Australia
January 31, 2012
Everygrain grower should have a rust management plan drawn up at the beginning of the season.
While rust can be controlled in susceptible and very susceptible varieties through the careful use of fungicides, growing these varieties can jeopardises current and future disease resistance.
The key planks of a grower’s rust management plan should include:
- • Removing the green bridge (volunteer plants) at least four weeks before the intended start of sowing in a region.
- • Growing varieties with adequate resistance to stem, stripe and leaf rusts.
- • If needed, applying fungicides to seed or fertilisers for early season rust suppression.
- • Monitoring crops for rust and if needed, applying foliar fungicides for disease control.
A poorly managed crop, combined with untreated volunteers following harvest, can contribute significantly to building high inoculum levels within and between seasons.
If there are high levels of rust in a region then you, your neighbour and your industry are at risk. High levels of rust inoculum increases the chance of rusts mutating, putting effective rust-resistance genes at risk.
Plan your rust response at the beginning of the season to ensure you are not left behind in the event of a rust outbreak.
Because rust is an airborne disease, the spores can spread quickly between regions. And the earlier in a season a rust epidemic starts, the greater the potential yield loss.
Crops must be monitored to detect rust early. Timing is critical for the effective control of rust diseases with fungicides. Fungicide treatments will be most effective when adopted across a region and applied early in a disease epidemic as they will greatly reduce the inoculum levels in a district.
However, there are a few options that growers can roll out at seeding time to ensure they have a head start in rust prevention.
Growers who select varieties that are susceptible or partly resistant to rust should consider applying a fungicide with rust activity to seed or fertiliser at sowing. These up-front treatments can help reduce early disease build-up and in some regions, may provide useful rust suppression in varieties without adequate rust resistance. Crops should then be carefully monitored for rust development with a foliar fungicide applied early in the disease’s development.
These options, plus careful crop monitoring throughout the season, also apply for moderately resistant to moderately susceptible varieties, however only one or more may need to be used, depending on the season’s rust risk.
For resistant and moderately resistant varieties, these rust management options at sowing are not necessary.
Experience in 2011 showed that growers with a management plan can effectively control rust if they use resistant varieties and/or fungicides applied to seed or fertiliser at sowing and foliar sprays in a timely fashion during the season.
The Australian Cereal Rust Control Program Consultative Committee has developed a Rust Bust check list to help growers be prepared:
- Grow varieties with adequate resistance to stem, stripe and leaf rust.
- Phase out very susceptible (VS) or susceptible (S) varieties from your rotation. Otherwise develop a rust management plan.
- When selecting varieties, ensure you have a rust management strategy, including green bridge control and intended fungicide use.
- Know the seedling and adult plant rust resistance characteristics of the varieties you decide to grow, and identify whether they require chemical support.
- Remove the green bridge (volunteer plants) at least four weeks before the intended sowing date.
- Closely monitor crops to enable early rust detection and management.
- Use appropriate fungicide support to maximise crop performance and minimise disease build-up.
- Talk to your neighbour about your rust situation so management can be tackled more efficiently.
The Rust Bust is an initiative of the Australian Cereal Rust Control Program Consultative Committee, supported by the Grains Research and Development Corporation.
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