July 11, 2012
Western Australian growers with wheat crops susceptible to stem rust should be vigilant in checking crops and spray them early if they find the damaging disease.
Grains Research and Development Corporation (GRDC) supported fungicide trials conducted by the Department of Agriculture and Food (DAFWA) have highlighted the importance of responding early to wheat stem rust in susceptible varieties to minimise losses in yield and grain quality.
DAFWA plant pathologist Kith Jayasena said it was of concern that stem rust had been found in recent weeks in new season barley crops in the Esperance region and earlier this year in barley regrowth in the lower Great Southern region.
“Barley crops – which are a host for wheat stem rust - are unlikely to incur much damage from stem rust,” Dr Jayasena said.
“But the risk is that wheat stem rust can move from barley into susceptible wheat varieties such as Yitpi and Westonia which can incur yield losses of up to 90 per cent if the disease is not controlled.
“Conditions in recent weeks have been conducive for the spread of wheat stem rust, which thrives in warmer weather.”
Dr Jayasena said fungicide trials he conducted in 2011 showed the best economic returns for stem rust control were achieved when two foliar sprays of a registered fungicide were applied – when wheat stem rust first became evident, and three weeks later.
“This strategy, when applied in trials in the high yielding environment of Gibson in the Esperance region, provided yields 56 per cent greater than the unsprayed crop, and economic returns of $399 per hectare – compared with $83/ha from a single fungicide application at the first sign of the disease, and $111/ha for a single spray three weeks after the disease became evident,” Dr Jayasena said.
Associate Professor Colin Wellings (on secondment from the NSW Department of Primary Industries) at the University of Sydney’s Plant Breeding Institute, said suspected rust samples should be posted to the Australian Cereal Rust Control Program’s (ACRCP) Cereal Rust Survey as soon as possible.
“The samples will be important in allowing us to distinguish between the three possible stem rust pathogens affecting barley,” he said.
“One of these – wheat stem rust – will be a potential threat to adjacent wheat crops.”
To post suspected rust samples to PBI, use paper envelopes (do not use plastic wrapping or plastic lined packages). Direct samples, including the sender’s name and email address, to:
Cereal Rust Survey
Plant Breeding Institute
Private Bag 4011
Narellan, NSW 2567
For more information on developing a rust management plan, visit www.rustbust.com.au or contact your local agronomist.
Rust Bust is an initiative of the ACRCP consultative committee, supported by the GRDC.
Information on diseases including rust can also be found at www.grdc.com.au/diseaselinks