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Plant & Pest Advisory – July 13, 2025 – Andy Wyenandt
There have been a few reports of Southern blight (Sclerotinia rolfsii) and White
mold (Sclerotinia sclerotiorum) on tomato and pepper in New Jersey. Southern
blight is much more common in vegetable areas 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.
White mold is more common than Southern blight in New Jersey, and like
Southern blight, once introduced into 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 years causing significant problems. All infected
plants need to be removed immediately and disposed of properly to help reduce
the chances of sclerotia returning to the soil.
For more information on chemical control please see the 2024/2025 mid-Atlantic
Commercial Vegetable Production Recommendations Guide.