bluuebunny/crossref_metadata_2025_split huggingface dataset:
A New Root and Crown Rot Disease of Heath in California Caused by Cylindrocladium pauciramosum
Authors: Koike S. T. , Henderson D. M. , Crous P. W. , Schoch C. L. , Tjosvold S. A. 
Published: May 2007

Heath (Erica capensis Salter) is a woody, evergreen plant used in Cali-fornia as a landscape shrub or ground cover. In 1997, a new root and crown disease was found in commercial nursery plantings of potted heath. A similar disease was found in 1998 on heath transplants being grown as liners. In both situations, roots were necrotic and crown tissue turned brown. Affected plants became gray-green in color, withered, and died. A Cylindrocladium species was consistently isolated from roots, crowns, and lower stems of symptomatic plants. Isolates were characterized by having penicillate conidiophores terminating in obpyriform to broadly ellipsoidal vesicles. Conidia were hyaline, 1-septate, straight with rounded ends, (30-) 45 to 55 (-60) × (3.5-) 4 to 5 μm, placing it in the Cylindrocladium candelabrum Viégas species complex. Ten single-conidial isolates produced perithecia with viable progeny of Calonectria pauciramosa C.L. Schoch & Crous when mated on carnation leaf agar with tester strains of Cylindrocladium pauciramosum C.L. Schoch & Crous (1). Matings with tester strains of all other species in this complex proved unsuccessful. Pathogenicity of 8 representative isolates was confirmed by applying 3 ml of a conidial suspension (3.0 × 105 conidia per ml) to the crowns of potted, 6-month-old, rooted heath cuttings that were subsequently maintained in a greenhouse (23 to 25°C). After 2 weeks, plant crowns and roots developed symptoms similar to those observed in the field, and plants later wilted and died. C. pauciramosum was reiso-lated from all plants. Control plants, which were treated with water, did not develop any symptoms. The tests were repeated and the results were similar. This is the first report of C. pauciramosum as a pathogen of heath, and the first record of this pathogen from North America. Reference: (1) C. L. Schoch et al. Mycologia 91:286, 1999.
Isolation of Trichoderma harzianum Th2 from Commercial Mushroom Compost in Spain
Authors: Hermosa M. R. , Grondona I. , Monte E. 
Published: May 2007

Trichoderma spp. are associated with green mold of mushrooms. This fungal disease has caused severe losses in mushroom production in countries such as Ireland, the United Kingdom, Canada, and the United States. This disease is caused by two biotypes of T. harzianum (Th2, Europe; Th4, North America) (1,2). Both biotypes have not been detected in mushrooms or other material in Spain previously. However, during 1998, green mold was detected at facilities dedicated to produce compost, as well as in facilities used to produce Agaricus bisporus (Lange) Imbach. Three compost samples were isolated from commercial bags with mushroom substrate and three more samples were taken from mushroom yards. Several spores were isolated by the dilution plate method. Initial identification of the pathogenic fungi was made by examining cultures grown on potato dextrose agar. Morphological characteristics of all isolates coincided with the description of T. harzianum (3). The following amounts of CFU per g were found in commercial compost samples: 1.2 × 108, 5.5 × 107, and 1.4 × 107 per g; whereas 3 × 108, 12.4 × 107, and 2.2 × 106 were obtained from mushroom yards. The fragment containing the internal transcribed spacer (ITS1) was amplified and sequenced for each of the six samples obtained. The ITS1 sequence (201 bp) was identical in all samples, and the sequence was aligned, with Clustal W, with Th2 and Th4 biotype sequences of the EMBL data base. The ITS1 sequence showed 0.55% divergence from Th2 isolates and more distance, 3.3%, with Th4 isolates. The ITS1 sequence obtained with all Spanish samples studied, EMBL accession number AJ1321550, was identical to that described for the Irish isolate Th2I (#63), with accession number U78880 in the EMBL data base (1). This is the first description of the Th2 biotype in Spain. References: (1) M. D. Ospina-Giraldo et al. Mycologia 90:76, 1998. (2) D. L. Rinker et al. Mushroom World 8:71, 1997. (3) D. A. Seaby. Plant Pathol. 45:905, 1996.
First Report of Pestalotiopsis guepini on Loquat in Argentina
Authors: Perelló A. E. , Larran S. 
Published: May 2007

Loquat, Eriobotrya japonica (Thunb.) Lindl., is used as an ornamental plant in home gardens in the La Plata area of Buenos Aires, Argentina. During spring 1998, loquat branches with spotted leaves and fruits were submitted to the Plant Disease Diagnostic Laboratory. Symptoms on leaves consisted of small (2 to 5 mm in diameter), circular to oblong, greenish brown lesions that expanded to amphigenous, isolated, or confluent, dark brown spots. On fruits the disease appeared as circular to elongated, sunken spots. Advancing lesions spread over the surface resulting in the death of the fruit. Acervuli were observed within lesions. Isolations from symptomatic tissue onto acidified potato dextrose agar medium consistently yielded white fungal colonies of sparse aerial mycelium with acervuli containing black, slimy spore masses. The fungus was initially identified as Pestalotiopsis guepini (Desmaz.) Steyaert based on conidial and cultural characteristics (1), and the identification was confirmed by Institute Spegazzini, La Plata, Buenos Aires, Argen-tina. Loquat branches with fruit and 3- to 6-month-old loquat plants were mechanically injured and sprayed with a conidial suspension of one of the P. guepini isolates (4.5 × 105 per ml). Plants were incubated in a moist chamber for 48 h and then maintained in a greenhouse. After 6 days, lesions similar to the original symptoms were observed on the inoculated plant and P. guepini was reisolated, confirming Koch's postulates. Control plants sprayed with distilled water remained symptomless. This is the first report of P. guepini causing leaf and fruit spots on loquat in Argentina. Reference: (1) J. B. H. J. Desmazières. Ann. Sci. Nat. Ser. 2. 13:181, 1840.
First Report of Alternaria alternata Causing Leaf Spot on English Walnut
Authors: Belisario A. , Forti E. , Corazza L. , van Kesteren H. A. 
Published: May 2007

A foliar disease of English walnut (Juglans regia L.) was observed in 1998 in an orchard in northern Italy. Symptoms consisted of circular, necrotic spots bordered with concentric zones of darker tissue. Average lesion diameter was 20 mm, although lesions could extend to half of the leaflet lamina. A fungus identified as Alternaria alternata (Fr.:Fr.) Keissl. (1) was observed on the necrotic tissue and was consistently isolated from the margins of the necrosis. Conidia from leaves were brown, ellipsoid to ovoid (primary conidia 28 to 60 × 8 to 15 μm; secondary conidia 10 to 30 × 7 to 13 μm), with walls often ornamented, 1 to 6 transversely septate and 0 to 3 longitudinally septate. For pathogenicity tests, three isolates were grown on potato dextrose agar for 2 weeks. Inoculations were performed on detached, surface-sterilized, healthy J. regia leaflets. Four drops (5 μl each) of a sterile water suspension of 1 × 105 conidia per ml were placed on each leaflet; three leaves per isolate were used. Leaves were incubated in a moist chamber. After 10 days, leaf spots similar to the original symptoms developed on all the inoculated points for all three isolates, and the pathogen was reisolated. Control leaflets inoculated with sterile, distilled water remained symptomless. The experiment was performed three times and the results were similar. Alternaria alternata is a well-known pathogen on many crops but a few records report this fungus as a causal agent of leaf spot on deciduous trees. This is the first report of A. alternata on English walnut. Reference: (1) E. G. Simmons. Mycotaxon 37:79, 1990.
First Report of a Septoria sp. on Common Ragweed (Ambrosia artemisiifolia) in Europe
Authors: Bohár Gy. , Schwarczinger I. 
Published: May 2007

During a survey for potential biocontrol agents of common ragweed (Ambrosia artemisiifolia var. elatior (L.) Descourt) in 1997, plants exhibiting irregular, brown leaf spots were collected repeatedly from six roadside locations in Pest County, Hungary. Many pycnidia developed in the necrotic tissues on detached leaves after 2 days in moist chambers. Pycnidia were globose to slightly flattened, brown, thin walled, 58 to 100 μm in diameter, with a definite ostiole. Conidia were hyaline, filiform with 2 to 3 septa, and 22.0 to 38.0 × 0.7 to 1.3 μm in size. The fungus was isolated on potato dextrose agar and identified as a Septoria sp. To confirm pathogenicity, potted ragweed seedlings were sprayed with a suspension of 5 × 106 conidia per ml from pure cultures of the Septoria sp., placed in a dew chamber for 72 h, and then grown in a greenhouse at 16 to 24°C. After 2 weeks, inoculated plants developed small, brown lesions on leaves and leaf petioles. Three weeks after inoculation, necrotic lesions had enlarged to 1 to 3 mm in diameter with irregular, distinct margins and light brown centers. The lesions on the lower leaves were larger and more numerous than on leaves nearer the tops of the plants. Pycnidia developed on the senescent leaves after 1 month. Infected leaves became completely necrotic and occasionally entire plants died. The pathogen was reisolated from all inoculated plants, thus satisfying Koch's postulates. A voucher specimen was deposited at the Department of Botany of the Hungarian Natural History Museum in Buda-pest (No. BP 92081). Septoria ambrosiae Hemmi et Naito was described on ragweed in Japan (1), but our isolate is morphologically distinct from that species. This is the first report of a Septoria sp. on A. artemisiifolia in Europe. Reference: (1) N. Naito. Mem. Coll. Agric. Kyoto 47:41, 1940.
First Report of Onion Yellow Dwarf Virus in Ontario
Authors: Stobbs L. W. , Van Driel L. 
Published: May 2007

Onion yellow dwarf virus (OYDV) (1) was identified in a commercial planting of garlic (Allium sativum L.) near Delhi, Ontario, in 1998. Infected plants exhibited mild mosaic symptoms that became less noticeable by mid-July. Many plants were co-infected with garlic latent virus (GLV) (4), which was mechanically transmitted to leek (A. porrum L.). Since leek is not susceptible to OYDV (3), it is an appropriate host for the differentiation of GLV and OYDV. OYDV was transmitted nonpersistently by Myzus persicae (Schultz) from garlic to garlic and onion (A. cepa L.). Infected onion exhibited yellow striping, leaf curling, and pronounced stunting. Necrotic lesions were not present on inoculated leaves of Chenopodium amaranticolor Coste & Reyn. and C. quinoa Willd., which are often associated with co-infection with leek yellow dwarf virus (2). The isolate reacted strongly in enzyme-linked immunosorbent assay with OYDV antisera (from M. Fukami, Chiba Prefectural Agric. Exp. Stn., Chiba 266, Japan; D. Z. Maat, DLO Research Instit., Plant Prot., Wageningen, The Netherlands). Electron microscopic observations of negatively stained preparations of infected leaf tissues revealed virus particles averaging 765 ± 45 nm with typical pinwheel inclusions. References: (1) L. Bos. CMI/AAB Descrip. Plant Viruses no. 158, 1976. (2) K. Graichen. Nachrichtenbl. Pflanzenschutz DDR 32: 245, 1978. (3) K. Graichen and H. U. Leistner. Arch. Phytopathol. Pflanzenschutz 23:165, 1987. (4) L. W. Stobbs et al. Plant Dis. 80:343, 1996.
Infection of Potatoes by Oospores of Phytophthora infestans in Soil
Authors: Strömberg A. , Persson L. , Wikström M. 
Published: May 2007

Phytophthora infestans (Mont.) de Bary, causing late blight on potatoes and considered to be a typical airborne disease, was found to be infective also by oospores in the soil. P. infestans is heterothallic, and is known to reproduce asexually in Sweden since only one mating type, A1, was present until 1986. Since the 1970s, the other mating type, A2, of P. infestans has migrated to most parts of the world from its original location in central Mexico (2). When A1 and A2 meet, they may form oospores, which are thick-walled, resting structures, giving the pathogen a possibility to recombine as well as survive without its host, for instance in the soil. The soil stages of the pathogen are now therefore under intense investigation. Oospores of P. infestans were produced from two Scandinavian A1 and A2 isolates in Rye A broth mixed with talcum powder and dried for 7 weeks. The inoculum was mixed with sterile, standardized soil in concentrations of 10, 150, 250, and 400 oospores per ml of soil. Cv. Bintje plants cultivated in vitro from nodal cuttings on Murashige and Skoog medium were transplanted to the soil after rooting. Brown discolorations were obtained on the underground stems and tubers on potato plants grown in the two highest concentrations of oospores for 1 month at 15°C and 16-h day length. After 3 days of incubation on P. infestans-selective medium (3), sporangia covered the tissue from plants grown in 250 and 400 oospores per ml of soil and the pathogen was reisolated. This shows that germinating oospores of P. infestans can infect underground stems and tubers of potatoes in soil and further explains the early attack of late blight as observed in a potato crop in Sweden 1996 and 1997 (1). References: (1) B. Andersson et al. Potato Res. 41:305, 1998. (2) D. Andrivon. Phytopathology 85:1053, 1995. (3) G. W. Griffith et al. Mycologist 9:87, 1995.
An Immunity (QL3) Breaking Strain of Sorghum Mosaic Potyvirus in India
Authors: Mali V. R. 
Published: May 2007

Sorghum (Sorghum bicolor) line Tx2786 is immune to strains or isolates of sorghum mosaic potyvirus (SrMV strains SCH and SCH) but susceptible to strains of maize dwarf mosaic (MDMV) and sugarcane mosaic (SCMV) potyviruses (1,2). When grown in proximity to sugarcane, Tx2786 was infected with a virus that caused mosaic and necrotic symptoms during the postrainy season of 1994 (14 to 30°C) at Parbhani (Maharashtra, India). Leaf-dip electron microscopy performed on virus-infected sorghum and sugarcane tissues revealed particles, 720 × 12 nm, typical of a potyvirus. A potyvirus isolate (designated IBS) was readily transmitted mechanically from field-infected sorghum (Tx2786) and sugarcane (Saccharum officinarum cv. Co.740) to 18 glasshouse-grown sorghum inbred lines. All sorghum lines (QL-3 from India and Tx2786), including those resistant to SrMV, SCMV, MDMV, and johnsongrass mosaic potyvirus (JGMV), were infected. IBS caused necrosis in Cargill-40, Hegari, PI-35038, RTx09, Tx2786, QL-3 from India, and Redlan lines and mosaic symptoms in RTx430, SA-394, Atlas, Martin, BTx3048, Caprock, NM-31, QL-11, SCO-175-14E, Rio, and BTx623 lines. Sorghum reactions to sorghum and sugarcane virus isolates were similar. IBS also infected maize (Zea mays cv. African Tall), johnsongrass (S. halepense cv. 81, symptomless infection), and sorghum (S. bicolor cv. CS-3541) but not prosomillet (Panicum miliaceum), fingermillet (Eleusine coracana cv. IE-2540), pearl millet (Pennisetum typhoides cv. NHB-3), or oat (Avena sativa cv. Kent) when sap transmitted. IBS also was transmitted by the corn leaf aphid (Rhopalosiphum maidis) in a nonpersistent manner from sorghum and sugarcane to all 18 sorghum lines in a glasshouse. Based on direct antigen-coating enzyme-linked immunosorbent assay (DAC-ELISA), serologically specific electron microscopy, and Western blot tests, IBS was serologically related to SrMV strains SCH and SCI (2–4) but not to MDMV strains A, D, and E; SCMV strains A, B, D, SC, and MDB; or JGMV type strain from Australia and strain O from Texas (2). IBS induced formation of cytoplasmic cylindrical inclusions consisting of pinwheels associated with long, straight, laminated aggregates (subdivision type II) in sorghum and sugarcane host cells. Purified IBS contained one major polypeptide of 40 kDa and a ribonucleic acid of 3.0 × 106 Da. Polyclonal antiserum to IBS was produced in rabbits and used in DAC-ELISA to confirm the identity of IBS in sugarcane, sorghum lines, and other test plant species. On the basis of biological and serological properties, IBS isolated from field-infected sorghum grain Tx2786 and sugarcane cv. Co.740 is identified as an immunity (QL3) breaking strain of SrMV (SrMV-IBS). References: (1) L. M. Giorda et al. Plant Dis. 70:624, 1986. (2) D. D. Shukla et al. Phytopathology 79: 223, 1989. (3) D. D. Shukla et al. 1998. AAB Description of Plant Viruses No. 359. AAB, Kew, Surrey, England. (4) Z. N. Yang and T. E. Mirkov. Phytopathology 87:932, 1997.
First Report of Powdery Mildew Caused by an Oidium sp. on Torenia fournieri
Authors: Holcomb G. E. 
Published: May 2007

Torenia fournieri Lind. ex Fourn. (wishbone flower, bluewings) is a popular summer bedding plant in Louisiana. Clown Mixture cultivars are available in garden centers in March and April. Transplants of cultivar Clown Rose were purchased, transplanted to larger pots, and maintained in a greenhouse. A powdery mildew was observed on these plants in March and all plants (six) were severely diseased by May. Symptoms included leaf distortion and yellowing. Powdery mildew was not present on transplants and none was found in later checks of garden centers. An Oidium sp. was observed sporulating on both leaf surfaces of infected plants. Conidia were ellipsoid, produced in chains, lacked fibrosin bodies, and averaged 41 × 22 μm in dimensions. No sexual stage was observed. Healthy plants of Clown Mixture cultivars were obtained and inoculated by brushing conidia from infected plant leaves to leaves of healthy plants. Plants were maintained in a greenhouse where temperatures ranged from 16 to 26°C. Hyphal growth appeared on inoculated plants after 5 days and the reproductive structures formed later appeared the same as those on originally infected plants. Uninoculated plants remained healthy. No previous reports of powdery mildew diseases of T. fournieri in the United States were found. Other powdery mildew pathogens reported on T. fournieri are Sphaerotheca fuliginea (Schlechtend.:Fr.) Pollacci in Finland and Japan and an Erysiphe sp. in Japan (1). Reference: (1) K. Amano. Host Range and Geographical Distribution of the Powdery Mildew Fungi. Japan Scientific Press, Tokyo, 1986.
First Report of Golden Dwarf Mistletoe on Pinus maximinoi
Authors: Mathiasen R. , Sesnie S. , Calderon J. , Soto A. 
Published: May 2007

Golden dwarf mistletoe (Arceuthobium aureum subsp. aureum Hawksw. & Wiens) is endemic to east-central Guatemala (Departments Alta Verapaz, Baja Verapaz, and Quiche) (1,2). Its principal hosts are Pinus pseudostrobus Lindl., P. montezumae Lamb., and P. oaxacana Mirov (1). In May 1999, A. aureum subsp. aureum was observed infecting Pinus maximinoi H. E. Moore at four locations: 1.0 km south (altitude 1,580 m) and 5.4 km north (altitude >1,630 m) of La Cumbre, Baja Verapaz on Route CA-14, 8 km west (altitude 1,670 m) of Chilasco, Baja Verapaz, and 5 km west (altitude 1,490 m) of San Cristobal Verapaz, Alta Verapaz on Route 7-W. Although previous reports (1,2) indicated that golden dwarf mistletoe does not induce witches'-brooms on its hosts, older (>50 years), severely affected P. maximinoi were observed to have formed large witches'-brooms as a result of dwarf mistletoe infection. Although it has been suggested that Pinus oocarpa Schiede is susceptible to golden dwarf mistletoe (1), several large trees of this species were observed growing within 5 m of infected P. maximinoi at three of the four locations, but none were infected. This is the first report of golden dwarf mistletoe on P. maximinoi. References: (1) F. G. Hawksworth and D. Wiens. 1996. Dwarf Mistletoes: Biology, Pathology, and Systematics. USDA Agric. Handb. 709. (2) D. Wiens and C. G. Shaw, J. Idaho Acad. Sci. 30:25, 1994.
First Report of Pepino Mosaic Virus on Tomato
Authors: van der Vlugt R. A. A. , Stijger C. C. M. M. , Verhoeven J. Th. J. , Lesemann D.-E. 
Published: May 2007

Early in 1999 a new viral disease occurred in protected tomato (Lycopersicon esculentum) crops in the Netherlands. Infected plants showed yellow leaf spots and mosaic. Transmission electron microscopic analysis revealed particles typical of potexviruses. Only three potexviruses have been reported to infect solanaceous crops: Pepino mosaic virus (PepMV), Potato aucuba mosaic virus (PAMV), and Potato virus X (PVX). Inoculation of test plants and serological tests showed that the new virus clearly differed from PAMV and PVX. Immuno-electron microscopy with antiserum to PepMV (1), the original PepMV isolate, and the virus from tomato showed decoration titers of 1:800 (homologous) and 1:400, respectively. Neither virus reacted with antiserum to PVX, nor did PVX react with antiserum to PepMV. Results of host plant analysis with 17 plant species mostly resembled those expected for PepMV. Nucleotide sequence alignment of DNA fragments obtained by reverse-transcriptase polymerase chain reaction with a specific primer set for potexviruses, directed against the RNA polymerase region, showed 93% identity between PepMV and the virus from tomato, while homologies with PVX, PAMV, and other potexviruses were <60%. Results indicate that the potexvirus in tomato is PepMV. PepMV was first found in pepino (Solanum muricatum) in Peru in 1974 and described by Jones et al. in 1980 (1). This is the first report of a natural infection of tomato by PepMV. Reference: (1) R. Jones et al. Ann. Appl. Biol. 94:61, 1980.
Collar Rot and Wilt of Yellow Passion Fruit in Venezuela
Authors: Gonzalez M. S. , Suarez Z. , Rosales C. , Parra D. 
Published: May 2007

Surveys were conducted to determine the occurrence of diseases of yellow passion fruit (Passiflora edulis f. flavicarpa) in plantations located in the central states of Aragua, Carabobo, Guarico, Miranda, and Yaracuy, Venezuela, from 1991 to 1998. Plants in both commercial plantations and passion fruit nurseries were symptomatic for wilt and reddish-brown collar rot. Symptomatic tissues were surface-disinfected and plated on PARPH medium (1). Phytophthora parasitica was frequently isolated from diseased tissues, and pathogenicity tests were conducted with the fungus under greenhouse conditions. Passion fruit seedlings were grown in pots containing a 1:1 (vol/vol) steamed soil/sand mixture, one plant per pot. Five-millimeter-diameter plugs of P. parasitica isolates were grown on clarified V8 agar. Three-month-old seedlings were wounded with a sterile scalpel in the collar region. Wounded and unwounded plants were inoculated with 10 ml of zoospore suspension (105 spores per ml) or sterile water (control). Fifty plants were evaluated per treatment, and the experiment was repeated. Wounded and unwounded seedlings inoculated with zoospores developed chlorosis and collar necrosis after 15 days. Seedling mortality reached 50% 1 month after inoculation, and the fungus was reisolated from symptomatic tissues. This is the first report of P. parasitica causing collar rot and wilt of yellow passion fruit in Venezuela. Reference: (1) S. N. Jeffers and S. B. Martin. Plant Dis 70:1038, 1986.