October 30, 2005
From: Ground Cover, Issue 57, August/September 2005 [edited] <http://www.grdc.com.au/growers/gc/gc57/cerealrust.htm>

(Professor Robert F. Park and Dr. Colin R. Wellings (Dr. Wellings is on assignment from NSW Primary Industries), University of Sydney Plant Breeding Institute, Cobbitty)

Rust diseases like damp conditions; it is often said that "good cropping years are good rust years." Conditions during the summer preceding a cropping period can also be important in determining the potential for a rusty year.

The 2005 cropping season began with dry conditions in most of eastern Australia and wetter conditions in the west. The expectation could therefore be for rust in the west and little rust in the east. Oddly, several recordings of stripe rust and leaf rust have already been made in the east, but there have been no reports of rust in Western Australia to date.

Wheat stripe rust in Eastern Australia

The 1st confirmed sample of wheat stripe rust [WSR] in 2005 was collected from a Whistler crop at Tarcutta (60 km east of Wagga Wagga in the southwestern slopes of NSW) in the last week of May 2005. This represents a very early report of WSR rust for the 2005 winter crop season. In comparison, the 1st confirmed report in 2004 was collected from a Diamondbird crop in early August 2005. This crop was considered to have become infected from a nearby Whistler field that was sown much earlier in 2004. The Tarcutta field of Whistler was sown on February 2005 rain, and was intended for early grazing. The extent of early sowings of Whistler is unclear, but we presume that those that were established in February and have survived the dry autumn period may be potential sources of inoculum for main season plantings.

2 further reports of stripe rust from eastern Australia were received in late June 2005, the 1st of which came from Grenfell (southern New South Wales) on cv. Wylah. Infection hot spots were evident in the field. The crop was sown on "a fluke storm" in late April 2005. The 2nd report, yet to be confirmed, was from a trial site at Cowra on cv. EGA Gregory, sown in early April 2005. Although early crops are relatively rare in the east in 2005, these sightings should give cause to monitor carefully those crops that have established well.
Late plantings will likely predominate in the east and, depending on the levels of WSR development in early planted fields, may come under pressure in late winter or early spring. However, with just 2 confirmed WSR samples to date, it is far too early to predict epidemic development.

Wheat leaf rust in Eastern Australia

Leaf rust samples were received from Cooma (Monaro region of southern NSW) on 18 May 2005 on cvs. Tennant and Mackellar, which are both long-season winter wheats suitable for grazing and grain recovery. In contrast, the 1st leaf rust samples in 2004 were received in early August 2005. The pathotype of rust responsible was 1st detected from Mackellar wheat in October 2004, and appears to be new. Work is under way to characterize this pathotype in more detail.

Rust samples

This alert should serve to remind cooperators to be aware of the possibility of rust infections in commercial fields, and to be actively looking for signs of infection. Cereal rust samples should be collected when leaves are dry and showing evidence of rust infection. Several leaves can be posted in a paper envelope (no plastic wrapping), including variety details (if known), location of the sample and contact details for correspondence.

Samples can be posted to: Australian Cereal Rust Survey Plant Breeding Institute Private Bag 11 Camden NSW 2570.

--
ProMED-mail
<promed@promedmail.org>

[In 2004, wheat stripe rust [WSR] (caused by _Puccinia striiformis_) reduced yields and grain quality of wheat crops in northern New South Wales and necessitated widespread application of foliar fungicides.
Although WSR was detected in Queensland in late September, it was much less severe than in New South Wales. The "WA pathotype" (134E16A+) was the dominant strain in 2004. 1st detected in Western Australia in 2002, this pathotype is now dominant across Australia and is more virulent on most northern wheat cultivars than its predecessors.

The widespread occurrence of stripe rust in 2004 and its probable survival in the region over summer indicate the disease is likely to develop again during the 2005 season. And it could be more severe in Queensland this year, especially if the epidemic begins early.

Links:
<http://www.seedquest.com/News/releases/2005/august/13326.htm>
<http://crops.confex.com/crops/2005am/techprogram/P4916.HTM>
<http://www.grdc.com.au/growers/as/stripe_rust3.htm>
<http://www.dpi.qld.gov.au/fieldcrops/17139.html>
- Mod.DH]

[see also in the archive:
Wheat stripe rust - USA (FL) 20050601.1521 Wheat diseases - India 20050615.1683
2004
Wheat stripe rust - China 20040429.1191
Wheat stripe rust - Australia (NSW): alert 20040810.2215 Wheat stripe rust - Australia (NSW) 20040928.2683
2003
Wheat streak mosaic - Australia (04) 20030511.1172 Wheat stripe rust, first report - USA (Florida) 20030516.1220 Wheat stripe rust - Australia (WA) 20030624.1553 Wheat stripe rust, new strains - Australia (SA) 20030930.2465
2002
Wheat stripe rust - Australia (Western): alert 20020831.5198
2001
Wheat stripe rust - USA (Great Plains) 20010715.1366 Wheat stripe rust - USA (Central) 20010629.1236 2000
Wheat stem rust in resistant wheat lines - Uganda (02) 20000713.1162 Leaf rust, wheat - Australia 20001215.2187
1999
Stripe rust, barley - Australia (Victoria & NSW) 19991116.2043]