bluuebunny/crossref_metadata_2025_split huggingface dataset:
First Report of the Telial Stage of Gymnosporangium exiguum on Ashe Juniper Adjacent to Hawthorn with Rust in Southwest Texas
Authors: Black M. C. , Grand L. F. , Vernia C. S. 
Published: May 2007

The telial stage of Gymnosporangium exiguum (2) on Ashe juniper (Juniperus ashei) was observed in Bandera County, TX, in April and May 1999 after rain events. Symptomatic plants with multiple lesions were found at low frequencies in dense J. ashei populations. Orange telia formed on scales and bark and on 2- to 3-mm-diameter twigs and became nearly inconspicuous when dry. No hypertrophy was observed. Previously reported telial hosts include J. californica and J. excelsa cv. Stricta in California; J. mexicana and J. scopulorum in Oklahoma; J. virginiana in Texas; and J. deppeana var. pachyphloea in Oklahoma and Texas (1). An aecial stage identified as G. exiguum has been observed for many years on native hawthorns (Crataegus crus-galli, C. greggiana, C. mollis, C. stevensiana, C. tracyi, C. turnerorum, C. viridis var. desertorum, and several natural hybrids) in Bandera, Bexar, Edwards, Gillespie, Kendall, Kimble, Real, and Uvalde counties, Texas. Prominent roestelioid aecia were observed on hawthorn leaves, petioles, fruits, peduncles, thorns, and, less often, on twigs. In two experimental plantings of hawthorns in Bandera County, rust severity was rated as low to moderate in six populations of C. greggiana and hybrids; moderate in two populations each of C. stevensiana and C. tracyi; moderate to severe in three populations of C. crus-galli and hybrids; and severe in one population each of C. mollis and C. viridis var. desertorum. G. exiguum was previously reported on a Crataegus sp. in Texas and on Heteromeles arbutifolia in California (1). Flowers, fruits, plant forms, and drought tolerances are characteristics of some endemic hawthorns that provide landscape and wildlife advantages. G. exiguum causing rust disease may limit the ornamental potential of highly susceptible hawthorn species in southwest Texas. Inconspicuous infections on susceptible ornamental Juniperus spp. also could have phytosanitary implications. Voucher specimens (aecia and telia) are on deposit in the Mycological Herbarium, Department of Plant Pathology, North Carolina State University, Raleigh. References: (1) D. F. Farr et al. 1989. Fungi on Plants and Plant Products in the United States. The American Phytopathological Society, St. Paul, MN. (2) F. D. Kern. 1973. A Revised Taxonomic Account of Gymnosporangium. The Pennsylvania State University Press, University Park.
A Foliar Disease of European Hackberry Endemic in Sicily
Authors: Cacciola S. O. 
Published: May 2007

European hackberry (Celtis australis L.; Ulmaceae), a semideciduous tree or shrub that produces small edible berries was originally grown in Italy to produce charcoal and timber and was particularly suitable for making whipstocks, carriage wheel spokes, and hoe handles. European hackberry is currently used for reforestation and as shade trees in parks and roadside plantings. Recently, a foliar disease caused by the dematiaceous hyphomycetous fungus Sirosporium celtidis (Biv.-Bern. ex Sprengel) M.B. Ellis on hackberry saplings in a nursery was observed in the Piedmont Region (northern Italy) by Giannetti et al. (2), who referred to it as a rare disease. However, during a survey in the nature reserve of the Anapo River Valley, in the Sicily Region (southern Italy), where European hackberry and a closely related species (C. tournefortii Lam.) grow naturally, most hackberry plants were found to be infected by S. celtidis, with variable intensity. During autumn, symptoms appeared on lower leaf surfaces as reddish brown to dark black-brown subcircular velvety spots (up to 10 to 15 mm wide) surrounded by narrow paler margins that were evenly distributed over the leaf surface and later confluent. Nonspecific symptoms on upper leaf surfaces were visible only in advanced stages and consisted of necrotic areas, usually apical or marginal, that were at first red-brown and later turned gray. A few trees were prematurely defoliated. Usually, however, severely affected leaves were necrotic, withered, and curled but remained attached. Spots on lower leaf surfaces were covered by mycelium, conidiophores, and conidia that corresponded to the description of S. celtidis published by Ellis (1). Conidia were straight, flexuous, occasionally markedly curved or coiled, cylindrical or obclavate, smooth, wrinkled or verrucose, subhyaline to golden or reddish brown, typically multicellular with 1 to 32 transverse septa, and occasionally had longitudinal or oblique septa that were often constricted, more than 100 μm long and up to 5 to 8 μm thick, with an inconspicuous scar at the base. From 1997 to 1999, infection by S. celtidis in the Anapo River Valley occurred each year, probably favored by the moist environment. S. celtidis, first described in Sicily as early as 1815 (1), has been recorded on various hackberry species in many countries, including the United States (3). Apparently this pathogen is of little economic and ecological significance in natural ecosystems; however, the fungus could become a serious problem in nurseries (2). References: (1) M. B. Ellis. 1963. Mycological Papers, No. 87. Commonw. Mycol. Inst. Kew, England. (2) G. Giannetti et al. Inform. Fitopatol. 49:39, 1999. (3) D. H. Linder. Ann. Mo. Bot. Garden 18:31, 1931.
First Report of Phytophthora Root Rot of Sugar Beet, Caused by Phytophthora cryptogea, in Greece
Authors: Karaoglanidis G. S. , Karadimos D. A. , Klonari K. 
Published: May 2007

A severe rot of sugar beet roots was observed in the Amyndeon area of Greece during summer 1998. Infected plants initially showed a temporary wilt, which became permanent, and finally died. Slightly diseased roots showed necrotic spots toward the base, whereas more heavily diseased roots showed a more extensive wet rot that extended upward. Feeder roots also were infected and reduced in number because of decay. Rotted tissue was brown with a distinguishing black margin. In most of the isolations, carried out on potato dextrose agar (PDA), the pathogen obtained was identified as Phytophthora cryptogea Pethybr. & Lafferty Mycelium consisted of fairly uniform, fine hyphae that showed a slightly floral growth pattern. In autoclaved soil-extract medium, chains or clusters of hyphal swellings (average 12 µm diameter) formed. Sporangia were not produced on solid media but were abundant in soil-extract medium. Sporangia were oval to obpyriform in shape, nonpapillate with rounded bases, and varied in size (39 to 80 × 24 to 40 µm). Oospores were plerotic, thick-walled, and averaged 25 µm in diameter. The isolated pathogen, cultured on PDA, could not grow at all at 36°C. The closely related species P. drechsleri Tucker has been reported to cause similar root rot symptoms on sugar beet (3). However, P. drechsleri grows well at 36°C, while P. cryptogea cannot grow at this temperature; this is the major distinguishing feature that separates the two species (1). To test the pathogenicity of the organism, surface-sterilized sugar beet roots (cv. Rizor) were inoculated with 5-mm-diameter PDA plugs containing actively growing mycelium. Sterile PDA plugs were used to inoculate control sugar beet roots. Inoculated roots were kept at 27°C in the dark for 10 days. Extensive decay of inoculated roots developed, similar to decay observed in the field, whereas control roots showed no decay. P. cryptogea was reisolated from rotted tissues. This pathogen has been recognized previously as a cause of root rot of sugar beet in Japan (1) and Wyoming (2). This is the first report of Phytophthora root rot of sugar beet in Greece. References: (1) D. C. Erwin and O. K. Ribeiro. 1996. Phytophthora Diseases Worldwide. The American Phytopathological Society, St. Paul, MN. (2) P. C. Vincelli et. al. Plant Dis. 74:614, 1990. (3) E. D. Whitnew and J. E. Duffus, eds. 1986. Compendium of Beet Diseases and Insects. The American Phytopathological Society, St. Paul, MN.
First Report of Phomopsis vexans on Apricot in the Americas
Authors: Bello G. Dal , Sisterna M. 
Published: May 2007

Prunus armeniaca L. plants with blight symptoms on leaves and twigs were observed near La Plata (Argentina) in 1999. On leaves, symptoms ranged from small (up to 4 mm diameter) and dispersed brown circular spots to irregular blighted areas with numerous pycnidia. Twig blight developed initially on buds as necrosis that expanded and caused shoots to wilt. A Phomopsis sp. was isolated from necrotic tissues. Pathogenicity was assessed by inoculating healthy mature leaves with a spore suspension (1 × 106 conidia per ml). Detached sterile twigs were placed in Roux tubes with water (1) and were infected by needle-stab inoculation. Controls were treated with sterile water. Inoculated leaves and controls were left in bags for 48 h. After 5 to 14 days, symptoms were similar to those described for field samples. The Phomopsis sp. was reisolated from necrotic lesions and characterized as identical to the original isolates. On potato dextrose agar, the fungus had white floccose mycelium and produced numerous black, globose to irregular pycnidia (up to 300 µm). Alpha-conidia were one-celled, hyaline, and ellipsoidal (4.5 to 10.3 µm long × 1.8 to 2.1 µm wide); beta-conidia were one-celled, hyaline, filiform, and straight or curved (16.8 to 27.5 µm long × 1.0 µm wide). A pure culture was identified as Phomopsis vexans (Sacc. & Syd.) Harter based on morphology and host specificity. This is the second report of P. vexans on apricot since the disease was cited in Algeria (2). References: (1) T. A. Gally. Fitopatologia 10:87, 1975. (2) D. V. Narendra et al. FAO Plant Prot. Bull. 27:132, 1979.
First Report of Fusarium Wilt on Hebe sp. in Italy and Europe
Authors: Garibaldi A. , Minuto A. , Gilardi G. , Gullino M. L. 
Published: May 2007

Hebe (showy speedwell), an increasingly important crop in the Riviera Ligure (northern Italy), is cultivated in greenhouses and open fields. During summer 1999, a serious wilt of hybrids (Hebe speciosa × H. franciscana cvs. Paula, Linda, and Heidi) grown in plastic pots (14 to 16 cm diameter) in a peat/pomix/clay (70:20:10, vol/vol) substrate was observed. Symptoms appeared on one side of the plant or on a single branch. Affected plants showed only slight yellowing before wilting. Wilting progressed acropetally. Eventually, affected plants were completely wilted, and stems showed dark blue-black necrosis, often covered by mycelia. An intense brown discoloration of the vascular system was evident shortly after the appearance of the first symptoms. In some cases, whole plants suddenly wilted. Infected plants generally were stunted and eventually died. Fusarium oxysporum was isolated consistently from diseased plants on Komada's (1) Fusarium-selective medium. One single-spore isolate of F. oxysporum, freshly isolated from wilted plants, was used for artificial inoculation of healthy plants to complete Koch's postulates. Rooted cuttings were transplanted in soil artificially infested with 1 × 103 CFU/ml of soil. Inoculation was performed on 20 plants belonging to two cultivars (Paula and Heidi). Noninoculated plants of each cultivar served as controls. Plants were maintained in a glasshouse at 25°C. The first symptoms developed 20 days after transplanting in infested soil. Symptoms resulting from artificial inoculation were similar to those observed on naturally infected plants. F. oxysporum was consistently reisolated from inoculated plants. Fusarium wilt of Hebe is favored by temperatures higher than 20°C. Symptoms did not develop on inoculated plants maintained in the open field during the month of October nor in the greenhouse at temperatures lower than 18°C. This is the first report of Fusarium wilt on Hebe sp. in Italy and Europe. A similar wilt on H. buxifolia and other Hebe spp. has been reported by Raabe in the United States (2,3). References: (1) H. Komada. Rev. Plant Prot. Res 8:114, 1975. (2) R. D. Raabe. Phytopathology 47:532, 1957. (3) R. D. Raabe. Plant Dis. 69:450, 1985.
Yellow Leaf Disease of Muskmelon from Thailand Caused by Tomato leaf curl virus
Authors: Samretwanich K. , Chiemsombat P. , Kittipakorn K. , Ikegami M. 
Published: May 2007

Muskmelon (Cucumis melo L. var. reliculatus) plants exhibiting a yellow leaf disease have been observed in central Thailand since 1993. The pathogen is transmitted to muskmelon by the whitefly, Bemisia tabaci Genn. Based on leaf yellowing symptoms and whitefly transmission, infection by a geminivirus was suspected. Five naturally infected musk-melon plants showing leaf yellowing were collected from a field at Kam-phaengsaen, Nakorn Pathom, Thailand, in 1996. Virus cultures were maintained in muskmelon plants in a screenhouse. Inoculations were done with B. tabaci, and leaf symptoms were the same as symptoms in the field. Geminivirus DNA associated with yellow leaf disease of musk-melon was amplified by polymerase chain reaction with geminivirus-specific degenerate primers (2) that anneal within the rep (replication-associated protein) and cp (coat protein) genes (2). Fragments of 1.2 kb were amplified and cloned from affected muskmelon plants. The insert of three independent clones was sequenced, and identical 32-base stem loop regions were found, including the conserved nonanucleotide sequence TAATATTAC present in all geminiviruses. The iterative sequence GGCGTC also was found in the intergenic region (IR; 434 bp) of the amplified fragments (1). The B component was not found from the total length of the restriction fragment sizes of dsDNA isolated from infected muskmelon. The nucleotide sequences of IR and V1 (precoat open reading frame) were compared with 28 well-studied whitefly-transmitted geminiviruses and revealed ≍97% sequence similarity with DNA A of Tomato leaf curl virus (genus Geminivirus) from India (ToLCV-In2; GenBank Accession no. u15016) (1). The iterative sequence GGCGTC in the IR also was identical to ToLCV-In2. These results establish the provisional identity of the virus causing melon yellow leaf disease as ToLCV or closely related strains. References: (1) M. Padidam et al. J. Gen. Virol. 76:249, 1995. (2) M. R. Rojas et al. Plant Dis. 77:340, 1993.
Cucurbit leaf curl virus, a New Whitefly Transmitted Geminivirus in Arizona, Texas, and Mexico
Authors: Brown J. K. , Idris A. M. , Olsen M. W. , Miller M. E. , Isakeit T. , Anciso J. 
Published: May 2007

In 1998 to 1999, geminivirus-like symptoms were observed in whitefly-infested pumpkin, honeydew melon, and muskmelon in Arizona and Texas and in Coahuilla, Mexico (MX), respectively. Plants exhibited leaf curl and/or mottling, reminiscent of symptoms caused by Squash leaf curl virus (SLCV-WAZ) described from Arizona in 1981 (2). The isolate from Arizona pumpkin fields was experimentally transmitted to pumpkin seedlings by the “B type” of Bemisia tabaci (Genn.), and symptoms were indistinguishable from those observed in infected fields. Samples from AZ, MX, and TX were assessed for begomovirus presence by polymerase chain reaction (PCR) using degenerate primers that amplify a contiguous fragment containing the viral coat protein (Cp) gene and common region (CR) of the A component (CR-A) (~2,100 bp) and a fragment containing the CR of the B component (CR-B) (~1,100 bp). One to four isolates from each location were examined by PCR using both primer pairs, and at least three amplicons per isolate were cloned and their sequences determined. Alignment of viral Cp nucleotide (nt) sequences revealed that AZ [AF256199], MX, and TX field isolates shared 98.7 to 100% sequence identity, but were only 84.5 to 85.6% identical to the Cp gene of SLCV-extended (SLCV-E) [M38183] and SLCV-restricted (SLCV-R) (S. G. Lazarowitz, unpublished), respectively, suggesting a new, previously undescribed begomoviral species (3). Further, the Cp nt sequence of the three field isolates was 6 nt shorter than SLCV-E, SLCV-WAZ [AF256203], and SLCV-R Cp sequences. The CR-A [AF256200] and CR-B [AF256201] sequences (179 nt, each) of field isolates, including the theoretical Rep binding element, GGTGT, were 100% identical. Although the Rep binding site is identical among field isolates, SLCV-E, SLCV-R, and SLCV-WAZ, the field isolate CR sequence shared only 64.2, 67.5, and 66.9% overall identity with CR-A SLCV-E, SLCV-R [M63155], and SLCV-WAZ [AF256202], respectively. Prior to 1998 to 1999, SLCV-WAZ was the only New World begomovirus of cucurbits known to infect both melon (Cucumis) and pumpkin (Cucurbita) (1). Therefore, SLCV was initially suspected as the causal agent. However, here we provide evidence for a new, previously undescribed bipartite begomovirus of cucurbits in AZ, MX, and TX that is herein provisionally designated Cucurbit leaf curl virus (CuLCV). Prediction of its closest begomovirus relatives by Cp nt sequence and Rep binding site comparisons suggest that CuLCV is a new member of the SLCV lineage, also containing Bean calico mosaic virus, Cabbage leaf curl virus, SLCV-E, and Texas pepper virus-TAM. References: (1) J. K. Brown and M. R. Nelson. Phytopathology 74:1136, 1984. (2) J. K. Brown and M. R. Nelson. Ann. Appl. Biol. 115:243, 1986. (3) M. A. Mayo and C. R. Pringle. J. Gen. Virol. 97:649, 1998.
First Report of Pre- and Postemergence Damping-off of Cowpea Caused by Pythium ultimum in South Africa
Authors: Aveling T. A. S. , Adandonon A. 
Published: May 2007

During a disease survey of cowpea (Vigna unguiculata (L.) Walp.) in Southern Africa in 1999, a major problem recorded by small-holder rural farmers in areas with wet soil types was reduced seedling emergence. Nongerminated, diseased seeds in these fields were either a brown blotchy color or had a soft rot and disintegrated upon touch. Germinated seedlings failing to emerge above the soil line were characterized by water-soaked lesions girdling the hypocotyl. Emerged seedlings had necrotic taproots and few lateral roots. Infected hypocotyls above the soil line had light brown lesions, and seedlings showed symptoms of wilting. Diseased seeds and seedlings were collected, surface-sterilized, plated on 2% water agar, and Pythium ultimum was isolated. Identification was based on characteristics given in van der Plaats-Niterink (1). Sterile soilbased compost, infested by mixing with P. ultimum mycelia (10 CFU/g of compost), was used to fill 104-cell plastic seedling trays (40 × 28 × 3.5 cm). A single cowpea seed was planted at a depth of 2 cm in each cell, and trays were maintained in a greenhouse at approximately 20°C. Seeds and seedlings showed symptoms identical to those in the field 10 days after planting, and the pathogen was successfully reisolated. Seedlings in noninoculated compost remained symptomless. This is the first report of P. ultimum on cowpea in South Africa. Reference: (1) A. J. van der Plaats-Niterink. Monograph of the Genus Pythium. Centraalbureau voor Schimmelcultures, Baarn, 1981.
First Report of Bean common mosaic necrotic virus Infecting Bean Plants in Aguascalientes and Veracruz, Mexico
Authors: Flores-Estévez N. , Silva-Rosales L. , Acosta-Gallegos J. A. 
Published: May 2007

Bean common mosaic necrosis virus (BCMNV) is a pathogen of Phaseolus vulgaris L. BCMNV was previously classified in serogroup A (for necrotic strains) of the Bean common mosaic virus (BCMV) subgroup; serogroup B included non-necrotic strains of BCMV. Both serogroups are currently classified as two different species in the BCMV subgroup of the Poytvirus genus; strains of either species will produce mosaic symptoms and, in the presence of hypersensitive I gene, necrosis in bean plants (1). Prior to this classification, BCMV was reported in Mexico by the presence of mosaic and necrotic symptoms (2). To investigate the presence of BCMNV in Mexico, samples were collected in two of the main bean producing states. The total extracted RNA was used for reverse transcription polymerase chain reaction using primers complementary to the middle portion of the NIa gene (5') and the 3' UTR of the NL3 Michigan isolate (accession number U19287). Two cDNA segments of 2 and 3 kb were obtained from infected plants from the state of Aguascalientes, in the highlands of central Mexico, and from the state of Veracruz, in the lowlands of the Gulf of Mexico, respectively. The cDNAs were cloned and sequenced. Alignment analysis of these sequences with the NL3 strain of BCMNV showed a similarity of 96.4 and 96.7%, respectively. The similarity between the Aguascalientes (accession number AJ01265) and Veracruz isolates was 99.6%, indicating that both are variants of the same species. On the other hand, alignment analysis of these isolates with some published BCMV strain sequences (i.e., accession numbers L15332 and U55315) displayed low similarities of 52.9 and 64.4%, respectively. These comparisons indicate that the Aguascalientes and Veracruz viral isolates belong to the BCMNV species and is the causal agent of mosaic and necrosis observed on the bean plants in those states. References: (1) C. W. Collmer et al. Mol. Plant-Microbe Interact. 9:758, 1996. (2) E. Jimenez-García. SARH. Mexico. D. F. pp: 3–4, 1994.
Occurrence of Puccinia xanthii on Sunflower in South Africa
Authors: Pretorius Z. A. , van Wyk P. S. , Kriel W. M. 
Published: May 2007

A severe outbreak of a foliar disease occurred on ornamental sunflower (Helianthus annuus L. cv. Tyao) cultivated under plastic protection near Potchefstroom in the North West Province during February 2000. According to previous descriptions of host range, symptoms, and spore morphology, the pathogen was identified as the microcyclic rust fungus, Puccinia xanthii Schwein. (2–4). Telia, reaching 9 mm in diameter and often coalescing to form larger lesions associated with chlorosis, occurred on the lower surface of leaves. Symptoms were first observed at the V-12 growth stage when approximately 40% of leaves displayed lesions. The disease subsequently spread to younger plants (V-2 stage) where an incidence of 100% was recorded. Severity estimates regularly reached 50% leaf area affected. The primary source of inoculum was thought to be nearby rust-infected Xanthium strumarium sensu lato (burweed or cocklebur) plants, a known host for P. xanthii (2,4). Infection studies were carried out on 3-week-old sunflower plants using a mini settling tower supporting an inverted water agar plate containing leaf disks with P. xanthii telia (2) obtained from either sunflower or burweed. Plants covered with a settling tower were kept in the dark in a dew chamber for 48 h. Microscopic examination of inoculum from both sources confirmed germination of teliospores and formation of basidiospores. Test entries had similar disease reactions regardless of whether inocula were collected from H. annuus or X. strumarium. Fleck symptoms were visible on the hybrids SNK 77 and Orit 5 days after placing plants in the dew chamber. On these entries, telia gradually increased in size, indicating susceptibility to P. xanthii. Furthermore, those leaves receiving high inoculum dosages were desiccated 11 days after inoculation. Hybrids Hysun 333 and CRN 1470 and the male sterility maintainer lines DC 4 and RK 74 produced resistant reactions. Hyperplasia of stem and petiole tissue was observed on certain Orit, DC 4, and CRN 1470 plants. Susceptibility of burweed, a common and widespread annual weed in southern Africa (1), to a sunflower isolate of P. xanthii, was also confirmed. Depending on the formation of teliospores, the identity of the causal organism was verified in all inoculation studies. P. xanthii damage on sunflower has not been reported from South Africa. However, the disease has now become economically important as severe foliar lesions rendered plants unacceptable for the ornamental sunflower market. References: (1) C. Bromilow. 1995. Problem Plants of South Africa. Briza Publications, Pretoria, South Africa. (2) L. Morin et al. Can. J. Bot. 71:959, 1993. (3) L. Morin et al. Mycol. Res. 96:661, 1992. (4) J. Parmelee. Can. J. Bot. 47:1391, 1969.