First Report of Bean Leafroll Luteovirus Infecting Pea in Italy

Approximately 5,000 ha of processing peas (Pisum sativum L) are cultivated annually in the Po River Valley of northern Italy. During the 1998 growing season, affected pea plants in this region were observed that exhibited mild chlorosis and mottling, leaf rolling, and stunting symptoms. High aphid populations and disease levels of nearly 100% were observed in susceptible varieties. Samples from affected fields were analyzed for the presence of bean leafroll virus (BLRV). Nonviruliferous pea aphids (Acyrthosiphon pisum Harris) received a 48-h acquisition access period on symptomatic leaves. Aphids were then transferred to Puget pea and Diana faba bean for a 72-h inoculation access period. Leaf samples were also macerated in 0.05 M potassium phosphate pH 7.4, and inoculated mechanically to pea, faba bean, chickpea (Cicer arietinum L.), Chenopodium quinoa Willd., and C. amaranticolor Coste & Reyn. Symptoms typical of those observed in the original field plants appeared 10 to 14 days after aphid transmissions in both pea and faba bean inoculated with pea aphids. No symptoms were observed in any of the hosts that were inoculated mechanically. Total nucleic acid extracts from the original pea samples, and from leaf tissue of pea and faba bean plants inoculated with aphids, served as templates in reverse-transcriptase polymerase chain reaction assays. Primers BLR-V157 and BLR-C546, which flanked a 400-bp fragment, were designed with available sequence data for the coat protein gene of BLRV (1). An amplification product of the expected size was generated from symptomatic plants but not from healthy controls. Sequence analysis of the cloned fragments revealed a 99% nucleic acid homology with the published sequence for BLRV and an isolate obtained from alfalfa in Washington State (R. Larsen, unpublished). This is the first report of BLRV in Italy. Reference: (1) B. Brill et al. Nucleic Acids Res. 18:5544, 1990.

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First Report of Beet mosaic virus Infecting Chickpea (Cicer arietinum) in Tunisia

Plant Disease ◽

10.1094/pdis-94-8-1068c ◽

2010 ◽

Vol 94 (8) ◽

pp. 1068-1068 ◽

Cited By ~ 3

Author(s):

S. G. Kumari ◽

A. Najar ◽

N. Attar ◽

M. H. Loh ◽

H.-J. Vetten

Keyword(s):

Mosaic Virus ◽

Faba Bean ◽

Acyrthosiphon Pisum ◽

Broad Bean ◽

Leaf Roll ◽

Infected Plant ◽

Potassium Phosphate ◽

Leaf Tissue ◽

Negative Control ◽

Yellow Mosaic Virus

Chickpea plants with severe yellowing and tip wilting were observed in the Cap-Bon Region of Tunisia in 2006. The viral-like symptoms resulted in yield loss of approximately 25% in some fields. A total of 110 symptomatic chickpea plants was collected from nine chickpea fields and tested at the Virology Laboratory of ICARDA, Syria for eight legume viruses using tissue-blot immunoassay (TBIA) (3). Polyclonal antisera produced at the ICARDA Virology Laboratory were used to test for Chickpea chlorotic dwarf virus (genus Mastrevirus, family Geminiviridae), Broad bean stain virus (genus Comovirus, family Secoviridae), Broad bean mottle virus (genus Bromovirus, family Bromoviridae), and Bean yellow mosaic virus and Pea seed borne mosaic virus (genus Potyvirus, family Potyviridae). Antiserum to Beet mosaic virus (BtMV; genus Potyvirus, family Potyviridae) (AS-0143) was provided by the German Collection of Microorganisms and Cell Cultures (DSMZ, Braunschweig, Germany). In addition, three monoclonal antibodies (MAb) were used to detect Faba bean necrotic yellows virus (FBNYV; genus Nanovirus, family Nanoviridae) (MAb 3-2E9) (1), potyviruses (PVAS-769 [MAb PTY 3 Potyvirus Group] American Type Culture Collection, Manassas, VA), and luteoviruses (MAb B-2-5G4) (2). Twenty-two of the plants tested positive with MAb PTY 3 and BtMV antisera, 56 samples reacted with MAb B-2-5G4, and eight plants with the FBNYV MAb, whereas 24 plants tested negative with all antisera. Because reactions with the BtMV antiserum were unexpected, detection of BtMV was confirmed by reverse transcription-(RT)-PCR assays using BtMV-specific primers (LN26 and LN27) (4), which produced an amplicon of expected size (1,050 bp) from all plants that reacted with BtMV antiserum but not from plants that were serologically negative. Leaf tissue from a BtMV-infected plant was ground in 0.01 M potassium phosphate buffer, pH 7.2 (1:20, wt/vol), mixed with 0.5% celite, and used for mechanical inoculation of chickpea seedlings (cv. Beja 4). In addition, adults of three legume aphid species (Aphis craccivora, A. fabae, and Acyrthosiphon pisum) were starved for 1 h before feeding on BtMV-infected chickpea leaves for an acquisition access period of 5 min. Fifteen aphids of each species were placed on each chickpea plant, allowed to feed for 24 h, and then sprayed with an insecticide. Tip wilting symptoms appeared on plants 15 to 20 days after mechanical and aphid inoculations but not on plants used as negative control treatments (inoculated mechanically with healthy leaf tissue or with aphids that had fed on noninfected chickpea plants). Use of BtMV antiserum for TBIA analysis of inoculated plants revealed systemic BtMV infections in 35 of 92 plants inoculated mechanically and 15 of 75 plants inoculated with viruliferous A. fabae only. To our knowledge, this is the first record of BtMV infecting chickpea in Tunisia. References: (1) A. Franz et al. Ann. Appl. Biol. 128:255, 1996. (2) L. Katul. Characterization by serology and molecular biology of bean leaf roll virus and faba bean necrotic yellows virus. Ph.D. thesis. University of Gottingen, Germany, 1992. (3) K. M. Makkouk and A. Comeau. Eur. J. Plant Pathol. 100:71, 1994. (4) L. G. Nemchinov et al. Arch. Virol. 149:1201, 2004.

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FABA BEAN: LOW RESISTANCE TO PEA APHIDS, ACYRTHOSIPHON PISUM (HOMOPTERA: APHIDIDAE), IN ELEVEN CULTIVARS

Canadian Journal of Plant Science ◽

10.4141/cjps76-074 ◽

1976 ◽

Vol 56 (3) ◽

pp. 451-453 ◽

Cited By ~ 4

Author(s):

B. D. FRAZER ◽

D. RAWORTH ◽

T. GOSSARD

Keyword(s):

Vicia Faba ◽

Faba Bean ◽

Acyrthosiphon Pisum ◽

Broad Bean ◽

Developmental Rate ◽

Low Resistance ◽

Pea Aphids ◽

Vicia Faba L ◽

Faba Beans

Eleven cultivars of faba beans and one of broad bean (Vicia faba L.) were bioassayed for resistance to pea aphids (Acyrthosiphon pisum (Harris)) by determining the fecundity, survival and developmental rate of the aphid on each cultivar. None of the cultivars tested, including the three licensed for production in Canada, possess any significant resistance, although they differ in susceptibility.

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First Report of Downy Mildew Caused by Peronospora trigonellae on Fenugreek in the United States

Plant Disease ◽

10.1094/pdis-93-12-1349a ◽

2009 ◽

Vol 93 (12) ◽

pp. 1349-1349 ◽

Cited By ~ 1

Author(s):

S. Rooney-Latham ◽

C. L. Blomquist ◽

J. Turney

Keyword(s):

United States ◽

Los Angeles ◽

Sequence Data ◽

Leaf Tissue ◽

The United States ◽

Grocery Store ◽

Diagnostic Laboratory ◽

First Report ◽

Severe Stunting ◽

The United Kingdom

Fenugreek (Trigonella foenum-graecum) is a member of the Fabaceae family and is grown worldwide for culinary and medicinal purposes. The leaves are used as an herb while the seeds are used whole, ground as a spice, or germinated and used as sprouts. In November 2008, a fenugreek plant exhibiting leaf spotting and severe stunting was submitted to the CDFA Plant Pest Diagnostics Laboratory from the Los Angeles County Plant Diagnostic Laboratory. The county had received the sample from a homeowner who reported severe dieback of the fenugreek in his backyard planting. The fenugreek is grown by the resident as an annual and is propagated each year from the previous crop's seed. The seed was originally obtained from a local ethnic grocery store in Lakewood, CA. The homeowner stated that he had noticed symptoms for a number of years and that they seemed especially severe during the winter months. The adaxial surfaces of the leaves exhibited small chlorotic spots often at the leaf margins, while the abaxial surfaces exhibited a grayish violet, felty growth. Conidiophores found on the underside of the leaves branched dichotomously 6 to 10 times and were terminally forked. Conidiophores measured 280 to 525 μm (average 420 μm) with slightly swollen bases (7.5 to 10 μm broad). Conidia were slightly pigmented, oblong to ellipsoid, and measured 23 to 33 × 18 to 23 μm (average 27.8 × 20.3 μm). Globose oospores with verruculose walls measured 30 to 40 μm in diameter (average 36.1 μm) and were found embedded in the leaf tissue of older lesions. The pathogen was identified morphologically as Peronospora trigonellae Gaum. (3). Sequences of a portion of the rDNA, including the internal transcribed spacer regions, were obtained using primers DC6 and ITS6 (1). Sequence data for P. trigonellae had not previously been entered into GenBank and no identity was obtained. Pathogenicity experiments attempted by spraying healthy fenugreek seedlings with conidial suspensions were unsuccessful, presumably because of the age of the inoculum. Since fenugreek is not commercially grown in California, the economic importance of this disease is limited. Although P. trigonellae has been reported on fenugreek in Algeria, India, Pakistan, and the United Kingdom (2–4), to our knowledge, this is the first report of its occurrence in California and the United States. A specimen of P. trigonellae has been deposited in the U.S. National Fungus Collection (BPI 879153). References: (1) D. E. L. Cooke et al. Fungal Genet. Biol. 30:17, 2000. (2) D. F. Farr et al. Fungal Databases. Systematic Mycology and Microbiology Laboratory. Online publication. ARS, USDA, 2009, (3) E. A. Gaumann. Beitr. Kryptogamenflora Schweiz 5:216, 1923. (4) D. R. Jones et al. Plant Pathol. 56:891, 2007.

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First Report of Bacterial Blight of Crucifers Caused by Pseudomonas cannabina pv. alisalensis in Minnesota on Arugula (Eruca vesicaria subsp. sativa)

Plant Disease ◽

10.1094/pdis-10-14-1020-pdn ◽

2015 ◽

Vol 99 (3) ◽

pp. 415-415 ◽

Cited By ~ 1

Author(s):

C. T. Bull ◽

M. C. Ortiz-Lytle ◽

A. G. Ibarra ◽

L. J. du Toit ◽

G. Reynolds

Keyword(s):

Bacterial Blight ◽

Cropping Systems ◽

Potassium Phosphate ◽

Leaf Tissue ◽

Positive Control ◽

Hypersensitive Reaction ◽

Bacterial Strains ◽

Banding Patterns ◽

First Report ◽

Initial Symptoms

In 2011, bacterial blight of arugula (Eruca vesicaria subsp. sativa; cv. Roquette) was observed in organically grown plants under overhead irrigation in a field near Delano, MN. Approximately 80 to 100% of each planting was affected, with greater rates of infection occurring after periods of high humidity. Small, water-soaked, angular spots apparent on both sides of the leaves comprised the initial symptoms, which sometimes expanded and coalesced. Lesions maintained a dark water-soaked appearance or dried and turned a brown/tan color. Additionally, some lesions were outlined by a purple margin. Blue-green fluorescent pseudomonads were isolated consistently on King's Medium B agar (KMB) from symptomatic leaf tissue surface-disinfested with sodium hypochlorite (0.525%). The isolates nucleated ice and produced levan. Isolates were oxidase and arginine dihydrolase negative. They did not rot potato slices but did induce a hypersensitive reaction in tobacco (Nicotiana tabacum cv. Samsun). These data indicated that the bacteria belonged to Lelliott's LOPAT group 1 (2). DNA fragment banding patterns generated by amplifying DNA of the arugula isolates using repetitive extragenic palindromic sequence–polymerase chain reaction (rep-PCR) and the BOX A1R primer were identical and nearly identical to the banding patterns of the Pseudomonas cannabina pv. alisalensis (formerly P. syringae pv. alisalensis) (1) strain (CFBP1637) and the pathotype strain (CFBP 6866PT), respectively. Pathogenicity was confirmed on the arugula cv. My Way in two independent experiments, each with three replicate plants per treatment. Four isolates were grown on KMB for 48 h at 27°C, suspended in 0.01M potassium phosphate buffer (pH 7.0), and adjusted to 0.6 optical density at 600 nm (approximately 1 × 108 CFU/ml). Five- to six-week old plants were spray-inoculated until run-off, incubated in a humidity chamber for 48 h, and then placed in a greenhouse at 20 to 25°C for symptom development. For negative and positive control treatments, a similar number of plants each were sprayed with sterile buffer or P. cannabina pv. alisalensis strains CFBP1637 and CFBP 6866PT, respectively. Water-soaked and brown/tan lesions similar to the original symptoms appeared on plants inoculated with the arugula isolates and P. cannabina pv. alisalensis strains 7 to 14 days postinoculation. No symptoms developed on plants treated with sterile buffer. The bacterial strains re-isolated from surface-disinfested symptomatic tissue were identical by rep-PCR to the isolates used to inoculate the plants, thus, confirming Koch's postulates. Identical replicated experiments conducted on broccoli raab indicated that the arugula isolates were also pathogens of broccoli raab (Brassica rapa subsp. rapa, the original host from which P. cannabina pv. alisalensis was isolated). To our knowledge, this is the first report of bacterial blight of crucifers caused by P. cannabina pv. alisalensis in Minnesota. Arugula germplasm is being evaluated for resistance to this pathogen as an acceptable management method for organic cropping systems. References: (1) C. T. Bull et al. Syst. Appl. Microbiol. 33:105, 2010. (2) R. A. Lelliott. J. Appl. Bacteriol. 29:470, 1966.

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First Report of Red Clover Vein Mosaic Carlavirus Naturally Infecting Lentil

Plant Disease ◽

10.1094/pdis.1998.82.9.1064a ◽

1998 ◽

Vol 82 (9) ◽

pp. 1064-1064 ◽

Cited By ~ 3

Author(s):

R. C. Larsen ◽

J. R. Myers

Keyword(s):

Pacific Northwest ◽

Acyrthosiphon Pisum ◽

Sequence Data ◽

Natural Infection ◽

Red Clover ◽

Enzyme Linked Immunosorbent Assay ◽

Chenopodium Amaranticolor ◽

First Report ◽

Severe Stunting ◽

Bait Plants

Lentil (Lens culinaris Medik.) is an important legume crop grown in the dryland Pacific Northwest areas of eastern Washington and Oregon, and northern Idaho. Lentil is highly susceptible to pea enation mosaic enamovirus (PEMV) and bean leafroll luteovirus (BLRV), and infection may result in severe yield losses. Recently, lentil was also found to be infected experimentally with red clover vein mosaic carlavirus (RCVMV) (1). The virus is most commonly transmitted in the Pacific Northwest by the pea aphid (Acyrthosiphon pisum Harris) in a nonpersistent manner. In 1997, cv. Brewer lentil bait plants were planted at the Vegetable Research Farm at Oregon State University to monitor incidence of PEMV and BLRV. Many of the plants developed symptoms typical of PEMV. However, other plants exhibited severe stunting, proliferation of axillary branches, and general chlorosis or death. Bait plants were harvested in August, and 204 random samples were tested for PEMV, RCVMV, BLRV, alfalfa mosaic alfamovirus (AMV), and pea streak carlavirus (PeSV) by standard enzyme-linked immunosorbent assay (ELISA) protocols. Antiserum for RCVMV was made in the Prosser lab against an isolate from chickpea collected in Washington State (1). RCVMV was detected in 76 (34%) of the 204 samples. PEMV, AMV, BLRV, and PeSV were detected in 197 (89.5%), 23 (11.3%), 2 (0.9%), and 0 (0%) of samples, respectively. Results showed that 75/76 of the samples positive for RCVMV were also coinfected with PEMV. Plants infected with RCVMV in the greenhouse also produced mild systemic mosaic symptoms in selected hosts inoculated mechanically, including pea (Pisum sativum L.), chickpea (Cicer arietinum L.), faba bean (Vicia faba L.), and lentil. Lentil and chickpea also showed moderate to severe stunting. Chlorotic local lesions were formed on Chenopodium amaranticolor Coste & Reyn. and C. quinoa Willd. Oligonucleotide primers were designed with sequence data obtained from the Washington isolate of RCVMV (1), and identification of the virus was verified in pea and lentil by polymerase chain reaction (PCR). Primer design of RCV34V and RCV653C targeted a 619-bp fragment located in the viral coat protein gene. Plants testing positive by ELISA yielded PCR products of the expected size when visualized on agarose gels. This is the first report of natural infection of lentil by RCVMV. Reference: (1) R. C. Larsen et al. Phytopathology 87:S56, 1997.

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First Report of Leaf Spot Caused by Cladosporium perangustum on Syagrus oleracea in Brazil

Plant Disease ◽

10.1094/pdis-06-13-0595-pdn ◽

2014 ◽

Vol 98 (2) ◽

pp. 280-280 ◽

Cited By ~ 6

Author(s):

R. R. Oliveira ◽

R. L. Aguiar ◽

D. J. Tessmann ◽

W. M. C. Nunes ◽

A. F. Santos ◽

...

Keyword(s):

Leaf Spot ◽

Sequence Data ◽

Elongation Factor ◽

Leaf Tissue ◽

Unknown Etiology ◽

Palm Tree ◽

First Report ◽

Potted Plants ◽

Central Brazil ◽

Dna Sequence Data

Syagrus oleracea (Mart.) Becc. (bitter coconut), a palm tree species that is native to central Brazil, has been increasingly cultivated in this country for heart-of-palm production. Epidemics of a necrotic leaf spot of unknown etiology have been recorded on bitter coconut plants in transplant nurseries and plantation since 2008. The first symptoms appear as small, yellow, hydrotic flecks on young or mature leaves that evolve to necrotic brown streaks that run parallel to the leaf veins. Usually, yellow halos occur around the lesions and hydrosis is common during lesion expansion. Necrotic lesions can reach up to 40 mm in length and 10 mm in width, and the lesions often coalesce, causing extensive tissue damage. During a survey in a 3-year-old bitter coconut plantation in Maringá County (coordinates: 23°23′51.25″ S, 51°57′02.09″ W; elevation: 507 m) in the state of Parana, a dozen symptomatic leaves were collected with the aim of elucidating the etiology of this disease. Conidia and conidiophores typical of Cladosporium were frequently observed on the diseased leaf tissue under natural field conditions as well on the surfaces of disinfected leaf tissues kept in a humid chamber for 48 h at 25 ± 2°C with a 12-h photoperiod. Five monoconidial cultures growing on potato dextrose agar (PDA) medium were obtained from different leaves showing leaf spot symptoms. The cultures were grown on PDA to induce sporulation. At 7 days after incubation at 25 ± 2°C and a 12-h photoperiod, gray to gray-olive colonies were observed. The conidiophores were macronematous, erect, oblong, branched, 1 to 5 septate, and 75.0 to 120.0 × 1.90 to 3.20 μm. The ramoconidia were cylindrical or oblong, 0 to 2 septate, and 28.0 to 40.0 × 2.8 to 3.6 μm, with a truncate base of 1.9 to 2.2 μm; secondary ramoconidia were cylindrical or oblong, 0 to 2 septate, 8.0 to 31.0 × 2.2 to 3.1 μm, with 3 to 5 distal conidial hila; intercalary 1-septate conidia were 5.5 to 17.0 × 2.1 to 3.4 μm, with 1 to 3 distal conidial hila; terminal 1-septate conidia were catenulate and 2.2 to 4.2 × 1.8 to 3.1 μm. Species identification was performed based on morphology and DNA sequence data (1). Portions of the elongation factor 1α (551 bp; TEF) and actin (213 bp; ACT) genes were amplified by PCR. A BLAST search of the GenBank database revealed that the TEF (KC484658 to KC484662) and ACT (KC484663 to KC484667) sequence fragments from isolates Gua1, Gua2, Gua3, Gua4, and Gua5 had 100% identity with the accessions HM148616 and HM148371 of Cladosporium perangustum (1). Isolates were tested for pathogenicity against bitter coconut. Ten potted plants with 4 to 6 fully expanded leaves were inoculated with each isolate by spraying a suspension of conidia (105 spores per ml) onto leaves until runoff using a handheld spray bottle. Non-inoculated controls (10 plants) were sprayed with distilled water. The plants were kept in a humid plastic chamber at 20 to 26°C. All examined isolates were pathogenic to bitter coconut, causing symptoms identical to those described above 12 days after inoculation. All inoculated tissues were plated onto PDA to confirm the presence of the pathogen. Live cultures are being maintained at the Micoteca/URM/UFPE ( www.ufpe.br/micoteca ), Brazil. To our knowledge, this is the first report of a disease caused by C. perangustum on S. oleracea worldwide, and the study provides valuable plant disease diagnostic information for the palm hearth industry in Latin America. Reference: (1) K. Bensch et al. Stud Mycol. 67:1, 2010.

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Survival and Development ofChrysoperla rufilabris(Neuroptera: Chrysopidae) Supplied with Pea Aphids (Homoptera: Aphididae) Reared on Alfalfa and Faba Bean

Environmental Entomology ◽

10.1093/ee/29.2.304 ◽

2000 ◽

Vol 29 (2) ◽

pp. 304-311 ◽

Cited By ~ 12

Author(s):

Kristopher L. Giles ◽

Robin D. Madden ◽

Mark E. Payton ◽

Jack W. Dillwith

Keyword(s):

Faba Bean ◽

Pea Aphids ◽

Survival And Development

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Occurrence and Origin of Supernumerary Chromosomes in Partamona (Hymenoptera: Apidae: Meliponini)

Cytogenetic and Genome Research ◽

10.1159/000452290 ◽

2016 ◽

Vol 150 (1) ◽

pp. 68-75 ◽

Cited By ~ 1

Author(s):

Diana P. Machado ◽

Elder A. Miranda ◽

Mariana C. Dessi ◽

Camila P. Sabadini ◽

Marco A. Del Lama

Keyword(s):

High Frequency ◽

Scar Marker ◽

Sequence Data ◽

Low Frequency ◽

B Chromosomes ◽

First Report ◽

Supernumerary Chromosomes

Samples from 861 colonies of 12 Partamona species from 125 Brazilian localities were analysed for a SCAR marker specific to the B chromosomes of P. helleri. We identified the SCAR marker in 6 of the 12 species analysed, including 2 (P. gregaria and P. chapadicola) from the pearsoni clade. This is the first report on the presence of this marker in Partamona species that are not included in the cupira clade, which indicates that the B chromosomes probably are more widespread in this genus than previously thought. The analysis revealed a high frequency of the SCAR marker in the samples of P. helleri (0.47), P. cupira (0.46), and P. rustica (0.29), and a low frequency in P. aff. helleri (0.06). The frequency of the marker in P. helleri was correlated with the latitude of the sampling locality, decreasing from north to south. Sequence data on the SCAR marker from 50 individuals of the 6 species in which the presence of this marker was shown revealed a new scenario for the origin of the B chromosomes in Partamona.

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First Report of Leptosphaeria biglobosa (Blackleg) on Brassica oleracea (Cabbage) in Mexico

Plant Disease ◽

10.1094/pdis-94-6-0791c ◽

2010 ◽

Vol 94 (6) ◽

pp. 791-791 ◽

Cited By ~ 10

Author(s):

A. Dilmaghani ◽

M. H. Balesdent ◽

T. Rouxel ◽

O. Moreno-Rico

Keyword(s):

Brassica Oleracea ◽

Sequence Data ◽

Leptosphaeria Maculans ◽

The United States ◽

Internal Transcribed Spacers ◽

First Report ◽

5.8S Rdna ◽

Single Location ◽

Leptosphaeria Biglobosa ◽

Β Tubulin

Broccoli (Brassica oleracea var. italica), cauliflower (B. oleracea var. botrytis), and cabbage (B. oleracea var. capitata) have been grown in central Mexico since 1970, with 21,000 ha cropped in 2001. In contrast, areas grown with oilseed rape (B. napus) are very limited in Mexico (<8,000 ha). Blackleg, a destructive disease of B. napus in most parts of the world, was first observed in Mexico in Zacatecas and Aguascalientes in 1988 on B. oleracea, causing as much as 70% yield loss. A species complex of two closely related Dothideomycete species, Leptosphaeria maculans and L. biglobosa, is associated with this disease of crucifers (1), but leaf symptoms on susceptible plants are different, with L. maculans typically causing >15-mm pale gray lesions with numerous pycnidia, whereas L. biglobosa causes dark and smaller lesions only containing a few pycnidia. Having a similar epidemiology, both species can be present on the same plants at the same time, and symptom confusion can occur as a function of the physiological condition of the plant or expression of plant resistance responses. A total of 209 isolates from symptomatic B. oleracea leaves were collected from three fields in central states of Mexico (58 to 71 isolates per location). All leaves showed similar symptoms, including a 10- to 15-mm tissue collapse with an occasional dark margin. Cotyledons of seven B. napus differentials were inoculated with conidia of all the isolates as described by Dilmaghani et al. (1). Two hundred isolates caused tissue collapse typical of L. maculans. However, nine obtained from white cabbage in a single location in Aguascalientes caused <5-mm dark lesions. When inoculated onto cotyledons of three B. oleracea genotypes commonly grown in Mexico (cvs. Domador, Monaco, and Iron Man), the nine isolates caused a range of symptoms characterized by tissue collapse (maximum 10 to 15 mm), showing the presence of patches of black necrotic spots within the collapse. The occasional presence of a few pycnidia allowed us to reisolate the fungus for molecular identification. ITS1-5.8S-ITS2, (internal transcribed spacers and 5.8S rDNA), actin, and β-tubulin sequences were obtained as described previously (4). Multiple gene genealogies based on these sequence data showed two subclades of L. biglobosa: L. biglobosa ‘occiaustralensis’ (one isolate; ITS [AM410082], actin [AM410084], and β-tubulin [AM410083]) and L. biglobosa ‘canadensis’ (eight isolates; ITS [AJ550868], actin [AY748956], and β-tubulin [AY749004]) (3,4), which were previously described on B. napus in the United States, Canada, and Chile. To our knowledge, this is the first report of L. biglobosa in Mexico. Previously, this species has only been reported once on B. oleracea without discrimination into subclades (2). In the Aguascalientes sampling, 24% of the isolates were L. biglobosa, similar to Canadian locations where this species is still common as compared with L. maculans (1). The large proportion of sampled L. biglobosa ‘canadensis’, highlights the prevalence of this subclade throughout the American continent (1). References: (1) A. Dilmaghani et al. Plant Pathol. 58:1044, 2009. (2) E. Koch et al. Mol. Plant-Microbe Interact. 4:341, 1991. (3) E. Mendes-Pereira et al. Mycol Res. 107:1287, 2003. (4) L. Vincenot et al. Phytopathology 98:321, 2008.

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First Detection of Faba bean necrotic yellow virus in Spain

Plant Disease ◽

10.1094/pdis.2000.84.6.707b ◽

2000 ◽

Vol 84 (6) ◽

pp. 707-707 ◽

Cited By ~ 7

Author(s):

M. Babin ◽

V. Ortíz ◽

S. Castro ◽

J. Romero

Keyword(s):

Faba Bean ◽

Acyrthosiphon Pisum ◽

Virus Disease ◽

Epidemiological Data ◽

Aphid Transmission ◽

Enzyme Linked Immunosorbent Assay ◽

Yellow Virus ◽

Potential Threat ◽

Bean Plants ◽

Faba Beans

Faba bean necrotic yellow virus (FBNYV) was not detected during 1994 to 1996 field surveys of faba beans (Vicia faba L.) in Spain (1). In 1997, however, one sample with symptoms of necrosis, collected in Baleares, was tested using ELISA (enzyme-linked immunosorbent assay) and was positive for both Tomato spotted wilt virus (TSWV) and FBNYV. FBNYV is a single-strand DNA virus that is transmitted by aphids and is the main virus disease of broad bean in North Africa and West Asia (2). During 1997 to 1999, faba bean plants with symptoms of necrosis, yellowing, small leaves, and stunting were collected from several fields in the Murcia Region (Spain) and were analyzed using ELISA. To detect FBNYV, we used monoclonal 2E9 supplied by H. J. Vetten (Institute of Plant Virology, Microbiology and Biosafety, BBA, Braunschweig, Germany). Of 700 samples analyzed, 34 were positive for FBNYV. Of the 34 positive samples, 12 tested positive, using commercial antiserum from Loewe, Inc. (Munich) for mixed infections with TSWV. FBNYV was transmitted to healthy faba bean plants by aphids (Acyrthosiphon pisum) in greenhouse experiments and was confirmed by ELISA. Preliminary epidemiological data showed a gradual increase in the number of plants infected with time in the same field. Aphid transmission of FBNYV to faba beans has established the disease in Spain and is a potential threat to other leguminous crops. This is the first report of a nanovirus in Europe. References: (1) J. Fresno et al. Plant Dis. 81:112, 1997. (2) L. Katul et al. Ann. Appl. Biol. 123:629, 1993.

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