Sclerotinia sclerotiorum is a plant pathogenic fungus and can cause a disease called white mold if conditions are conducive.

A key characteristic of this pathogen is its ability to produce black resting structures known as sclerotia and white fuzzy growths of mycelium on the plant it infects.

When S. sclerotiorum is onset in the field by favorable environmental conditions, losses can be great and control measures should be considered.

Sclerotinia sclerotiorum” (sometimes called white mold) is a fungal (Ascomycota) pathogen that infects a broad range of plants, affecting over 400 species across multiple families, including Brassicaceae (Cruciferae), Fabaceae (Leguminosae), Solanaceae, Asteraceae, and Apiaceae (Umbelliferae).

White mold can affect their hosts at any stage of growth, including seedlings, mature plants, and harvested products.

[4] White mold is the most common pathogen that affects sunflower and has been found to cause reduction in yield throughout the world including the United States, northern Europe, Great Britain and Russia.

[5] Economically significant hosts include Vicia faba, for which Lithourgidis et al have done extensive work over the years.

[8][9] For soybeans, crop yields are inversely correlated with the incidence of Sclerotinia stem rot; an estimated of 0.25 metric ton per ha is lost for each 10% increment of diseased plants.

During late summer to early fall, the fungus will produce a survival structure called a sclerotium either on or inside the tissues of a host plant.

S. sclerotiorum sclerotia can remain viable for at least three years[12] and germinate to produce fruiting bodies called apothecia, which are small, thin stalks ending with a cup-like structure about 3–6 mm in diameter.

S. sclerotiorum is capable of invading nearly all tissue types including stems, foliage, flowers, fruits, and roots.

They find that initial infection is not noticeably dependent on oxalate (although lesion expansion does require it for pH reduction and chelation of calcium).

[12] Good weed control can also limit the amount of host plants in a field and reduce white mold pressure.

[18] Coniothyrium minitans, a coelomycete distributed worldwide, is a pathogen of S. sclerotiorum[19][20] and is a commercial biocontrol agent for sclerotinia stem rot.

Due to the ubiquitous nature of this fungus in temperate climates, research has shown that wild-type sclerotium-forming isolates would be safe to use in permanent grass/clover pastures in these regions of the world,[27] and its application for weed control would not to lead unusual levels of inoculum (airborne ascospores and soil-borne sclerotia) in the environment beyond the application site or increased disease risk to non-target plants because of its limited dispersibility.