bluuebunny/crossref_metadata_2025_split huggingface dataset:
First Report of Typhula Blight on Agrostis stolonifera and Poa annua in Italy
Authors: Titone P. , Mocioni M. , Garibaldi A. , Gullino M. L. 
Published: May 2007

During January 2002, Agrostis stolonifera and Poa annua turfgrasses on a golf course in Avigliana (northern Italy) exhibited 10- to 45-cm-diameter circular patches when the snow melted from the greens, tees, and fairways. Many patches coalesced to form large areas of strawcolored blighted turfgrass. At the patch margin, infected plants were covered with white-to-gray mycelium. Plants within patches were matted and appeared slimy with mycelium and sclerotia that were light pink, irregularly shaped, and less than 5 mm in diameter. Isolation from infected leaves on potato dextrose agar, supplemented with 100 mg/l of streptomycin sulfate, consistently yielded a fungus with mycelial, sclerotia, and cultural characteristics of Typhula incarnata (1). Pathogenicity tests were performed by spraying a suspension of mycelium and sclerotia, prepared by chopping mycelium and sclerotia produced in potato dextrose broth, onto 8-week-old A. stolonifera plants grown in plastic trays (45 × 30 cm). Trays were maintained at 0°C for 8 weeks in the dark. Blight symptoms developed on inoculated plants after 6 weeks. Non-inoculated plants remained healthy. The pathogen was reisolated from inoculated plants, and the pathogenicity test was repeated once. Typhula blight incited by T. incarnata was reported in Scandinavian countries and in several European countries including Holland, Germany, Austria, and Switzerland (1). To our knowledge, this is the first report of Typhula blight on turfgrass in Italy. Reference: (1) J. D. Smith et al. 1989. Fungal Diseases of Amenity Turf Grasses. E & FN Spong Ltd, London.
Root Rot and Stunting of Hydroponically Grown Endive, Fennel, and Sorrel Caused by Pythium F-group in South Africa
Authors: Labuschagne N. , Gull C. , Wehner F. C. , Botha W. J. 
Published: May 2007

Specialized vegetable crops such as endive (Cichorium endiva), fennel (Foeniculum vulgare), and sorrel (Rumex spp.) are being cultivated hydroponically in South Africa to be marketed as admixtures in salads. Stunted growth accompanied by browning and rotting of the root tips has been observed at a commercial recirculating gravel bed hydroponic system near Pretoria during the warm summer months. Root segments excised from symptomatic plants were rinsed in sterile water and plated on Pythium selective medium (1). Pythium F-group, characterized by the production of noninflated filamentous sporangia and no oospores (2), was isolated from 40% of endive, 60% of fennel, and 7% of sorrel root segments. Koch's postulates were confirmed by inoculating 4-week-old seedlings of each crop in the greenhouse with a Pythium F-group isolate from the particular crop. Inoculations were performed by adding 3 ml of suspension (105 zoospores per ml) to each liter of aerated nutrient solution. Control plants received no inoculum, and the experiment was repeated once. After 4 weeks, inoculated plants showed stunting of the foliage and slight to moderate root rot. Pythium F-group could readily be reisolated from roots of inoculated plants. To our knowledge, this is the first report of Pythium F-group on these crops in South Africa. References: (1) W. J. Botha and R. L. J. Coetzer. S. Afr. J. Bot. 62:196, 1996. (2) M. W. Dick. Keys to Pythium. University of Reading Press, Reading, UK, 1990.
Occurrence of Barley mild mosaic virus on Barley in Spain
Authors: Achon M. A. , Ratti C. , Rubies-Autonell C. 
Published: May 2007

Mosaic and yellowing symptoms were observed on winter barley during March of 2002 in northeastern Spain. Symptoms were similar to those caused by Barley yellow mosaic virus (BaYMV) and Barley mild mosaic virus (BaMMV), members of the genus Bymovirus (family Potyviridae). Leaves from 17 samples of barley were analyzed by enzyme-linked immunosorbent assay (ELISA) using antisera specific for BaYMV (Bio-Rad Laboratories, Hercules, CA) and BaMMV (Loewe Biochemica, Munich). Five samples tested positive with the BaYMV antiserum, and two samples were positive with the BaYMV and BaMMV antisera. Ranges of ELISA values were from 3.8 to 13 times higher than the negative controls with the BaYMV antiserum and from 18 to 21 times higher with the BaMMV antiserum. Mixed infections were further analyzed by reverse transcription-polymerase chain reaction (RT-PCR) using specific primers that amplify 433 bp of BaYMV (1) and 445 bp of BaMMV coat protein gene (primer 1: 5′GCG TCC GTT GCA ACT GA 3′ and primer 2: 5′GAA TTG CTT GTG CCA ACA 3′. A PCR product of the expected size was observed with BaMMV primers but not with BaYMV primers. The sequence of BaMMV PCR product was determined and compared with that of the equivalent regions of other BaMMV isolates (Genbank Accession Nos. AJ242725, AJ224872, D83410, D83408, L49381, Y10973, and Y10974). The greatest nucleotide identity (96 to 98%) was found with isolates from Germany and Italy, followed by those from France and the United Kingdom (89%), and the lowest identity being with isolates from Asia (85 to 88%). The BaYMV presence needs to be confirmed. To our knowledge, this is the first report of a bymovirus infecting barley in Spain, and illustrates the continuing spread within Europe of viruses vectored by Polymyxa graminis Led. Reference: (1) D. Hariri et al. Eur. J. Plant Pathol. 106:365, 2000.
Pumpkin (Cucurbita maxima and C. pepo), a new host of Beet pseudo yellows virus in California
Authors: Wintermantel W. M. 
Published: May 2007

In the summer of 2002, pumpkin plants (Cucurbita pepo L. and C. maxima Duchesne) with extensive leaf chlorosis similar to those observed in crinivirus infections were found in fields at two locations in Monterey County, California. Leaves of diseased plants were observed to have large populations of the greenhouse whitefly (Trialeurodes vaporariorum) present. Double-stranded RNA was extracted from symptomatic leaves of these plants and tested by northern hybridization for numerous criniviruses. A positive signal was identified exclusively with probes against the HSP70h gene of Beet pseudo yellows virus (BPYV) and confirmed by reverse transcription-polymerase chain reaction (RT-PCR) amplification of a 335-nucleotide section of the BPYV minor coat protein (CPm) gene (3). Similar symptoms were observed in additional fields in 2003, and BPYV was again confirmed. In addition, the CPm RT-PCR product was cloned into a TOPO pCR2 vector (Invitrogen, Carlsbad, CA) and sequenced. BLAST analysis of the cloned CPm RT-PCR product sequence corresponded to the published sequence of the CPm gene of BPYV (98%) (3) and Cucumber yellows virus (CuYV), a recently sequenced crinivirus considered to be a strain of BPYV (97%) (2). Incidence of BPYV in pumpkin appears to be variable and probably corresponds to the incidence of viruliferous whiteflies. On the basis of foliar symptoms, BPYV incidence varied from less than 50% in these fields in 2002 to nearly 100% infection of a large commercial field in 2003. BPYV is transmitted semipersistently by the greenhouse whitefly and has an extensive host range (1). The virus causes economic losses worldwide for greenhouse vegetable production and is becoming an increasing problem for field crops in areas of high greenhouse whitefly incidence (3). The impact of BPYV on pumpkin production remains to be determined; however, grower data suggests an increased incidence of fruit abortion and a substantial decrease in fruit weight. To our knowledge, this is the first report of BPYV infecting pumpkin. References: (1) J. E. Duffus. Phytopathology 55:450, 1965. (2) S. Hartono et al. J. Gen. Virol. 84:1007, 2003. (3) I. E. Tzanetakis et al. Plant Dis. 87:1398, 2003.
Anastomosis Grouping of Rhizoctonia solani Associated with Black Scurf and Stem Canker of Potato in South Africa
Authors: Truter M. , Wehner F. C. 
Published: May 2007

Rhizoctonia disease (black scurf of tubers and stem canker) of potato (Solanum tuberosum L.) caused by Rhizoctonia solani Kühn was first recorded in South Africa in 1918 (3). Although the sclerotial form on tubers is one of the most common potato diseases in the country, it is not known which anastomosis groups (AGs) of R. solani are involved. Between 1999 and 2001, R. solani was isolated from 28 plant and 56 soil samples collected in 7 (Eastern Free State, Gauteng, KwaZulu-Natal, Limpopo, Mpumalanga, Northern Cape, and Sandveld) of the 14 potato-production regions of South Africa and screened for hyphal anastomosis with tester strains of R. solani AG-1 to AG-10 according to Carling et al. (1). Of the 411 isolates from tubers with black scurf symptoms, 408 were AG-3 and three were AG-5. Symptomless tubers yielded two AG-3 isolates and three AG-5 isolates. Of 39 isolates from symptomatic stems and roots, 32 were AG-3, five were AG-4, and two were AG-5. Of the 127 isolates obtained from soil, 86, 28, 7, 3, and 3 were AG-3, AG-4, AG-5, AG-7, and AG-8, respectively. More than one AG was isolated from five of the seven regions. Virulence of 40 isolates representative of the above AGs was determined in triplicate on sprouts growing from seed tubers of potato cultivar Up-to-Date in a sand/soil mixture as described by Carling and Leiner (2) but using cultures grown in cornmeal/sand instead of colonized agar disks as inoculum. Damage to sprouts (lesions, girdling, and death) was assessed after 28 days at 16 to 28°C according to the 0 to 4 rating scale (2). Chi-square analysis of the data indicated that AG-3 was the most virulent, with isolates from sclerotia on tubers and lesions on stems more aggressive than those from symptomless tubers or soil. AG-4 and AG-5 caused significantly less disease than AG-3, but none of the AG-7 and AG-8 isolates showed any virulence to potato sprouts. References: (1) D. E. Carling et al. Phytopathology 77:1609, 1987. (2) D. E. Carling and R. H. Leiner. Phytopathology 80:930, 1990. (3) E. M. Doidge. S. Afr. Fruit Growers 5:6, 1918.
First Report of Monosporascus cannonballus on Melon in Brazil
Authors: Sales R. , Bezerra do Nascimento I. J. , de Souza Freitas L. , Beltrán R. , Armengol J. , Vicent A. , García-Jiménez J. 
Published: May 2007

Approximately 15,000 ha of melon (Cucumis melo L.) are grown in the northeastern section of Brazil, mostly for export to Europe during the winter months. Surveys for melon vine decline diseases were carried out in farms in the municipalities of Mossoró (Rio Grande do Norte) and Quixeré (Ceará) during 2002 and 2003. Symptoms typical of vine decline were observed in several fields and included yellowing of crown leaves just prior to harvest and collapse of many of the vines. Affected plants exhibited necrotic root systems and lacked most of the secondary and tertiary feeder roots. Numerous perithecia were observed on roots which, when examined with a microscope, showed characteristic asci and ascospores of the fungus Monosporascus cannonballus Pollack & Uecker (2). Isolations were made from the crown region and primary and secondary roots of affected plants by excising 4- to 6-mm pieces that were surface sterilized for 30 to 60 s with 1.5% active chlorine solution. Seven tissue pieces from each plant part were placed on potato dextrose agar (PDA) containing 0.5 g liter-1 of streptomycin sulfate. Plates were examined daily for fungal growth for 7 days, and hyphal tips from all colonies were transferred to PDA for subsequent growth and sporulation. M. cannonballus was isolated from 50% of the root sections. All isolates produced only one ascospore per ascus. Pathogenicity of four isolates was confirmed in the greenhouse on the muskmelon cv. Temprano Rochet. Inoculum was produced in a sand-oat hulls (Avena sativa L.) medium (0.5 liter of sand, 46 g of ground oat hulls, and 37.5 ml of distilled water) and incubated at 25°C for 1 month. Colony forming units (CFU) were quantified by serial dilution using 1% hydroxyethyl cellulose. A sterilized mixture of equal portions (vol/vol) of sand and peat moss was used to fill plastic pots (17 cm in diameter), and inoculum was added to produce an inoculum concentration of 20 CFU g-1. Five melon seeds were planted in each pot and after germination, were thinned to one seedling per pot. There were five replicated pots for each treatment with an equal number of uninfested pots. Plants were evaluated for disease 45 days after sowing. Roots were exposed by carefully washing the potting mix away. All isolates of M. cannonballus tested were highly aggressive and caused severe root necrosis compared with the noninoculated control plants. M. cannonballus was reisolated from symptomatic plants, confirming Koch's postulates. Double cropping in the same fields for several years has created serious problems in Brazil, which are related to this soilborne pathogen that also causes root rot and vine decline of watermelon (Citrullus lanatus (Thunb.) Matsum. & Nakai) worldwide (1). To our knowledge this is the first report of M. cannonballus in Brazil and South America. References: (1) R. D. Martyn and M. E. Miller. Plant Dis. 80:716, 1996. (2) F. G. Pollack and F. A. Uecker. Mycologia 66:346, 1974.
Bacterial Spot of Tomato and Pepper Caused by Xanthomonas axonopodis pv. vesicatoria in the Western Mediterranean Region of Turkey
Authors: Basim H. , Basim E. , Jones J. B. , Minsavage G. V. , Dickstein E. R. 
Published: May 2007

Xanthomonas axonopodis pv. vesicatoria, causal agent of bacterial spot of tomato (Lycopersicon esculentum L.) and sweet pepper (Capsicum annuum L.) was isolated from tomato and pepper plants in greenhouse production in the Province of Antalya, in southwestern Turkey. Disease incidence was less than 4% of plants observed in 2001 and ranged from 1 to 20% in 2002. Eleven seedling-producing companies and 26 greenhouses that produce tomato and pepper were surveyed during the rainy seasons of 2001 and 2002. The increase in disease incidence in 2002 is an indication that this disease is becoming more prevalent on tomato and pepper plants grown in greenhouses in southwestern Turkey. A gram-negative bacterium producing yellow-pigmented colonies on nutrient agar was consistently isolated from brown, circular spots on leaflets of tomato and sweet pepper seedlings. Five isolates were pathogenic on commercial cultivars of tomato and pepper when bacterial suspensions (108 CFU/ml) were infiltrated into the intercellular spaces of leaves to determine race by using procedures described by Bouzar et al. (1). All the isolates produced hypersensitive reaction responses on tomato genotype cv. Hawaii 7998 and pepper genotype cvs. 20 R and 30 R and were designated tomato race 1 pepper race 1 (T1P1) (1). Fatty acid analysis of the strains identified them as X. axonopodis vesicatoria with similarity index values of 0.872 to 0.933. In addition, the strains were tested with X. axonopodis vesicatoria-specific polymerase chain reaction primers (RST 2/3 and RST 9/10) (2). The isolates were determined to be X. axonopodis vesicatoria. Although bacterial spot of tomato has been suspected in Turkey for a number of years, to our knowledge, this is the first report of the bacterium on tomato. References: (1) H. Bouzar et al. Phytopathology 84:663, 1994. (2) R. P. Leite, Jr. et al. Appl. Env. Microbiol. 60:1068, 1994.
Occurrence of Podosphaera xanthii Race 2 on Cucumis melo in Brazil
Authors: Kobori R. F. , Suzuki O. , Wierzbicki R. , Della Vecchia P. T. , Camargo L. E. A. 
Published: May 2007

Powdery mildew is an important disease of melons (Cucumis melo L.) cultivated in greenhouses in Brazil. Currently, there are 5 races of Podosphaera xanthii (formerly known as Sphaerotheca fuliginea) and 2 races of Golovinomyces cichoracearum (formerly known as Erysiphe cichoracearum) described on melons worldwide, but only race 1 of P. xanthii has been reported in Brazil (1). However, typical whitish powdery fungal growth was observed on an experimental hybrid yellow melon resistant to race 1 of P. xanthii during the summer of 2000 in a greenhouse in Bragança Paulista, State of São Paulo. Conidia collected from diseased leaves were spread onto 0.5% water agar medium and maintained at 22°C for 24 h with 12 h of light and 12 h of darkness. Most of the germinated conidia displayed fibrosin inclusion bodies when observed in a solution of 3% potassium hydroxide (KOH), and approximately 1 of 50 also displayed forked germ tubes. These features allowed us to identify P. xanthii as the causal agent. Conidia raised on the susceptible yellow melon ‘Amarelo CAC’ were used to inoculate cotyledons of the differential melon lines (2) ‘Hale's Best Jumbo’ (susceptible to races 1, 2, and 3 of P. xanthii), ‘PMR-45’ (resistant to race 1 and susceptible to races 2 and 3), and ‘PMR-6’ (resistant to races 1 and 2 and susceptible to race 3). Inoculations were performed on 10 plants of each differential line and replicated four times. The presence or absence of symptoms was evaluated 18 days after inoculation. ‘Hale's Best Jumbo’ and ‘PMR-45’ were rated as susceptible while ‘PMR-6’ was rated as resistant, thus indicating the presence of race 2 of P. xanthii in Brazil. During field surveys from 2001 to 2003, this race was found on squash (Cucurbita moschata), summer squash (C. pepo), and melons in São Paulo. References: (1) F. J. B. Reifschneider et al. Plant Dis. 69:1069, 1985. (2) C. E. Thomas et al. Cucurbit Genet. Coop. 7:126, 1984.
First Report of Spot Type of Barley Net Blotch Caused by Pyrenophora teres f. sp. maculata in Uruguay
Authors: Pereyra S. A. , Germán S. E. 
Published: May 2007

In September 2003, leaves exhibiting spot-type lesions similar to those produced by Cochliobolus sativus Drechs. ex Dastur were widely observed in six commercial barley crops of cvs. Norteña Daymán, Norteña Carumbé, and MUSA 936 in Soriano and Río Negro provinces, the main barley production region in western Uruguay. Spot lesions were tan to dark brown, circular to elliptical, and 3 to 10 mm in diameter. Larger lesions were surrounded by a chlorotic margin of varying width. Affected leaf pieces (10 to 15) from each field were placed in a moist chamber for 2 days to promote sporulation. A fungus identified morphologically as Pyrenophora teres (Died.) Drechs. (1) was consistently isolated from infected leaves. However, symptoms did not correspond to the net-type lesions of net blotch commonly produced by P. teres f. sp. teres in Uruguay. Three monoconidial cultures were obtained by transferring single conidia to potato dextrose agar and then to 10% V8 juice agar and incubated at 20 to 22°C with a 12-h photoperiod for 10 days. Adding sterile water to each plate and gently rubbing the surface with a microscope slide prepared inoculum for pathogenicity tests. Conidia concentration was adjusted to 1 × 104 conidia per ml. Sixty-eight barley genotypes from Uruguay, ICARDA/CIMMYT, and North Dakota were grown in the greenhouse for 2 weeks at 20 to 22°C with a 14-h photoperiod. For each monoconidial isolate, three seedlings of each genotype were inoculated at the three-leaf stage 15 to 16 days after seeding with 0.4 ml of the inoculum suspension with an airbrush inoculator. A drop of Tween 20 was added per 40 ml of inoculum suspension. One set of each genotype was inoculated with sterile water as a control. Seedlings were placed in a dew chamber at 20°C and 100% relative humidity in the dark for 24 h and then returned to prior conditions. The first lesions developed after 7 to 9 days. Leaves two and three of the plants were visually rated for disease (3) 13 days after inoculation. Control plants were disease free. The most susceptible reactions were observed on cvs. Norteña Daymán, MUSA 936, and line CLE 230 (Uruguay). Symptoms were similar in shape and size to those observed in the fields. The most resistant infection types were observed on several Uruguayan and North Dakota advanced lines. The fungus was consistently reisolated from inoculated plants. On the basis of morphology and symptoms produced, the pathogen was identified (2) as P. teres. f. sp. maculata Smedeg. To our knowledge, this is the first report of this fungus causing spot-like symptoms of net blotch in Uruguay. References: (1) M. B. Ellis. Dematiaceous hyphomycetes, CABI, Oxon, UK, 1971. (2) V. Smedergaard-Petersen. Pages 124–144 in: R. Vet. Agr. Univ. Yearbook, Copenhagen, 1971. (3) A. Tekauz. Can. J. Plant Pathol.7:181, 1985.
First Report of Powdery Mildew Caused by Erysiphe heraclei on Chervil in California
Authors: Koike S. T. , Saenz G. S. 
Published: May 2007

Chervil (Anthriscus cerefolium) is a culinary herb in the Apiaceae family that is grown commercially in California. In 2003 and 2004, shade house plantings of chervil in central coastal California exhibited symptoms and signs of a powdery mildew disease. White, epiphytic mycelia and conidia were present on petioles and leaves. Severely affected leaflets became slightly twisted and bent. Mycelium was amphigenous and effused or in patches. Hyphae measured 5.0 to 7.5 μm in diameter and had lobed appressoria. Conidiophores were straight and had cylindric foot cells measuring 25.0 to 37.5 × 7.5 to 10.0 μm, followed by a longer cell and one to two shorter cells. Conidia formed singly, were cylindric, and measured (37.5-) 40.0 to 50.0 (-52.5) × 15.0 to 17.5 μm. Conidia lacked fibrosin bodies and germinated at the ends with either a very short or a long germ tube forming a lobed appressorium (Polygoni type). No cleistothecia were observed. On the basis of these characteristics, the fungus was identified as Erysiphe heraclei (1). To confirm pathogenicity, severely colonized chervil leaves from a commercial nursery were gently pressed onto leaves of potted chervil plants. Plants were then maintained in a greenhouse (22 to 24°C). After 10 to 12 days, signs of powdery mildew developed on the foliage of inoculated plants, and the pathogen morphology matched that of the originally observed pathogen. Noninoculated control plants did not develop powdery mildew. To investigate the host range of this chervil isolate, parsley (Petroselinum crispum) and celery (Apium graveolens) plants were inoculated in the same way as described. However, after more than 3 weeks, no powdery mildew developed on these two Apiaceae plants. Control chervil plants again developed the disease. To our knowledge, this is the first report of powdery mildew of chervil caused by E. heraclei in California. Disease impact was severe, and in some cases, chervil crops were not harvested. The inability of the chervil isolate to infect two other Apiaceae plants that are listed as hosts of E. heraclei indicates that this pathogen may consist of strains having different host ranges. Reference: (1) U. Braun. Nova Hedwigia 89:1, 1987.