GRAIN growers need to keep summer weeds and cereal volunteer plants under control to preserve soil moisture and suppress diseases.
Department of Primary Industries senior plant pathologist Grant Hollaway said grain losses attributed to disease in wheat were low this harvest, despite it being a high-risk season with heavy rain last summer.
Dr Hollaway said that was due to good management by growers last summer and in the growing season.
"The rust pressure because of the green bridge was the highest seen in a long time last year," he said.
"With the heavy rain, green bridge control was better than the previous year.
"It was hard to find volunteers with rust. But where they were, they were loaded."
Dr Hollaway said effective disease control measures began with spraying of volunteers and summer weeds after heavy rains last summer, followed by fungicide application to fertilisers and early spraying programs when there was a hint of disease in the growing season.
He said where no control measures were put in place, grain yield losses were as high as 20 per cent.
Dr Hollaway said there was still a big threat to crops in the new season, due to a significant rust spore carryover.
Much depended on the level of rainfall during summer.
"There is a high level of inoculum out there at the moment," he said.
"That means there is a risk of a disease outbreak.
"But a dry break will curtail it.
"Controlling the green bridge will not stop it (disease outbreak) but it will definitely slow it down."
