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Stem rust found in oat volunteers in Williams

A close up photo of stem rust on Yitpi wheat plants in the paddock.

Stem rust on Yitpi wheat. Photo courtesy of: Peter Mangano (formerly DAFWA).

Brett Jenkinson (Elders) has found stem rust in oat volunteers in the Williams shire. Five plants were found infected. The oats are at the stem elongation stage.

Plant pathologist Geoff Thomas says that oat stem rust survives on both domestic and wild oats and is favoured by moist warm (18-30°C) weather. So in years like this where autumn rains have generated green bridge regrowth, growers might see stem rust in crop or wild oat regrowth prior to seeding.

Stem rust of oats attacks only oats and wild oats and will not infect barley or wheat. It can cause major yield loss in forage oat crops grown for seed or hay production. Spores are windborne and can spread overlarge distances through the air.

Geoff suggests that the presence of rust infected regrowth is a timely warning of the risk to oat crops from rust this season. Similarly, this is also a warning of potential risk for all cereal rusts in regions with significant green bridge leading into seeding.

It is important that samples of all rusts are sent for pathotype testing. Infected leaf samples should be mailed in paper envelopes (do not use plastic wrapping or plastic lined packages) along with your details and collection information (location, variety etc.) directly to the Australian Cereal Rust Survey, Plant Breeding Institute, Private Bag 4011, Narellan NSW 2567. Free reply paid envelopes can be ordered from Univesity of Sydney.

For further details see the University of Sydney's Cereal Rust website and How to prepare and send samples for dispatch to the Australian Cereal Rust Survey.

For further information including description of symptoms visit the department’s Diagnosing stem rust in oats or Oats leaf diseases pages.

For more information contact Geoff Thomas, Research Officer, South Perth on +61 (0)8 9368 3982.