A new disease causing wilt and death of adult plants of Phaseolus vulgaris was discovered in plastic-house crops of southeast Spain in 2004. The causal agent was shown to be a Pythium species with a unique type of oogonium ornamentation different from any of the described species. Zoospores were not observed, but globose or subglobose hyphal swellings, intercalary or terminal, were frequently found. Moreover, the ribosomal ITS region showed a unique sequence, significantly different (>14%) from any other known species of Pythium. This paper describes and illustrates the morphology of the new Pythium species and its pathogenicity to green beans. Its taxonomic position and phylogenetic relationships with other Pythium species are discussed.

Leaf and crown wart, marbled or beet root tumour are some of the common names given to a disease of sugar beet (Beta vulgaris) caused by Urophlyctis leproides (formerly Physoderma leproides). It was first reported in Algeria in 1894 (Trabut, 1894). Since then, the disease has been recorded in Argentina, Italy, Spain, United Kingdom, Palestine and the USA (Whitney, 1971). In Egypt, the disease was observed during harvest (2003, 2004, 2005) at three locations in the Nile Delta (Behira, Gharbia and Kafr El-Sheikh) on a range of sugar beet cultivars (Gloria, Kawmera, Oscar poly, Othus poly and Pleno). Disease incidence (DI) was less than 1% in 2003, 1–2% in 2004 and 3% in 2005. Although the DI is currently low, if the trend observed over the last few years continues, the disease could reach epidemic levels in the near future. The disease exhibited typical symptoms on root crowns and occasionally on petioles and leaf blades. Galls on leaf blades and petioles are greenish brown and have a rough appearance. Affected leaves are malformed. On the crown, galls range in size from 1 cm to (most commonly) 8–10 cm. These galls are spherical, rough and are attached to the host by a narrow base. Gall colour was variable, ranging from shades of green through yellow to brown depending on the age of plant cultivar. Galls occurred singly or coalesced to form complexes. Sections made through a crown gall revealed cavities filled with thick-walled sporangia (resting spores) surrounded by thickened wall. Sporangia were light brown, spherical to ovoid or concave (25 ± 5 × 40 ± 5 µm) in diameter (Ruppel, 1995). As the gall decomposes, resting sporangia are released into the soil. Soil surveys were carried out in the affected areas and detected resting sporangia. Twenty seedlings of B. vulgaris cv. Gloria were inoculated with 105 resting spores mL−1 and incubated 22 ± 2°C in continuous fluorescent light for 48 h, followed by 14 h light and 10 h dark. Uninoculated plants were used as a control. Symptoms appeared on the test plants after 11 days and sporangia were reisolated from the mature gall tissues (Mahmoody et al., 1997). No symptoms were observed on uninoculated controls. This is the first report of sugar beet crown wart disease (U. leproides) affecting B. vulgaris in Egypt. The authors would like to thank Dr El-Sayed Belal for his valuable opinion and Mr Fath for his technical assistance.

La aparicion de una nueva cepa de Tomato Spotted Wilt Virus (TSWV) que supera la resistencia de pimientos, conferida por el gen dominante Tsw, ha sido una causa de la utilizacion de productos fitosanitarios ilegales para controlar el vector. Se ha estudiado la incidencia de la nueva cepa RB-TSWV (supera la resistencia en pimiento) respecto a la cepa hasta ahora habitual de Almeria (wilt type, WT-TSWV que no supera la resistencia en pimiento). Paralelamente se han realizado estudios de caracterizacion biologica y genetica de aislados virales. Los datos indican que la nueva cepa esta muy extendida en el campo almeriense, puesto que de todos los aislados virales ensayados, el 93,3% corresponde con la cepa RB-TSWV y el 6,7% se comporta como la cepa WT-TSWV . Los estudios biologicos de inoculacion en una gama de huespedes y geneticos realizados a varios aislados no muestran diferencias significativas entre ellos, no pudiendo establecerse otra forma de distinguir las cepas salvo la realizacion de bioensayos sobre pimientos sensibles y resistentes.

Cucurbit yellow stunting disorder virus (CYSDV) has been present in greenhouse‐grown cucumber in Spain since 1992. However, in the autumn of 2000 Cucumber vein yellowing virus (CVYV) was introduced, leading to mixed infections of both Bemisia tabaci‐transmitted viruses. The temporal and spatial spread of disease symptoms were monitored in experimental plastic‐covered greenhouses during six consecutive cucumber plantings from 2000 to 2002. Using linear regression analysis of 46 disease‐progress curves, the Gompertz model best described the CYSDV epidemics in 2000, whereas the logistic model best described the development of CYSDV and CVYV epidemics in 2001 and 2002. The fitted models were used to calculate the amount of degree Celsius‐days at half‐maximum infection in the greenhouses (°D0·5). After multiple regression analysis, 56% of the variation in °D0·5 of CYSDV was related to the numbers of whiteflies infesting the cucumber crops, and was independent of the mean temperatures in the greenhouses. In contrast, 76% of the variation in °D0·5 of CVYV was related to both the numbers of vectors present and maximum temperature. Symptom expression in cucumbers mechanically inoculated with CVYV was most prevalent when plants were grown at regimes of at least 28°C day temperature. According to analysis of spread using Taylor's power law, beta‐binomial distribution fitting, and the ordinary runs test, the prevalence of CVYV showed significant overdispersion, whereas that of CYSDV did not. The χ2 test of independence and Spearman's rank correlation coefficient were used to measure co‐occurrence and covariation, respectively, during the first half of the cultivation period. These results showed that the two diseases were not associated.

The complete nucleotide sequence of isolates of Cucumber vein yellowing virus (CVYV) has been determined. The viral genome comprises 9734 nucleotides, excluding a 3'-terminal poly(A) sequence. The genome of CVYV has a 5'-non coding and a 3' non coding region of respectively 67 and 240 nucleotides. The RNA of CVYV encodes a single polyprotein of 3148 amino acid residues and has a deduced genome organization and motifs typical for a member of the family Potyviridae. However, CVYV is atypical because it lacks a coding sequence region for the putative helper-component as well as conserved helper-component-proteinase motifs which may account for its vector relations. All the present coding regions were compared to those from several members of the Potyviridae family. CVYV is most closely related to Sweetpotato mild mottle virus confirming its assignation to the genus Ipomovirus, despite similarities with tritimoviruses.

During the summer of 2004, bell pepper (Capsicum annuum) growing in a plastic-covered greenhouse, Almeria (south-east Spain) showed necrotic stems and fruit with brown patches and corky rings on the surface. Mechanical inoculation of sap from the fruits produced necrotic etching on leaves of Nicotiana tabacum cv. Xanthi, consistent with symptoms produced by members of the genus Ilarvirus. Mechanical transmission from infected N. tabacum to 1-month-old bell pepper seedlings produced symptoms on stems and fruit, similar to those originally observed on field plants. Using total RNA extracts from diseased pepper plants and N. tabacum, RT-PCR analysis using specific primers for Parietaria mottle virus (PMoV) based on GenBank Accession No. AY496068 sequence (forward primer 5′-GATGTTGCCGCCGACGATTCTA-3′ and reverse primer 5′-TTTTCCCACAACCCGCAACAC-3′) produced an amplicon of the expected size (475 bp). Individual amplicons were cloned in Escherichia coli, sequenced and analysed using blast analysis (NCBI, Bethesda, MD, USA). All clones had an identical nucleo-tide sequence (Accession No. AY819660) and showed the highest percentage identity with the P1 gene for the replicase of Parietaria mottle virus (92% nucleotide; 97% amino acid). Following mechanical inoculation, the virus from pepper systemically infected N. tabacum cv. Xanthi, N. tabacum cv. White Burley, Nicotiana glutinosa and Lycopersicon esculentum, as confirmed by RT-PCR testing. No infection was obtained in Chenopodium amaranticolor, Chenopodium quinoa, Solanum melongena, Datura stramonium or Cucumis sativus. The pepper isolate of PMoV was negative in ELISA when analysed with commercial antisera to Tomato spotted wilt virus, Cucumber mosaic virus, Tomato mosaic virus, Alfalfa mosaic virus, Pepper mild mottle virus, Tomato bushy stunt virus, Tobacco necrosis virus, Tobacco mild green mosaic virus and potyvirus. PMoV has been isolated from tomato crops in Italy, France, Greece and Spain (Ramasso et al., 1997; Marchoux et al., 1999; Roggero et al., 2000; Aramburu, 2001). This is the first report of a PMoV isolate with a distinct genome sequence and host range, capable of producing disease in pepper. This work was supported by project PIA 03/31 from the Junta de Andalucía (Spain).

Common bean (Phaseolus vulgaris L.) is grown on approximately 1,500 ha in commercial greenhouses and is of major economic importance in the Souss-Massa Region, Agadir, Morocco. Since October 2003, symptoms resembling a viral disease, consisting of pod mosaic and distortion and mild to severe mosaic in leaves, have been observed on bean plants in several greenhouses. Mechanical inoculation with symptomatic leaf extracts produced necrotic local lesions on P. vulgaris 'Pinto' and systemic symptoms similar to those observed in the naturally infected bean plants P. vulgaris 'Donna' (five plants per cultivar). Inoculated and naturally infected samples reacted positively using a double antibody sandwich enzyme-linked immunosorbent assay (DAS-ELISA) to Southern bean mosaic virus (SBMV) (DSMZ, Braunschweig, Germany), a member of the Sobemovirus genus that is transmitted by contact, soil, beetles, and seeds (1). Virions purified from a naturally infected 'Donna' plant contained a 30-kDa polypeptide that reacted positively using sodium dodecyl sulfate polyacrylamide gel electrophoresis and western blot analysis with SBMV antiserum (DSMZ). Reverse transcription-polymerase chain reaction amplification with SMBV primers as described by Verhoeven et al. (2) produced an expected 870-bp band. The amplicon was cloned, sequenced (GenBank Accession No. AJ748276), and compared to those isolates available in GenBank and had a nucleotide sequence identity of 87% and a derived amino acid sequence identity of 95% with an SBMV isolate from Spain (2). During a survey in different areas of the Souss-Massa Region, 20 symptomatic leaf and pod samples were randomly collected from 12 greenhouses (50 ha) where significant commercial losses were suffered because of this virus disease, and all samples were positive using DAS-ELISA for SBMV. To our knowledge, this is the first report of SBMV in Morocco. References: (1) J. H. Tremaine and R. I. Hamilton. Southern bean mosaic virus. No. 274 in: Descriptions of Plant Viruses. CMI/AAB, Kew, Surrey, England, 1983. (2) J. Th. J. Verhoeven et al. Eur. J. Plant Pathol. 109:935, 2003.

During the autumn of 2003, a new disease was observed in French bean (Phaseolus vulgaris) grown commercially in Spain. Symptoms resembling nutritional disorders consisted of interveinal mottling and yellowing in leaves, combined with stiffness or brittleness, and were produced on the middle to lower parts of the plant. Affected plants were all observed in glasshouses infested with Bemisia tabaci. Reproducible symptoms were observed when the virus was transmitted from bean to bean by B. tabaci (9/10) but not by mechanical inoculation (0/30). Electrophoresis of double-stranded (ds) RNA extractions from field-collected samples and B. tabaci-inoculated plants revealed a high-molecular-weight dsRNA doublet, consistent with the bipartite genome of criniviruses (Celix et al., 1996). cDNA transcripts were produced and amplified by RT-PCR from the agarose-purified dsRNA species by uneven PCR (Chen & Wu, 1997). Individual amplicons were cloned into pGEM-T® Easy Vector (Promega, Madison, WI, USA), sequenced and then analysed using Blastx (NCBI, Bethesda, USA). The nucleotide sequence and deduced amino acid sequence from one amplicon (GenBank accession AY543165) showed the highest percentage identity with the heat shock protein 70 homologue from members of the genus Crinivirus such as Cucurbit yellow stunting disorder virus (CYSDV) (57 and 67%, respectively), Beet pseudo-yellows virus (BPYV) (54 and 63%, respectively) and Tomato chlorosis virus (ToCV) (52 and 57%, respectively). RT-PCR analysis with designed specific primers (forward primer 5′-TTATGTATGATCTAGGCGGAGGTC-3′ and reverse primer 5′-CTGGGTCAATGATACAAGTTAGTC-3′) produced an amplicon of the expected size (465 bp), when using total RNA extracts from diseased plants and viruliferous whiteflies. This is the first report of a yellowing disorder in bean associated with a B. tabaci-transmitted virus, with molecular and epidemiological features consistent with criniviruses (Wisler et al., 1998). Based on the host range and the unique partial genome sequence, the name Bean yellow disorder virus (BnYDV) is proposed to describe this new virus. This work was supported with project PIA 03/31 from the Junta de Andalucía (Spain).

En 1998 comenzaron a observarse anormalidades en plantaciones de judia (Phaseolus vulgaris L.) para consumo en fresco en invernaderos de Castell de Ferro y Lujar (Granada) y de Balanegra y Balerma (Almeria) causantes de importantes mermas economicas debido a que las vainas perdian calidad y valor comercial. La diseminacion de la enfermedad fue muy rapida durante la recoleccion, ya que en esta fase del cultivo la enfermedad se extendia por toda la plantacion en pocos dias, llegando en algunos casos a perderse casi la totalidad de la cosecha. En el ano 2001 identificamos el origen de la enfermedad como un virus no descrito antes en Espana, cuyo acido nucleico es ARN de cadena sencilla (+), perteneciente al genero Sobemovirus denominado Southern bean mosaic virus (SBMV) (Segundo et al., 2002; Verhoeven et al., 2003), tambien conocido como virus del mosaico sureno de la judia o de la caraota y sinonimo de Bean southern mosaic virus. Este virus fue descrito por primera vez en 1943 procedente de cultivos infectados de judia en Lousiana y California (Zaumeyer y Harter, 1943b); ademas, se han descrito diversas cepas que afectan a otros huespedes naturales tales como caupi (Vigna unguiculata), frijol urd (V. Mungo) y soja (Glycine max). Esta enfermedad se ha desarrollado en las principales zonas productoras de judia para consumo en fresco localizadas en el sur espanol, habiendose observado en los ultimos meses un espectacular incremento de los cultivos afectados en Almeria, que se ha reflejado en los analisis realizados por el Laboratorio de Sanidad Vegetal de Almeria, apareciendo SBMV en 2003 como el virus que mas afecto a judia, con un incremento del 30% de judias enfermas respecto a 2002. Actualmente no hay constancia de la presencia de esta virosis en el resto de Espana ni en Europa, aunque se cito en 1969 un virus similar a SBMV afectando a cultivos de judia en el distrito de Paris (Ferault et al., 1969). Sin embargo, SBMV esta ampliamente extendido en las zonas productoras de judia para grano en el continente latinoamericano representando uno de los principales patogenos de origen viral que afectan a judia en Venezuela, en donde se ha sugerido la introduccion del virus por semillas contaminadas importadas de Colombia (Garrido y Savini, 1997; Pena y Trujillo, 2001; Trujillo y Garrido, 2001). Tambien se ha destacado la presencia del virus en Mexico y Brasil (Gergerich, 1994; Moreira y Gaspar, 2002), asi como en otras zonas del globo como Norteamerica, Asia y Africa (Tremaine y Hamilton, 1983).

Southern bean mosaic virus (SBMV) has been identified as the cause of a new disease in greenhouse-cultivated common bean (Phaseolus vulgaris), in the south-east of Spain. The identification was based on host range comparisons, morphological and serological characteristics of the virus, the size of its dsRNA species and the nucleotide sequence of an 810-bp fragment from ORF2. The virus could be clearly discriminated from the related sobemovirus Southern cowpea mosaic virus. This is the first report of SBMV in Spain.