There have been a number of reports of Southern blight (Athelia rolfsii; formerly Sclerotinia rolfsii) on tomato and pepper in New Jersey. Southern blight is much more common in vegetable growing regions south of the state where summer temperatures remain hotter (above 90°F) for longer periods of time. Like white mold, it can survive in the soil for many years. Symptoms of Southern blight include infection at the base of the stem at the soil line. The resulting infection will girdle the plant causing wilt and death. The fungus will produce white, cottony mycelium and very small, spherical sclerotia which are often have a tannish, brown color.
In most years, White mold is more common than Southern blight in New Jersey; however the hotter temperatures and wet weather patterns across the state this summer has led to more Southern blight being reported. Like Southern blight, once White mold is present in a field or high tunnel it can very difficult to control. The pathogen produces large black sclerotia on the surface and inside infected stems. If sclerotia of either pathogen make their way back into the soil, both can survive for many years causing significant long-term problems.
All infected plants need to be removed from the field or high tunnel immediately and disposed of properly to help reduce the chances of sclerotia returning to the soil. Timely fungicide applications applied through drip or as directed sprays at the base of the plant can help mitigate disease pressure. For more information on control of both diseases please see the 2026/2027 mid-Atlantic Commercial Vegetable Production Recommendations Guide.
Symptoms of Southern blight on infected pepper plant. Note the numerous, small white to tan colored sclerotia on the stem.
White mold of tomato. Note the large black sclerotia developing inside the brittle stems.
