REPORTS of early infections of stripe rust in Victorian and New South Wales wheat crops have prompted calls from experts for growers to review their variety ratings and monitor crops for signs of the disease.
A new strain of stripe rust first detected in the southern region in 2018, which has increased virulence on wheat varieties such as DS Bennett and LR Trojan, has been the cause of many of the reported rust outbreaks.
Agriculture Victoria senior research scientist, Grant Hollaway, said the new strain was also showing increased virulence on durum wheat varieties including DBA Spes, DBA Lillaroi, DBA Vittaroi and EGA Bellaroi.
“We have not had too many reports of rust in recent years due to the drier conditions, but this year we are seeing it earlier than normal in areas which have had a wet start,” Dr Hollaway said.
“However, other grain growing areas need to be on high alert too because stripe rust reproduces and spreads by spores, which are wind-blown and can travel hundreds of kilometres.
“This means we are likely to see it elsewhere this year.”
Dr Hollaway encouraged growers and advisers to adopt a three-step approach in assessing stripe rust infections.
- Review crop variety ratings using a current disease guide, not last year’s.
- Monitor crops closely.
- Download the new StripeRustWM app to support decision making regarding management options.
Dr Hollaway said StripeRustWM, which was developed with the support of the Grains Research and Development Corporation (GRDC), would give growers and advisers more confidence in decisions about whether to spray.
“StripeRustWM is a powerful tool which estimates potential losses using information including variety resistance rating, plant growth stage, fungicide history, presence of rust either within the crop or in the district and climatic conditions,” he said.
“The app compares expected yield, predicted loss to stripe rust and anticipated net return for the cases where fungicide is not applied, is applied once, or is applied twice.”
Dr Hollaway said stripe rust was a difficult disease to predict as it was highly influenced by seasonal conditions, which the app took into account.
“By reviewing variety ratings, monitoring crops closely and using the StripeRustWM app, growers and advisers will be able to understand what their risk profile is and plan appropriately,” he said.
The StripeRustWM app is available free for iPads and Android tablets from the Apple App or Google Play Stores. Search for “StripeRustWM”.