Bacterial spot: identify, prevent, control

Worst in warm, wet, humid weather through summer, December to March.

Bacterial spot is a bacterial disease of tomatoes and capsicum that peppers leaves and fruit with small dark spots. It spreads fast in warm, wet, humid weather through splashing water and is hard to cure, so prevention and clean seed matter most.

How to identify it

• Small dark water-soaked spots on leaves, sometimes with a yellow halo
• Raised scabby spots on fruit
• Spots merging and leaves yellowing and dropping
• Worst in warm, wet, humid conditions

How to prevent it

• Use clean, certified seed and disease-free seedlings
• Rotate crops and avoid replanting tomatoes and capsicum in the same bed
• Water at the base and keep foliage dry
• Space and stake plants for good airflow

Organic control, step by step

• Remove and bin affected leaves and fruit promptly
• Avoid working among wet plants, which spreads the bacteria
• Spray a copper-based product as a protectant in wet weather, following label rates
• Repeat copper sprays after rain through the risk period
• Clean tools and stakes between plants and seasons
• Clear all infected debris and do not compost it

Plants it attacks