THE Grain Research and Development Corporation has released up-to-date disease ratings from its National Variety Trials.

Growers can now utilise the data to assess different varieties’ susceptibility and resistance to stripe rust along with other common wheat diseases.

New South Wales Department of Primary Industries senior plant pathologist Steven Simpfendorfer said a main factor to early management was variety selection — either choosing to plant a more resistant variety to minimise disease risk altogether or being prepared to implement early management strategies if a susceptible variety is grown.

 “Last year taught us a lot about risk versus reward when growing susceptible stripe rust varieties,” he said.

“If growers opt to plant susceptible varieties because they’re chasing the reward of a perceived high yield, they’ll need to be right on top of management.

“Fungicides are effective if applications are well timed but last year, when we saw unavoidable 10-day delays in spraying because of weather conditions, growers faced significant yield loss of 30-40 per cent in susceptible varieties because of that heightened susceptibility to stripe rust infection.”

Dr Simpfendorfer said every little jump in resistance level makes a significant difference in the paddock — so growers will need to decide what they want to prioritise and make informed decisions based on reliable data like the NVT’s disease ratings.

“This could be things like making grazing decisions during the summer fallow period — if growers want to keep some green pick of wheat volunteers in their paddocks for sheep, then they should be wary about letting their susceptible varieties get away, because they’ll support a bigger green bridge risk than volunteers of more resistant varieties,” he said.

“If they’re choosing to grow a susceptible variety to stripe rust to chase yield, or because that’s what they have seed for, then they could be putting measures in place to ensure they can implement early management strategies, such as having adequate access to foliar fungicides and considering upfront fungicide options like Flutriafol.”

GRDC manager of NVT systems Neale Sutton said the NVT disease program provides annual ratings based on in-field assessments of disease from multiple trials across the country.

“When considering this year’s anticipated stripe rust risk, we want to encourage growers to use our nationally standardised system to understand how their chosen varieties could perform in their region against high disease pressure,” he said.

“GRDC has invested strongly in the NVT program, which supplies growers with independent data that can help them make decisions to strengthen their profitability and management options.”

Growers can access the latest Stripe Rust disease ratings via GRDC’s NVT website.