GRAINGROWERS across NSW and southern Queensland expect to be battling plant pathogens including ascochyta blight in chickpeas and cereal rust in wheat into the last stages of pre-harvest plant growth.
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The spring Cereal Rust Report issued by the Grains Research and Development Corporation (GRDC)-support Plant Breeding Institute (PBI) shows pathotype identifications indicate the presence of ‘Jackie’ and ‘WA Yr17’ pathotypes at equal frequency.
The ‘Jackie Yr27’ pathotype has been reported for the first time since October 2008.
Dr Colin Wellings of the University of Sydney says ideal moisture levels across most of eastern Australia have provided favourable conditions for cereal production in spring, while also exacerbating foliar disease problems including rust.
“The stripe rust situation in eastern Australia indicates that the pathogen population is at sufficient levels to cause problems if timely action is not taken in varieties known to be vulnerable,” Dr Wellings said.
“Stripe rust in South Australia was detected in early September and has possibly been influenced by the population developing in the Riverina and Victoria’s Wimmera regions.”
Stripe rust has not been reported from WA in 2010.
Dr Wellings said although survey samples may not necessarily reflect the true nature of the dimensions of the stripe rust population in wheat growing regions, some important points worth noting were:
- The high frequency of the ‘WA Yr17’ pathotype indicates that varieties likely to be vulnerable (Barham, Bowie, Camm, Derrimut, Endure, Fang, Hornet, Mace, Marombi, Pugsley, QAL 2000, Sunstate, Ventura, Yenda, Young) will require careful monitoring and timely fungicide response.
- There is significant stripe rust pressure across most of southern NSW (eastern high rainfall zone, slopes, Riverina) and Victoria (north east, Mallee, Wimmera, southern high rainfall zone). Variety responses need to be carefully assessed and action to protect flag leaves needs to be taken where appropriate and as resources allow.
- Where resources might be limiting (availability of chemical/contractor/paddock access), prioritise varieties at risk and in high yield situations.
- Vulnerable varieties treated at seeding will need to be monitored for emerging infection and sprayed in a timely manner, hopefully with the flag leaf emerged and intact.
- Several varieties in the moderately resistant to moderately susceptible category have responded well to early fungicide protection in 2010.
Stem rust and leaf rust sightings are also on the increase, although cool temperatures are assisting in delaying the development of these diseases. Growers and advisors are urged to keep a close eye on these diseases in spring.
* Visit www.grdc.com.au/rustlinks.
