July 2025 pest watch: bacterial wilt
04 August 2025
4 August 2025
Bacterial wilt (Ralstonia solanacearum)
Bacterial wilt is a highly destructive disease that causes sudden wilt and death in a wide range of ornamental and agricultural crops. It affects more than 35 genera across 50 plant families, making it one of the most serious threats to nursery production.
Common hosts include:
- tomato, potato, eggplant, capsicum, and ginger
- dahlia, heliconia, strelitzia, zinnia, and geranium
- banana, custard apple, eucalyptus, and peanut.
Symptoms
Symptoms often start subtly – a slight leaf wilt or necrotic area – but rapidly progress. Plants typically collapse and die. Infected stems usually have darkened vascular tissue, and if you cut the stem and place it in water, bacterial ooze may stream out – a classic sign of infection.
Mature plants can carry the bacterium without showing symptoms, which increases the risk of spread. The pathogen moves easily through:
- irrigation and surface water
- contaminated tools and equipment
- cuttings taken from infected (but symptomless) plants.
Infection is incurable
Once a plant is infected, there is no cure. Infected material must be disposed of offsite, preferably by deep burial. Do not compost infected plants, as this can reinfect your site.
Prevention
- Monitor mother stock and new plant deliveries for early signs of disease.
- Maintain strict hygiene protocols for tools, water, and equipment.
Suspected infection? What next
Grow Help Australia offers six free plant disease diagnostics to all production nurseries until the end of 2025.
