Fusarium Wilt
Fusarium oxysporum (multiple special forms)
Soil-borne fungus that blocks water-conducting vessels. Plants wilt on one side and progressively yellow and collapse.
Background
Fusarium oxysporum is actually many host-specific strains (formae speciales), each attacking a particular crop. F. oxysporum f.sp. lycopersici attacks tomato; f.sp. cubense causes Panama disease in banana; f.sp. conglutinans attacks brassicas. The fungus invades roots and grows inside the water-conducting xylem, blocking water flow and causing progressive wilt.
How to identify
- Yellowing and wilting often starting on one side of the plant
- Progressive upward yellowing and leaf death
- Cut the stem lengthwise — brown streaks in the vascular tissue (xylem) confirm fusarium
- Final collapse of the plant
Life cycle
Survives in soil as chlamydospores for many years. Infects through roots. Spreads within the plant via xylem. Spores liberated into soil when the plant dies.
Weather triggers
- Temperature: 18-32°C
- Warm soils (22-28C) favour disease. Cool soils slow symptom development.
Peak season (southern hemisphere)
Red = active season · Dark red outlined = this month
Affected vegetables & crops
Click any crop to see current prices and growing info.
Climate zones at risk
Organic & low-impact control
- No direct organic cure — manage by prevention and resistant varieties
- Solarisation can reduce soil inoculum in clear weather over 6-8 weeks
- High organic matter encourages suppressive soil microbes
Chemical control
- No effective chemical treatment once infected
- Commercial growers use soil fumigation pre-plant; not available for home gardens
Always read product labels — registrations change.
Prevention
- Choose resistant varieties — tomato cultivars with F or FF resistance codes
- Rotate susceptible crops on a 4-6 year cycle
- Do not move infested soil or plant material to new beds
- Remove and destroy affected plants (do not compost)
Companion planting
No direct companion plant suppresses Fusarium reliably.
Biosecurity
Panama disease Tropical Race 4 (a F. oxysporum strain on banana) is under strict quarantine.
Sources
- NSW DPI — Fusarium wilt in vegetables
- Queensland DAF — Fusarium wilt of tomato
Accuracy confidence: high. We update this library as new extension guidance is published.