Rust

Updated June 2026

Worst in mild, humid weather through late summer and autumn, January to May.

Rust is a fungal disease that erupts as orange, brown or yellow pustules on leaves and stems of beans, garlic, leeks, silverbeet and many others. It spreads on the wind and on wet foliage, weakening plants and cutting yields, and badly hit crops are best removed.

How to identify

• Raised orange, brown or yellow pustules, mostly on leaf undersides
• Yellow flecks on the upper surface above the pustules
• Leaves yellowing, drying and dropping early
• Coloured dust on your fingers when you brush an infected leaf

How to prevent

• Space plants and keep airflow open so leaves dry fast
• Water at the base and avoid wetting foliage
• Rotate susceptible crops like beans, garlic and leeks
• Grow rust-resistant varieties where available and avoid overcrowding

How to control organically

• Remove and bin affected leaves promptly, never compost them
• Pull out and dispose of badly infected plants to stop spores spreading
• Spray a copper or sulphur-based fungicide early, covering leaf undersides
• Clear all infected debris at the end of the season
• Avoid working among plants while the foliage is wet