A
ProMED-mail post
ProMED-mail is a program of the
International Society for Infectious Diseases
A ProMED-mail post
<http://www.promedmail.org>
ProMED-mail is a program of the
International Society for Infectious Diseases <http://www.isid.org>
Date: 18 September 2008
Source: ABC News (Australian Broadcasting Corporation) [edited]
<http://www.abc.net.au/news/stories/2008/09/18/2368070.htm>
Wheat disease making comeback
One of Australia's earliest wheat diseases is re-emerging on the
Eyre Peninsula. Flag Smut was first described in 1868 with the
fungus producing grey-black lines of spores. South Australian
Research and Development Institute [SARDI] pathologist Dr Hugh
Wallwork says the fungus is being detected in crops near Cowell
and Cleve.
Dr Wallwork says traditionally the fungus has been controlled by
the use of treated seed. "In the early part of the century it
was the most damaging disease of wheat ... it really is a
disease that is completely controlled with good, effective use
of seed treatments,"
he said. "The problem we've had this year [2008] is that because
of the drought and costs of inputs, people have been cutting
back on using some seed treatments."
--
Communicated by:
ProMED-mail
<promed@promedmail.org>
[Flag smut of wheat is caused by the fungus _Urocystis
agropyri_. The disease is known to infect wheat and many grass
species but the
strain(s) that affect wheat are specific to wheat. It occurs in
some European countries, Australia, Canada and the USA. Since
susceptibility varies with wheat cultivars the disease may not
cause major yield losses, but it can have a serious impact on
export trade.
Many nations have quarantine restrictions prohibiting the
importation of wheat products from countries with the disease.
Affected plants are severely stunted. Excessive tillering is
common and often the ears fail to emerge, remaining within the
boot. Plants show long dark grey to black streaks on the leaf
blades and leaf sheaths. The streaks eventually erupt so leaves
become ragged and the black spores are exposed giving the plant
an appearance of being covered in soot. Spores are wind
dispersed and can drop onto the soil where they are very
persistent surviving up to 4 years. Disease management may
include cultural practices, but systemic chemical seed treatment
is the most effective means of controlling the disease.
The re-emergence of this disease in South Australia shows the
importance of retaining disease management practices despite
difficult economic circumstances.
Maps
Australia:
<http://www.ga.gov.au/image_cache/GA4073.jpg>
South Australia:
<http://www.ozhorizons.com.au/sa/map.htm>
Pictures
Wheat flag smut symptoms:
<http://www.hgca.com/hgca/wde/IMAGES/flagsmut2.JPG>
(leaf), <http://www.fao.org/docrep/006/y4011e/y4011e19.jpg>
(leaf), <http://www.fao.org/docrep/006/y4011e/y4011e18.jpg>
(whole plant), and <http://www.fao.org/docrep/006/y4011e/y4011e17.jpg>
(ears) Microscopy of _U. agropyri_ spores:
<http://www.ipm.uiuc.edu/diseases/series400/rpd409/409-4.gif>
Links
Information on wheat flag smut:
<http://pnw-ag.wsu.edu/smallgrains/Flag%20smut.html> and <http://www.hgca.com/hgca/wde/diseases/Flag%20smut/Flaghost.html>
Flag smut life cycle:
<http://www.agric.wa.gov.au/ikmp/images/f02787b.gif>
_U. agropyri_ taxonomy:
<http://www.indexfungorum.org/Names/NamesRecord.asp?RecordID=340754>
SARDI:
<http://www.sardi.sa.gov.au>.
- Mod.DHA] |
|
