Further studies on the incidence of virus infection in white clover pastures

1997 ◽  
Vol 48 (1) ◽  
pp. 31 ◽  
Author(s):  
S. J. McKirdy ◽  
R. A. C. Jones
Keyword(s):  
Virus Infection ◽  
Mosaic Virus ◽  
Perennial Ryegrass ◽  
White Clover ◽  
Barley Yellow Dwarf Virus ◽  
Alfalfa Mosaic Virus ◽  
Virus Transmission ◽  
Subterranean Clover ◽  
Enzyme Linked Immunosorbent Assay ◽  
Yellow Dwarf Virus

Leaf samples of white clover were collected from 19 irrigated white clover (Trifolium repens) pastures in the south-west of Western Australia and tested for virus infection by enzyme-linked immunosorbent assay. Clover yellow vein virus (CYVV) was found in 16 pastures at infection levels of up to 23% and white clover mosaic virus (WCMV) in 10 at levels up to 83%. None of the white clover pastures with a high incidence of WCMV had been resown with white clover within the last 10 years, whereas those resown within the last 5 years had little or no infection. As previously reported in tests on different white clover pastures in the same irrigation area, widespread infection with alfalfa mosaic virus (AMV) and occasional infection with subterranean clover red leaf virus (SCRLV) was also found. Two or more viruses were found within 16 of the pastures with at least 3 having all 4 viruses. AMV and WCMV were detected in flatweed (Hypochaeris glabra) and AMV was detected in clustered dock (Rumex conglomeratus), both commonly occurring weeds in the pastures. In tests on the perennial ryegrass (Lolium perenne) component of 18 white clover pastures, infection with barley yellow dwarf virus was found in 14 at levels up to 5%. In addition, 11 of the pastures contained a virus which reacted with potyvirus-specific monoclonal antibodies, presumably ryegrass mosaic virus (RyMV), which was detected at levels up to 34%. Live aphids were trapped at 8 different times during 1995 in one pasture that was infected with WCMV, CYVV, AMV, and SCRLV. Blue-green aphid (Acyrthosiphon kondoi) and oat aphid (Rhopalosiphum padi) were the only species caught, both reaching peak populations in midwinter, but only the latter was found in summer. No virus transmission was detected when the aphids caught were fed individually on subterranean clover (T. subterraneum) indicator plants. It is concluded that WCMV poses a threat to the productivity of white clover within irrigated pastures, especially when present in mixed infection with AMV. CYVV is also commonly found but normally not at high enough incidences to pose a serious threat. RyMV may pose a threat to the productivity of the perennial ryegrass component within white clover-based pastures.

scholarly journals First Report of Soilborne Wheat Mosaic Virus in the United Kingdom

Plant Disease ◽  
1999 ◽  
Vol 83 (9) ◽  
pp. 880-880 ◽  
Author(s):  
G. R. G. Clover ◽  
D. M. Wright ◽  
C. M. Henry
Keyword(s):  
United Kingdom ◽  
Mosaic Virus ◽  
Barley Yellow Dwarf Virus ◽  
Protein A ◽  
The United States ◽  
Enzyme Linked Immunosorbent Assay ◽  
Barley Yellow Dwarf ◽  
The United Kingdom ◽  
Field Samples ◽  
Yellow Dwarf Virus

In April 1999, severe soilborne wheat mosaic virus (SBWMV) symptoms were observed in five fields of winter wheat (Triticum aestivum, cvs. Consort, Equinox, and Savannah) on one farm in Wiltshire, UK. Affected plants were markedly stunted and had a pale mosaic on their leaf sheaths that developed into bright yellow, parallel streaks on the leaves as they unfolded. Symptomatic plants were found in discrete, elliptical patches ranging in size from a few square meters to nearly a hectare. During May and June, symptoms became less marked as temperatures increased and were restricted to lower leaves. SBWMV was positively identified in all five fields (60 to 170 plants per field) by double (W. Huth, BBA-Braunschweig, Germany; Sanofi Phyto-Diagnostics, Paris) and triple (T. Wilson, SCRI, Dundee, UK) antibody sandwich enzyme-linked immunosorbent assay and by reversetranscription polymerase chain reaction (2). Identification was confirmed by immunoelectron microscopy, including protein-A gold labeling, which revealed bipartite, rod-shaped particles typical of SBWMV. Neither wheat spindle streak mosaic virus nor barley yellow dwarf virus was detected in the field samples, nor was SBWMV detected in any other field subsequently sampled, despite a survey of the surrounding area. Wheat is the most important economic crop in the United Kingdom (≈1.9 million hectares are grown annually, yielding ≈16 million tonnes), but its position is threatened by the economic impact of SBWMV, which has decreased yields by up to 50% in the United States (1). References: (1) T. A. Kucharek and J. H. Walker. Plant Dis. Rep. 58:763, 1974. (2) R. E. Pennington et al. Plant Dis. 77:1202, 1993.

Viruses of New Zealand pasture grasses and legumes: a review

2014 ◽  
Vol 65 (9) ◽  
pp. 841 ◽  
Author(s):  
P. L. Guy
Keyword(s):  
New Zealand ◽  
Mosaic Virus ◽  
Resistance Genes ◽  
Barley Yellow Dwarf Virus ◽  
Cropping Systems ◽  
Alfalfa Mosaic Virus ◽  
Plant Viruses ◽  
Future Research ◽  
Pasture Grasses ◽  
Yellow Dwarf Virus

This article reviews knowledge of 23 plant viruses infecting pasture grasses and legumes in New Zealand. The incidence, ecology and impact of each virus and prospects for control using natural or artificial resistance genes or by vector control is discussed. The most prevalent viruses are Alfalfa mosaic virus and White clover mosaic virus in pasture legumes and Cocksfoot mottle virus, Ryegrass mosaic virus and Barley yellow dwarf virus in pasture grasses. Lucerne Australian latent virus is restricted to the North Island and Red clover necrotic mosaic virus is largely restricted to the South Island. These patterns are likely to be dynamic with ongoing changes in weather patterns, land use, the spread of insect vectors and the continuing introduction of viruses and vectors. The existing and potential threats to 12 pasture species are tabulated and the knowledge gaps for each species highlighted. Control of vectors including aphids, eriophyid mites and soil-borne fungi is probably not economic per se but could be an additional benefit of integrated pest management in pasture and cropping systems. The most cost-effective and practical preventative measures are likely to be the use of virus-tested seed to establish new pastures and the incorporation of resistance genes by conventional breeding or by genetic engineering. Finally, recommendations are made for future research for New Zealand, which is also relevant to other temperate regions of the world.

Occurrence of virus infection in seed stocks and 3-year-old pastures of lucerne (Medicago sativa)

2004 ◽  
Vol 55 (7) ◽  
pp. 757 ◽  
Author(s):  
R. A. C. Jones
Keyword(s):  
Virus Infection ◽  
Medicago Sativa ◽  
Mosaic Virus ◽  
Leaf Roll ◽  
Alfalfa Mosaic Virus ◽  
Subterranean Clover ◽  
Yellow Mosaic Virus ◽  
Grain Legume ◽  
Beet Western Yellows Virus ◽  
Turnip Yellows Virus

In tests on seed samples from 26 commercial seed stocks of lucerne (Medicago sativa) to be sown in south-western Australia in 2001, infection with Alfalfa mosaic virus (AMV) was found in 21 and Cucumber mosaic virus (CMV) in 3 of them. Bean yellow mosaic virus (BYMV) and Pea seed-borne mosaic virus (PSbMV) were not detected in any. Incidences of infection within individual affected seed samples were 0.1–4% (AMV) and 0.1–0.3% (CMV), and the infected seed stocks were from 3 (CMV) and at least 11 (AMV) different lucerne cultivars. In a survey of 31 three-year-old lucerne pastures in the same region in 2001, in randomly collected samples, AMV was found in 30 and luteovirus infection in 11 pastures. Pastures in high, medium, and low rainfall zones were all infected. Incidences of AMV within individual infected pastures were high, with 50–98% of plants infected in 20 of them and only 3 having <10% infection, but luteovirus incidences were only 1–5%. In addition to various cultivar mixtures, at least 8 (AMV) and 3 (luteoviruses) different individual lucerne cultivars were infected. When the species of luteovirus present were identified, they were Bean leaf roll virus, Beet western yellows virus ( = Turnip yellows virus), or Subterranean clover red leaf virus ( = Soybean dwarf virus). CMV and legume-infecting potyviruses (BYMV, PSbMV, and Clover yellow vein virus) were not detected in any of the lucerne samples. Acyrthosiphon kondoi infestation was common in the samples collected, and A. pisum and Aphis craccivora were also found. Widespread infection in lucerne stands, and their frequent colonisation by aphid vectors, are cause for concern not only because of virus-induced production losses in lucerne itself but also because they provide virus infection reservoirs for spread to nearby grain legume crops and annual legume pastures.

scholarly journals The virus infection of South-Hungarian corn fields

2011 ◽  
pp. 52-55
Author(s):  
Melinda Apró ◽  
Mária Papp ◽  
Eszter Cseh ◽  
Richard Gáborjányi ◽  
József Horváth ◽  
...  
Keyword(s):  
Virus Infection ◽  
Mosaic Virus ◽  
Barley Yellow Dwarf Virus ◽  
Brome Mosaic Virus ◽  
Yellow Dwarf ◽  
Dwarf Virus ◽  
Virus Diseases ◽  
Barley Yellow Dwarf ◽  
Yellow Dwarf Virus ◽  
Das Elisa

The past years cereal diseases, including the virus diseases have been increased in Hungary as well as worldwide. The aim of our work was to survey the virus infection of South Hungarian wheat fields. Leaf samples were collected in Szeged at the experimental farm of Cereal Research Nonprofit Co., in April and Junes of 2009 and 2010. DAS ELISA tests were carried out using Loewe antisera of Brome mosaic virus (BMV), Barley yellow dwarf virus (BYDV), Barley stripe mosaic virus (BSMV), Brome streak mosaic virus (BStMV), Wheat dwarf virus (WDV), and Wheat streak mosaic virus (WSMV) and measured with Labsystem Multiscan RC Elisa reader at 405nm. In the samples of 2009 the Wheat dwarf and Wheat streak mosaic viruses were dominated. It was also significant the appearance of the. Barley yellow dwarf virus. 2010. was favourable for the spread of the virus vectors, therefore the incidence of virus diseases increased.

THESIS SUMMARY STUDIES OF ALFALFA MOSAIC VIRUS AND SUBTERRANEAN CLOVER RED LEAF VIRUS

1979 ◽  
pp. 163-164
Author(s):  
P.B. Teh
Keyword(s):  
Mosaic Virus ◽  
Alfalfa Mosaic Virus ◽  
Subterranean Clover ◽  
Test Plant ◽  
Transmission Frequency ◽  
Virus Source ◽  
Leaf Virus

AMV was shown to be transmitted by sap, aphids and through lucerne seed, but not by Cuscuta. Virus source and test plant influenced transmission frequency. Sap-inoculation tests showed that 20 species of plants were susceptible to this virus. Thirteen species of plants from the fields where AMV had been detected were tested but only three were found to be infected with the virus.

scholarly journals Identification, Characterization, and Molecular Detection of Alfalfa mosaic virus in Potato

2006 ◽  
Vol 96 (11) ◽  
pp. 1237-1242 ◽  
Author(s):  
H. Xu ◽  
J. Nie
Keyword(s):  
Mosaic Virus ◽  
Gene Sequence ◽  
Alfalfa Mosaic Virus ◽  
Enzyme Linked Immunosorbent Assay ◽  
Polymorphism Analysis ◽  
Rt Pcr ◽  
Potato Leaf ◽  
Simple Method ◽  
Cp Gene ◽  
Nucleotide Sequence Alignment

Alfalfa mosaic virus (AMV) was detected in potato fields in several provinces in Canada and characterized by bioassay, enzyme-linked immunosorbent assay, and reverse-transcription polymerase chain reaction (RT-PCR). The identity of eight Canadian potato AMV isolates was confirmed by sequence analysis of their coat protein (CP) gene. Sequence and phylogenetic analysis indicated that these eight AMV potato isolates fell into one strain group, whereas a slight difference between Ca175 and the other Canadian AMV isolates was revealed. The Canadian AMV isolates, except Ca175, clustered together among other strains based on alignment of the CP gene sequence. To detect the virus, a pair of primers, AMV-F and AMV-R, specific to the AMV CP gene, was designed based on the nucleotide sequence alignment of known AMV strains. Evaluations showed that RT-PCR using this primer set was specific and sensitive for detecting AMV in potato leaf and tuber samples. AMV RNAs were easily detected in composite samples of 400 to 800 potato leaves or 200 to 400 tubers. Restriction analysis of PCR amplicons with SacI was a simple method for the confirmation of PCR tests. Thus, RT-PCR followed by restriction fragment length polymorphism analysis may be a useful approach for screening potato samples on a large scale for the presence of AMV.

scholarly journals The effect of dairyshed effluent irrigation on the occurrence of plant pathogenic Pythium species in pasture

2000 ◽  
Vol 53 ◽  
pp. 436-440 ◽  
Author(s):  
N.W. Waipara ◽  
S.K. Hawkins
Keyword(s):  
Perennial Ryegrass ◽  
White Clover ◽  
Subterranean Clover ◽  
Preliminary Survey ◽  
Pythium Species ◽  
Effluent Irrigation ◽  
Pathogenicity Tests ◽  
Roots In Vitro

A preliminary survey of pastures sprayirrigated with dairyshed effluent revealed a significant increase in the population of plant pathogenic Pythium species isolated from both soil and roots In vitro pathogenicity tests showed the majority of these isolates to be pathogenic when inoculated onto the seedlings of white clover subterranean clover and perennial ryegrass although both clover species were more susceptible to Pythiuminduced disease than ryegrass

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