A
ProMED-mail post
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International Society for Infectious Diseases
A ProMED-mail post
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ProMED-mail is a program of the
International Society for Infectious Diseases <http://www.isid.org>
Date: Wed 6 May 2009
Source: Farmers Weekly Interactive [edited]
<http://www.fwi.co.uk/Articles/2009/05/06/115467/new-yellow-rust-race-threatens-wheat.html>
New yellow rust race threatens wheat
A new race of yellow rust that infects Solstice wheat is being
investigated by NIAB [National Institute of Agricultural
Botany]. Samples taken during the United Kingdom Cereal Pathogen
Virulence Survey (UKCPVS) last season from the variety have been
confirmed as virulent also in seedlings. NIAB is now testing the
isolates on adult plants in the field to determine the level of
susceptibility of Solstice and other varieties to the race.
Solstice was previously resistant to all known yellow rust
races.
Wheat growers also face a resurgence of older yellow rust races,
says NIAB, because of an increasing area of varieties with
yellow rust resistance gene Yr6. "Despite predictions that
yellow rust was unlikely to be a problem because of the cold
winter, outbreaks have been detected in wheat crops particularly
in the high risk areas of the East Midlands and East Anglia,"
says NIAB's Rosemary Bayles. "Reports suggest Robigus and Oakley
are particularly affected." Robigus is extremely susceptible to
a specific race that has dominated the yellow rust population
for several years. But Oakley has remained largely free to date,
so the appearance of the disease may be more of a surprise to
its growers.
But UKCPVS results suggest it is moderately susceptible to a
separate race of yellow rust, which although once quite common,
has become less frequent in recent years. Unlike the "Robigus
race" the types that infect Oakley carry virulence for the
resistance gene Yr6, says Dr Bayles. "Our experience shows that
as a variety becomes more widely grown on farm, yellow rust
races with corresponding virulence rapidly become more common.
We could, therefore, expect to see an increase in Yr6-virulent
races in response to increasing area of Oakley, and this would
account for the increased incidence of the disease in this
variety."
[byline: Mike Abram]
--
communicated by:
ProMED-mail
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[Stripe rust, also called yellow rust, of cereals is caused by
the fungus _Puccinia striiformis_ var. _striiformis_. It causes
yellow leaf stripes and stunting of plants with yield losses of
40 to 100 per cent. It affects wheat, some barley varieties,
triticale, and a number of wild grasses.
Spores are wind dispersed in several cycles during the cropping
season.
Grasses and volunteer crop plants may generate a "green bridge"
providing inoculum for the next crop cycle. Disease management
includes the use of resistant varieties, fungicide applications,
and control of volunteer crops.
Continuous resistance breeding is required to keep ahead of
pathogen adaption. New stripe rust strains with increased
virulence have been reported in recent years from Europe, North
America, Australia, India and are also suspected to emerge in
China. Disease monitoring, such as the UKCPVS mentioned above,
is important to recognise new pathogen strains. In the UK this
has lead to the finding that the recent outbreak of stripe rust
in England and Scotland (ProMED-mail posts 20090417.1452 and
20090424.1543) is due to at least one new fungal strain. The
report above also illustrates the interactive co-evolution of
host and pathogen strains (races) in the field.
Maps of UK:
<http://www.lib.utexas.edu/maps/europe/united_kingdom.gif>
and
<http://healthmap.org/r/008E>
Pictures Stripe rust on wheat leaf:
<http://utextension.tennessee.edu/fieldCrops/wheat/Wheat_photos/Wheat_StripeRust.jpg>
and
<http://www.grdc.com.au/uploads/images/Stripe%20rust%20Colin%20Wellings%20ACRCP.JPG>
Stripe rust on wheat head:
<http://cril.cimmyt.org/gallery/main.php?g2_view=core.DownloadItem&g2_itemId=950&g2_serialNumber=2>
Stripe rust on resistant and susceptible wheat cultivars:
<http://www.oznet.ksu.edu/path-ext/factSheets/wheat/Wheatimages/wheats1.jpg>
Barley with stripe rust:
<http://www.ipmcenters.org/cropprofiles/docs/Graphics/WAbarleyStripeRust.jpg>
Ryegrass with stripe rust:
<http://plant-disease.ippc.orst.edu/plant_images/ryegrass_stripe_rust.jpg>
Links
Information on wheat stripe rust:
<http://pnw-ag.wsu.edu/smallgrains/Stripe%20Rust.html>,
<http://www.ars.usda.gov/Main/docs.htm?docid=9918&pf=1&cg_id=0>,
<http://www.dpi.nsw.gov.au/__data/assets/pdf_file/0006/158964/stripe-rust-in-wheat.pdf>,
and
<http://www.oznet.k-state.edu/path-ext/factSheets/Wheat/Wheat%20Stripe%20Rust.asp>
Stripe rust management:
<http://www.grdc.com.au/uploads/documents/striperustmgt.pdf>
and <http://www.ipm.ucdavis.edu/PMG/r730100511.html>
_P. striiformis_ taxonomy:
<http://www.indexfungorum.org/Names/NamesRecord.asp?RecordID=427989>
NIAB:
<http://www.niab.com/>.
- Mod.DHA]
[see also
in the
archive:
Rust diseases, wheat - UK, Pakistan 20090424.1543 Stripe rust,
wheat - UK 20090417.1452 Stripe rust, wheat - India: new strain
20090329.1216 Wheat rusts - Kenya, India, Australia
20090312.1019 Rust diseases, wheat, mustard - India: (JK)
20090305.0897 Stripe rust, wheat - China 20090208.0579
2008
---
Stripe rust, wheat - Australia (02): (VIC) 20080916.2897 Stripe
rust, wheat - Australia: (QLD, NSW), alert 20080716.2156 Cereal
rusts - Australia: (NSW) 20080624.1945 Wheat stripe rust,
oilseed rape sclerotinia - China 20080408.1297 Stripe rust,
wheat - Denmark: new strains 20080211.0542
2007
---
Stripe rust, wheat - Australia (SA): new strain 20070921.3135
Stripe rust, wheat & wheat streak mosaic - Australia (SA, WA)
20070830.2860 Fungal diseases, wheat & pulses - Australia (SA)
20070821.2729 Ergot & stripe rust, cereals - USA (MT)
20070706.2144 Stripe rust, wheat - USA, Australia 20070614.1950
Wheat stripe rust, wheat - China 20070413.1230 and older items
in the archives] |
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