Miscanthus anthracnose

The disease is caused by the pathogenic fungus Colletotrichum miscanthi, a member of the Ascomycota division. This pathogen is known to cause anthracnose, a severe fungal condition affecting ornamental and bioenergy grasses. The fungus survives in plant debris, soil, and occasionally within infected seed material, which acts as a primary inoculum source for subsequent growing seasons.

The primary host range is limited to species of the genus Miscanthus, which are increasingly cultivated for bioenergy production. The fungus attacks the aerial parts of the plants, including leaves and stems. By damaging plant tissues, it significantly interferes with growth, leading to reduced yield and poor quality of the harvested biomass, which is critical for industrial applications.

Symptoms initially appear as small, water-soaked spots on leaves that eventually enlarge into elongated necrotic lesions. As the infection progresses, these lesions often turn brown or grey, and small, dark fruiting bodies (acervuli) become visible within the dead tissue. These structures produce mass amounts of spores that allow for rapid secondary spread throughout the field during the growing season.

The development of the fungus is heavily influenced by environmental factors such as high humidity, frequent rainfall, and moderate temperatures. Spores are primarily dispersed through rain splashing and wind, allowing the pathogen to move quickly between plants in dense stands. Mechanical operations, such as harvesting or trimming, without proper sanitization can also facilitate the spread of spores to healthy areas.

Management strategies focus on integrating cultural and chemical practices to minimize disease impact. Cultural control measures include selecting resistant cultivars, maintaining proper plant spacing to improve air circulation, and rigorous sanitation practices such as removing and destroying infected plant material after harvest. Targeted fungicide applications may be necessary during wet conditions to protect crops and maintain healthy yield levels.