Yellow spot of sugar cane

Yellow spot of sugar cane is a significant fungal disease caused by the pathogen Mycovellosiella koepkei (formerly known as Cercospora koepkei). The disease primarily impacts the foliage of the sugar cane plant, acting as a parasite that inhibits vital plant functions and leads to reduced yield quality.

The primary host for this pathogen is sugar cane (Saccharum officinarum). While it is common in various tropical and subtropical regions, the disease is particularly devastating in areas with high rainfall, where it can drastically reduce the photosynthetic capacity of the canopy and hinder the plant's ability to store sucrose.

The symptoms of yellow spot typically manifest as small, yellow, circular to oval lesions on the leaf blades. As the infection progresses, these spots often elongate along the leaf veins and turn a reddish-brown or dark brown color. In severe cases, the lesions coalesce, leading to extensive necrosis and premature drying of the leaves.

Environmental conditions are the main driver for the spread of Mycovellosiella koepkei. High humidity, warm temperatures, and frequent leaf wetness (from rain or dew) are essential for the germination of fungal spores. Wind and water splashes facilitate the movement of spores between plants, allowing the disease to spread rapidly throughout a field during wet seasons.

Managing yellow spot requires an integrated approach to minimize crop losses. Key strategies include the selection of resistant cane cultivars, which is the most sustainable method. Additionally, agronomic practices such as improving field drainage and ensuring adequate spacing to promote air circulation can significantly reduce infection risk. In some instances, the application of foliar fungicides is necessary to protect the crop during high-risk environmental conditions.