WITH harvest underway across the country farmers are finally getting a feel for the amount of damage caused by fungal disease.
Stripe rust in wheat is expected to have caused multi-million dollar yield losses.
Farmers have reported issues with trafficability, meaning sprays could not go out in a timely fashion, have been the major culprit, although even in areas without paddock access problems there are cases of severe infestation.
"We have not yet started wheat but we expect there to be some pretty significant damage," Rankins Springs, NSW, grower Mark Dwyer said.
"It looks like ranging between 10-20 per cent in many cases but there will be paddocks where it potentially could be worse, over 50pc which is going to be tough to swallow given how much money we spent growing the crop this year," Mr Dwyer said.
"The big concern is that once we get into the wheat properly more people will notice that it is worse than previously thought," he said.
The area impacted could cover much of the eastern seaboard.
There are growing concerns in parts of the southern Wimmera, where soil types prevented sprayers getting out in the paddock following the spring rain, will also have pockets where there is in excess of 60pc yield loss.
Traditionally, the upper limits of stripe rust damage are expected to sit at around 15-20pc in Australian cropping systems but research has showed near complete crop decimation in susceptible varieties in years of high disease pressure.
Crop pathologists have said this season has seen extremely high levels of fungal disease due to near perfect conditions for it to breed up.
Agriculture Victoria said it was expecting higher levels of stripe rust damage than normal.
Plant pathologist at Agriculture Victoria Grant Hollaway said difficulties in spraying would have encouraged disease spread.
"Stripe rust control is best achieved by keeping disease levels low; any delays in spray application this year would likely have enabled the disease to spread at a faster rate," Dr Hollaway said.
He said it was expected damage would be most severe in areas where there is not a traditional need for multiple fungicide applications.
Agriculture Victoria is anticipating disease damage will be higher in areas where there is traditionally a higher reliance on fungicides for disease control such as high rainfall zones.
This was backed up by Birchip Cropping Group.
BCG senior manager of extension and communications Kelly Angel said yield losses through the group's catchment varied enormously, with varietal choice critical.
"If there were no fungicides used there could be losses of 50 per cent in susceptible varieties, however where resistant varieties were grown, even without fungicides the losses can be less than five per cent," Ms Angel said.
She said the time of the rust infestation and fungicide application timing were also important in determining the extent of the damage.
She said disease management would be a key focus of BCG's trial results day, held February 24 next year.
Dr Hollaway cautioned growers to think about potentially high levels of disease carry over when making decisions on crop rotations for next year.
"It is important that variety selection for 2023 considers the higher rust risk and the use of up-front fungicides at sowing is considered," he said.
The grower community is pushing for more work into disease management, specifically better varietal resistance.
"We've seen this year what can happen when disease gets in and we can't spray, we are calling for the GRDC (Grains Research and Development Corporation) to invest further into disease research," said Rankins Springs grower Jock Munro.
"Quite a few of us feel that the current research priorities are out of step with what growers want," Mr Munro said.
"We understand disease pressure hasn't been this high for some years but given how much we stand to lose in these potential high yielding years it always has to be a major priority for research," he said.
Ms Angel said along with stripe rust fungal disease in pulses, such as chocolate spot and grey mould have caused heavy yield losses across large areas of the Wimmera, Mallee and North Central.