CropAlert – Stripe Rust August 2024


CropAlert – Stripe Rust August 2024

Stripe rust has now been widely reported across Victoria since the first report on 22nd July in the Mallee and our crop alert dated 1st August 2024. The majority of the detections have been so far coincided with susceptible varieties (ex: Scepter) and where an up-front fungicide (ex: flutrifol) was not applied demonstrating the vulnerability of susceptible varieties to rust. In the high rainfall region, infections are also being reported in resistant varieties (Ex: RGT Cesario). It is important to note that RGT Cesario is rated resistant still due to the adult plant resistance (APR) and in all NVT testing, the resistance has been found effective currently. APR expression in wheat varieties is usually associated with temperature and they are more effective at higher temperatures (add range). Current cold and wet weather may not be favorable for APR expression, hence varieties with APR will need protection from rust during early crop growth stages until APR becomes effective at rust mitigation.

With conditions becoming favorable and wet weather around, it is likely that stripe rust will be more prevalent in wheat crops across Victoria. Therefore, it is recommended to monitor crops regularly for symptoms with a view to timely fungicide application if warranted. To maximise rust control and yield benefit, it is suggested that fungicide applications are timed at stem elongation (Z31) and flag leaf emergence (Z39) stages of the crop where possible. By doing so, the top three flag leaves that contribute to yield will be protected.

Stripe rust identification, management, and epidemiology can be found in ‘Identification & Management of Field Crop Diseases in Victoria’.

Growers and advisors are encouraged to adopt a three-step approach to assess stripe rust infection.

  1. Review variety ratings using a current cereal disease guide. To ensure the ratings are current do not use one from previous years. The current Victorian guide can be found here.
  2. Monitor crops closely for symptoms, focusing on more susceptible varieties more regularly.
  3. Use the StripeRustWM app to support foliar spray decision making. The app can be downloaded from the Apple and Google Play stores. A Click here to access user guide for those unfamiliar with the app.

Figure: Current status of cereal rust incidence in Victoria and NSW (Data source: University of Sydney).

Note: Submit a sample of rust to National rust surveillance program monitored by University of Sydney to enable pathotype (strain) detection and development of future resistant varieties. Follow Australian cereal rust survey for instructions on how to submit a sample. The latest rust report detailing the pathotypes of rust found from submitted samples can be found here. This report highlights the benefits of submitting rust samples, particularly in varieties which are rated as resistant and you believe are expressing more disease than they should.

 

Upcoming events

AFREN webinar – Southern region 2024 seasonal update – September 3

AFREN webinar – Pulse and mungbean 2024 seasonal update – September 6

Canola and Pulse field day – Kalkee – September 10

Field crops pathology Field Day – October 3 – more info to follow

Woomelang Pulse Field Day – October 8 – more info to follow

FAR Australia – Vic Crop Technology Centre Field Day (Gnarwarre) – 10th October

Southern Pulse Agronomy Field Day – October 30 – more info to follow

 

Horsham Field Crop Diseases research group (Agriculture Victoria)

For further information and assistance in diagnosing stripe rust, contact the Horsham Field Crop Diseases research group.

Ph: (03) 4344 3111

Email: [email protected]

 

Kind regards,

The Horsham Field Crop Pathology and CropSafe teams

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