Fungal diseasesSevere

White Mold (Sclerotinia)

Risk near you, next 48h

See whether your local forecast favours this disease right now.

When it strikes

Temperature

10–24°C

Humidity

≥90%

Leaf wetness

Required

Season

Spring, Summer, Autumn

Remove affected material now

Take out the affected leaves, shoots or whole plants before the next wet spell, bag them as you cut, and wash your hands and tools before touching healthy plants.

Soil and crop debris

It waits in the ground or in last season's debris, so removing the plant does not clear the bed. Rotation and debris removal are the working controls.

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 10°C and 24°C, with humidity above 90%, after rain or heavy dew, while the leaves are still wet. Risk builds after roughly 12 unbroken hours of those conditions, so the morning after such a night is the moment to look.

Jan Feb Mar Apr May Jun Jul Aug Sept Oct Nov Dec

The months this problem is listed as active. Pick one to see the garden work for that time of year.

Rule these out first

Same category, and at least one host crop in common — so they are genuinely confusable in the same part of the garden.

The signs that lead here

Full problem lists for these crops

About

White mold (Sclerotinia sclerotiorum) attacks beans, lettuce, carrots and over 400 plant species in cool, moist, dense canopies, producing hard black resting bodies that survive years in soil.

Symptoms

Water-soaked stem and pod rot covered in dense cottony white mould, later embedded with hard black pellets (sclerotia); sudden wilting of branches above the rot.

Organic Treatment

Remove and destroy infected plants with the soil around them, improve airflow, avoid dense planting, and apply a Coniothyrium minitans biocontrol where available.

Chemical Treatment

Boscalid or fluazinam applied at early bloom, when most infections begin.

Prevention

Widen spacing, rotate with cereals or corn, avoid over-irrigation, and bury sclerotia deep with tillage.

Crops at risk