in epidemic initiation (1), natural infection of eggplant has never been documented in the United States. All previous observations have been the result of deliberate inoculations. Eggplant (cv. Santana) seedlings with sporulating aecia were identified in the inventory of a vegetable transplant producer near Ty Ty, GA, on 22 April 1997. Flats of seedlings were being grown in a greenhouse with adjustable sides for creating an open-air environment for temperature control. Disease incidence was approximately 1.5% in the lot of 10,000 seedlings. Lesions were found most frequently on the first true leaf or less frequently on cotyledons. Aeciospores from 15 arbitrarily selected leaves were used to inoculate pearl millet seedlings in the greenhouse. Each leaf was used to inoculate pearl millet cultivars with no known resistance, and with the Rr1 resistance gene. Infection was obtained on all cultivars with no resistance genes, verifying pathogen identification. Fourteen isolates infected pearl millet with Rr1, revealing that virulence to Rr1 was common in this sample. The nearest point source of exposed pearl millet debris that could serve as a source of basidiospores was located approximately 9.7 km away from the eggplant. References: (1) H. D. Wells. Plant Dis. Rep. 62:469, 1978. (2) J. P. Wilson et al. Plant Dis. 80:806, 1996.
First Report of a Leaf Blight, Seed Stalk Rot, and Bulb Decay of Onion by Pantoea ananas in Georgia
Authors: Gitaitis R. D. , Gay J. D. 
Published: May 2007

In May 1997, sweet onions (Allium cepa L.) grown in Toombs County, GA, displayed symptoms of blighted leaves, bleached and rotted seed stalks, and rotted bulbs. Gram-negative bacteria were isolated from infected tissues on nutrient agar and shown to be from the genus Pantoea on the basis of cell morphology (rod-shaped), yellow pigmentation, utilization of glucose in an oxidative and fermentative manner, presence of catalase, and absence of oxidase. These characteristics are typical of bacterial strains belonging to the Enterobacteriaceae (facultative anaerobes). Initially, these bacteria were thought to be P. agglomerans, a common saprophyte associated with plant material. However, fatty acid analysis, using bacterial identification software (MIDI, Dewark, DE), identified (second choice) some strains as possibly being P. ananas.. Further testing indicated that all strains utilized cellobiose, melibiose, inositol, glycerol, and sucrose, but not pectin, starch, or gelatin. However, those strains identified by fatty acid analysis as P. ananas were differentiated from P. agglomerans on the basis of indole production, lack of phenylalanine deaminase, and lack of nitrate reductase. To confirm pathogenicity, three strains of each species (total of six strains) were grown overnight in nutrient broth shake cultures. Bacterial cells were harvested by centrifugation and suspended in 0.01 M phosphate-buffered saline (0.85%). Inoculum was adjusted to approximately 5 × 108 CFU/ml with a spectrophotometer and misted with a chromatography sprayer onto onion leaves of approximately 10-week-old onion plants in the greenhouse. Onions were predisposed by placing them under plastic bags for 18 h prior to inoculation. Inoculated plants were left covered with plastic bags for an additional 24 h after inoculation. There were two plants per pot, each test had three pots, and the test was conducted twice. The three strains of P. agglomerans and buffer control resulted in no symptoms. The three strains of P. ananas produced severe blighting, rapid collapse of tissues, and rapid drying so that leaves were light tan and dry within 3 days. Disease on plants infected with P. ananas continued to develop until death of all foliage and bulbs shriveled and collapsed. Results were consistent for all replications and both trials. Bacteria recovered from diseased tissues were gram-negative, yellow, and facultative anaerobic, and produced indole but not phenylalanine deaminase or nitrate reductase; i.e., the bacteria demonstrated the same characteristics as P. ananas. Although P. agglomerans has been reported to produce similar symptoms in South Africa (1), our P. agglomerans strains were nonpathogenic. To our knowledge this is the first report of P. ananas causing a disease of onion. Reference: (1) M. J. Hattingh and D. F. Walters Plant Dis. 65:615, 1981.
Iris Yellow Spot Tospovirus Detected in Onion (Allium cepa) in Israel
Authors: Gera A. , Cohen J. , Salomon R. , Raccah B. 
Published: May 2007

During March 1997, 20 to 30% of field-grown onion (Allium cepa), observed in Bet Shean Valley, Israel, had unusual viral symptoms of straw-colored ringspots on leaves and flower stalks. Leaf samples were analyzed by transmission electron microscopy (EM) of leaf dip preparations. Typical tospovirus-like particles were observed only with samples taken from symptomatic plants. Crude sap from symptomatic tissue was mechanically transmitted to Nicotiana benthamiana, Chenopodium quinoa, and Gomphrena globosa. On inoculated plants of N. benthamiana, chlorotic spots developed on inoculated leaves, followed by systemic necrosis, 4 and 7 days post inoculation (DPI), respectively. On inoculated plants of C. quinoa and G. globosa, necrotic local lesions developed by 4 to 5 DPI. EM studies with ultrathin sections of infected onion and N. benthamiana leaves revealed the presence of tospovirus-like particles. Virus was purified from mechanically infected N. benthamiana and identified as Iris yellow spot tospovirus (IYSV) by Western blots (immunoblots) and enzyme-linked immunosorbent assay (ELISA) (anti-IYSV antiserum was provided by D. Peters, Wageningen, the Netherlands). A high incidence of the disease observed in the surrounding fields and in other onion-growing areas in Israel was associated with large populations of the onion thrips (Thrips tabaci). Although characteristic symptoms have been noted on a frequent basis, effects on yield have yet to be determined. IYSV is known to occur in the Netherlands, where it has been occasionally detected in Iris (1) and leek (A. Porrum) (J. Verhoeven, personal communication). The detection of IYSV in Israel and the wide distribution of thrips in the natural vegetation may be an important constraint on onion and other bulb-crop production in Israel. Reference: (1) A. F. L. M. Derks and M. E. C. Lemmers. Acta Hortic. 432:132, 1996.
First Report of Butternut Canker Caused by Sirococcus clavigignenti-juglandacearum in New Brunswick, Canada
Authors: Harrison K. J. , Hurley J. E. , Ostry M. E. 
Published: May 2007

In June 1997, butternut canker was found for the first time in New Brunswick, Canada, at Stickney, Carleton County. A fungal isolate recovered from a young branch canker on butternut (Juglans cinerea L.), cultured on potato dextrose agar, produced spores and cultural morphology as previously described (1). This strain was retained as FSC-758 in the Fredericton Stock Culture Collection at the Atlantic Forestry Centre. The disease was also detected at four other locations in Carleton County along the Saint John River watershed within 20 km of the State of Maine. One stem canker examined at Peel, Carleton County, suggests the disease has been present at this site in New Brunswick for at least 7 years. The butternut tree is at the northeastern edge of its natural range in New Brunswick and, prior to the pathogen's detection, was believed to be far enough from infected butternut in the northeastern United States, Ontario, and Quebec to escape infection. Because planted specimens of butternut exist outside the tree's natural range in New Brunswick and in the neighboring provinces of Nova Scotia and Prince Edward Island, efforts are underway to determine how far the fungus has spread in the Maritime Provinces. Reference: (1) V. M. G. Nair et al. Mycologia 71:641, 1979.
First Report of Macrophomina phaseolina Causing Pre-harvest Cassava Root Rot in Benin and Nigeria
Authors: Msikita W. , James B. , Wilkinson H. T. , Juba J. H. 
Published: May 2007

In diagnostic surveys conducted in parts of Benin and Nigeria to determine the incidence of pre-harvest cassava root and stem rot during the dry season, Macrophomina phaseolina (Tassi) Goidanich constituted 14.2 and 18.7% of the total fungi (n = 201) associated with cassava root and stem rot from Benin and Nigeria (1). Pathogenicity of M. phaseolina on cassava was tested with cv. Agric. Inocula for pathogenicity tests were prepared by incubating 5-mm-diameter mycelial plugs for each of five isolates (Mp 1 to Mp 5, all collected from Benin) with 500 ml of autoclaved, sterilized, dehusked rice seed for 14 days at 30°C. Five 30-cm-long stem portions per isolate were cut from healthy cassava, surface disinfested in hot water (52°C, 5 min), and planted into 1-liter pots containing autoclaved, sterilized sand mixed with 10 ml of air-dried inoculum. Five plants per isolate similarly treated but not inoculated served as controls. Plants were watered once a week, and maintained in a greenhouse under natural light at 28 to 30°C. Lower leaves of inoculated plants gradually wilted, usually preceded by chlorosis, and brown to black lesions formed on the lower stem portions of some roots. Control plants remained asymptomatic. Plant height and percentage of leaf wilt (determined by counting the number of leaves wilted per plant and dividing by the total number of leaves per plant) were measured on a weekly basis for 8 weeks for each of the control and inoculated plants. At the end of 8 weeks, lesion length on the lower stem was measured. There were significant differences (P < 0.05) in length of the lesions and percentage of leaf wilt induced by the different isolates of M. phaseolina. Isolate Mp 1 induced the longest lesion (7.2 cm), followed by Mp 4 (4.1 cm), Mp 3 and Mp 5 (3.8 cm each), and Mp 2 (1.2 cm). Mp 4 induced the highest percentage of wilted leaves (53%), followed by Mp 1, Mp 3, and Mp 5 (30%), and Mp 2 (10%). All five M. phaseolina isolates (except Mp 3) reduced plant height, compared with control treatments. M. phaseolina was isolated from all infected plants, and the identification was independently confirmed by the International Mycological Institute, Surrey, UK. This is the first report of M. phaseolina causing pre-harvest cassava root rot in Benin and Nigeria. Reference: (1) W. Msikita et. al. Plant Dis. 81:1332, 1997.