Sclerotinia Sclerotiorum - Life Cycle

Life Cycle

The lifecycle of Sclerotinia sclerotiorum can be described as monocyclic, as there are no secondary inoculums produced. During late summer/ early fall the fungus will produce a survival structure called a sclerotium either on or inside the tissues of a host plant. The following spring the dormant sclerotia will germinate to produce fruiting bodies called apothecia, which are small, thin stalks ending with a cup-like structure about 5-15mm in diameter (similar in shape to a small mushroom). The cup of the apothecium is lined with acsi, in which the ascospores are contained. When the ascospores are released from the asci, they are carried by the wind until they land on a suitable host. The ascospores will then germinate on the host and begin to invade the host’s tissues via mycelium, causing infection. S. sclerotiorum is capable of invading nearly all tissue types including stems, foliage, flowers, fruits, and roots. Eventually white, fluffy mycelium will begin to grow on the surface of the infected tissues. At the end of the growing season, S. sclerotiorum will once again produce sclerotia. The sclerotia will then remain on the surface of the ground or in the soil, on either living or dead plant parts until the next season. The lifecycle will then continue respectively.