bluuebunny/crossref_metadata_2025 huggingface dataset:
First Report of Bacterial Wilt of Annual Bluegrass Caused by Xanthomonas translucens pv. poae in Montana
Authors: Mitkowski N. A.
Published: May 2007

During August 2003, a golf course putting green sample composed of Poa annua from the Buffalo Hill Country Club in Kalispell, MT exhibiting symptoms of general decline, wilting, and necrosis was submitted to the University of Rhode Island Turfgrass Disease Diagnostic Laboratory. No pathogenic fungi were observed or cultured from affected plants. Bacterial streaming was observed from cut leaves. Cut leaves were surface disinfested for 5 min in a 0.6% sodium hypochlorite solution and plated on yeast dextrose calcium carbonate (YDC) agar media. A single yellow, mucoid colony type composed of rod-shaped bacteria was isolated from all leaves. Bacteria were gram negative, lacked anaerobic growth, did not fluorescence on King's medium B, and were able to grow at 33°C on YDC. Colonies were transferred to YDC for 10 days, DNA was extracted and a 2,190-bp region encompassing the 16S rRNA, ITS, and 5′ end of the 23S rRNA was amplified via polymerase chain reaction (PCR) using previously published protocols (1). Sequence comparisons of the resulting 2,190-bp PCR product revealed a 99.7% sequence similarity with X. translucens pv. poae (American Type Culture Collection [ATCC] no. 33804) and a 99.8% sequence similarity with X. translucens pv. poae M-1 (Torrington, CT). No higher sequence similarity could be identified from a BLAST search. The Montana isolate and the previously described M-1 isolate were inoculated onto four replicates of 5-month-old P. annua var. annua plants by dipping cut leaves into a bacterial suspension adjusted to 109 CFU/ml in 0.9% NaCl. Control plants were dipped into 0.9% NaCl without the presence of the bacteria. All plants were placed in the greenhouse at an average daytime temperature of approximately 24°C and 12 h of sunlight. After 8 weeks, the plants were assessed for disease and checked for bacterial streaming. This experiment was repeated once. The Montana isolate caused approximately 68 and 70% leaf death and the M-1 isolate caused 21 and 25% leaf death in the two experiments. Bacterial streaming was observed in approximately 50 and 80% of the examined leaves inoculated with the M-1 and Montana isolates, respectively. Control plants showed no leaf mortality or bacterial streaming. Although this pathogen was originally identified in the United States in Michigan (2) and has been prevalent in the northeastern United States for the past 10 to 15 years, to our knowledge, this is the first report of the disease in the northwestern United States.

References: (1) N. A. Mitkowski et al. Plant Dis. 89:469, 2005. (2) D. L. Roberts et al. Phytopathology 75:1289, 1985.
Influence of Environment on Atmospheric Concentrations of Peronospora antirrhini Sporangia in Field-Grown Snapdragon
Authors: Byrne J. M. , Hausbeck M. K. , Sconyers L. E.
Published: May 2007

Hourly concentrations of airborne sporangia of Peronospora antirrhini at a commercial snapdragon farm were investigated over three growing seasons to determine the influence of the environment on their occurrence and concentration. Hourly concentrations of sporangia of P. antirrhini were estimated using a Burkard volumetric spore sampler. Atmospheric sporangial concentrations followed a diurnal pattern and were greatest during 0500 to 1200 h. Minimum daily temperatures <10.0°C appeared to have a moderate limiting effect on atmospheric sporangial concentrations, whereas temperatures <6.0°C had more severe limiting effects. Maximum daily temperatures ≥30.0°C limited concentrations of atmospheric sporangia. Long dew periods (≥6 h) were associated with relatively large sporangia releases. On 69 days (1999 to 2001), the total number of sporangia trapped was >100/m3/day, and the average length of leaf wetness duration prior to these releases was 11 h. Consecutive days with short leaf wetness periods were associated with low atmospheric sporangial concentrations. Significant positive correlations (P = 0.0502 and P = 0.0174) were found between total rainfall and total spore count for both research plots in 2000. Information gained from this study will contribute to the development of a disease management program that utilizes environmental cues to prompt fungicide applications, thus increasing the efficiency of fungicide programs and delaying the development of pathogen resistance.
Genetic Structure of Botrytis cinerea Populations from Different Host Plants in California
Authors: Ma Zhonghua , Michailides Themis J.
Published: May 2007

The population structure of Botrytis cinerea was investigated by using transposable elements, DNA fingerprinting generated by microsatellite primed-polymerase chain reaction (MP-PCR), and sensitivity to the hydroxyanilide fungicide, fenhexamid, for 234 isolates collected from fig, grape, kiwifruit, pea, and squash in California. Among 234 isolates tested, 195 had two transposable elements, Boty and Flipper (transposa type), 38 had only the Boty element (Boty type), and one had neither of these elements (vacuma type). Four of these 234 isolates, which belonged to the Boty type, were resistant to fenhexamid. A phenogram generated based on MP-PCR markers showed that the isolates were not clustered based on their source hosts or the presence of transposable elements. Analysis of molecular variance (AMOVA) showed that there were no significant genetic differentiations among isolates collected from grape, kiwifruit, pea, and squash at the Kearney Agricultural Center. A more detailed analysis based on AMOVA partition of the total genetic variance indicated that 96% of the variation occurred within populations. The parsimony tree length permutation (PTLPT) and index of association ( IA) analyses of MP-PCR data set were consistent with absence of sexual recombination in sampled populations of this pathogen.
Effect of Benzothiadiazole on Transmission of X-Disease Phytoplasma by the Vector Colladonus montanus to Arabidopsis thaliana, a New Experimental Host Plant
Authors: Bressan Alberto , Purcell Alexander H.
Published: May 2007

Colladonus montanus (Van Duzee), a leafhopper vector of X-disease phytoplasma (Xp), efficiently transmitted the pathogen to Arabidopsis thaliana Columbia wild type. During transmission trials, the phytoplasma was inoculated into 22-, 34-, and 40-day-old plants. Phytoplasma infections were confirmed by polymerase chain reaction (PCR) using primers specific for Xp Symptoms in Xp-positive A. thaliana were overall stunting and reduced or no fruit (silques). All symptom-free plants were PCR negative. Leafhopper nymphs free of Xp that fed on diseased A. thaliana acquired and transmitted Xp to celery plants, a diagnostic host, causing typical X-disease symptoms. Foliar spray applications of the plant resistance elicitor benzothiadiazole (BTH) to A. thaliana 1 week before phytoplasma inoculation significantly reduced phytoplasma infection, ranging from an infection rate of 73.7% for untreated plants to 50 and 35% for plants treated with 1.2 and 4.8 mM BTH, respectively. Vector leafhoppers survival was significantly reduced on BTH-treated A. thaliana compared with leafhoppers on nontreated plants, suggesting that systemic acquired resistance in this plant may have some detrimental effect on the leafhopper C. montanus.
Races of Puccinia graminis Identified in the United States During 2003
Authors: Jin Y.
Published: May 2007

Stem rust of small grain cereals, caused by Puccinia graminis, is a major disease of wheat, barley, and oat. In order to effectively utilize stem rust resistance in the improvement of small grain cereals, it is necessary to monitor the virulence composition and dynamics in the stem rust population. Races of P. graminis from barberry, wheat, barley, and oat were surveyed across the United States during 2003. Aecial infections on barberry were primarily due to P. graminis f. sp. secalis, as inoculations using aeciospores failed to produce infection on wheat and oat. Race QFCS of P. graminis f. sp. tritici was the most common race identified from wheat and barley. Race QFCS has virulence on stem rust resistance genes Sr5, 8a, 9a, 9d, 9g, 10, 17, and 21 that are used for race identification. Race TTTT was identified in 2003. This race possesses virulence to all 16 stem rust resistance genes present in the wheat stem rust differentials and should be targeted in breeding for stem rust resistance. Race QFCN appeared to be a new race in the U.S. stem rust population. Races QCCJ and MCCF were identified, but at low frequencies. Seven races of P. graminis f. sp. avenae were identified from oat, and races NA-27, NA-29, and NA-67 were the predominant races. Race NA-76 was identified for the first time in the United States.
First Report of Meloidogyne partityla on Pecan in Florida
Authors: Crow W. T. , Levin R. , Halsey L. A. , Rich J. R.
Published: May 2007

Pecan (Carya illinoensis (Wagenh.) K. Koch) is an important tree in the southern United States for commercial nut production and residential use. Meloidogyne partityla (pecan root-knot nematode) is only known to parasitize trees in the Juglandaceae including pecan, walnut, and hickory. In the United States, it has been reported on pecan in Texas, New Mexico, and Georgia and internationally in South Africa. Portions of a large pecan nursery in Madison County, Florida were infested with an unknown species of root-knot nematode. The pecan trees at this nursery are grafted onto rootstock and grown in the field until the trees are large enough to sell as bare-root transplant stock in several states including and adjoining Florida. Trees infected by the root-knot nematodes were stunted, had extensive galling and rotting of the root system, and pulled from the ground relatively easily compared with noninfected trees. Attempts to rear these nematodes on tomato in the greenhouse were unsuccessful. Young egg-laying females were isolated directly from pecan roots for speciation. Enzymes extracted from females were resolved with polyacrylamide gel electrophoresis [4% stacking (pH 6.8) and 8% separating gel (pH 8.8) with Tris-glycine buffer]. The esterase (Est) and malate dehydrogenase (Mdh) phenotypes of the unknown Meloidogyne sp. were consistent with those reported for M. partityla. In addition, specimens of M. partityla maintained by the USDA Southeastern Fruit and Tree Nut Research Laboratory in Byron, GA were obtained and their Est and Mdh phenotypes compared with the unknown Meloidogyne sp. under identical electrophoretic and enzyme staining protocols. The Est and Mdh phenotypes of the two isolates were identical. Therefore, we conclude that the root-knot nematodes infesting the pecan nursery in Florida are M. partityla. To our knowledge, this is the first report of this nematode in Florida and also the first report of this nematode from infected nursery stock. It is unknown how long the field has been infested but clearly, there is potential for spread of M. partityla to locations around Florida and bordering states. This nematode may be widespread throughout pecan-growing regions of the United States.

References: (1) K. P. N. Kleynhans. Phytophylactica 18:103, 1986. (2) A. P. Nyczepir et al. Plant Dis. 86:441, 2002. (3) J. L. Starr et al. J. Nematol. 28:565, 1996. (4) S. H. Thomas et al. Plant Dis. 85:1030, 2001.
First Report of the Rust Fungus Coleosporium tussilaginis on Tussilago farfara in Turkey
Authors: Tunali B. , Yildirim A. , Aime M. C. , Hernández J. , Berner D.
Published: May 2007

Tussilago farfara L. (“coltsfoot”, Asteraceae) is indigenous to Eurasia, including Turkey, but has been classified as a Class A noxious weed in North America. Plant pathogens are being sought as potential candidates for biological control of coltsfoot. A rust fungus, Coleosporium tussilaginis (Pers) Lev. has been reported to cause disease on T. farfara from Europe, Russia, and Japan (2). During August of 2001 and 2002, rust pustules were observed on coltsfoot leaves in Kizilcahamam, Ankara, Turkey. Diseased plant specimens with rust pustules were collected, examined microscopically, and compared with published descriptions (1) and specimens in the U.S. National Fungus Collections in Beltsville, MD. The causal agent was subsequently identified as the fungus Coleosporium tussilaginis (Pers.) Lév. on the basis of symptomatology and morphology of uredinial and telial stages such as: clustered, golden-orange, sub-epidermal, erumpent, uredinia approximately 1.0 × 2.0 mm in diameter on the abaxial surface, and corresponding achlorotic areas on the adaxial leaf surfaces; thick-walled (3.0 to 4.0 μm), pale orange, coarsely verrucose, variously shaped (mostly broadly ellipsoid or angular) urediniospores measuring 23.5 to 33.0 × 20.0 to 25.7 μm (average = 27.3 × 23.3 μm), with obscure and scattered germ pores; and orange-red telia on the abaxial leaf surfaces covered by a gelatinous apical layer enclosing orange-red, cylindrical to clavate teliospores measuring 50.0 to 80.0 × 18.0 to 28.0 μm. A voucher specimen of this material has been deposited in the U.S. National Fungus Collections (BPI 863516). To the best of our knowledge, this is the first report of C. tussilaginis rust on coltsfoot in Turkey.

References: (1) G. Deml et al. Phytopathol. Z 104:39, 1982. (2) D. F. Farr et al. Fungal Databases. USDA-ARS Systematic Botany and Mycology Laboratory, Online publication. ARS, USDA, 2005.
Development of a DNA Macroarray for Detection and Monitoring of Economically Important Apple Diseases
Authors: Sholberg Peter , O'Gorman Dan , Bedford Karen , Lévesque C. André
Published: May 2007

Short DNA gene sequences (oligonucleotides) from the ribosomal spacer regions of bacterial and fungal pathogens were used to identify and monitor economically important apple diseases. The oligonucleotides or probes were attached to a nylon membrane by an amine modified linker arm and arranged in a precise pattern to form an array for detecting five pathogens corresponding to five apple diseases. Initially the specificity of the probes was determined by hybridizing pure cultures of the pathogens to the probes. The DNA array correctly identified Botrytis cinerea, Penicillium expansum, Podosphaera leucotricha, Venturia inaequalis, and Erwinia amylovora and eliminated closely related species. When the array was used to monitor V. inaequalis ascospores collected from spore traps located in orchards, it confirmed the presence of ascospores as predicted by the disease forecasting model. Preliminary tests to quantify P. leucotricha populations using grayscale values was effective to 20 conidia per leaf disk. The DNA array is a promising new detection system for accurate identification of several pathogens in a single test with the potential for being a new tool for epidemiological studies.
First Report of Pink Disease on Native Trees in South Africa and Phylogenetic Placement of Erythricium salmonicolor in the Homobasidiomycetes
Authors: Roux J. , Coetzee M. P. A.
Published: May 2007

Erythricium salmonicolor causes a canker and die-back disease, commonly known as pink disease, on many tree species. During an investigation of diseases of Podocarpus henkellii and P. latifolius in the Mpumalanga Province of South Africa, typical symptoms of pink disease were observed on the branches of these trees. Stem and branch cankers covered with cracked bark and abundant pink mycelial growth were common on the affected trees. In subsequent surveys, the disease was also found on native Dais cotonifolia in the same area, as well as on native Ekebergia capensis and Maesa lanceolata in the KwaZulu-Natal Midlands. Phylogenetic analyses of ribosomal large subunit DNA sequence data were used to confirm the identity of the pathogen and obtain an indication of its phylogenetic placement within the Homobasidiomycetes. Isolates from all the native hosts recorded in this study, as well as from exotic Eucalyptus sp. and Acacia mearnsii, formed a strongly supported clade together with isolates from other parts of the world. Results confirmed that the pathogen in South Africa is Erythricium salmonicolor. Isolates from South Africa and Ethiopia grouped closely together, slightly different from E. salmonicolor isolates from the rest of the world. Our data also suggest that the genus name for E. salmonicolor possibly should be reconsidered because it groups separately from E. laetum or Corticium roseum. Phylogenetic analyses further indicated that the genus Erythricium is most closely related to Marchandiomyces aurantiacus, M. lignicola, C. roseum, E. laetum, Dendrothele maculata, D. roseacarneum, Vuilleminia comedens, V. macrospora, Punctularia strigoso-zonata and Galzinia incrustans. These genera form a separate subclade, the corticioid clade, within the Homobasidiomycetes. Pink disease is potentially important in South Africa because it affects a wide range of native and exotic tree species, and this study provides a foundation for further research.
High-Speed Optical Sorting of Soft Wheat for Reduction of Deoxynivalenol
Authors: Delwiche Stephen R. , Pearson Thomas C. , Brabec Daniel L.
Published: May 2007

Fusarium head blight (FHB) is a fungal disease that affects small cereal grains, such as wheat and barley, and is becoming more prevalent throughout much of the world's temperate climates. The disease poses a health risk to humans and livestock because of the associated production of the mycotoxin deoxynivalenol (DON or vomitoxin) by the causal organism, Fusarium graminearum. A study was undertaken to examine the efficiency of high-speed, optical sorting of intact wheat (Triticum aestivum) kernels for reduction of DON concentration. Soft red winter (n = 32) and soft white (n = 3) wheat samples, known to have elevated levels of FHB, were obtained from commercial mills throughout the eastern United States. An additional seven samples of wheat from the discard piles of in-mill cleaners were also studied. Fusarium-damaged wheat, cleaned of nonkernels and foreign material ( ~4.5 kg/sample, DON range = 0.6 to 20 mg/kg), was fed into a commercial high-speed bichromatic sorter operating at a throughput of 0.33 kg/(channel-min) and a kernel rejection rate of 10%. A wavelength filter pair combination of 675 and 1,480 nm was selected for sorting, based on prior research. Visual measurements of the proportion of Fusarium-damaged kernels were collected on incoming and sorted seed (separate analyses of accepted and rejected portions), as were measurements of DON concentration. Results indicated that the fraction of DON contaminant level in the sorted wheat to that in the unsorted wheat ranged from 18 to 112%, with an average of 51%. Nine of the 35 regular samples and all seven of the discard pile samples underwent a second sort, with five from this second set undergoing a third sort. Multiple sorting was effective in producing wheat whose DON concentration was between 16 and 69% of its original, unsorted value.
Phytophthora ramorum on Quercus ilex in the United Kingdom
Authors: Denman S. , Kirk S. A. , Brasier C. M. , Barton V. C. , Hughes K. J. D. , Webber J. F.
Published: May 2007

Phytophthora ramorum causes bleeding cankers of trunks of trees native to the west coast of the United States (i.e., Quercus kelloggii, Q. parvula var. shrevei, and Lithocarpus densiflorus). In the United Kingdom so far, bleeding cankers caused by inner bark infections have been found on Aesculus hippocastanum, Fagus sylvatica, Q. cerris, Q. falcata, and Q. petraea ( http://rapra.csl.gov.uk [2005]). Shoot tip dieback (ramorum dieback) and foliar necrosis (ramorum leaf blight) are other diseases caused by the pathogen on understory and ornamental plants (3). Inoculum is produced on infected shoots and leaves of foliar hosts but not on bole cankers (1). Foliar hosts are thus critical in initiating and maintaining epidemics of tree mortality resulting from lethal bark cankers. Ramorum dieback and blight occurs in Europe on genera Rhododendron, Camellia, Kalmia, Pieris, and Viburnum (http://rapra.csl.gov.uk [2005]), and now we report these diseases on foliage and shoots of holm oaks (Quercus ilex) in Cornwall (UK). First discovered in November 2003, infected young leaves had a water-soaked, dull gray appearance, and petioles were blackened. Lesions started at leaf margins, tips, or petioles, often progressing into the midrib veins. Initial infections also occurred on shoots and extended into the petioles. If shoots were infected, they were blackened at first, but later in the season clusters of dry, dead leaves and twigs characterized branch tips. Infected mature leaves bore dry, reddish-brown, restricted lesions. P. ramorum (A1 sexual compatibility type belonging to the European population) was isolated and confirmed by morphological studies, ITS sequence (GenBank Accession No. AY924253), and amplified fragment length polymorphism analyses. Lesions developed on detached leaves dipped for 10 sec in inoculum (4 × 105 zoospores per ml) and incubated in moist chambers at 20°C for 6 days (2). Two isolates were used (four leaves per isolate). The pathogen was reisolated, and the tests were repeated twice. Koch's postulates were also successfully completed once on foliage attached to saplings. To our knowledge, this is the first report of P. ramorum on holm oak. So far, at least 24 holm oaks are infected at various woodland and garden sites in the United Kingdom; infected rhododendrons have also been found at these sites. P. ramorum has also been recorded on saplings in nurseries. The high sporulation potential, the evergreen nature of leaves, and susceptible shoots indicate that holm oak could be a significant source of inoculum for other hosts.

References: (1) J. M. Davidson et al. Phytopathology 95:587, 2005. (2) S. Denman et al. Plant Pathol. 54:512, 2005. (3) E. M. Hansen et al. Plant Dis. 89:63, 2005.
Iris yellow spot virus: A New Onion Disease in Spain
Authors: Córdoba-Sellés C. , Martínez-Priego L. , Muńoz-Gómez R. , Jordá-Gutiérrez C.
Published: May 2007

So far, only three viral diseases have been identified in onion crops grown in Spain. These are Tomato spotted wilt virus (TSWV), Onion yellow dwarf virus (OYDV), and Leek yellow stripe virus (LYSV). In September 2003, unusual virus-like symptoms including straw-colored, dry, tan, diamond-shaped lesions on the leaves and stalks, sometimes with necrotic lesions, curled leaves, and bulbs of reduced size, were observed on several onion plants (Allium cepa L.) in commercial fields in Albacete, Spain. Severely affected plants eventually died. To verify the identity of the disease found in the Spanish onions, double-antibody sandwich enzyme-linked immunosorbent assay (DAS-ELISA) was performed on leaf extracts of symptomatic onions using specific polyclonal antibodies against OYDV, LYSV, Cucumber mosaic virus (CMV) (Biorad Phyto-Diagnostics, Marnes-La Coquette, France), Iris yellow spot virus (IYSV), and TSWV (Loewe Biochemica, Sauerlach, Germany). All samples of infected onion tissue were positive for IYSV and negative for the other viruses tested. To confirm the ELISA results, viral RNA was extracted from five of the ELISA-positive onion samples, a healthy onion plant, and a positive control for IYSV (DSMZ, Braunschweig. Germany). The extracted RNA was used in a One-Step reverse transcription-polymerase chain reaction (RT-PCR) assay using SuperScript Platinum Taq (Invitrogen Life Technologies, Barcelona, Spain) in the presence of the IYSV1S and IYSV1A primers for the nucleocapsid gene of IYSV (1). The RT-PCR assay produced an amplicon of the expected size of 790 bp. No amplification products were observed when healthy plants or a water control were used as templates in the RT-PCR reaction. To establish the authenticity of the virus from onion, the PCR products were purified (High Pure PCR Product Purification Kit, Roche Diagnostics, Mannheim, Germany), sequenced, and the nucleotide sequences obtained were analyzed and compared with the published sequences in GenBank. The PCR product was 97% identical to the sequence of the IYSV nucleocapsid gene (Genbank Accession No. AB121026). IYSV, an emerging tospovirus that is potentially a devastating pathogen of onion, has been reported in many locations in Brazil, Japan, the Netherlands, Israel, Australia, the western United States, Slovenia, and Iran (2). IYSV is included in the European and Mediterranean Plant Protection Organization alert list of viruses (2), and to our knowledge, this is the first report of IYSV in Spain. This tospovirus is transmitted in a propagative manner by Thrips tabaci. Although the vector is present in large populations in the onion-growing areas in Spain, the efficiency of the Mediterranean ecotype in transmitting IYSV is not known.

References: (1) B. A. Coutts et al. Australas. Plant Pathol. 32:555, 2003. (2) European and Mediterranean Plant Protection Organization. EPPO on-line publication at www.eppo.org/QUARANTINE/Alert_List/Viruses/irysxx.html .
First Report of Tomato chlorosis virus and Tomato infectious chlorosis virus in Tomato Crops in France
Authors: Dalmon A. , Bouyer S. , Cailly M. , Girard M. , Lecoq H. , Desbiez C. , Jacquemond M.
Published: May 2007

Since 2002, yellowing symptoms associated with high levels of white-fly populations have been observed in plants of protected tomato crops in France. Symptomatic plants exhibited interveinal yellowing areas in older leaves, followed by generalized yellowing. Symptoms were not observed in young plants or fruits. Trialeurodes vaporariorum populations were generally abundant in spring, and Bemisia tabaci (established in France for approximately 10 years) became predominant in summer and fall. To check for the presence of Tomato chlorosis virus (ToCV) and Tomato infectious chlorosis virus (TICV), two whitefly-transmitted criniviruses known to induce yellowing symptoms, 696 samples were collected in the major tomato-growing areas; 573 samples from southern France and 123 samples from northern France. Total RNA was extracted from each sample and analyzed using reverse transcription-polymerase chain reaction (RT-PCR). Primers specific to ToCV (2) and TICV (1,3) were used to amplify either part of the heat-shock-like protein gene HSP70h (both viruses) or part of the diverged coat protein gene (CPd), (TICV only). A 439-bp DNA fragment was obtained with ToCV primers in 178 samples from southern France collected mainly from mid-spring to early fall from 2002 to 2004. Three RT-PCR products amplified from samples collected from diverse growing areas were sequenced and showed 99 to 100% sequence identity with published ToCV sequences from Spain (GenBank Accession Nos. AF215818, AF233435, and AF215817), Portugal (GenBank Accession No. AF234029), Sicily (GenBank Accession No. AY048854), and the United States (GenBank Accession No. AF024630). Considering the high frequency of ToCV-infected samples (41 positive samples of 112 samples collected in 2002, 71 of 295 collected in 2003, and 66 of 166 collected in 2004), this virus appears to be well established in southern France but remains absent in the northern regions. The presence of TICV was tested in 485 samples using the CPd-specific primers or the HSP70h-specific primers. The virus was detected in only two samples from Nice (southeastern France) in 2003 with both primer pairs. The CPd DNA fragment (700 bp) from one of these samples was sequenced, showing 98.9% sequence identity with a TICV Japanese isolate (AB085603). Results of these assays suggest that in contrast to ToCV, TICV is not yet broadly established in France. This difference could be associated with the specificity of the vectors, since ToCV is transmitted by B. tabaci and T. vaporariorum, while TICV is transmitted only by T. vaporariorum (4).

References: (1) R. H. Li et al. Plant Dis. 82:84, 1998. (2) D. Louro et al. Eur. J. Plant Pathol. 1065:589, 2000. (3) A. M. Vaira et al. Phytoparasitica 30:290, 2002. (4) G. C. Wisler et al. Plant Dis. 82:271, 1998.
Quantitative Assessment ofAnguinasp. andRathayibacter rathayiinDactylis glomerataSeed Production Fields in Oregon and Estimates of Yield Loss
Authors: Alderman Steve C. , Ocamb Cynthia M. , Mellbye Mark E.
Published: May 2007

Anguina sp. is a nematode that infests the inflorescence of orchardgrass and forms galls that replace the seed. Anguina sp. is also a vector of the bacterial pathogen Rathayibacter rathayi, which causes galls or gummosis in orchardgrass (Dactylis glomerata) panicles. The percentage of orchardgrass panicles infected or percentage of seed loss from Anguina sp. or R. rathayi in five commercial orchardgrass seed-production fields in Oregon during 2003 and 2004 was determined. The percentage of panicles with Anguina sp. ranged from 9 to 24%, although the percentage of seed replaced by Anguina sp. was less than 0.2%. The number of galls per panicle ranged from 1 to 29. However, more than 50% of Anguina-infested panicles contained only a single Anguina gall and few panicles had eight or more galls. The percentage of panicles with R. rathayi ranged from 3 to 27%. Percentage of seed loss from R. rathayi ranged from 0.1 to 7.3%. Seed loss in orchardgrass seed-production fields assessed for both Anguina sp. and R. rathayi was found to be as great as 8%. The number of Anguinagalls remaining in fields following harvest ranged from 0 to 40 per square meter
First Report of Apple Rot Caused by Neofabraea alba in Chile
Authors: Henriquez J. L.
Published: May 2007

A new rot of stored apples was observed in local and export markets on apples that were grown in the south-central region of Chile during 2004. Circular, pale brown spots with a darker outer ring were observed at least 3 months after harvest in cvs. Braeburn, Fuji, Granny Smith, Pink Lady, and Royal Gala. Lesions developed from lenticel cavities or wounds and reached 2 to 3 cm in diameter after 1 week at room temperature. Symptoms resembled those produced by the bull's eye rot pathogens on apple that occur in other parts of the world. Acervuli developed in the rotted areas, and microscopic examination revealed the presence of the fungus Neofabraea alba (Guthrie) (anamorph Phlyctema vagabunda Desm.) characterized by production of curved macroconidia and absence of microconidia (1). Pure culture on potato dextrose agar (PDA) yielded a characteristic white sterile mycelium. Four cv. Pink Lady apples were wound inoculated with mycelium of the pathogen and four apples were wound inoculated with a 5 × 104 CFU/ml conidial suspension. Four apples were wounded and inoculated with sterile water as a negative control. The fruit was held at 20°C. Symptoms appeared after 4 and 5 days in the mycelium and conidial inoculated apples, respectively. Resulting symptoms were similar to those originally observed. Abundant macroconidia were produced at the inoculation sites, and a sterile, white mycelium was recovered after isolation on PDA. To our knowledge, this is the first report of apple fruit rot caused by N. alba in Chile.

Reference: (1) J. L. Henriquez et al. Plant Dis. 88:1134, 2004.
First Report of Formosan Michelia Seedling Root Rot Caused by Pythium splendens in Taiwan
Authors: Fu C. H. , Chen C. M. , Hsieh H. J.
Published: May 2007

Formosan michelia (Michelia compressa (Maxim.) Sargent) is a valuable evergreen tree in Taiwan that is distributed from low to medium (200 to 1,800 m) altitudes. In many nurseries in Taiwan, Formosan michelia seedlings grow poorly or wilt. The etiology of the disease observed in April 2004 in a nursery in Jinshan was investigated. Diseased seedlings with chlorotic leaves and decayed feeder roots lost leaves, died back, and then wilted. The putative pathogen, Pythium splendens Braun, was isolated and identified on a morphological basis (1). P. splendens was isolated from the roots of diseased seedlings on 2% water agar with 100 ppm of ampicillin. Isolates increased daily on potato dextrose agar at 24°C by 27 to 30 mm and on malt extract agar (MEA) by 23 to 25 mm. No zoosporangia and zoospores were produced. The main hyphae were as much as 9 μm wide on MEA. Hyphal swellings were abundant, globose, smooth, terminal, and 33 to 42 μm in diameter, often with dark, densely granulated contents. Attempted matings of four P. splendens isolates in V8 medium failed. To prove pathogenicity, the four isolates were cultured in 300-ml flasks containing 150 ml of 2% malt extract medium at room temperature for 14 days. The mycelia were homogenized in sterile water at 4,500 rpm for 5 min. The suspension was adjusted to 5 × 106 hyphal swellings per ml. Roots of the 2-month-old seedlings were immersed in the suspension for 2 h, whereas the control seedlings were immersed in sterilized water. Five seedlings of each of three replicates were inoculated with one of the four isolates for a total of 60 seedlings. Controls were replicated in the same way. The inoculated plants were transplanted into plastic flowerpots containing sterilized peat and moss and kept in the greenhouse at 20 to 24°C. After 14 days, inoculated seedlings developed symptoms like those of the original plants. The putative pathogen was reisolated from the roots of inoculated plants. Cultures are maintained at the Forest Pathology Lab of the National Taiwan University. To our knowledge, this is the first report of proof of pathogenicity of P. splendens on Formosan michelia seedlings.

Reference: (1) A. J. Van der Plaats-Niterink. Stud. Mycol. 21:151, 1981.
First Report of Cherry green ring mottle virus on Sweet Cherry in Poland
Authors: Komorowska B. , Cieślińska M.
Published: May 2007

Cherry green ring mottle virus (CGRMV), a member of the genus Foveavirus, infects several Prunus species including sweet cherry, sour cherry, ornamental cherry, peach, and apricot throughout North America and Europe. On sour cherry, the virus causes leaf yellowing and dark mottle around secondary veins. Sweet cherry trees are symptomless hosts of CGRMV. During the 2004 growing season, 27 sour and sweet cherry trees were tested for the presence of CGRMV. RNA was isolated from leaves using an RNeasy kit (Qiagen GmbH, Hilden, Germany) and then evaluated by reverse transcription-polymerase chain reaction (RT-PCR) amplification. Two primer sets, GRMV7956/GRMV8316 (1) and NCP5/NCP3 (2), were used for amplification of the CGRMV coat protein gene (807 bp) or its fragment (366 bp), respectively. The cDNA fragments were cloned into bacterial vector pCR 2.1-TOPO, sequenced and analyzed using the Lasergene (DNASTAR, Madison, WI) computer program. Nucleotide sequence of the C328 isolate (GenBank Accession No. AY841279) was compared with corresponding regions of published sequences of CGRMV isolates. The nucleotide sequence of this isolate was 98% identical to the Leb isolate (GenBank Accession No. AF533157) from sour cherry. The lowest similarity (80%) was between the CP sequences of isolate C328 and an isolate from apricot (GenBank Accession No. AY172334.1). Results of biological indexing on Prunus serrulata ‘Shirofugen’ and ‘Kwanzan’ confirmed the infection of ‘Star’ sweet cherry with CGRMV. The indicators showed leaf epinasty and necrosis of fragments of midrib or veins characteristic for CGRMV (2). The CGRMV infection of the indicators was confirmed using RT-PCR.

References: (1) M. E. Rott and W. Jelkmann. Eur. J. Plant Pathol. 107:411, 2001. (2) Y. Zhang et al. J. Gen. Virol. 79:2275, 1998.
First Report of Phytophthora cactorum Causing Fruit Rot on Avocado in Spain
Authors: López-Herrera C. J. , Pérez-Jiménez R. M. , Zea-Bonilla T.
Published: May 2007

The area of avocado (Persea americana Mill.) orchards in southern Spain has increased recently and is currently at 8,063 ha. Avocado production in this part of Spain was 72,581 t during 2003. During February 2004, apical necrosis was observed on avocado fruits (cv. Hass) in one orchard in Vélez-Málaga, Málaga Province, southern Spain. Dark brown lesions and necrotic flecking of the flesh also were observed on fruits. Isolations from the skin of the fruit previously washed with tap water and disinfested with 20% sodium hypochlorite on potato dextrose agar (PDA) consistently resulted in mycelial colonies. Sporangia produced on V8 juice by successive washing of mycelia with saline solution (1) measured 31 to 37.2 (33.3) × 21.7 to 28.8 (24.2) μm in size. The pathogen was identified as Phytophthora cactorum on the basis of morphological structures (mycelia, sporangia, chlamydospores, and oospores) formed when grown on V8 juice and PDA (2). To confirm pathogenicity, a mycelial suspension was obtained by blending mycelia grown for 1 week on PDA in 200 ml of sterile water. Three healthy avocado fruits were inoculated with the suspension by injection; three other fruits were inoculated by placing a drop of suspension on the unbroken skin of the fruit. The same number of fruit was inoculated as controls using sterile water instead of mycelial suspension. The inoculated fruits were incubated for 5 days in a moist chamber at 24°C in darkness. Spots appeared on all fruits for both inoculation methods, and the pathogen was isolated and identified as P. cactorum. No symptoms appeared on the control fruits. To our knowledge, this is the first report of P. cactorum causing fruit rot on avocado in Spain.

References: (1) D. Chen and G. A. Zentmeyer. Mycologia 62:397, 1970. (2) G. M. Waterhouse and J. M. Waterston. No. 111 in: Descriptions of Pathogenic Fungi and Bacteria. CMI, Kew, Surrey, UK, 1966.
Comparison of Severity Assessment Methods for Predicting Yield Loss to Rhizoctonia Foliar Blight in Soybean
Authors: Stetina K. C. , Stetina S. R. , Russin J. S.
Published: May 2007

Rhizoctonia foliar blight, caused by Rhizoctonia solani Kühn anastomosis group 1, causes rapid and severe destruction of soybean foliage and pods during hot, wet weather. The objectives of this study were to determine the yield components affected by this disease and whether rating pod damage or foliar damage provides a more reliable method of assessing disease severity relative to impact on yield. Disease severity in the moderately resistant cv. NK S57-11 and the susceptible cv. Buckshot 723 was assessed in field plots in 1996 and 1997 using foliar and pod ratings (0-to-10 scale corresponding to 0 to 100% of tissue affected). Based on results from regression analysis, pod number, seed number, and seed weight per plot decreased as disease severity increased, whereas the proportion of partially filled pods and the weight of 100 seed were not affected. Yield loss appeared to be due primarily to loss of entire pods. Foliar and pod assessments of disease severity correlated positively in 1996 (r = 0.8343) and 1997 (r = 0.5958) for both cultivars, which suggests that either method can be used to identify relative differences among cultivars. However, pod assessments accounted for more variability than foliar assessments under low-disease conditions. Plants exhibiting moderate to severe symptoms of Rhizoctonia foliar blight also retained green stems and pods at harvest, which was evidence of delayed maturity.
A Begomovirus Associated with Leaf Curling and Chlorosis of Soybean in Sinaloa, Mexico is Related to Pepper golden mosaic virus
Authors: Méndez-Lozano J. , Quintero-Zamora E. , Barbosa-Jasso M. P. , Leyva-López N. E. , Garzón-Tiznado J. A. , Argüello-Astorga G. R.
Published: May 2007

Since June 2001, symptoms of yellowing, leaf curling, crumpling, and stunted growth were observed on soybean (Glycine max Merr.) plants in Sinaloa, Mexico. These symptoms and the presence of whiteflies (Bemisia tabaci Gennadius) in the affected fields suggested a viral etiology. Samples from symptomatic plants were collected from commercial fields and analyzed for the presence of begomoviruses using DNA hybridization, and as a probe, the DNA A of Pepper huasteco virus at low stringency (2). Thirty-five positive samples were subsequently used for polymerase chain reaction (PCR) amplification with the degenerate primers RepMot and CPMot (1). These primers direct the amplification of a DNA A segment comprising the entire intergenic region (IR) and the first 210 bp of the coat protein (CP) gene, which is highly variable in size and nucleotide sequence among begomoviruses. PCR products were obtained for 25 of 35 samples and five of these were cloned into the pGEM-T easy vector (Promega, Madison, WI) and sequenced. The 571-bp DNA sequence (GenBank Accession No. AY905553) was compared with sequences of other begomoviruses in GenBank using the Clustal alignment method (MegAlign, DNASTAR software, London). The sequence was 74 and 70% identical to the Pepper golden mosaic virus (PepGMV; GenBank Accession No. U57457) and Cabbage leaf curl virus (CaLCuV; GenBank Accession No. U65529) sequences, respectively. Interestingly, the partial coat protein gene sequence (210 nt) of this soybean-infecting virus was 98% identical to the CP gene of Tobacco apical stunt virus (TbASV; GenBank Accession No. AF076855). Nonetheless, the known sequence of TbASV intergenic region (GenBank Accession No. AF077744) is very different from the homologous region of the soybean virus (34% of nucleotide identity). Analysis of the soybean virus intergenic region revealed that it harbors almost identical iterons (i.e., Rep-binding sites) to PepGMV, suggesting a close relationship between these two viruses. Soybean-infecting geminiviruses have been previously reported only from Asia; however, the partial sequence of a begomovirus isolated from soybean in Brazil was recently deposited in Genbank (Accession No. AY436328). Sequence comparisons between the Brazilian and Mexican isolates showed these viruses are less related with a nucleotide identity of 46%. Taken together, our data indicate that the virus identified in this study might be either a different strain of PepGMV adapted to leguminous plants or a new begomovirus species. To our knowledge, this is the first report of a begomovirus infecting soybean in Mexico.

References: (1) J. T. Ascencio-Ibañez et al. Plant Dis. 86:692, 2002. (2) J. Méndez-Lozano et al. Phytopathology 93:270, 2003.
First Report in Sweden of Downy Mildew on Parsley Caused by Plasmopara petroselini
Authors: Amein T. , Olsson C. H. B. , Wikström M. , Findus R , AB D , Wright S. A. I.
Published: May 2007

During September 2004, downy mildew of parsley caused by a species of Plasmopara was observed in an experimental field of parsley (Petroselinum crispum subsp. crispum L. cv. Gigante d'Italia/Hilmar) in Borgeby in southern Sweden. The summer of 2004 was exceptionally wet and humid. Disease became widespread throughout the field in just a few days. Local growers reported that symptoms consistent with downy mildew had appeared in their parsley fields every year since 2001. Plasmopara, under P. nivea, has been reported on parsley in Europe since the middle of the 19th century (4). In recent years, this disease has caused severe damage to parsley grown in several European countries, e.g., France, Germany, Switzerland, and Belgium (1,3). The first symptoms appeared as faint chlorotic spots on the upper surfaces of the leaves. On the corresponding lower surfaces, mycelium and sporangiophores grew profusely and developed a white mat that in part turned dark gray. Eventually, the leaves and stalks became necrotic and died. The sporangiophores were monopodially branched, 248.4 ± 13.36 μm long (n = 17), each branch ending in 2 to 5 ultimate branchlets tapered toward the tip. The trunk diameter measured 7.0 ± 0.77 μm (n = 9) above the basal part and 6.1 ± 0.81 μm just below the first branch. The sporangia were broadly ellipsoidal to ellipsoidal, hyaline, 22.5 ± 0.73 μm long and 16.6 ± 0.48 μm wide (n μ 40). They were mostly nonpapillate when young, although exit pores 4.8 ± 0.32 μm (n = 10) were visible. Mature sporangia exhibited a dehiscence apparatus and a plug in the exit pore. On the basis of the characteristics above, the pathogen was identified as P. petroselini (= P. nivea pro parte [2]). Independent verification of the identity was done by O. Constantinescu at the Botanical Museum, Uppsala, Sweden. A voucher specimen was deposited at the Herbarium UPS, in Uppsala under the number UPS F-118873. To our knowledge, this is the first report of P. petroselini on parsley in Sweden.

References: (1) E. Bèliard and J. Thibault. Phytoma 554:2, 2002. (2) O. Constantinescu. Taxon 54:813, 2005. (3) C. Crepel and S. Inghelbrecht. Plant Dis. 87:1266, 2003. (4) A. de Bary, Ann. Sci. Nat. Bot., Sér. 4, 20:5, 1863.
Genetic Diversity Among Ophiosphaerella agrostis Strains Causing Dead Spot in Creeping Bentgrass
Authors: Kaminski John E. , Dernoeden Peter H. , Mischke Sue , O'Neill Nichole R.
Published: May 2007

Dead spot (Ophiosphaerella agrostis) is a relatively new disease of young creeping bentgrass and hybrid bermudagrass putting greens in the United States. Little is known about the biology or genetic diversity of the pathogen. O. agrostis is unusual in that it produces prodigious numbers of pseudothecia in the field throughout the summer months and has no known asexual state. A total of 77 O. agrostis isolates were collected from 21 different bentgrass putting greens and one hybrid bermudagrass green in 11 states. DNA fingerprint analysis revealed that 78 out of 97 markers were polymorphic (80.4%), providing 57 unique profiles. Genetic variation of O. agrostis was diverse, and isolates separated into three distinct clades with ≥69% similarity. Analysis of molecular variance indicated that the geographic origins of the isolates and the ability to produce pseudothecia were the best indicators for genetic similarity among O. agrostis isolates. Colony color varied among the isolates, but generally was similar for isolates residing within two clades (B and C). Colony color of isolates within clade A appeared to be a mixture of the colony colors exhibited by clades B and C. Isolates examined within each clade generally had varying levels of pseudothecia production and varying colony colors when grown on PDA. Although O. agrostis is a homothallic species, it is unclear if outcrossing among strains occurs.