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May 18, 2003
Wheat Streak Mosaic - Australia (08) 20030521.1246
Source: Australian Broadcasting Corp., Rural News transcript, 19 May 2003[edited]

Restrictions to stop wheat disease spread in Western Australia

Western Australia's Department of Agriculture has put restrictions on seed  movements from eastern Australia, to reduce the spread of wheat streak mosaic virus (WSMV). More than 5000 plant samples have been tested for the virus in WA without trace of WSMV or its vector, the wheat curl mite.

The Department's Rob Delane says the entry or sowing of material from known infected sites will be prohibited this year.

He says there are also implications for the state's breeding and research programs. Materials from high-risk sites or that are linked to infected sites will be excluded from the breeding and research programs. Delane is asking that other private and public researchers do the same.

[Restrictions against movement of WSMV-infected material are probably justified, if for no other reason than to reassure farmers that all possible steps are being taken to prevent entry into Western Australia. The major effort now is to determine whether the virus is present in the standing crop on wheat farms. A second objective should be to determine whether WSMV is seed-transmitted, as it is in some maize cultivars. That might be academic if WSMV and its vector are widespread in wheat production  fields throughout most states in Australia. There is intensive research and development work being undertaken to incorporate resistance to WSMV in wheat. In North America the disease is effectively controlled by eliminating volunteer wheat plants for at least a week prior to seeding the fall crop. For the time being, farmers learn to live with the disease. - Mod.DH]

May 17, 2003
Wheat Streak Mosaic - Australia (07) 20030518.1231
Source: Australian Broadcasting Corp., Rural News transcript 16 May 2003 [edited]

Discoveries of wheat streak virus continue

Wheat streak mosaic has been discovered in the Australian wheat belt for a 10th time.
The NSW Agriculture Centre for Crop Improvement in Tamworth has been placed under quarantine, after tests on a volunteer [self-sown - Mod.JW] plant were found to be positive.
This is the second instance of the disease in the city following confirmation of an earlier outbreak at a private breeding facility last week.

[The disease is widespread in state-run research facilities and in at least one private wheat breeding institute. We are awaiting results of current testing of wheat plants in commercial fields to determine whether WSMV is present on wheat plants in these fields. - Mod.DH]

May 15, 2003
Wheat Streak Mosaic - Australia (06) 20030515.1209
From: Chris Adriaansen <Chris.Adriaansen@dpi.qld.gov.au>
 
Please note that the report in your posting titled "Wheat Streak Mosaic - Australia (05) 20030514.1197" is NOT correct. The Queensland Government Hermitage Research Station, near Warwick, has NOT recorded a positive diagnosis for WSMV.

Detection [in] Queensland remains limited to Leslie Research Centre and Wellcamp Research Station, both near Toowoomba.

This report originated from erroneous media coverage of WSMV, in which journalists appear simply to have missed the word "not" in a media release made by this Department. The original media release
states "WSMV has not been found at the DPI Hermitage Research Station

Chris Adriaansen
A/ General Manager, Plant Health
Animal & Plant Health Service
Queensland Government
Department of Primary Industry
<Chris.Adriaansen@dpi.qld.gov.au>

[I sincerely thank Chris Adriaansen for correcting an erroneous report. - Mod.DH]

May 13, 2003
"Wheat Streak Mosaic - Australia (05) 20030514.1197"
From: ProMED-mail<promed@promedmail.org>
Source: Queensland Government, Department of Primary Industries News, Australia, 12 May 2003 [edited]

Wheat virus search moves on to farms

The Department of Primary Industries (DPI) is seeking the assistance of the grains industry as it moves its search for wheat streak mosaic virus (WSMV) from its research centres to other grain industry sites.

General Manager of Plant Health, Chris Adriaansen, said that extending the surveillance program was a critical step in DPI's effort to establish the extent of the virus and its vector, the leaf curl mite.

Adriaansen said that initial containment measures at the Leslie Research Centre and Wellcamp Research Station were completed and results of samples taken at other DPI research stations are expected shortly.

He further stated that other parts of the grain industry [will be sampled and tested?], including off-station sites where trials were planted last year, especially at areas where WSMV or its mite vector may have survived last year's winter cereal crop, due to the continuing presence of green host plants.

The decision to expand the survey area was taken by the national management group overseeing the Australia-wide response program.

"Fortunately, there is little crop in the ground at this time of the year, so this surveillance program should be completed quite quickly."

Adriaansen said DPI had begun contacting farmers about the surveillance program, which would allow it to gain a rapid assessment of the extent of the virus over a wide range of localities and environmental conditions. He also said that DPI was liaising extensively with John Agnew, the Director of AgForce Grains, which had given its support to the surveillance program. The extended surveillance was an important next step in the containment program.

On-property surveillance across the Queensland grain belt would commence early this week following contact with producers and others in the grains industry.

[To date, the search for wheat streak has concentrated on known plantings of research materials in state-run institutes and private breeding stations. The decision to survey for wheat streak mosaic in farmer's fields is a major step in determining whether WSMV is present in commercial acreages. The disease has been reported in all states except Western Australia. The controversy over whether WSMV is seed-transmitted in wheat remains unclear as does [seed's] involvement in perpetuating the virus. It is transmitted via seed in certain maize cultivars at rates of 0.01- 0.02 percent; I had earlier indicated it was 0.1- 0.2 percent. - Mod.DH]

May 12, 2003
Wheat Streak Mosaic - Australia (05) 20030514.1197
Source:Australian Broadcasting Corp., 12 May 2003 [edited]

Toll mounts for wheat streak mosaic

Wheat plants infected with wheat streak mosaic virus (WSMV) have been found at 2 more sites in Australia. Tests revealed that WSMV was detected at a private plant breeding nursery at Bendigo, in central Victoria, and at the government-run Hermitage Research Station, near Warwick in southeast
Queensland. [see above May 15, 2003 - this is not correct (SeedQuest)]

Western Australia is now the only mainland state still free of WSMV.

May 10, 2003
Wheat Streak Mosaic - Australia (04) 20030511.1172
Source: Australian Biotechnology News, 6 May 2003 [edited]

Wheat streak mosaic may not pose much of a risk to Australia's cereal crops after all, according to a leading plant scientist at Adelaide University and research director of the Cooperative Research Centre for Molecular Plant Breeding.

Prof Peter Langridge told Australian Biotechnology News that media reports claiming the virus could potentially damage up to 90 percent of Australia's wheat crops were unsubstantiated. In fact, he said, the virus had never even been considered a serious threat to Australia's grains industry.

A quarantine that has been enforced by Plant Health Australia and South Australia's Department of Primary Industries means that not even nucleic acid can be sent out of the facilities for the time being. And researchers, particularly the students among them, are worried about the possibility of having to destroy the plants they have spent months, if not years, developing.

Tragically for CSIRO, it may yet turn out that the virus has been in Australia for years, without causing major damage to Australia's cereal crops and breeding programs. One Waite wheat breeder said similar symptoms had been present in wheat plants in Australia for more than 10 years.

Australia has several programs aimed at developing resistance to potential pathogens not yet found in Australia, according to Langridge. In general, these programs are aimed at developing varieties with resistance genes to serious diseases, using molecular markers to select for resistance genes. Thus plants do not need to be exposed to the pathogen until relatively late in the process, and are usually sent overseas to be tested by breeding partners, thus avoiding the need to bring the infectious agent into Australia at all.

So far, the strategy has been a good one, and has worked for every pathogen that plant geneticists have targeted. But wheat streak mosaic has never been regarded as a potential threat to Australian crops to justify an active breeding program for resistance, said Langridge.

Instead, the focus has been on more devastating diseases including stripe rust in barley, karnal bunt, and the Russian wheat aphid. According to Langridge, there is material in the pipeline that could be released to growers within 1 or 2 years. If the virus becomes a serious threat to Australia's grain industry, new resistant cereal varieties could probably be developed within about 5 years.

Another strike against the virus, according to Langridge, is the difference in the growing environment between Australia and the countries which do have a problem with the virus, which includes North America and parts of Northern Europe. Factors involved include climate differences, as well as
crop planting and rotation practices. Langridge says that the diseases faced in Australia are very different from those in other parts of the world.

[I regard this piece as a balanced account of the current situation regarding the outbreak of wheat streak mosaic in Australia. - Mod.DH]

May 7, 2003

Source: Australian Broadcasting Corp., Rural News transcript, 7 May 2003 [edited]

Wheat virus found on private farm

Testing for wheat streak mosaic virus (WSMV) is about to start in commercial cropping areas, following the first confirmation of the disease on a private farm in South Australia.

So far the virus has been identified on the farm and 8 research facilities across the ACT, New South Wales, Queensland, Victoria, and South Australia.

The wheat curl mite, which carries the virus, lives in host plants like cereal crops or grasses before it transfers the virus to wheat.

The country's chief plant protection officer, Dr Graeme Hamilton, says authorities will begin testing in irrigated regions or areas where there's been some recent rain. Pathologists are directing attention to summer maize and sorghum crops or volunteer cereal crops that could harbor the mite vector that transmits WSMV to new wheat plantings.

The affected commercial farm is an irrigated property near Bordertown in South Australia.

The discovery has forced the South Australian Farmers Federation (SAFF) to reconsider its policy of eradicating the virus.

Chairman of the Federation's Grains Council, Greg Schulz, says the evidence is building that the virus may have been in Australia for a long time, but that mightn't be all bad news. "If the disease turns out to be widespread, I guess what it demonstrates is that the disease has been having minimal impact -- if it has been out there for a while."

WSMV has also been confirmed for the first time in New South Wales. Dr Lindsay Cook, who heads up the plant industry division for NSW Agriculture, said the virus had been found in a glasshouse, in a private breeding facility in Tamworth.

The Division sampled its breeding programme at Wagga, the first lot of samples sent being negative. A second series of samples is being tested, but no WSMV has been found to date.

[Wheat streak mosaic has now been reported from 5 jurisdictions in Australia. It appears that wheat streak mosaic has been in the background for some time in Australia. Matthew Cromey of the NZ Ministry of Food and Forestry (MAF) reports that WSMV has not been recorded in New Zealand but
apparently has not been specifically tested for. The mite vector is present in New Zealand, but MAF has no record of the virus in the country.- Mod.DH]

May 6, 2003
Wheat Streak Mosaic - Australia (03) 20030508.1146
Source: Australian Broadcasting Corp., transcript May 6 2003 [edited]

Wheat streak mosaic virus mounts - Victorian plot confirmed

Wheat streak mosaic virus (WSMV) has been confirmed in a research plot in western Victoria, in the heart of the state's key grain-growing regions of the Wimmera and Mallee. The outbreak is being managed by the Victorian Institute for Dryland Agriculture. As yet no decision has been made on
whether to destroy plants at the site.

The 600-hectare site just south west of Horsham is the latest trial site to be quarantined. No susceptible cereal or plant material can now be removed from the site. Australia's plant protection officers will meet today in Canberra to decide what action can be taken, both at Horsham and nationally.

It's believed they're discussing whether Australia's virus-free status has come to an end, after discoveries of the virus in the ACT, Queensland, and South Australia.

Testing in the wake of Queensland's first detection of WSMV in research plots has not revealed any further cases at the Leslie Research Centre, where 2 plants tested positive last week. It's expected other Department of Primary Industry research stations in the state's south will be checked for the disease later this week.

The Australian Wheat Board (AWB), Australia's monopoly wheat exporter, is playing down the impact of the virus on its sales to overseas customers. AWB says the virus is only transported on live plant matter, not grain, so it's not an export risk. Spokesman Peter McBride says that the disease is manageable and that the Australian farming community will be able to manage the disease should it spread to broad acre farming.

April 29, 2003
Wheat Streak Mosaic - Australia (02) 20030508.1143

Wheat streak mosaic tritimovirus found in second site in Australia

In a blow for the country's wheat industry, wheat streak mosaic tritimovirus (WSMV) has been discovered in a second site, at the Waite Institute, South Australia's major research facility.

14 research sites around Australia were placed in quarantine when the virus was detected for the first time in CSIRO research sites in Canberra before Easter. That discovery prompted the destruction of 30 000 cereal plants, and set back research by 4 years.

David Cartwright, Primary Industries and Resources South Australia, says no plants have been destroyed at the Waite as yet, but there's been a total lock-down of research facilities at the site, which includes horticulture and grain plots.

Cartwright says questions have been raised over whether WSMV has been in South Australia for some time. He said that there were suspicions in the mid-1990's, but results of tests in Australia and overseas at that time could not confirm presence of the virus.

A national survey is underway to find out how far WSMV has spread and whether the disease is present at research and nursery facilities.

[This is the second known outbreak of WSMV in Australia. It infects most or all varieties of wheat (Triticum aestivum), oats (Avena sativa), barley (Hordeum vulgare), and rye (Secale cereale), and some varieties of maize (Zea mays) and millets (Panicum, Setaria, and Echinochloa spp.). Of considerable interest is the fact that it also infects many wild grass species. The suspicion that WSMV may have been in Australia for some time is of concern to farmers. Surveys should be made on wild grasses growing near cereal production fields to assess their role as hosts from which the virus is dispersed by the mite vector. - Mod.DH]

April 17, 2003
From: ProMED-mail<promed@promedmail.org>
Source: The Age, 17 April 2003 [edited]

Killer virus hits CSIRO research

The CSIRO [Australia's Commonwealth Scientific and Industrial Research Organisation, a non-governmental entity] will destroy all cereal plants at 23 of its research centres in Canberra today in an
effort to eradicate a killer wheat virus discovered on site. In a devastating blow to the research body's AUD 15 million [USD 9 198 600] cereal program, about 7000 plants will be destroyed, including
barley, oats, and corn plants.

Cases of wheat streak mosaic tritimovirus infection were confirmed at the CSIRO's Black Mountain and Ginnindeera centres earlier [in April 2003], and wheat plants have since been destroyed.

A consultative committee on plant diseases met yesterday to decide whether other cereal crops at the CSIRO should also be destroyed. CSIRO volunteered to destroy all the plants, representing 20 percent
of its research effort. The chief of CSIRO Plant Industry, Jim Peacock, said it was the responsible thing to do.

It is believed to be the first confirmed case in Australia of the virus, which is prevalent in North America, Russia, and Eastern Europe.

[Byline: Orietta Guerrera]

[Wheat streak can cause complete crop failure following heavy infection. The virus is transmitted by the wheat curl mite (Eriophyes tulipae). Mite larvae acquire the virus by feeding on infected plants and retain the ability to transmit virus for about a week after acquisition. Windborne viruliferous mites spread the virus to neighboring plants. A key management strategy is to prevent volunteer wheat from growing in the interval between harvested spring wheat crops and fall-sown winter wheat. A key question is how the virus reached Australia. To my knowledge, WSMV is not seed-transmitted in wheat but is seed-transmitted in some maize cultivars at low levels (0.1 to 0.2 percent). Do any of our readers have information on this point?- Mod.DH]