Marasmius blight

White fungal mycelium can be observed at the base of the stalks, firmly wrapping around the leaf sheaths and invading the lower stem tissues.

Under conditions of high humidity, the pathogen forms small white or yellowish mushroom fruiting bodies on the infected stalks and leaves.

Infected stalks often lose their sugar content, become thin, and exhibit significant signs of stunted growth compared to healthy plants.

As the infection progresses, the root system begins to die off, leading to the overall decay of the plant and sometimes causing the stool to collapse.

The causative agent of the disease is the basidiomycete fungus Marasmius sacchari, a specialized parasite that targets the base and stems of sugarcane.

This fungus acts as a facultative parasite, capable of surviving as a saprophyte on dead plant debris and becoming aggressive under favorable conditions.

Mycelium serves as the primary reservoir for the pathogen, persisting in the soil and on infected vegetative planting material between growing seasons.

Spore dispersal occurs through wind currents, rain splash, and physical movement of contaminated planting material across the fields.

The pathogen secretes enzymatic complexes that break down plant tissues, effectively disrupting water and nutrient transport throughout the stalk.

The development of Marasmius blight is significantly encouraged by high ambient humidity and prolonged periods of soil moisture.

The fungus thrives within a temperature range of 25–30°C, making it a prevalent issue in various tropical and subtropical sugar-producing regions.

Dense crop stands with poor air circulation create stagnant microclimates that facilitate the rapid spread of the fungal infection.

Stressed plants, whether due to nutritional deficiencies or insect damage, show a decreased ability to resist the penetration of the fungus.

Inadequate sanitation practices, such as leaving large amounts of crop residue on the field after harvest, contribute to a high inoculum load in the soil.

The most significant economic loss is the reduction in sucrose content, as the fungus consumes the energy reserves stored within the stalks.

Affected tissues become weak, leading to widespread lodging of the crop, which complicates mechanical harvesting and increases operational costs.

Severe infestations cause high mortality rates among young shoots, resulting in uneven stands and the potential need for costly replanting.

Infected stalks have poor quality for use as planting material, as they carry the pathogen to new plots, continuing the cycle of disease.

Yield losses can reach 20–30% in susceptible varieties when weather conditions remain consistently favorable for the fungus for extended periods.

The most effective strategy is the use of certified disease-free planting material to prevent the introduction of the pathogen into clean fields.

Implementing a proper crop rotation strategy helps to break the life cycle of the pathogen and reduce its population in the soil over time.

Post-harvest sanitation, including the destruction of debris through burning or deep tillage, is essential to minimize the primary source of infection.

Maintaining optimal soil fertility and managing water irrigation levels can enhance the plant's natural defense mechanisms against fungal diseases.

• Thinning of dense stands to improve airflow and reduce humidity.
• Regular monitoring and roguing of infected stools in the field.
• Fungicide treatment of cane setts prior to planting.
• Deployment of resistant or tolerant sugarcane cultivars.