Australia
July 29, 2010
Stripe rust and leaf rust were found on wheat plant samples collected in early winter from grain growers’ fields by the Grains Research and Development Corporation (GRDC)-supported Plant Breeding Institute (PBI).
Professor Robert Park, University of Sydney PBI, says growers should prepare for possible fungicide support in varieties known to be vulnerable to the rust.
Two stripe rust pathotypes have already been identified including ‘Jackie’ pathotype found in a crop of Endeavour triticale at Laggan, near Crookwell, southern NSW on 10 June.
The grower reports evidence of stripe rust in several triticale varieties.
The second pathotype, “WA Yr17’, was found in two samples from an early sown field of Marombi wheat at Cargo, central west NSW.
“This sample was over 100 kilometres from the triticale sample,” Prof Park said.
“The contrast in pathotype and the distance between these locations confirms that stripe rust survived independently at these locations.”
The ‘WA Yr17’ pathotype was also found in a sample received on 29 June, collected from a Whistler crop growing near Jerilderie in southern NSW.
Prof Park says the second detection indicates the ‘WA Yr17’ pathotype is present early in the season, in contrast to previous seasons, and from widely distant locations.
“These results should be considered an early warning for Yr17 varieties known to be vulnerable to this pathotype, and will serve to remind growers and advisors to carefully monitor crops,” he said.
Other stripe rust samples received, in early July, were from:
- Ellison wheat, Eugowra, central west NSW
- Marombi wheat, Cowra, central west NSW
- Diamondbird wheat, Nagambie, central Victoria
- un-named wheat, Benalla, central Victoria
The wide separation of these samples and the likelihood that the ‘WA Yr17’ pathotype will be found in Ellison and Marombi strengthens calls for careful monitoring of crops across the southern regions of eastern Australia.
Wheat leaf rust has been found in the northern region at Warwick, Queensland. Other samples from southern regions were found to comprise two exotic leaf rust pathotypes, which are now present throughout Victoria, southern and northern NSW, South Australia and Tasmania.
Crown rust of oats is also widespread in eastern Australia following several
years of very low occurrence. Thirty samples have been received since the beginning of April, from oat crops in Queensland and northern NSW, including sites at Toowoomba, Gatton, Texas, Dorrigo and Tenterfield.
“It will be important for advisors and growers to carefully weigh up fungicide options for 2010 in light of these early reports and results from the cereal rust
pathogen survey,” Prof Park said.
“With increasing concerns for anticipated plague locust control measures in late
winter and spring and the potential for cereal rusts to quickly reach damaging levels, there may well be situations arise where competition for resources such as aircraft will demand careful considerations of priorities.”
He said issues to be considered will include:
- timely application of fungicide.
- product choice. Fungicides vary in curative and protectant characteristics, and these are broadly appreciated even if not carefully defined.
- setting crop protection priorities. In situations where resources are limited (product or contractor shortages), consideration will need to be given to applying fungicide to varieties or even areas within a crop that would be expected to have the highest potential returns. Any relaxation in resources will allow second priority varieties and/or cropping areas to be addressed.
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