Gnomonia iliau of sugarcane

The causal agent of this disease is the fungus Gnomonia iliau, which is a specialized phytopathogen primarily affecting sugarcane. It is classified as an ascomycete fungus and is known for its ability to cause severe rotting of the seedlings and base stems. The disease is recognized for its potential to compromise the establishment of healthy sugarcane stands.

The primary host for Gnomonia iliau is sugarcane (Saccharum officinarum). The fungus specifically targets young shoots, stalks, and the root system. Commercial sugarcane plantations are most susceptible during the early stages of growth, especially when propagation relies on cuttings placed directly into moist soil conditions.

Symptoms of the infection include the formation of dark, necrotic lesions located at the base of the young stalks. As the disease progresses, the internal tissues of the stem become soft and necrotic, often covered by a whitish mycelial growth. If left untreated, the plant tissues deteriorate, leading to stunted growth, wilting, and eventually the death of the entire young plant.

The development and spread of Gnomonia iliau are strongly favored by high soil moisture and warm temperatures. These conditions create an ideal microclimate for fungal proliferation and spore germination. The fungus can persist in crop residues and soil, making it a persistent challenge for farmers working in humid, tropical climates where environmental conditions remain conducive to infection.

• Selection of disease-free planting material.
• Implementation of proper crop rotation cycles.
• Improved drainage systems in planting fields.
• Fungicidal treatment of seed cuttings before sowing.

The economic impact of this pathogen is significant due to reduced crop stands and potential harvest losses. Effective management requires an integrated approach that combines cultural practices, such as ensuring adequate soil aeration, and the use of chemical controls. Preventing the initial entry of the pathogen into clean fields remains the most important strategy for minimizing long-term damage.