Red rot of leaf sheath and sprout rot

The disease known as red rot of leaf sheath and sprout rot is caused by the pathogenic fungus Athelia rolfsii (often identified by its Sclerotium rolfsii asexual stage). This organism is a devastating soil-borne fungus known for its wide host range and ability to persist in the soil for extended periods, posing a constant threat to agricultural stability.

While the pathogen affects various crops, it is particularly destructive to Sugar Cane plantations. The fungus typically attacks the base of the stems and the leaf sheaths, causing significant tissue degradation and inhibiting the plant's physiological ability to transport nutrients and water effectively.

Early symptoms include the formation of reddish-brown necrotic lesions on the leaf sheaths surrounding the cane stalk. As the disease progresses, these lesions expand, and under humid conditions, a characteristic white, fan-like mycelial growth becomes visible. Eventually, small, mustard-seed-sized sclerotia develop, which are key indicators of this specific fungal infection.

The development of the disease is highly dependent on environmental conditions, specifically high soil moisture levels and temperatures ranging from 25°C to 30°C. High plant density and poor drainage further exacerbate the spread of the fungus within the field, creating an optimal microclimate for infection spread via water and agricultural machinery.

The damage caused by this disease is significant, often leading to reduced cane yield and lower sugar content. To effectively combat it, farmers should focus on cultural practices such as improving field drainage, strictly following crop rotation, and removing infected debris. Additionally, the application of targeted soil fungicides during the early stages of the crop cycle can prevent widespread infection.