bluuebunny/crossref_metadata_2025_split huggingface dataset:
A New Pathotype of Xanthomonas campestris pv. armoraciae That Causes Bacterial Leaf Spot of Radish
Authors: Sahin F. , Miller S. A. 
Published: May 2007

A previously undescribed pathotype of Xanthomonas campestris pv. armoraciae was found in 1995 on radish plants grown on organic soil in north central Ohio. Radish foliage developed numerous small, circular, water-soaked black spots, eventually with yellow halos, on the underside of the leaves, giving the foliage a yellowish, ragged appearance. Spots were also visible on the upper surface of leaves and on petioles. Yellow xanthomonad-like bacteria were consistently isolated from the lesions and confirmed as the causal agent of the disease by fulfilling Koch's postulates. All five strains purified were gram negative, rod shaped, motile, aerobic, oxidase negative, catalase positive, amylolytic, and pectolytic. They were identified as X. campestris pv. armoraciae by fatty acid methyl ester (FAME) analysis (similarity indices [SI] range = 0.21 to 0.39), the Biolog 95 GN reaction (SI range = 0.31 to 0.36), and serological reactions with X. campestris pv. campestris/X. campestris pv. armoraciae-specific monoclonal antibodies X9, X11, X21, A11, and B35 (1). All strains caused bacterial leaf spot on collard, kale, radish, horseradish, and cabbage but not on tomato or pepper. These strains were different from X. campestris pv. raphani, which is pathogenic on kale, radish, cabbage, tomato, and pepper, but not on horseradish. These strains also differed from other previously reported strains of X. campestris pv. armoraciae that do not cause infection on kale and radish (1,2). This is the first report on the existence of a different pathogenic group within X. campestris pv. armoraciae that can cause bacterial spot on kale and radish. References: (1) A. M. Alvarez et al. Phytopathology 84:1449, 1994; (2) H. E. White. Phytopathology 20:653, 1930.
Occurrence of Stem and Crown Rot of Gaillardia grandiflora, Caused by Sclerotinia sclerotiorum, in California
Authors: Koike S. T. 
Published: May 2007

Gaillardia grandiflora, or blanket flower, is a perennial, herbaceous composite used as an ornamental plant. Following a series of rains in January, 1997, landscape plantings of G. grandiflora in Monterey County, CA, exhibited symptoms of a previously undescribed disease. Affected stems turned gray to tan and became dry and brittle. Large branches often developed cracks. Attached leaves and flowers wilted and turned tan. Infections on the smaller stems and branches sometimes spread to the main stem and crown of the plant, resulting in plant death. White mycelia and large, irregular, black sclerotia (3 to 6 mm in diameter) were occasionally observed on external surfaces of infected stems and crowns. However, the internal pith cavity of diseased stems often contained abundant mycelia and sclerotia. Isolations from symptomatic stems, mycelia, and sclerotia produced colonies of Sclerotinia sclerotiorum. Pathogenicity was confirmed by culturing representative isolates on potato dextrose agar and allowing the fungus to colonize sterilized toothpicks placed on the surface of the agar (1). The pointed tips of the toothpicks were inserted approximately 3 mm deep into stems of potted G. grandiflora cv. Goblin plants, which were incubated in plastic bags for 48 h and then kept in a greenhouse. After 10 to 14 days, symptoms and mycelia similar to those originally observed developed on inoculated plants and S. sclerotiorum was reisolated. Stems on plants left for 21 or more days contained abundant sclerotia. Plants inoculated with sterile, uncolonized toothpicks did not develop disease. This pathogenicity test was repeated and the results were similar. This is the first report of G. grandiflora as a host of S. sclerotiorum. Reference: (1) Y. Yanar et al. Plant Dis. 80:342, 1996.
First Report of White Rust of Gerbera Caused by Albugo tragopogonis in North America
Authors: Vazquez G. L. , Aquino M. J. , Norman M. T. , Martinez F. A. , Sandoval R. V. , Corona R. M. C. , Strider D. L. 
Published: May 2007

In October, 1995, in Villa Guerrero, Mexico, white erumpent sori were detected on the undersurfaces of leaves of a bed of African daisy (Gerbera jamesonii H. Bolus ex J. D. Hook.). The white sori on the undersurfaces of leaves corresponded to chlorotic spots on the upper leaf surfaces. All gerbera plants examined were severely diseased. The gerbera planting was adjacent to a planting of chrysanthemums with symptoms of white rust caused by Puccinia horiana Henn. Symptoms on the leaves of the two crops looked similar, and therefore P. horiana was suspected of causing both diseases. However, when subepidermal sori (pustules) on Gerbera plants were examined microscopically, erumpent chains of round to cylindrical, hyaline to pale yellow sporangiospores borne on short club-shaped sporangiophores were found. The sporangiospores are typical of Albugo tragopogonis (Pers.) S. F. Gray, and it was concluded that the white rust found on gerbera in Villa Guerrero, Mexico, was caused by A. tragopogonis. This disease was reported on gerbera from Australia and New Zealand in 1965 (1) and from Spain in 1977 (2). Other hosts of A. tragopogonis include members in the genera Pericallis (cineraria), Centaurea (dusty miller, basket flower, cornflower, bachelor's-buttons), Ambrosia (common ragweed), Tragopogon (salsify), Antennaria (everlasting, pussytoes), Artemisia (wormwort, mugwort), Cirsium (thistle), Matricaria (false chamomile, pineapple weed), Iva (marshelder), Parthenium (guayule, American feverfew), and Xanthium (common cocklebur, spiny cocklebur). This is the first report of white rust of gerbera caused by A. tragopogonis in North America, and may represent a new disease problem for species of important floral crops in the future. References: (1) R. F. Doepel. J. Agric. West. Aust. Ser. 4 6:439, 1965. [Rev. Appl. Mycol. 45:80, 1966] (2) H. P. Plate and H. Kruber. Nachrichtenbl. Dtsch. Pflanzen-schutzdienst (Berlin) 29(11):169, 1977. [Rev. Plant Pathol. 57:204, 1978]
First Report of Sclerotinia sclerotiorum on Basil in Canada
Authors: Paulitz T. C. 
Published: May 2007

Wilt of basil (Ocimum basilicum L.) branches was observed in home gardens with a past history of Sclerotinia rot in Ste. Anne de Bellevue, Quebec, in the summers of 1994 and 1996. The wilt was accompanied by brown, longitudinal discoloration of the stem, with dark brown to purple-colored advancing margins. No rot or external mycelium was seen on mature woody portions of the wilted branches. Sclerotinia sclerotiorum (Lib). de Bary was isolated from wilted stems on 2% water agar and potato dextrose agar (PDA). Symptoms were reproduced in the greenhouse in 1995 and 1996 by inoculating stems of 10 1-month-old plants with mycelial plugs from 7-day-old PDA cultures. Wilt and necrosis of the outer layer of the inoculated stems were observed in all plants and the pathogen was reisolated from stems. During rainy periods in July 1996, sclerotia (3 to 6 mm diameter) formed on the stems and leaves of some infected plants in gardens. S. sclerotiorum has been reported in the U.S. on greenhouse-grown basil (1), but this is the first report from Canada and from field-grown plants. This disease may be confused with Fusarium wilt on mature plants, because of the dark discoloration of the stem, severe wilting, and lack of white, cottony mycelium. Reference: (1) G. E. Holcomb and M. J. Reed. Plant Dis. 78:924, 1994.
Delphinella balsameae Tip Blight of Abies lasiocarpa in Vermont
Authors: Merrill W. , Wenner N. G. , Kelley R. 
Published: May 2007

In 1996, a windbreak planting of Abies concolor (Gordon & Glend.) Lindl. ex Hildebr. and A. lasiocarpa (Hook.) Nutt. on a Christmas tree farm in Lamoille County, VT, incurred tip blight caused by a Delphinella sp. Although only scattered new shoots of the intermixed A. concolor and nearby A. balsamea (L.) Mill. were killed, more than 75% of the new shoots in the lower 1.8 m of the crowns of A. lasiocarpa were killed. This posed the question, whether the pathogen was the native D. balsameae (A. M. Waterman) E. Müller in E. Müller & Arx or whether the western species, D. abietis (Rostr.) E. Müller in E. Müller had been introduced. Dead 1996 shoots were collected from all species on 15 July. Most ascomata were immature. However, occasional ascomata bore well-developed bitunicate asci with hyaline, uniseptate ascospores averaging 40 × 9 μm, confirming the pathogen was D. balsameae (1). Funk reported this pathogen on A. lasiocarpa in British Columbia without documentation; this is the first record of it attacking this species in eastern North Amer-ica. Although the seed source was unknown, the extreme susceptibility of A. lasiocarpa in comparison to other Abies spp. in the area suggests that caution should be used in planting this species in the Northeast. Reference: (1) A. M. Waterman. J. Agric. Res. 70:315, 1943.
Incidence of Phoma terrestris, Causal Agent of Red Root Rot, in Corn Roots and Soil in Delaware and on the Eastern Shore of Maryland
Authors: Newby D. L. , Carroll R. B. , Whittington D. P. 
Published: May 2007

Red root rot of corn (Zea mays L.) has caused sporadic disease losses in Delmarva during the past 6 years. A survey was made between 21 August and 14 September 1995 in 11 counties in Delaware and on the eastern shore of Maryland to detect Phoma terrestris (E. M. Hans.) in corn roots and in the surrounding soil. Sampling was based on one field per 1,200 ha of corn production in each county. Three root samples and one soil sample were collected from each of 100 corn production fields from corn plants with diseased basal stalk tissue. The presence of P. terrestris was confirmed by cultures from root samples that produced a beet-red color on Watson's sterile wheat straw agar (2). Serial dilutions of soil samples in 0.1% water agar were mixed with unsolidified Watson's basal medium, followed by amendment with a 2-(4-thiazolyl)benzimidazole solution (1). P. terrestris was detected in root samples from 99% of the fields surveyed and from 82% of the soil samples. Soil populations ranged from 0.2 to 200 CFU per g of soil, with a mean of 12.5 CFU. This survey indicated that P. terrestris is widespread in corn production fields in Delaware and on the eastern shore of Maryland. Disease symptoms in surveyed fields indicated that pathogenicity on corn is variable, generally does not result in serious losses, and is related to hybrid susceptibility and growing conditions. References: (1) B. Sneh et al. Phytopathology 64:275, 1974. (2) R. D. Watson. Plant Dis. Rep. 45:289, 1961.
Occurrence of Peach Latent Mosaic Viroid (PLMVd) on Plum in Italy
Authors: Faggioli F. , Loreti S. , Barba M. 
Published: May 2007

Peach latent mosaic disease was originally described in France in 1976 (1). The disease is often latent in peach trees but may induce mosaic symptoms on leaves, irregularly shaped colorless fruit with cracked sutures and enlarged pits, bud necrosis, and delay in foliation, flowering, and fruit maturity. Recently, the disease has been shown to be caused by peach latent mosaic viroid (PLMVd) (2). PLMVd is distributed worldwide on peach. A recent survey in Italian plum orchards has showed the occurrence of PLMVd in two plum cultivars (Black Diamond and Angeleno) at different geographical locations in central Italy. Plum samples showed bark necrosis and bark split on branches and trunk; moreover, 1-or 2-year-old shoots and stem appeared dwarfed because of shortening of internodes and reduced growth. Budwood from plum samples were grafted, in greenhouse, onto peach GF305 indicator plants. Total nucleic acids (TNA) were then extracted from peach GF 305, or plum leaves, after 6 months of postinoculation. The presence or absence of PLMVd was ascertained by bidirectional polyacrylamide gel electrophoretic (dPAGE) analysis and by spot hybridization assay with PLMVd cRNA probe provided by A. Hadidi. A dPAGE analysis of TNA extracted from grafted peach GF305 showed a band with the same electrophoretic mobility as that of D-168 strain of PLMVd positive control. No bands were observed in healthy peach GF305 or from healthy or diseased plum extracts. The lack of detection of a viroid band from diseased plum samples by dPAGE analysis may be due to low titer of the viroid in infected plum. Molecular hybridization analysis of total nucleic acids with PLMVd cRNA probe, however, showed positive hybridization signals with nucleic acids from grafted peach GF305 or infected plum. Thus, PLMVd or a very closely related viroid infects plum trees. Moreover, on the basis of biological and serological assays, apple chlorotic leaf spot trichovirus, in a sample, and prunus necrotic ring spot ilarvirus, in the second one, were found in association with PLMVd. The same symptoms observed in the two PLMVd-infected plums occurred in other plants infected only by the two viruses (alone or in association). These data suggest that, very probably, PLMVd does not play a specific role in the etiology of the field symptomatology described above. In any case, this is the first report for the occurrence of PLMVd on plum in Italy. References: (1) J. C. Desvignes. Acta Hortic. 67: 315, 1976. (2) R. Flores and G. Llacer. Acta Hortic. 235:325, 1988.
First Report of Banana Streak Virus Infecting Banana Cultivars (Musa spp.) in Taiwan
Authors: Su Hong-Ji , Hung Ting-Hsuan , Wu Meng-Ling 
Published: May 2007

Banana (Musa sapientam L.) is an economically important crop for both export and local consumption in Taiwan. Recently, leaf symptoms characteristic of banana streak disease (1) were found on banana cv. Mysore (AAB group) introduced from Australia in the germ plasm collection of the Taiwan Banana Research Institute. The citrus mealybug (Planococus citri) has been shown to transmit banana streak virus (BSV) but not banana bunchy top virus or cucumber mosaic virus (CMV) (2). When mealybugs were fed on leaves of diseased Mysore banana and transferred to healthy banana cv. Cavendish seedlings in a growth chamber, the latter developed fine chlorotic streaks characteristic of symptoms caused by BSV within 1 to 3 months. Some chlorotic streaks became necrotic. BSV was detected in diseased but not healthy leaves of Mysore and Cavendish bananas by polymerase chain reaction (PCR) with primer pairs of BSV provided by J. E. Thomas of Queensland Department of Primary Industries. Subsequently, fine chlorotic streaks were observed in leaves of Cavendish banana in several fields in southern Taiwan. Some of these diseased plants developed severe leaf necrosis, causing heart rot of spindle leaves characteristic of symptoms caused by CMV. Presence of BSV in these plants was verified by PCR assay. However, CMV was also detected by double antibody sandwich-enzyme-linked immunosorbent assay with a monoclonal antibody to CMV, indicating that these plants were simultaneously infected by both viruses. This is the first report of BSV infecting Musa spp. in Taiwan. References: (1) B. E. L. Lockhart. Phytopathology 76:995, 1986. (2) B. E. L. Lockhart. 1995 Food & Fertilizer Technol. Center (ASPAC) Tech. Bull. 143. 11 pp.
Citrus Blight Found in Yucatan, Mexico
Authors: Wutscher H. K. , Cervantes H. A. , Derrick K. S. 
Published: May 2007

Citrus blight, a serious tree decline problem of unknown cause in humid citrus-growing areas such as Florida and Louisiana, South America, South Africa, and the Caribbean, has never been reported from Mexico. Citrus blight has no reliable visual symptoms, and physical and chemical tests have to be used for diagnosis. We used water injection into the trunk (2), zinc and potassium analysis of the outer trunk wood (3), and an immunological test for specific blight proteins in the leaves (1). Low uptake when water is injected into the trunk, and high zinc and potassium in the wood, compared with healthy trees, are characteristic of citrus blight (3). Water injection tests and wood analysis of four healthy and four declining trees in the Dzan, Yucatan, Mexico, area in August 1995, showed highly significant differences in water uptake (healthy trees 44.3 ml/min, declining trees 1.0 ml/min), little difference in wood zinc (healthy 2.8 μg/g, declining 3.0 μg/g) and 39% more potassium in the wood (healthy 0.147%, declining 0.204%). No leaf protein tests were done at this location. Tests on eight declining and five healthy trees in Seye, Yucatan, Mexico, in June 1996, showed significant (P = 0.01 to 0.05) differences in water uptake (healthy 12.9 ml/min, declining 0.6 ml/min), in wood zinc (healthy 2.0 μg/g, declining 7.0 μg/g) and potassium in the wood (healthy 0.156%, declining 0.251%). Leaf samples from all eight declining trees were positive for blight in a specific protein test (1). The visual symptoms of all declining trees tested were the same as those of blight-affected trees in Florida and Cuba: zinc deficiency symptoms in the leaves, thin foliage, wilt, and sprouting from the trunk and the main branches. The reasons for the lack of earlier reports of citrus blight from Mexico are apparently climatic and rootstock related. Many of Mexico's citrus-producing areas are dry and blight does not occur in dry areas such as the Mediterranean countries and California. Most of Mexico's citrus is grown on sour orange (Citrus aurantium L.) rootstock that is highly resistant to citrus blight, but very susceptible to tristeza virus disease. In response to warnings that tristeza disease might appear in Yucatan, growers planted Valencia orange (C. sinensis (L.) Osbeck) on Cleopatra mandarin (C. reticulata Blanco) rootstock in Dzan and on Volkamer lemon (C. limon (L.) N. L. Burm.) in Seye, both highly susceptible to citrus blight (4). Changes in rootstock to avoid one disease led to problems with another. References: (1) K. S. Derrick et al. Proc. Fla. State Hortic. Soc. 105:26, 1993. (2) R. F. Lee et al. Plant Dis. 68:511, 1984. (3) H. K. Wutscher and C. J. Hardesty. J. Am. Soc. Hortic. Sci. 104:9, 1979. (4) R. H. Young et al. Proc. Fla. State Hortic. Soc. 91:56, 1978.
Cloning and Sequencing of the Coat Protein Gene of a New Isolate of Citrus Tristeza Virus from Mexico
Authors: Cepeda-Nieto A. C. , Barrera-Saldaña H. A. 
Published: May 2007

Citrus tristeza virus (CTV) causes one of the most important citrus diseases. CTV strains cause a wide range of symptoms in infected citrus worldwide. Although it has not yet affected Mexico's citrus industry, CTV constitutes a threat since one of its most efficient vectors, Toxoptera citricida, is migrating north from South America and is now in the Caribbean region. Efforts have been made to prevent spread of the virus, through early detection with serological methods (3). Use of the polymerase chain reaction (PCR), not yet a competitor of immunological methods in field diagnosis of CTV, offers a quick detection alternative. As a first step toward using PCR in early diagnosis and characterization of CTV, we searched for the CTV coat protein gene in experimentally infected leaves of Citrus aurantifolia grown at a government research station (INIFAP) at General Terán, NL. Researchers at General Terán had collected the isolates during a random sampling of orange orchards in the Gulf state of Veracruz. The original orange trees had no apparent symptoms and had been examined as a preventive measure. Several of the original orange trees were CTV positive in their initial tests with polyclonal antibody and in subsequent tests with CTV-specific monoclonal antibody MCA-13. Characteristic CTV-like particles had also been observed by electron microscopy. The only symptom induced in indicator plants was yellowing of the leaf veins. In our laboratory, reverse transcription of RNA from one of the indicator plants, coupled with PCR (RT-PCR) (1), was used to clone and sequence one of the isolates to confirm the CTV identification and establish PCR methods. Oligonucleotide primers were derived from published sequences, but unique restriction enzyme sites (EcoRI and XbaI) were added to their 5′ ends to facilitate cloning. To exclude artifacts, nucleotide sequences were obtained from both strands after cloning in M13 vectors. Although the expected RT-PCR product of 700 bp was obtained, an unexpected EcoRI site was found at position 678 of the coat protein gene. A phenylalanine residue was found at position 124, as in severe strains of CTV from various regions of the world (2). Similarities between our CT sequence (U32116) and those of other GenBank accessions are as follows: 91.17% for M76485; 90.14% for L12175; and 89.32% for S67800. References: (1) M. D. Jones and N. S. Foulkes. Nucleic Acids Res. 17:8387, 1989. (2) H. Pappu et al. Proc. Natl. Acad. Sci. USA. 90:3641, 1993. (3) C. Vela et al. J. Gen. Virol. 67:91, 1986.
First Report of Colletotrichum capsici on Bell Pepper in Mississippi
Authors: Roy K. W. , Killebrew J. F. , Ratnayake S. 
Published: May 2007

Anthracnose (ripe rot) of bell pepper (Capsicum annuum L.), caused by Colletotrichum capsici (Syd.) E. J. Butler & Bisby, was observed in seven home gardens in Copiah, DeSoto, and Oktibbeha counties in Mississippi in 1994. Falcate conidia measuring 20.5 × 4.0 μm were produced on lesions of fruits in moist chambers. Conidial size and other distinguishing features agreed with the description of C. capsici (1). Pure cultures of the pathogen were obtained by aseptic transfer of conidia to agar. Occurrence of symptomatic fruits in gardens ranged from 15% in Starkville to 3% near Crystal Springs, MS, but nine of the gardens inspected had no fruit rot. The most severe disease occurred on ripening fruits. Lesions similar to those observed were produced by inoculating sterilized toothpick tips infested with C. capsici into fruits, followed by incubation in a moist chamber. Koch's postulates were completed by reisolation of the fungus from inoculated fruits. Reference: (1) J. E. M. Mordue. 1971. No. 317 in: Descriptions of Pathogenic Fungi and Bacteria. Commonw. Mycol. Inst., Kew, England.
Detection of Both Subgroups I and II of Cucumber Mosaic Cucumovirus and Their Satellite RNAs on Pepper in Argentina
Authors: Atencio F. A. , Gracia O. , Mendoza E. E. A. , Zandomeni R. , Grau O. 
Published: May 2007

Pepper plants (Capsicum annuum L.) showing stunting, mild to severe mosaic, leaf narrowing and deformation, prominent veins, fruit atrophy or malformation, and necrotic patterns on leaves and fruits were collected from commercial and experimental farms from seven districts in the central western neighboring provinces of Mendoza and San Juan. Cucumber mosaic cucumovirus (CMV) was identified directly from field samples from crude RNA extracts by reverse transcription-polymerase chain reaction (RT-PCR) (1). The PCR-amplified products were analyzed by restriction enzyme digestion with PvuII and VspI to distinguish the CMV subgroups. Serological assays (double immunodiffusion tests and indirect triple antibody sandwich enzyme-linked immunosorbent assay) with subgroup-specific monoclonal and polyclonal antisera also differentiated between the subgroups, although with lower sensitivity than found with PCR. Both subgroups I and II were found, no mixed infections were detected, and subgroup membership was related to geographical distribution: subgroup-I samples were detected in San Juan sites (north), and samples collected from the southern area (Mendoza) were of subgroup II. Some samples were sap-transmitted and passed repeatedly through tobacco and pepper. Satellite RNAs (satRNAs) were detected from total RNA extracts by RT-PCR with specific primers (5′-end oligonucleotide: 5′GGGTTATATCTGCGTGAG3′ and 5′CACGGAGATCAGCATAGC3′ as 3′-end primer). One satRNA isolate from each area was amplified and cloned. Three and five clones, respectively, were sequenced, obtaining 313/315 nucleotide and 334 nucleotide consensus sequences that appear to be similar (98.2 and 98.9%, respectively) to CMV-Y satRNA. This is the first report of CMV subgrouping and detection of CMV satRNAs in Argentina. Reference: (1) H. Rizos et al. J. Gen. Virol. 73:2099, 1992.