.

[1] Stripe rust, wheat - Australia (South Australia)
[2] Stripe rust, wheat, _Wheat streak mosaic virus_ - Australia (Western Australia)

******
[1] Stripe rust, wheat - Australia (South Australia)
Date: Mon 27 Aug 2007
Source: Australian Broadcasting Corporation News [edited] <http://www.abc.net.au/news/stories/2007/08/27/2015806.htm>

A small hot spot of stripe rust has been found in wheat on a Mallee property south of Taplan in southeastern South Australia.

Local agronomists are urging farmers to monitor their wheat crops, particularly susceptible varieties such as Wyalkatchem, Krichauff, and Machete.

Peter Treloar from Rural Solutions SA says the infection is surprising, given the recent dry conditions. "The new strain is certainly more aggressive, gets termed the WA strain, seems to be more aggressive as far as a bigger window for infection in regards to temperature. I'm surprised, it's being so dry, it must have just been a lucky shower and [the fungus] just happened to be there and got the conditions right to infect," he said.

--
Communicated by:
J. Allan Dodds
Former ProMED-mail plant disease moderator <dodds@ucr.edu>

******
[2] Stripe rust, wheat, _Wheat streak mosaic virus_ - Australia (Western Australia)
Date: Wed 22 Aug 2007
Source: Australian Broadcasting Corporation News [edited] <http://www.abc.net.au/news/stories/2007/08/22/2011699.htm>

Western Australian farmers are being urged to look out for signs of stripe rust and _Wheat streak mosaic virus_ (WSMV) in the wheatbelt.

Stripe rust has been found in a wheat crop on a property south of Cunderdin in the state's southwest, while another disease known as WSMV was found in a crop south of Koorda.

Plant pathologist with the Department of Agriculture and Food, Geoff Thomas, says the discovery of stripe rust is still early enough for the disease to cause significant crop damage.

"[It is] very important that farmers are out having a look at their crops in relation to crop diseases, obviously, particularly in terms of a disease like stripe rust," he said. "The earlier that it can be identified and some control measures such as fungicide application taken, the lesser chance of crop damage occurring."

--
Communicated by:
J. Allan Dodds
Former ProMED-mail plant disease moderator
<dodds@ucr.edu>

Wheat stripe rust

Wheat stripe rust (also called yellow rust) is caused by the fungus _Puccinia striiformis_ var. _striiformis_ and occurs worldwide mostly in cooler climates. It causes yellow leaf stripes, stunting of plants, and reduced grain number and size on developing heads. Yield losses may vary from 40 up to 100 percent. It affects wheat, some
barley varieties, triticale, and a number of grass species. Spores are wind dispersed in several cycles during the cropping season. The fungus needs living plants to survive between seasons, it cannot survive on seed, stubble, or in soil. Volunteer plants may generate a "green bridge" providing inoculum to infect new crops. Disease management strategies include fungicide applications and control of volunteer wheat plants.

Since the fungus interferes with seed development, infection early in the crop cycle is more damaging than infection after seed fill has concluded. Early discovery of infection at any stage of the crop cycle is important so action can be taken to limit the spread of the pathogen as well as build-up of inoculum.

Stripe rust was introduced to eastern Australia in 1979, most likely from Europe. A number of strains with increased virulence on more wheat varieties developed over time. These strains did not spread to Western Australia. The pathogen was then introduced again to Western Australia in 2002, probably from the USA. The WA strain had spread to eastern Australia by 2003, where it is now dominant. The Australian Cereal Rust Control Program monitors the occurrence of cereal rust pathotypes each year and in 2003, for example, 6 pathotypes of stripe rust were identified throughout Australia.

Wheat streak mosaic virus

Wheat streak mosaic virus (WSMV; genus _Tritimovirus_, family _Potyviridae_) is prevalent in North America, Russia, Eastern Europe, and has recently been reported from Australia (2003) and Argentina. It is spread by the wheat curl mite _Aceria tulipae_. Larvae acquire the virus by feeding on infected plants and remain infectious for
approximately a week. The virus is not transmitted congenitally to the progeny of the vector. WSMV can also be mechanically transmitted and seed transmitted at a very low level. It infects wheat, maize (some cultivars), grasses, and also oats and barley in experimental inoculations. Heavy infection of WSMV can cause complete crop failure in wheat. Control of the mite vector is difficult but disease management may occur by controlling volunteer wheat and grassy weeds to minimise inoculum.

The Mallee is an area characterised by its natural vegetation of small to medium high eucalypt species with multiple trunks.

Maps
Australia:
<http://www.ga.gov.au/image_cache/GA4073.jpg>
South Australia:
<http://www.ozhorizons.com.au/sa/map.htm>
Western Australia:
<http://www.ozhorizons.com.au/wa/map.htm>

Pictures
Stripe rust, wheat leaf symptoms:
<http://www.ars.usda.gov/Main/docs.htm?docid=9918&pf=1&cg_id=0>
_Wheat streak mosaic virus_, leaf symptoms
<http://www2.dpi.qld.gov.au/images/8658.jpg>
Wheat curl mite
<http://www.nwroc.umn.edu/Cropping_Issues/2006/Issue8/wht_curl_mite.jpg>

Links:
Information on wheat stripe rust:
<http://www.ars.usda.gov/Main/docs.htm?docid=9918&pf=1&cg_id=0>  and
<http://www.oznet.k-state.edu/path-ext/factSheets/Wheat/Wheat%20Stripe%20Rust.asp>
_P. striiformis_ taxonomy:
<http://www.indexfungorum.org/Names/NamesRecord.asp?RecordID=427989>
_Wheat streak mosaic virus_ taxonomy and description:
<http://www.ncbi.nlm.nih.gov/ICTVdb/ICTVdB/00.057.0.06.001.htm>
Wheat streak disease information with pictures:
<http://plantpathology.tamu.edu/Texlab/Grains/Wheat/wsmv.html>
Wheat streak disease fact sheet:
<http://www.agric.wa.gov.au/pls/portal30/docs/FOLDER/IKMP/PW/PH/DIS/CER/FS005_2003.PDF>. 
- Mod.DHA]

[see also in the archive:
Fungal diseases, wheat & pulses - Australia (SA) 20070821.2729
Stripe rust, wheat - USA, Australia 20070614.1950
2006
----
Wheat streak virus - USA 20060608.1606
2005
----
Stripe rust, wheat - Australia 20051031.3173
2004
----
Wheat streak mosaic virus - Argentina: 1st report 20040922.2614
Wheat stripe rust - Australia (NSW) 20040928.2683
Wheat stripe rust - Australia (NSW): alert 20040810.2215
2003
----
Wheat stripe rust, new strains - Australia (SA) 20030930.2465
Wheat stripe rust - Australia (WA) 20030624.1553
Wheat streak mosaic, first report - Australia (Canberra) 20030417.0941
2002
----
Wheat stripe rust - Australia (Western): alert 20020831.5198]

The news item on this page is copyright by the organization where it originated - Fair use notice

Other news from this source