Rust: identify, prevent, control

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

Rust is a fungal disease that shows as orange, brown or yellow pustules on leaves and stems, common on beans, leeks, garlic and silverbeet. It spreads on wind and water in humid weather, and a bad outbreak weakens plants and cuts yields.

How to identify it

• Raised orange, brown or yellow pustules, mostly on leaf undersides
• Coloured spores that rub off onto your fingers
• Yellowing leaves that dry off and drop early
• Heavily infected plants looking scorched and weak

How to prevent it

• Space plants for good airflow and avoid overcrowding
• Water at the base and keep foliage dry, especially in the evening
• Rotate susceptible crops like beans, garlic and leeks each season
• Grow rust-resistant varieties where available

Organic control, step by step

• Remove and bin affected leaves as soon as pustules appear
• Pull out and dispose of badly infected plants rather than composting them
• Spray a wettable sulphur or copper fungicide as a protectant, following label rates
• Repeat protectant sprays after rain in humid weather
• Avoid working among wet plants, which spreads the spores
• Clear all infected debris at the end of the season

Plants it attacks