Tilletia boutelouae bunt

The fungus Tilletia boutelouae is a specialized pathogen responsible for a specific type of bunt disease affecting grasses of the genus Bouteloua. As a member of the Ustilaginaceae family, it functions as a systemic parasite that colonizes the host plant during its early developmental stages and completes its cycle within the plant's reproductive structures.

The disease primarily targets the inflorescences of the host grass. Instead of producing viable seeds, the plant develops sori or "bunt balls," which are filled with millions of microscopic teliospores. These spores are released when the fungal membrane ruptures, effectively contaminating the soil and neighboring plants with the pathogen.

The symptoms are most diagnostic during the heading stage. You may notice that infected spikes look stunted or deformed. The individual florets often appear swollen because the internal tissues are replaced by the black, powdery spore mass of the fungus. This visual change is the most reliable way to identify the disease in the field.

The environmental factors play a crucial role in disease establishment. Cool, moist soil conditions during seed germination promote the infection process, as the fungal spores require specific moisture levels to germinate and penetrate the coleoptile of the developing seedling. Once established, the fungus grows systemically with the plant.

Management of Tilletia boutelouae relies heavily on proactive agricultural practices. Key strategies include:

• Utilizing disease-free, certified seeds.
• Applying chemical seed treatments to eliminate surface and systemic infections.
• Practicing crop rotation to reduce inoculum levels in the soil.
• Removing and destroying heavily infected plants before spore dispersal occurs.