The impact of stripe rust can be reduced through an integrated crop management approach according to latest research from the Department of Agriculture, Western Australia.

Plant pathologist Geoff Thomas, who is speaking at the Department’s Agribusiness Crop Updates next week, said wheat stripe rust was a significant problem in 2004 in Western Australia’s eastern and south eastern grainbelt.

Stripe rust management will also be discussed with growers at the Regional Crop Updates in Bencubbuin on 21 February, Carrabin on 22 February and Northam on 24 February.

“By encompassing green bridge management, variety choice, seed dressing or in-furrow fungicides, crop monitoring and foliar fungicides, the impact of stripe rust can be reduced,” he said.

“Experiments and crop observations conducted by the Department across the wheatbelt reinforced key aspects of the biology and management of stripe rust.

“The observations demonstrated that there is a strong association between ‘green bridge’ areas and stripe rust outbreaks.

He said the overlap of regenerated summer cereals and autumn sown susceptible wheat with conventional winter plantings, resulted in the early stripe rust outbreak in 2004. 

“It is recommended that growers destroy self sown wheat at young stages, well in advance of seeding, to greatly reduce the risk of early stripe rust in crops.

Mr Thomas said the integrated management of stripe rust combining, variety resistance and fungicide at seeding or foliar sprays, was also proving to be essential in areas of high risk.

“Varieties that are very susceptible to stripe rust should be avoided as they greatly increase the development of the disease, thus increasing the overall epidemic and yield loss,” he said.

“More resistant varieties will reduce stripe rust infection in the cropping season and also reduce green bridge carryover next season.”

Mr Thomas said that in green bridge and adjacent areas, early crop protection with stripe rust fungicides could significantly delay or reduce the requirement for fungicide sprays later in the season.

“Early protection can consist of seed dressing or in-furrow fungicide at the time of planting or a fungicide spray on young crops,” he said.

“Varieties categorised intermediate for stripe rust develop resistance increasingly from late stem elongation to heading/flowering.

“These varieties can benefit from early fungicide protection but their requirement for fungicide protection later in the season is considerably lower due to adult plant resistance.”

Mr Thomas said active monitoring, with a view to the timely application of foliar fungicides, was an important feature of disease management in highly susceptible varieties.

“Good results can be achieved with standard fungicide rates, particularly if applied at the very earliest signs of the disease.”

“Seasonal climatic factors also influence stripe rust severity and spread.  In 2004, dry spring conditions reduced the impact of the disease in some areas.” 

Mr Thomas said tailoring the available range of management options to suit growers needs was important to maximise crop returns under variable seasonal risk situations.

Agribusiness Crop Updates is supported by the Grains Research and Development Corporation.