Southern Blight
Risk near you, next 48h
See whether your local forecast favours this disease right now.
When it strikes
Treat, then re-check in 5–7 days
Pick off the worst material, apply the organic option below, and look again after five to seven days. If the spread continued, escalate rather than repeating the same treatment.
Rain and irrigation splash
Water splashing off soil and infected leaves carries it upward and along the row. Watering at the base and mulching the soil surface break the route.
It carries over to next season in soil, debris or seed — which is why rotation matters here, not just treatment.
Keep out of the compost
This survives a garden heap. Bag it for municipal green waste, which is composted industrially at temperatures a garden heap cannot reach, or burn it where that is permitted.
When and where to look
Scout the planting while temperatures hold between 25°C and 35°C, with humidity above 80%, after rain or heavy dew, while the leaves are still wet. Risk builds after roughly 6 unbroken hours of those conditions, so the morning after such a night is the moment to look.
The signs that lead here
About
Southern blight (Sclerotium rolfsii) is a hot-weather soil-borne fungus attacking tomatoes, peppers, beans and many vegetables at the stem base, common in warm humid climates.
Symptoms
Sudden wilting and yellowing; a white fan of fungal threads at the soil line studded with tan, mustard-seed-sized resting bodies; rapid plant collapse.
Organic Treatment
Remove infected plants with surrounding soil, deep-bury or solarise, add compost, and mulch with a barrier that keeps the fungus off the stem.
Chemical Treatment
Flutolanil or PCNB soil treatment in commercial production; limited options in the home garden.
Prevention
Rotate with cereals, bury crop debris deeply, raise soil pH, and avoid mulching directly against stems in hot weather.
Related problems
Southern Blight risk by location
Each location has a month-by-month profile computed from the weather archive: how many hours a year actually meet this disease’s thresholds.