Leaf rust in wheat
- Gairdner
James Bee (Elders) has found wheat leaf rust (WLR) in tillering Harper wheat near Gairdner on the south coast of WA. It was a widespread crop infection. James commented that he had observed several pustules on the older leaves on multiple plants in multiple paddocks across the farm. He had only observed WLR on this one farm which was growing Harper, Cobra and King Rock wheat varieties.
Growers and consultants are urged to check wheat crops for WLR and the likelihood of finding this disease will be greater if;
- Leaf rust was present in the area in 2016.
- Wheat volunteers, which may have carried over last season’s WLR inoculum, were present nearby in summer/autumn.
- A seed dressing or in-furrow fungicide with protection against WLR wasn’t applied.
- Wheat varieties sown are susceptible (S) to moderately susceptible (MS) to WLR. In this case Harper is rated moderately resistant moderately susceptible (MRMS#) to WLR as an adult, Cobra is rated moderately resistant (MR) and King Rock is rated MS#.
To find out the susceptibility of different wheat varieties visit the department’s latest wheat disease ratings page. It is important to note that with recent leaf rust incursions (2013 and 2015) the resistance of a variety can be dependent on the pathotype affecting the crop. Both pathotypes are present across the state. A rating with # indicates that the variety is potentially more susceptible to the newer pathotype.
When checking crops growers and consultants are also urged to look into the bottom of the canopy and stems for the presence of stem rust.
Agriculture and food plant pathologist Kith Jayasena says that in more susceptible varieties where leaf rust is present, it is important to halt the progression of disease. If rust is spreading through the crop it may be helpful to apply a foliar fungicide registered for leaf rust control at late tillering to stem extension, during post emergence weed control, to minimise leaf rust damage and limit further spread into other parts of the region.
If WLR is found growers and consultants are strongly urged to participate in the Australian cereal rust survey and submit samples to the University of Sydney, Private Bag 4011, Narellan, NSW 2567 for pathotype testing.
For fungicide information refer to the department’s Registered foliar fungicides for cereals in Western Australia page.
For more information on diagnosing and managing this disease refer to the department’s Diagnosing leaf rust of wheat and Managing stripe rust and leaf rust in wheat in Western Australia pages.
For more information contact Kithsiri Jayasena, Plant Pathologist, Albany on +61 (0)8 9892 8477, Geoff Thomas, Plant Pathologist, South Perth on +61 (0)8 9368 3262 or Andrea Hills, Plant Pathologist, Esperance on +61 (0)8 9083 1144.